@article {pmid31207046, year = {2019}, author = {Czechowska, K and Lannigan, J and Wang, L and Arcidiacono, J and Ashhurst, TM and Barnard, RM and Bauer, S and Bispo, C and Bonilla, DL and Brinkman, RR and Cabanski, M and Chang, HD and Chakrabarti, L and Chojnowski, G and Cotleur, B and Degheidy, H and Dela Cruz, GV and Eck, S and Elliott, J and Errington, R and Filby, A and Gagnon, D and Gardner, R and Green, C and Gregory, M and Groves, CJ and Hall, C and Hammes, F and Hedrick, M and Hoffman, R and Icha, J and Ivaska, J and Jenner, DC and Jones, D and Kerckhof, FM and Kukat, C and Lanham, D and Leavesley, S and Lee, M and Lin-Gibson, S and Litwin, V and Liu, Y and Molloy, J and Moore, JS and Müller, S and Nedbal, J and Niesner, R and Nitta, N and Ohlsson-Wilhelm, B and Paul, NE and Perfetto, S and Portat, Z and Props, R and Radtke, S and Rayanki, R and Rieger, A and Rogers, S and Rubbens, P and Salomon, R and Schiemann, M and Sharpe, J and Sonder, SU and Stewart, JJ and Sun, Y and Ulrich, H and Van Isterdael, G and Vitaliti, A and van Vreden, C and Weber, M and Zimmermann, J and Vacca, G and Wallace, P and Tárnok, A}, title = {Cyt-Geist: Current and Future Challenges in Cytometry: Reports of the CYTO 2018 Conference Workshops.}, journal = {Cytometry. Part A : the journal of the International Society for Analytical Cytology}, volume = {95}, number = {6}, pages = {598-644}, doi = {10.1002/cyto.a.23777}, pmid = {31207046}, issn = {1552-4930}, }
@article {pmid31205409, year = {2019}, author = {Yao, R and Xu, L and Lu, G and Zhu, L}, title = {Evaluation of the Function of Wild Animal Gut Microbiomes Using Next-Generation Sequencing and Bioinformatics and its Relevance to Animal Conservation.}, journal = {Evolutionary bioinformatics online}, volume = {15}, number = {}, pages = {1176934319848438}, doi = {10.1177/1176934319848438}, pmid = {31205409}, issn = {1176-9343}, abstract = {The relationship between animal conservation and the animal gut microbiome is a hot topic in current microbial ecology research. Our group has recently revealed that the occurrence of diverse combinations of gut microbial compositions and functions (metagenomics) in Père David's deer (Elaphurus davidianus) populations is likely to lead to increased evolutionary potential and resilience in response to environmental changes. Thus, considering the effects of diet on the gut microbiome and the importance of a stable gut microbial community to host health, we suggest that a transitional buffer period (with feeding on a regular diet and a diet from the translocation habitat) is needed before animal translocation. When the gut microbiome enters into relatively stable stages and adapts to the new diet from the translocation site, the time is suitable for translocation. Long-term monitoring of the gut microbiomes of translocated animals (by collecting fresh feces and carrying out next-generation sequencing) is still necessary after their translocation.}, }
@article {pmid31204896, year = {2019}, author = {Tian, H and Hui, M and Pan, P and Huang, J and Chen, L and Zhao, J}, title = {Performance and microbial ecology of biofilms adhering on aerated membrane with distinctive conditions for the treatment of domestic sewage.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-29}, doi = {10.1080/09593330.2019.1631890}, pmid = {31204896}, issn = {1479-487X}, abstract = {When used to treat domestic wastewater, biofilms adhering to oxygen-permeable membranes are generally altered by environmental conditions. In this study, the effect of common conditions, including salinity, temperature, air-supplying pressure, flow velocity, influent COD, and NH4-N on the biofilm structure were determined. Principal component analysis revealed that archaeal community was more easily affected by the changing conditions than bacteria. The subsequent redundancy analysis showed that salinity had the most influence on bacteria, followed by temperature, influent COD, flow velocity, pressure, and influent NH4-N. In archaea, temperature had the highest effect, followed by flow velocity, salinity, influent NH4-N, pressure, and influent COD. The key bacterial class Anaerolineae was not easily influenced by the above conditions, but the population probably contributed to the nitrogen removal. Gammaproteobacteria was promoted significantly by influent NH4-N concentration, salinity, and pressure. Betaproteobacteria and Deltaproteobacteria were apparently inhibited by the high salinity and contributed to the organic compound degradation. Flow velocity primarily promoted the growth of Alphaproteobacteria. Candidatus Nitrososphaera had a higher tolerance for salinity but lower tolerance for influent NH4-N than Nitrosomonas. The former probably played a more crucial role in ammoxidation. Methanomethylovorans might disrupt nitrogen removal because it could consume the carbon source for denitrification.}, }
@article {pmid31202406, year = {2019}, author = {Wedel, C and Wenning, M and Dettling, A and Scherer, S and Hinrichs, J}, title = {Resistance of thermophilic spore formers isolated from milk and whey products towards cleaning-in-place conditions: Influence of pH, temperature and milk residues.}, journal = {Food microbiology}, volume = {83}, number = {}, pages = {150-158}, doi = {10.1016/j.fm.2019.05.002}, pmid = {31202406}, issn = {1095-9998}, abstract = {The occurrence of thermophilic spore formers in dairy powders is a major concern for producers worldwide. This study aims to investigate the resistance of thermophilic endospores towards cleaning solutions typically used for cleaning-in-place in dairy manufacturing plants. From eleven tested strains, all were able to survive an alkaline treatment (NaOH) at 65 °C for 10 min (0.5%), whereas at concentrations of 2% eight strains withstood the treatment. Acid solutions were more sporicidal. At 0.5% of HNO3, only three strains survived the treatment. Milk impurities reduced the inactivation effect of the NaOH solutions towards thermophilic spore formers. For two selected strains, a detailed kinetic inactivation in NaOH and HNO3 solutions at different temperatures was performed and non-log-linear inactivation curves were observed. This study highlights the risk of reusing cleaning solutions in dairies.}, }
@article {pmid31202277, year = {2019}, author = {Soverini, M and Turroni, S and Biagi, E and Brigidi, P and Candela, M and Rampelli, S}, title = {HumanMycobiomeScan: a new bioinformatics tool for the characterization of the fungal fraction in metagenomic samples.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {496}, doi = {10.1186/s12864-019-5883-y}, pmid = {31202277}, issn = {1471-2164}, abstract = {BACKGROUND: Modern metagenomic analysis of complex microbial communities produces large amounts of sequence data containing information on the microbiome in terms of bacterial, archaeal, viral and eukaryotic composition. The bioinformatics tools available are mainly devoted to profiling the bacterial and viral fractions and only a few software packages consider fungi. As the human fungal microbiome (human mycobiome) can play an important role in the onset and progression of diseases, a comprehensive description of host-microbiota interactions cannot ignore this component.<br><br>RESULTS: HumanMycobiomeScan is a bioinformatics tool for the taxonomic profiling of the mycobiome directly from raw data of next-generation sequencing. The tool uses hierarchical databases of fungi in order to unambiguously assign reads to fungal species more accurately and > 10,000 times faster than other comparable approaches. HumanMycobiomeScan was validated using in silico generated synthetic communities and then applied to metagenomic data, to characterize the intestinal fungal components in subjects adhering to different subsistence strategies.<br><br>CONCLUSIONS: Although blind to unknown species, HumanMycobiomeScan allows the characterization of the fungal fraction of complex microbial ecosystems with good performance in terms of sample denoising from reads belonging to other microorganisms. HumanMycobiomeScan is most appropriate for well-studied microbiomes, for which most of the fungal species have been fully sequenced. This released version is functionally implemented to work with human-associated microbiota samples. In combination with other microbial profiling tools, HumanMycobiomeScan is a frugal and efficient tool for comprehensive characterization of microbial ecosystems through shotgun metagenomics sequencing.}, }
@article {pmid31201518, year = {2019}, author = {Moisan, K and Cordovez, V and van de Zande, EM and Raaijmakers, JM and Dicke, M and Lucas-Barbosa, D}, title = {Volatiles of pathogenic and non-pathogenic soil-borne fungi affect plant development and resistance to insects.}, journal = {Oecologia}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00442-019-04433-w}, pmid = {31201518}, issn = {1432-1939}, abstract = {Plants are ubiquitously exposed to a wide diversity of (micro)organisms, including mutualists and antagonists. Prior to direct contact, plants can perceive microbial organic and inorganic volatile compounds (hereafter: volatiles) from a distance that, in turn, may affect plant development and resistance. To date, however, the specificity of plant responses to volatiles emitted by pathogenic and non-pathogenic fungi and the ecological consequences of such responses remain largely elusive. We investigated whether Arabidopsis thaliana plants can differentiate between volatiles of pathogenic and non-pathogenic soil-borne fungi. We profiled volatile organic compounds (VOCs) and measured CO2 emission of 11 fungi. We assessed the main effects of fungal volatiles on plant development and insect resistance. Despite distinct differences in VOC profiles between the pathogenic and non-pathogenic fungi, plants did not discriminate, based on plant phenotypic responses, between pathogenic and non-pathogenic fungi. Overall, plant growth was promoted and flowering was accelerated upon exposure to fungal volatiles, irrespectively of fungal CO2 emission levels. In addition, plants became significantly more susceptible to a generalist insect leaf-chewing herbivore upon exposure to the volatiles of some of the fungi, demonstrating that a prior fungal volatile exposure can negatively affect plant resistance. These data indicate that plant development and resistance can be modulated in response to exposure to fungal volatiles.}, }
@article {pmid31201356, year = {2019}, author = {Szafrański, SP and Kilian, M and Yang, I and Bei der Wieden, G and Winkel, A and Hegermann, J and Stiesch, M}, title = {Diversity patterns of bacteriophages infecting Aggregatibacter and Haemophilus species across clades and niches.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0450-8}, pmid = {31201356}, issn = {1751-7370}, abstract = {Aggregatibacter and Haemophilus species are relevant human commensals and opportunistic pathogens. Consequently, their bacteriophages may have significant impact on human microbial ecology and pathologies. Our aim was to reveal the prevalence and diversity of bacteriophages infecting Aggregatibacter and Haemophilus species that colonize the human body. Genome mining with comparative genomics, screening of clinical isolates, and profiling of metagenomes allowed characterization of 346 phages grouped in 52 clusters and 18 superclusters. Less than 10% of the identified phage clusters were represented by previously characterized phages. Prophage diversity patterns varied significantly for different phage types, host clades, and environmental niches. A more diverse phage community lysogenizes Haemophilus influenzae and Haemophilus parainfluenzae strains than Aggregatibacter actinomycetemcomitans and &quot;Haemophilus ducreyi&quot;. Co-infections occurred more often in &quot;H. ducreyi&quot;. Phages from Aggregatibacter actinomycetemcomitans preferably lysogenized strains of specific serotype. Prophage patterns shared by subspecies clades of different bacterial species suggest similar ecoevolutionary drivers. Changes in frequencies of DNA uptake signal sequences and guanine-cytosine content reflect phage-host long-term coevolution. Aggregatibacter and Haemophilus phages were prevalent at multiple oral sites. Together, these findings should help exploring the ecoevolutionary forces shaping virus-host interactions in the human microbiome. Putative lytic phages, especially phiKZ-like, may provide new therapeutic options.}, }
@article {pmid31195556, year = {1997}, author = {Giraffa, G and Carminati, D and Neviani, E}, title = {Enterococci Isolated from Dairy Products: A Review of Risks and Potential Technological Use.}, journal = {Journal of food protection}, volume = {60}, number = {6}, pages = {732-738}, doi = {10.4315/0362-028X-60.6.732}, pmid = {31195556}, issn = {1944-9097}, abstract = {Enterococci are ubiquitous bacteria which frequently occur in large numbers in dairy and other food products. Although they share a number of biotechnological traits (e.g., bacteriocin production, probiotic characteristics, usefulness in dairy technology), there is no consensus on whether enterococci pose a threat as foodborne pathogens, The potential pathogenicity of lactic acid bacteria (LAB), including enterococci, in human clinical infections and their association with endocarditis have recently become a matter of controversy, in spite of the fact that foods containing enterococci have a long history of safe use. This article provides literature data available on microbial ecology, biochemical properties, production of anti- Listeria bacteriocins, and potential pathogenic traits of enterococci isolated from different dairy products.}, }
@article {pmid31195956, year = {2019}, author = {Hirano, H and Takemoto, K}, title = {Difficulty in inferring microbial community structure based on co-occurrence network approaches.}, journal = {BMC bioinformatics}, volume = {20}, number = {1}, pages = {329}, doi = {10.1186/s12859-019-2915-1}, pmid = {31195956}, issn = {1471-2105}, support = {JP17H04703//Japan Society for the Promotion of Science/ ; }, abstract = {BACKGROUND: Co-occurrence networks-ecological associations between sampled populations of microbial communities inferred from taxonomic composition data obtained from high-throughput sequencing techniques-are widely used in microbial ecology. Several co-occurrence network methods have been proposed. Co-occurrence network methods only infer ecological associations and are often used to discuss species interactions. However, validity of this application of co-occurrence network methods is currently debated. In particular, they simply evaluate using parametric statistical models, even though microbial compositions are determined through population dynamics.<br><br>RESULTS: We comprehensively evaluated the validity of common methods for inferring microbial ecological networks through realistic simulations. We evaluated how correctly nine widely used methods describe interaction patterns in ecological communities. Contrary to previous studies, the performance of the co-occurrence network methods on compositional data was almost equal to or less than that of classical methods (e.g., Pearson's correlation). The methods described the interaction patterns in dense and/or heterogeneous networks rather inadequately. Co-occurrence network performance also depended upon interaction types; specifically, the interaction patterns in competitive communities were relatively accurately predicted while those in predator-prey (parasitic) communities were relatively inadequately predicted.<br><br>CONCLUSIONS: Our findings indicated that co-occurrence network approaches may be insufficient in interpreting species interactions in microbiome studies. However, the results do not diminish the importance of these approaches. Rather, they highlight the need for further careful evaluation of the validity of these much-used methods and the development of more suitable methods for inferring microbial ecological networks.}, }
@article {pmid31194939, year = {2019}, author = {Johnson, AJ and Vangay, P and Al-Ghalith, GA and Hillmann, BM and Ward, TL and Shields-Cutler, RR and Kim, AD and Shmagel, AK and Syed, AN and ,  and Walter, J and Menon, R and Koecher, K and Knights, D}, title = {Daily Sampling Reveals Personalized Diet-Microbiome Associations in Humans.}, journal = {Cell host &amp; microbe}, volume = {25}, number = {6}, pages = {789-802.e5}, doi = {10.1016/j.chom.2019.05.005}, pmid = {31194939}, issn = {1934-6069}, abstract = {Diet is a key determinant of human gut microbiome variation. However, the fine-scale relationships between daily food choices and human gut microbiome composition remain unexplored. Here, we used multivariate methods to integrate 24-h food records and fecal shotgun metagenomes from 34 healthy human subjects collected daily over 17 days. Microbiome composition depended on multiple days of dietary history and was more strongly associated with food choices than with conventional nutrient profiles, and daily microbial responses to diet were highly personalized. Data from two subjects consuming only meal replacement beverages suggest that a monotonous diet does not induce microbiome stability in humans, and instead, overall dietary diversity associates with microbiome stability. Our work provides key methodological insights for future diet-microbiome studies and suggests that food-based interventions seeking to modulate the gut microbiota may need to be tailored to the individual microbiome. Trial Registration: ClinicalTrials.gov: NCT03610477.}, }
@article {pmid31194515, year = {2019}, author = {Ali, M and Wang, Z and Salam, KW and Hari, AR and Pronk, M and van Loosdrecht, MCM and Saikaly, PE}, title = {Importance of Species Sorting and Immigration on the Bacterial Assembly of Different-Sized Aggregates in a Full-Scale Aerobic Granular Sludge Plant.}, journal = {Environmental science &amp; technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.8b07303}, pmid = {31194515}, issn = {1520-5851}, abstract = {In aerobic granular sludge (AGS) systems, different-sized microbial aggregates having different solids retention time (SRT) coexist in the same reactor compartment and are subjected to the same influent wastewater. Thus, the AGS system provides a unique ecosystem to study the importance of local (species sorting) and regional (immigration) processes in bacterial community assembly. The microbial communities of different-sized aggregates (flocs <0.2 mm, small granules (0.2-1.0 mm) and large granules >1.0 mm), influent wastewater, excess sludge and effluent of a full-scale AGS plant were characterized over a steady-state operation period of 6 months. Amplicon sequencing was integrated with mass balance to determine the SRT and net growth rate of operational taxonomic units (OTUs). We found strong evidence of species sorting as opposed to immigration, which was significantly higher at short SRT (i.e., flocs and small granules) than that at long SRT (large granules). Rare OTUs in wastewater belonging to putative functional groups responsible for nitrogen and phosphorus removal were progressively enriched with an increase in microbial aggregates size. In contrast, fecal- and sewage infrastructure-derived microbes progressively decreased in relative abundance with increase in microbial aggregate size. These findings highlight the importance of AGS as a unique model ecosystem to study fundamental microbial ecology concepts.}, }
@article {pmid31191599, year = {2019}, author = {Zhang, B and Xu, S and Xu, W and Chen, Q and Chen, Z and Yan, C and Fan, Y and Zhang, H and Liu, Q and Yang, J and Yang, J and Xiao, C and Xu, H and Ren, J}, title = {Leveraging Fecal Bacterial Survey Data to Predict Colorectal Tumors.}, journal = {Frontiers in genetics}, volume = {10}, number = {}, pages = {447}, doi = {10.3389/fgene.2019.00447}, pmid = {31191599}, issn = {1664-8021}, abstract = {Colorectal cancer (CRC) ranks second in cancer-associated mortality and third in the incidence worldwide. Most of CRC follow adenoma-carcinoma sequence, and have more than 90% chance of survival if diagnosed at early stage. But the recommended screening by colonoscopy is invasive, expensive, and poorly adhered to. Recently, several studies reported that the fecal bacteria might provide non-invasive biomarkers for CRC and precancerous tumors. Therefore, we collected and uniformly re-analyzed these published fecal 16S rDNA sequencing datasets to verify the association and identify biomarkers to classify and predict colorectal tumors by random forest method. A total of 1674 samples (330 CRC, 357 advanced adenoma, 141 adenoma, and 846 control) from 7 studies were analyzed in this study. By random effects model and fixed effects model, we observed significant differences in alpha-diversity and beta-diversity between individuals with CRC and the normal colon, but not between adenoma and the normal. We identified various bacterial genera with significant odds ratios for colorectal tumors at different stages. Through building random forest model with 10-fold cross-validation as well as new test datasets, we classified individuals with CRC, advanced adenoma, adenoma and normal colon. All approaches obtained comparable performance at entire OTU level, entire genus level, and the common genus level as measured using AUC. When combined all samples, the AUC of random forest model based on 12 common genera reached 0.846 for CRC, although the predication performed poorly for advance adenoma and adenoma.}, }
@article {pmid31191490, year = {2019}, author = {Chronopoulou, PM and Salonen, I and Bird, C and Reichart, GJ and Koho, KA}, title = {Metabarcoding Insights Into the Trophic Behavior and Identity of Intertidal Benthic Foraminifera.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1169}, doi = {10.3389/fmicb.2019.01169}, pmid = {31191490}, issn = {1664-302X}, abstract = {Foraminifera are ubiquitous marine protists with an important role in the benthic carbon cycle. However, morphological observations often fail to resolve their exact taxonomic placement and there is a lack of field studies on their particular trophic preferences. Here, we propose the application of metabarcoding as a tool for the elucidation of the in situ feeding behavior of benthic foraminifera, while also allowing the correct taxonomic assignment of the feeder, using the V9 region of the 18S (small subunit; SSU) rRNA gene. Living foraminiferal specimens were collected from two intertidal mudflats of the Wadden Sea and DNA was extracted from foraminiferal individuals and from the surrounding sediments. Molecular analysis allowed us to confirm that our foraminiferal specimens belong to three genetic types: Ammonia sp. T6, Elphidium sp. S5 and Haynesina sp. S16. Foraminiferal intracellular eukaryote communities reflected to an extent those of the surrounding sediments but at different relative abundances. Unlike sediment eukaryote communities, which were largely determined by the sampling site, foraminiferal intracellular eukaryote communities were driven by foraminiferal species, followed by sediment depth. Our data suggests that Ammonia sp. T6 can predate on metazoan classes, whereas Elphidium sp. S5 and Haynesina sp. S16 are more likely to ingest diatoms. These observations, alongside the use of metabarcoding in similar ecological studies, significantly contribute to our overall understanding of the ecological roles of these protists in intertidal benthic environments and their position and function in the benthic food webs.}, }
@article {pmid31189482, year = {2019}, author = {Bouslimani, A and da Silva, R and Kosciolek, T and Janssen, S and Callewaert, C and Amir, A and Dorrestein, K and Melnik, AV and Zaramela, LS and Kim, JN and Humphrey, G and Schwartz, T and Sanders, K and Brennan, C and Luzzatto-Knaan, T and Ackermann, G and McDonald, D and Zengler, K and Knight, R and Dorrestein, PC}, title = {The impact of skin care products on skin chemistry and microbiome dynamics.}, journal = {BMC biology}, volume = {17}, number = {1}, pages = {47}, doi = {10.1186/s12915-019-0660-6}, pmid = {31189482}, issn = {1741-7007}, support = {634402//Horizon 2020/ ; 2015-DN-BX-K047//National Institute of Justice/ ; AR071731//Foundation for the National Institutes of Health/ ; }, abstract = {BACKGROUND: Use of skin personal care products on a regular basis is nearly ubiquitous, but their effects on molecular and microbial diversity of the skin are unknown. We evaluated the impact of four beauty products (a facial lotion, a moisturizer, a foot powder, and a deodorant) on 11 volunteers over 9 weeks.<br><br>RESULTS: Mass spectrometry and 16S rRNA inventories of the skin revealed decreases in chemical as well as in bacterial and archaeal diversity on halting deodorant use. Specific compounds from beauty products used before the study remain detectable with half-lives of 0.5-1.9 weeks. The deodorant and foot powder increased molecular, bacterial, and archaeal diversity, while arm and face lotions had little effect on bacterial and archaeal but increased chemical diversity. Personal care product effects last for weeks and produce highly individualized responses, including alterations in steroid and pheromone levels and in bacterial and archaeal ecosystem structure and dynamics.<br><br>CONCLUSIONS: These findings may lead to next-generation precision beauty products and therapies for skin disorders.}, }
@article {pmid31186603, year = {2018}, author = {Saha, M and Goecke, F and Bhadury, P}, title = {Correction to: Minireview: algal natural compounds and extracts as antifoulants.}, journal = {Journal of applied phycology}, volume = {30}, number = {3}, pages = {1875}, doi = {10.1007/s10811-018-1424-3}, pmid = {31186603}, issn = {0921-8971}, abstract = {[This corrects the article DOI: 10.1007/s10811-017-1322-0.].}, }
@article {pmid31187884, year = {2019}, author = {Vissenaekens, H and Grootaert, C and Rajkovic, A and Van De Wiele, T and Calatayud, M}, title = {The response of five intestinal cell lines to anoxic conditions in vitro.}, journal = {Biology of the cell}, volume = {}, number = {}, pages = {}, doi = {10.1111/boc.201800076}, pmid = {31187884}, issn = {1768-322X}, abstract = {BACKGROUND INFORMATION: In vivo oxygen levels in tissues range from 1% to 15%, while, mechanistic cell culture studies employ an atmospheric oxygen level of 21% to grow cells. These oxygen concentrations are therefore not representative for conditions where the cell response is dependent on oxygen partial pressure. In pathological situation, such as (colon) cancer or chronic inflammation, tissue oxygenation is severely affected, and even under physiological conditions, a steep oxygen gradient is present in the large intestine, where epithelial cells co-exist with microbial species, resulting in almost anoxia at the midpoint of the lumen. In these situations, a better characterization of the essential cellular behavior under hypoxia or anoxia is required.<br><br>RESULTS: We have characterized the cellular response of commonly used cell cultures for the study of intestinal epithelial processes and colon cancer development (Caco-2, HT-29, SW480, HCT 116 and LoVo) under conventional normoxic conditions (21% O2) and in an anoxic (< 0.1% O2) environment generated in an anaerobic chamber. In general, anoxic conditions led to lower levels of oxidative stress, a reduction in GSH/GSSG ratio, the shift of the redox status to oxidized glutathione levels, reduced cell proliferation, decreased barrier function and higher glycolysis rates at the expense of oxidative respiration.<br><br>CONCLUSIONS: Continuous exposure to anoxic conditions, such as occurring at the host-microbe interface in the intestine, may create an adaptive metabolic cellular response of the cells.<br><br>SIGNIFICANCE: Considering adequate oxygen levels is essential for creating more physiologically relevant models for the study of host-microbe interactions and colon cancer development. This article is protected by copyright. All rights reserved.}, }
@article {pmid31187177, year = {2019}, author = {Johnke, J and Fraune, S and Bosch, TCG and Hentschel, U and Schulenburg, H}, title = {Bdellovibrio and Like Organisms Are Predictors of Microbiome Diversity in Distinct Host Groups.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01395-7}, pmid = {31187177}, issn = {1432-184X}, support = {CRC 1182, project A4//Deutsche Forschungsgemeinschaft (DE)/ ; CRC 1182, project B2//Deutsche Forschungsgemeinschaft (DE)/ ; CRC 1182, project B2//Deutsche Forschungsgemeinschaft (DE)/ ; CRC 1182, project A4//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Biodiversity is generally believed to be a main determinant of ecosystem functioning. This principle also applies to the microbiome and could consequently contribute to host health. According to ecological theory, communities are shaped by top predators whose direct and indirect interactions with community members cause stability and diversity. Bdellovibrio and like organisms (BALOs) are a neglected group of predatory bacteria that feed on Gram-negative bacteria and can thereby influence microbiome composition. We asked whether BALOs can predict biodiversity levels in microbiomes from distinct host groups and environments. We demonstrate that genetic signatures of BALOs are commonly found within the 16S rRNA reads from diverse host taxa. In many cases, their presence, abundance, and especially richness are positively correlated with overall microbiome diversity. Our findings suggest that BALOs can act as drivers of microbial alpha-diversity and should therefore be considered candidates for the restoration of microbiomes and the prevention of dysbiosis.}, }
@article {pmid31187139, year = {2019}, author = {Pacheco, AR and Segrè, D}, title = {A multidimensional perspective on microbial interactions.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnz125}, pmid = {31187139}, issn = {1574-6968}, abstract = {Beyond being simply positive or negative, beneficial or inhibitory, microbial interactions can involve a diverse set of mechanisms, dependencies, and dynamical properties. These more nuanced features have been described in great detail for some specific types of interactions, (e.g. pairwise metabolic cross-feeding, quorum sensing, or antibiotic killing), often with the use of quantitative measurements and insight derived from modeling. With a growing understanding of the composition and dynamics of complex microbial communities for human health and other applications, we face the challenge of integrating information about these different interactions into comprehensive quantitative frameworks. Here, we review literature on a wide set of microbial interactions, and explore the potential value of a formal categorization based on multidimensional vectors of attributes. We propose that such an encoding can facilitate systematic, direct comparisons of interaction mechanisms and dependencies, and we discuss the relevance of an atlas of interactions for future modeling and rational design efforts.}, }
@article {pmid31186361, year = {2019}, author = {Kehe, J and Kulesa, A and Ortiz, A and Ackerman, CM and Thakku, SG and Sellers, D and Kuehn, S and Gore, J and Friedman, J and Blainey, PC}, title = {Massively parallel screening of synthetic microbial communities.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {}, number = {}, pages = {}, doi = {10.1073/pnas.1900102116}, pmid = {31186361}, issn = {1091-6490}, abstract = {Microbial communities have numerous potential applications in biotechnology, agriculture, and medicine. Nevertheless, the limited accuracy with which we can predict interspecies interactions and environmental dependencies hinders efforts to rationally engineer beneficial consortia. Empirical screening is a complementary approach wherein synthetic communities are combinatorially constructed and assayed in high throughput. However, assembling many combinations of microbes is logistically complex and difficult to achieve on a timescale commensurate with microbial growth. Here, we introduce the kChip, a droplets-based platform that performs rapid, massively parallel, bottom-up construction and screening of synthetic microbial communities. We first show that the kChip enables phenotypic characterization of microbes across environmental conditions. Next, in a screen of ∼100,000 multispecies communities comprising up to 19 soil isolates, we identified sets that promote the growth of the model plant symbiont Herbaspirillum frisingense in a manner robust to carbon source variation and the presence of additional species. Broadly, kChip screening can identify multispecies consortia possessing any optically assayable function, including facilitation of biocontrol agents, suppression of pathogens, degradation of recalcitrant substrates, and robustness of these functions to perturbation, with many applications across basic and applied microbial ecology.}, }
@article {pmid31186282, year = {2019}, author = {Biancalani, T and Gore, J}, title = {Disentangling bacterial invasiveness from lethality in an experimental host-pathogen system.}, journal = {Molecular systems biology}, volume = {15}, number = {6}, pages = {e8707}, doi = {10.15252/msb.20188707}, pmid = {31186282}, issn = {1744-4292}, abstract = {Quantifying virulence remains a central problem in human health, pest control, disease ecology, and evolutionary biology. Bacterial virulence is typically quantified by the LT50 (i.e., the time taken to kill 50% of infected hosts); however, such an indicator cannot account for the full complexity of the infection process, such as distinguishing between the pathogen's ability to colonize versus kill the hosts. Indeed, the pathogen needs to breach the primary defenses in order to colonize, find a suitable environment to replicate, and finally express the virulence factors that cause disease. Here, we show that two virulence attributes, namely pathogen lethality and invasiveness, can be disentangled from the survival curves of a laboratory population of Caenorhabditis elegans nematodes exposed to three bacterial pathogens: Pseudomonas aeruginosa, Serratia marcescens, and Salmonella enterica We first show that the host population eventually experiences a constant mortality rate, which quantifies the lethality of the pathogen. We then show that the time necessary to reach this constant mortality rate regime depends on the pathogen growth rate and colonization rate, and thus determines the pathogen invasiveness. Our framework reveals that Serratia marcescens is particularly good at the initial colonization of the host, whereas Salmonella enterica is a poor colonizer yet just as lethal once established. Pseudomonas aeruginosa, on the other hand, is both a good colonizer and highly lethal after becoming established. The ability to quantitatively characterize the ability of different pathogens to perform each of these steps has implications for treatment and prevention of disease and for the evolution and ecology of pathogens.}, }
@article {pmid31180804, year = {2019}, author = {Welch, JLM and Dewhirst, FE and Borisy, GG}, title = {Biogeography of the Oral Microbiome: The Site-Specialist Hypothesis.}, journal = {Annual review of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1146/annurev-micro-090817-062503}, pmid = {31180804}, issn = {1545-3251}, abstract = {Microbial communities are complex and dynamic, composed of hundreds of taxa interacting across multiple spatial scales. Advances in sequencing and imaging technology have led to great strides in understanding both the composition and the spatial organization of these complex communities. In the human mouth, sequencing results indicate that distinct sites host microbial communities that not only are distinguishable but to a meaningful degree are composed of entirely different microbes. Imaging suggests that the spatial organization of these communities is also distinct. Together, the literature supports the idea that most oral microbes are site specialists. A clear understanding of microbiota structure at different sites in the mouth enables mechanistic studies, informs the generation of hypotheses, and strengthens the position of oral microbiology as a model system for microbial ecology in general. Expected final online publication date for the Annual Review of Microbiology Volume 73 is September 9, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.}, }
@article {pmid31178845, year = {2019}, author = {Berlanas, C and Berbegal, M and Elena, G and Laidani, M and Cibriain, JF and Sagües, A and Gramaje, D}, title = {The Fungal and Bacterial Rhizosphere Microbiome Associated With Grapevine Rootstock Genotypes in Mature and Young Vineyards.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1142}, doi = {10.3389/fmicb.2019.01142}, pmid = {31178845}, issn = {1664-302X}, abstract = {The microbiota colonizing the rhizosphere and the endorhizosphere contribute to plant growth, productivity, carbon sequestration, and phytoremediation. Several studies suggested that different plants types and even genotypes of the same plant species harbor partially different microbiomes. Here, we characterize the rhizosphere bacterial and fungal microbiota across five grapevine rootstock genotypes cultivated in the same soil at two vineyards and sampling dates over 2 years by 16S rRNA gene and ITS high-throughput amplicon sequencing. In addition, we use quantitative PCR (qPCR) approach to measure the relative abundance and dynamic changes of fungal pathogens associated with black-foot disease. The objectives were to (1) unravel the effects of rootstock genotype on microbial communities in the rhizosphere of grapevine and (2) to compare the relative abundances of sequence reads and DNA amount of black-foot disease pathogens. Host genetic control of the microbiome was evident in the rhizosphere of the mature vineyard. Microbiome composition also shifted as year of sampling, and fungal diversity varied with sampling moments. Linear discriminant analysis identified specific bacterial (i.e., Bacillus) and fungal (i.e., Glomus) taxa associated with grapevine rootstocks. Host genotype did not predict any summary metrics of rhizosphere α- and β-diversity in the young vineyard. Regarding black-foot associated pathogens, a significant correlation between sequencing reads and qPCR was observed. In conclusion, grapevine rootstock genotypes in the mature vineyard were associated with different rhizosphere microbiomes. The latter could also have been affected by age of the vineyard, soil properties or field management practices. A more comprehensive study is needed to decipher the cause of the rootstock microbiome selection and the mechanisms by which grapevines are able to shape their associated microbial community. Understanding the vast diversity of bacteria and fungi in the rhizosphere and the interactions between microbiota and grapevine will facilitate the development of future strategies for grapevine protection.}, }
@article {pmid31177395, year = {2019}, author = {Liu, H and Wu, M and Liu, J and Qu, Y and Gao, Y and Ren, A}, title = {Tripartite Interactions Between Endophytic Fungi, Arbuscular Mycorrhizal Fungi, and Leymus chinensis.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01394-8}, pmid = {31177395}, issn = {1432-184X}, support = {31570433//National Natural Science Foundation of China/ ; 2016YFC0500702//National Key Research and Development Program/ ; }, abstract = {Grasses often establish multiple simultaneous symbiotic associations with endophytic fungi and arbuscular mycorrhizal fungi (AMF). Many studies have examined pair-wise interactions between plants and endophytic fungi or between plants and AMF, overlooking the interplays among multiple endosymbionts and their combined impacts on hosts. Here, we examined both the way in which each symbiont affects the other symbionts and the tripartite interactions between leaf endophytic fungi, AMF, and Leymus chinensis. As for AMF, different species (Glomus etunicatum, GE; Glomus mosseae, GM; Glomus claroideum, GC; and Glomus intraradices, GI) and AMF richness (no AMF, single AMF taxa, double AMF mixtures, triple AMF mixtures, and all four together) were considered. Our results showed that significant interactions were observed between endophytes and AMF, with endophytes interacting antagonistically with GM but synergistically with GI. No definitive interactions were observed between the endophytes and GE or GC. Additionally, the concentration of endophytes in the leaf sheath was positively correlated with the concentration of AMF in the roots under low AMF richness. The shoot biomass of L. chinensis was positively related to both endophyte concentration and AMF concentration, with only endophytes contributing to shoot biomass more than AMF. Endophytes and AMF increased shoot growth by contributing to phosphorus uptake. The interactive effects of endophytes and AMF on host growth were affected by the identity of AMF species. The beneficial effect of the endophytes decreased in response to GM but increased in response to GI. However, no influences were observed with other GC and GE. In addition, endophyte presence can alter the response of host plants to AMF richness. When leaf endophytes were absent, shoot biomass increased with higher AMF richness, only the influence of AMF species identity outweighed that of AMF richness. However, when leaf endophytes were present, no significant association was observed between AMF richness and shoot biomass. AMF species identity rather than AMF richness promoted shoot growth. The results of this study demonstrate that the outcomes of interspecific symbiotic interactions are very complex and vary with partner identity such that the effects of simultaneous symbioses cannot be generalized and highlight the need for studies to evaluate fitness response of all three species, as the interactive effects may not be the same for each partner.}, }
@article {pmid31176264, year = {2019}, author = {Patel, R and Kunjadia, P and Koringa, P and Joshi, C and Kunjadiya, A}, title = {Microbiological profiles in clinical and subclinical cases of mastitis in milking Jafarabadi buffalo.}, journal = {Research in veterinary science}, volume = {125}, number = {}, pages = {94-99}, doi = {10.1016/j.rvsc.2019.05.012}, pmid = {31176264}, issn = {1532-2661}, abstract = {Mastitis is one of the important diseases affecting the dairy industry across the globe. Identification of bacterial pathogens associated with mastitis becomes essential in order to understand the etiology of disease which in turn will help to new strategies to control it. Microbial diversity analysis using pyrosequencing is widely studied for mastitis pathogens in dairy cows. However it is unexplored in case of buffalo. In the present study 16SrDNA gene pyrosequencing was used to characterize microbiota associated with clinical and subclinical mastitis in 28 Jafarabadi buffalo. The obtained sequencing data were analyzed by Quantitative Insights into Microbial Ecology (QIIME) and statistical analysis was done using Paleontological Statistics (PAST). Pyrosequencing produced 47.3 million base pairs reads. Phylogenetic profiles using ribosomal database revealed differences in abundance of Staphylococcus (25.95%, 10.09% and 0.03%), Enterococcus (10.80%, 8.72% and 0.36%), Escherichia (8.88%, 0.38% and 0.00%), Streptococcus (3.97%, 0.42% and 0.00%), Lactococcus (3.73%, 23.96% and 0.01%), and Ralstonia (0.54%, 12.72% and 0.00%), genera in clinical, subclinical and healthy samples, respectively. Different microbial profiles in clinical and subclinical mastitis in buffalo suggest the composition of bacteria in the milk is more diverse and complex hence single therapeutic regimes cannot be applied.}, }
@article {pmid31173081, year = {2019}, author = {Roodt, D and Li, Z and Van de Peer, Y and Mizrachi, E}, title = {Loss of wood formation genes in monocot genomes.}, journal = {Genome biology and evolution}, volume = {}, number = {}, pages = {}, doi = {10.1093/gbe/evz115}, pmid = {31173081}, issn = {1759-6653}, abstract = {Woodiness (secondary xylem derived from vascular cambium) has been gained and lost multiple times in the angiosperms, but has been lost ancestrally in all monocots. Here, we investigate the conservation of genes involved in xylogenesis in fully sequenced angiosperm genomes, hypothesising that monocots have lost some essential orthologs involved in this process. We analysed the conservation of genes preferentially expressed in the developing secondary xylem of two eudicot trees in the sequenced genomes of 26 eudicot and seven monocot species, and the early-diverging angiosperm Amborella trichopoda. We also reconstructed a regulatory model of early vascular cambial cell identity and differentiation and investigated the conservation of orthologs across the angiosperms. Additionally, we analysed the genome of the aquatic seagrass Zostera marina for additional losses of genes otherwise essential to, especially, secondary cell wall formation. Despite almost complete conservation of orthology within the early cambial differentiation gene network, we show a clear pattern of loss of genes preferentially expressed in secondary xylem in the monocots that are highly conserved across eudicot species. Our study provides candidate genes that may have led to the loss of vascular cambium in the monocots, and, by comparing terrestrial angiosperms to an aquatic monocot, highlights genes essential to vasculature on land.}, }
@article {pmid31171824, year = {2019}, author = {Verspecht, T and Rodriguez Herrero, E and Khodaparast, L and Khodaparast, L and Boon, N and Bernaerts, K and Quirynen, M and Teughels, W}, title = {Development of antiseptic adaptation and cross-adapatation in selected oral pathogens in vitro.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {8326}, doi = {10.1038/s41598-019-44822-y}, pmid = {31171824}, issn = {2045-2322}, support = {C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/17/086//KU Leuven (Katholieke Universiteit Leuven)/ ; }, abstract = {There is evidence that pathogenic bacteria can adapt to antiseptics upon repeated exposure. More alarming is the concomitant increase in antibiotic resistance that has been described for some pathogens. Unfortunately, effects of adaptation and cross-adaptation are hardly known for oral pathogens, which are very frequently exposed to antiseptics. Therefore, this study aimed to determine the in vitro increase in minimum inhibitory concentrations (MICs) in oral pathogens after repeated exposure to chlorhexidine or cetylpyridinium chloride, to examine if (cross-)adaptation to antiseptics/antibiotics occurs, if (cross-)adaptation is reversible and what the potential underlying mechanisms are. When the pathogens were exposed to antiseptics, their MICs significantly increased. This increase was in general at least partially conserved after regrowth without antiseptics. Some of the adapted species also showed cross-adaptation, as shown by increased MICs of antibiotics and the other antiseptic. In most antiseptic-adapted bacteria, cell-surface hydrophobicity was increased and mass-spectrometry analysis revealed changes in expression of proteins involved in a wide range of functional domains. These in vitro data shows the adaptation and cross-adaptation of oral pathogens to antiseptics and antibiotics. This was related to changes in cell surface hydrophobicity and in expression of proteins involved in membrane transport, virulence, oxidative stress protection and metabolism.}, }
@article {pmid31171429, year = {2019}, author = {Raskin, L and Nielsen, PH}, title = {Editorial overview: Integrating biotechnology and microbial ecology in urban water infrastructure through a microbiome continuum viewpoint.}, journal = {Current opinion in biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.copbio.2019.05.001}, pmid = {31171429}, issn = {1879-0429}, }
@article {pmid31167950, year = {2019}, author = {Ghashghavi, M and Belova, SE and Bodelier, PLE and Dedysh, SN and Kox, MAR and Speth, DR and Frenzel, P and Jetten, MSM and Lücker, S and Lüke, C}, title = {Methylotetracoccus oryzae Strain C50C1 Is a Novel Type Ib Gammaproteobacterial Methanotroph Adapted to Freshwater Environments.}, journal = {mSphere}, volume = {4}, number = {3}, pages = {}, doi = {10.1128/mSphere.00631-18}, pmid = {31167950}, issn = {2379-5042}, abstract = {Methane-oxidizing microorganisms perform an important role in reducing emissions of the greenhouse gas methane to the atmosphere. To date, known bacterial methanotrophs belong to the Proteobacteria, Verrucomicrobia, and NC10 phyla. Within the Proteobacteria phylum, they can be divided into type Ia, type Ib, and type II methanotrophs. Type Ia and type II are well represented by isolates. Contrastingly, the vast majority of type Ib methanotrophs have not been able to be cultivated so far. Here, we compared the distributions of type Ib lineages in different environments. Whereas the cultivated type Ib methanotrophs (Methylococcus and Methylocaldum) are found in landfill and upland soils, lineages that are not represented by isolates are mostly dominant in freshwater environments, such as paddy fields and lake sediments. Thus, we observed a clear niche differentiation within type Ib methanotrophs. Our subsequent isolation attempts resulted in obtaining a pure culture of a novel type Ib methanotroph, tentatively named &quot;Methylotetracoccus oryzae&quot; C50C1. Strain C50C1 was further characterized to be an obligate methanotroph, containing C16:1ω9c as the major membrane phospholipid fatty acid, which has not been found in other methanotrophs. Genome analysis of strain C50C1 showed the presence of two pmoCAB operon copies and XoxF5-type methanol dehydrogenase in addition to MxaFI. The genome also contained genes involved in nitrogen and sulfur cycling, but it remains to be demonstrated if and how these help this type Ib methanotroph to adapt to fluctuating environmental conditions in freshwater ecosystems.IMPORTANCE Most of the methane produced on our planet gets naturally oxidized by a group of methanotrophic microorganisms before it reaches the atmosphere. These microorganisms are able to oxidize methane, both aerobically and anaerobically, and use it as their sole energy source. Although methanotrophs have been studied for more than a century, there are still many unknown and uncultivated groups prevalent in various ecosystems. This study focused on the diversity and adaptation of aerobic methane-oxidizing bacteria in different environments by comparing their phenotypic and genotypic properties. We used lab-scale microcosms to create a countergradient of oxygen and methane for preenrichment, followed by classical isolation techniques to obtain methane-oxidizing bacteria from a freshwater environment. This resulted in the discovery and isolation of a novel methanotroph with interesting physiological and genomic properties that could possibly make this bacterium able to cope with fluctuating environmental conditions.}, }
@article {pmid31166992, year = {2019}, author = {Weinroth, MD and Britton, BC and McCullough, KR and Martin, JN and Geornaras, I and Knight, R and Belk, KE and Metcalf, JL}, title = {Ground beef microbiome changes with antimicrobial decontamination interventions and product storage.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0217947}, doi = {10.1371/journal.pone.0217947}, pmid = {31166992}, issn = {1932-6203}, abstract = {Ground beef makes up more than half of the beef consumed in the U.S. market. Although numerous studies have been conducted on microbial safety and shelf life of ground beef limited work has been done using a culture-independent approach. While past studies have allowed for the evaluation of a few organisms of interest, there is limited work on the microbial community associated with fresh ground beef. In order to have a more complete picture of the microbial ecology of the product, a culture-independent approach utilizing 16S rRNA gene amplicon sequencing was used. The objectives of this study were to characterize the fresh ground beef microbiome and the effect that antimicrobial interventions and antioxidants, applied to beef trim before grinding, and product storage have on community composition using 16S rRNA gene amplicon sequencing. Beef trimmings were treated with antimicrobials and an antioxidant. Samples were ground, loafed, and overwrapped before being packaged in modified-atmosphere packaging. Samples were in dark storage for 21 days followed by five days in retail display. Periodically during storage, samples were collected for microbiological analysis and DNA isolation. Due to low microbial biomass, only 52 of 210 samples were included in the final analysis. These samples represented two antimicrobial treatments (peroxyacetic acid, and a sulfuric acid and sodium sulfate blend) and a control, from day-15 of dark storage and day-5 of retail display. As sample age increased, so did the number of raw reads (P < 0.001) and aerobic plate counts (P < 0.001), which were correlated (r = 0.94, P = 0.017). Across all samples, lactic acid bacteria were most abundant followed by Enterobacteriaceae; several rare taxa were also identified (namely Geobacillus, Thermus, and Sporosarcina). Antimicrobial treatment altered the bacterial alpha (P < 0.001) and beta (P = 0.001) diversity, while storage day altered alpha (P = 0.001) diversity. Enterobacteriaceae relative abundance differed (P < 0.05) among treatments and was highest in control samples. In addition to confirming previously described dominant microbial differences in culture-dependent results, these data identified genera not typically associated with ground beef and allowed for study of shifts in the entire microbiome and not just a subset of indicator organisms.}, }
@article {pmid31166650, year = {2019}, author = {Maaroufi, NI and Nordin, A and Palmqvist, K and Hasselquist, NJ and Forsmark, B and Rosenstock, NP and Wallander, H and Gundale, MJ}, title = {Anthropogenic nitrogen enrichment enhances soil carbon accumulation by impacting saprotrophs rather than ectomycorrhizal fungal activity.}, journal = {Global change biology}, volume = {}, number = {}, pages = {}, doi = {10.1111/gcb.14722}, pmid = {31166650}, issn = {1365-2486}, abstract = {There is evidence that anthropogenic nitrogen (N) deposition enhances carbon (C) sequestration in boreal forest soils. However, it is unclear how free-living saprotrophs (bacteria and fungi, SAP) and ectomycorrhizal (EM) fungi responses to N addition impact soil C dynamics. Our aim was to investigate how SAP and EM communities are impacted by N enrichment and to estimate whether these changes influence decay of litter and humus. We conducted a long-term experiment in northern Sweden, maintained since 2004, consisting of ambient, low N additions (0, 3, 6 and 12 kg N ha-1 yr-1) simulating current N deposition rates in the boreal region, as well as a high N addition (50 kg N ha-1 yr-1). Our data showed that long-term N enrichment impeded mass loss of litter, but not of humus, and only in response to the highest N addition treatment. Further, our data showed that EM fungi reduced the mass of N and P in both substrates during the incubation period compared to when only SAP organisms were present. Low N additions had no effect on microbial community structure, while the high N addition decreased fungal and bacterial biomasses and altered EM fungi and SAP community composition. Actinomycetes were the only bacterial SAP to show increased biomass in response to the highest N addition. These results provide a mechanistic understanding of how anthropogenic N enrichment can influence soil C accumulation rates and suggest that current N deposition rates in the boreal region (≤ 12 kg N ha-1 yr-1) are likely to have a minor impact on the soil microbial community and the decomposition of humus and litter. This article is protected by copyright. All rights reserved.}, }
@article {pmid31165188, year = {2019}, author = {Li, Y and Guo, Q and He, F and Li, Y and Xue, Q and Lai, H}, title = {Biocontrol of Root Diseases and Growth Promotion of the Tuberous Plant Aconitum carmichaelii Induced by Actinomycetes Are Related to Shifts in the Rhizosphere Microbiota.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01388-6}, pmid = {31165188}, issn = {1432-184X}, support = {31600407//Youth Fund of the National Natural Science Foundation of China/ ; Z109021616//Fundamental Research Funds for the Central Universities of China/ ; 2012BAD14B11//National Key Technology R&amp;D Program of China/ ; }, abstract = {Soil Actinomycetes have been used as biocontrol agents against soil-borne plant diseases, yet little is known about their effects on the structure of the rhizosphere microbiota and the long-term effects on crop yield and disease intensity after the application of Actinomycetes is stopped. Here, we conducted 3-year plot experiments to investigate the roles of two Actinomycetes strains (Streptomyces pactum Act12 and Streptomyces rochei D74) in the biocontrol of soil-borne root diseases and growth promotion of monkhood (Aconitum carmichaelii). We also examined their long-term effects after soil application of a mixed Actinomycetes preparation (spore powder) was completed. High-throughput sequencing was used to analyze shifts in the rhizosphere microbiota. The antifungal activity and root colonization ability of the two Actinomycetes were also tested. Disease severity of southern blight and root rot decreased following application of the Actinomycetes preparation, whereas biomass yield of tubers increased compared with the control group. Significant effects of disease control and plant growth promotion were also observed after application was stopped. The Actinomycetes preparation induced marked increases in the abundance of beneficial microbes and decreases in the abundance of harmful microbes in rhizosphere soil. Adding cell-free culture filtrates of both strains Act12 and D74 inhibited the growth of fungal pathogens capable of causing southern blight (Sclerotium rolfsii) and root rot (Fusarium oxysporum) in A. carmichaelii. A GFP-labeled strain was used to show that D74 can colonize roots of A. carmichaelii. In conclusion, a preparation of two Actinomycetes plays a role in the biocontrol of root diseases and growth promotion of A. carmichaelii by inhibiting pathogen growth and shaping the rhizosphere microbiota.}, }
@article {pmid31165187, year = {2019}, author = {Kruger, A}, title = {Functional Redundancy of Batrachochytrium dendrobatidis Inhibition in Bacterial Communities Isolated from Lithobates clamitans Skin.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01387-7}, pmid = {31165187}, issn = {1432-184X}, abstract = {The cutaneous microbial community can influence the health of amphibians exposed to Batrachochytrium dendrobatidis (Bd), a fungal pathogen that has contributed to recent amphibian declines. Resistance to Bd in amphibian populations is correlated with the presence of anti-Bd cutaneous microbes, which confer disease resistance by inhibiting Bd growth. I aimed to determine if green frogs (Lithobates clamitans), an abundant and widely distributed species in New Jersey, harbored bacteria that inhibit Bd and whether the presence and identity of these microbes varied among sites. I used in vitro challenge assays to determine if bacteria isolated from green frog skin could inhibit or enhance the growth of Bd. I found that green frogs at all sites harbored anti-Bd bacteria. However, there were differences in Bd inhibition capabilities among bacterial isolates identified as the same operational taxonomic unit (OTU), lending support to the idea that phylogenetic relatedness does not always predict Bd inhibition status. Additionally, anti-Bd bacterial richness did not vary by site, but the composition of anti-Bd bacterial taxa was distinct at each site. This suggests that there is functional redundancy of Bd inhibition across unique communities of anti-Bd symbionts found on frogs at different sites. These findings highlight the need to better elucidate the structure-function relationship of microbiomes and their role in disease resistance.}, }
@article {pmid31164870, year = {2019}, author = {Guarcello, R and Gaglio, R and Todaro, A and Alfonzo, A and Schicchi, R and Cirlincione, F and Moschetti, G and Francesca, N}, title = {Insights Into the Cultivable Microbial Ecology of &quot;Manna&quot; Ash Products Extracted From Fraxinus angustifolia (Oleaceae) Trees in Sicily, Italy.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {984}, doi = {10.3389/fmicb.2019.00984}, pmid = {31164870}, issn = {1664-302X}, abstract = {Microbial communities characterizing a specific food matrix, generally, strongly contribute to both its composition, and properties for food applications. To our knowledge, this is the first study to investigate the cultivable microbial ecology of Sicilian &quot;Manna&quot; ash products in order to acquire new information on the hygienic quality, shelf-life and potential application of this traditional food. To this purpose, several manna samples belonging to different commercial categories were collected and subjected to the analysis of bacteria, yeasts, and filamentous fungi. Furthermore, an investigation of the sugar content and physicochemical parameters was performed. The results of our study followed the trend generally reported for other sugary foods. Conversely, as regards microbiological analyses, in the present study, the presence of microorganisms at high levels confirmed their survival in stressing conditions characterizing this food matrix in a viable and cultivable form. Most species were osmophilic, endophytic bacteria, antagonistic of fungi pathogen of plants. Yeasts were the most abundant microbial populations and a total of six species were identified: Candida aaseri, Candida lactis-condensi, Citeromyces matritensis, Lachancea thermotolerans, Saccharomyces cerevisiae, and Zygosaccharomyces bailii. Filamentous fungi included five genera, which were considered common contaminants of honey and of other foods due to their xerophilic characteristics. Interestingly, our results suggest that the strains of L. thermotolerans isolated in this study might be evaluated for their potential to act as starters either singly or in multi-combination for food applications.}, }
@article {pmid31164404, year = {2019}, author = {Bik, HM}, title = {Microbial Metazoa Are Microbes Too.}, journal = {mSystems}, volume = {4}, number = {3}, pages = {}, doi = {10.1128/mSystems.00109-19}, pmid = {31164404}, issn = {2379-5077}, abstract = {Microbial metazoa inhabit a certain &quot;Goldilocks zone,&quot; where conditions are just right for the continued ignorance of these taxa. These microscopic animal species have body sizes of <1 mm and include diverse groups such as nematodes, tardigrades, kinorhynchs, loriciferans, and platyhelminths. The majority of species are too large to be considered in single-cell genomics approaches, yet too small to be wrapped into international genome sequencing initiatives. Other microbial eukaryote groups (namely the fungal and protist communities) have gained significant momentum in recent years, driven by a strong community of researchers united behind a common goal of culturing and sequencing new representatives. However, due to historical factors and difficult taxonomy, persistent research silos still exist for most microbial metazoan groups, and public molecular databases remain sparsely populated. Here, I argue that small metazoa should be embraced as a key component of microbial ecology studies, promoting a holistic and cutting-edge view of natural ecosystems.}, }
@article {pmid31163430, year = {2019}, author = {Philip, N and Leishman, SJ and Bandara, HMHN and Walsh, LJ}, title = {Casein Phosphopeptide-Amorphous Calcium Phosphate Attenuates Virulence and Modulates Microbial Ecology of Saliva-Derived Polymicrobial Biofilms.}, journal = {Caries research}, volume = {}, number = {}, pages = {1-7}, doi = {10.1159/000499869}, pmid = {31163430}, issn = {1421-976X}, abstract = {BACKGROUND: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) acts as a salivary biomimetic that provides bioavailable calcium and phosphate ions to augment fluoride-mediated remineralisation of early caries lesions. However, there are indications that it may also have beneficial ecological effects on the oral microbiome.<br><br>OBJECTIVE: This in vitro study investigated whether CPP-ACP could influence microbial counts, acidogenicity, and the relative abundance of specific caries- and health-associated bacterial -species in polymicrobial biofilms.<br><br>METHODS: Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated every 12 h with 2% CPP-ACP or vehicle control. Colony forming units (CFUs) and acidogenicity were estimated from the treated biofilms. Microbial ecological effects of CPP-ACP were assessed based on the relative abundance of 14 specific caries- and health-associated -bacterial species using a real-time quantitative PCR assay. -Results: CPP-ACP-treated biofilms showed relatively modest, but significant, reductions in microbial CFUs (21% reduction, p = 0.008) and acidogenicity (33% reduction, p < 0.001), compared to the control-treated biofilms. The CPP-ACP treated biofilms also exhibited significantly lower bacterial loads of cariogenic Scardovia wiggsiae (fold change 0.017, p < 0.001) and Prevotella denticola(fold change 0.005, p < 0.001), and higher bacterial loads of commensal Streptococcus sanguinis(fold change 30.22, p < 0.001), S. mitis/oralis(fold change 9.66, p = 0.012), and S. salivarius/thermophilus(fold change 89.35, p < 0.001) than the control-treated biofilms.<br><br>CONCLUSIONS: The results indicate that CPP-ACP has virulence-attenuating attributes that can influence a beneficial microbial ecological change in the biofilm.}, }
@article {pmid31163257, year = {2019}, author = {Momper, L and Hu, E and Moore, KR and Skoog, EJ and Tyler, M and Evans, AJ and Bosak, T}, title = {Metabolic versatility in a modern lineage of cyanobacteria from terrestrial hot springs.}, journal = {Free radical biology &amp; medicine}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.freeradbiomed.2019.05.036}, pmid = {31163257}, issn = {1873-4596}, abstract = {The extent of oxygenated environments on the early Earth was much lower than today, and cyanobacteria were critical players in Earth's shift from widespread anoxia to oxygenated surface environments. Extant cyanobacteria that aggregate into cones, tufts and ridges are used to understand the long record of photosynthesis and microbe-mineral interactions during times when oxygen was much lower, i.e., the Archean and the Proterozoic. To better understand the metabolic versatility and physiological properties of these organisms, we examined publicly available genomes of cyanobacteria from modern terrestrial hydrothermal systems and a newly sequenced genome of a cyanobacterium isolated from conical and ridged microbialites that grow in occasionally sulfidic hydrothermal springs in Yellowstone National Park, USA. Phylogenomic analyses reveal that cyanobacteria from globally distributed terrestrial and shallow marine hydrothermal systems form a monophyletic clade within the Cyanobacteria phylum. Comparative genomics of this clade reveals the genetic capacity for oxygenic photosynthesis that uses photosystems I and II, and anoxygenic photosynthesis that uses a putative sulfide quinone reductase to oxidize sulfide and bypass photosystem II. Surprisingly large proportions of the newly sequenced genome from Yellowstone National Park are also dedicated to secondary metabolite production (15.1-15.6%), of which ∼6% can be attributed to antibiotic production and resistance genes. All this may be advantageous to benthic, mat-forming photosynthesizers that have to compete for light and nutrients in sporadically or permanently sulfidic environments, and may have also improved the tolerance of ancient counterparts of these cyanobacteria to sulfidic conditions in benthic communities that colonized the coastal margins in the Archean and the Proterozoic.}, }
@article {pmid31162610, year = {2019}, author = {Etienne-Mesmin, L and Chassaing, B and Desvaux, M and De Paepe, K and Gresse, R and Sauvaitre, T and Forano, E and Van de Wiele, T and Schüller, S and Juge, N and Blanquet-Diot, S}, title = {Experimental models to study intestinal microbes-mucus interactions in health and disease.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuz013}, pmid = {31162610}, issn = {1574-6976}, abstract = {A close symbiotic relationship exists between the intestinal microbiota and its host. A critical component of gut homeostasis is the presence of a mucus layer covering the gastrointestinal tract. Mucus is a viscoelastic gel at the interface between the luminal content and the host tissue that provides a habitat to the gut microbiota and protects the intestinal epithelium. The review starts by setting up the biological context underpinning the need for experimental models to study gut bacteria-mucus interactions in the digestive environment. We provide an overview of the structure and function of intestinal mucus and mucins, their interactions with intestinal bacteria (including commensal, probiotics and pathogenic microorganisms) and their role in modulating health and disease states. We then describe the characteristics and potentials of experimental models currently available to study the mechanisms underpinning the interaction of mucus with gut microbes, including in vitro, ex vivo and in vivo models. We then discuss the limitations and challenges facing this field of research.}, }
@article {pmid31161957, year = {2019}, author = {Ilgrande, C and Mastroleo, F and Christiaens, MER and Lindeboom, REF and Prat, D and Van Hoey, O and Ambrozova, I and Coninx, I and Heylen, W and Pommerening-Roser, A and Spieck, E and Boon, N and Vlaeminck, SE and Leys, N and Clauwaert, P}, title = {Reactivation of Microbial Strains and Synthetic Communities After a Spaceflight to the International Space Station: Corroborating the Feasibility of Essential Conversions in the MELiSSA Loop.}, journal = {Astrobiology}, volume = {}, number = {}, pages = {}, doi = {10.1089/ast.2018.1973}, pmid = {31161957}, issn = {1557-8070}, abstract = {To sustain human deep space exploration or extra-terrestrial settlements where no resupply from the Earth or other planets is possible, technologies for in situ food production, water, air, and waste recovery need to be developed. The Micro-Ecological Life Support System Alternative (MELiSSA) is such a Regenerative Life Support System (RLSS) and it builds on several bacterial bioprocesses. However, alterations in gravity, temperature, and radiation associated with the space environment can affect survival and functionality of the microorganisms. In this study, representative strains of different carbon and nitrogen metabolisms with application in the MELiSSA were selected for launch and Low Earth Orbit (LEO) exposure. An edible photoautotrophic strain (Arthrospira sp. PCC 8005), a photoheterotrophic strain (Rhodospirillum rubrum S1H), a ureolytic heterotrophic strain (Cupriavidus pinatubonensis 1245), and combinations of C. pinatubonensis 1245 and autotrophic ammonia and nitrite oxidizing strains (Nitrosomonas europaea ATCC19718, Nitrosomonas ureae Nm10, and Nitrobacter winogradskyi Nb255) were sent to the International Space Station (ISS) for 7 days. There, the samples were exposed to 2.8 mGy, a dose 140 times higher than on the Earth, and a temperature of 22°C ± 1°C. On return to the Earth, the cultures were reactivated and their growth and activity were compared with terrestrial controls stored under refrigerated (5°C ± 2°C) or room temperature (22°C ± 1°C and 21°C ± 0°C) conditions. Overall, no difference was observed between terrestrial and ISS samples. Most cultures presented lower cell viability after the test, regardless of the type of exposure, indicating a harsher effect of the storage and sample preparation than the spaceflight itself. Postmission analysis revealed the successful survival and proliferation of all cultures except for Arthrospira, which suffered from the premission depressurization test. These observations validate the possibility of launching, storing, and reactivating bacteria with essential functionalities for microbial bioprocesses in RLSS.}, }
@article {pmid31161232, year = {2019}, author = {Mojica, KDA and Carlson, CA and Behrenfeld, MJ}, title = {Regulation of Low and High Nucleic Acid Fluorescent Heterotrophic Prokaryote Subpopulations and Links to Viral-Induced Mortality Within Natural Prokaryote-Virus Communities.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01393-9}, pmid = {31161232}, issn = {1432-184X}, support = {NNX15AF30G//National Aeronautics and Space Administration/ ; 1537943//National Science Foundation/ ; }, abstract = {Flow cytometric analysis of marine prokaryotes routinely reveals two distinct clusters of heterotrophic cells referred to as high nucleic acid fluorescent (HNA) and low nucleic acid fluorescent (LNA) populations. Evidence suggests that these may represent physiologically and ecologically distinct prokaryote populations. According to the &quot;kill the winner&quot; hypothesis, viral lysis reduces the efficiency of the microbial loop by decreasing the biomass and activity of the most abundant and active members of a population (i.e., competition specialist). Thus, viral-induced mortality may vary according to the physiology of HNA and LNA cells, with implications for the marine carbon cycle. Here, the abundance and production of heterotrophic prokaryotic populations were assessed in the North Atlantic during two phases of the annual plankton cycle and related to bottom-up (i.e., organic carbon variability) and top-down processes (i.e., viral abundance and lytic production). Our results demonstrate that the relative abundance of HNA and LNA heterotrophic cells and heterotrophic prokaryote production vary according to organic carbon variability in the water column, which can be strongly influenced by the physical eddy field (i.e., type of eddy: cyclonic, anticyclonic, or no eddy). In addition, the abundance and lytic production of virus subpopulations were correlated with the cellular production and abundance of heterotrophic HNA and LNA prokaryote communities. Our data suggest group- and activity-specific linkages between hosts and viruses (i.e., HNA-V1 and LNA-V2). Specifically, V1 had a greater contribution to total viral production (i.e., 2.6-fold higher than V2 viruses), similar to their putative host. Finally, we explore potential implications of group- and activity-specific linkages between host and virus groups on the flux of carbon through the microbial food web.}, }
@article {pmid31159875, year = {2019}, author = {Wright, RJ and Gibson, MI and Christie-Oleza, JA}, title = {Understanding microbial community dynamics to improve optimal microbiome selection.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {85}, doi = {10.1186/s40168-019-0702-x}, pmid = {31159875}, issn = {2049-2618}, support = {NE/K009044/1//Natural Environment Research Council/ ; BB/M01116X/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; 638631//European Research Council/International ; }, abstract = {BACKGROUND: Artificial selection of microbial communities that perform better at a desired process has seduced scientists for over a decade, but the method has not been systematically optimised nor the mechanisms behind its success, or failure, determined. Microbial communities are highly dynamic and, hence, go through distinct and rapid stages of community succession, but the consequent effect this may have on artificially selected communities is unknown.<br><br>RESULTS: Using chitin as a case study, we successfully selected for microbial communities with enhanced chitinase activities but found that continuous optimisation of incubation times between selective transfers was of utmost importance. The analysis of the community composition over the entire selection process revealed fundamental aspects in microbial ecology: when incubation times between transfers were optimal, the system was dominated by Gammaproteobacteria (i.e. main bearers of chitinase enzymes and drivers of chitin degradation), before being succeeded by cheating, cross-feeding and grazing organisms.<br><br>CONCLUSIONS: The selection of microbiomes to enhance a desired process is widely used, though the success of artificially selecting microbial communities appears to require optimal incubation times in order to avoid the loss of the desired trait as a consequence of an inevitable community succession. A comprehensive understanding of microbial community dynamics will improve the success of future community selection studies.}, }
@article {pmid31156569, year = {2019}, author = {Joyner, JL and Kerwin, J and Deeb, M and Lozefski, G and Prithiviraj, B and Paltseva, A and McLaughlin, J and Groffman, P and Cheng, Z and Muth, TR}, title = {Green Infrastructure Design Influences Communities of Urban Soil Bacteria.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {982}, doi = {10.3389/fmicb.2019.00982}, pmid = {31156569}, issn = {1664-302X}, abstract = {The importance of natural ecosystem processes is often overlooked in urban areas. Green Infrastructure (GI) features have been constructed in urban areas as elements to capture and treat excess urban runoff while providing a range of ancillary benefits, e.g., ecosystem processes mediated by microorganisms that improve air and water quality, in addition to the associations with plant and tree rhizospheres. The objective of this study was to characterize the bacterial community and diversity in engineered soils (Technosols) of five types of GI in New York City; vegetated swales, right of way bioswales (ROWB; including street-side infiltration systems and enhanced tree pits), and an urban forest. The design of ROWB GI features directly connects with the road to manage street runoff, which can increase the Technosol saturation and exposure to urban contaminants washed from the street and carried into the GI feature. This GI design specifically accommodates dramatic pulses of water that influence the bacterial community composition and diversity through the selective pressure of contaminants or by disturbance. The ROWB had the highest biodiversity, but no significant correlation with levels of soil organic matter and microbially-mediated biogeochemical functions. Another important biogeochemical parameter for soil bacterial communities is pH, which influenced the bacterial community composition, consistent with studies in non-urban soils. Bacterial community composition in GI features showed signs of anthropogenic disturbance, including exposure to animal feces and chemical contaminants, such as petroleum products. Results suggest the overall design and management of GI features with a channeled connection with street runoff, such as ROWB, have a comprehensive effect on soil parameters (particularly organic matter) and the bacterial community. One key consideration for future assessments of GI microbial community would be to determine the source of organic matter and elucidate the relationship between vegetation, Technosol, and bacteria in the designed GI features.}, }
@article {pmid31154270, year = {2019}, author = {Yue, SJ and Liu, J and Wang, WX and Wang, AT and Yang, XY and Guan, HS and Wang, CY and Yan, D}, title = {Berberine treatment-emergent mild diarrhea associated with gut microbiota dysbiosis.}, journal = {Biomedicine &amp; pharmacotherapy = Biomedecine &amp; pharmacotherapie}, volume = {116}, number = {}, pages = {109002}, doi = {10.1016/j.biopha.2019.109002}, pmid = {31154270}, issn = {1950-6007}, abstract = {Berberine (BBR) is a non-prescription drug to treat various bacteria-associated diarrheas. However, BBR has also been reported to cause diarrhea in clinic, with underlying mechanisms poorly understood. Because altered gut microbial ecology is a potential basis for diarrhea, this study was conducted to investigate the impact of BBR on gut microbiota of treatment-emergent diarrhea. BBR treatment (200 mg/kg, i.g.) in normal rats exhibited no significant changes in serum biochemical parameters but mild diarrhea occurred, accompanied with the decreased gastrointestinal transit time and increased fecal moisture, suggestive of the local effects of BBR in the intestine. Colon histology revealed the decreased abundance of mucus-filled goblet cells in BBR group. Although BBR-treated rats had the enlarged cecum with watery caecal digesta, short-chain fatty acids concentration was significantly lower than control group. Additionally, BBR caused gut microbiota dysbiosis by evaluating the decreased observed species number and Shannon index. BBR increased the relative abundances of families Porphyromonadaceae and Prevotellaceae as well as genera Parabacteroides, Prevotellaceae_UCG-001 and Prevotellaceae_NK3B31_group. Spearman's correlation analysis revealed family Prevotellaceae and genus Prevotellaceae_UCG-001 as the most prominent drivers of the BBR treatment-emergent diarrhea, correlating positively with fecal moisture but negatively with gastrointestinal transit time. This study therefore demonstrated that the treatment-emergent mild diarrhea of BBR was most likely due to the dysbiosis of the gut microbiota.}, }
@article {pmid31152013, year = {2019}, author = {Herlemann, DPR and Markert, S and Meeske, C and Andersson, AF and de Bruijn, I and Hentschker, C and Unfried, F and Becher, D and Jürgens, K and Schweder, T}, title = {Individual physiological adaptations enable selected bacterial taxa to prevail during long-term incubations.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1128/AEM.00825-19}, pmid = {31152013}, issn = {1098-5336}, abstract = {Enclosure experiments are frequently used to investigate the impact of changing environmental conditions on microbial assemblages. Yet, how the incubation itself challenges complex bacterial communities is thus far unknown. In this study, metaproteomic profiling, 16S rRNA gene analyses and cell counts were combined to evaluate bacterial communities derived from marine, mesohaline and oligohaline conditions after long-term batch incubations. Early in the experiment, the three bacterial communities were highly diverse and differed significantly in their composition. Manipulation of the enclosures with terrigenous dissolved organic carbon resulted in notable differences compared to the control enclosures at this early phase of the experiment. However, after 55 days, bacterial communities in the manipulated and the control enclosures at marine and mesohaline conditions were all dominated by gammaproteobacterial Spongiibacter In the oligohaline enclosures, actinobacterial hgc-I remained abundant in the late phase of the incubation. Metaproteome analyses suggested that the ability to use outer membrane-based internal energy stores, in addition to the previously described grazing resistance, may enable the gammaproteobacterial Spongiibacter to prevail in long time incubations. Under oligohaline conditions the utilization of external recalcitrant carbon seem to be more important (hgc-I). Enclosure experiments with complex natural microbial communities are important tools to investigate the effects of manipulations. However, species-specific properties, such as individual carbon storage strategies can cause manipulation-independent effects and need to be considered when interpreting results from enclosures.ImportanceIn microbial ecology, enclosure studies are often used to investigate the effect of single environmental factors on complex bacterial communities. However, in addition to the manipulation, unintended effects (&quot;bottle effect&quot;) may occur due to the enclosure itself. In this study we analyzed the bacterial communities that originated from three different salinities of the Baltic Sea, comparing their composition and physiological activity both at the early stage and after 55 days of incubation. Our results suggested that internal carbon storage strategies impact the success of certain bacterial species, independent of the experimental manipulation. Thus, while enclosure experiments remain valid tools in environmental research, microbial community composition shifts must be critically followed. This investigation of the metaproteome during long-term batch enclosures expanded our current understanding of the so-called &quot;bottle effect&quot;, which is well-known to occur during enclosure experiments.}, }
@article {pmid31147731, year = {2019}, author = {Arias, A and Saiz, E and Calbet, A}, title = {Towards an Understanding of Diel Feeding Rhythms in Marine Protists: Consequences of Light Manipulation.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01390-y}, pmid = {31147731}, issn = {1432-184X}, support = {FERMI (CGL2014-59227-R)//MINECO/FEDER, UE/ ; FPI (BES-2015-074092)//MINECO/ ; }, abstract = {Temporal programs synchronised with the daily cycle are of adaptive importance for organisms exposed to periodic fluctuations. This study deepens into several aspects of the exogenous and endogenous nature of microbial grazers. We investigated the diel rhythms of cell division and feeding activity of four marine protists under different light regimes. In particular, we tested if the feeding cycle of protistan grazers could be mediated by a light-aided enhancement of prey digestion, and also explored the consequences of cell division on diel feeding rhythms. Cell division occurred at night for the heterotrophic dinoflagellates Gyrodinium dominans and Oxyrrhis marina. In contrast, the mixotrophic dinoflagellate Karlodinium armiger and the ciliate Strombidium sp. mostly divided during the day. Additionally, a significant diurnal feeding rhythm was observed in all species. When exposed to continuous darkness, nearly all species maintained the cell division rhythm, but lost the feeding cycle within several hours/days (with the exception of O. marina that kept the rhythm for 9.5 days). Additional feeding experiments under continuous light also showed the same pattern. We conclude that the feeding rhythms of protistan grazers are generally regulated not by cell division nor by the enhancement of digestion by light. Our study, moreover, indicates that the cell division cycle is under endogenous control, whereas an external trigger is required to maintain the feeding rhythm, at least for most of the species studied here.}, }
@article {pmid31145076, year = {2019}, author = {Farfour, E and Henry, A and Razillard, A and Cardot, E and Limousin, L and Cahen, P and Jolly, E and Vasse, M and Mathonnet, D}, title = {Rapid identification of Escherichia coli colonies from clinical sample inoculated on CHROMagar Orientation media (Becton Dickinson).}, journal = {Annales de biologie clinique}, volume = {}, number = {}, pages = {}, doi = {10.1684/abc.2019.1446}, pmid = {31145076}, issn = {1950-6112}, abstract = {CHROMmagar Orientation media (Becton Dickinson) was developed and validated for the culture of urinary samples. It allows a direct identification of E. coli colonies without additional tests. As CHROMmagar Orientation media is superior to non-chromogenic media for the distinction of enterobacterial colonies, it is used for the inoculation of a large variety of samples in clinical laboratories. Direct identification of E. coli colonies cultured from these samples is not validated by the manufacturer. The difference in microbial ecology and the nature of the sample may impact CHROMagar Orientation performances for this use. We evaluated these media for the direct identification of E. coli colonies from 410 samples (excluding urine). Its sensitivity of 99% allows a direct identification of E. coli colonies cultured from a wide variety of samples. On-site testing using a large number of representative samples, allows laboratories to assess agar media performance and adapt their uses. Suppliers who are aware of frequent and non-recommended use of their culture media should perform tests and if conclusive, adapt their technical instructions.}, }
@article {pmid31144710, year = {2019}, author = {Villa-Rodriguez, JA and Ifie, I and Gonzalez-Aguilar, GA and Roopchand, DE}, title = {The Gastrointestinal Tract as Prime Site for Cardiometabolic Protection by Dietary Polyphenols.}, journal = {Advances in nutrition (Bethesda, Md.)}, volume = {}, number = {}, pages = {}, doi = {10.1093/advances/nmz038}, pmid = {31144710}, issn = {2156-5376}, abstract = {Substantial evidence from nutritional epidemiology links polyphenol-rich diets with reduced incidence of chronic disorders; however, biological mechanisms underlying polyphenol-disease relations remain enigmatic. Emerging evidence is beginning to unmask the contribution of the gastrointestinal tract on whole-body energy homeostasis, suggesting that the intestine may be a prime target for intervention and a fundamental site for the metabolic actions of polyphenols. During their transit through the gastrointestinal tract, polyphenols may activate enteric nutrient sensors ensuing appropriate responses from other peripheral organs to regulate metabolic homeostasis. Furthermore, polyphenols can modulate the absorption of glucose, attenuating exaggerated hormonal responses and metabolic imbalances. Polyphenols that escape absorption are metabolized by the gut microbiota and the resulting catabolites may act locally, activating nuclear receptors that control enteric functions such as intestinal permeability. Finally, polyphenols modulate gut microbial ecology, which can have profound effects on cardiometabolic health.}, }
@article {pmid31144004, year = {2019}, author = {Clairmont, LK and Slawson, RM}, title = {Contrasting Water Quality Treatments Result in Structural and Functional Changes to Wetland Plant-Associated Microbial Communities in Lab-Scale Mesocosms.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01389-5}, pmid = {31144004}, issn = {1432-184X}, support = {GR-RGPGP 2014-00060-R//Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada/ ; 471103-2015, PGSD//Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada/ ; }, abstract = {The impact of contrasting water quality treatments on wetland plant-associated microbial communities was investigated in this study using 12 lab-scale wetland mesocosms (subsurface flow design) planted with reed canary grass (Phalaris arundinacea) or water speedwell (Veronica anagallis-aquatica) over a 13-week period. Mesocosms received water collected from two sites along the Grand River (Ontario, Canada) designated as having either high or poor water quality according to Grand River Conservation Authority classifications. All mesocosms were established using sediment collected from the high water quality site and received water from this source pre-treatment. Resulting changes to microbial community structure were assessed using PCR-denaturing gel gradient electrophoresis (DGGE) on microbial 16S rDNA sequences extracted from rhizoplane, rhizosphere, and water samples before and after exposure to water quality treatments. Functional community changes were determined using Biolog™ EcoPlates which assess community-level carbon source utilization profiles. Wetland mesocosm removal of inorganic nutrients (N, P) and fecal coliforms was also determined, and compared among treatments. Treatment-specific effects were assessed using a repeated measures restricted maximum likelihood (REML) analysis. Structural and functional characteristics of rhizoplane microbial communities were significantly influenced by the interaction between plant species and water treatment (P = 0.04, P = 0.01). Plant species-specific effects were observed for rhizosphere structural diversity (P = 0.01) and wetland water community metabolic diversity (P = 0.03). The effect of water treatment alone was significant for structural diversity measurements in wetland water communities (P = 0.03). The effect of plant species, water quality treatment, and the interaction between the two is dependent on the microhabitat type (rhizoplane, rhizosphere, or water). Rhizoplane communities appear to be more sensitive to water quality-specific environmental changes and may be a good candidate for microbial community-based monitoring of wetland ecosystems.}, }
@article {pmid31144003, year = {2019}, author = {Han, D and Kang, HY and Kang, CK and Unno, T and Hur, HG}, title = {Seasonal Mixing-Driven System in Estuarine-Coastal Zone Triggers an Ecological Shift in Bacterial Assemblages Involved in Phytoplankton-Derived DMSP Degradation.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01392-w}, pmid = {31144003}, issn = {1432-184X}, support = {Long-term Marine Ecosystem Research//Ministry of Oceans and Fisheries/ ; NRF-2016R1A6A3A11931896//National Research Foundation of Korea/ ; }, abstract = {The coastal zone has distinguishable but tightly connected ecosystems from rivers to the ocean and globally contributes to nutrient cycling including phytoplankton-derived organic matter. Particularly, bacterial contributions to phytoplankton-derived dimethylsulfoniopropionate (DMSP) degradation have been recently evaluated by using advanced sequencing technologies to understand their role in the marine microbial food web. Here, we surveyed the bacterial diversity and community composition under seasonal water mixing in the bay of Gwangyang (GW), a semi-enclosed estuary at the southern tip of the Korea Peninsula. We detected phylogenetic dissimilarities among season-specific habitats in GW and their specific bacterial taxa. Additionally, bacterial contribution to degradation of phytoplankton-derived DMSP from estuarine to coastal waters at euphotic depths in GW was investigated as the presence or absence of DMSP demethylation gene, encoded by dmdA. Among the operational taxonomic units (OTUs) in GW bacterial communities, the most dominant and ubiquitous OTU1 was affiliated with the SAR11 clade (SAR11-OTU). The population dynamics of SAR11-OTU in dmdA-detected GW waters suggest that water mass mixing plays a major role in shaping bacterial communities involved in phytoplankton-derived DMSP demethylation.}, }
@article {pmid31144002, year = {2019}, author = {Bittar, C and Machado, RRG and Comelis, MT and Bueno, LM and Beguelini, MR and Morielle-Versute, E and Nogueira, ML and Rahal, P}, title = {Alphacoronavirus Detection in Lungs, Liver, and Intestines of Bats from Brazil.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01391-x}, pmid = {31144002}, issn = {1432-184X}, support = {2015/09704-6//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 165802/2015-4//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {Bats are flying mammals distributed worldwide known to host several types of Coronavirus (CoV). Since they were reported as the probable source of spillover of highly pathogenic CoV into the human population, investigating the circulation of this virus in bats around the world became of great importance. We analyzed samples from 103 bats from two distinct regions in Brazil. Coronavirus from the Alphacoronavirus genus was detected in 12 animals, 11 from São José do Rio Preto-SP region and 1 from Barreiras-BA region, resulting in a prevalence of 17.18% and 2.56% respectively. The virus was detected not only in intestines but also in lungs and liver. Phylogenetic analysis based on nsP12 genomic region suggests that the sequences group according to host family and sampling location. Studies on the circulation of these viruses in bats remain important to understand the ecology and evolutionary relationship of these pathogens.}, }
@article {pmid31143408, year = {2019}, author = {Conrads, G and Wendt, LK and Hetrodt, F and Deng, ZL and Pieper, D and Abdelbary, MMH and Barg, A and Wagner-Döbler, I and Apel, C}, title = {Deep sequencing of biofilm microbiomes on dental composite materials.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1617013}, doi = {10.1080/20002297.2019.1617013}, pmid = {31143408}, issn = {2000-2297}, abstract = {Background: The microbiome on dental composites has not been studied in detail before. It has not been conclusively clarified whether restorative materials influence the oral microbiome. Methods: We used Illumina Miseq next-generation sequencing of the 16S V1-V2 region to compare the colonisation patterns of bovine enamel (BE) and the composite materials Grandio Flow (GF) and Grandio Blocs (GB) after 48 h in vivo in 14 volunteers. Applying a new method to maintain the oral microbiome ex vivo for 48 h also, we compared the microbiome on GF alone and with the new antimicrobial substance carolacton (GF+C). Results: All in vitro biofilm communities showed a higher diversity and richness than those grown in vivo but the very different atmospheric conditions must be considered. Contrary to expectations, there were only a few significant differences between BE and the composite materials GB and GF either in vivo or in vitro: Oribacterium, Peptostreptococcaceae [XI][G-1] and Streptococcus mutans were more prevalent and Megasphaera, Prevotella oulorum, Veillonella atypica, V. parvula, Gemella morbillorum, and Fusobacterium periodonticum were less prevalent on BE than on composites. In vivo, such preferences were only significant for Granulicatella adiacens (more prevalent on BE) and Fusobacterium nucleatum subsp. animalis (more prevalent on composites). On DNA sequence level, there were no significant differences between the biofilm communities on GF and GF+C. Conclusion: We found that the oral microbiome showed an increased richness when grown on various composites compared to BE in vitro, but otherwise changed only slightly independent of the in vivo or in vitro condition. Our new ex vivo biofilm model might be useful for pre-clinical testing of preventive strategies.}, }
@article {pmid31143165, year = {2019}, author = {Miller, JI and Techtmann, S and Fortney, J and Mahmoudi, N and Joyner, D and Liu, J and Olesen, S and Alm, E and Fernandez, A and Gardinali, P and GaraJayeva, N and Askerov, FS and Hazen, TC}, title = {Oil Hydrocarbon Degradation by Caspian Sea Microbial Communities.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {995}, doi = {10.3389/fmicb.2019.00995}, pmid = {31143165}, issn = {1664-302X}, abstract = {The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural and municipal sources, containing nutrients that have caused eutrophication and subsequent hypoxia in the deep, cold waters. The effect of decreasing oxygen saturation and cold temperatures on oil hydrocarbon biodegradation by a microbial community is not well characterized. The purpose of this study was to investigate the effect of oxic and anoxic conditions on oil hydrocarbon biodegradation at cold temperatures by microbial communities derived from the Caspian Sea. Water samples were collected from the Caspian Sea for study in experimental microcosms. Major taxonomic orders observed in the ambient water samples included Flavobacteriales, Actinomycetales, and Oceanospirillales. Microcosms were inoculated with microbial communities from the deepest waters and amended with oil hydrocarbons for 17 days. Hydrocarbon degradation and shifts in microbial community structure were measured. Surprisingly, oil hydrocarbon biodegradation under anoxic conditions exceeded that under oxic conditions; this was particularly evident in the degradation of aromatic hydrocarbons. Important microbial taxa associated with the anoxic microcosms included known oil degraders such as Oceanospirillaceae. This study provides knowledge about the ambient community structure of the Caspian Sea, which serves as an important reference point for future studies. Furthermore, this may be the first report in which anaerobic biodegradation of oil hydrocarbons exceeds aerobic biodegradation.}, }
@article {pmid31143163, year = {2019}, author = {Kuramae, EE and Leite, MFA and Suleiman, AKA and Gough, CM and Castillo, BT and Faller, L and Franklin, RB and Syring, J}, title = {Wood Decay Characteristics and Interspecific Interactions Control Bacterial Community Succession in Populus grandidentata (Bigtooth Aspen).}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {979}, doi = {10.3389/fmicb.2019.00979}, pmid = {31143163}, issn = {1664-302X}, abstract = {Few studies have investigated bacterial community succession and the role of bacterial decomposition over a continuum of wood decay. Here, we identified how (i) the diversity and abundance of bacteria changed along a chronosequence of decay in Populus grandidentata (bigtooth aspen); (ii) bacterial community succession was dependent on the physical and chemical characteristics of the wood; (iii) interspecific bacterial interactions may mediate community structure. Four hundred and fifty-nine taxa were identified through Illumina sequencing of 16S rRNA amplicons from samples taken along a continuum of decay, representing standing dead trees, downed wood, and soil. Community diversity increased as decomposition progressed, peaking in the most decomposed trees. While a small proportion of taxa displayed a significant pattern in regards to decay status of the host log, many bacterial taxa followed a stochastic distribution. Changes in the water availability and chemical composition of standing dead and downed trees and soil were strongly coupled with shifts in bacterial communities. Nitrogen was a major driver of succession and nitrogen-fixing taxa of the order Rhizobiales were abundant early in decomposition. Recently downed logs shared 65% of their bacterial abundance with the microbiomes of standing dead trees while only sharing 16% with soil. As decay proceeds, bacterial communities appear to respond less to shifting resource availability and more to interspecific bacterial interactions - we report an increase in both the proportion (+9.3%) and the intensity (+62.3%) of interspecific interactions in later stages of decomposition, suggesting the emergence of a more complex community structure as wood decay progresses.}, }
@article {pmid31139578, year = {2019}, author = {Castillo, DJ and Rifkin, RF and Cowan, DA and Potgieter, M}, title = {The Healthy Human Blood Microbiome: Fact or Fiction?.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {148}, doi = {10.3389/fcimb.2019.00148}, pmid = {31139578}, issn = {2235-2988}, abstract = {The blood that flows perpetually through our veins and arteries performs numerous functions essential to our survival. Besides distributing oxygen, this vast circulatory system facilitates nutrient transport, deters infection and dispenses heat throughout our bodies. Since human blood has traditionally been considered to be an entirely sterile environment, comprising only blood-cells, platelets and plasma, the detection of microbes in blood was consistently interpreted as an indication of infection. However, although a contentious concept, evidence for the existence of a healthy human blood-microbiome is steadily accumulating. While the origins, identities and functions of these unanticipated micro-organisms remain to be elucidated, information on blood-borne microbial phylogeny is gradually increasing. Given recent advances in microbial-hematology, we review current literature concerning the composition and origin of the human blood-microbiome, focusing on bacteria and their role in the configuration of both the diseased and healthy human blood-microbiomes. Specifically, we explore the ways in which dysbiosis in the supposedly innocuous blood-borne bacterial microbiome may stimulate pathogenesis. In addition to exploring the relationship between blood-borne bacteria and the development of complex disorders, we also address the matter of contamination, citing the influence of contaminants on the interpretation of blood-derived microbial datasets and urging the routine analysis of laboratory controls to ascertain the taxonomic and metabolic characteristics of environmentally-derived contaminant-taxa.}, }
@article {pmid31139170, year = {2019}, author = {León-Sobrino, C and Ramond, JB and Maggs-Kölling, G and Cowan, DA}, title = {Nutrient Acquisition, Rather Than Stress Response Over Diel Cycles, Drives Microbial Transcription in a Hyper-Arid Namib Desert Soil.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1054}, doi = {10.3389/fmicb.2019.01054}, pmid = {31139170}, issn = {1664-302X}, abstract = {Hot desert surface soils are characterized by extremely low water activities for large parts of any annual cycle. It is widely assumed that microbial processes in such soils are very limited. Here we present the first metatranscriptomic survey of microbial community function in a low water activity hyperarid desert soil. Sequencing of total mRNA revealed a diverse and active community, dominated by Actinobacteria. Metatranscriptomic analysis of samples taken at different times over 3 days indicated that functional diel variations were limited at the whole community level, and mostly affected the eukaryotic subpopulation which was induced during the cooler night hours. High levels of transcription of chemoautotrophic carbon fixation genes contrasted with limited expression of photosynthetic genes, indicating that chemoautotrophy is an important alternative to photosynthesis for carbon cycling in desiccated desert soils. Analysis of the transcriptional levels of key N-cycling genes provided strong evidence that soil nitrate was the dominant nitrogen input source. Transcriptional network analyses and taxon-resolved functional profiling suggested that nutrient acquisition processes, and not diurnal environmental variation, were the main drivers of community activity in hyperarid Namib Desert soil. While we also observed significant levels of expression of common stress response genes, these genes were not dominant hubs in the co-occurrence network.}, }
@article {pmid31138723, year = {2019}, author = {Emerson, JB}, title = {Soil Viruses: A New Hope.}, journal = {mSystems}, volume = {4}, number = {3}, pages = {}, doi = {10.1128/mSystems.00120-19}, pmid = {31138723}, issn = {2379-5077}, abstract = {As abundant members of microbial communities, viruses impact microbial mortality, carbon and nutrient cycling, and food web dynamics. Although most of our information about viral communities comes from marine systems, evidence is mounting to suggest that viruses are similarly important in soil. Here I outline soil viral metagenomic approaches and the current state of soil viral ecology as a field, and then I highlight existing knowledge gaps that we can begin to fill. We are poised to elucidate soil viral contributions to terrestrial ecosystem processes, considering: the full suite of potential hosts across trophic scales, the ecological impacts of different viral replication strategies, links to economically relevant outcomes like crop productivity, and measurable in situ virus-host population dynamics across spatiotemporal scales and environmental conditions. Soon, we will learn how soil viruses contribute to food webs linked to organic matter decomposition, carbon and nutrient cycling, greenhouse gas emissions, and agricultural productivity.}, }
@article {pmid31138673, year = {2019}, author = {Benítez-Páez, A and Kjølbæk, L and Gómez Del Pulgar, EM and Brahe, LK and Astrup, A and Matysik, S and Schött, HF and Krautbauer, S and Liebisch, G and Boberska, J and Claus, S and Rampelli, S and Brigidi, P and Larsen, LH and Sanz, Y}, title = {A Multi-omics Approach to Unraveling the Microbiome-Mediated Effects of Arabinoxylan Oligosaccharides in Overweight Humans.}, journal = {mSystems}, volume = {4}, number = {4}, pages = {}, doi = {10.1128/mSystems.00209-19}, pmid = {31138673}, issn = {2379-5077}, abstract = {Long-term consumption of dietary fiber is generally considered beneficial for weight management and metabolic health, but the results of interventions vary greatly depending on the type of dietary fibers involved. This study provides a comprehensive evaluation of the effects of a specific dietary fiber consisting of a wheat-bran extract enriched in arabinoxylan-oligosaccharides (AXOS) in a human intervention trial. An integrated multi-omics analysis has been carried out to evaluate the effects of an intervention trial with an AXOS-enriched diet in overweight individuals with indices of metabolic syndrome. Microbiome analyses were performed by shotgun DNA sequencing in feces; in-depth metabolomics using nuclear magnetic resonance in fecal, urine, and plasma samples; and massive lipid profiling using mass spectrometry in fecal and serum/plasma samples. In addition to their bifidogenic effect, we observed that AXOS boost the proportion of Prevotella species. Metagenome analysis showed increases in the presence of bacterial genes involved in vitamin/cofactor production, glycan metabolism, and neurotransmitter biosynthesis as a result of AXOS intake. Furthermore, lipidomics analysis revealed reductions in plasma ceramide levels. Finally, we observed associations between Prevotella abundance and short-chain fatty acids (SCFAs) and succinate concentration in feces and identified a potential protective role of Eubacterium rectale against metabolic disease given that its abundance was positively associated with plasma phosphatidylcholine levels, thus hypothetically reducing bioavailability of choline for methylamine biosynthesis. The metagenomics, lipidomics, and metabolomics data integration indicates that sustained consumption of AXOS orchestrates a wide variety of changes in the gut microbiome and the host metabolism that collectively would impact on glucose homeostasis. (This study has been registered at ClinicalTrials.gov under identifier NCT02215343)IMPORTANCE The use of dietary fiber food supplementation as a strategy to reduce the burden of diet-related diseases is a matter of study given its cost-effectiveness and the positive results demonstrated in clinical trials. This multi-omics assessment, on different biological samples of overweight subjects with signs of metabolic syndrome, sheds light on the early and less evident effects of short-term AXOS intake on intestinal microbiota and host metabolism. We observed a deep influence of AXOS on gut microbiota beyond their recognized bifidogenic effect by boosting concomitantly a wide diversity of butyrate producers and Prevotella copri, a microbial species abundant in non-Westernized populations with traditional lifestyle and diets enriched in fresh unprocessed foods. A comprehensive evaluation of hundreds of metabolites unveiled new benefits of the AXOS intake, such as reducing the plasma ceramide levels. Globally, we observed that multiple effects of AXOS consumption seem to converge in reversing the glucose homeostasis impairment.}, }
@article {pmid31132623, year = {2019}, author = {Liu, L and Wu, L and Knauth, S and Eickhorst, T}, title = {Degradation of transgenic Bt-rice straw incorporated with two different paddy soils.}, journal = {Journal of environmental management}, volume = {244}, number = {}, pages = {415-421}, doi = {10.1016/j.jenvman.2019.05.075}, pmid = {31132623}, issn = {1095-8630}, abstract = {Transgenic Bt-rice is rice that has been genetically modified to produce insecticidal proteins (Cry1Ab/Ac) within the plant. Rice straw is incorporated into paddy soils after harvest for fertilization or to improve the soil structure. The incorporation of straw from transgenic Bt-rice may pose risks to the paddy soil system. The decomposition of Bt-rice straw and degradation of Cry1Ab/Ac proteins from the straw were investigated under laboratory conditions. In addition, effects of the incorporation with chopped rice straw on microbial communities in differently textured paddy soils were studied. The results indicated that the incorporation of straw from transgenic Bt-rice might have a slight influence on soil respiration and CH4 emissions in two paddy soils, i.e. the Silt Loam soil and the Silty Clay soil. Differences were also observed in the cumulative emissions of CO2 between the two amended paddy soils in addition to the well-known increase in emissions of both CO2 and CH4 due to straw incorporation. The Cry1Ab/Ac proteins from straw of transgenic Bt-rice were degraded in paddy soils. The rate of decline in the concentration of Cry1Ab/Ac proteins was different in the two soils. After 29 d of incubation, 61% and 42% of initial Cry1Ab/Ac proteins were detected in the silt loam and silty clay, respectively. As a result of the presence of the rice straw, the abundance of bacteria, archaea, and total cells were increased in two soils. The numbers of bacteria and total cells were 6.4% and 11.5% higher in the silt loam amended with straw of Bt-rice than non-Bt-rice, respectively. The silty clay displayed a similar trend as the silt loam.}, }
@article {pmid31130935, year = {2019}, author = {Cramm, MA and Chakraborty, A and Li, C and Ruff, SE and Jørgensen, BB and Hubert, CRJ}, title = {Freezing Tolerance of Thermophilic Bacterial Endospores in Marine Sediments.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {945}, doi = {10.3389/fmicb.2019.00945}, pmid = {31130935}, issn = {1664-302X}, abstract = {Dormant endospores of anaerobic, thermophilic bacteria found in cold marine sediments offer a useful model for studying microbial biogeography, dispersal, and survival. The dormant endospore phenotype confers resistance to unfavorable environmental conditions, allowing dispersal to be isolated and studied independently of other factors such as environmental selection. To study the resilience of thermospores to conditions relevant for survival in extreme cold conditions, their viability following different freezing treatments was tested. Marine sediment was frozen at either -80°C or -20°C for 10 days prior to pasteurization and incubation at +50°C for 21 days to assess thermospore viability. Sulfate reduction commenced at +50°C following both freezing pretreatments indicating persistence of thermophilic endospores of sulfate-reducing bacteria. The onset of sulfate reduction at +50°C was delayed in -80°C pretreated microcosms, which exhibited more variability between triplicates, compared to -20°C pretreated microcosms and parallel controls that were not frozen in advance. Microbial communities were evaluated by 16S rRNA gene amplicon sequencing, revealing an increase in the relative sequence abundance of thermophilic endospore-forming Firmicutes in all microcosms. Different freezing pretreatments (-80°C and -20°C) did not appreciably influence the shift in overall bacterial community composition that occurred during the +50°C incubations. Communities that had been frozen prior to +50°C incubation showed an increase in the relative sequence abundance of operational taxonomic units (OTUs) affiliated with the class Bacilli, relative to unfrozen controls. These results show that freezing impacts but does not obliterate thermospore populations and their ability to germinate and grow under appropriate conditions. Indeed the majority of the thermospore OTUs detected in this study (21 of 22) could be observed following one or both freezing treatments. These results are important for assessing thermospore viability in frozen samples and following cold exposure such as the very low temperatures that would be encountered during panspermia.}, }
@article {pmid31129882, year = {2019}, author = {Huh, YJ and Seo, JY and Nam, J and Yang, J and McDowell, A and Kim, YK and Lee, JH}, title = {Bariatric/Metabolic Surgery Induces Noticeable Changes of Microbiota and Their Secreting Extracellular Vesicle Composition in the Gut.}, journal = {Obesity surgery}, volume = {}, number = {}, pages = {}, doi = {10.1007/s11695-019-03852-1}, pmid = {31129882}, issn = {1708-0428}, support = {NRF-2016R1D1A1B03932360//National Research Foundation of Korea/ ; }, abstract = {INTRODUCTION: Microbial ecology is reported to be an important regulator of energy homeostasis and glucose metabolism. Microbes secrete extracellular vesicles (EVs) during their proliferation and death to communicate with other cells. To investigate the roles of gut microbiota in glucose metabolism, we analyzed serial changes of gut microbe and microbial EV composition before and after bariatric/metabolic surgery (BMS).<br><br>METHODS: Twenty-eight Wistar rats were fed on high-fat diet (HFD) to induce obesity and diabetes. Five of them compared with 5 rats fed on regular chow diet (RCD). Among the remaining 23 rats, Roux-en-Y gastric bypass (RYGB) (n = 10), sleeve gastrectomy (SG) (n = 10), or sham operation (n = 3) was randomly performed. Gut microbiota and EVs from fecal samples were analyzed by 16S rDNA amplicon sequencing.<br><br>RESULTS: The present study showed that microbial diversity was decreased in HFD-fed rats versus RCD-fed rats. In addition, BMS reversed glucose intolerance and microbial richness which were induced by HFD. In terms of microbiota and microbial EV composition, both RYGB and SG enhance the composition of phyla Proteobacteria, Verrucomicrobia, and their secreting EVs, but decrease phylum Firmicutes and its EVs. We tried to demonstrate specific genera showed a significant compositional difference in obesity/diabetes-induced rats compared with normal rats and then restored similarly toward normal rats' level after BMS. At the genus level, Lactococcus, Ruminococcus, Dorea in Firmicutes(p), Psychrobacter in Proteobacteria(p), and Akkermansia in Verrucomicrobia(p) fit these conditions after BMS.<br><br>CONCLUSION: We suggest that these genera are the candidates contributing to obesity and diabetes improvement mechanism after BMS.}, }
@article {pmid31129376, year = {2019}, author = {Meng, Y and Zhou, Z and Meng, F}, title = {Impacts of diel temperature variations on nitrogen removal and metacommunity of anammox biofilm reactors.}, journal = {Water research}, volume = {160}, number = {}, pages = {1-9}, doi = {10.1016/j.watres.2019.05.021}, pmid = {31129376}, issn = {1879-2448}, abstract = {The influence of diel temperature variations (DTVs) on nitrogen removal and bacterial communities was investigated in two parallel anammox reactors (i.e., control and DTV reactors). The control reactor was operated at a constant temperature of 30 °C, whereas the DTV reactor was operated in a temperature fluctuation mode with a cycle of 12/12 h of high/low temperatures. Nine water temperature variations for the day/night periods were set from 30/30 °C (i.e., Δ0 °C) to 38/22 °C (i.e., Δ16 °C). An increase in DTVs from Δ8 °C (34/26 °C) to Δ16 °C (38/22 °C) caused a significant decline in reactor performance and a shift in bacterial diversity. Compared to the control reactor, for instance, nitrogen removal efficiency decreased (P < 0.05) when temperature fluctuations exceeded Δ8 °C in the DTV reactor with a decreasing ΔNO3-/ΔNH4+ ratio (from 0.21 ± 0.15 to 0.16 ± 0.04). The results of 16S rRNA gene sequencing showed that the initial disturbance of temperature variations led to increased levels of bacterial diversity (i.e., alpha diversity) and decreased community levels of anammox consortia whereas they slightly recovered at the end of each DTV phase. Notably, Candidatus Jettenia was more sensitive to strong water temperature fluctuations, with the lower relative abundance at Δ14 °C (17.11 ± 5.01%) and Δ16 °C (17.83 ± 7.22%) than at Δ4 °C (39.82 ± 0.01%). In contrast, Ca. Brocadia and Ca. Kuenenia had higher relative abundance at Δ14 °C (i.e., 0.24 ± 0.07% and 0.09 ± 0.02%, respectively) and Δ16 °C (i.e., 0.28 ± 0.05% and 0.12 ± 0.03%, respectively) compared to that at Δ4 °C (i.e., 0.15 ± 0.04% and 0.04 ± 0.01%, respectively). Nitrifiers (i.e., unidentified_Nitrospiraceae and Nitrosomonas) and denitrifiers (i.e., Denitratisoma) were also capable of tolerating high temperature perturbations. Overall this study furthers our knowledge of responses of the microbial ecology of anammox bacteria to DTVs in anammox processes, which could aid us in optimizing anammox-related wastewater treatment systems and in understanding the nitrogen cycles of natural ecosystems.}, }
@article {pmid31128471, year = {2019}, author = {Tsao, HF and Scheikl, U and Herbold, C and Indra, A and Walochnik, J and Horn, M}, title = {The cooling tower water microbiota: Seasonal dynamics and co-occurrence of bacterial and protist phylotypes.}, journal = {Water research}, volume = {159}, number = {}, pages = {464-479}, doi = {10.1016/j.watres.2019.04.028}, pmid = {31128471}, issn = {1879-2448}, abstract = {Cooling towers for heating, ventilation and air conditioning are ubiquitous in the built environment. Often located on rooftops, their semi-open water basins provide a suitable environment for microbial growth. They are recognized as a potential source of bacterial pathogens and have been associated with disease outbreaks such as Legionnaires' disease. While measures to minimize public health risks are in place, the general microbial and protist community structure and dynamics in these systems remain largely elusive. In this study, we analysed the microbiome of the bulk water from the basins of three cooling towers by 16S and 18S rRNA gene amplicon sequencing over the course of one year. Bacterial diversity in all three towers was broadly comparable to other freshwater systems, yet less diverse than natural environments; the most abundant taxa are also frequently found in freshwater or drinking water. While each cooling tower had a pronounced site-specific microbial community, taxa shared among all locations mainly included groups generally associated with biofilm formation. We also detected several groups related to known opportunistic pathogens, such as Legionella, Mycobacterium, and Pseudomonas species, albeit at generally low abundance. Although cooling towers represent a rather stable environment, microbial community composition was highly dynamic and subject to seasonal change. Protists are important members of the cooling tower water microbiome and known reservoirs for bacterial pathogens. Co-occurrence analysis of bacteria and protist taxa successfully captured known interactions between amoeba-associated bacteria and their hosts, and predicted a large number of additional relationships involving ciliates and other protists. Together, this study provides an unbiased and comprehensive overview of microbial diversity of cooling tower water basins, establishing a framework for investigating and assessing public health risks associated with these man-made freshwater environments.}, }
@article {pmid31125804, year = {2019}, author = {Zhou, LJ and Han, P and Yu, Y and Wang, B and Men, Y and Wagner, M and Wu, QL}, title = {Cometabolic biotransformation and microbial-mediated abiotic transformation of sulfonamides by three ammonia oxidizers.}, journal = {Water research}, volume = {159}, number = {}, pages = {444-453}, doi = {10.1016/j.watres.2019.05.031}, pmid = {31125804}, issn = {1879-2448}, abstract = {The abilities of three phylogenetically distant ammonia oxidizers, Nitrososphaera gargensis, an ammonia-oxidizing archaeon (AOA); Nitrosomomas nitrosa Nm90, an ammonia-oxidizing bacterium (AOB); and Nitrospira inopinata, the only complete ammonia oxidizer (comammox) available as a pure culture, to biotransform seven sulfonamides (SAs) were investigated. The removals and protein-normalized biotransformation rate constants indicated that the AOA strain N. gargensis exhibited the highest SA biotransformation rates, followed by N. inopinata and N. nitrosa Nm90. The transformation products (TPs) of sulfadiazine (SDZ), sulfamethazine (SMZ) and sulfamethoxazole (SMX) and the biotransformation mechanisms were evaluated. Based on the analysis of the TP formulas and approximate structures, it was found that during biotransformation, i) the AOA strain carried out SA deamination, hydroxylation, and nitration; ii) the AOB strain mainly performed SA deamination; and iii) the comammox isolate participated only in deamination reactions. It is proposed that deamination was catalyzed by deaminases while hydroxylation and nitration were mediated by nonspecific activities of the ammonia monooxygenase (AMO). Additionally, it was demonstrated that among the three ammonia oxidizers, only AOB contributed to the formation of pterin-SA conjugates. The biotransformation of SDZ, SMZ and SMX occurred only when ammonia oxidation was active, suggesting a cometabolic transformation mechanism. Interestingly, SAs could also be transformed by hydroxylamine, an intermediate of ammonia oxidation, suggesting that in addition to enzymatic conversions, a microbially induced abiotic mechanism contributes to SA transformation during ammonia oxidation. Overall, using experiments with pure cultures, this study provides important insights into the roles played by ammonia oxidizers in SA biotransformation.}, }
@article {pmid31120557, year = {2019}, author = {Dove, NC and Stark, JM and Newman, GS and Hart, SC}, title = {Carbon control on terrestrial ecosystem function across contrasting site productivities: the carbon connection revisited.}, journal = {Ecology}, volume = {}, number = {}, pages = {e02695}, doi = {10.1002/ecy.2695}, pmid = {31120557}, issn = {1939-9170}, support = {92-37101-7976//U.S. Department of Agriculture Co-operative State Research Service/ ; }, abstract = {Understanding how altered soil organic carbon (SOC) availability affects microbial communities and their function is imperative in predicting impacts of global change on soil carbon (C) storage and ecosystem function. However, the response of soil microbial communities and their function to depleted C availability in situ is unclear. We evaluated the role of soil C inputs in controlling microbial biomass, community composition, physiology, and function by (1) experimentally excluding plant C inputs in situ for 9 yr in four temperate forest ecosystems along a productivity gradient in Oregon, USA; and (2) integrating these findings with published data from similar C-exclusion studies into a global meta-analysis. Excluding plant C inputs for 9 yr resulted in a 13% decrease in SOC across the four Oregon sites and an overall shift in the microbial community composition, with a 45% decrease in the fungal : bacterial ratio and a 13% increase in Gram-positive : Gram-negative bacterial ratio. Although gross N mineralization decreased under C exclusion, decreases in gross N immobilization were greater, resulting in increased net N mineralization rates in all but the lowest-productivity site. Microbial biomass showed a variable response to C exclusion that was method dependent; however, we detected a 29% decrease in C-use efficiency across the sites, with greater declines occurring in less-productive sites. Although extracellular enzyme activity increased with C exclusion, C exclusion resulted in a 31% decrease in microbial respiration across all sites. Our meta-analyses of published data with similar C-exclusion treatments were largely consistent with our experimental results, showing decreased SOC, fungal : bacterial ratios, and microbial respiration, and increased Gram-positive : Gram-negative bacterial ratio following exclusion of C inputs to soil. Effect sizes of SOC and respiration correlated negatively with the duration of C exclusion; however, there were immediate effects of C exclusion on microbial community composition and biomass that were unaltered by duration of treatment. Our field-based experimental results and analyses demonstrate unequivocally the dominant control of C availability on soil microbial biomass, community composition, and function, and provide additional insight into the mechanisms for these effects in forest ecosystems.}, }
@article {pmid31119088, year = {2019}, author = {Roux, S and Trubl, G and Goudeau, D and Nath, N and Couradeau, E and Ahlgren, NA and Zhan, Y and Marsan, D and Chen, F and Fuhrman, JA and Northen, TR and Sullivan, MB and Rich, VI and Malmstrom, RR and Eloe-Fadrosh, EA}, title = {Optimizing de novo genome assembly from PCR-amplified metagenomes.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6902}, doi = {10.7717/peerj.6902}, pmid = {31119088}, issn = {2167-8359}, abstract = {Background: Metagenomics has transformed our understanding of microbial diversity across ecosystems, with recent advances enabling de novo assembly of genomes from metagenomes. These metagenome-assembled genomes are critical to provide ecological, evolutionary, and metabolic context for all the microbes and viruses yet to be cultivated. Metagenomes can now be generated from nanogram to subnanogram amounts of DNA. However, these libraries require several rounds of PCR amplification before sequencing, and recent data suggest these typically yield smaller and more fragmented assemblies than regular metagenomes.<br><br>Methods: Here we evaluate de novo assembly methods of 169 PCR-amplified metagenomes, including 25 for which an unamplified counterpart is available, to optimize specific assembly approaches for PCR-amplified libraries. We first evaluated coverage bias by mapping reads from PCR-amplified metagenomes onto reference contigs obtained from unamplified metagenomes of the same samples. Then, we compared different assembly pipelines in terms of assembly size (number of bp in contigs ≥ 10 kb) and error rates to evaluate which are the best suited for PCR-amplified metagenomes.<br><br>Results: Read mapping analyses revealed that the depth of coverage within individual genomes is significantly more uneven in PCR-amplified datasets versus unamplified metagenomes, with regions of high depth of coverage enriched in short inserts. This enrichment scales with the number of PCR cycles performed, and is presumably due to preferential amplification of short inserts. Standard assembly pipelines are confounded by this type of coverage unevenness, so we evaluated other assembly options to mitigate these issues. We found that a pipeline combining read deduplication and an assembly algorithm originally designed to recover genomes from libraries generated after whole genome amplification (single-cell SPAdes) frequently improved assembly of contigs ≥10 kb by 10 to 100-fold for low input metagenomes.<br><br>Conclusions: PCR-amplified metagenomes have enabled scientists to explore communities traditionally challenging to describe, including some with extremely low biomass or from which DNA is particularly difficult to extract. Here we show that a modified assembly pipeline can lead to an improved de novo genome assembly from PCR-amplified datasets, and enables a better genome recovery from low input metagenomes.}, }
@article {pmid31118299, year = {2019}, author = {Sze, MA and Schloss, PD}, title = {The Impact of DNA Polymerase and Number of Rounds of Amplification in PCR on 16S rRNA Gene Sequence Data.}, journal = {mSphere}, volume = {4}, number = {3}, pages = {}, doi = {10.1128/mSphere.00163-19}, pmid = {31118299}, issn = {2379-5042}, abstract = {PCR amplification of 16S rRNA genes is a critical yet underappreciated step in the generation of sequence data to describe the taxonomic composition of microbial communities. Numerous factors in the design of PCR can impact the sequencing error rate, the abundance of chimeric sequences, and the degree to which the fragments in the product represent their abundance in the original sample (i.e., bias). We compared the performance of high fidelity polymerases and various numbers of rounds of amplification when amplifying a mock community and human stool samples. Although it was impossible to derive specific recommendations, we did observe general trends. Namely, using a polymerase with the highest possible fidelity and minimizing the number of rounds of PCR reduced the sequencing error rate, fraction of chimeric sequences, and bias. Evidence of bias at the sequence level was subtle and could not be ascribed to the fragments' fraction of bases that were guanines or cytosines. When analyzing mock community data, the amount that the community deviated from the expected composition increased with the number of rounds of PCR. This bias was inconsistent for human stool samples. Overall, the results underscore the difficulty of comparing sequence data that are generated by different PCR protocols. However, the results indicate that the variation in human stool samples is generally larger than that introduced by the choice of polymerase or number of rounds of PCR.IMPORTANCE A steep decline in sequencing costs drove an explosion in studies characterizing microbial communities from diverse environments. Although a significant amount of effort has gone into understanding the error profiles of DNA sequencers, little has been done to understand the downstream effects of the PCR amplification protocol. We quantified the effects of the choice of polymerase and number of PCR cycles on the quality of downstream data. We found that these choices can have a profound impact on the way that a microbial community is represented in the sequence data. The effects are relatively small compared to the variation in human stool samples; however, care should be taken to use polymerases with the highest possible fidelity and to minimize the number of rounds of PCR. These results also underscore that it is not possible to directly compare sequence data generated under different PCR conditions.}, }
@article {pmid31117021, year = {2019}, author = {Beinart, RA}, title = {The Significance of Microbial Symbionts in Ecosystem Processes.}, journal = {mSystems}, volume = {4}, number = {3}, pages = {}, doi = {10.1128/mSystems.00127-19}, pmid = {31117021}, issn = {2379-5077}, abstract = {It is increasingly accepted that the microbial symbionts of eukaryotes can have profound effects on host ecology and evolution. However, the relative contribution that they make directly to ecosystem processes, like energy and nutrient flows, is less explicitly acknowledged and, in many cases, only poorly constrained. Here, I explore the idea that, in some habitats, host-associated microbes may have an outsized role in ecosystem processes relative to functionally equivalent free-living microbes due to key aspects of the physiology, ecology, and evolution of symbiotic interactions. My research quantifying symbiont metabolism has shown that microbial symbionts have the potential to make a substantial impact on carbon and sulfur cycling. It is my perspective that direct measurement of symbiont activity and comparison to free-living counterparts will expand our understanding of the significance of microbial symbioses and, more broadly, the role of microbial processes in ecosystems.}, }
@article {pmid31114556, year = {2019}, author = {Hounmanou, YMG and Leekitcharoenphon, P and Hendriksen, RS and Dougnon, TV and Mdegela, RH and Olsen, JE and Dalsgaard, A}, title = {Surveillance and Genomics of Toxigenic Vibrio cholerae O1 From Fish, Phytoplankton and Water in Lake Victoria, Tanzania.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {901}, doi = {10.3389/fmicb.2019.00901}, pmid = {31114556}, issn = {1664-302X}, abstract = {The occurrence of toxigenic Vibrio cholerae O1 during a non- outbreak period in Lake Victoria was studied and genetic characteristics for environmental persistence and relatedness to pandemic strains were assessed. We analyzed 360 samples of carps, phytoplankton and water collected in 2017 during dry and rainy seasons in the Tanzanian basin of Lake Victoria. Samples were tested using PCR (ompW and ctxA) with DNA extracted from bacterial isolates and samples enriched in alkaline peptone water. Isolates were screened with polyvalent antiserum O1 followed by antimicrobial susceptibility testing. Whole genome sequencing and bioinformatics tools were employed to investigate the genomic characteristics of the isolates. More V. cholerae positive samples were recovered by PCR when DNA was obtained from enriched samples than from isolates (69.0% vs. 21.3%, p < 0.05), irrespectively of season. We identified ten V. cholerae O1 among 22 ctxA-positive isolates. Further studies are needed to serotype the remaining ctxA-positive non-O1 strains. Sequenced strains belonged to El Tor atypical biotype of V. cholerae O1 of MLST ST69 harboring the seventh pandemic gene. Major virulence genes, ctxA, ctxB, zot, ace, tcpA, hlyA, rtxA, ompU, toxR, T6SS, alsD, makA and pathogenicity islands VPI-1, VPI-2, VSP-1, and VSP-2 were found in all strains. The strains contained Vibrio polysaccharide biosynthesis enzymes, the mshA gene and two-component response regulator proteins involved in stress response and autoinducers for quorum sensing and biofilm formation. They carried the SXT integrative conjugative element with phenotypic and genotypic resistance to aminoglycoside, sulfamethoxazole, trimethoprim, phenicol, and quinolones. Strains contained a multidrug efflux pump component and were resistant to toxic compounds with copper homeostasis and cobalt-zinc-cadmium resistance proteins. The environmental strains belonged to the third wave of the seventh pandemic and most are genetically closely related to recent outbreak strains from Tanzania, Kenya, and Uganda with as low as three SNPs difference. Some strains have persisted longer in the environment and were more related to older outbreak strains in the region. V. cholerae O1 of outbreak potential seem to persist in Lake Victoria through interactions with fish and phytoplankton supported by the optimum water parameters and intrinsic genetic features enhancing survival in the aquatic environment.}, }
@article {pmid31114015, year = {2019}, author = {Worrich, A and Musat, N and Harms, H}, title = {Associational effects in the microbial neighborhood.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0444-6}, pmid = {31114015}, issn = {1751-7370}, abstract = {Even though &quot;perfect&quot; metagenomes or metatranscriptomes are close at hand, the implicit assumption of spatial homogeneity in the &quot;omic&quot; approaches makes it difficult if not impossible to relate those data to ecological processes occurring in natural and man-made ecosystems. In fact, the distribution of microbes in their habitats is far from being uniform and random. Microbial communities show a high degree of spatial organization that stems from environmental gradients and local interactions. These interactions can be very complex and may involve multiple species. Several studies highlighted the importance of indirect interactions for community stability, but the absence of a theoretical framework for microbial ecology restricts the possibilities to strike a balance between the investigation of simple communities with purely pairwise interactions and the attempts to understand interaction patterns in whole communities based on meta-omics studies. Here we suggest adapting the concept of Associational Effects (AE) from plant ecology, to better understand the link between ecological interactions, spatial arrangement, and stability in microbial communities. By bringing together a conceptual framework developed for plants and observations made for microbes, this perspective article fosters synthesis of related disciplines to yield novel insights into the advancing field of spatial microbial ecology. To promote the integration into microbial ecology, we (i) outline the theoretical background of AE, (ii) collect underlying mechanisms by literature synthesis, (iii) propose a three-point roadmap for the investigation of AE in microbial communities, and (iv) discuss its implications for microbial ecology research.}, }
@article {pmid31112792, year = {2019}, author = {Michels, N and Van de Wiele, T and Fouhy, F and O'Mahony, S and Clarke, G and Keane, J}, title = {Gut microbiome patterns depending on children's psychosocial stress: Reports versus biomarkers.}, journal = {Brain, behavior, and immunity}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.bbi.2019.05.024}, pmid = {31112792}, issn = {1090-2139}, abstract = {AIM: Chronic stress increases disease vulnerability factors including inflammation, a pathological characteristic potentially regulated by the gut microbiota. We checked the association between the gut microbiome and psychosocial stress in children/adolescents and investigated which stress parameter (negative versus positive emotion, self-report versus parental report, events versus emotions, biomarker cortisol versus parasympathetic activity) is the most relevant indicator herein.<br><br>METHODS: Gut microbiome sequencing was completed in fecal samples from 93 Belgian 8-16y olds. Stress measures included negative events, negative emotions, emotional problems reported by parents, happiness, hair cortisol and heart rate variability (pnn50 parameter reflecting parasympathetic activity). Alpha diversity, beta diversity and linear discriminant analysis were the unadjusted analyses. Age, sex, socio-economic status, diet, physical activity, sleep and weight status were adjusted for via a redundancy analysis and differential abundance via zero-inflated negative binomial regression.<br><br>RESULTS: High stress as reflected by low pnn50 and more negative events were associated with a lower alpha diversity as indicated by the Simpson index. Happiness and pnn50 showed significant differences between high and low stress groups based on weighted UniFrac distance, and this remained significant after confounder adjustment. Adjusted and unadjusted taxonomic differences were also most pronounced for happiness and pnn50 being associated respectively with 24 OTU (=11.8% of bacterial counts) and 31 OTU (=13.0%). As a general pattern, high stress was associated with lower Firmicutes at the phylum level and higher Bacteroides, Parabacteroides, Rhodococcus, Methanobrevibacter and Roseburia but lower Phascolarctobacterium at genus level. Several genera gave conflicting results between different stress measures e.g. Ruminococcaceae UCG014, Tenericutes, Eubacterium coprostanoligenes, Prevotella 9 and Christensenellaceae R7. Differential results in preadolescents versus adolescents were also evident.<br><br>CONCLUSION: Even in this young healthy population, stress parameters were cross-sectionally associated with gut microbial composition but this relationship was instrument specific. Positive emotions and parasympathetic activity appeared the strongest parameters and should be integrated in future microbiota projects amongst other stress measures.}, }
@article {pmid31111178, year = {2019}, author = {Mesquita, MCB and Prestes, ACC and Gomes, AMA and Marinho, MM}, title = {Direct Effects of Temperature on Growth of Different Tropical Phytoplankton Species.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01384-w}, pmid = {31111178}, issn = {1432-184X}, support = {478440/2011-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {Temperature increase may influence competition among phytoplankton species, potentially intensifying cyanobacteria blooms that can be favored by direct and indirect effects of temperature. In this study, we aimed to clarify how cyanobacteria can be favored by the direct effects of increased temperature compared to diatoms and chlorophytes. Strains of the most representative species of a eutrophic coastal lagoon (Microcystis aeruginosa, Planktothrix agardhii, Desmodesmus communis, and Cyclotella meneghiniana) were used to test the hypothesis that cyanobacteria would be favored by the direct effect of temperature increase. First, we evaluated the effect of temperature increase on growth in monocultures (batch and chemostats) at 25 and 30 °C and after in mixed cultures (chemostats). In batch monocultures, the cyanobacteria showed higher growth rates in 30 °C than in 25 °C. However, in continuous culture experiments (chemostats), growth rates of M. aeruginosa and P. agardhii were not affected by temperature, but the strains showed higher biovolume in steady-state with the temperature increase. In continuous mixed cultures, M. aeruginosa was always dominant and C. meneghiniana was excluded, regardless of temperature tested. D. communis was able to coexist with lower biomass. This study shows that rising temperatures can be detrimental to diatoms, even for a tropical strain. Although some studies indicate that the dominance of cyanobacteria in warmer climates may be due to the indirect effect of warming that will promote physical conditions in the environment more favorable to cyanobacteria, the outcomes of mixed cultures demonstrate that the direct effect of temperature can also favor the dominance of cyanobacteria.}, }
@article {pmid31110670, year = {2019}, author = {Silva, DP and Duarte, G and Villela, HDM and Santos, HF and Rosado, PM and Rosado, JG and Rosado, AS and Ferreira, EM and Soriano, AU and Peixoto, RS}, title = {Adaptable mesocosm facility to study oil spill impacts on corals.}, journal = {Ecology and evolution}, volume = {9}, number = {9}, pages = {5172-5185}, doi = {10.1002/ece3.5095}, pmid = {31110670}, issn = {2045-7758}, abstract = {Although numerous studies have been carried out on the impacts of oil spills on coral physiology, most have relied on laboratory assays. This scarcity is partly explained by the difficulty of reproducing realistic conditions in a laboratory setting or of performing experiments with toxic compounds in the field. Mesocosm systems provide the opportunity to carry out such studies with safe handling of contaminants while reproducing natural conditions required by living organisms. The mesocosm design is crucial and can lead to the development of innovative technologies to mitigate environmental impacts. Therefore, this study aimed to develop a mesocosm system for studies simulating oil spills with several key advantages, including true replication and the use of gravity to control flow-through that reduces reliance on pumps that can clog thereby decreasing errors and costs. This adaptable system can be configured to (a) have continuous flow-through; (b) operate as an open or closed system; (c) be fed by gravity; (d) have separate mesocosm sections that can be used for individual and simultaneous experiments; and (e) simulate the migration of oil from ocean oil spills to the nearby reefs. The mesocosm performance was assessed with two experiments using the hydrocoral Millepora alcicornis and different configurations to simulate two magnitudes of oil spills. With few exceptions, physical and chemical parameters remained stable within replicates and within treatments throughout the experiments. Physical and chemical parameters that expressed change during the experiment were still within the range of natural conditions observed in Brazilian marine environments. The photosynthetic potential (Fv/Fm) of the algae associated with M. alcicornis decreased in response to an 1% crude-oil contamination, suggesting a successful delivery of the toxic contaminant to the targeted replicates. This mesocosm is customizable and adjustable for several types of experiments and proved to be effective for studies of oil spills.}, }
@article {pmid31109532, year = {2019}, author = {Qi, H and Wei, Z and Zhang, J and Zhao, Y and Wu, J and Gao, X and Liu, Z and Li, Y}, title = {Effect of MnO2 on biotic and abiotic pathways of humic-like substance formation during composting of different raw materials.}, journal = {Waste management (New York, N.Y.)}, volume = {87}, number = {}, pages = {326-334}, doi = {10.1016/j.wasman.2019.02.022}, pmid = {31109532}, issn = {1879-2456}, abstract = {The humic-like substances (HLS) are proposed to be formed by biotic and abiotic pathways. The abiotic pathways were neglected in existed composting studies. The present study aims to accelerate the abiotic pathways, and to investigate how MnO2 drives the HLS transformation via changing the contribution of abiotic and biotic pathways during composting with different materials. Parallel factor analysis model (PARAFAC), hetero two-dimensional correlation spectra (hetero-2DCOS) and variance partitioning were used to identify the effects of MnO2 on the formation of humic acid (HA) and fluvic acid (FA) during composting of chicken manure (CM) and corn straw (CS). The addition of MnO2 could change the structures of HLS during CS and CM composting, mainly promoting the formation of complex components in HA and FA during CS composting, as well as the complex components of FA during CM composting. Meanwhile, the addition of MnO2 could reshape the microbial ecology, which enhanced the correlation between microbes and complex components formation during composting, especially in CM composting. Variance partitioning showed that both abiotic and biotic pathways were stimulated in conversion of HLS components after adding MnO2 during CS composting, especially for the abiotic pathways. During CM composting, the MnO2 promoted biotic effects on the conversion of HLS components. Above all, the addition of MnO2 could stimulate pathways of biotic, abiotic or both of them to improve the humification degree of HLS by changing microbial ecology, which could be a promising way for promoting the application value of composting products.}, }
@article {pmid31105660, year = {2019}, author = {Jørgensen, BB and Findlay, AJ and Pellerin, A}, title = {The Biogeochemical Sulfur Cycle of Marine Sediments.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {849}, doi = {10.3389/fmicb.2019.00849}, pmid = {31105660}, issn = {1664-302X}, abstract = {Microbial dissimilatory sulfate reduction to sulfide is a predominant terminal pathway of organic matter mineralization in the anoxic seabed. Chemical or microbial oxidation of the produced sulfide establishes a complex network of pathways in the sulfur cycle, leading to intermediate sulfur species and partly back to sulfate. The intermediates include elemental sulfur, polysulfides, thiosulfate, and sulfite, which are all substrates for further microbial oxidation, reduction or disproportionation. New microbiological discoveries, such as long-distance electron transfer through sulfide oxidizing cable bacteria, add to the complexity. Isotope exchange reactions play an important role for the stable isotope geochemistry and for the experimental study of sulfur transformations using radiotracers. Microbially catalyzed processes are partly reversible whereby the back-reaction affects our interpretation of radiotracer experiments and provides a mechanism for isotope fractionation. We here review the progress and current status in our understanding of the sulfur cycle in the seabed with respect to its microbial ecology, biogeochemistry, and isotope geochemistry.}, }
@article {pmid31100891, year = {2019}, author = {Jeong, Y and Kim, JW and You, HJ and Park, SJ and Lee, J and Ju, JH and Park, MS and Jin, H and Cho, ML and Kwon, B and Park, SH and Ji, GE}, title = {Gut Microbial Composition and Function Are Altered in Patients with Early Rheumatoid Arthritis.}, journal = {Journal of clinical medicine}, volume = {8}, number = {5}, pages = {}, doi = {10.3390/jcm8050693}, pmid = {31100891}, issn = {2077-0383}, support = {NRF-2017M3A9F3041045//National Research Foundation/ ; NRF-2017M3A9F3041747//National Research Foundation/ ; }, abstract = {Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation of the joints and extra-articular manifestations. Recent studies have shown that microorganisms affect RA pathogenesis. However, few studies have examined the microbial distribution of early RA patients, particularly female patients. In the present study, we investigated the gut microbiome profile and microbial functions in early RA female patients, including preclinical and clinically apparent RA cases. Changes in microbiological diversity, composition, and function in each group were analyzed using quantitative insights into microbial ecology (QIIME) and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). The results revealed the dysbiosis due to decreased diversity in the early RA patients compared with healthy subjects. There were significant differences in the microbial distribution of various taxa from phylum to genus levels between healthy subjects and early RA patients. Phylum Bacteroidetes was enriched in early RA patients, while Actinobacteria, including the genus Collinsella, was enriched in healthy subjects. Functional analysis based on clusters of orthologous groups revealed that the genes related to the biosynthesis of menaquinone, known to be derived from gram-positive bacteria, were enriched in healthy subjects, while iron transport-related genes were enriched in early RA patients. Genes related to the biosynthesis of lipopolysaccharide, the gram-negative bacterial endotoxin, were enriched in clinically apparent RA patients. The obvious differences in microbial diversity, taxa, and associated functions of the gut microbiota between healthy subjects and early RA patients highlight the involvement of the gut microbiome in the early stages of RA.}, }
@article {pmid31100615, year = {2019}, author = {Bautista-de Los Santos, QM and Chavarria, KA and Nelson, KL}, title = {Understanding the impacts of intermittent supply on the drinking water microbiome.}, journal = {Current opinion in biotechnology}, volume = {57}, number = {}, pages = {167-174}, doi = {10.1016/j.copbio.2019.04.003}, pmid = {31100615}, issn = {1879-0429}, abstract = {Increasing access to piped water in low-income and middle-income countries combined with the many factors that threaten our drinking water supply infrastructure mean that intermittent water supply (IWS) will remain a common practice around the world. Common features of IWS include water stagnation, pipe drainage, intrusion, backflow, first flush events, and household storage. IWS has been shown to cause degradation as measured by traditional microbial water quality indicators. In this review, we build on new insights into the microbial ecology of continuous water supply systems revealed by sequencing methods to speculate about how intermittent supply conditions may further influence the drinking water microbiome, and identify priorities for future research.}, }
@article {pmid31099963, year = {2019}, author = {Nguyen, B and Rubbens, P and Kerckhof, FM and Boon, N and De Baets, B and Waegeman, W}, title = {Learning Single-Cell Distances from Cytometry Data.}, journal = {Cytometry. Part A : the journal of the International Society for Analytical Cytology}, volume = {}, number = {}, pages = {}, doi = {10.1002/cyto.a.23792}, pmid = {31099963}, issn = {1552-4930}, support = {BOF15/DOS/039//Universiteit Gent/ ; BOFSTA2015000501//Universiteit Gent/ ; }, abstract = {Recent years have seen an increased interest in employing data analysis techniques for the automated identification of cell populations in the field of cytometry. These techniques highly depend on the use of a distance metric, a function that quantifies the distances between single-cell measurements. In most cases, researchers simply use the Euclidean distance metric. In this article, we exploit the availability of single-cell labels to find an optimal Mahalanobis distance metric derived from the data. We show that such a Mahalanobis distance metric results in an improved identification of cell populations compared with the Euclidean distance metric. Once determined, it can be used for the analysis of multiple samples that were measured under the same experimental setup. We illustrate this approach for cytometry data from two different origins, that is, flow cytometry applied to microbial cells and mass cytometry for the analysis of human blood cells. We also illustrate that such a distance metric results in an improved identification of cell populations when clustering methods are employed. Generally, these results imply that the performance of data analysis techniques can be improved by using a more advanced distance metric. © 2019 International Society for Advancement of Cytometry.}, }
@article {pmid31098412, year = {2019}, author = {Sato, Y and Hori, T and Koike, H and Navarro, RR and Ogata, A and Habe, H}, title = {Transcriptome analysis of activated sludge microbiomes reveals an unexpected role of minority nitrifiers in carbon metabolism.}, journal = {Communications biology}, volume = {2}, number = {}, pages = {179}, doi = {10.1038/s42003-019-0418-2}, pmid = {31098412}, issn = {2399-3642}, abstract = {Although metagenomics researches have illuminated microbial diversity in numerous biospheres, understanding individual microbial functions is yet difficult due to the complexity of ecosystems. To address this issue, we applied a metagenome-independent, de novo assembly-based metatranscriptomics to a complex microbiome, activated sludge, which has been used for wastewater treatment for over a century. Even though two bioreactors were operated under the same conditions, their performances differed from each other with unknown causes. Metatranscriptome profiles in high- and low-performance reactors demonstrated that denitrifiers contributed to the anaerobic degradation of heavy oil; however, no marked difference in the gene expression was found. Instead, gene expression-based nitrification activities that fueled the denitrifiers by providing the respiratory substrate were notably high in the high-performance reactor only. Nitrifiers-small minorities with relative abundances of <0.25%-governed the heavy-oil degradation performances of the reactors, unveiling an unexpected linkage of carbon- and nitrogen-metabolisms of the complex microbiome.}, }
@article {pmid31097577, year = {2019}, author = {Brumley, DR and Carrara, F and Hein, AM and Yawata, Y and Levin, SA and Stocker, R}, title = {Bacteria push the limits of chemotactic precision to navigate dynamic chemical gradients.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {22}, pages = {10792-10797}, doi = {10.1073/pnas.1816621116}, pmid = {31097577}, issn = {1091-6490}, abstract = {Ephemeral aggregations of bacteria are ubiquitous in the environment, where they serve as hotbeds of metabolic activity, nutrient cycling, and horizontal gene transfer. In many cases, these regions of high bacterial concentration are thought to form when motile cells use chemotaxis to navigate to chemical hotspots. However, what governs the dynamics of bacterial aggregations is unclear. Here, we use an experimental platform to create realistic submillimeter-scale nutrient pulses with controlled nutrient concentrations. By combining experiments, mathematical theory, and agent-based simulations, we show that individual Vibrio ordalii bacteria begin chemotaxis toward hotspots of dissolved organic matter (DOM) when the magnitude of the chemical gradient rises sufficiently far above the sensory noise that is generated by stochastic encounters with chemoattractant molecules. Each DOM hotspot is surrounded by a dynamic ring of chemotaxing cells, which congregate in regions of high DOM concentration before dispersing as DOM diffuses and gradients become too noisy for cells to respond to. We demonstrate that V. ordalii operates close to the theoretical limits on chemotactic precision. Numerical simulations of chemotactic bacteria, in which molecule counting noise is explicitly taken into account, point at a tradeoff between nutrient acquisition and the cost of chemotactic precision. More generally, our results illustrate how limits on sensory precision can be used to understand the location, spatial extent, and lifespan of bacterial behavioral responses in ecologically relevant environments.}, }
@article {pmid31095604, year = {2019}, author = {Di Lonardo, DP and de Boer, W and Zweers, H and van der Wal, A}, title = {Effect of the amount of organic trigger compounds, nitrogen and soil microbial biomass on the magnitude of priming of soil organic matter.}, journal = {PloS one}, volume = {14}, number = {5}, pages = {e0216730}, doi = {10.1371/journal.pone.0216730}, pmid = {31095604}, issn = {1932-6203}, abstract = {Priming effects (PEs) are defined as short-term changes in the turnover of soil organic matter (SOM) caused by the addition of easily degradable organic compounds to the soil. PEs are ubiquitous but the direction (acceleration or retardation of SOM decomposition) and magnitude are not easy to predict. It has been suggested that the ratio between the amount of added PE-triggering substrate to the size of initial soil microbial biomass is an important factor influencing PEs. However, this is mainly based on comparison of different studies and not on direct experimentation. The aim of the current study is to examine the impact of glucose-to-microbial biomass ratios on PEs for three different ecosystems. We did this by adding three different amounts of 13C-glucose with or without addition of mineral N (NH4NO3) to soils collected from arable lands, grasslands and forests. The addition of 13C-glucose was equivalent to 15%, 50% and 200% of microbial biomass C. After one month of incubation, glucose had induced positive PEs for almost all the treatments, with differences in magnitude related to the soil origin and the amount of glucose added. For arable and forest soils, the primed C increased with increasing amount of glucose added, whereas for grassland soils this relationship was negative. We found positive correlations between glucose-derived C and primed C and the strength of these correlations was different among the three ecosystems considered. Generally, additions of mineral N next to glucose (C:N = 15:1) had little effect on the flux of substrate-derived C and primed C. Overall, our study does not support the hypothesis that the trigger-substrate to microbial biomass ratio can be an important predictor of PEs. Rather our results indicate that the amount of energy obtained from decomposing trigger substrates is an important factor for the magnitude of PEs.}, }
@article {pmid31093727, year = {2019}, author = {Woodhams, DC and Rollins-Smith, LA and Reinert, LK and Lam, BA and Harris, RN and Briggs, CJ and Vredenburg, VT and Patel, BT and Caprioli, RM and Chaurand, P and Hunziker, P and Bigler, L}, title = {Probiotics Modulate a Novel Amphibian Skin Defense Peptide That Is Antifungal and Facilitates Growth of Antifungal Bacteria.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01385-9}, pmid = {31093727}, issn = {1432-184X}, support = {0640373//National Science Foundation/ ; 1121758//National Science Foundation/ ; 31-125099//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung/ ; }, abstract = {Probiotics can ameliorate diseases of humans and wildlife, but the mechanisms remain unclear. Host responses to interventions that change their microbiota are largely uncharacterized. We applied a consortium of four natural antifungal bacteria to the skin of endangered Sierra Nevada yellow-legged frogs, Rana sierrae, before experimental exposure to the pathogenic fungus Batrachochytrium dendrobatidis (Bd). The probiotic microbes did not persist, nor did they protect hosts, and skin peptide sampling indicated immune modulation. We characterized a novel skin defense peptide brevinin-1Ma (FLPILAGLAANLVPKLICSITKKC) that was downregulated by the probiotic treatment. Brevinin-1Ma was tested against a range of amphibian skin cultures and found to inhibit growth of fungal pathogens Bd and B. salamandrivorans, but enhanced the growth of probiotic bacteria including Janthinobacterium lividum, Chryseobacterium ureilyticum, Serratia grimesii, and Pseudomonas sp. While commonly thought of as antimicrobial peptides, here brevinin-1Ma showed promicrobial function, facilitating microbial growth. Thus, skin exposure to probiotic bacterial cultures induced a shift in skin defense peptide profiles that appeared to act as an immune response functioning to regulate the microbiome. In addition to direct microbial antagonism, probiotic-host interactions may be a critical mechanism affecting disease resistance.}, }
@article {pmid31093726, year = {2019}, author = {Hernández-Gómez, O and Wuerthner, V and Hua, J}, title = {Amphibian Host and Skin Microbiota Response to a Common Agricultural Antimicrobial and Internal Parasite.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01351-5}, pmid = {31093726}, issn = {1432-184X}, support = {1655190//Division of Environmental Biology/ ; 1708926//Directorate for Biological Sciences/ ; }, abstract = {Holistic approaches that simultaneously characterize responses of both microbial symbionts and their hosts to environmental shifts are imperative to understanding the role of microbiotas on host health. Using the northern leopard frog (Lithobates pipiens) as our model, we investigated the effects of a common trematode (family Echinostomatidae), a common agricultural antimicrobial (Sulfadimethoxine; SDM), and their interaction on amphibian skin microbiota and amphibian health (growth metrics and susceptibility to parasites). In the trematode-exposed individuals, we noted an increase in alpha diversity and a shift in microbial communities. In the SDM-treated individuals, we found a change in the composition of the skin microbiota similar to those induced by the trematode treatment. Groups treated with SDM, echinostomes, or a combination of SDM and echinostomes, had higher relative abundances of OTUs assigned to Flavobacterium and Acinetobacter. Both of these genera have been associated with infectious disease in amphibians and the production of anti-pathogen metabolites. Similar changes in microbial community composition between SDM and trematode exposed individuals may have resulted from stress-related disruption of host immunity. Despite changes in the microbiota, we found no effect of echinostomes and SDM on host health. Given the current disease- and pollution-related threats facing amphibians, our study highlights the need to continue to evaluate the influence of natural and anthropogenic stressors on host-associated microbial communities.}, }
@article {pmid31091418, year = {2019}, author = {Cordovez, V and Dini-Andreote, F and Carrión, VJ and Raaijmakers, JM}, title = {Ecology and Evolution of Plant Microbiomes.}, journal = {Annual review of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1146/annurev-micro-090817-062524}, pmid = {31091418}, issn = {1545-3251}, abstract = {Microorganisms colonizing plant surfaces and internal tissues provide a number of life-support functions for their host. Despite increasing recognition of the vast functional capabilities of the plant microbiome, our understanding of the ecology and evolution of the taxonomically hyperdiverse microbial communities is limited. Here, we review current knowledge of plant genotypic and phenotypic traits as well as allogenic and autogenic factors that shape microbiome composition and functions. We give specific emphasis to the impact of plant domestication on microbiome assembly and how insights into microbiomes of wild plant relatives and native habitats can contribute to reinstate or enrich for microorganisms with beneficial effects on plant growth, development, and health. Finally, we introduce new concepts and perspectives in plant microbiome research, in particular how community ecology theory can provide a mechanistic framework to unravel the interplay of distinct ecological processes-i.e., selection, dispersal, drift, diversification-that structure the plant microbiome. Expected final online publication date for the Annual Review of Microbiology Volume 73 is September 9, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.}, }
@article {pmid31088922, year = {2019}, author = {König, L and Wentrup, C and Schulz, F and Wascher, F and Escola, S and Swanson, MS and Buchrieser, C and Horn, M}, title = {Symbiont-Mediated Defense against Legionella pneumophila in Amoebae.}, journal = {mBio}, volume = {10}, number = {3}, pages = {}, doi = {10.1128/mBio.00333-19}, pmid = {31088922}, issn = {2150-7511}, abstract = {Legionella pneumophila is an important opportunistic pathogen for which environmental reservoirs are crucial for the infection of humans. In the environment, free-living amoebae represent key hosts providing nutrients and shelter for highly efficient intracellular proliferation of L. pneumophila, which eventually leads to lysis of the protist. However, the significance of other bacterial players for L. pneumophila ecology is poorly understood. In this study, we used a ubiquitous amoeba and bacterial endosymbiont to investigate the impact of this common association on L. pneumophila infection. We demonstrate that L. pneumophila proliferation was severely suppressed in Acanthamoeba castellanii harboring the chlamydial symbiont Protochlamydia amoebophila The amoebae survived the infection and were able to resume growth. Different environmental amoeba isolates containing the symbiont were equally well protected as different L. pneumophila isolates were diminished, suggesting ecological relevance of this symbiont-mediated defense. Furthermore, protection was not mediated by impaired L. pneumophila uptake. Instead, we observed reduced virulence of L. pneumophila released from symbiont-containing amoebae. Pronounced gene expression changes in the presence of the symbiont indicate that interference with the transition to the transmissive phase impedes the L. pneumophila infection. Finally, our data show that the defensive response of amoebae harboring P. amoebophila leaves the amoebae with superior fitness reminiscent of immunological memory. Given that mutualistic associations between bacteria and amoebae are widely distributed, P. amoebophila and potentially other amoeba endosymbionts could be key in shaping environmental survival, abundance, and virulence of this important pathogen, thereby affecting the frequency of human infection.IMPORTANCE Bacterial pathogens are generally investigated in the context of disease. To prevent outbreaks, it is essential to understand their lifestyle and interactions with other microbes in their natural environment. Legionella pneumophila is an important human respiratory pathogen that survives and multiplies in biofilms or intracellularly within protists, such as amoebae. Importantly, transmission to humans occurs from these environmental sources. Legionella infection generally leads to rapid host cell lysis. It was therefore surprising to observe that amoebae, including fresh environmental isolates, were well protected during Legionella infection when the bacterial symbiont Protochlamydia amoebophila was also present. Legionella was not prevented from invading amoebae but was impeded in its ability to develop fully virulent progeny and were ultimately cleared in the presence of the symbiont. This study highlights how ecology and virulence of an important human pathogen is affected by a defensive amoeba symbiont, with possibly major consequences for public health.}, }
@article {pmid31087742, year = {2019}, author = {Geiger, RA and Junghare, M and Mergelsberg, M and Ebenau-Jehle, C and Jesenofsky, VJ and Jehmlich, N and von Bergen, M and Schink, B and Boll, M}, title = {Enzymes involved in phthalate degradation in sulphate-reducing bacteria.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.14681}, pmid = {31087742}, issn = {1462-2920}, support = {BO 1565/16-1//German research council/ ; }, abstract = {The complete degradation of the xenobiotic and environmentally harmful phthalate esters is initiated by hydrolysis to alcohols and o-phthalate (phthalate) by esterases. While further catabolism of phthalate has been studied in aerobic and denitrifying microorganisms, the degradation in obligately anaerobic bacteria has remained obscure. Here, we demonstrate a previously overseen growth of the δ-proteobacterium Desulfosarcina cetonica with phthalate/sulphate as only carbon and energy sources. Differential proteome and CoA ester pool analyses together with in vitro enzyme assays identified the genes, enzymes and metabolites involved in phthalate uptake and degradation in D. cetonica. Phthalate is initially activated to the short-lived phthaloyl-CoA by an ATP-dependent phthalate CoA ligase (PCL) followed by decarboxylation to the central intermediate benzoyl-CoA by an UbiD-like phthaloyl-CoA decarboxylase (PCD) containing a prenylated flavin cofactor. Genome/metagenome analyses predicted phthalate degradation capacity also in the sulphate-reducing Desulfobacula toluolica, strain NaphS2, and other δ-proteobacteria. Our results suggest that phthalate degradation proceeds in all anaerobic bacteria via the labile phthaloyl-CoA that is captured and decarboxylated by highly abundant PCDs. In contrast, two alternative strategies have been established for the formation of phthaloyl-CoA, the possibly most unstable CoA ester in biology.}, }
@article {pmid31086312, year = {2019}, author = {Wu, L and Ning, D and Zhang, B and Li, Y and Zhang, P and Shan, X and Zhang, Q and Brown, M and Li, Z and Van Nostrand, JD and Ling, F and Xiao, N and Zhang, Y and Vierheilig, J and Wells, GF and Yang, Y and Deng, Y and Tu, Q and Wang, A and ,  and Zhang, T and He, Z and Keller, J and Nielsen, PH and Alvarez, PJJ and Criddle, CS and Wagner, M and Tiedje, JM and He, Q and Curtis, TP and Stahl, DA and Alvarez-Cohen, L and Rittmann, BE and Wen, X and Zhou, J}, title = {Global diversity and biogeography of bacterial communities in wastewater treatment plants.}, journal = {Nature microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41564-019-0426-5}, pmid = {31086312}, issn = {2058-5276}, abstract = {Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, the diversity of microorganisms and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analysed the 16S ribosomal RNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small, global core bacterial community (n = 28 operational taxonomic units) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal and drift), although deterministic factors (temperature and organic input) are also important. Our findings enhance our mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes.}, }
@article {pmid31079748, year = {2019}, author = {López, JC and Porca, E and Collins, G and Clifford, E and Quijano, G and Muñoz, R}, title = {Ammonium influences kinetics and structure of methanotrophic consortia.}, journal = {Waste management (New York, N.Y.)}, volume = {89}, number = {}, pages = {345-353}, doi = {10.1016/j.wasman.2019.04.028}, pmid = {31079748}, issn = {1879-2456}, abstract = {The literature is conflicted on the influence of ammonium on the kinetics and microbial ecology of methanotrophy. In this study, methanotrophic cultures were enriched, under ammonium concentrations ranging from 0 to 200 mM, from an inoculum comprising leachate and top-cover soil from a landfill. Specific CH4 biodegradation rates were highest (7.8 × 10-4 ± 6.0 × 10-5 gCH4 gX-1 h-1) in cultures enriched at 4 mM NH4+, which were mainly dominated by type II methanotrophs belonging to Methylocystis spp. Lower specific CH4 oxidation rates (average values of 1.8-3.6 × 10-4 gCH4 gX-1 h-1) were achieved by cultures enriched at higher NH4+ concentrations (20 and 80 mM), and had higher affinity for CH4 compared to 4 mM enrichments. These lower affinities were attributed to lower diversity dominated by type I methanotrophs, of the Methylosarcina, Methylobacter and Methylomicrobium genera, encountered with increasing concentrations of NH4+. The study indicates that CH4 oxidation biotechnologies applied at low NH4+ concentrations can support efficient abatement of CH4 and high diversity of methanotrophic consortia, whilst enriching type II methanotrophs.}, }
@article {pmid31079198, year = {2019}, author = {Wanner, M and Birkhofer, K and Fischer, T and Shimizu, M and Shimano, S and Puppe, D}, title = {Soil Testate Amoebae and Diatoms as Bioindicators of an Old Heavy Metal Contaminated Floodplain in Japan.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01383-x}, pmid = {31079198}, issn = {1432-184X}, support = {PU 626/2-1//Deutsche Forschungsgemeinschaft/ ; S16738//Japan Society for the Promotion of Science/ ; Kakenhi 15H02858//Japan Society for the Promotion of Science/ ; }, abstract = {Soil protists are rarely included in ecotoxicological investigations, despite their fundamental role in ecological processes. Moreover, testate amoebae and diatoms contribute considerably to silicon fluxes in soils. We investigated the effects of heavy metals on testate amoebae (species and individual densities) and diatoms (individual densities) in aged soils of a floodplain (Watarase retarding basin, Japan) taking soil samples from two unpolluted reference sites and two polluted sites. The total concentrations of Cu, Pb, and Zn in soil were higher at the polluted sites as compared with the reference sites. The available concentrations of Co, Cu, and Zn in CaCl2 extracts were higher at the polluted sites but available Pb was not detectable. Testate amoeba taxonomic richness was higher in the reference sites (45/38 taxa) than in the polluted sites (36/27 taxa). The reference sites had higher diatom and amoeba densities than the polluted sites. There was a significant negative correlation between total testate amoeba density and heavy metal concentration (available Co), while significant negative correlations were found between diatom density and Co, Cu, and Zn (available and total concentration). Densities of Cyclopyxis kahli cyclostoma, Centropyxis spp., and Trinema complanatum were negatively correlated to concentrations of available heavy metals. The observed decrease in individual numbers due to heavy metal pollution resulted in a considerable decline in protozoic (testate amoebae) and protophytic (pennate diatoms) silicon pools. Our data suggest that heavy metal pollution affects biogeochemical cycling in this system.}, }
@article {pmid31079197, year = {2019}, author = {Pillot, G and Davidson, S and Auria, R and Combet-Blanc, Y and Godfroy, A and Liebgott, PP}, title = {Production of Current by Syntrophy Between Exoelectrogenic and Fermentative Hyperthermophilic Microorganisms in Heterotrophic Biofilm from a Deep-Sea Hydrothermal Chimney.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01381-z}, pmid = {31079197}, issn = {1432-184X}, support = {PEPS-ExoMod 2016//Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique/ ; 1166-39417//European Regional Development Fund/ ; }, abstract = {To study the role of exoelectrogens within the trophic network of deep-sea hydrothermal vents, we performed successive subcultures of a hyperthermophilic community from a hydrothermal chimney sample on a mix of electron donors in a microbial fuel cell system. Electrode (the electron acceptor) was swapped every week to enable fresh development from spent media as inoculum. The MFC at 80 °C yielded maximum current production increasing from 159 to 247 mA m-2 over the subcultures. The experiments demonstrated direct production of electric current from acetate, pyruvate, and H2 and indirect production from yeast extract and peptone through the production of H2 and acetate from fermentation. The microorganisms found in on-electrode communities were mainly affiliated to exoelectrogenic Archaeoglobales and Thermococcales species, whereas in liquid media, the communities were mainly affiliated to fermentative Bacillales and Thermococcales species. The work shows interactions between fermentative microorganisms degrading complex organic matter into fermentation products that are then used by exoelectrogenic microorganisms oxidizing these reduced compounds while respiring on a conductive support. The results confirmed that with carbon cycling, the syntrophic relations between fermentative microorganisms and exoelectrogens could enable some microbes to survive as biofilm in extremely unstable conditions. Graphical Abstract Schematic representation of cross-feeding between fermentative and exoelectrogenic microbes on the surface of the conductive support. B, Bacillus/Geobacillus spp.; Tc, Thermococcales; Gg, Geoglobus spp.; Py, pyruvate; Ac, acetate.}, }
@article {pmid31074596, year = {2019}, author = {Feng, M and Tripathi, BM and Shi, Y and Adams, JM and Zhu, YG and Chu, H}, title = {Interpreting distance-decay pattern of soil bacteria via quantifying the assembly processes at multiple spatial scales.}, journal = {MicrobiologyOpen}, volume = {}, number = {}, pages = {e851}, doi = {10.1002/mbo3.851}, pmid = {31074596}, issn = {2045-8827}, support = {XDB15010101//Strategic Priority Research Program of the Chinese Academy of Sciences/ ; 2017YFC0504002//National Key Research and Development Program of China/ ; 2017YFD0200604//National Key Research and Development Program of China/ ; //China Biodiversity Observation Networks (Sino BON)/ ; }, abstract = {It has been widely accepted that there is a distance-decay pattern in the soil microbiome. However, few studies have attempted to interpret the microbial distance-decay pattern from the perspective of quantifying underlying processes. In this study, we examined the processes governing bacterial community assembly at multiple spatial scales in maize fields of Northeast China using Illumina MiSeq sequencing. Results showed that the processes governing spatial turnover in bacterial community composition shifted regularly with spatial scale, with homogenizing dispersal dominating at small spatial scales and variable selection dominating at larger scales, which in turn explained the distance-decay pattern that closer located sites tended to have higher community similarity. Together, homogenizing dispersal and dispersal limitation resulting from geographic factors governed about 33% of spatial turnover in bacterial community composition. Deterministic selection processes had the strongest influence, at 57%, with biotic factors and abiotic environmental filtering (mainly imposed by soil pH) respectively contributing about 37% and 63% of variation. Our results provided a novel and comprehensive way to explain the distance-decay pattern of soil microbiome via quantifying the assembly processes at multiple spatial scales, as well as the method to quantify the influence of abiotic, biotic, and geographic factors in shaping microbial community structure, thus enabling understanding of widely acknowledged microbial biogeographic patterns and microbial ecology.}, }
@article {pmid31065700, year = {2019}, author = {Mohammed, AA and Jiang, S and Jacobs, JA and Cheng, HW}, title = {Effect of a synbiotic supplement on cecal microbial ecology, antioxidant status, and immune response of broiler chickens reared under heat stress.}, journal = {Poultry science}, volume = {}, number = {}, pages = {}, doi = {10.3382/ps/pez246}, pmid = {31065700}, issn = {1525-3171}, abstract = {The aim of this study was to examine the effect of a dietary synbiotic supplement on the cecal microflora, antioxidant status, and immune response of broiler chickens under heat stress (HS). A total of 360 one-day-old male Ross 708 broiler chicks were randomly distributed among 3 dietary treatments containing a synbiotic (PoultryStar consists of Bifidobacterium animalis, Enterococcus faecium, Lactobacillus reuteri, Pediococcus acidilactici, and fructooligosaccharides) at 0 (control), 0.5 (0.5X), and 1.0 (1.0X) g/kg. Each treatment contained 8 replicates of 15 birds each housed in floor pens. Heat stimulation was at 32°C for 9 h daily from day 15 to 42. Heat stress-induced changes of cecal bacteria were detected using bacteria-specific agars, and spleen protein concentration and mRNA expression of interleukins and antioxidants were examined using ELISA and real-time PCR, respectively. Under the HS condition, synbiotic fed broilers regardless of dose had lower cecal enumerations of Escherichia coli and coliforms, and a lower heterophil/lymphocyte (H/L) ratio (P < 0.05) compared to controls. 1.0X group also had higher cecal enumerations of Bifidobacterium spp. and Lactobacillus spp., spleen glutathione peroxidase (GPx), and plasma nuclear factor erythroid 2-related factor 2 (Nrf-2), and a lower H/L ratio compared to both control and 0.5X groups (P < 0.05). However, there were no treatment effects on the levels of Enterococcus spp., the circulating monocytes, eosinophils, and basophils, Toll like receptor-4 (TLR-4), interleukin-6 (IL-6), interlukin-10 (IL-10), and their mRNA expression, as well as plasma Kelch-like ECH-associated protein 1 (Keap-1) (P > 0.05). These results suggest that the synbiotic could inhibit the negative effects of HS on broiler health through the reduction of cecal pathogens, regulation of stress reactions, and improvement of antioxidant status.}, }
@article {pmid31064055, year = {2019}, author = {Pineda-Quiroga, C and Borda-Molina, D and Chaves-Moreno, D and Ruiz, R and Atxaerandio, R and Camarinha-Silva, A and García-Rodríguez, A}, title = {Microbial and Functional Profile of the Ceca from Laying Hens Affected by Feeding Prebiotics, Probiotics, and Synbiotics.}, journal = {Microorganisms}, volume = {7}, number = {5}, pages = {}, doi = {10.3390/microorganisms7050123}, pmid = {31064055}, issn = {2076-2607}, support = {LIFE11/ENV/ES/000639//LIFE program of the European Union/ ; PRE/2013/1/1077//Department of Education, Language Policy and Culture, Scholarship, , Basque Government, Vitoria-Gasteiz, Spain/ ; }, abstract = {Diet has an essential influence in the establishment of the cecum microbial communities in poultry, so its supplementation with safe additives, such as probiotics, prebiotics, and synbiotics might improve animal health and performance. This study showed the ceca microbiome modulations of laying hens, after feeding with dry whey powder as prebiotics, Pediococcus acidilactici as probiotics, and the combination of both as synbiotics. A clear grouping of the samples induced per diet was observed (p < 0.05). Operational taxonomic units (OTUs) identified as Olsenella spp., and Lactobacilluscrispatus increased their abundance in prebiotic and synbiotic treatments. A core of the main functions was shared between all metagenomes (45.5%), although the genes encoding for the metabolism of butanoate, propanoate, inositol phosphate, and galactose were more abundant in the prebiotic diet. The results indicated that dietary induced-changes in microbial composition did not imply a disturbance in the principal biological roles, while the specific functions were affected.}, }
@article {pmid31063726, year = {2019}, author = {Lindemann, SR}, title = {Microbial Ecology: Functional 'Modules' Drive Assembly of Polysaccharide-Degrading Marine Microbial Communities.}, journal = {Current biology : CB}, volume = {29}, number = {9}, pages = {R330-R332}, doi = {10.1016/j.cub.2019.03.056}, pmid = {31063726}, issn = {1879-0445}, abstract = {Although ecological principles governing the competition of microbes for simple substrates are well-understood, less is known about how complex, structured substrates influence ecological outcomes in microbial communities. A new study sheds light on how marine microbial communities assemble on polysaccharide particles modeling marine snow.}, }
@article {pmid31060399, year = {2019}, author = {Panebianco, C and Pazienza, V}, title = {Body site-dependent variations of microbiota in pancreatic cancer pathophysiology.}, journal = {Critical reviews in clinical laboratory sciences}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/10408363.2019.1615407}, pmid = {31060399}, issn = {1549-781X}, abstract = {Lack of specific symptoms and reliable biomarkers, along with aggressive nature and resistance to therapies makes pancreatic cancer (PC) one of the leading causes of death from cancer worldwide. The search for new diagnostic, prognostic, predictive, and therapeutic tools that could improve clinical outcomes of patients has led, in recent years, to the investigation of potential roles for the microbiota in the pathogenesis of this disease. The human microbiota encompasses trillions of microorganisms residing within several body tissues and organs, where they provide beneficial functions for host homeostasis and health. Derangements of the microbial ecology in different anatomic districts have been described in PC, as in many other diseases, both in patients and in animal models. In detail, infection from the gastric pathogen Helicobacter pylori and changes in composition and diversity of oral, intestinal, and pancreatic microbiota have been found to associate with PC. Future research should assess how to potentially exploit such differences in microbiota composition as diagnostic, prognostic, or predictive biomarkers, and as targets for therapeutic interventions, in the hope of improving the dismal prognosis of this insidious cancer.}, }
@article {pmid31058277, year = {2018}, author = {Photos-Jones, E}, title = {From mine to apothecary: an archaeo-biomedical approach to the study of the Greco-Roman lithotherapeutics industry.}, journal = {World archaeology}, volume = {50}, number = {3}, pages = {418-433}, doi = {10.1080/00438243.2018.1515034}, pmid = {31058277}, issn = {0043-8243}, abstract = {Western biomedicine has only partially developed its own tradition of mineral medicinals (lithotherapeutics), at least compared to botanicals. This is perhaps because these minerals were site-specific, and fundamental information associated with the empirical processes of mineral extraction, beneficiation, storage, trade and preparation was not widely available. In other words, there are many and serious breaks in the multi-link chain from mine to apothecary. This long-term investigation aims to rebuild this chain, on a mineral-by-mineral basis, by pulling together the extant documentary record, material culture, mineralogy, geochemistry and microbial ecology, as well as by testing against known pathogens as an indicator of their antimicrobial activity. Critical to understanding the nature and efficacy of lithotherapeutics is the recognition that these materials need to be investigated simultaneously at two levels: the empirical (ancient sources and practices); and the biomedical (application of physical and biological sciences). Both approaches require the same starting point, namely the field (mine or quarry) and in particular the 'point of contact' (relationship) between minerals and their microbiome.}, }
@article {pmid31055618, year = {2019}, author = {Ben Yahia, H and Chairat, S and Gharsa, H and Alonso, CA and Ben Sallem, R and Porres-Osante, N and Hamdi, N and Torres, C and Ben Slama, K}, title = {First Report of KPC-2 and KPC-3-Producing Enterobacteriaceae in Wild Birds in Africa.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01375-x}, pmid = {31055618}, issn = {1432-184X}, abstract = {The increased incidence of antibiotic-resistant Enterobacteriaceae is a public health problem worldwide. The aim of this study was to analyze the potential role of wild birds, given their capacity of migrating over long distances, in the spreading of carbapenemase, extended-spectrum β-lactamase (ESBL), and acquired-AmpC beta-lactamase-producing Enterobacteriaceae in the environment. Fecal and pellet samples were recovered from 150 wild birds in seven Tunisian regions and were inoculated in MacConkey-agar plates for Enterobacteriaceae recovery (one isolate/animal). Ninety-nine isolates were obtained and acquired resistance mechanisms were characterized in the five detected imipenem-resistant and/or cefotaxime-resistant isolates, by PCR and sequencing. The following ESBL, carbapenemase, and acquired-AmpC beta-lactamase genes were detected: blaCTX-M-15 (two Escherichia fergusonii and one Klebsiella oxytoca isolates), blaKPC-2 (one K. oxytoca), blaKPC-3 (one E. fergusonii), blaACT-36, and blaACC-2 (two K. oxytoca, four E. fergusonii, and two E. coli). The IncFIIs, IncF, IncFIB, IncK, IncP, and IncX replicons were detected among these beta-lactamase Enterobacteriaceae producers. The blaKPC-2, tetA, sul3, qnrB, and cmlA determinants were co-transferred by conjugation from K. oxytoca strain to E. coli J153, in association with IncK and IncF replicons. Our results support the implication of wild birds as a biological vector for carbapenemase, ESBL, and acquired-AmpC-producing Enterobacteriaceae.}, }
@article {pmid31054240, year = {2019}, author = {Ma, S and De Frenne, P and Boon, N and Brunet, J and Cousins, SAO and Decocq, G and Kolb, A and Lemke, I and Liira, J and Naaf, T and Orczewska, A and Plue, J and Wulf, M and Verheyen, K}, title = {Plant species identity and soil characteristics determine rhizosphere soil bacteria community composition in European temperate forests.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {6}, pages = {}, doi = {10.1093/femsec/fiz063}, pmid = {31054240}, issn = {1574-6941}, abstract = {Soil bacteria and understorey plants interact and drive forest ecosystem functioning. Yet, knowledge about biotic and abiotic factors that affect the composition of the bacterial community in the rhizosphere of understorey plants is largely lacking. Here, we assessed the effects of plant species identity (Milium effusum vs. Stachys sylvatica), rhizospheric soil characteristics, large-scale environmental conditions (temperature, precipitation and nitrogen (N) deposition), and land-use history (ancient vs. recent forests) on bacterial community composition in rhizosphere soil in temperate forests along a 1700 km latitudinal gradient in Europe. The dominant bacterial phyla in the rhizosphere soil of both plant species were Acidobacteria, Actinobacteria and Proteobacteria. Bacterial community composition differed significantly between the two plant species. Within plant species, soil chemistry was the most important factor determining soil bacterial community composition. More precisely, soil acidity correlated with the presence of multiple phyla, e.g. Acidobacteria (negatively), Chlamydiae (negatively) and Nitrospirae (positively), in both plant species. Large-scale environmental conditions were only important in S. sylvatica and land-use history was not important in either of the plant species. The observed role of understorey plant species identity and rhizosphere soil characteristics in determining soil bacterial community composition extends our understanding of plant-soil bacteria interactions in forest ecosystem functioning.}, }
@article {pmid31053974, year = {2019}, author = {Krstin, L and Katanić, Z and Repar, J and Ježić, M and Kobaš, A and Ćurković-Perica, M}, title = {Genetic Diversity of Cryphonectria hypovirus 1, a Biocontrol Agent of Chestnut Blight, in Croatia and Slovenia.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01377-9}, pmid = {31053974}, issn = {1432-184X}, support = {IZ73Z0_152525/1//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung/ ; IZIP-2016-54//Sveučilište Josipa Jurja Strossmayera u Osijeku/ ; }, abstract = {Transmissible hypovirulence associated with Cryphonectria hypovirus 1 (CHV1) has been used for biological control of chestnut blight, devastating disease of chestnut caused by the fungus Cryphonectria parasitica. The main aims of this study were to provide molecular characterization of CHV1 from Croatia and Slovenia and to reveal its genetic variability, phylogeny, and diversification of populations. Fifty-one CHV1 haplotypes were detected among 54 partially sequenced CHV1 isolates, all belonging to Italian subtype (I). Diversity was mainly generated by point mutations while evidence of recombination was not found. The level of conservation over analyzed parts of ORF-A proteins p29 and p40 varied, but functional sites were highly conserved. Phylogenetic analysis revealed close relatedness and intermixing of Croatian and Slovenian CHV1 populations. Our CHV1 isolates were also related to Swiss and Bosnian hypoviruses supporting previously suggested course of CHV1 invasion in Europe. Overall, this study indicates that phylogeny of CHV1 subtype I in Europe is complex and characterized with frequent point mutations resulting in many closely related variants of the virus. Possible association between variations within CHV1 ORF-A and growth of the hypovirulent fungal isolates is tested and presented.}, }
@article {pmid31050730, year = {2019}, author = {Moraïs, S and Mizrahi, I}, title = {Islands in the stream: from individual to communal fiber degradation in the rumen ecosystem.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuz007}, pmid = {31050730}, issn = {1574-6976}, abstract = {The herbivore rumen ecosystem constitutes an extremely efficient degradation machinery for the intricate chemical structure of fiber biomass, thus, enabling the hosting animal to digest its feed. The challenging task of deconstructing and metabolizing fiber is performed by microorganisms inhabiting the rumen. Since most of the ingested feed is comprised of plant fiber, these fiber-degrading microorganisms are of cardinal importance to the ecology of the rumen microbial community and to the hosting animal, and have a great impact on our environment and food sustainability. We summarize herein the enzymological fundamentals of fiber degradation, how the genes encoding these enzymes are spread across fiber-degrading microbes, and these microbes' interactions with other members of the rumen microbial community and potential effect on community structure. An understanding of these concepts has applied value for agriculture and our environment, and will also contribute to a better understanding of microbial ecology and evolution in anaerobic ecosystems.}, }
@article {pmid31050668, year = {2019}, author = {Melo-Bolívar, JF and Ruiz Pardo, RY and Hume, ME and Nisbet, DJ and Rodríguez-Villamizar, F and Alzate, JF and Junca, H and Villamil Díaz, LM}, title = {Establishment and characterization of a competitive exclusion bacterial culture derived from Nile tilapia (Oreochromis niloticus) gut microbiomes showing antibacterial activity against pathogenic Streptococcus agalactiae.}, journal = {PloS one}, volume = {14}, number = {5}, pages = {e0215375}, doi = {10.1371/journal.pone.0215375}, pmid = {31050668}, issn = {1932-6203}, abstract = {This study reports the characterization of the microbial community composition, and the establishment and dynamics of a continuous-flow competitive exclusion culture (CFCEC) derived from gut microbiomes of Nile tilapia (Oreochromis niloticus) specimens reared on aquaculture farms in Colombia. 16S rRNA gene amplicon Illumina sequencing was used to identify taxonomical changes in the CFCEC microbial community over time. The CFCEC was developed from adult tilapia from two farms in Colombia, and CFCEC samples were collected over two months. The pH varied from 6.25 to 6.35 throughout culturing, while anaerobic and aerobic cell counts stabilized at day 9, at 109 CFU mL-1 and were maintained to day 68. A variation in the CFCEC bacterial composition was observed over time. Cetobacterium was the most abundant in the first two days and coincided with a higher CFCEC supernatant antimicrobial effect against the fish pathogen Streptococcus agalactiae. Antimicrobial activity against S. agalactiae disappeared by day 3. Changes in bacterial composition continued to day 33 with Lactococcus spp. becoming the most abundant member of the community. In conclusion, the study of the CFCEC from intestinal tract of Nile tilapia (Oreochromis niloticus) by 16S rRNA gene sequencing allowed identification of predominant bacterial genera in the continuous-flow competitive exclusion culture exhibiting antibacterial activity against the fish pathogen Streptococcus agalactiae.}, }
@article {pmid31049616, year = {2019}, author = {Ma, GC and Worthing, KA and Ward, MP and Norris, JM}, title = {Commensal Staphylococci Including Methicillin-Resistant Staphylococcus aureus from Dogs and Cats in Remote New South Wales, Australia.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01382-y}, pmid = {31049616}, issn = {1432-184X}, abstract = {Staphylococci are important opportunistic pathogens in human and veterinary medicine in addition to being part of the normal flora of the skin and mucous membranes of mammals and birds. The rise of antimicrobial resistance amongst staphylococci warrants closer investigation of the diversity of skin commensal organisms-including coagulase-negative staphylococci (CoNS)-due to their potential as a source of resistance genes. This study is aimed at characterising the commensal staphylococci-including methicillin-resistant Staphylococcus species (spp.)-from mucocutaneous sites of dogs and cats from remote New South Wales (NSW), Australia. Pet dogs and cats were recruited from participants in a community companion animal health programme in six communities in western NSW. Three swabs were collected from each animal (anterior nares, oropharynx, and perineum) and from skin lesions or wounds if present and cultured on selective media for Staphylococcus spp. In total, 383 pets (303 dogs, 80 cats) were enrolled. Staphylococcus spp. were isolated from 67.3% of dogs and 73.8% of cats (494 isolates). The diversity of CoNS was high (20 species) whilst only three coagulase-positive spp. were isolated (S. pseudintermedius, S. aureus, S. intermedius). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in dogs was high (2.6%) relative to other studies but was only a small proportion of overall commensal staphylococci. No cats carried MRSA and no MRSP was isolated from either species. Dogs were significantly more likely to carry coagulase-positive staphylococci than cats (P < 0.001). Amongst dogs, males and those with skin lesions were more likely to carry S. pseudintermedius. This study highlights important differences in the diversity and patterns of carriage of commensal staphylococci between dogs and cats in remote NSW, Australia.}, }
@article {pmid31049565, year = {2019}, author = {Samba-Louaka, A and Delafont, V and Rodier, MH and Cateau, E and Héchard, Y}, title = {Free-living amoebae and squatters in the wild: ecological and molecular features.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuz011}, pmid = {31049565}, issn = {1574-6976}, abstract = {Free-living amoebae are protists frequently found in water and soils. They feed on other microorganisms, mainly bacteria, and digest them through phagocytosis. It is accepted that these amoebae play an important role in the microbial ecology of these environments. There is a renewed interest for the free-living amoebae since the discovery of pathogenic bacteria that can resist phagocytosis and of giant viruses, underlying that amoebae might play a role in the evolution of other microorganisms, including several human pathogens. Recent advances, using molecular methods, allow to bring together new information about free-living amoebae. This review aims to provide a comprehensive overview of the newly gathered insights into 1) the free-living amoeba diversity, assessed with molecular tools 2) the gene functions described to decipher the biology of the amoebae and 3) their interactions with other microorganisms in the environment.}, }
@article {pmid31048756, year = {2019}, author = {Schwank, K and Bornemann, TLV and Dombrowski, N and Spang, A and Banfield, JF and Probst, AJ}, title = {An archaeal symbiont-host association from the deep terrestrial subsurface.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0421-0}, pmid = {31048756}, issn = {1751-7370}, abstract = {DPANN archaea have reduced metabolic capacities and are diverse and abundant in deep aquifer ecosystems, yet little is known about their interactions with other microorganisms that reside there. Here, we provide evidence for an archaeal host-symbiont association from a deep aquifer system at the Colorado Plateau (Utah, USA). The symbiont, Candidatus Huberiarchaeum crystalense, and its host, Ca. Altiarchaeum hamiconexum, show a highly significant co-occurrence pattern over 65 metagenome samples collected over six years. The physical association of the two organisms was confirmed with genome-informed fluorescence in situ hybridization depicting small cocci of Ca. H. crystalense attached to Ca. A. hamiconexum cells. Based on genomic information, Ca. H. crystalense potentially scavenges vitamins, sugars, nucleotides, and reduced redox-equivalents from its host and thus has a similar metabolism as Nanoarchaeum equitans. These results provide insight into host-symbiont interactions among members of two uncultivated archaeal phyla that thrive in a deep subsurface aquifer.}, }
@article {pmid31048390, year = {2019}, author = {Bryce, C and Blackwell, N and Straub, D and Kleindienst, S and Kappler, A}, title = {Draft Genome Sequence of Chlorobium sp. Strain N1, a Marine Fe(II)-Oxidizing Green Sulfur Bacterium.}, journal = {Microbiology resource announcements}, volume = {8}, number = {18}, pages = {}, doi = {10.1128/MRA.00080-19}, pmid = {31048390}, issn = {2576-098X}, abstract = {Here, we present the draft genome sequence of the halotolerant photoferrotroph Chlorobium sp. strain N1. This draft genome provides insights into the genomic potential of the only marine Fe(II)-oxidizing green sulfur bacterium (GSB) available in culture and expands our views on the metabolic capabilities of Fe(II)-oxidizing GSB more generally.}, }
@article {pmid31046835, year = {2019}, author = {Sharma, A and Richardson, M and Cralle, L and Stamper, CE and Maestre, JP and Stearns-Yoder, KA and Postolache, TT and Bates, KL and Kinney, KA and Brenner, LA and Lowry, CA and Gilbert, JA and Hoisington, AJ}, title = {Longitudinal homogenization of the microbiome between both occupants and the built environment in a cohort of United States Air Force Cadets.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {70}, doi = {10.1186/s40168-019-0686-6}, pmid = {31046835}, issn = {2049-2618}, support = {G-2016-7077//Alfred P. Sloan Foundation/ ; }, abstract = {BACKGROUND: The microbiome of the built environment has important implications for human health and wellbeing; however, bidirectional exchange of microbes between occupants and surfaces can be confounded by lifestyle, architecture, and external environmental exposures. Here, we present a longitudinal study of United States Air Force Academy cadets (n = 34), which have substantial homogeneity in lifestyle, diet, and age, all factors that influence the human microbiome. We characterized bacterial communities associated with (1) skin and gut samples from roommate pairs, (2) four built environment sample locations inside the pairs' dormitory rooms, (3) four built environment sample locations within shared spaces in the dormitory, and (4) room-matched outdoor samples from the window ledge of their rooms.<br><br>RESULTS: We analyzed 2,170 samples, which generated 21,866 unique amplicon sequence variants. Linear convergence of microbial composition and structure was observed between an occupants' skin and the dormitory surfaces that were only used by that occupant (i.e., desk). Conversely, bacterial community beta diversity (weighted Unifrac) convergence between the skin of both roommates and the shared dormitory floor between the two cadet's beds was not seen across the entire study population. The sampling period included two semester breaks in which the occupants vacated their rooms; upon their return, the beta diversity similarity between their skin and the surfaces had significantly decreased compared to before the break (p < 0.05). There was no apparent convergence between the gut and building microbiota, with the exception of communal bathroom door-handles, which suggests that neither co-occupancy, diet, or lifestyle homogenization had a significant impact on gut microbiome similarity between these cadets over the observed time frame. As a result, predictive classifier models were able to identify an individual more accurately based on the gut microbiota (74%) compared to skin (51%).<br><br>CONCLUSIONS: To the best of our knowledge, this is the first study to show an increase in skin microbial similarity of two individuals who start living together for the first time and who are not genetically related or romantically involved. Cohabitation was significantly associated with increased skin microbiota similarity but did not significantly influence the gut microbiota. Following a departure from the occupied space of several weeks, the skin microbiota, but not the gut microbiota, showed a significant reduction in similarity relative to the building. Overall, longitudinal observation of these dynamics enables us to dissect the influence of occupation, diet, and lifestyle factors on occupant and built environment microbial ecology.}, }
@article {pmid31040329, year = {2019}, author = {Engel, F and Attermeyer, K and Ayala, AI and Fischer, H and Kirchesch, V and Pierson, DC and Weyhenmeyer, GA}, title = {Phytoplankton gross primary production increases along cascading impoundments in a temperate, low-discharge river: Insights from high frequency water quality monitoring.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6701}, doi = {10.1038/s41598-019-43008-w}, pmid = {31040329}, issn = {2045-2322}, support = {2016-04153//Vetenskapsr&amp;#x00E5;det (Swedish Research Council)/ ; 643052//EC | Horizon 2020 (Horizon 2020 - Research and Innovation Framework Programme)/ ; KAW project//Knut och Alice Wallenbergs Stiftelse (Knut and Alice Wallenberg Foundation)/ ; }, abstract = {Damming alters carbon processing along river continua. Estimating carbon transport along rivers intersected by multiple dams requires an understanding of the effects of cascading impoundments on the riverine metabolism. We analyzed patterns of riverine metabolism and phytoplankton biomass (chlorophyll a; Chla) along a 74.4-km river reach intersected by six low-head navigation dams. Calculating gross primary production (GPP) from continuous measurements of dissolved oxygen concentration, we found a maximum increase in the mean GPP by a factor of 3.5 (absolute difference of 0.45 g C m-3 d-1) along the first 26.5 km of the study reach, while Chla increased over the entire reach by a factor of 2.9 (8.7 µg l-1). In the intermittently stratified section of the deepest impoundment the mean GPP between the 1 and 4 m water layer differed by a factor of 1.4 (0.31 g C m-3 d-1). Due to the strong increase in GPP, the river featured a wide range of conditions characteristic of low- to medium-production rivers. We suggest that cascading impoundments have the potential to stimulate riverine GPP, and conclude that phytoplankton CO2 uptake is an important carbon flux in the river Saar, where a considerable amount of organic matter is of autochthonous origin.}, }
@article {pmid31038352, year = {2019}, author = {Dong, Y and Sanford, RA and Inskeep, WP and Srivastava, V and Bulone, V and Fields, CJ and Yau, PM and Sivaguru, M and Ahrén, D and Fouke, KW and Weber, J and Werth, CR and Cann, IK and Keating, KM and Khetani, RS and Hernandez, AG and Wright, C and Band, M and Imai, BS and Fried, GA and Fouke, BW}, title = {Physiology, Metabolism, and Fossilization of Hot-Spring Filamentous Microbial Mats.}, journal = {Astrobiology}, volume = {}, number = {}, pages = {}, doi = {10.1089/ast.2018.1965}, pmid = {31038352}, issn = {1557-8070}, abstract = {The evolutionarily ancient Aquificales bacterium Sulfurihydrogenibium spp. dominates filamentous microbial mat communities in shallow, fast-flowing, and dysoxic hot-spring drainage systems around the world. In the present study, field observations of these fettuccini-like microbial mats at Mammoth Hot Springs in Yellowstone National Park are integrated with geology, geochemistry, hydrology, microscopy, and multi-omic molecular biology analyses. Strategic sampling of living filamentous mats along with the hot-spring CaCO3 (travertine) in which they are actively being entombed and fossilized has permitted the first direct linkage of Sulfurihydrogenibium spp. physiology and metabolism with the formation of distinct travertine streamer microbial biomarkers. Results indicate that, during chemoautotrophy and CO2 carbon fixation, the 87-98% Sulfurihydrogenibium-dominated mats utilize chaperons to facilitate enzyme stability and function. High-abundance transcripts and proteins for type IV pili and extracellular polymeric substances (EPSs) are consistent with their strong mucus-rich filaments tens of centimeters long that withstand hydrodynamic shear as they become encrusted by more than 5 mm of travertine per day. Their primary energy source is the oxidation of reduced sulfur (e.g., sulfide, sulfur, or thiosulfate) and the simultaneous uptake of extremely low concentrations of dissolved O2 facilitated by bd-type cytochromes. The formation of elevated travertine ridges permits the Sulfurihydrogenibium-dominated mats to create a shallow platform from which to access low levels of dissolved oxygen at the virtual exclusion of other microorganisms. These ridged travertine streamer microbial biomarkers are well preserved and create a robust fossil record of microbial physiological and metabolic activities in modern and ancient hot-spring ecosystems.}, }
@article {pmid31037377, year = {2019}, author = {Wu, C and Kan, J and Liu, H and Pujari, L and Guo, C and Wang, X and Sun, J}, title = {Heterotrophic Bacteria Dominate the Diazotrophic Community in the Eastern Indian Ocean (EIO) during Pre-Southwest Monsoon.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01355-1}, pmid = {31037377}, issn = {1432-184X}, support = {41276124//the National Natural Science Foundation of China/ ; 41676112//the National Natural Science Foundation of China/ ; NORC2017-10//NSFC open research cruises/ ; TD12-5003//the Science Fund for University Creative Research Groups in Tianjin/ ; 41876134//Foundation for the Author of National Excellent Doctoral Dissertation of the People's Republic of China (CN)/ ; }, abstract = {The diazotrophic communities play an important role in sustaining primary productivity through adding new nitrogen to oligotrophic marine ecosystems. Yet, their composition in the oligotrophic Indian Ocean is poorly understood. Here, we report the first observation of phylogenetic diversity and distribution of diazotrophs in the Eastern Indian Ocean (EIO) surface water (to 200 m) during the pre-southwest monsoon period. Through high throughput sequencing of nifH genes, we identified diverse groups of diazotrophs in the EIO including both non-cyanobacterial and cyanobacterial phylotypes. Proteobacteria (mainly Alpha-, Beta-, and Gamma-proteobacteria) were the most diverse and abundant groups within all the diazotrophs, which accounted for more than 86.9% of the total sequences. Cyanobacteria were also retrieved, and they were dominated by the filamentous non-heterocystous cyanobacteria Trichodesmium spp. Other cyanobacteria such as unicellular diazotrophic cyanobacteria were detected sporadically. Interestingly, our qPCR analysis demonstrated that the depth-integrated gene abundances of the diazotrophic communities exhibited spatial heterogeneity with Trichodesmium spp. appeared to be more abundant in the Bay of Bengal (p < 0.05), while Sagittula castanea (Alphaproteobacteria) was found to be more dominating in the equatorial region and offshores (p < 0.05). Non-metric multidimensional scaling analysis (NMDS) further confirmed distinct vertical and horizontal spatial variations in the EIO. Canonical correspondence analysis (CCA) indicated that temperature, salinity, and phosphate were the major environmental factors driving the distribution of the diazotroph communities. Overall, our study provides the first insight into the diversity and distribution of the diazotrophic communities in EIO. The findings from this study highlight distinct contributions of both non-cyanobacteria and cyanobacteria to N2 fixation. Moreover, our study reveals information that is critical for understanding spatial heterogeneity and distribution of diazotrophs, and their vital roles in nitrogen and carbon cycling.}, }
@article {pmid31037376, year = {2019}, author = {Robledo-Mahón, T and Silva-Castro, GA and Kuhar, U and Jamnikar-Ciglenečki, U and Barlič-Maganja, D and Aranda, E and Calvo, C}, title = {Effect of Composting Under Semipermeable Film on the Sewage Sludge Virome.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01365-z}, pmid = {31037376}, issn = {1432-184X}, abstract = {The addition of compost from sewage sludge to soils represents a sustainable option from an environmental and economic point of view, which involves the valorisation of these wastes. However, before their use as a soil amendment, compost has to reach the quality levels according to the normative, including microbial parameters. Viruses are not included in this regulation and they can produce agricultural problems and human diseases if the compost is not well sanitised. In this study, we carried out the analysis of the viral populations during a composting process with sewage sludge at an industrial scale, using semipermeable cover technology. Viral community was characterised by the presence of plant viruses and bacteriophages of enteric bacteria. The phytopathogen viruses were the group with the highest relative abundance in the sewage sludge sample and at 70 days of the composting process. The diversity of bacterial viruses and their specificity, with respect to the more abundant bacterial taxa throughout the process, highlights the importance of the interrelations between viral and bacterial communities in the control of pathogenic communities. These results suggest the possibility of using them as a tool to predict the effectiveness of the process.}, }
@article {pmid31031958, year = {2019}, author = {Collins, GE and Hogg, ID and Baxter, JR and Maggs-Kölling, G and Cowan, DA}, title = {Ancient landscapes of the Namib Desert harbor high levels of genetic variability and deeply divergent lineages for Collembola.}, journal = {Ecology and evolution}, volume = {9}, number = {8}, pages = {4969-4979}, doi = {10.1002/ece3.5103}, pmid = {31031958}, issn = {2045-7758}, abstract = {Aim: To assess spatial patterns of genetic and species-level diversity for Namib Desert Collembola using mitochondrial DNA cytochrome c oxidase subunit I (COI) gene sequences.<br><br>Location: Namib Desert gravel plains.<br><br>Taxon: Collembola (springtails).<br><br>Methods: A total of 77 soil samples were collected along NE-SW (60 km) and E-W (160 km) transects from within a 4,000 km2 area of the Namib Desert gravel plains. We extracted 434 springtails from the 37 samples which contained Collembola and sequenced them at the COI gene locus. In the absence of specific taxonomic keys and previous genetic data for these taxa, we used Generalized Mixed Yule Coalescent (GMYC) analyses to provide putative species-level designations.<br><br>Results: We obtained 341 successful COI sequences, 175 of which were unique haplotypes. GMYC analyses identified 30 putative species, with up to 28% sequence divergence (uncorrected p-distance). The distribution of genetic variants was disjunct, with 97% of haplotypes and 70% of &quot;GMYC species&quot; found only at single sites.<br><br>Main conclusions: Dispersal events, although rare, may be facilitated by environmental events such as prevailing onshore winds or occasional flow of rainwater to the coast. We conclude that the high genetic diversity we observed is the result of ancient springtail lineages, patchy distribution of suitable habitats, and limited dispersal (gene flow) among habitable locations.}, }
@article {pmid31031435, year = {2019}, author = {Gomes, J and Khandeparker, R and Meena, RM and Ramaiah, N}, title = {Bacterial Community Composition Markedly Altered by Coastal Hypoxia.}, journal = {Indian journal of microbiology}, volume = {59}, number = {2}, pages = {200-208}, doi = {10.1007/s12088-019-00790-5}, pmid = {31031435}, issn = {0046-8991}, abstract = {Monsoonal upwelling along south and central west coast of India leads to intense biological productivity. As a consequence of excess organic matter production following upwelling during June-October and low dissolved oxygen in the upwelled waters, denitrification occurs in the near shore waters. Implicitly, these processes ought to bring alterations in microbial communities. Therefore, diversity and community structure of bacteria from subsurface layers of a tropical region experiencing intense seasonal lows of oxygen were analyzed through sequencing of 16S rRNA gene clones. The overall diversity was more during hypoxic period of Fall intermonsoon (FIM, October) compared either to Spring intermonsoon (SIM, March) or summer monsoon (SuM, June) months. As many as 14 lineages of bacterial domains: Gammaproteobacteria (37%), Alphaproteobacteria (21%), Cyanobacteria (20%), Deltaproteobacteria (3%), Firmicutes (3%), Betaproteobacteria (2%), Acidobacteria (2%), Actinobacteria (7%), Marinimicrobia (2%), Bacteroidetes (1%), Verrucomicrobia (1%), Planctomycetes (0.4%), Chloroflexi (0.2%) and Omnitrophica bacterium (0.2%), were recognized from our coastal location. Notably, sequences of Planctomycetes, Chloroflexi and Omnitrophica bacterium were found exclusively during FIM. A generally higher representation of sequences of Betaproteobacteria during SuM and of Actinobacteria and Firmicutes during SIM was discernible. This study is thus useful to recognize that microbial community might undergo strong temporal shifts in the monsoon affected tropical coastal ecosystems.}, }
@article {pmid31031118, year = {2019}, author = {Enke, TN and Datta, MS and Schwartzman, J and Cermak, N and Schmitz, D and Barrere, J and Pascual-García, A and Cordero, OX}, title = {Modular Assembly of Polysaccharide-Degrading Marine Microbial Communities.}, journal = {Current biology : CB}, volume = {29}, number = {9}, pages = {1528-1535.e6}, doi = {10.1016/j.cub.2019.03.047}, pmid = {31031118}, issn = {1879-0445}, abstract = {Understanding the principles that govern the assembly of microbial communities across earth's biomes is a major challenge in modern microbial ecology. This pursuit is complicated by the difficulties of mapping functional roles and interactions onto communities with immense taxonomic diversity and of identifying the scale at which microbes interact [1]. To address this challenge, here, we focused on the bacterial communities that colonize and degrade particulate organic matter in the ocean [2-4]. We show that the assembly of these communities can be simplified as a linear combination of functional modules. Using synthetic polysaccharide particles immersed in natural bacterioplankton assemblages [1, 5], we showed that successional particle colonization dynamics are driven by the interaction of two types of modules: a first type made of narrowly specialized primary degraders, whose dynamics are controlled by particle polysaccharide composition, and a second type containing substrate-independent taxa whose dynamics are controlled by interspecific interactions-in particular, cross-feeding via organic acids, amino acids, and other metabolic byproducts. We show that, as a consequence of this trophic structure, communities can assemble modularly-i.e., by a simple sum of substrate-specific primary degrader modules, one for each complex polysaccharide in the particle, connected to a single broad-niche range consumer module. Consistent with this model, a linear combination of the communities on single-polysaccharide particles accurately predicts community composition on mixed-polysaccharide particles. Our results suggest that the assembly of heterotrophic communities that degrade complex organic materials follows simple design principles that could be exploited to engineer heterotrophic microbiomes.}, }
@article {pmid31031092, year = {2019}, author = {Hull, NM and Ling, F and Pinto, AJ and Albertsen, M and Jang, HG and Hong, PY and Konstantinidis, KT and LeChevallier, M and Colwell, RR and Liu, WT}, title = {Drinking Water Microbiome Project: Is it Time?.}, journal = {Trends in microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tim.2019.03.011}, pmid = {31031092}, issn = {1878-4380}, abstract = {Now is an opportune time to foster collaborations across sectors and geographical boundaries to enable development of best practices for drinking water (DW) microbiome research, focusing on accuracy and reproducibility of meta-omic techniques (while learning from past microbiome projects). A large-scale coordinated effort that builds on this foundation will enable the urgently needed comprehensive spatiotemporal understanding and control of DW microbiomes by engineering interventions to protect public health. This opinion paper highlights the need to initiate and conduct a large-scale coordinated DW microbiome project by addressing key knowledge gaps and recommends a roadmap for this effort.}, }
@article {pmid31030239, year = {2019}, author = {Omae, K and Fukuyama, Y and Yasuda, H and Mise, K and Yoshida, T and Sako, Y}, title = {Diversity and distribution of thermophilic hydrogenogenic carboxydotrophs revealed by microbial community analysis in sediments from multiple hydrothermal environments in Japan.}, journal = {Archives of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00203-019-01661-9}, pmid = {31030239}, issn = {1432-072X}, support = {16J11269//Grant-in-Aid from the Japan Society for the Promotion of Science (JSPS) Fellows/ ; 25252038//Japan Society for the Promotion of Science/ ; 16H06381//Japan Society for the Promotion of Science/ ; }, abstract = {In hydrothermal environments, carbon monoxide (CO) utilisation by thermophilic hydrogenogenic carboxydotrophs may play an important role in microbial ecology by reducing toxic levels of CO and providing H2 for fuelling microbial communities. We evaluated thermophilic hydrogenogenic carboxydotrophs by microbial community analysis. First, we analysed the correlation between carbon monoxide dehydrogenase (CODH)-energy-converting hydrogenase (ECH) gene cluster and taxonomic affiliation by surveying an increasing genomic database. We identified 71 genome-encoded CODH-ECH gene clusters, including 46 whose owners were not reported as hydrogenogenic carboxydotrophs. We identified 13 phylotypes showing > 98.7% identity with these taxa as potential hydrogenogenic carboxydotrophs in hot springs. Of these, Firmicutes phylotypes such as Parageobacillus, Carboxydocella, Caldanaerobacter, and Carboxydothermus were found in different environmental conditions and distinct microbial communities. The relative abundance of the potential thermophilic hydrogenogenic carboxydotrophs was low. Most of them did not show any symbiotic networks with other microbes, implying that their metabolic activities might be low.}, }
@article {pmid31026580, year = {2019}, author = {Han, M and Dsouza, M and Zhou, C and Li, H and Zhang, J and Chen, C and Yao, Q and Zhong, C and Zhou, H and Gilbert, JA and Wang, Z and Ning, K}, title = {Agricultural Risk Factors Influence Microbial Ecology in Honghu Lake.}, journal = {Genomics, proteomics &amp; bioinformatics}, volume = {17}, number = {1}, pages = {76-90}, doi = {10.1016/j.gpb.2018.04.008}, pmid = {31026580}, issn = {2210-3244}, abstract = {Agricultural activities, including stock-farming, planting industry, and fish aquaculture, can affect the physicochemical and biological characters of freshwater lakes. However, the effects of pollution producing by agricultural activities on microbial ecosystem of lakes remain unclear. Hence, in this work, we selected Honghu Lake as a typical lake that is influenced by agriculture activities. We collected water and sediment samples from 18 sites, which span a wide range of areas from impacted and less-impacted areas. We performed a geospatial analysis on the composition of microbial communities associated with physicochemical properties and antibiotic pollution of samples. The co-occurrence networks of water and sediment were also built and analyzed. Our results showed that the microbial communities of impacted and less-impacted samples of water were largely driven by the concentrations of TN, TP, NO3--N, and NO2--N, while those of sediment were affected by the concentrations of Sed-OM and Sed-TN. Antibiotics have also played important roles in shaping these microbial communities: the concentrations of oxytetracycline and tetracycline clearly reflected the variance in taxonomic diversity and predicted functional diversity between impacted and less-impacted sites in water and sediment samples, respectively. Furthermore, for samples from both water and sediment, large differences of network topology structures between impacted and less-impacted were also observed. Our results provide compelling evidence that the microbial community can be used as a sentinel of eutrophication and antibiotics pollution risk associated with agricultural activity; and that proper monitoring of this environment is vital to maintain a sustainable environment in Honghu Lake.}, }
@article {pmid31025063, year = {2019}, author = {Negi, A and Sarethy, IP}, title = {Microbial Biodeterioration of Cultural Heritage: Events, Colonization, and Analyses.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01366-y}, pmid = {31025063}, issn = {1432-184X}, abstract = {Geochemical cycles result in the chemical, physical, and mineralogical modification of rocks, eventually leading to formation of soil. However, when the stones and rocks are a part of historic buildings and monuments, the effects are deleterious. In addition, microorganisms also colonize these monuments over a period of time, resulting in formation of biofilms; their metabolites lead to physical weakening and discoloration of stone eventually. This process, known as biodeterioration, leads to a significant loss of cultural heritage. For formulating effective conservation strategies to prevent biodeterioration and restore monuments, it is important to know which microorganisms are colonizing the substrate and the different energy sources they consume to sustain themselves. With this view in scope, this review focuses on studies that have attempted to understand the process of biodeterioration, the mechanisms by which they colonize and affect the monuments, the techniques used for assessment of biodeterioration, and conservation strategies that aim to preserve the original integrity of the monuments. This review also includes the &quot;omics&quot; technologies that have started playing a large role in elucidating the nature of microorganisms, and how they can play a role in hastening the formulation of effective conservation strategies.}, }
@article {pmid31025062, year = {2019}, author = {Zhao, Z and Zhang, X and Cheng, M and Song, X and Zhang, Y and Zhong, X}, title = {Influences of Iron Compounds on Microbial Diversity and Improvements in Organic C, N, and P Removal Performances in Constructed Wetlands.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01379-7}, pmid = {31025062}, issn = {1432-184X}, support = {D-8005-18-0068-1/2//China Postdoctoral Science Foundation/ ; 51679041//National Natural Science Foundation of China/ ; A2-0203-00-100356//Shanghai Ocean University Ph. D Start-Up Fund/ ; 2017B020236002//program of. science and technology in Guangdong Province/ ; }, abstract = {The effects of various combinations of iron compounds on the contaminant removal performance in constructed wetlands (CWs) were explored under various initial iron concentrations, contaminant concentrations, different hydraulic retention time (HRT), and different temperatures. The Combo 6 (nanoscale zero-valent iron combined with Fe3+) in CW treatments showed the highest pollutant removal performance under the conditions of C2 initial iron dosage concentration (total iron 0.2 mM) and I2 initial contaminant concentration (COD:TN:TP = 60 mg/L:60 mg/L:1 mg/L) in influent after 72-h HRT. These results were directly verified by two different microbial tests (Biolog test and high-throughput pyrosequencing) and microbial community analysis (principal component analysis of community-level physiological profile, biodiversity index, cluster tree, relative abundance at order of taxonomy level). Specific bacteria related to significant improvements in contaminant removal were domesticated by various combinations of iron compounds. Iron dosage was advised as a green, new, and effective option for wastewater treatment. Graphical Abstract .}, }
@article {pmid31024771, year = {2019}, author = {Cipriano, MAP and Suleiman, AKA and da Silveira, APD and do Carmo, JB and Kuramae, EE}, title = {Bacterial community composition and diversity of two different forms of an organic residue of bioenergy crop.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6768}, doi = {10.7717/peerj.6768}, pmid = {31024771}, issn = {2167-8359}, abstract = {The use of residue of sugarcane ethanol industry named vinasse in fertirrigation is an established and widespread practice in Brazil. Both non-concentrated vinasse (NCV) and concentrated vinasse (CV) are used in fertirrigation, particularly to replace the potassium fertilizer. Although studies on the chemical and organic composition of vinasse and their impact on nitrous oxide emissions when applied in soil have been carried out, no studies have evaluated the microbial community composition and diversity in different forms of vinasse. We assessed the bacterial community composition of NCV and CV by non-culturable and culturable approaches. The non-culturable bacterial community was assessed by next generation sequencing of the 16S rRNA gene and culturable community by isolation of bacterial strains and molecular and biochemical characterization. Additionally, we assessed in the bacterial strains the presence of genes of nitrogen cycle nitrification and denitrification pathways. The microbial community based on 16S rRNA sequences of NCV was overrepresented by Bacilli and Negativicutes while CV was mainly represented by Bacilli class. The isolated strains from the two types of vinasse belong to class Bacilli, similar to Lysinibacillus, encode for nirK gene related to denitrification pathway. This study highlights the bacterial microbial composition particularly in CV what residue is currently recycled and recommended as a sustainable practice in sugarcane cultivation in the tropics.}, }
@article {pmid31024471, year = {2019}, author = {Lacerda-Júnior, GV and Noronha, MF and Cabral, L and Delforno, TP and de Sousa, STP and Fernandes-Júnior, PI and Melo, IS and Oliveira, VM}, title = {Land Use and Seasonal Effects on the Soil Microbiome of a Brazilian Dry Forest.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {648}, doi = {10.3389/fmicb.2019.00648}, pmid = {31024471}, issn = {1664-302X}, abstract = {Drylands occupy approximately 41% of the Earth's terrestrial surface. Climate change and land use practices are expected to affect biogeochemical cycling by the soil microbiome in these ecosystems. Understanding how soil microbial community might respond to these drivers is extremely important to mitigate the processes of land degradation and desertification. The Caatinga, an exclusively Brazilian biome composed of an extensive seasonal tropical dry forest, is exposed to variable spatiotemporal rainfall patterns as well as strong human-driven pressures. Herein, an integrated analysis of shotgun metagenomics approach coupled to meteorological data was employed to unravel the impact of seasonality and land use change on soil microbiome from preserved and agriculture-affected experimental fields in Caatinga drylands. Multivariate analysis suggested that microbial communities of preserved soils under seasonal changes were shaped primarily by water deficit, with a strong increase of Actinobacteria and Proteobacteria members in the dry and rainy seasons, respectively. In contrast, nutrient availability notably played a critical role in driving the microbial community in agriculture-affected soils. The strong enrichment of bacterial genera belonging to the poorly-known phylum Acidobacteria ('Candidatus Solibacter' and 'Candidatus Koribacter') in soils from dry season affected by ferti-irrigation practices presupposes a contrasting copiotrophic lifestyle and ecological role in mitigating the impact of chemical fertilization. Functional analyses identify overrepresented genes related to osmotic stress response (synthesis of osmoprotectant compounds, accumulation of potassium ions) and preferential carbon and nitrogen utilization when comparing the microbiome of preserved soils under seasonal changes, reflecting differences in the genetic potential for nutrient cycling and C acquisition in the environment. However, the prevalence of nitrosative stress and denitrification functions in irrigation/fertilization-affected soils of the dry season clearly suggest that nutrient input and disruption of natural water regime may impact biogeochemical cycles linked to the microbial processes, with potential impacts on the ecosystem functionality. These findings help to better understand how natural seasonality and agricultural management differentially affect soil microbial ecology from dry forests, providing support for the development of more sustainable land management in dryland ecosystems.}, }
@article {pmid31021624, year = {2019}, author = {Mani, T and Primpke, S and Lorenz, C and Gerdts, G and Burkhardt-Holm, P}, title = {Microplastic Pollution in Benthic Midstream Sediments of the Rhine River.}, journal = {Environmental science &amp; technology}, volume = {53}, number = {10}, pages = {6053-6062}, doi = {10.1021/acs.est.9b01363}, pmid = {31021624}, issn = {1520-5851}, abstract = {Rivers are major transport vectors for microplastics (MP) toward the sea. However, there is evidence that MP can temporarily or permanently be inhibited from migrating downstream by retention in sediments or ingestion by organisms. MP concentrations, compositions, and fate within the different compartments of the fluvial environment are poorly understood. Here, benthic, midstream sediments of two undammed, open-flowing stretches were investigated in the Rhine River, one of the world's busiest inland waterways. Twenty-five samples were collected at ten sites via riverbed access through a diving bell or dredging. We performed the first comprehensive analysis of riverbed sediment aliquots that avoids visual selection bias using state-of-the art automated micro-Fourier-transform infrared spectroscopy (μFTIR) imaging. MP numbers ranged between 0.26 ± 0.01 and 11.07 ± 0.6 × 103 MP kg-1 while MP particles <75 μm accounted for a mean numerical proportion ± SD of 96 ± 6%. MP concentrations decreased with sediment depth. Eighteen polymers were identified in the size range of 11-500 μm; the acrylates/polyurethane/varnish (APV) cluster was found at all sites (mean numerical proportion, 70 ± 19%), possibly indicating particulate pollution from ship antifouling paint. Overall, polymers denser than freshwater (>1 g cm-3) dominated (85 ± 18%), which contrasts the large proportions of low-density polymers previously reported in near-surface compartments of the Rhine.}, }
@article {pmid31019271, year = {2019}, author = {Averill, C and Cates, LL and Dietze, MC and Bhatnagar, JM}, title = {Spatial vs. temporal controls over soil fungal community similarity at continental and global scales.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0420-1}, pmid = {31019271}, issn = {1751-7370}, support = {1638577//National Science Foundation (NSF)/ ; Boston University BRITE Research Experiences for Undergraduates Program//National Science Foundation (NSF)/ ; 1638577//National Science Foundation (NSF)/ ; 1638577//National Science Foundation (NSF)/ ; Climate and Global Change Postdoctoral Fellowship//United States Department of Commerce | National Oceanic and Atmospheric Administration (NOAA)/ ; }, abstract = {Large-scale environmental sequencing efforts have transformed our understanding of the spatial controls over soil microbial community composition and turnover. Yet, our knowledge of temporal controls is comparatively limited. This is a major uncertainty in microbial ecology, as there is increasing evidence that microbial community composition is important for predicting microbial community function in the future. Here, we use continental- and global-scale soil fungal community surveys, focused within northern temperate latitudes, to estimate the relative contribution of time and space to soil fungal community turnover. We detected large intra-annual temporal differences in soil fungal community similarity, where fungal communities differed most among seasons, equivalent to the community turnover observed over thousands of kilometers in space. inter-annual community turnover was comparatively smaller than intra-annual turnover. Certain environmental covariates, particularly climate covariates, explained some spatial-temporal effects, though it is unlikely the same mechanisms drive spatial vs. temporal turnover. However, these commonly measured environmental covariates could not fully explain relationships between space, time and community composition. These baseline estimates of fungal community turnover in time provide a starting point to estimate the potential duration of legacies in microbial community composition and function.}, }
@article {pmid31016338, year = {2019}, author = {Nappi, J and Soldi, E and Egan, S}, title = {Diversity and Distribution of Bacteria Producing Known Secondary Metabolites.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01380-0}, pmid = {31016338}, issn = {1432-184X}, support = {FT130100828//Australian Research Council/ ; }, abstract = {There is an increasing interest in the utilisation of marine bioactive compounds as novel biopharmaceuticals and agrichemicals; however, little is known about the environmental distribution for many of these molecules. Here, we aimed to elucidate the environmental distribution and to detect the biosynthetic gene clusters in environmental samples of four bioactive compounds, namely violacein, tropodithietic acid (TDA), tambjamine and the antibacterial protein AlpP. Our database analyses revealed high bacterial diversity for AlpP and violacein producers, while TDA-producing bacteria were mostly associated with marine surfaces and all belonged to the roseobacter group. In contrast, the tambjamine cluster was only found in the genomes of two Pseudoalteromonas species and in one terrestrial species belonging to the Cupriavidus genus. Using a PCR-based screen of different marine samples, we detected TDA and violacein genes associated with the microbiome of Ulva and Protohyale niger and tambjamine genes associated with Nodilittorina unifasciata; however, alpP was not detected. These results highlight the variable distribution of the genes encoding these four bioactive compounds, including their detection from the surface of multiple marine eukaryotic hosts. Determining the natural distribution of these gene clusters will help to understand the ecological importance of these metabolites and the bacteria that produce them.}, }
@article {pmid31015413, year = {2019}, author = {Kits, KD and Jung, MY and Vierheilig, J and Pjevac, P and Sedlacek, CJ and Liu, S and Herbold, C and Stein, LY and Richter, A and Wissel, H and Brüggemann, N and Wagner, M and Daims, H}, title = {Low yield and abiotic origin of N2O formed by the complete nitrifier Nitrospira inopinata.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {1836}, doi = {10.1038/s41467-019-09790-x}, pmid = {31015413}, issn = {2041-1723}, abstract = {Nitrous oxide (N2O) and nitric oxide (NO) are atmospheric trace gases that contribute to climate change and affect stratospheric and ground-level ozone concentrations. Ammonia oxidizing bacteria (AOB) and archaea (AOA) are key players in the nitrogen cycle and major producers of N2O and NO globally. However, nothing is known about N2O and NO production by the recently discovered and widely distributed complete ammonia oxidizers (comammox). Here, we show that the comammox bacterium Nitrospira inopinata is sensitive to inhibition by an NO scavenger, cannot denitrify to N2O, and emits N2O at levels that are comparable to AOA but much lower than AOB. Furthermore, we demonstrate that N2O formed by N. inopinata formed under varying oxygen regimes originates from abiotic conversion of hydroxylamine. Our findings indicate that comammox microbes may produce less N2O during nitrification than AOB.}, }
@article {pmid31015324, year = {2019}, author = {Easton, AV and Quiñones, M and Vujkovic-Cvijin, I and Oliveira, RG and Kepha, S and Odiere, MR and Anderson, RM and Belkaid, Y and Nutman, TB}, title = {The Impact of Anthelmintic Treatment on Human Gut Microbiota Based on Cross-Sectional and Pre- and Postdeworming Comparisons in Western Kenya.}, journal = {mBio}, volume = {10}, number = {2}, pages = {}, doi = {10.1128/mBio.00519-19}, pmid = {31015324}, issn = {2150-7511}, abstract = {Murine studies suggest that the presence of some species of intestinal helminths is associated with changes in host microbiota composition and diversity. However, studies in humans have produced varied conclusions, and the impact appears to vary widely depending on the helminth species present. To demonstrate how molecular approaches to the human gut microbiome can provide insights into the complex interplay among disparate organisms, DNA was extracted from cryopreserved stools collected from residents of 5 rural Kenyan villages prior to and 3 weeks and 3 months following albendazole (ALB) therapy. Samples were analyzed by quantitative PCR (qPCR) for the presence of 8 species of intestinal parasites and by MiSeq 16S rRNA gene sequencing. Based on pretreatment results, the presence of neither Ascaris lumbricoides nor Necator americanus infection significantly altered the overall diversity of the microbiota in comparison with age-matched controls. Following ALB therapy and clearance of soil-transmitted helminths (STH), there were significant increases in the proportion of the microbiota made up by Clostridiales (P = 0.0002; average fold change, 0.57) and reductions in the proportion made up by Enterobacteriales (P = 0.0004; average fold change, -0.58). There was a significant posttreatment decrease in Chao1 richness, even among individuals who were uninfected pretreatment, suggesting that antimicrobial effects must be considered in any posttreatment setting. Nevertheless, the helminth-associated changes in Clostridiales and Enterobacteriales suggest that clearance of STH, and of N. americanus in particular, alters the gut microbiota.IMPORTANCE The gut microbiome is an important factor in human health. It is affected by what we eat, what medicines we take, and what infections we acquire. In turn, it affects the way we absorb nutrients and whether we have excessive intestinal inflammation. Intestinal worms may have an important impact on the composition of the gut microbiome. Without a complete understanding of the impact of mass deworming programs on the microbiome, it is impossible to accurately calculate the cost-effectiveness of such public health interventions and to guard against any possible deleterious side effects. Our research examines this question in a &quot;real-world&quot; setting, using a longitudinal cohort, in which individuals with and without worm infections are treated with deworming medication and followed up at both three weeks and three months posttreatment. We quantify the impact of roundworms and hookworms on gut microbial composition, suggesting that the impact is small, but that treatment of hookworm infection results in significant changes. This work points to the need for follow-up studies to further examine the impact of hookworm on the gut microbiota and determine the health consequences of the observed changes.}, }
@article {pmid31015144, year = {2019}, author = {Corno, G and Yang, Y and Eckert, EM and Fontaneto, D and Fiorentino, A and Galafassi, S and Zhang, T and Di Cesare, A}, title = {Effluents of wastewater treatment plants promote the rapid stabilization of the antibiotic resistome in receiving freshwater bodies.}, journal = {Water research}, volume = {158}, number = {}, pages = {72-81}, doi = {10.1016/j.watres.2019.04.031}, pmid = {31015144}, issn = {1879-2448}, abstract = {Treated wastewater discharged into the environment acts as a disturbance of the natural microbial communities in terms of taxonomic composition and of functional gene pool, including antibiotic resistance genes. We tested whether stochastic and heterogeneous site-specific trajectories or generalities, potentially driven by deterministic processes, control the fate of allochthonous bacteria from anthropogenic sources and the persistence of their functional traits in freshwater. Finding generalities would allow the identification of wastewater treatments that could be effective in abating determinants of antibiotic resistance. We analysed the short-term response of native bacterial communities in waters exposed to the disturbance of wastewater at different dilutions, using a metagenomic approach that revealed both microbial community composition and the scope and abundance of the resistome that can pose indirect risks to human health. We found that the taxonomic composition of the communities after the disturbance was driven by case-specific stochastic processes, whereas the resistome had a deterministic trajectory, rapidly stabilising its functional traits with higher proportions of wastewater effluents, regardless of differences in taxonomic composition, richness of antibiotic resistance genes and of bacterial taxa, phenotypic features of the bacterial communities, and type of wastewater treatment. The observed deterministic proliferation of resistomes in freshwater bodies receiving wastewater effluents, suggests that this process may contribute to the global propagation of antibiotic resistance, and thus calls for new legislations promoting alternative tertiary treatments for the wastewater reuse, and targeting bacterial functional traits and not only bacterial abundances.}, }
@article {pmid31009873, year = {2019}, author = {Lin, S and Wang, TY and Xu, HR and Zhang, XN and Wang, Q and Liu, R and Li, Q and Bi, KS}, title = {A systemic combined nontargeted and targeted LC-MS based metabolomic strategy of plasma and liver on pathology exploration of alpha-naphthylisothiocyanate induced cholestatic liver injury in mice.}, journal = {Journal of pharmaceutical and biomedical analysis}, volume = {171}, number = {}, pages = {180-192}, doi = {10.1016/j.jpba.2019.04.009}, pmid = {31009873}, issn = {1873-264X}, abstract = {The pathology of cholestatic liver injury (CLI) was complicated, which has limited the development of anti-cholestatic drugs for a long period. Metabolomic researches focused on global and dynamic changes of the organism could shed some light on mechanism investigation. In order to characterize and validate metabolite alterations of alpha-naphthylisothiocyanate (ANIT) induced CLI in C57BL/6 mice, a systemic metabolomic approach combining nontargeted HPLC-ESI-QTOF-MS and targeted UFLC-ESI-MS/MS technologies were developed innovatively. Multivariate data analysis was applied to determine the changes of metabolites in processed plasma and liver samples between control and model groups. Afterwards, 38 potential plasma biomarkers and 17 potential liver biomarkers involved in bile acid (BA) biosynthesis, phospholipid biosynthesis, sphingolipid metabolism, alpha linolenic acid and linoleic acid metabolism, as well as arachidonic acid metabolism were found and attributed as potential biomarkers and influential pathways of cholestasis. Based on correlation analysis, BA biosynthesis played the most important role in ANIT induced CLI, thereinto, major BAs were carried out with quantitative analysis. Targeted metabolomic results showed that the increase of BAs might have an impact on intestinal microbial ecology which could aggravate liver injury probably, among which cholic acid (CA) and taurocholic acid (TCA) were the most sensitive indicators of ANIT induced CLI in both plasma and liver. In conclusion, CLI might correlate significantly with hepatocyte necrosis, metabolic disorders and imbalance of intestinal microbiome ecology triggered by BA accumulation.}, }
@article {pmid31005840, year = {2019}, author = {Qian, X and Gu, J and Sun, W and Wang, X and Li, H}, title = {Effects of passivators on antibiotic resistance genes and related mechanisms during composting of copper-enriched pig manure.}, journal = {The Science of the total environment}, volume = {674}, number = {}, pages = {383-391}, doi = {10.1016/j.scitotenv.2019.04.197}, pmid = {31005840}, issn = {1879-1026}, mesh = {Animals ; Charcoal/chemistry ; Composting/*methods ; Drug Resistance, Microbial/*genetics ; *Genes, Bacterial ; Manure/microbiology ; Zeolites/chemistry ; }, abstract = {Due to the intensive use of feed additives in livestock farming, animal manure has become a hotspot for antibiotics, heavy metals, and antibiotic resistance genes (ARGs). Unlike antibiotics, heavy metals cannot be degraded during composting and thus could pose a persistent co-selective pressure in the proliferation of antibiotic resistance. Passivators are commonly applied to immobilize metals and improve the safety of compost. However, little is known about the effects of various passivators on ARGs and mobile genetic elements (MGEs) during composting and the underlying mechanisms involved. Thus, three typical passivators (biochar, fly ash, and zeolite) were applied during the composting of copper-enriched pig manure, and their effects on ARGs, copper resistance genes, MGEs, and the bacterial communities were examined. Compared to the control, all passivator treatments reduced the abundances of at least six ARGs (tetC, tetG, tetQ, tetX, sul1, and ermB) by 0.23-1.09 logs and of two MGEs (intI1 and ISCR1) by 26-85% after composting. Biochar and fly ash also significantly reduced the abundances of intI2 and Tn914/1545. In contrast, abundances of copper resistance genes were not reduced by passivators, implying that the decreased co-selective pressure may not be a major contributor to ARG reductions in this study. Procrustes analysis and redundancy analysis demonstrated that shifts in the bacterial community determined the changes in the abundances of ARGs, and the variation in MGEs and DTPA-Cu can also partially explain the ARG variance. Overall, all of three passivators can be used to reduce the health risks associated with ARGs in livestock manure, and biochar performed the best at reducing ARGs and MGEs.}, }
@article {pmid31001657, year = {2019}, author = {Mastan, A and Bharadwaj, R and Kushwaha, RK and Vivek Babu, CS}, title = {Functional Fungal Endophytes in Coleus forskohlii Regulate Labdane Diterpene Biosynthesis for Elevated Forskolin Accumulation in Roots.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01376-w}, pmid = {31001657}, issn = {1432-184X}, abstract = {Coleus forskohlii is a perennial medicinal shrub cultivated mainly for its forskolin content. The plant has been used since ancient times in ayurvedic traditional medicines for the treatment of hypertension, glaucoma, asthma, congestive heart failures, obesity, and cancer. Use of endophytic microorganisms presents a special interest for the development of value-added bioactive compounds through agriculture. Limited investigations have been undertaken on in planta enhancement of forskolin content using endophytic fungus in sustainable agriculture. Here we report specific roles of three fungal endophytes, Fusarium redolens (RF1), Phialemoniopsis cornearis (SF1), and Macrophomina pseudophaseolina (SF2), functionally acting as plant probiotic fungus, regulating secondary metabolite (forskolin) biosynthesis in C. forskohlii. The root endophyte, RF1, and shoot endophytes, SF1 and SF2, were found to enhance forskolin content by 52 to 88% in pot and 60 to 84% in field experiments as compared to uninoculated control plants. The three endophytes also enhanced total biomass owing to plant growth promoting properties. The expression of diterpene synthases (CfTPSs) like CfTPS1, CfTPS2, CfTPS3, and CfTPS4 were significantly upregulated in endophyte-treated C. forskohlii plants. Elevated expression of key diterpene synthases (CfTPS2) in the forskolin biosynthesis pathway, exclusively present in the root cork of C. forskohlii, was observed following SF2 endophyte treatment. Furthermore, endophyte treatments conferred a variety of antagonistic activity against nematode galls (80%) and plant pathogens like Fusarium oxysporum, Colletotricum gloeosporioides, and Sclerotium rolfsii. RF1 and SF1 fungal endophytes showed positive for IAA production; however, SF1 also indicated phosphate solubilization activity. Overall, the qualitative and quantitative improvement of in planta forskolin enhancement represents an area of high commercial interest, and hence, our work focused on novel insights for the application of three fungal endophytes for in planta enhancement of forskolin content for C. forskohlii cultivation by a sustainable approach.}, }
@article {pmid31000488, year = {2019}, author = {Ladau, J and Eloe-Fadrosh, EA}, title = {Spatial, Temporal, and Phylogenetic Scales of Microbial Ecology.}, journal = {Trends in microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tim.2019.03.003}, pmid = {31000488}, issn = {1878-4380}, abstract = {Microbial communities play a major role in disease, biogeochemical cycling, agriculture, and bioremediation. However, identifying the ecological processes that govern microbial community assembly and disentangling the relative impacts of those processes has proven challenging. Here, we propose that this discord is due to microbial systems being studied at different spatial, temporal, and phylogenetic scales. We argue that different processes dominate at different scales, and that through a more explicit consideration of spatial, temporal, and phylogenetic grains and extents (the two components of scale) a more accurate, clear, and useful understanding of microbial community assembly can be developed. We demonstrate the value of applying ecological concepts of scale to microbiology, specifically examining their application to nestedness, legacy effects, and taxa-area relationships of microbial systems. These proposed considerations of scale will help resolve long-standing debates in microbial ecology regarding the processes determining the assembly of microbial communities, and provide organizing principles around which hypotheses and theories can be developed.}, }
@article {pmid30993370, year = {2019}, author = {Li, W and Wang, M and Burgaud, G and Yu, H and Cai, L}, title = {Fungal Community Composition and Potential Depth-Related Driving Factors Impacting Distribution Pattern and Trophic Modes from Epi- to Abyssopelagic Zones of the Western Pacific Ocean.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01374-y}, pmid = {30993370}, issn = {1432-184X}, abstract = {Fungi play an important role in cycling organic matter and nutrients in marine ecosystems. However, the distribution of fungal communities in the ocean, especially the vertical distribution along depth in the water column, remained poorly understood. Here, we assess the depth-related distribution pattern of fungal communities along the water column from epi- to abyssopelagic zones of the Western Pacific Ocean using internal transcribed spacer 2 (ITS2) metabarcoding. Majority of the assigned OTUs were affiliated to Ascomycota, followed by three other minor phyla (Basidiomycota, Chytridiomycota, and Mucoromycota). The epipelagic zone harbored a higher OTU richness with distinct fungal communities as compared with meso-, bathy-, and abyssopelagic zones. Across the whole water column, depth appears as a key parameter for both fungal α- and β-diversity. However, when the dataset was split into the upper (5-500 m) and deeper (below 500 m) layers, no significant correlation was observed between depth and community compositions. In the upper layer, temperature and dissolved oxygen were recognized as the primary environmental factors shaping fungal α- and β- diversity. By parsing fungal OTUs into ecological categories, multi-trophic mode of nutrition was found to be more prevalent with increasing depth, suggesting a potential adaptation to the extreme conditions of the deep sea. This study provides new and meaningful information on the depth-stratified fungal diversity, community structure, and putative ecological roles in the open sea.}, }
@article {pmid30992445, year = {2019}, author = {Lax, S and Cardona, C and Zhao, D and Winton, VJ and Goodney, G and Gao, P and Gottel, N and Hartmann, EM and Henry, C and Thomas, PM and Kelley, ST and Stephens, B and Gilbert, JA}, title = {Microbial and metabolic succession on common building materials under high humidity conditions.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {1767}, doi = {10.1038/s41467-019-09764-z}, pmid = {30992445}, issn = {2041-1723}, support = {T32 EB009412/EB/NIBIB NIH HHS/United States ; }, mesh = {Bacteria/genetics/isolation &amp; purification/*metabolism ; Construction Materials/*microbiology ; Environmental Monitoring/*methods ; Fungi/genetics/isolation &amp; purification/*metabolism ; Humidity ; Phylogeny ; RNA, Ribosomal, 16S/isolation &amp; purification ; Viruses/genetics/isolation &amp; purification/*metabolism ; }, abstract = {Despite considerable efforts to characterize the microbial ecology of the built environment, the metabolic mechanisms underpinning microbial colonization and successional dynamics remain unclear, particularly at high moisture conditions. Here, we applied bacterial/viral particle counting, qPCR, amplicon sequencing of the genes encoding 16S and ITS rRNA, and metabolomics to longitudinally characterize the ecological dynamics of four common building materials maintained at high humidity. We varied the natural inoculum provided to each material and wet half of the samples to simulate a potable water leak. Wetted materials had higher growth rates and lower alpha diversity compared to non-wetted materials, and wetting described the majority of the variance in bacterial, fungal, and metabolite structure. Inoculation location was weakly associated with bacterial and fungal beta diversity. Material type influenced bacterial and viral particle abundance and bacterial and metabolic (but not fungal) diversity. Metabolites indicative of microbial activity were identified, and they too differed by material.}, }
@article {pmid30989355, year = {2019}, author = {Nilsson, LKJ and de Oliveira, MR and Marinotti, O and Rocha, EM and Håkansson, S and Tadei, WP and de Souza, AQL and Terenius, O}, title = {Characterization of Bacterial Communities in Breeding Waters of Anopheles darlingi in Manaus in the Amazon Basin Malaria-Endemic Area.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01369-9}, pmid = {30989355}, issn = {1432-184X}, support = {348-2012-622//Vetenskapsrådet/ ; }, abstract = {The microbiota in mosquito breeding waters can affect ovipositing mosquitoes, have effects on larval development, and can modify adult mosquito-gut bacterial composition. This, in turn, can affect transmission of human pathogens such as malaria parasites. Here, we explore the microbiota of four breeding sites for Anopheles darlingi, the most important malaria vector in Latin America. The sites are located in Manaus in the Amazon basin in Brazil, an area of active malaria transmission. Using 16S rRNA gene sequencing by MiSeq, we found that all sites were dominated by Proteobacteria and Firmicutes and that 94% of the total number of reads belonged to 36 operational taxonomic units (OTUs) identified in all sites. Of these, the most common OTUs belonged to Escherichia/Shigella, Staphylococcus, and Pseudomonas. Of the remaining 6% of the reads, the OTUs found to differentiate between the four sites belonged to the orders Burkholderiales, Actinomycetales, and Clostridiales. We conclude that An. darlingi can develop in breeding waters with different surface-water bacteria, but that the common microbiota found in all breeding sites might indicate or contribute to a suitable habitat for this important malaria vector.}, }
@article {pmid30989354, year = {2019}, author = {Newsham, KK and Tripathi, BM and Dong, K and Yamamoto, N and Adams, JM and Hopkins, DW}, title = {Bacterial Community Composition and Diversity Respond to Nutrient Amendment but Not Warming in a Maritime Antarctic Soil.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01373-z}, pmid = {30989354}, issn = {1432-184X}, support = {NE/D00893X/1//Natural Environment Research Council/ ; 2018R1C1B6007755//National Research Foundation of Korea/ ; }, abstract = {A resumption of climate warming in maritime Antarctica, arising from continued greenhouse gas emissions to the atmosphere, is predicted to lead to further expansions of plant populations across the region, with consequent increases in nutrient inputs to soils. Here, we test the main and interactive effects of warming, applied with open top chambers (OTCs), and nutrient amendment with tryptic soy broth (TSB), an artificial growth substrate, on bacterial community composition and diversity using Illumina sequencing of 16S rRNA genes in soil from a field experiment in the southern maritime Antarctic. Substantial effects of TSB application on bacterial communities were identified after 49 months, including reduced diversity, altered phylogenetic community assembly processes, increased Proteobacteria-to-Acidobacteria ratios and significant divergence in community composition, notably increases in the relative abundances of the gram-positive genera Arthrobacter, Paeniglutamicibacter and Planococcus. Contrary to previous observations from other maritime Antarctic field warming experiments, we recorded no effects of warming with OTCs, or interactive effects of OTCs and TSB application, on bacterial community composition or diversity. Based on these findings, we conclude that further warming of the maritime Antarctic is unlikely to influence soil bacterial community composition or diversity directly, but that increased nutrient inputs arising from enhanced plant growth across the region may affect the composition of soil bacterial communities, with possible effects on ecosystem productivity.}, }
@article {pmid30988401, year = {2019}, author = {Tanaka, SE and Dayi, M and Maeda, Y and Tsai, IJ and Tanaka, R and Bligh, M and Takeuchi-Kaneko, Y and Fukuda, K and Kanzaki, N and Kikuchi, T}, title = {Stage-specific transcriptome of Bursaphelenchus xylophilus reveals temporal regulation of effector genes and roles of the dauer-like stages in the lifecycle.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6080}, doi = {10.1038/s41598-019-42570-7}, pmid = {30988401}, issn = {2045-2322}, support = {15H04514&amp;#x2019;//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 26292178//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 16H04722//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 15H04521//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; }, abstract = {The pine wood nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease, one of the most devastating forest diseases in East Asian and West European countries. The lifecycle of B. xylophilus includes four propagative larval stages and gonochoristic adults which are involved in the pathogenicity, and two stages of dispersal larvae involved in the spread of the disease. To elucidate the ecological roles of each developmental stage in the pathogenic life cycle, we performed a comprehensive transcriptome analysis using RNA-seq generated from all developmental stages of B. xylophilus and compared transcriptomes between stages. We found more than 9000 genes are differentially expressed in at least one stage of the life cycle including genes involved in general nematode biology such as reproduction and moulting but also effector genes likely to be involved in parasitism. The dispersal-stage transcriptome revealed its analogy to C. elegans dauer and the distinct roles of the two larval stages from each other regarding survival and transmission. This study provides important insights and resources to understand B. xylophilus parasitic biology.}, }
@article {pmid30980672, year = {2019}, author = {Pratama, AA and van Elsas, JD}, title = {Gene mobility in microbiomes of the mycosphere and mycorrhizosphere -role of plasmids and bacteriophages.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {5}, pages = {}, doi = {10.1093/femsec/fiz053}, pmid = {30980672}, issn = {1574-6941}, abstract = {Microbial activity in soil, including horizontal gene transfer (HGT), occurs in soil hot spots and at &quot;hot moments&quot;. Given their capacities to explore soil for nutrients, soil fungi (associated or not with plant roots) can act as (1) selectors of myco(rrhizo)sphere-adapted organisms and (2) accelerators of HGT processes across the cell populations that are locally present. This minireview critically examines our current understanding of the drivers of gene mobility in the myco(rrhizo)sphere. We place a special focus on the role of two major groups of gene mobility agents, i.e. plasmids and bacteriophages. With respect to plasmids, there is mounting evidence that broad-host-range (IncP-1β and PromA group) plasmids are prominent drivers of gene mobility across mycosphere inhabitants. A role of IncP-1β plasmids in Fe uptake processes has been revealed. Moreover, a screening of typical mycosphere-inhabiting Paraburkholderia spp. revealed carriage of integrated plasmids, next to prophages, that presumably confer fitness enhancements. In particular, functions involved in biofilm formation and nutrient uptake were thus identified. The potential of the respective gene mobility agents to promote the movement of such genes is critically examined.}, }
@article {pmid30980101, year = {2019}, author = {Ogwu, MC and Srinivasan, S and Dong, K and Ramasamy, D and Waldman, B and Adams, JM}, title = {Community Ecology of Deinococcus in Irradiated Soil.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01343-5}, pmid = {30980101}, issn = {1432-184X}, support = {2016E1D1A1B03930385//National Research Foundation Korea/ ; 2017R1D1A1B03035583//National Foundation foundation Korea/ ; }, abstract = {Deinococcus is a genus of soil bacteria known for radiation resistance. However, the effects of radiation exposure on its community structure are unknown. We exposed soil to three levels of gamma radiation, 0.1 kGy/h (low), 1 kGy/h (medium), and 3 kGy/h (high), once a week for 6 weeks and then extracted soil DNA for 16S rRNA amplicon sequencing. We found the following: (1) Increasing radiation dose produced a major increase in relative abundance of Deinococcus, reaching ~ 80% of reads at the highest doses. Differing abundances of the various Deinococcus species in relation to exposure levels indicate distinct &quot;radiation niches.&quot; At 3 kGy/h, a single OTU identified as D. ficus overwhelmingly dominated the mesocosms. (2) Corresponding published genome data show that the dominant species at 3 kGy/h, D. ficus, has a larger and more complex genome than other Deinococcus species with a greater proportion of genes related to DNA and nucleotide metabolism, cell wall, membrane, and envelope biogenesis as well as more cell cycle control, cell division, and chromosome partitioning-related genes. Deinococcus ficus also has a higher guanine-cytosine ratio than most other Deinococcus. These features may be linked to genome stability and may explain its greater abundance in this apparently competitive system, under high-radiation exposures. (3) Genomic analysis suggests that Deinococcus, including D. ficus, are capable of utilizing diverse carbon sources derived from both microbial cells killed by the radiation (including C5-C12-containing compounds, like arabinose, lactose, N-acetyl-D-glucosamine) and plant-derived organic matter in the soil (e.g., cellulose and hemicellulose). (4) Overall, based on its metagenome, even the most highly irradiated (3 kGy/h) soil possesses a wide range of the activities necessary for a functional soil system. Future studies may consider the resilience and sustainability of such soils in a high-radiation environment.}, }
@article {pmid30980037, year = {2019}, author = {Lee, KS and Palatinszky, M and Pereira, FC and Nguyen, J and Fernandez, VI and Mueller, AJ and Menolascina, F and Daims, H and Berry, D and Wagner, M and Stocker, R}, title = {Publisher Correction: An automated Raman-based platform for the sorting of live cells by functional properties.}, journal = {Nature microbiology}, volume = {4}, number = {5}, pages = {902-903}, doi = {10.1038/s41564-019-0446-1}, pmid = {30980037}, issn = {2058-5276}, abstract = {An amendment to this paper has been published and can be accessed via a link at the top of the paper.}, }
@article {pmid30977724, year = {2019}, author = {Gralka, M and Hallatschek, O}, title = {Environmental heterogeneity can tip the population genetics of range expansions.}, journal = {eLife}, volume = {8}, number = {}, pages = {}, doi = {10.7554/eLife.44359}, pmid = {30977724}, issn = {2050-084X}, support = {R01 GM115851/GM/NIGMS NIH HHS/United States ; }, abstract = {The population genetics of most range expansions is thought to be shaped by the competition between Darwinian selection and random genetic drift at the range margins. Here, we show that the evolutionary dynamics during range expansions is highly sensitive to additional fluctuations induced by environmental heterogeneities. Tracking mutant clones with a tunable fitness effect in bacterial colonies grown on randomly patterned surfaces we found that environmental heterogeneity can dramatically reduce the efficacy of selection. Time-lapse microscopy and computer simulations suggest that this effect arises generically from a local 'pinning' of the expansion front, whereby stretches of the front are slowed down on a length scale that depends on the structure of the environmental heterogeneity. This pinning focuses the range expansion into a small number of 'lucky' individuals with access to expansion paths, altering the neutral evolutionary dynamics and increasing the importance of chance relative to selection.}, }
@article {pmid30976843, year = {2019}, author = {Salerno, C and Berardi, G and Laera, G and Pollice, A}, title = {Functional Response of MBR Microbial Consortia to Substrate Stress as Revealed by Metaproteomics.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01360-4}, pmid = {30976843}, issn = {1432-184X}, abstract = {Bacterial consortia have a primary role in the biological degradations occurring in activated sludge for wastewater treatment, for their capacities to metabolize the polluting matter. Therefore, the knowledge of the main metabolic pathways for the degradation of pollutants becomes critical for a correct design and operation of wastewater treatment plants. The metabolic activity of the different bacterial groups in activated sludge is commonly investigated through respirometry. Furthermore, in the last years, the development of &quot;omic&quot; approaches has offered more opportunities to integrate or substitute the conventional microbiological assays and to deeply understand the taxonomy and dynamics of complex microbial consortia. In the present work, an experimental membrane bioreactor (MBR) was set up and operated for the treatment of municipal wastewater, and the effects of a sudden decrease of the organic supply on the activated sludge were investigated. Both respirometric and metaproteomic approaches revealed a resistance of autotrophic bacteria to the substrate stress, and particularly of nitrifying bacteria. Furthermore, metaproteomics allowed the identification of the taxonomy of the microbial consortium based on its protein expression, unveiling the prevalence of Sorangium and Nitrosomonas genera both before and after the organic load decrease. Moreover, it confirmed the results obtained through respirometry and revealed a general expression of proteins involved in metabolism and transport of nitrogen, or belonging to nitrifying species like Nitrosomonas europeae, Nitrosomonas sp. AL212, or Nitrospira defluvii.}, }
@article {pmid30976842, year = {2019}, author = {Vieira, LC and da Silva, DKA and de Melo, MAC and Escobar, IEC and Oehl, F and da Silva, GA}, title = {Edaphic Factors Influence the Distribution of Arbuscular Mycorrhizal Fungi Along an Altitudinal Gradient of a Tropical Mountain.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01354-2}, pmid = {30976842}, issn = {1432-184X}, abstract = {Changes in relief in montane areas, with increasing altitude, provide different biotic and abiotic conditions, acting on the species of arbuscular mycorrhizal fungi (AMF). The objective of this work was to determine the influence of altitude, edaphic factors, and vegetation on the AMF species in a mountainous area. The list of AMF species was obtained from morphological identification of the spores, with 72 species recovered from field samples and trap cultures. Lower levels of Shannon's diversity occurred only at lower altitude; however, there was no difference in AMF richness. The structure of the AMF assembly between the two highest altitudes was similar and differed in relation to the lower altitude. There was variation in the distribution of AMF species, which was related to soil texture and chemical factors along the altitude gradient. Some species, genera, and families were indicative of a certain altitude, showing the preference of fungi for certain environmental conditions, which may aid in decisions to conserve montane ecosystems.}, }
@article {pmid30976841, year = {2019}, author = {Sedlacek, CJ and McGowan, B and Suwa, Y and Sayavedra-Soto, L and Laanbroek, HJ and Stein, LY and Norton, JM and Klotz, MG and Bollmann, A}, title = {A Physiological and Genomic Comparison of Nitrosomonas Cluster 6a and 7 Ammonia-Oxidizing Bacteria.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01378-8}, pmid = {30976841}, issn = {1432-184X}, support = {1120443//National Science Foundation/ ; 0541797//National Science Foundation/ ; 0541797//National Science Foundation/ ; }, abstract = {Ammonia-oxidizing bacteria (AOB) within the genus Nitrosomonas perform the first step in nitrification, ammonia oxidation, and are found in diverse aquatic and terrestrial environments. Nitrosomonas AOB were grouped into six defined clusters, which correlate with physiological characteristics that contribute to adaptations to a variety of abiotic environmental factors. A fundamental physiological trait differentiating Nitrosomonas AOB is the adaptation to either low (cluster 6a) or high (cluster 7) ammonium concentrations. Here, we present physiological growth studies and genome analysis of Nitrosomonas cluster 6a and 7 AOB. Cluster 6a AOB displayed maximum growth rates at ≤ 1 mM ammonium, while cluster 7 AOB had maximum growth rates at ≥ 5 mM ammonium. In addition, cluster 7 AOB were more tolerant of high initial ammonium and nitrite concentrations than cluster 6a AOB. Cluster 6a AOB were completely inhibited by an initial nitrite concentration of 5 mM. Genomic comparisons were used to link genomic traits to observed physiological adaptations. Cluster 7 AOB encode a suite of genes related to nitrogen oxide detoxification and multiple terminal oxidases, which are absent in cluster 6a AOB. Cluster 6a AOB possess two distinct forms of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and select species encode genes for hydrogen or urea utilization. Several, but not all, cluster 6a AOB can utilize urea as a source of ammonium. Hence, although Nitrosomonas cluster 6a and 7 AOB have the capacity to fulfill the same functional role in microbial communities, i.e., ammonia oxidation, differentiating species-specific and cluster-conserved adaptations is crucial in understanding how AOB community succession can affect overall ecosystem function.}, }
@article {pmid30975748, year = {2019}, author = {Baker, JL and Hendrickson, EL and Tang, X and Lux, R and He, X and Edlund, A and McLean, JS and Shi, W}, title = {Klebsiella and Providencia emerge as lone survivors following long-term starvation of oral microbiota.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {17}, pages = {8499-8504}, doi = {10.1073/pnas.1820594116}, pmid = {30975748}, issn = {1091-6490}, support = {F32 DE026947/DE/NIDCR NIH HHS/United States ; R00 DE024543/DE/NIDCR NIH HHS/United States ; R01 DE020102/DE/NIDCR NIH HHS/United States ; R01 DE026186/DE/NIDCR NIH HHS/United States ; }, abstract = {It is well-understood that many bacteria have evolved to survive catastrophic events using a variety of mechanisms, which include expression of stress-response genes, quiescence, necrotrophy, and metabolic advantages obtained through mutation. However, the dynamics of individuals leveraging these abilities to gain a competitive advantage in an ecologically complex setting remain unstudied. In this study, we observed the saliva microbiome throughout the ecological perturbation of long-term starvation, allowing only the species best equipped to access and use the limited resources to survive. During the first several days, the community underwent a death phase that resulted in a ∼50-100-fold reduction in the number of viable cells. Interestingly, after this death phase, only three species, Klebsiella pneumoniae, Klebsiella oxytoca, and Providencia alcalifaciens, all members of the family Enterobacteriaceae, appeared to be transcriptionally active and recoverable. Klebsiella are significant human pathogens, frequently resistant to multiple antibiotics, and recently, ectopic colonization of the gut by oral Klebsiella was documented to induce dysbiosis and inflammation. MetaOmics analyses provided several leads for further investigation regarding the ecological success of the Enterobacteriaceae. The isolates accumulated single nucleotide polymorphisms in known growth advantage in stationary phase alleles and produced natural products closely resembling antimicrobial cyclic depsipeptides. The results presented in this study suggest that pathogenic Enterobacteriaceae persist much longer than their more benign neighbors in the salivary microbiome when faced with starvation. This is particularly significant, given that hospital surfaces contaminated with oral fluids, especially sinks and drains, are well-established sources of outbreaks of drug-resistant Enterobacteriaceae.}, }
@article {pmid30974353, year = {2019}, author = {Cahill, N and O'Connor, L and Mahon, B and Varley, Á and McGrath, E and Ryan, P and Cormican, M and Brehony, C and Jolley, KA and Maiden, MC and Brisse, S and Morris, D}, title = {Hospital effluent: A reservoir for carbapenemase-producing Enterobacterales?.}, journal = {The Science of the total environment}, volume = {672}, number = {}, pages = {618-624}, doi = {10.1016/j.scitotenv.2019.03.428}, pmid = {30974353}, issn = {1879-1026}, abstract = {Antimicrobial resistance is a major public health concern. Carbapenemase-producing Enterobacterales (CPE) represent a significant health threat as some strains are resistant to almost all available antibiotics. The aim of this research was to examine hospital effluent and municipal wastewater in an urban area in Ireland for CPE. Samples of hospital effluent (n = 5), municipal wastewater before (n = 5) and after (n = 4) the hospital effluent stream joined the municipal wastewater stream were collected over a nine-week period (May-June 2017). All samples were examined for CPE by direct plating onto Brilliance CRE agar. Isolates were selected for susceptibility testing to 15 antimicrobial agents in accordance with EUCAST criteria. Where relevant, isolates were tested for carbapenemase-encoding genes by real-time PCR. CPE were detected in five samples of hospital effluent, one sample of pre-hospital wastewater and three samples of post-hospital wastewater. Our findings suggest hospital effluent is a major contributor to CPE in municipal wastewater. Monitoring of hospital effluent for CPE could have important applications in detection and risk management of unrecognised dissemination of CPE in both the healthcare setting and the environment.}, }
@article {pmid30973888, year = {2019}, author = {Nakato, GV and Fuentes Rojas, JL and Verniere, C and Blondin, L and Coutinho, T and Mahuku, G and Wicker, E}, title = {A new Multi Locus Variable Number of Tandem Repeat Analysis Scheme for epidemiological surveillance of Xanthomonas vasicola pv. musacearum, the plant pathogen causing bacterial wilt on banana and enset.}, journal = {PloS one}, volume = {14}, number = {4}, pages = {e0215090}, doi = {10.1371/journal.pone.0215090}, pmid = {30973888}, issn = {1932-6203}, abstract = {Xanthomonas vasicola pv. musacearum (Xvm) which causes Xanthomonas wilt (XW) on banana (Musa accuminata x balbisiana) and enset (Ensete ventricosum), is closely related to the species Xanthomonas vasicola that contains the pathovars vasculorum (Xvv) and holcicola (Xvh), respectively pathogenic to sugarcane and sorghum. Xvm is considered a monomorphic bacterium whose intra-pathovar diversity remains poorly understood. With the sudden emergence of Xvm within east and central Africa coupled with the unknown origin of one of the two sublineages suggested for Xvm, attention has shifted to adapting technologies that focus on identifying the origin and distribution of the genetic diversity within this pathogen. Although microbiological and conventional molecular diagnostics have been useful in pathogen identification. Recent advances have ushered in an era of genomic epidemiology that aids in characterizing monomorphic pathogens. To unravel the origin and pathways of the recent emergence of XW in Eastern and Central Africa, there was a need for a genotyping tool adapted for molecular epidemiology. Multi-Locus Variable Number of Tandem Repeat Analysis (MLVA) is able to resolve the evolutionary patterns and invasion routes of a pathogen. In this study, we identified microsatellite loci from nine published Xvm genome sequences. Of the 36 detected microsatellite loci, 21 were selected for primer design and 19 determined to be highly typeable, specific, reproducible and polymorphic with two- to four- alleles per locus on a sub-collection. The 19 markers were multiplexed and applied to genotype 335 Xvm strains isolated from seven countries over several years. The microsatellite markers grouped the Xvm collection into three clusters; with two similar to the SNP-based sublineages 1 and 2 and a new cluster 3, revealing an unknown diversity in Ethiopia. Five of the 19 markers had alleles present in both Xvm and Xanthomonas vasicola pathovars holcicola and vasculorum, supporting the phylogenetic closeliness of these three pathovars. Thank to the public availability of the haplotypes on the MLVABank database, this highly reliable and polymorphic genotyping tool can be further used in a transnational surveillance network to monitor the spread and evolution of XW throughout Africa.. It will inform and guide management of Xvm both in banana-based and enset-based cropping systems. Due to the suitability of MLVA-19 markers for population genetic analyses, this genotyping tool will also be used in future microevolution studies.}, }
@article {pmid30973887, year = {2019}, author = {Perona-Vico, E and Blasco-Gómez, R and Colprim, J and Puig, S and Bañeras, L}, title = {[NiFe]-hydrogenases are constitutively expressed in an enriched Methanobacterium sp. population during electromethanogenesis.}, journal = {PloS one}, volume = {14}, number = {4}, pages = {e0215029}, doi = {10.1371/journal.pone.0215029}, pmid = {30973887}, issn = {1932-6203}, abstract = {Electromethanogenesis is the bioreduction of carbon dioxide (CO2) to methane (CH4) utilizing an electrode as electron donor. Some studies have reported the active participation of Methanobacterium sp. in electron capturing, although no conclusive results are available. In this study, we aimed at determining short-time changes in the expression levels of [NiFe]-hydrogenases (Eha, Ehb and Mvh), heterodisulfide reductase (Hdr), coenzyme F420-reducing [NiFe]-hydrogenase (Frh), and hydrogenase maturation protein (HypD), according to the electron flow in independently connected carbon cloth cathodes poised at- 800 mV vs. standard hydrogen electrode (SHE). Amplicon massive sequencing of cathode biofilm confirmed the presence of an enriched Methanobacterium sp. population (>70% of sequence reads), which remained in an active state (78% of cDNA reads), tagging this archaeon as the main methane producer in the system. Quantitative RT-PCR determinations of ehaB, ehbL, mvhA, hdrA, frhA, and hypD genes resulted in only slight (up to 1.5 fold) changes for four out of six genes analyzed when cells were exposed to open (disconnected) or closed (connected) electric circuit events. The presented results suggested that suspected mechanisms for electron capturing were not regulated at the transcriptional level in Methanobacterium sp. for short time exposures of the cells to connected-disconnected circuits. Additional tests are needed in order to confirm proteins that participate in electron capturing in Methanobacterium sp.}, }
@article {pmid30972435, year = {2019}, author = {Wei, W and Wang, N and Cai, L and Zhang, C and Jiao, N and Zhang, R}, title = {Impacts of Freshwater and Seawater Mixing on the Production and Decay of Virioplankton in a Subtropical Estuary.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01362-2}, pmid = {30972435}, issn = {1432-184X}, support = {41522603//National Natural Science Foundation of China/ ; 31570172//National Natural Science Foundation of China/ ; 91428308//National Natural Science Foundation of China/ ; 41673073//National Natural Science Foundation of China/ ; 41861144018//National Natural Science Foundation of China/ ; QNLM2016ORP0303//Qingdao National Laboratory for Marine Science and Technology/ ; }, abstract = {Virioplankton is an important component of the aquatic ecosystem and plays multiple ecological and biogeochemical roles. Although the spatial and temporal distributions and dynamics of virioplankton have been well investigated in riverine and marine environments, little is known about the dynamics and environmental controlling mechanisms of virioplankton in estuaries. In this study, viral abundance, production and decay were examined in the Pearl River Estuary (PRE), one of the largest estuaries in China. The influences of freshwater and seawater mixing on viral ecological dynamics were evaluated with several cross-transplant experiments. In PRE, viral abundance, production and decay rates varied from 2.72 ± 0.09 to 27.5 ± 1.07 × 106 viruses ml-1, 7.98 ± 2.33 to 16.27 ± 2.85% h-1 and 0.80 ± 0.23 to 3.74 ± 0.98% h-1, respectively. When the riverine and marine microbial community were transferred into simulated brackish water, viral production rates were markedly inhibited by 83.8% and 47.3%, respectively. The decay of riverine and marine virioplankton was inhibited by 21.1% and 34.2%, respectively, in simulated brackish water. These results indicate change of estuarine environmental factors significantly alters the dynamics of riverine and marine virioplankton. In addition, the effects of mixing on viral production and decay differed between high- and low-fluorescence viruses. High-fluorescence viruses seemed more resistant to decay than low-fluorescence viruses, whereas the production of marine low-fluorescence viruses seemed more resistant to inhibition than that of marine high-fluorescence viruses. Together, these results provide new insights into the ecological dynamics of virioplankton in estuarine environments.}, }
@article {pmid30967122, year = {2019}, author = {Ai, D and Li, X and Pan, H and Chen, J and Cram, JA and Xia, LC}, title = {Explore mediated co-varying dynamics in microbial community using integrated local similarity and liquid association analysis.}, journal = {BMC genomics}, volume = {20}, number = {Suppl 2}, pages = {185}, doi = {10.1186/s12864-019-5469-8}, pmid = {30967122}, issn = {1471-2164}, abstract = {BACKGROUND: Discovering the key microbial species and environmental factors of microbial community and characterizing their relationships with other members are critical to ecosystem studies. The microbial co-occurrence patterns across a variety of environmental settings have been extensively characterized. However, previous studies were limited by their restriction toward pairwise relationships, while there was ample evidence of third-party mediated co-occurrence in microbial communities.<br><br>METHODS: We implemented and applied the triplet-based liquid association analysis in combination with the local similarity analysis procedure to microbial ecology data. We developed an intuitive scheme to visualize those complex triplet associations along with pairwise correlations. Using a time series from the marine microbial ecosystem as example, we identified pairs of operational taxonomic units (OTUs) where the strength of their associations appeared to relate to the values of a third &quot;mediator&quot; variable. These &quot;mediator&quot; variables appear to modulate the associations between pairs of bacteria.<br><br>RESULTS: Using this analysis, we were able to assess the OTUs' ability to regulate its functional partners in the community, typically not manifested in the pairwise correlation patterns. For example, we identified Flavobacteria as a multifaceted player in the marine microbial ecosystem, and its clades were involved in mediating other OTU pairs. By contrast, SAR11 clades were not active mediators of the community, despite being abundant and highly correlated with other OTUs. Our results suggested that Flavobacteria are more likely to respond to situations where particles and unusual sources of dissolved organic material are prevalent, such as after a plankton bloom. On the other hand, SAR11s are oligotrophic chemoheterotrophs with inflexible metabolisms, and their relationships with other organisms may be less governed by environmental or biological factors.<br><br>CONCLUSIONS: By integrating liquid association with local similarity analysis to explore the mediated co-varying dynamics, we presented a novel perspective and a useful toolkit to analyze and interpret time series data from microbial community. Our augmented association network analysis is thus more representative of the true underlying dynamic structure of the microbial community. The analytic software in this study was implemented as new functionalities of the ELSA (Extended local similarity analysis) tool, which is available for free download (http://bitbucket.org/charade/elsa).}, }
@article {pmid30963868, year = {2019}, author = {Barbaro, L and Allan, E and Ampoorter, E and Castagneyrol, B and Charbonnier, Y and De Wandeler, H and Kerbiriou, C and Milligan, HT and Vialatte, A and Carnol, M and Deconchat, M and De Smedt, P and Jactel, H and Koricheva, J and Le Viol, I and Muys, B and Scherer-Lorenzen, M and Verheyen, K and van der Plas, F}, title = {Biotic predictors complement models of bat and bird responses to climate and tree diversity in European forests.}, journal = {Proceedings. Biological sciences}, volume = {286}, number = {1894}, pages = {20182193}, doi = {10.1098/rspb.2018.2193}, pmid = {30963868}, issn = {1471-2954}, abstract = {Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature forests replicated in six European countries from Spain to Finland, to investigate the importance of biotic predictors (i.e. the abundance or activity of defoliating insects, spiders, earthworms and wild ungulates) for bat and bird taxonomic and functional diversity. We found that nine out of 12 bird and bat diversity metrics were best explained when biotic factors were added to models including climate and habitat variables, with a mean gain in explained variance of 38% for birds and 15% for bats. Tree functional diversity was the most important habitat predictor for birds, while bats responded more to understorey structure. The best biotic predictors for birds were spider abundance and defoliating insect activity, while only bat functional evenness responded positively to insect herbivory. Accounting for potential biotic interactions between bats, birds and other taxa of lower trophic levels will help to understand how environmental changes along large biogeographical gradients affect higher-level predator diversity in forest ecosystems.}, }
@article {pmid30962365, year = {2019}, author = {Tveit, AT and Hestnes, AG and Robinson, SL and Schintlmeister, A and Dedysh, SN and Jehmlich, N and von Bergen, M and Herbold, C and Wagner, M and Richter, A and Svenning, MM}, title = {Widespread soil bacterium that oxidizes atmospheric methane.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {17}, pages = {8515-8524}, doi = {10.1073/pnas.1817812116}, pmid = {30962365}, issn = {1091-6490}, abstract = {The global atmospheric level of methane (CH4), the second most important greenhouse gas, is currently increasing by ∼10 million tons per year. Microbial oxidation in unsaturated soils is the only known biological process that removes CH4 from the atmosphere, but so far, bacteria that can grow on atmospheric CH4 have eluded all cultivation efforts. In this study, we have isolated a pure culture of a bacterium, strain MG08 that grows on air at atmospheric concentrations of CH4 [1.86 parts per million volume (p.p.m.v.)]. This organism, named Methylocapsa gorgona, is globally distributed in soils and closely related to uncultured members of the upland soil cluster α. CH4 oxidation experiments and 13C-single cell isotope analyses demonstrated that it oxidizes atmospheric CH4 aerobically and assimilates carbon from both CH4 and CO2 Its estimated specific affinity for CH4 (a0s) is the highest for any cultivated methanotroph. However, growth on ambient air was also confirmed for Methylocapsa acidiphila and Methylocapsa aurea, close relatives with a lower specific affinity for CH4, suggesting that the ability to utilize atmospheric CH4 for growth is more widespread than previously believed. The closed genome of M. gorgona MG08 encodes a single particulate methane monooxygenase, the serine cycle for assimilation of carbon from CH4 and CO2, and CO2 fixation via the recently postulated reductive glycine pathway. It also fixes dinitrogen and expresses the genes for a high-affinity hydrogenase and carbon monoxide dehydrogenase, suggesting that atmospheric CH4 oxidizers harvest additional energy from oxidation of the atmospheric trace gases carbon monoxide (0.2 p.p.m.v.) and hydrogen (0.5 p.p.m.v.).}, }
@article {pmid30961521, year = {2019}, author = {Dos Santos, HRM and Argolo, CS and Argôlo-Filho, RC and Loguercio, LL}, title = {A 16S rDNA PCR-based theoretical to actual delta approach on culturable mock communities revealed severe losses of diversity information.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {74}, doi = {10.1186/s12866-019-1446-2}, pmid = {30961521}, issn = {1471-2180}, abstract = {BACKGROUND: Subunits of ribosomal RNA genes (rDNAs) characterized by PCR-based protocols have been the proxy for studies in microbial taxonomy, phylogenetics, evolution and ecology. However, relevant factors have shown to interfere in the experimental outputs in a variety of systems. In this work, a 'theoretical' to 'actual' delta approach was applied to data on culturable mock bacterial communities (MBCs) to study the levels of losses in operational taxonomic units (OTUs) detectability. Computational and lab-bench strategies based on 16S rDNA amplification by 799F and U1492R primers were employed, using a fingerprinting method with highly improved detectability of fragments as a case-study tool. MBCs were of two major types: in silico MBCs, assembled with database-retrieved sequences, and in vitro MBCs, with AluI digestions of PCR data generated from culturable endophytes isolated from cacao trees.<br><br>RESULTS: Interfering factors for the 16 s rDNA amplifications, such as the type of template, direct and nested PCR, proportion of chloroplast DNA from a tropical plant source (Virola officinalis), and biased-amplification by the primers resulted in altered bacterial 16S rDNA amplification, both on MBCs and V. officinalis leaf-extracted DNA. For the theoretical data, the maximum number of fragments for in silico and in vitro cuts were not significantly different from each other. Primers' preferences for certain sequences were detected, depending on the MBCs' composition prior to PCR. The results indicated overall losses from 2.3 up to 8.2 times in the number of OTUs detected from actual AluI digestions of MBCs when compared to in silico and in vitro theoretical data.<br><br>CONCLUSIONS: Due to all those effects, the final amplification profile of the bacterial community assembled was remarkably simplified when compared to the expected number of detectable fragments known to be present in the MBC. From these findings, the scope of hypotheses generation and conclusions from experiments based on PCR amplifications of bacterial communities was discussed.}, }
@article {pmid30958642, year = {2019}, author = {Kim, J and Gómez-Pastora, J and Weigand, M and Potgieter, M and A Walters, N and Reátegui, E and F Palmer, A and Yazer, M and Zborowski, M and Chalmers, JJ}, title = {A Subpopulation of Monocytes in Normal Human Blood Has Significant Magnetic Susceptibility: Quantification and Potential Implications.}, journal = {Cytometry. Part A : the journal of the International Society for Analytical Cytology}, volume = {95}, number = {5}, pages = {478-487}, doi = {10.1002/cyto.a.23755}, pmid = {30958642}, issn = {1552-4930}, support = {BAA07-21//Defense Advanced Research Projects Agency/ ; 1R01HL131720-01A1//National Heart, Lung, and Blood Institute/ ; }, abstract = {The presence of iron in circulating monocytes is well known as they play essential roles in iron recycling. Also, the storage of this metal as well as its incorrect uptake and/or release are important data to diagnose different pathologies. It has been demonstrated that iron storage in human blood cells can be measured through their magnetic behavior with high accuracy; however, the magnetic characteristics of monocytes have not been reported so far to the best of our knowledge. Therefore, in this work, we report, for the first time, the physical and magnetic properties of human monocytes, along with plasma platelets, oxyhemoglobin red blood cells (oxyHb-RBCs), and methemoglobin red blood cells (metHb-RBCs). The different cell populations were separated by Ficoll-density gradient centrifugation, followed by a flow sorting step to isolate monocytes from peripheral blood mononuclear cells. The different fractions were analyzed by Coulter Counter (for determining the size distribution and concentration) and the sorted monocytes were qualitatively analyzed on ImageStream, a state-of-the-art imaging cytometer. The analysis of the Coulter Counter and ImageStream data suggests that although there exists contamination in the monocyte fraction, the integrity of the sorted monocytes appears to be intact and the concentration was high enough to precisely measure their magnetic velocity by Cell Tracking Velocimetry. Surprisingly, monocytes reported the highest magnetic mobility from the four fractions under analysis, with an average magnetic velocity 7.8 times higher than MetHb-RBCs, which is the only type of cells with positive magnetic velocities. This value is equivalent to a susceptibility 2.5 times higher than the value reported by fresh MetHb-RBCs. It should be noted that this is the first study that reports that a subpopulation of human monocytes is much more magnetic than MetHb-RBCs, opening the door to the possible isolation of human monocytes by label-free magnetic techniques. Further, it is suggested that these magnetic monocytes could &quot;contaminate&quot; positively selected, immunomagnetically labeled blood cells (i.e., during a process using magnetically conjugated antibodies targeting cells, such as CD34 positive cells). Conversely, these magnetic monocytes could be inadvertently removed from a desired blood population when one is using a negative magnetic isolation technique to target cells for removal. © 2019 International Society for Advancement of Cytometry.}, }
@article {pmid30957419, year = {2019}, author = {Fanin, N and Kardol, P and Farrell, M and Kempel, A and Ciobanu, M and Nilsson, MC and Gundale, MJ and Wardle, DA}, title = {Effects of plant functional group removal on structure and function of soil communities across contrasting ecosystems.}, journal = {Ecology letters}, volume = {}, number = {}, pages = {}, doi = {10.1111/ele.13266}, pmid = {30957419}, issn = {1461-0248}, support = {//Vetenskapsrådet/ ; }, abstract = {Loss of plant diversity has an impact on ecosystems worldwide, but we lack a mechanistic understanding of how this loss may influence below-ground biota and ecosystem functions across contrasting ecosystems in the long term. We used the longest running biodiversity manipulation experiment across contrasting ecosystems in existence to explore the below-ground consequences of 19 years of plant functional group removals for each of 30 contrasting forested lake islands in northern Sweden. We found that, against expectations, the effects of plant removals on the communities of key groups of soil organisms (bacteria, fungi and nematodes), and organic matter quality and soil ecosystem functioning (decomposition and microbial activity) were relatively similar among islands that varied greatly in productivity and soil fertility. This highlights that, in contrast to what has been shown for plant productivity, plant biodiversity loss effects on below-ground functions can be relatively insensitive to environmental context or variation among widely contrasting ecosystems.}, }
@article {pmid30956127, year = {2019}, author = {Abad, ED and Ferreira, DC and Cavalcante, FS and Saintive, S and Goudouris, E and Prado, EA and Hofer, C and Ribeiro, M and da Silva, AMP and Rosado, AS and van Elsas, JD and Dos Santos, KRN}, title = {High incidence of acquiring methicillin-resistant Staphylococcus aureus in Brazilian children with Atopic Dermatitis and associated risk factors.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jmii.2018.12.014}, pmid = {30956127}, issn = {1995-9133}, abstract = {BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) colonization in Atopic Dermatitis (AD) patients can contribute to worsening their clinical condition.<br><br>OBJECTIVE: A cohort study was carried out to determine the incidence of MRSA acquisition and its risk factors in AD children.<br><br>METHODS: Patients with AD (2 months-14 years old) were followed up for about 1 year at a reference center for AD treatment in Rio de Janeiro, Brazil, from September 2011 to February 2014. Nasal swabs from patients and contacts were collected every 2 months. The SCORAD system assessed the severity of the AD. S. aureus isolates were evaluated to determine the methicillin resistance and the clonal lineages.<br><br>RESULTS: Among 117 AD patients, 97 (82.9%) were already colonized with S. aureus and 26 (22.2%) had MRSA at the first evaluation. The incidence of MRSA acquisition in the cohort study was 27.47% (n = 25). The SCORAD assessments were: mild (46.15%), moderate (37.36%) or severe (16.48%). Risk factors were: colonized MRSA contacts (HR = 2.27; 95% CI: 1.16-7.54), use of cyclosporine (HR = 5.84; 95% CI: 1.70-19.98), moderate or severe AD (HR = 3.26; 95% CI: 1.13-9.37). Protective factors were: availability of running water (HR = 0.21; 95% CI: 0.049-0.96) and use of antihistamines (HR = 0.21; 95% IC: 0.64-0.75). MRSA isolates carried the SCCmec type IV and most of them were typed as USA800/ST5.<br><br>CONCLUSIONS: The high incidence of MRSA acquisition found among AD patients and the risk factors associated show that an effective surveillance of MRSA colonization in these patients is needed.}, }
@article {pmid30955771, year = {2019}, author = {Cotta, SR and Cadete, LL and van Elsas, JD and Andreote, FD and Dias, ACF}, title = {Exploring bacterial functionality in mangrove sediments and its capability to overcome anthropogenic activity.}, journal = {Marine pollution bulletin}, volume = {141}, number = {}, pages = {586-594}, doi = {10.1016/j.marpolbul.2019.03.001}, pmid = {30955771}, issn = {1879-3363}, mesh = {Bacteria/genetics/metabolism ; Biodiversity ; Brazil ; Carbon/metabolism ; Ecosystem ; Gene Transfer, Horizontal ; Geologic Sediments/*microbiology ; Metagenomics ; *Microbiota/genetics ; Sulfur/metabolism ; *Wetlands ; }, abstract = {Mangrove forests are highly productive yet vulnerable ecosystems that act as important carbon sinks (&quot;blue carbon&quot;). The objective of this work was to analyze the impact of anthropogenic activities on microbiome structure and functioning. The metagenomic analysis revealed that the taxonomic compositions were grossly similar across all mangrove microbiomes. Remarkably, these microbiomes, along the gradient of anthropogenic impact, showed fluctuations in the relative abundances of bacterial taxa predicted to be involved in sulfur cycling processes. Functions involved in sulfur metabolism, such as APS pathways (associated with sulfate reduction and sulfur oxidation processes) were prevalent across the microbiomes, being sox and dsrAB genes highly expressed on anthropogenically-impacted areas. Apparently, the oil-impacted microbiomes were more affected in taxonomic than in functional terms, as high functional redundancies were noted across them. The microbial gene diversity found was typical for a functional system, even following the previous disturbance.}, }
@article {pmid30953090, year = {2019}, author = {Stamou, GP and Monokrousos, N and Gwynn-Jones, D and Whitworth, DE and Papatheodorou, EM}, title = {A Polyphasic Approach for Assessing Eco-System Connectivity Demonstrates that Perturbation Remodels Network Architecture in Soil Microcosms.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01367-x}, pmid = {30953090}, issn = {1432-184X}, support = {No. Project 89434//Research Committee, Aristotle University of Thessaloniki/ ; }, abstract = {Network analysis was used to show changes in network attributes by analyzing the relations among the main soil microbial groups in a potted tomato soil inoculated with arbuscular mycorrhizal fungus, treated with low doses of Mentha spicata essential oil, or both, and then exposed to tenfold higher oil addition (stress pulse). Pretreatments were chosen since they can induce changes in the composition of the microbial community. Cellular phospholipid fatty acids (PLFAs) and the activity of six soil enzymes, mainly involved in the N-cycle were measured. Networks were constructed based on correlated changes in PLFA abundances. The values of all parameters were significantly different from those of random networks indicating modular architecture. Networks ranked from the lowest to highest modularity: control, non-pretreated and stressed, inoculated and stressed, oil treated and stressed, inoculated and treated with oil and stressed. The high values of network density and 1st/2nd eigenvalue ratio are related to arylamidase activity while N-acetyl-glucosaminidase, acid phosphomoesterase, and asparaginase activities related to high values of the clustering coefficient index. We concluded that modularity may be an efficient indicator of changes in the network of interactions among the members of the soil microbial community and the modular structure of the network may be related to the activity of specific enzymes. Communities that were stressed without a pretreatment were relatively resistant but prone to sudden transition towards instability, while oil or inoculation pretreatments gave networks which could be considered adaptable and susceptible to gradual change.}, }
@article {pmid30953089, year = {2019}, author = {Han, J and Wang, S and Fan, D and Guo, Y and Liu, C and Zhu, Y}, title = {Time-Dependent Hormetic Response of Soil Alkaline Phosphatase Induced by Cd and the Association with Bacterial Community Composition.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01371-1}, pmid = {30953089}, issn = {1432-184X}, support = {No. 41375149//National Natural Science Foundation of China/ ; No. 41471191//National Natural Science Foundation of China/ ; }, abstract = {Hormetic dose-response that involved Cd in soils is increasingly paid attentions for risk assessment of Cd toxicity, but insufficient studies were conducted to define the temporary modification of soil enzyme and the potential microbial responses. The present study chooses soil alkaline phosphatase (ALP) as endpoint to uncover the time-dependent hormetic responses to low doses of Cd and its association with bacterial community composition. The results showed that addition of 0.01-3.0 mg kg-1 Cd significantly increased ALP's activities with maximum stimulatory magnitude of 11.4-27.2%, indicating a typical hormesis. The response started at 12 h after Cd addition and maintained about 24 h. This demonstrated that the hormetic response is time-dependent and transient. Changes of soil bacterial community composition showed that, at 6 h, relative abundances (RAs) of Proteobacteria and Firmicutes at phylum and Pontibacter, Bacillaceae-Bacillus, Bacillaceae1-Bacillus, and Paenisporosarcina at genus significantly correlated with ALP's activities at 12-36 h (P < 0.05). This suggests that soil bacteria likely showed an earlier response to Cd and potentially contributes to the subsequent soil enzyme's hormesis. In addition, it was found that Gram-negative bacteria other than Gram-positive bacteria are prone to exhibiting a hormetic response under Cd stress. Our findings provide much insight into ecotoxicological risk assessment for soil Cd pollution.}, }
@article {pmid30952994, year = {2019}, author = {Martiny, AC}, title = {High proportions of bacteria are culturable across major biomes.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0410-3}, pmid = {30952994}, issn = {1751-7370}, support = {1848576//NSF | Directorate for Geosciences (GEO)/ ; 1559002//NSF | Directorate for Geosciences (GEO)/ ; 1457160//NSF | BIO | Division of Environmental Biology (DEB)/ ; SC0016410//DOE | SC | Biological and Environmental Research (BER)/ ; }, abstract = {The paradigm that only 1% of microbes are culturable has had a profound impact on our understanding of microbial ecology and is still a major motivation for mostly using molecular tools to characterize microbial communities. However, this point is often expressed vaguely, suggesting that some scientists have different interpretations of the paradigm. In addition, there have been substantial advances in cultivation techniques suggesting that this paradigm may no longer be correct. To quantify bacterial culturability across six major biomes, I found that the median 16S rRNA similarity of bacteria to known cultured relatives was 97.3 ± 2.3% (s.d.). Furthermore, 52.0 ± 24% of sequences and 34.9 ± 23% of taxa (defined as >97% similar) had a closely related cultured relative. Thus, many cells and taxa across environments are culturable with known techniques, suggesting that the 1% paradigm is no longer correct.}, }
@article {pmid30952863, year = {2019}, author = {Wilschut, RA and van der Putten, WH and Garbeva, P and Harkes, P and Konings, W and Kulkarni, P and Martens, H and Geisen, S}, title = {Root traits and belowground herbivores relate to plant-soil feedback variation among congeners.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {1564}, doi = {10.1038/s41467-019-09615-x}, pmid = {30952863}, issn = {2041-1723}, mesh = {Animals ; Geranium/genetics/microbiology/*physiology ; Herbivory/*physiology ; Microbiota ; Nematoda/physiology ; Phylogeny ; Plant Roots/genetics/microbiology/physiology ; Rhizosphere ; *Soil ; }, abstract = {Plant-soil feedbacks contribute to vegetation dynamics by species-specific interactions between plants and soil biota. Variation in plant-soil feedbacks can be predicted by root traits, successional position, and plant nativeness. However, it is unknown whether closely related plant species develop more similar plant-soil feedbacks than more distantly related species. Where previous comparisons included plant species from distant phylogenetic positions, we studied plant-soil feedbacks of congeneric species. Using eight intra-continentally range-expanding and native Geranium species, we tested relations between phylogenetic distances, chemical and structural root traits, root microbiomes, and plant-soil feedbacks. We show that root chemistry and specific root length better predict bacterial and fungal community composition than phylogenetic distance. Negative plant-soil feedback strength correlates with root-feeding nematode numbers, whereas microbiome dissimilarity, nativeness, or phylogeny does not predict plant-soil feedbacks. We conclude that root microbiome variation among congeners is best explained by root traits, and that root-feeding nematode abundances predict plant-soil feedbacks.}, }
@article {pmid30951891, year = {2019}, author = {Philip, N and Bandara, HMHN and Leishman, SJ and Walsh, LJ}, title = {Effect of polyphenol-rich cranberry extracts on cariogenic biofilm properties and microbial composition of polymicrobial biofilms.}, journal = {Archives of oral biology}, volume = {102}, number = {}, pages = {1-6}, doi = {10.1016/j.archoralbio.2019.03.026}, pmid = {30951891}, issn = {1879-1506}, abstract = {OBJECTIVE: To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria.<br><br>METHODS: Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated for 2 min every 12 h over the entire biofilm growth period with 500 μg/mL cranberry extract or vehicle control. The effect of the cranberry extract on biofilm behaviour was evaluated using different assays and its influence on key cariogenic and health-associated bacterial populations was assessed with a microarray real-time quantitative PCR method.<br><br>RESULTS: Cranberry-treated biofilms showed significant drops in biomass (38% reduction, P < 0.001), acidogenicity (44% reduction, P < 0.001), EPS/microbial biovolume ratios (P = 0.033), and CFU counts (51% reduction, P = 0.001). Furthermore, the cranberry extracts effected a significantly lower relative abundance of caries-associated Streptococcus sobrinus (fold change 0.004, P = 0.002) and Provotella denticola (0.002, P < 0.001), and a significantly higher relative abundance of the health-associated Streptococcus sanguinis (fold change 90.715, P = 0.001).<br><br>CONCLUSIONS: The cranberry extract lowered biofilm biomass, acidogenicity, EPS/microbial biovolumes, CFU counts, and modulated a beneficial microbial ecological change in saliva-derived polymicrobial biofilms.}, }
@article {pmid30949751, year = {2019}, author = {Hughey, MC and Sokol, ER and Walke, JB and Becker, MH and Belden, LK}, title = {Ecological Correlates of Large-Scale Turnover in the Dominant Members of Pseudacris crucifer Skin Bacterial Communities.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01372-0}, pmid = {30949751}, issn = {1432-184X}, support = {DEB-1136640//National Science Foundation/ ; D10ZO-028//Morris Animal Foundation/ ; }, abstract = {Animals host a wide diversity of symbiotic microorganisms that contribute important functions to host health, and our knowledge of what drives variation in the composition of these complex communities continues to grow. Microbiome studies at larger spatial scales present opportunities to evaluate the contribution of large-scale factors to variation in the microbiome. We conducted a large-scale field study to assess variation in the bacterial symbiont communities on adult frog skin (Pseudacris crucifer), characterized using 16S rRNA gene amplicon sequencing. We found that skin bacterial communities on frogs were less diverse than, and structurally distinct from, the surrounding habitat. Frog skin was typically dominated by one of two bacterial OTUs: at western sites, a Proteobacteria dominated the community, whereas eastern sites were dominated by an Actinobacteria. Using a metacommunity framework, we then sought to identify factors explaining small- and large-scale variation in community structure-that is, among hosts within a pond, and among ponds spanning the study transect. We focused on the presence of a fungal skin pathogen, Batrachochytrium dendrobatidis (Bd) as one potential driver of variation. We found no direct link between skin bacterial community structure and Bd infection status of individual frog hosts. Differences in pond-level community structure, however, were explained by Bd infection prevalence. Importantly, Bd infection prevalence itself was correlated with numerous other environmental factors; thus, skin bacterial diversity may be influenced by a complex suite of extrinsic factors. Our findings indicate that large-scale factors and processes merit consideration when seeking to understand microbiome diversity.}, }
@article {pmid30949750, year = {2019}, author = {Lan, S and Thomas, AD and Tooth, S and Wu, L and Hu, C}, title = {Small-Scale Spatial Heterogeneity of Photosynthetic Fluorescence Associated with Biological Soil Crust Succession in the Tengger Desert, China.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01356-0}, pmid = {30949750}, issn = {1432-184X}, support = {31670456 and 31300322//National Natural Science Foundation of China/ ; 2017385//Youth Innovation Promotion Association of the Chinese Academy of Sciences/ ; 663830//European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant/ ; }, abstract = {In dryland regions, biological soil crusts (BSCs) have numerous important ecosystem functions. Crust species and functions are, however, highly spatially heterogeneous and remain poorly understood at a range of scales. In this study, chlorophyll fluorescence imaging was used to quantify millimeter-scale patterns in the distribution and activity of photosynthetic organisms in BSCs of different successional stages (including cyanobacterial, lichen, moss three main successional stages and three intermixed transitional stages) from the Tengger Desert, China. Chlorophyll fluorescence images derived from the Imaging PAM (Pulse Amplitude Modulation) showed that with the succession from cyanobacterial to lichen and to moss crusts, crust photosynthetic efficiency (including the maximum and effective photosynthetic efficiency, respectively) and fluorescence coverage increased significantly (P < 0.05), and that increasing photosynthetically active radiation (PAR) reduced the effective photosynthetic efficiency (Yield). The distribution of photosynthetic organisms in crusts determined Fv/Fm (ratio of variable fluorescence to maximum fluorescence) frequency pattern, although the photosynthetic heterogeneity (SHI index) was not significantly different (P > 0.05) between cyanobacterial and moss crusts, and showed a unimodal pattern of Fv/Fm values. In contrast, photosynthetic heterogeneity was significantly higher in lichen, cyanobacteria-moss and lichen-moss crusts (P < 0.05), with a bimodal pattern of Fv/Fm values. Point pattern analysis showed that the distribution pattern of chlorophyll fluorescence varied at different spatial scales and also among the different crust types. These new results provide a detailed (millimeter-scale) insight into crust photosynthetic mechanisms and spatial distribution patterns associated with their community types. Collectively, this information provides an improved theoretical basis for crust maintenance and management in dryland regions.}, }
@article {pmid30948795, year = {2019}, author = {D'Amico, F and Soverini, M and Zama, D and Consolandi, C and Severgnini, M and Prete, A and Pession, A and Barone, M and Turroni, S and Biagi, E and Brigidi, P and Masetti, R and Rampelli, S and Candela, M}, title = {Gut resistome plasticity in pediatric patients undergoing hematopoietic stem cell transplantation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {5649}, doi = {10.1038/s41598-019-42222-w}, pmid = {30948795}, issn = {2045-2322}, abstract = {The gut microbiome of pediatric patients undergoing allo-hematopoietic stem cell transplantation (HSCT) has recently been considered as a potential reservoir of antimicrobial resistance, with important implications in terms of patient mortality rate. By means of shotgun metagenomics, here we explored the dynamics of the gut resistome - i.e. the pattern of antibiotic resistance genes provided by the gut microbiome - in eight pediatric patients undergoing HSCT, half of whom developed acute Graft-versus-Host Disease (aGvHD). According to our findings, the patients developing aGvHD are characterized by post-HSCT expansion of their gut resistome, involving the acquisition of new resistances, as well as the consolidation of those already present before HSCT. Interestingly, the aGvHD-associated bloom in resistome diversity is not limited to genes coding for resistance to the antibiotics administered along the therapeutic course, but rather involves a broad pattern of different resistance classes, including multidrug resistance, as well as resistance to macrolides, aminoglycosides, tetracyclines and beta-lactams. Our data stress the relevance of mapping the gut resistome in HSCT pediatric patients to define the most appropriate anti-infective treatment post HSCT.}, }
@article {pmid30945554, year = {2019}, author = {Miclotte, L and Van de Wiele, T}, title = {Food processing, gut microbiota and the globesity problem.}, journal = {Critical reviews in food science and nutrition}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/10408398.2019.1596878}, pmid = {30945554}, issn = {1549-7852}, abstract = {In the context of diseases of affluence, western diets have in the past years mainly been studied on their fat and sugar content and lack of dietary fiber. Yet, the more general aspect of food processing has recently sparked scientific interest as well. In addition, the gut microbiota have been put forward as an important link between diet, obesity and non-communicable diseases (NCD). Western dietary patterns, containing large amounts of processed foods might create an imbalance in the gut system by affecting gut bacteria and their metabolism. Here we discuss what has been already published regarding the relationship between several recently researched features of processed foods and the etiology of obesity and NCD. The addressed features concern micronutrient and energy density, several types of food additives and the generation of advanced glycation end products by thermal treatment during food processing. Overall, literature indicates that all discussed aspects can be linked to western ailments and that they can have a potential negative impact on human microbiota. Therefore, we propose that the thesis that a distressed gut microbiota is a mechanism that might explain how food processing features could harm human health is gaining empirical evidence. Future research will need to address the question whether the alteration of the gut microbiota is a direct or an indirect (via the host) effect. These conclusions are important assets in the fight against the continuing worldwide upsurge of obesity and NCD.}, }
@article {pmid30944882, year = {2019}, author = {Jiao, S and Xu, Y and Zhang, J and Hao, X and Lu, Y}, title = {Core Microbiota in Agricultural Soils and Their Potential Associations with Nutrient Cycling.}, journal = {mSystems}, volume = {4}, number = {2}, pages = {}, doi = {10.1128/mSystems.00313-18}, pmid = {30944882}, issn = {2379-5077}, abstract = {Revealing the ecological roles of the core microbiota in community maintaining and soil nutrient cycling is crucial for understanding ecosystem function, yet there is a dearth of continental-scale studies on this fundamental topic in microbial ecology. Here, we collected 251 soil samples from adjacent pairs of maize and rice fields at a continental scale in eastern China. We revealed the major ecological roles of the core microbiota in maintaining complex connections between bacterial taxa and their associations with belowground multinutrient cycling. By identifying the habitat preferences of the core microbiota, we built a continental atlas for mapping the spatial distributions of bacteria in agro-soils, which helps forecast the responses of agricultural ecosystems to anthropogenic disturbance. The multinutrient cycling index for maize and rice soils was related to bacterial α-diversity and β-diversity, respectively. Rice soils exhibited higher bacterial diversity and closer bacterial cooccurrence relationships than maize soils. In contrast to the macro- or microecological latitudinal richness patterns in natural terrestrial ecosystems, the bacteria in maize soils showed higher richness at high latitudes; however, this trend was not observed in rice soils. This study provides a new perspective on the distinct bacterial biogeographic patterns to predict the ecological roles of the core microbiota in agro-soils and thus helps manage soil bacterial communities for better provisioning of key ecosystem services. IMPORTANCE Disentangling the roles of the core microbiota in community maintaining and soil nutrient cycling is an important yet poorly understood topic in microbial ecology. This study presents an exploratory effort to gain predictive understanding of the spatial atlas and ecological roles of the core microbiota. A systematic, continental-scale survey was conducted using agro-soils in adjacent pairs of maize (dryland) and rice (wetland) fields across eastern China. The results indicate that the core microbiota play major ecological roles in maintaining complex connections between bacterial taxa and are associated with belowground multinutrient cycling. A continental atlas was built for mapping the bacterial spatial distributions in agro-soils through identifying their habitat preferences. This study represents a significant advance in forecasting the responses of agricultural ecosystems to anthropogenic disturbance and thus helps manage soil bacterial communities for better provisioning of key ecosystem services-the ultimate goal of microbial ecology.}, }
@article {pmid30944878, year = {2019}, author = {Tong, X and Leung, MHY and Wilkins, D and Cheung, HHL and Lee, PKH}, title = {Neutral Processes Drive Seasonal Assembly of the Skin Mycobiome.}, journal = {mSystems}, volume = {4}, number = {2}, pages = {}, doi = {10.1128/mSystems.00004-19}, pmid = {30944878}, issn = {2379-5077}, abstract = {The importance of microorganisms to human skin health has led to a growing interest in the temporal stability of skin microbiota. Here we investigated the dynamics and assembly of skin fungal communities (mycobiomes) with amplicon sequencing of samples collected from multiple sites on 24 healthy Chinese individuals across four seasons (in the order of winter, spring, summer, and autumn in a calendar year). We found a significant difference in community compositions between individuals, and intrapersonal community variation increased over time at all body sites. Within each season, the frequency of occurrence of most operational taxonomic units (OTUs) was well fitted by a neutral model, highlighting the importance of stochastic forces such as passive dispersal and ecological drift in skin community assembly. Despite the significant richness contributed by neutrally distributed OTUs, skin coassociation networks were dominated by taxa well-adapted to multiple body sites (forehead, forearm, and palm), although hub species were disproportionately rare. Taken together, these results suggest that while skin mycobiome assembly is a predominantly neutral process, taxa that could be under the influence of selective forces (e.g., host selection) are potentially key to the structure of a community network. IMPORTANCE Fungi are well recognized members of the human skin microbiota and are crucial to cutaneous health. Common cutaneous diseases such as seborrheic dermatitis and dermatophytes are linked to fungal species. Most studies related to skin microbial community dynamics have focused on Western subjects, while non-Western individuals are understudied. In this study, we explore the seasonal changes of the skin mycobiome in a healthy Chinese cohort and identify ecological processes that could possibly give rise to such variations. Our work reveals the dynamic nature of host skin fungal community, highlighting the dominant roles neutral forces play in the seasonal assembly of skin mycobiome. This study provides insight into the microbial ecology of the human skin microbiome and fills a knowledge gap in the literature regarding the dynamics of skin fungal community.}, }
@article {pmid30944853, year = {2019}, author = {Pärnänen, KMM and Narciso-da-Rocha, C and Kneis, D and Berendonk, TU and Cacace, D and Do, TT and Elpers, C and Fatta-Kassinos, D and Henriques, I and Jaeger, T and Karkman, A and Martinez, JL and Michael, SG and Michael-Kordatou, I and O'Sullivan, K and Rodriguez-Mozaz, S and Schwartz, T and Sheng, H and Sørum, H and Stedtfeld, RD and Tiedje, JM and Giustina, SVD and Walsh, F and Vaz-Moreira, I and Virta, M and Manaia, CM}, title = {Antibiotic resistance in European wastewater treatment plants mirrors the pattern of clinical antibiotic resistance prevalence.}, journal = {Science advances}, volume = {5}, number = {3}, pages = {eaau9124}, doi = {10.1126/sciadv.aau9124}, pmid = {30944853}, issn = {2375-2548}, abstract = {Integrated antibiotic resistance (AR) surveillance is one of the objectives of the World Health Organization global action plan on antimicrobial resistance. Urban wastewater treatment plants (UWTPs) are among the most important receptors and sources of environmental AR. On the basis of the consistent observation of an increasing north-to-south clinical AR prevalence in Europe, this study compared the influent and final effluent of 12 UWTPs located in seven countries (Portugal, Spain, Ireland, Cyprus, Germany, Finland, and Norway). Using highly parallel quantitative polymerase chain reaction, we analyzed 229 resistance genes and 25 mobile genetic elements. This first trans-Europe surveillance showed that UWTP AR profiles mirror the AR gradient observed in clinics. Antibiotic use, environmental temperature, and UWTP size were important factors related with resistance persistence and spread in the environment. These results highlight the need to implement regular surveillance and control measures, which may need to be appropriate for the geographic regions.}, }
@article {pmid30941803, year = {2019}, author = {Björk, JR and Dasari, M and Grieneisen, L and Archie, EA}, title = {Primate microbiomes over time: Longitudinal answers to standing questions in microbiome research.}, journal = {American journal of primatology}, volume = {}, number = {}, pages = {e22970}, doi = {10.1002/ajp.22970}, pmid = {30941803}, issn = {1098-2345}, abstract = {To date, most insights into the processes shaping vertebrate gut microbiomes have emerged from studies with cross-sectional designs. While this approach has been valuable, emerging time series analyses on vertebrate gut microbiomes show that gut microbial composition can change rapidly from 1 day to the next, with consequences for host physical functioning, health, and fitness. Hence, the next frontier of microbiome research will require longitudinal perspectives. Here we argue that primatologists, with their traditional focus on tracking the lives of individual animals and familiarity with longitudinal fecal sampling, are well positioned to conduct research at the forefront of gut microbiome dynamics. We begin by reviewing some of the most important ecological processes governing microbiome change over time, and briefly summarizing statistical challenges and approaches to microbiome time series analysis. We then introduce five questions of general interest to microbiome science where we think field-based primate studies are especially well positioned to fill major gaps: (a) Do early life events shape gut microbiome composition in adulthood? (b) Do shifting social landscapes cause gut microbial change? (c) Are gut microbiome phenotypes heritable across variable environments? (d) Does the gut microbiome show signs of host aging? And (e) do gut microbiome composition and dynamics predict host health and fitness? For all of these questions, we highlight areas where primatologists are uniquely positioned to make substantial contributions. We review preliminary evidence, discuss possible study designs, and suggest future directions.}, }
@article {pmid30941446, year = {2019}, author = {Johansen, R and Albright, M and Gallegos-Graves, V and Lopez, D and Runde, A and Yoshida, T and Dunbar, J}, title = {Tracking Replicate Divergence in Microbial Community Composition and Function in Experimental Microcosms.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01368-w}, pmid = {30941446}, issn = {1432-184X}, support = {SFA 2015F260//U.S. Department of Energy/ ; }, abstract = {The study of microbial community functions necessitates replicating microbial communities. Variation in community development over time renders this an imperfect process. Thus, anticipating the likely degree of variation among replicate communities may aid in experimental design. We examined divergence in replicate community composition and function among 128 naturally assembled starting communities obtained from soils, each replicated three times, following a 30-day microcosm incubation period. Bacterial and fungal communities diverged in both composition and function among replicates, but remained much more similar to each other than to communities from different starting inocula. Variation in bacterial community composition among replicates was, however, correlated with variation in dissolved organic carbon production. A smaller-scale experiment testing nine starting communities showed that divergence was similar whether replicates were incubated on sterile or non-sterile pine litter, suggesting the impact of a pre-existing community on replicate divergence is minor. However, replicates in this experiment which were incubated for 114 days diverged more than those incubated for 30 days, suggesting experiments that run over long time periods will likely see greater variation among replicate community composition. These results suggest that while replicates diverge at a community level, such divergence is unlikely to severely impede the study of community function.}, }
@article {pmid30937143, year = {2019}, author = {Chiu, CY and Chan, YL and Tsai, MH and Wang, CJ and Chiang, MH and Chiu, CC}, title = {Gut microbial dysbiosis is associated with allergen-specific IgE responses in young children with airway allergies.}, journal = {The World Allergy Organization journal}, volume = {12}, number = {3}, pages = {100021}, doi = {10.1016/j.waojou.2019.100021}, pmid = {30937143}, issn = {1939-4551}, abstract = {Background: There is increasing evidence linking alterations of the gut microbial composition during early infancy to the development of atopic diseases and asthma. However, few studies have addressed the association of dysbiotic gut microbiota with allergic reactions through evaluation of feces in young children with allergic airway diseases.<br><br>Methods: We sought to evaluate relationships among gut microbiota, total fecal immunoglobulin E (IgE) levels, serum allergic sensitization, and their relevance to childhood allergic rhinitis and asthma. Microbial composition and diversity were analyzed with Illumina-based 16S rRNA gene sequencing of 89 stool samples collected from children with asthma (n = 35) and allergic rhinitis (n = 28), and from healthy controls (n = 26). Data analysis was performed using Quantitative Insights into Microbial Ecology (QIIME) software.<br><br>Results: A significantly lower abundance of organisms of the phylum Firmicutes were found in children with asthma and allergic rhinitis than in the healthy controls. Relatively lower Chao1 and Shannon indices were also found in children with allergic airway diseases but without any significant difference. Total fecal IgE levels in early childhood were strongly correlated with serum D. pteronyssinus- and D. farinae-specific IgE but not with food-specific IgE levels. In comparison with healthy controls, the genus Dorea was less abundant and negatively correlated with total fecal IgE levels in children with rhinitis, whereas the genus Clostridium was abundant and positively correlated with fecal IgE levels in children with asthma.<br><br>Conclusions: An interaction between particular subsets of gut microbial dysbiosis and IgE-mediated responses to allergens may contribute to the susceptibility to allergic rhinitis and asthma in early childhood.}, }
@article {pmid30936485, year = {2019}, author = {Bulzu, PA and Andrei, AŞ and Salcher, MM and Mehrshad, M and Inoue, K and Kandori, H and Beja, O and Ghai, R and Banciu, HL}, title = {Casting light on Asgardarchaeota metabolism in a sunlit microoxic niche.}, journal = {Nature microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41564-019-0404-y}, pmid = {30936485}, issn = {2058-5276}, abstract = {Recent advances in phylogenomic analyses and increased genomic sampling of uncultured prokaryotic lineages have brought compelling evidence in support of the emergence of eukaryotes from within the archaeal domain of life (eocyte hypothesis)1,2. The discovery of Asgardarchaeota and its supposed position at the base of the eukaryotic tree of life3,4 provided cues about the long-awaited identity of the eocytic lineage from which the nucleated cells (Eukaryota) emerged. While it is apparent that Asgardarchaeota encode a plethora of eukaryotic-specific proteins (the highest number identified yet in prokaryotes)5, the lack of genomic information and metabolic characterization has precluded inferences about their lifestyles and the metabolic landscape that favoured the emergence of the protoeukaryote ancestor. Here, we use advanced phylogenetic analyses for inferring the deep ancestry of eukaryotes, and genome-scale metabolic reconstructions for shedding light on the metabolic milieu of Asgardarchaeota. In doing so, we: (1) show that Heimdallarchaeia (the closest eocytic lineage to eukaryotes to date) are likely to have a microoxic niche, based on their genomic potential, with aerobic metabolic pathways that are unique among Archaea (that is, the kynurenine pathway); (2) provide evidence of mixotrophy within Asgardarchaeota; and (3) describe a previously unknown family of rhodopsins encoded within the recovered genomes.}, }
@article {pmid30929045, year = {2019}, author = {Hogue, SR and Gomez, MF and da Silva, WV and Pierce, CM}, title = {A Customized At-Home Stool Collection Protocol for Use in Microbiome Studies Conducted in Cancer Patient Populations.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01346-2}, pmid = {30929045}, issn = {1432-184X}, support = {02-25999-18-46//Florida Academic Cancer Center Alliance/ ; P30-CA076292//H. Lee Moffitt Cancer Center and Research Institute/ ; }, abstract = {Fecal specimen collection in the clinical setting is often unfeasible for large population studies, especially because cancer patients on immunotherapy often experience constipation. A method for constructing and using an at-home stool collection kit designed for epidemiological studies in cancer patients is presented. Participation and compliance rates of the collection kit among late-stage cancer patients from an ongoing, longitudinal study are also discussed. The kit includes three different media on which samples are introduced. Using one stool sample, patients collect specimens by smearing stool onto a fecal occult blood test (FOBT) card, containing three slides for collection. Additional specimens from the same stool sample are added to one tube containing 8 mL of RNAlater preservative and one tube containing 8 mL of 95% ethanol. Stool specimens are stored at room temperature and returned to researchers within 3 days of collection. The purpose of this kit is to yield stool specimens on a variety of media that can be preserved for extended periods of time at room temperature and are compatible with multi-omics approaches for specimen analysis. According to leading microbiome researchers and published literature, each collection method is considered optimal for use in large epidemiological studies. Moreover, the kit is comprised of various components that make stool collection easy, so as not to burden the patient and hence maximize overall compliance. Use of this kit in a study of late-stage lung cancer patients had a participation rate of 83% and baseline compliance rate of 58%.}, }
@article {pmid30929044, year = {2019}, author = {Semenec, L and Vergara, IA and Laloo, AE and Mathews, ER and Bond, PL and Franks, AE}, title = {Correction to: Enhanced Growth of Pilin-Deficient Geobacter sulfurreducens Mutants in Carbon Poor and Electron Donor Limiting Conditions.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01370-2}, pmid = {30929044}, issn = {1432-184X}, abstract = {The published version of this article contained an old version of Fig. 2.}, }
@article {pmid30926316, year = {2019}, author = {Brown, MR and Hands, CL and Coello-Garcia, T and Sani, BS and Ott, AIG and Smith, SJ and Davenport, RJ}, title = {A flow cytometry method for bacterial quantification and biomass estimates in activated sludge.}, journal = {Journal of microbiological methods}, volume = {160}, number = {}, pages = {73-83}, doi = {10.1016/j.mimet.2019.03.022}, pmid = {30926316}, issn = {1872-8359}, abstract = {Absolute bacterial quantification receives little serious attention in the literature compared to sequencing, conceivably because it is considered unimportant and facile, or because existing methods are tedious, laborious and/or biased in nature. This is particularly true in engineered systems, including activated sludge, where such information underpins their design and operation. To overcome these limitations we built upon existing work and optimised and comprehensively validated, through comparison with epifluorescence microscopy (EFM), a rapid and precise flow cytometric protocol to enumerate total bacterial numbers in activated sludge. Insights into potential biases were evaluated using appropriate statistical analyses on this comparison, which spanned four orders of magnitude, as well as comparing volatile suspended solid (VSS) concentrations. The results suggest flow cytometry (FCM) is a rapid, reproducible and economical technique for quantifying total bacterial numbers and biomass concentrations in activated sludge, despite within order of magnitude discrepancies with EFM counts, which had inherent and evidently greater errors and biases than FCM. The use of FCM for routine monitoring over both EFM and VSS should help further understanding of the microbial ecology in, and the operation of, engineered systems.}, }
@article {pmid30923872, year = {2019}, author = {Wu, RN and Meng, H and Wang, YF and Gu, JD}, title = {Functional dominance and community compositions of ammonia-oxidizing archaea in extremely acidic soils of natural forests.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {10}, pages = {4229-4240}, doi = {10.1007/s00253-019-09721-2}, pmid = {30923872}, issn = {1432-0614}, support = {31470562//National Natural Science Foundation of China/ ; }, abstract = {Extremely acidic soils of natural forests in Nanling National Nature Reserve have been previously investigated and revisited in two successive years to reveal the active ammonia oxidizers. Ammonia-oxidizing archaea (AOA) rather than ammonia-oxidizing bacteria (AOB) were found more functionally important in the extremely acidic soils of the natural forests in Nanling National Nature Reserve. The relative abundances of Nitrosotalea, Nitrososphaera sister group, and Nitrososphaera lineages recovered by ammonia monooxygenase subunit A (amoA) transcripts were reassessed and compared to AOA communities formerly detected by genomic DNA. Nitrosotalea, previously found the most abundant AOA, were the second-most-active lineage after Nitrososphaera sister group. Our field study results, therefore, propose the acidophilic AOA, Nitrosotalea, can better reside in extremely acidic soils while they may not contribute to nitrification proportionately according to their abundances or they are less functionally active. In contrast, the functional importance of Nitrososphaera sister group may be previously underestimated and the functional dominance further extends their ecological distribution as little has been reported. Nitrososphaera gargensis-like AOA, the third abundant lineage, were more active in summer. The analyses of AOA community composition and its correlation with environmental parameters support the previous observations of the potential impact of organic matter on AOA composition. Al3+, however, did not show a strong adverse correlation with the abundances of functional AOA unlike in the DNA-based study. The new data further emphasize the functional dominance of AOA in extremely acidic soils, and unveil the relative contributions of AOA lineages to nitrification and their community transitions under the environmental influences.}, }
@article {pmid30923814, year = {2019}, author = {Tiedje, JM}, title = {Editorial: Environmental aspects of antibiotic resistance.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {4}, pages = {}, doi = {10.1093/femsec/fiz019}, pmid = {30923814}, issn = {1574-6941}, }
@article {pmid30919752, year = {2019}, author = {Cabezas, A and Bovio, P and Etchebehere, C}, title = {Commercial formulation amendment transiently affects the microbial composition but not the biogas production of a full scale methanogenic UASB reactor.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/09593330.2019.1600042}, pmid = {30919752}, issn = {1479-487X}, abstract = {The treatment of dairy wastewater in methanogenic reactors cause several problems due to their high lipid content. One strategy to overcome these problems is the use of commercial formulations. Here we studied the effect of adding a commercial formulation, designed to improve fat degradation, on both the microbial community composition and reactor performance. Samples from two full-scale Up-flow Anaerobic Sludge Blanket (UASB) reactors in parallel arrangement were analysed. The commercial product was added to one of the reactors while the other was used as control. The amendment increased significantly the fat removal but an accumulation of volatile fatty acids was detected. Nevertheless, no significant differences were observed in the total Chemical Oxygen Demand (COD) removal and biogas production between reactors. A significant change in the bacterial community was not detected by 16S rRNA gene Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis probably due to the limitation of the technique. A strong change in the composition of the phylum Firmicutes was detected with 16S rRNA gene amplicon sequencing; however, it didn't persist during the whole operation period. The relative abundance of minor Operational Taxonomic Units (OTUs) with sequences related to syntrophic bacteria increased with the amendment. Although a better hydrolytic capacity was obtained when adding the commercial product, the overall process did not improve and no increase in biogas production was detected. Alternative strategies could be applied to avoid the accumulation of intermediary products and improve biogas production as intermittent addition of the commercial product or batch operation of reactors.}, }
@article {pmid30918994, year = {2019}, author = {Klima, CL and Holman, DB and Ralston, BJ and Stanford, K and Zaheer, R and Alexander, TW and McAllister, TA}, title = {Lower Respiratory Tract Microbiome and Resistome of Bovine Respiratory Disease Mortalities.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01361-3}, pmid = {30918994}, issn = {1432-184X}, support = {2015R025R//Alberta Livestock and Meat Agency/ ; 001//Growing Forward II/ ; 001//Genomics Research Initiative/ ; }, abstract = {Bovine respiratory disease (BRD) continues to be a serious health problem in beef cattle production. A multifactorial condition, BRD encompasses several types of pneumonia that are associated with multiple viral and bacterial agents. Comprehensive identification of microbes associated with BRD fatalities could enhance our understanding of the range of pathogens that contribute to the disease and identify new therapeutic targets. This study used metagenomic analysis to describe the lower respiratory tract microbiome and resistome of 15 feedlot cattle BRD and 3 non-BRD mortalities along with any affiliated integrative and conjugative elements (ICEs). Known bacterial pathogens associated with BRD, including Histophilus somni, Mannheimia haemolytica, and Mycoplasma bovis, were relatively abundant (> 5%) in most, but not all samples. Other relatively abundant genera (> 1%) included Acinetobacter, Bacillus, Bacteroides, Clostridium, Enterococcus, and Pseudomonas. Antimicrobial resistance genes (ARGs) comprised up to 0.5% of sequences and many of these genes were associated with ICEs previously described within the Pasteurellaceae family. A total of 20 putative ICEs were detected among 16 samples. These results document the wide diversity of microorganisms in the lower respiratory tract of cattle that have succumbed to BRD. The data also strongly suggest that antimicrobial-resistant Pasteurellaceae strains are prevalent in BRD cases in Alberta and that the resistance observed is associated with ICEs. The presence of ICEs harboring a wide array of ARGs holds significant consequence for the effectiveness of drug therapies for the control of BRD in beef cattle.}, }
@article {pmid30915518, year = {2019}, author = {Kolasa, M and Ścibior, R and Mazur, MA and Kubisz, D and Dudek, K and Kajtoch, Ł}, title = {How Hosts Taxonomy, Trophy, and Endosymbionts Shape Microbiome Diversity in Beetles.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01358-y}, pmid = {30915518}, issn = {1432-184X}, support = {DEC-2013/11/D/NZ8/00583//National Science Centre, Poland/ ; small grants for young researchers//Polish Ministry of Science and Higher Education/ ; }, abstract = {Bacterial communities play a crucial role in the biology, ecology, and evolution of multicellular organisms. In this research, the microbiome of 24 selected beetle species representing five families (Carabidae, Staphylinidae, Curculionidae, Chrysomelidae, Scarabaeidae) and three trophic guilds (carnivorous, herbivorous, detrivorous) was examined using 16S rDNA sequencing on the Illumina platform. The aim of the study was to compare diversity within and among species on various levels of organization, including evaluation of the impact of endosymbiotic bacteria. Collected data showed that beetles possess various bacterial communities and that microbiota of individuals of particular species hosts are intermixed. The most diverse microbiota were found in Carabidae and Scarabaeidae; the least diverse, in Staphylinidae. On higher organization levels, the diversity of bacteria was more dissimilar between families, while the most distinct with respect to their microbiomes were trophic guilds. Moreover, eight taxa of endosymbiotic bacteria were detected including common genera such as Wolbachia, Rickettsia, and Spiroplasma, as well as the rarely detected Cardinium, Arsenophonus, Buchnera, Sulcia, Regiella, and Serratia. There were no correlations among the abundance of the most common Wolbachia and Rickettsia; a finding that does not support the hypothesis that these bacteria occur interchangeably. The abundance of endosymbionts only weakly and negatively correlates with diversity of the whole microbiome in beetles. Overall, microbiome diversity was found to be more dependent on host phylogeny than on the abundance of endosymbionts. This is the first study in which bacteria diversity is compared between numerous species of beetles in a standardized manner.}, }
@article {pmid30915517, year = {2019}, author = {Neupane, S and Modry, D and Pafčo, B and Zurek, L}, title = {Correction to: Bacterial Community of the Digestive Tract of the European Medicinal Leech (Hirudo verbana) from the Danube River.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1091}, doi = {10.1007/s00248-019-01363-1}, pmid = {30915517}, issn = {1432-184X}, abstract = {The original published version of this article had mistakes in figure legends. Correct figure legends are presented below.}, }
@article {pmid30915050, year = {2019}, author = {Wang, W and Luo, X and Chen, Y and Ye, X and Wang, H and Cao, Z and Ran, W and Cui, Z}, title = {Succession of Composition and Function of Soil Bacterial Communities During Key Rice Growth Stages.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {421}, doi = {10.3389/fmicb.2019.00421}, pmid = {30915050}, issn = {1664-302X}, abstract = {Elucidating the succession of soil microbial communities and microbial functions at key plant growth stages is a major goal of microbial ecology research. In this study, we investigated the succession of soil bacteria during four fertilizer treatments (control, NPK, NPK + pig manure, and NPK + straw) and at three crucial rice growth stages (tillering, heading, and ripening) in paddy soil from a rice-wheat cropping system over a 10-year period. The results showed that the bacterial community and function composition of the control treatment was significantly different from that of the other treatments with NPK fertilizers, and S1 from others stages (ANOSIM, p < 0.05). The application of pig manure could reduce the effects of applying NPK fertilizers on bacterial communities in heading and ripening stages, but the effects of straw returning is not obvious. Variance partitioning analyses (VPA) suggested that pH, OM, and AK appeared to be key factors responsible for the microbial community changes observed in all the treatments or stages. The correlation results showed the bacterial families different between S1 and other stages such as Micromonosporaceae, Nocardioidaceae, Gaiellaceae, and Anaerolineaceae etc., were correlated with bacterial KEGG metabolic pathways. In addition, the topological of the soil bacterial community network with more nodes, links and higher Maximal degree at the heading stage and maintained relatively similar topological structures at the heading and ripening stages. However, the topological of the functional networks at the ripening stage were a small yet complicated co-occurring network with 209 nodes, 789 links, higher Average connectivity (avgK), and Maximal degree. These results suggest an obvious succession of soil bacteria and bacterial function at the key rice growth stages, but the topological of functional network structure of bacteria changes a little in the early and middle stages of rice, while its changes significantly in the ripening stage of rice growth.}, }
@article {pmid30914267, year = {2019}, author = {Zhang, X and Fan, L and Wu, J and Xu, H and Leung, WY and Fu, K and Wu, J and Liu, K and Man, K and Yang, X and Han, J and Ren, J and Yu, J}, title = {Macrophage p38α promotes nutritional steatohepatitis through M1 polarization.}, journal = {Journal of hepatology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jhep.2019.03.014}, pmid = {30914267}, issn = {1600-0641}, abstract = {BACKGROUND &amp; AIMS: p38 mitogen-activated protein kinases are important inflammatory factors. p38α alteration has been implicated in both human and mouse inflammatory disease models. Therefore, we aimed to characterize the cell type-specific role of p38α in non-alcoholic steatohepatitis (NASH).<br><br>METHODS: Human liver tissues were obtained from 27 patients with non-alcoholic fatty liver disease (NAFLD) and 20 control individuals. NASH was established and compared between hepatocyte-specific p38α knockout (p38αΔHep), macrophage-specific p38α knockout (p38αΔMΦ) and wild-type (p38αfl/fl) mice fed with high-fat diet (HFD), high-fat/high-cholesterol diet (HFHC), or methionine-and choline-deficient diet (MCD). p38 inhibitors were administered to HFHC-fed wild-type mice for disease treatment.<br><br>RESULTS: p38α was significantly upregulated in the liver tissues of patients with NAFLD. Compared to p38αfl/fl littermates, p38αΔHep mice developed significant nutritional steatohepatitis induced by HFD, HFHC or MCD. Meanwhile, p38αΔMΦ mice exhibited less severe steatohepatitis and insulin resistance than p38αfl/fl mice in response to a HFHC or MCD. The effect of macrophage p38α in promoting steatohepatitis was mediated by the induction of pro-inflammatory factors (CXCL2, IL-1β, CXCL10 and IL-6) secreted by M1 macrophages and associated signaling pathways. p38αΔMΦ mice exhibited M2 anti-inflammatory polarization as demonstrated by increased CD45+F4/80+CD11b+CD206+ M2 macrophages and enhanced arginase activity in liver tissues. Primary hepatocytes from p38αΔMΦ mice showed decreased steatosis and inflammatory damage. In a co-culture system, p38α deleted macrophages attenuated steatohepatitic changes in hepatocytes through decreased secretion of pro-inflammatory cytokines (TNF-α, CXCL10 and IL-6), which mediate M1 macrophage polarization in p38αΔMΦ mice. Restoration of TNF-α, CXCL10 or IL-6 induced lipid accumulation and inflammatory responses in p38αfl/fl hepatocytes co-cultured with p38αΔMΦ macrophages. Moreover, pharmacological p38 inhibitors suppressed HFHC-induced steatohepatitis.<br><br>CONCLUSIONS: Macrophage p38α promotes the progression of steatohepatitis by inducing pro-inflammatory cytokine secretion and M1 polarization. p38 inhibition protects against steatohepatitis. LAY SUMMARY: p38 mitogen-activated protein kinases are important inflammatory factors. In the present study, we demonstrated that p38α is upregulated in liver tissues of patients with non-alcoholic fatty liver diseases. Genetic deletion of p38α in macrophages led to ameliorated nutritional steatohepatitis in mice through decreased pro-inflammatory cytokine secretion and increased M2 macrophage polarization.}, }
@article {pmid30912268, year = {2019}, author = {Timmis, K and Cavicchioli, R and Garcia, JL and Nogales, B and Chavarría, M and Stein, L and McGenity, TJ and Webster, N and Singh, BK and Handelsman, J and de Lorenzo, V and Pruzzo, C and Timmis, J and Martín, JLR and Verstraete, W and Jetten, M and Danchin, A and Huang, W and Gilbert, J and Lal, R and Santos, H and Lee, SY and Sessitsch, A and Bonfante, P and Gram, L and Lin, RTP and Ron, E and Karahan, ZC and van der Meer, JR and Artunkal, S and Jahn, D and Harper, L}, title = {The urgent need for microbiology literacy in society.}, journal = {Environmental microbiology}, volume = {21}, number = {5}, pages = {1513-1528}, doi = {10.1111/1462-2920.14611}, pmid = {30912268}, issn = {1462-2920}, }
@article {pmid30911770, year = {2019}, author = {Pan, Y and Wu, Y and Li, X and Zeng, J and Lin, X}, title = {Continuing Impacts of Selective Inhibition on Bacterial and Fungal Communities in an Agricultural Soil.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01364-0}, pmid = {30911770}, issn = {1432-184X}, support = {41671266//National Natural Science Foundation of China/ ; }, abstract = {Selective inhibition (SI) has been routinely used to differentiate the contributions of bacteria and fungi to soil ecological processes. SI experiments typically measured rapid responses within hours since the addition of inhibitor, but the long-term effects of selective biocides on microbial community composition and function were largely unknown. In this study, a microcosm experiment was performed with an agricultural soil to explore the effectiveness of two bactericides (bronopol, streptomycin) and two fungicides (cycloheximide, captan), which were applied at two different concentrations (2 and 10 mg g-1). The microcosms were incubated for 6 weeks. A radiolabeled substrate, [1,2,3,4,4a,9a-14C] anthracene, was spiked to all microcosms, and the derived CO2 was monitored during the incubation. The abundance and composition of bacteria and fungi were assessed by qPCR and Miseq sequencing of ribosomal rRNA genes. It was demonstrated that only 2 mg g-1 bronopol and cycloheximide significantly changed the bacteria to fungi ratio without apparent non-target inhibition on the abundances; however, community shifts were observed in all treatments after 6 weeks incubation. The enrichment of specific taxa implicated a selection of resistant or adapted microbes by these biocides. Mineralization of anthracene was continuingly suppressed in all SI microcosms, which may result in biased estimate of bacterial and fungal contributions to pollutant degradation. These findings highlight the risks of long-term application of selective inhibition, and a preliminary assessment of biocide selection and concentration is highly recommended.}, }
@article {pmid30911147, year = {2019}, author = {Guo, X and Zhou, X and Hale, L and Yuan, M and Ning, D and Feng, J and Shi, Z and Li, Z and Feng, B and Gao, Q and Wu, L and Shi, W and Zhou, A and Fu, Y and Wu, L and He, Z and Van Nostrand, JD and Qiu, G and Liu, X and Luo, Y and Tiedje, JM and Yang, Y and Zhou, J}, title = {Climate warming accelerates temporal scaling of grassland soil microbial biodiversity.}, journal = {Nature ecology &amp; evolution}, volume = {3}, number = {4}, pages = {612-619}, doi = {10.1038/s41559-019-0848-8}, pmid = {30911147}, issn = {2397-334X}, abstract = {Determining the temporal scaling of biodiversity, typically described as species-time relationships (STRs), in the face of global climate change is a central issue in ecology because it is fundamental to biodiversity preservation and ecosystem management. However, whether and how climate change affects microbial STRs remains unclear, mainly due to the scarcity of long-term experimental data. Here, we examine the STRs and phylogenetic-time relationships (PTRs) of soil bacteria and fungi in a long-term multifactorial global change experiment with warming (+3 °C), half precipitation (-50%), double precipitation (+100%) and clipping (annual plant biomass removal). Soil bacteria and fungi all exhibited strong STRs and PTRs across the 12 experimental conditions. Strikingly, warming accelerated the bacterial and fungal STR and PTR exponents (that is, the w values), yielding significantly (P < 0.001) higher temporal scaling rates. While the STRs and PTRs were significantly shifted by altered precipitation, clipping and their combinations, warming played the predominant role. In addition, comparison with the previous literature revealed that soil bacteria and fungi had considerably higher overall temporal scaling rates (w = 0.39-0.64) than those of plants and animals (w = 0.21-0.38). Our results on warming-enhanced temporal scaling of microbial biodiversity suggest that the strategies of soil biodiversity preservation and ecosystem management may need to be adjusted in a warmer world.}, }
@article {pmid30910952, year = {2019}, author = {Penn, JL and Weber, T and Chang, BX and Deutsch, C}, title = {Microbial ecosystem dynamics drive fluctuating nitrogen loss in marine anoxic zones.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {15}, pages = {7220-7225}, doi = {10.1073/pnas.1818014116}, pmid = {30910952}, issn = {1091-6490}, mesh = {Ammonia/metabolism ; Aquatic Organisms/*physiology ; Bacteria, Anaerobic/*physiology ; *Climate ; Denitrification/physiology ; *Ecosystem ; Microbial Consortia/*physiology ; Nitrogen/*metabolism ; Oxygen/metabolism ; }, abstract = {The dynamics of nitrogen (N) loss in the ocean's oxygen-deficient zones (ODZs) are thought to be driven by climate impacts on ocean circulation and biological productivity. Here we analyze a data-constrained model of the microbial ecosystem in an ODZ and find that species interactions drive fluctuations in local- and regional-scale rates of N loss, even in the absence of climate variability. By consuming O2 to nanomolar levels, aerobic nitrifying microbes cede their competitive advantage for scarce forms of N to anaerobic denitrifying bacteria. Because anaerobes cannot sustain their own low-O2 niche, the physical O2 supply restores competitive advantage to aerobic populations, resetting the cycle. The resulting ecosystem oscillations induce a unique geochemical signature within the ODZ-short-lived spikes of ammonium that are found in measured profiles. The microbial ecosystem dynamics also give rise to variable ratios of anammox to heterotrophic denitrification, providing a mechanism for the unexplained variability of these pathways observed in the ocean.}, }
@article {pmid30904989, year = {2019}, author = {Yoo, K and Han, I and Ko, KS and Lee, TK and Yoo, H and Khan, MI and Tiedje, JM and Park, J}, title = {Bacillus-Dominant Airborne Bacterial Communities Identified During Asian Dust Events.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01348-0}, pmid = {30904989}, issn = {1432-184X}, support = {2018R1A6A1A08025348//National Research Foundation of Korea/ ; }, abstract = {Asian dust (AD) events have received significant attention due to their adverse effects on ecosystems and human health. However, detailed information about airborne pathogens associated with AD events is limited. This study monitored airborne bacterial communities and identified AD-specific bacteria and the potential hazards associated with these bacteria during AD events. Over a 33-month period, 40 air samples were collected under normal atmospheric conditions (non-AD events; n = 34) and during AD events (n = 6). The airborne bacterial communities in the air samples collected during non-AD events (non-AD sample) and AD events (AD sample) were evaluated using both culture-dependent and culture-independent methods. The bacterial diversity increased significantly, along with the 16S rRNA gene copy number, in AD samples (p < 0.05) and was positively correlated with PM10 concentration. High throughput sequencing of the 16S rRNA gene revealed that the relative abundance of the phylum Firmicutes increased substantially in AD samples (44.3 ± 5.0%) compared with non-AD samples (27.8 ± 4.3%). Within the phylum Firmicutes, AD samples included a greater abundance of Bacillus species (almost 23.8%) than non-AD samples (almost 13.3%). Both culture-dependent and culture-independent methods detected common predominant species closely related to Bacillus cereus during AD events. Subsequent multilocus sequence typing (MLST) and enterotoxin gene assays confirmed the presence of virulence factors in B. cereus isolates from AD samples. Furthermore, the abundance of bceT, encoding enterotoxin in B. cereus, was significantly higher in AD samples (p < 0.05). The systematic characterization of airborne bacterial communities in AD samples in this study suggests that B. cereus pose risks to public health.}, }
@article {pmid30904709, year = {2019}, author = {Vandekerckhove, TGL and Kerckhof, FM and De Mulder, C and Vlaeminck, SE and Boon, N}, title = {Determining stoichiometry and kinetics of two thermophilic nitrifying communities as a crucial step in the development of thermophilic nitrogen removal.}, journal = {Water research}, volume = {156}, number = {}, pages = {34-45}, doi = {10.1016/j.watres.2019.03.008}, pmid = {30904709}, issn = {1879-2448}, abstract = {Nitrification and denitrification, the key biological processes for thermophilic nitrogen removal, have separately been established in bioreactors at 50 °C. A well-characterized set of kinetic parameters is essential to integrate these processes while safeguarding the autotrophs performing nitrification. Knowledge on thermophilic nitrifying kinetics is restricted to isolated or highly enriched batch cultures, which do not represent bioreactor conditions. This study characterized the stoichiometry and kinetics of two thermophilic (50 °C) nitrifying communities. The most abundant ammonia oxidizing archaea (AOA) were related to the Nitrososphaera genus, clustering relatively far from known species Nitrososphaera gargensis (95.5% 16S rRNA gene sequence identity). The most abundant nitrite oxidizing bacteria (NOB) were related to Nitrospira calida (97% 16S rRNA gene sequence identity). The nitrification biomass yield was 0.20-0.24 g VSS g-1 N, resulting mainly from a high AOA yield (0.16-0.20 g VSS g-1 N), which was reflected in a high AOA abundance in the community (57-76%) compared to NOB (5-11%). Batch-wise determination of decay rates (AOA: 0.23-0.29 d-1; NOB: 0.32-0.43 d-1) rendered an overestimation compared to in situ estimations of overall decay rate (0.026-0.078 d-1). Possibly, the inactivation rate rather than the actual decay rate was determined in batch experiments. Maximum growth rates of AOA and NOB were 0.12-0.15 d-1 and 0.13-0.33 d-1 respectively. NOB were susceptible to nitrite, opening up opportunities for shortcut nitrogen removal. However, NOB had a similar growth rate and oxygen affinity (0.15-0.55 mg O2 L-1) as AOA and were resilient towards free ammonia (IC50 > 16 mg NH3-N L-1). This might complicate NOB outselection using common practices to establish shortcut nitrogen removal (SRT control; aeration control; free ammonia shocks). Overall, the obtained insights can assist in integrating thermophilic conversions and facilitate single-sludge nitrification/denitrification.}, }
@article {pmid30904186, year = {2019}, author = {Delzenne, NM and Olivares, M and Neyrinck, AM and Beaumont, M and Kjølbæk, L and Larsen, TM and Benítez-Páez, A and Romaní-Pérez, M and Garcia-Campayo, V and Bosscher, D and Sanz, Y and van der Kamp, JW}, title = {Nutritional interest of dietary fiber and prebiotics in obesity: Lessons from the MyNewGut consortium.}, journal = {Clinical nutrition (Edinburgh, Scotland)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.clnu.2019.03.002}, pmid = {30904186}, issn = {1532-1983}, abstract = {The aim of EU project MyNewGut is to contribute to future public health-related recommendations supported by new insight in gut microbiome and nutrition-host relationship. In this Opinion Paper, we first revisit the concept of dietary fiber, taking into account their interaction with the gut microbiota. This paper also summarizes the main effects of dietary fibers with prebiotic properties in intervention studies in humans, with a particular emphasis on the effects of arabinoxylans and arabinoxylo-oligosaccharides on metabolic alterations associated with obesity. Based on the existing state of the art and future development, we elaborate the steps required to propose dietary guidelines related to dietary fibers, taking into account their interaction with the gut microbiota.}, }
@article {pmid30903203, year = {2019}, author = {Hu, J and Liu, S and Yang, W and He, Z and Wang, J and Liu, H and Zheng, P and Xi, C and Ma, F and Hu, B}, title = {Ecological Success of the Nitrosopumilus and Nitrosospira Clusters in the Intertidal Zone.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01359-x}, pmid = {30903203}, issn = {1432-184X}, support = {No.41773074//National Natural Science Foundation of China/ ; No. 31828001//National Natural Science Foundation of China/ ; No.41641031//National Natural Science Foundation of China/ ; No. QAK201714//Open Project of State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology/ ; }, abstract = {The intertidal zone is an important buffer and a nitrogen sink between land and sea. Ammonia oxidation is the rate-limiting step of nitrification, conducted by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). However, it remains a debatable issue regarding dominant ammonia oxidizers in this region, and environmental factors driving their spatiotemporal niche differentiation have yet to be identified. In this study, intertidal and subtidal zones of Zhoushan Islands were selected for seasonal sampling. Ammonia-oxidizing activity, quantitative PCR, and 454 high-throughput sequencing were performed to study the nitrification potential, abundance, and community structure of ammonia-oxidizing archaea and bacteria. AOA and AOB amoA abundance (107-108amoA gene copies/g dry weight sediment) varied spatiotemporally independently of environmental factors. AOA surpassed AOB in most samples, driven by sediment temperature, moisture, and total nitrogen. The diversity of both AOA and AOB differed spatiotemporally. The Nitrosopumilus and Nitrosospira clusters accounted for an absolutely dominant percentage of AOA (> 99%) and AOB (> 99%) respectively, indicating a negligible contribution of other clusters to ammonia oxidation. However, there was no significant correlation between nitrification potential and the abundance of AOA or AOB. Overall, the present study showed that AOA dominated over AOB spatiotemporally in the intertidal zone of Zhoushan Islands due to fluctuations in environmental factors, and the Nitrosopumilus and Nitrosospira clusters ecologically succeeded in the intertidal zone of Zhoushan Islands.}, }
@article {pmid30903202, year = {2019}, author = {Borg Dahl, M and Brejnrod, AD and Russel, J and Sørensen, SJ and Schnittler, M}, title = {Different Degrees of Niche Differentiation for Bacteria, Fungi, and Myxomycetes Within an Elevational Transect in the German Alps.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01347-1}, pmid = {30903202}, issn = {1432-184X}, support = {RTG2010//Deutsche Forschungsgemeinschaft/ ; }, abstract = {We used direct DNA amplification from soil extracts to analyze microbial communities from an elevational transect in the German Alps by parallel metabarcoding of bacteria (16S rRNA), fungi (ITS2), and myxomycetes (18S rRNA). For the three microbial groups, 5710, 6133, and 261 operational taxonomic units (OTU) were found. For the latter group, we can relate OTUs to barcodes from fruit bodies sampled over a 4-year period. The alpha diversity of myxomycetes was positively correlated with that of bacteria. Vegetation type was found to be the main explanatory parameter for the community composition of all three groups and a substantial species turnover with elevation was observed. Bacteria and fungi display similar community responses, driven by symbiont species and plant substrate quality. Myxamoebae show a more patchy distribution, though still clearly stratified between taxa, which seems to be a response to both structural properties of the habitat and interaction with specific bacterial and fungal taxa. Finally, we report a high number of myxomycete OTUs not represented in a reference database from fructifications, which might represent novel species.}, }
@article {pmid30901846, year = {2019}, author = {Horniblow, RD and Mistry, P and Quraishi, MN and Beggs, AD and Van de Wiele, T and Iqbal, TH and Tselepis, C}, title = {The Safety and Tolerability of a Potential Alginate-Based Iron Chelator; Results of A Healthy Participant Study.}, journal = {Nutrients}, volume = {11}, number = {3}, pages = {}, doi = {10.3390/nu11030674}, pmid = {30901846}, issn = {2072-6643}, abstract = {Evidence supporting the ferro-toxic nature of iron in the progression of inflammatory bowel disease (IBD) is becoming well established. A microbial dysbiosis is observed in IBD patients, and intra-luminal colonic-iron is able to support a more pathogenic community of bacteria; whether this is attributed to the development of IBD and how iron could be mediating these microbial changes is still unknown. Dietary fibres are commonly used in pre-biotic supplements to beneficially affect the host by improving the viability of bacterial communities within the colon. Alginates are a class of biopolymers considered as prebiotics due to their fibre-like composition and are able to bind metal cations, in particular, iron. Considering that iron excess is able to negatively alter the microbiome, the use of alginate as a food supplement could be useful in colonic-iron chelation. As such, this first-in-man study aimed to assess whether the use of alginate as a dietary iron chelator was both safe and well tolerated. In addition, the impact of alginate on the microbiome and iron levels was assessed by using an intestinal model SHIME (Simulation of the Human Intestinal Microbial Ecosystem). Alginate was supplemented into the diets (3 g/day) of healthy volunteers (n = 17) for 28 days. Results from this study suggest that daily ingestion of 3 g alginate was well tolerated with very minor side effects. There were no detrimental changes in a variety of haematological parameters or the intestinal microbiome. The bacterial communities within the SHIME model were also not influenced by iron and or alginate; it is possible that alginate may be susceptible to bacterial or enzymatic degradation within the gastro-intestinal tract.}, }
@article {pmid30900038, year = {2019}, author = {Procópio, L and Pádula, M and van Elsas, JD and Seldin, L}, title = {Oxidative damage induced by H2O2 reveals SOS adaptive transcriptional response of Dietzia cinnamea strain P4.}, journal = {World journal of microbiology &amp; biotechnology}, volume = {35}, number = {4}, pages = {53}, doi = {10.1007/s11274-019-2628-7}, pmid = {30900038}, issn = {1573-0972}, mesh = {Actinomycetales/*drug effects/enzymology/genetics/*metabolism ; Bacterial Proteins/genetics ; Catalase/classification/genetics ; DNA Damage/drug effects ; DNA Helicases/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial ; Glutathione/genetics ; Hydrogen Peroxide/*adverse effects ; Kinetics ; *Oxidative Stress ; Peroxidases/genetics ; Peroxiredoxins/genetics ; Phylogeny ; RNA, Messenger/metabolism ; Rec A Recombinases/genetics ; SOS Response (Genetics)/genetics/*physiology ; Sequence Analysis ; Serine Endopeptidases/genetics ; Superoxide Dismutase/genetics ; Thioredoxins/genetics ; Time Factors ; Up-Regulation/drug effects ; }, abstract = {The oxidative stress response of the highly resistant actinomycete Dietzia cinnamea P4 after treatment with hydrogen peroxide (H2O2) was assessed in order to depict the possible mechanisms underlying its intrinsic high resistance to DNA damaging agents. We used transcriptional profiling to monitor the magnitude and kinetics of changes in the mRNA levels after exposure to different concentrations of H2O2 at 10 min and 1 h following the addition of the stressor. Catalase and superoxide dismutase genes were induced in different ways, according to the condition applied. Moreover, alkyl hydroperoxide reductase ahpCF, thiol peroxidase, thioredoxin and glutathione genes were upregulated in the presence of H2O2. Expression of peroxidase genes was not detected during the experiment. Overall results point to an actinomycete strain endowed with a set of enzymatic defenses against oxidative stress and with the main genes belonging to a functional SOS system (lexA, recA, uvrD), including suppression of lexA repressor, concomitantly to recA and uvrD gene upregulation upon H2O2 challenge.}, }
@article {pmid30899980, year = {2019}, author = {Jabiol, J and Lecerf, A and Lamothe, S and Gessner, MO and Chauvet, E}, title = {Litter Quality Modulates Effects of Dissolved Nitrogen on Leaf Decomposition by Stream Microbial Communities.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {959-966}, doi = {10.1007/s00248-019-01353-3}, pmid = {30899980}, issn = {1432-184X}, support = {ANR-14-CE01-0009-01//Agence Nationale de la Recherche/ ; }, mesh = {Fungi/*physiology ; *Microbiota ; Nitrogen/*metabolism ; Plant Leaves/*microbiology ; Rivers/*microbiology ; }, abstract = {Rates of leaf litter decomposition in streams are strongly influenced both by inorganic nutrients dissolved in stream water and by litter traits such as lignin, nitrogen (N) and phosphorus (P) concentrations. As a result, decomposition rates of different leaf species can show contrasting responses to stream nutrient enrichment resulting from human activities. It is unclear, however, whether the root cause of such discrepancies in field observations is the interspecific variation in either litter nutrient or litter lignin concentrations. To address this question, we conducted a controlled laboratory experiment with a known fungal community to determine decomposition rates of 38 leaf species exhibiting contrasting litter traits (N, P and lignin concentrations), which were exposed to 8 levels of dissolved N concentrations representative of field conditions across European streams (0.07 to 8.96 mg N L-1). The effect of N enrichment on decomposition rate was modelled using Monod kinetics to quantify N effects across litter species. Lignin concentration was the most important litter trait determining decomposition rates and their response to N enrichment. In particular, increasing dissolved N supply from 0.1 to 3.0 mg N L-1 accelerated the decomposition of lignin-poor litter (e.g. < 10% of lignin, 2.9× increase ± 1.4 SD, n = 14) more strongly than that of litter rich in lignin (e.g. > 15% of lignin, 1.4× increase ± 0.2 SD, n = 9). Litter nutrient concentrations were less important, with a slight positive effect of P on decomposition rates and no effect of litter N. These results indicate that shifts in riparian vegetation towards species characterized by high litter lignin concentrations could alleviate the stimulation of C turnover by stream nutrient enrichment.}, }
@article {pmid30895363, year = {2019}, author = {Hýsek, J and Vavera, R and Růžek, P}, title = {Cultivation Intensity in Combination with Other Ecological Factors as Limiting Ones for the Abundance of Phytopathogenic Fungi on Wheat.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01337-3}, pmid = {30895363}, issn = {1432-184X}, support = {MZe-RO0418//Ministry of Agriculture/ ; }, abstract = {In field and laboratory experiments during 2014-2017, we investigated the influence of lower and higher cultivation intensity of wheat and ecological factors (weather-temperature and rainfalls, year) on the occurrence of phytopathogenic fungi on the leaves of winter wheat. The prevailing fungi in those years were Mycosphaerella graminicola (Fuckel) J. Schrott and Pyrenophora tritici-repentis (Died.) Drechsler. Using cluster analysis, we statistically evaluated interrelationships of known factors on the abundance of the fungi on leaf surfaces. Our results showed strongest correlation with Mycosphaerella graminicola and Pyrenophora tritici-repentis abundance to be with lower cultivation intensity and year done by the temperature and the rainfalls. The two pathogens-Puccinia tritici Oerst and Hymenula cerealis Ellis &amp; Everh. occurred only very sparsely in some years and had little positive or negative correlation with named factors. The semi-early and semi-late winter wheat varieties Matchball, Annie, Fakir, and Tobak were used for our experiments. Higher cultivation intensity had protective effect against leaf phytopathogenic fungi.}, }
@article {pmid30894691, year = {2019}, author = {Fernando, EY and McIlroy, SJ and Nierychlo, M and Herbst, FA and Petriglieri, F and Schmid, MC and Wagner, M and Nielsen, JL and Nielsen, PH}, title = {Resolving the individual contribution of key microbial populations to enhanced biological phosphorus removal with Raman-FISH.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0399-7}, pmid = {30894691}, issn = {1751-7370}, abstract = {Enhanced biological phosphorus removal (EBPR) is a globally important biotechnological process and relies on the massive accumulation of phosphate within special microorganisms. Candidatus Accumulibacter conform to the classical physiology model for polyphosphate accumulating organisms and are widely believed to be the most important player for the process in full-scale EBPR systems. However, it was impossible till now to quantify the contribution of specific microbial clades to EBPR. In this study, we have developed a new tool to directly link the identity of microbial cells to the absolute quantification of intracellular poly-P and other polymers under in situ conditions, and applied it to eight full-scale EBPR plants. Besides Ca. Accumulibacter, members of the genus Tetrasphaera were found to be important microbes for P accumulation, and in six plants they were the most important. As these Tetrasphaera cells did not exhibit the classical phenotype of poly-P accumulating microbes, our entire understanding of the microbiology of the EBPR process has to be revised. Furthermore, our new single-cell approach can now also be applied to quantify storage polymer dynamics in individual populations in situ in other ecosystems and might become a valuable tool for many environmental microbiologists.}, }
@article {pmid30894042, year = {2019}, author = {Bor, B and Bedree, JK and Shi, W and McLean, JS and He, X}, title = {Saccharibacteria (TM7) in the Human Oral Microbiome.}, journal = {Journal of dental research}, volume = {98}, number = {5}, pages = {500-509}, doi = {10.1177/0022034519831671}, pmid = {30894042}, issn = {1544-0591}, abstract = {Bacteria from the Saccharibacteria phylum (formerly known as TM7) are ubiquitous members of the human oral microbiome and are part of the Candidate Phyla Radiation. Recent studies have revealed remarkable 16S rRNA diversity in environmental and mammalian host-associated members across this phylum, and their association with oral mucosal infectious diseases has been reported. However, due to their recalcitrance to conventional cultivation, TM7's physiology, lifestyle, and role in health and diseases remain elusive. The recent cultivation and characterization of Nanosynbacter lyticus type strain TM7x (HMT_952)-the first Saccharibacteria strain coisolated as an ultrasmall obligate parasite with its bacterial host from the human oral cavity-provide a rare glimpse into the novel symbiotic lifestyle of these enigmatic human-associated bacteria. TM7x is unique among all bacteria: it has an ultrasmall size and lives on the surface of its host bacterium. With a highly reduced genome, it lacks the ability to synthesize any of its own amino acids, vitamins, or cell wall precursors and must parasitize other oral bacteria. TM7x displays a highly dynamic interaction with its bacterial hosts, as reflected by the reciprocal morphologic and physiologic changes in both partners. Furthermore, depending on environmental conditions, TM7x can exhibit virulent killing of its host bacterium. Thus, Saccharibacteria potentially affect oral microbial ecology by modulating the oral microbiome structure hierarchy and functionality through affecting the bacterial host's physiology, inhibiting the host's growth dynamics, or affecting the relative abundance of the host via direct killing. At this time, several other uncharacterized members of this phylum have been detected in various human body sites at high prevalence. In the oral cavity alone, at least 6 distinct groups vary widely in relative abundance across anatomic sites. Here, we review the current knowledge on the diversity and unique biology of this recently uncovered group of ultrasmall bacteria.}, }
@article {pmid30891612, year = {2019}, author = {Cockerham, S and Lee, B and Orben, RA and Suryan, RM and Torres, LG and Warzybok, P and Bradley, R and Jahncke, J and Young, HS and Ouverney, C and Shaffer, SA}, title = {Microbial Ecology of the Western Gull (Larus occidentalis).}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01352-4}, pmid = {30891612}, issn = {1432-184X}, abstract = {Avian species host diverse communities of microorganisms which have important roles in the life of birds, including increased metabolism, protection from disease, and immune system development. Along with high human populations and a diversity of human uses of coastal zones, anthropogenic food sources are becoming increasingly available to some species, including gulls. Anthropogenic associations increase the likelihood of encountering foreign or pathogenic bacteria. Diseases in birds caused by bacteria are a substantial source of avian mortality; therefore, it is essential to characterize the microbiome of seabirds. Here, we determined both core and environmentally derived microbial communities of breeding western gulls (Larus occidentalis) from six colonies in California and Oregon. Using DNA extracted from bacterial swabs of the bill, cloaca, and feet of gulls, 16S rRNA gene sequencing was performed targeting the V4 region. We identified a total of 8542 operational taxonomic units (OTUs) from 75 gulls. Sixty-eight OTUs were identified in gulls from all six colonies with the greatest representation from phyla's of Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. Overall, microbial richness based on Chao's Abundance-based Coverage Estimator (ACE) index was similar for all colonies (mean = 2347 OTUs) with the smallest coastal colonies having the highest richness (mean = 2626 OTUs) and the largest colonies, located farther off-shore, having the lowest (mean = 2068 OTUs). This survey represents the most in-depth assessment to date of microbes associated with western gulls, and the first study to identify both species-specific and environmentally derived bacteria across multiple populations.}, }
@article {pmid30886359, year = {2019}, author = {Lee, KS and Palatinszky, M and Pereira, FC and Nguyen, J and Fernandez, VI and Mueller, AJ and Menolascina, F and Daims, H and Berry, D and Wagner, M and Stocker, R}, title = {An automated Raman-based platform for the sorting of live cells by functional properties.}, journal = {Nature microbiology}, volume = {4}, number = {6}, pages = {1035-1048}, doi = {10.1038/s41564-019-0394-9}, pmid = {30886359}, issn = {2058-5276}, abstract = {Stable-isotope probing is widely used to study the function of microbial taxa in their natural environment, but sorting of isotopically labelled microbial cells from complex samples for subsequent genomic analysis or cultivation is still in its early infancy. Here, we introduce an optofluidic platform for automated sorting of stable-isotope-probing-labelled microbial cells, combining microfluidics, optical tweezing and Raman microspectroscopy, which yields live cells suitable for subsequent single-cell genomics, mini-metagenomics or cultivation. We describe the design and optimization of this Raman-activated cell-sorting approach, illustrate its operation with four model bacteria (two intestinal, one soil and one marine) and demonstrate its high sorting accuracy (98.3 ± 1.7%), throughput (200-500 cells h-1; 3.3-8.3 cells min-1) and compatibility with cultivation. Application of this sorting approach for the metagenomic characterization of bacteria involved in mucin degradation in the mouse colon revealed a diverse consortium of bacteria, including several members of the underexplored family Muribaculaceae, highlighting both the complexity of this niche and the potential of Raman-activated cell sorting for identifying key players in targeted processes.}, }
@article {pmid30884680, year = {2019}, author = {Hamdouche, Y and Meile, JC and Lebrun, M and Guehi, T and Boulanger, R and Teyssier, C and Montet, D}, title = {Impact of turning, pod storage and fermentation time on microbial ecology and volatile composition of cocoa beans.}, journal = {Food research international (Ottawa, Ont.)}, volume = {119}, number = {}, pages = {477-491}, doi = {10.1016/j.foodres.2019.01.001}, pmid = {30884680}, issn = {1873-7145}, abstract = {Cocoa quality depends on several parameters, such as cocoa variety, environmental growth conditions, cultivation technique, and post-harvest treatments applied to coca beans. In this work, we studied the impact of cocoa post-harvest processing on both microbial communities structure and volatile composition. Cocoa beans samples were fermented in wooden boxes in Ivory Coast at different time intervals with turning and without turning, and derived from pods stored for two different duration times. Cocoa beans were analyzed using a molecular fingerprinting method (PCR-DGGE) in order to detect variations in microbial communities' structure; this global analysis was coupled to SPME-GC-MS for assessing cocoa volatile profiles. The results showed that the main parameter that influenced microbial communities structure was fermentation time, followed by turning, whereas, pods storage duration had a minor impact. Similar results were obtained for aromatic profile, except for pods storage duration that significantly affected volatile compound production. Global statistical analysis using Canonical Correspondence Analysis (CCA), showed the relationship between microbial communities and volatile composition. Furthermore, this study allowed the identification of discriminating microbial and chemical markers of cocoa post-harvest processing.}, }
@article {pmid30881924, year = {2019}, author = {Tribble, GD and Angelov, N and Weltman, R and Wang, BY and Eswaran, SV and Gay, IC and Parthasarathy, K and Dao, DV and Richardson, KN and Ismail, NM and Sharina, IG and Hyde, ER and Ajami, NJ and Petrosino, JF and Bryan, NS}, title = {Frequency of Tongue Cleaning Impacts the Human Tongue Microbiome Composition and Enterosalivary Circulation of Nitrate.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {39}, doi = {10.3389/fcimb.2019.00039}, pmid = {30881924}, issn = {2235-2988}, abstract = {The oral microbiome has the potential to provide an important symbiotic function in human blood pressure physiology by contributing to the generation of nitric oxide (NO), an essential cardiovascular signaling molecule. NO is produced by the human body via conversion of arginine to NO by endogenous nitric oxide synthase (eNOS) but eNOS activity varies by subject. Oral microbial communities are proposed to supplement host NO production by reducing dietary nitrate to nitrite via bacterial nitrate reductases. Unreduced dietary nitrate is delivered to the oral cavity in saliva, a physiological process termed the enterosalivary circulation of nitrate. Previous studies demonstrated that disruption of enterosalivary circulation via use of oral antiseptics resulted in increases in systolic blood pressure. These previous studies did not include detailed information on the oral health of enrolled subjects. Using 16S rRNA gene sequencing and analysis, we determined whether introduction of chlorhexidine antiseptic mouthwash for 1 week was associated with changes in tongue bacterial communities and resting systolic blood pressure in healthy normotensive individuals with documented oral hygiene behaviors and free of oral disease. Tongue cleaning frequency was a predictor of chlorhexidine-induced changes in systolic blood pressure and tongue microbiome composition. Twice-daily chlorhexidine usage was associated with a significant increase in systolic blood pressure after 1 week of use and recovery from use resulted in an enrichment in nitrate-reducing bacteria on the tongue. Individuals with relatively high levels of bacterial nitrite reductases had lower resting systolic blood pressure. These results further support the concept of a symbiotic oral microbiome contributing to human health via the enterosalivary nitrate-nitrite-NO pathway. These data suggest that management of the tongue microbiome by regular cleaning together with adequate dietary intake of nitrate provide an opportunity for the improvement of resting systolic blood pressure.}, }
@article {pmid30877120, year = {2019}, author = {Wang, T and Tian, Z and Tunlid, A and Persson, P}, title = {Influence of Ammonium on Formation of Mineral-Associated Organic Carbon by an Ectomycorrhizal Fungus.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {10}, pages = {}, doi = {10.1128/AEM.03007-18}, pmid = {30877120}, issn = {1098-5336}, abstract = {The interactions between dissolved organic matter (DOM) and mineral particles are critical for the stabilization of soil organic matter (SOM) in terrestrial ecosystems. The processing of DOM by ectomycorrhizal fungi contributes to the formation of mineral-stabilized SOM by two contrasting pathways: the extracellular transformation of DOM (ex vivo pathway) and the secretion of mineral-surface-reactive metabolites (in vivo pathway). In this study, we examined how changes in nitrogen (N) availability affected the formation of mineral-associated carbon (C) from these two pathways. DOM was extracted from forest soils. The processing of this DOM by the ectomycorrhizal fungus Paxillus involutus was examined in laboratory-scale studies with different levels of ammonium. At low levels of ammonium (i.e., under N-limited conditions), the DOM components were slightly oxidized, and fungal C metabolites with iron-reducing activity were secreted. Ammonium amendments decreased the amount of C metabolites, and no additional oxidation of the organic matter was detected. In contrast, the hydrolytic activity and the secretion of N-containing compounds increased, particularly when high levels of ammonium were added. Under these conditions, C, but not N, limited fungal growth. Although the overall production of mineral-associated organic C was not affected by ammonium concentrations, the observed shifts in the activities of the ex vivo and in vivo pathways affected the composition of organic matter adsorbed onto the mineral particles. Such changes will affect the properties of organic matter-mineral associations and, thus, ultimately, the stabilization of SOM.IMPORTANCE Nitrogen (N) availability plays a critical role in the cycling and storage of soil organic matter (SOM). However, large uncertainties remain in predicting the net effect of N addition on soil organic carbon (C) storage due to the complex interactions between organic matter, microbial activity, and mineral particles that determine the formation of stable SOM. Here, we attempted to disentangle the effects of ammonium on these interactions in controlled microcosm experiments including the ectomycorrhizal fungus P.involutus and dissolved organic matter extracted from forest soils. Increased ammonium levels affected the fungal processing of the organic material as well as the secretion of extracellular metabolites. Although ammonium additions did not increase the net production of mineral-adsorbed C, changes in the decomposition and secretion pathways altered the composition of the adsorbed organic matter. These changes may influence the properties of the organic matter-mineral associations and, thus, the stabilization of SOM.}, }
@article {pmid30875864, year = {2019}, author = {Uritskiy, G and DiRuggiero, J}, title = {Applying Genome-Resolved Metagenomics to Deconvolute the Halophilic Microbiome.}, journal = {Genes}, volume = {10}, number = {3}, pages = {}, doi = {10.3390/genes10030220}, pmid = {30875864}, issn = {2073-4425}, support = {NNX15AP18G//National Aeronautics and Space Administration/ ; DEB1556574//National Science Foundation/ ; }, abstract = {In the past decades, the study of microbial life through shotgun metagenomic sequencing has rapidly expanded our understanding of environmental, synthetic, and clinical microbial communities. Here, we review how shotgun metagenomics has affected the field of halophilic microbial ecology, including functional potential reconstruction, virus⁻host interactions, pathway selection, strain dispersal, and novel genome discoveries. However, there still remain pitfalls and limitations from conventional metagenomic analysis being applied to halophilic microbial communities. Deconvolution of halophilic metagenomes has been difficult due to the high G + C content of these microbiomes and their high intraspecific diversity, which has made both metagenomic assembly and binning a challenge. Halophiles are also underrepresented in public genome databases, which in turn slows progress. With this in mind, this review proposes experimental and analytical strategies to overcome the challenges specific to the halophilic microbiome, from experimental designs to data acquisition and the computational analysis of metagenomic sequences. Finally, we speculate about the potential applications of other next-generation sequencing technologies in halophilic communities. RNA sequencing, long-read technologies, and chromosome conformation assays, not initially intended for microbiomes, are becoming available in the study of microbial communities. Together with recent analytical advancements, these new methods and technologies have the potential to rapidly advance the field of halophile research.}, }
@article {pmid30875367, year = {2019}, author = {Cougoul, A and Bailly, X and Vourc'h, G and Gasqui, P}, title = {Rarity of microbial species: In search of reliable associations.}, journal = {PloS one}, volume = {14}, number = {3}, pages = {e0200458}, doi = {10.1371/journal.pone.0200458}, pmid = {30875367}, issn = {1932-6203}, abstract = {The role of microbial interactions in defining the properties of microbiota is a topic of key interest in microbial ecology. Microbiota contain hundreds to thousands of operational taxonomic units (OTUs), most of them rare. This feature of community structure can lead to methodological difficulties: simulations have shown that methods for detecting pairwise associations between OTUs, which presumably reflect interactions, yield problematic results. The performance of association detection tools is impaired when there is a high proportion of zeros in OTU tables. Our goal was to understand the impact of OTU rarity on the detection of associations. We explored the utility of common statistics for testing associations; the sensitivity of alternative association measures; and the performance of network inference tools. We found that a large proportion of pairwise associations, especially negative associations, cannot be reliably tested. This constraint could hamper the identification of candidate biological agents that could be used to control rare pathogens. Identifying testable associations could serve as an objective method for filtering datasets in lieu of current empirical approaches. This trimming strategy could significantly reduce the computational time needed to infer networks and network inference quality. Different possibilities for improving the analysis of associations within microbiota are discussed.}, }
@article {pmid30874727, year = {2019}, author = {Hädrich, A and Taillefert, M and Akob, DM and Cooper, RE and Litzba, U and Wagner, FE and Nietzsche, S and Ciobota, V and Rösch, P and Popp, J and Küsel, K}, title = {Microbial Fe(II) oxidation by Sideroxydans lithotrophicus ES-1 in the presence of Schlöppnerbrunnen fen-derived humic acids.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {4}, pages = {}, doi = {10.1093/femsec/fiz034}, pmid = {30874727}, issn = {1574-6941}, abstract = {Controlled laboratory experiments were combined with field measurements to better understand the interactions between dissolved organic matter (DOM) and reduced iron in organic-rich peatlands. Addition of peat-derived humic acid extract (HA) to Sideroxydans lithotrophicus ES-1 liquid cultures led to higher cell numbers and up to 1.4 times higher Fe(II) oxidation rates compared to chemical controls. This effect was positively correlated with increasing HA concentrations. Similar Fe(III) (oxyhydr)oxide mineralogies were formed both abiotically and biotically irrespective of HA amendment, but minerals formed in the presence of ES-1 and HA were smaller. ES-1 growth with HA promoted aggregation of Fe(III) products in agarose-stabilized gradient tubes as shown by voltammetric profiling. In situ voltammetry in an acidic, iron-rich peatland revealed a gap between oxygen penetration and iron reduction that may reflect active Fe(II)-oxidizing microorganisms. The highest abundance of Fe(II) oxidizers Sideroxydans (4.9 × 107 gene copies gww-1) and Gallionella (1.5 × 107 gene copies gww-1) in the upper peat layer coincided with small-sized minerals resembling nanoparticulate ferrihydrite or goethite. Our results suggest that microbially mediated Fe(II) oxidation dominates in the presence of DOM leading to the formation of nano-sized biogenic Fe(III) (oxyhydr)oxides that might be readily bioavailable and likely important to iron and carbon cycling.}, }
@article {pmid30873129, year = {2019}, author = {Hanson, CA and Müller, AL and Loy, A and Dona, C and Appel, R and Jørgensen, BB and Hubert, CRJ}, title = {Historical Factors Associated With Past Environments Influence the Biogeography of Thermophilic Endospores in Arctic Marine Sediments.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {245}, doi = {10.3389/fmicb.2019.00245}, pmid = {30873129}, issn = {1664-302X}, abstract = {Selection by the local, contemporary environment plays a prominent role in shaping the biogeography of microbes. However, the importance of historical factors in microbial biogeography is more debatable. Historical factors include past ecological and evolutionary circumstances that may have influenced present-day microbial diversity, such as dispersal and past environmental conditions. Diverse thermophilic sulfate-reducing Desulfotomaculum are present as dormant endospores in marine sediments worldwide where temperatures are too low to support their growth. Therefore, they are dispersed to here from elsewhere, presumably a hot, anoxic habitat. While dispersal through ocean currents must influence their distribution in cold marine sediments, it is not clear whether even earlier historical factors, related to the source habitat where these organisms were once active, also have an effect. We investigated whether these historical factors may have influenced the diversity and distribution of thermophilic endospores by comparing their diversity in 10 Arctic fjord surface sediments. Although community composition varied spatially, clear biogeographic patterns were only evident at a high level of taxonomic resolution (>97% sequence similarity of the 16S rRNA gene) achieved with oligotyping. In particular, the diversity and distribution of oligotypes differed for the two most prominent OTUs (defined using a standard 97% similarity cutoff). One OTU was dominated by a single ubiquitous oligotype, while the other OTU consisted of ten more spatially localized oligotypes that decreased in compositional similarity with geographic distance. These patterns are consistent with differences in historical factors that occurred when and where the taxa were once active, prior to sporulation. Further, the influence of history on biogeographic patterns was only revealed by analyzing microdiversity within OTUs, suggesting that populations within standard OTU-level groupings do not necessarily share a common ecological and evolutionary history.}, }
@article {pmid30872712, year = {2019}, author = {Oh, S and Choi, D and Cha, CJ}, title = {Ecological processes underpinning microbial community structure during exposure to subinhibitory level of triclosan.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {4598}, doi = {10.1038/s41598-019-40936-5}, pmid = {30872712}, issn = {2045-2322}, abstract = {Ecological processes shaping the structure and diversity of microbial communities are of practical importance for managing the function and resilience of engineered biological ecosystems such as activated sludge processes. This study systematically evaluated the ecological processes acting during continuous exposure to a subinhibitory level of antimicrobial triclosan (TCS) as an environmental stressor. 16S rRNA gene-based community profiling revealed significant perturbations on the community structure and dramatic reduction (by 20-30%) in species diversity/richness compared to those under the control conditions. In addition, community profiling determined the prevalence of the deterministic processes overwhelming the ecological stochasticity. Analysis of both community composition and phenotypes in the TCS-exposed communities suggested the detailed deterministic mechanism: selection of TCS degrading (Sphingopyxis) and resistant (Pseudoxanthomonas) bacterial populations. The analysis also revealed a significant reduction of core activated sludge members, Chitinophagaceae (e.g., Ferruginibacter) and Comamonadaceae (e.g., Acidovorax), potentially affecting ecosystem functions (e.g., floc formation and nutrient removal) directly associated with system performance (i.e., wastewater treatment efficiency and effluent quality). Overall, our study provides new findings that inform the mechanisms underlying the community structure and diversity of activated sludge, which not only advances the current understanding of microbial ecology in activated sludge, but also has practical implications for the design and operation of environmental bioprocesses for treatment of antimicrobial-bearing waste streams.}, }
@article {pmid30872659, year = {2019}, author = {Johnston, J and LaPara, T and Behrens, S}, title = {Composition and Dynamics of the Activated Sludge Microbiome during Seasonal Nitrification Failure.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {4565}, doi = {10.1038/s41598-019-40872-4}, pmid = {30872659}, issn = {2045-2322}, abstract = {Wastewater treatment plants in temperate climate zones frequently undergo seasonal nitrification failure in the winter month yet maintain removal efficiency for other contaminants. We tested the hypothesis that nitrification failure can be correlated to shifts in the nitrifying microbial community. We monitored three parallel, full-scale sequencing batch reactors over the course of a year with respect to reactor performance, microbial community composition via 16S rRNA gene amplicon sequencing, and functional gene abundance using qPCR. All reactors demonstrated similar changes to their core microbiome, and only subtle variations among seasonal and transient taxa. We observed a decrease in species richness during the winter, with a slow recovery of the activated sludge community during spring. Despite the change in nitrification performance, ammonia monooxygenase gene abundances remained constant throughout the year, as did the relative sequence abundance of Nitrosomonadacae. This suggests that nitrification failure at colder temperatures might result from different reaction kinetics of nitrifying taxa, or that other organisms with strong seasonal shifts in population abundance, e.g. an uncultured lineage of Saprospiraceae, affect plant performance in the winter. This research is a comprehensive analysis of the seasonal microbial community dynamics in triplicate full-scale sequencing batch reactors and ultimately strengthens our basic understanding of the microbial ecology of activated sludge communities by revealing seasonal succession patterns of individual taxa that correlate with nutrient removal efficiency.}, }
@article {pmid30869196, year = {2019}, author = {Liu, YS and Wang, LF and Cheng, XS and Huo, YN and Ouyang, XM and Liang, LY and Lin, Y and Wu, JF and Ren, JL and Guleng, B}, title = {The pattern-recognition molecule mindin binds integrin Mac-1 to promote macrophage phagocytosis via Syk activation and NF-κB p65 translocation.}, journal = {Journal of cellular and molecular medicine}, volume = {23}, number = {5}, pages = {3402-3416}, doi = {10.1111/jcmm.14236}, pmid = {30869196}, issn = {1582-4934}, support = {81770548//National Natural Science Foundation/ ; 81770558//National Natural Science Foundation/ ; 81570496//National Natural Science Foundation/ ; 2015CB553800//973 programs/ ; 2015BAI13B07//National Clinical Research Center for Digestive Diseases, Xi'an/ ; }, abstract = {Mindin has a broad spectrum of roles in the innate immune system, including in macrophage migration, antigen phagocytosis and cytokine production. Mindin functions as a pattern-recognition molecule for microbial pathogens. However, the underlying mechanisms of mindin-mediated phagocytosis and its exact membrane receptors are not well established. Herein, we generated mindin-deficient mice using the CRISPR-Cas9 system and show that peritoneal macrophages from mindin-deficient mice were severely defective in their ability to phagocytize E coli. Phagocytosis was enhanced when E coli or fluorescent particles were pre-incubated with mindin, indicating that mindin binds directly to bacteria or non-pathogen particles and promotes phagocytosis. We defined that 131 I-labelled mindin binds with integrin Mac-1 (CD11b/CD18), the F-spondin (FS)-fragment of mindin binds with the αM -I domain of Mac-1 and that mindin serves as a novel ligand of Mac-1. Blockade of the αM -I domain of Mac-1 using either a neutralizing antibody or si-Mac-1 efficiently blocked mindin-induced phagocytosis. Furthermore, mindin activated the Syk and MAPK signalling pathways and promoted NF-κB entry into the nucleus. Our data indicate that mindin binds with the integrin Mac-1 to promote macrophage phagocytosis through Syk activation and NF-κB p65 translocation, suggesting that the mindin/Mac-1 axis plays a critical role during innate immune responses.}, }
@article {pmid30868207, year = {2019}, author = {Brown, SP and Jumpponen, A}, title = {Microbial Ecology of Snow Reveals Taxa-Specific Biogeographical Structure.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {946-958}, doi = {10.1007/s00248-019-01357-z}, pmid = {30868207}, issn = {1432-184X}, mesh = {*Bacterial Physiological Phenomena ; Colorado ; Fungi/*physiology ; Microalgae/*physiology ; Microbiota ; Scandinavian and Nordic Countries ; Snow/*microbiology ; }, abstract = {Snows that persist late into the growing season become colonized with numerous metabolically active microorganisms, yet underlying mechanisms of community assembly and dispersal remain poorly known. We investigated (Illumina MiSeq) snow-borne bacterial, fungal, and algal communities across a latitudinal gradient in Fennoscandia and inter-continental distribution between northern Europe and North America. Our data indicate that bacterial communities are ubiquitous regionally (across Fennoscandia), whereas fungal communities are regionally heterogeneous. Both fungi and bacteria are biogeographically heterogeneous inter-continentally. Snow algae, generally thought to occur in colorful algae blooms (red, green, or yellow) on the snow surface, are molecularly described here as an important component of snows even in absence of visible algal growth. This suggests that snow algae are a previously underestimated major biological component of visually uncolonized snows. In contrast to fungi and bacteria, algae exhibit no discernible inter-continental or regional community structure and exhibit little endemism. These results indicate that global and regional snow microbial communities and their distributions may be dictated by a combination of size-limited propagule dispersal potential and restrictions (bacteria and fungi) and homogenization of ecologically specialized taxa (snow algae) across the globe. These results are among the first to compare inter-continental snow microbial communities and highlight how poorly understood microbial communities in these threatened ephemeral ecosystems are.}, }
@article {pmid30867308, year = {2019}, author = {Chong, R and Shi, M and Grueber, CE and Holmes, EC and Hogg, CJ and Belov, K and Barrs, VR}, title = {Fecal Viral Diversity of Captive and Wild Tasmanian Devils Characterized Using Virion-Enriched Metagenomics and Metatranscriptomics.}, journal = {Journal of virology}, volume = {93}, number = {11}, pages = {}, doi = {10.1128/JVI.00205-19}, pmid = {30867308}, issn = {1098-5514}, abstract = {The Tasmanian devil is an endangered carnivorous marsupial threatened by devil facial tumor disease (DFTD). While research on DFTD has been extensive, little is known about viruses in devils and whether any are of potential conservation relevance for this endangered species. Using both metagenomics based on virion enrichment and sequence-independent amplification (virion-enriched metagenomics) and metatranscriptomics based on bulk RNA sequencing, we characterized and compared the fecal viromes of captive and wild devils. A total of 54 fecal samples collected from two captive and four wild populations were processed for virome characterization using both approaches. In total, 24 novel marsupial-related viruses, comprising a sapelovirus, astroviruses, rotaviruses, picobirnaviruses, parvoviruses, papillomaviruses, polyomaviruses, and a gammaherpesvirus, were identified, as well as known mammalian pathogens such as rabbit hemorrhagic disease virus 2. Captive devils showed significantly lower viral diversity than wild devils. Comparison of the two virus discovery approaches revealed substantial differences in the number and types of viruses detected, with metatranscriptomics better suited for RNA viruses and virion-enriched metagenomics largely identifying more DNA viruses. Thus, the viral communities revealed by virion-enriched metagenomics and metatranscriptomics were not interchangeable and neither approach was able to detect all viruses present. An integrated approach using both virion-enriched metagenomics and metatranscriptomics constitutes a powerful tool for obtaining a complete overview of both the taxonomic and functional profiles of viral communities within a sample.IMPORTANCE The Tasmanian devil is an iconic Australian marsupial that has suffered an 80% population decline due to a contagious cancer, devil facial tumor disease, along with other threats. Until now, viral discovery in this species has been confined to one gammaherpesvirus (dasyurid herpesvirus 2 [DaHV-2]), for which captivity was identified as a significant risk factor. Our discovery of 24 novel marsupial-associated RNA and DNA viruses, and that viral diversity is lower in captive than in wild devils, has greatly expanded our knowledge of gut-associated viruses in devils and provides important baseline information that will contribute to the conservation and captive management of this endangered species. Our results also revealed that a combination of virion-enriched metagenomics and metatranscriptomics may be a more comprehensive approach for virome characterization than either method alone. Our results thus provide a springboard for continuous improvements in the way we study complex viral communities.}, }
@article {pmid30867296, year = {2019}, author = {Verma, J and Bag, S and Saha, B and Kumar, P and Ghosh, TS and Dayal, M and Senapati, T and Mehra, S and Dey, P and Desigamani, A and Kumar, D and Rana, P and Kumar, B and Maiti, TK and Sharma, NC and Bhadra, RK and Mutreja, A and Nair, GB and Ramamurthy, T and Das, B}, title = {Genomic plasticity associated with antimicrobial resistance in Vibrio cholerae.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {13}, pages = {6226-6231}, doi = {10.1073/pnas.1900141116}, pmid = {30867296}, issn = {1091-6490}, mesh = {Anti-Bacterial Agents/pharmacology ; Cholera/*microbiology ; Conjugation, Genetic/genetics ; DNA Transposable Elements/genetics ; Diarrhea/microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Evolution, Molecular ; Feces/microbiology ; *Gene Transfer, Horizontal ; Genetic Variation ; Genome, Bacterial/*genetics ; Genomic Islands/genetics ; Humans ; Imipenem/pharmacology ; India ; Interspersed Repetitive Sequences/genetics ; Phenotype ; Plasmids/genetics ; Prophages/genetics ; Proteome ; Vibrio cholerae/drug effects/*genetics/isolation &amp; purification/pathogenicity ; Vibrio cholerae O1/genetics/isolation &amp; purification/pathogenicity ; Whole Genome Sequencing ; }, abstract = {The Bay of Bengal is known as the epicenter for seeding several devastating cholera outbreaks across the globe. Vibrio cholerae, the etiological agent of cholera, has extraordinary competency to acquire exogenous DNA by horizontal gene transfer (HGT) and adapt them into its genome for structuring metabolic processes, developing drug resistance, and colonizing the human intestine. Antimicrobial resistance (AMR) in V. cholerae has become a global concern. However, little is known about the identity of the resistance traits, source of AMR genes, acquisition process, and stability of the genetic elements linked with resistance genes in V. cholerae Here we present details of AMR profiles of 443 V. cholerae strains isolated from the stool samples of diarrheal patients from two regions of India. We sequenced the whole genome of multidrug-resistant (MDR) and extensively drug-resistant (XDR) V. cholerae to identify AMR genes and genomic elements that harbor the resistance traits. Our genomic findings were further confirmed by proteome analysis. We also engineered the genome of V. cholerae to monitor the importance of the autonomously replicating plasmid and core genome in the resistance profile. Our findings provided insights into the genomes of recent cholera isolates and identified several acquired traits including plasmids, transposons, integrative conjugative elements (ICEs), pathogenicity islands (PIs), prophages, and gene cassettes that confer fitness to the pathogen. The knowledge generated from this study would help in better understanding of V. cholerae evolution and management of cholera disease by providing clinical guidance on preferred treatment regimens.}, }
@article {pmid30861385, year = {2019}, author = {Rodriguez-Sanchez, A and Muñoz-Palazon, B and Hurtado-Martinez, M and Maza-Marquez, P and Gonzalez-Lopez, J and Vahala, R and Gonzalez-Martinez, A}, title = {Microbial ecology dynamics of a partial nitritation bioreactor with Polar Arctic Circle activated sludge operating at low temperature.}, journal = {Chemosphere}, volume = {225}, number = {}, pages = {73-82}, doi = {10.1016/j.chemosphere.2019.03.012}, pmid = {30861385}, issn = {1879-1298}, abstract = {A lab-scale partial nitritation SBR was operated at 11 °C for 300 days used for the treatment of high-ammonium wastewater, which was inoculated with activated sludge from Rovaniemi WWTP (located in Polar Arctic Circle) in order to evaluate the influence the temperature on the performance, stability and dynamics of its microbial community. The partial nitritation achieved steady-state long-term operation and granulation process was not affected despite the low temperature and high ammonia concentration. The steady conditions were reached after 60 days of operation where the granular biomass was fully-formed and the 50%-50% of ammonium-nitrite effluent was successful achieved. Inoculation with cold adapted inoculum showed to yield bigger, denser granules with faster start-up without necessity of low temperature adaptation period. Next-generation sequences techniques showed that Trichosporonaceae and Xanthomonadaceae were the dominant OTUs in the mature granules. Our study could be useful in the implementation of full-scale partial nitritation reactors in cold regions such as Nordic countries for treating wastewater with high concentration of ammonium.}, }
@article {pmid30857548, year = {2019}, author = {Kim, SJ and Kim, JG and Lee, SH and Park, SJ and Gwak, JH and Jung, MY and Chung, WH and Yang, EJ and Park, J and Jung, J and Hahn, Y and Cho, JC and Madsen, EL and Rodriguez-Valera, F and Hyun, JH and Rhee, SK}, title = {Correction to: Genomic and metatranscriptomic analyses of carbon remineralization in an Antarctic polynya.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {38}, doi = {10.1186/s40168-019-0655-0}, pmid = {30857548}, issn = {2049-2618}, abstract = {Following publication of the original article [1], the authors identified wrong citations in the maintext.}, }
@article {pmid30856427, year = {2019}, author = {Prévoteau, A and Clauwaert, P and Kerckhof, FM and Rabaey, K}, title = {Oxygen-reducing microbial cathodes monitoring toxic shocks in tap water.}, journal = {Biosensors &amp; bioelectronics}, volume = {132}, number = {}, pages = {115-121}, doi = {10.1016/j.bios.2019.02.037}, pmid = {30856427}, issn = {1873-4235}, abstract = {Electroactive biofilms (EABs) have recently attracted considerable research interest for their possible use as amperometric biosensors in environmental or bioprocess monitoring, for example for in situ detection of toxic compounds. Almost exclusively, corresponding research has focused on heterotrophic, anodic EABs. These biofilms require sufficiently high organic loads and anoxic conditions to deliver a stable baseline current. Conversely, electroautotrophic O2-reducing EABs have recently been proposed to monitor toxic shocks in oxic solutions that are poor or devoid of organic substrate. This was done in optimal media and only assessed for formaldehyde as a model toxic compound. Here we show that O2-reducing EABs can grow in unamended tap water on carbon electrodes at + 0.2 V vs. Ag/AgCl. They retained substantial electroactivity for at least eight months without adding exogenous compounds. The most represented operational taxonomic units were assigned to the phylum Gammaproteobacteria (25 ± 15%, n = 5 electrodes). Cyclic voltammograms showed a reproducible nernstian behavior for O2 reduction with a mid-wave potential at + 0.27 V and variable plateau current densities ranging from - 1 to - 22 µA cm-2 (n = 10 electrodes). The biocatalytic current was substantially impacted by the addition of either of three tested heavy metals (Hg(II), Cr(VI) or Pb(II)) or by organic pollutants (formaldehyde, 2,4-dichlorophenol, benzalkonium chloride), with limits of detection ranging from 0.5 to 10 mg L-1 (2.5-61 µmol L-1). Response times were typically around 1 min. Comparison with previous reports suggests that O2-reducing microbial cathodes may be more sensitive to toxic shocks than anodic, heterotrophic EABs.}, }
@article {pmid30855669, year = {2019}, author = {Horton, DJ and Theis, KR and Uzarski, DG and Learman, DR}, title = {Microbial community structure and microbial networks correspond to nutrient gradients within coastal wetlands of the Laurentian Great Lakes.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {4}, pages = {}, doi = {10.1093/femsec/fiz033}, pmid = {30855669}, issn = {1574-6941}, abstract = {Microbial communities within the soil of Laurentian Great Lakes coastal wetlands drive biogeochemical cycles and provide several other ecosystem services. However, there exists a lack of understanding of how microbial communities respond to nutrient gradients and human activity in these systems. This research sought to address the lack of understanding through exploration of relationships among nutrient gradients, microbial community diversity, and microbial networks. Significant differences in microbial community structure were found among coastal wetlands within the western basin of Lake Erie and all other wetlands studied (three regions within Saginaw Bay and one region in the Beaver Archipelago). These diversity differences coincided with higher nutrient levels within the Lake Erie region. Site-to-site variability also existed within the majority of the regions studied, suggesting site-scale heterogeneity may impact microbial community structure. Several subnetworks of microbial communities and individual community members were related to chemical gradients among wetland regions, revealing several candidate indicator communities and taxa that may be useful for Great Lakes coastal wetland management. This research provides an initial characterization of microbial communities among Great Lakes coastal wetlands and demonstrates that microbial communities could be negatively impacted by anthropogenic activities.}, }
@article {pmid30854582, year = {2019}, author = {Sun, W and Xiao, E and Krumins, V and Dong, Y and Li, B and Deng, J and Wang, Q and Xiao, T and Liu, J}, title = {Comparative Analyses of the Microbial Communities Inhabiting Coal Mining Waste Dump and an Adjacent Acid Mine Drainage Creek.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01335-5}, pmid = {30854582}, issn = {1432-184X}, support = {41771301//National Natural Science Foundation of China/ ; 41420104007//National Natural Science Foundation of China/ ; }, abstract = {Microbial communities inhabiting the acid mine drainage (AMD) have been extensively studied, but the microbial communities in the coal mining waste dump that may generate the AMD are still relatively under-explored. In this study, we characterized the microbial communities within these under-explored extreme habitats and compared with those in the downstream AMD creek. In addition, the interplay between the microbiota and the environmental parameters was statistically investigated. A Random Forest ensemble model indicated that pH was the most important environmental parameter influencing microbial community and diversity. Parameters associated with nitrogen cycling were also critical factors, with positive effects on microbial diversity, while S-related parameters had negative effects. The microbial community analysis also indicated that the microbial assemblage was driven by pH. Various taxa were enriched in different pH ranges: Sulfobacillus was the indicator genus in samples with pH < 3 while Acidobacteriaceae-affiliated bacteria prevailed in samples with 3 < pH < 3.5. The detection of some lineages that are seldom reported in mining areas suggested the coal mining dumps may be a reservoir of phylogenetic novelty. For example, potential nitrogen fixers, autotrophs, and heterotrophs may form diverse communities that actively self-perpetuate pyrite dissolution and acidic waste generation, suggesting unique ecological strategies adopted by these innate microorganisms. In addition, co-occurrence network analyses suggest that members of Acidimicrobiales play important roles in interactions with other taxa, especially Fe- and S-oxidizing bacteria such as Sulfobacillus spp.}, }
@article {pmid30853950, year = {2019}, author = {Mareš, J and Strunecký, O and Bučinská, L and Wiedermannová, J}, title = {Evolutionary Patterns of Thylakoid Architecture in Cyanobacteria.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {277}, doi = {10.3389/fmicb.2019.00277}, pmid = {30853950}, issn = {1664-302X}, abstract = {While photosynthetic processes have become increasingly understood in cyanobacterial model strains, differences in the spatial distribution of thylakoid membranes among various lineages have been largely unexplored. Cyanobacterial cells exhibit an intriguing diversity in thylakoid arrangements, ranging from simple parietal to radial, coiled, parallel, and special types. Although metabolic background of their variability remains unknown, it has been suggested that thylakoid patterns are stable in certain phylogenetic clades. For decades, thylakoid arrangements have been used in cyanobacterial classification as one of the crucial characters for definition of taxa. The last comprehensive study addressing their evolutionary history in cyanobacteria was published 15 years ago. Since then both DNA sequence and electron microscopy data have grown rapidly. In the current study, we map ultrastructural data of >200 strains onto the SSU rRNA gene tree, and the resulting phylogeny is compared to a phylogenomic tree. Changes in thylakoid architecture in general follow the phylogeny of housekeeping loci. Parietal arrangement is resolved as the original thylakoid organization, evolving into complex arrangement in the most derived group of heterocytous cyanobacteria. Cyanobacteria occupying intermediate phylogenetic positions (greater filamentous, coccoid, and baeocytous types) exhibit fascicular, radial, and parallel arrangements, partly tracing the reconstructed course of phylogenetic branching. Contrary to previous studies, taxonomic value of thylakoid morphology seems very limited. Only special cases such as thylakoid absence or the parallel arrangement could be used as taxonomically informative apomorphies. The phylogenetic trees provide evidence of both paraphyly and reversion from more derived architectures in the simple parietal thylakoid pattern. Repeated convergent evolution is suggested for the radial and fascicular architectures. Moreover, thylakoid arrangement is constrained by cell size, excluding the occurrence of complex architectures in cyanobacteria smaller than 2 μm in width. It may further be dependent on unknown (eco)physiological factors as suggested by recurrence of the radial type in unrelated but morphologically similar cyanobacteria, and occurrence of special features throughout the phylogeny. No straightforward phylogenetic congruences have been found between proteins involved in photosynthesis and thylakoid formation, and the thylakoid patterns. Remarkably, several postulated thylakoid biogenesis factors are partly or completely missing in cyanobacteria, challenging their proposed essential roles.}, }
@article {pmid30853948, year = {2019}, author = {Coclet, C and Garnier, C and Durrieu, G and Omanović, D and D'Onofrio, S and Le Poupon, C and Mullot, JU and Briand, JF and Misson, B}, title = {Changes in Bacterioplankton Communities Resulting From Direct and Indirect Interactions With Trace Metal Gradients in an Urbanized Marine Coastal Area.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {257}, doi = {10.3389/fmicb.2019.00257}, pmid = {30853948}, issn = {1664-302X}, abstract = {Unraveling the relative importance of both environmental conditions and ecological processes regulating bacterioplankton communities is a central goal in microbial ecology. Marine coastal environments are among the most urbanized areas and as a consequence experience environmental pressures. The highly anthropized Toulon Bay (France) was considered as a model system to investigate shifts in bacterioplankton communities along natural and anthropogenic physicochemical gradients during a 1-month survey. In depth geochemical characterization mainly revealed strong and progressive Cd, Zn, Cu, and Pb contamination gradients between the entrance of the Bay and the north-western anthropized area. On the other hand, low-amplitude natural gradients were observed for other environmental variables. Using 16S rRNA gene sequencing, we observed strong spatial patterns in bacterioplankton taxonomic and predicted function structure along the chemical contamination gradient. Variation partitioning analysis demonstrated that multiple metallic contamination explained the largest part of the spatial biological variations observed, but DOC and salinity were also significant contributors. Network analysis revealed that biotic interactions were far more numerous than direct interactions between microbial groups and environmental variables. This suggests indirect effects of the environment, and especially trace metals, on the community through a few taxonomic groups. These spatial patterns were also partially found for predicted bacterioplankton functions, thus indicating a limited functional redundancy. All these results highlight both potential direct influences of trace metals contamination on coastal bacterioplankton and indirect forcing through biotic interactions and cascading.}, }
@article {pmid30853940, year = {2019}, author = {Jaiswal, S and Singh, DK and Shukla, P}, title = {Gene Editing and Systems Biology Tools for Pesticide Bioremediation: A Review.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {87}, doi = {10.3389/fmicb.2019.00087}, pmid = {30853940}, issn = {1664-302X}, abstract = {Bioremediation is the degradation potential of microorganisms to dissimilate the complex chemical compounds from the surrounding environment. The genetics and biochemistry of biodegradation processes in datasets opened the way of systems biology. Systemic biology aid the study of interacting parts involved in the system. The significant keys of system biology are biodegradation network, computational biology, and omics approaches. Biodegradation network consists of all the databases and datasets which aid in assisting the degradation and deterioration potential of microorganisms for bioremediation processes. This review deciphers the bio-degradation network, i.e., the databases and datasets (UM-BBD, PAN, PTID, etc.) aiding in assisting the degradation and deterioration potential of microorganisms for bioremediation processes, computational biology and multi omics approaches like metagenomics, genomics, transcriptomics, proteomics, and metabolomics for the efficient functional gene mining and their validation for bioremediation experiments. Besides, the present review also describes the gene editing tools like CRISPR Cas, TALEN, and ZFNs which can possibly make design microbe with functional gene of interest for degradation of particular recalcitrant for improved bioremediation.}, }
@article {pmid30852639, year = {2019}, author = {Haro, S and Brodersen, KE and Bohórquez, J and Papaspyrou, S and Corzo, A and Kühl, M}, title = {Radiative Energy Budgets in a Microbial Mat Under Different Irradiance and Tidal Conditions.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {852-865}, doi = {10.1007/s00248-019-01350-6}, pmid = {30852639}, issn = {1432-184X}, support = {CTM2013-43857-R//Ministerio de Economía y Competitividad/ ; DFF-1323-00065B//Ministeriet for Forskning Innovation og Videregående Uddannelser/ ; postdoctoral fellowship//Carlsbergfondet (DK)/ ; PU-2014-043-FPI//Universidad de Cádiz/ ; }, mesh = {*Bacterial Physiological Phenomena ; Denmark ; Geologic Sediments/*microbiology ; Seawater/*microbiology ; *Sunlight ; *Tidal Waves ; }, abstract = {Irradiance and temperature variations during tidal cycles modulate microphytobenthic primary production potentially by changing the radiative energy balance of photosynthetic mats between immersion and emersion and thus sediment daily net metabolism. To test the effect of tidal stages on the radiative energy budget, we used microsensor measurements of oxygen, temperature, and scalar irradiance to estimate the radiative energy budget in a coastal photosynthetic microbial mat during immersion (constant water column of 2 cm) and emersion under increasing irradiance. Total absorbed light energy was higher in immersion than emersion, due to a lower reflectance of the microbial mat, while most (> 97%) of the absorbed light energy was dissipated as heat irrespective of tidal conditions. During immersion, the upward heat flux was higher than the downward one, whereas the opposite occurred during emersion. At highest photon irradiance (800 μmol photon m-2 s-1), the sediment temperature increased ~ 2.5 °C after changing the conditions from immersion to emersion. The radiative energy balance showed that less than 1% of the incident light energy (PAR, 400-700 nm) was conserved by photosynthesis under both tidal conditions. At low to moderate incident irradiances, the light use efficiency was similar during the tidal stages. In contrast, we found an ~ 30% reduction in the light use efficiency during emersion as compared to immersion under the highest irradiance likely due to the rapid warming of the sediment during emersion and increased non-photochemical quenching. These changes in the photosynthetic efficiency and radiative energy budget could affect both primary producers and temperature-dependent bacterial activity and consequently daily net metabolism rates having important ecological consequences.}, }
@article {pmid30852638, year = {2019}, author = {Castle, SC and Samac, DA and Sadowsky, MJ and Rosen, CJ and Gutknecht, JLM and Kinkel, LL}, title = {Impacts of Sampling Design on Estimates of Microbial Community Diversity and Composition in Agricultural Soils.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01318-6}, pmid = {30852638}, issn = {1432-184X}, support = {12108463//Agricultural Research Service/ ; }, abstract = {Soil microbiota play important and diverse roles in agricultural crop nutrition and productivity. Yet, despite increasing efforts to characterize soil bacterial and fungal assemblages, it is challenging to disentangle the influences of sampling design on assessments of communities. Here, we sought to determine whether composite samples-often analyzed as a low cost and effort alternative to replicated individual samples-provide representative summary estimates of microbial communities. At three Minnesota agricultural research sites planted with an oat cover crop, we conducted amplicon sequencing for soil bacterial and fungal communities (16SV4 and ITS2) of replicated individual or homogenized composite soil samples. We compared soil microbiota from within and among plots and then among agricultural sites using both sampling strategies. Results indicated that single or multiple replicated individual samples, or a composite sample from each plot, were sufficient for distinguishing broad site-level macroecological differences among bacterial and fungal communities. Analysis of a single sample per plot captured only a small fraction of the distinct OTUs, diversity, and compositional variability detected in the analysis of multiple individual samples or a single composite sample. Likewise, composite samples captured only a fraction of the diversity represented by the six individual samples from which they were formed, and, on average, analysis of two or three individual samples offered greater compositional coverage (i.e., greater number of OTUs) than a single composite sample. We conclude that sampling design significantly impacts estimates of bacterial and fungal communities even in homogeneously managed agricultural soils, and our findings indicate that while either strategy may be sufficient for broad macroecological investigations, composites may be a poor substitute for replicated samples at finer spatial scales.}, }
@article {pmid30850431, year = {2019}, author = {Schreiber, L and Fortin, N and Tremblay, J and Wasserscheid, J and Elias, M and Mason, J and Sanschagrin, S and Cobanli, S and King, T and Lee, K and Greer, CW}, title = {Potential for Microbially Mediated Natural Attenuation of Diluted Bitumen on the Coast of British Columbia (Canada).}, journal = {Applied and environmental microbiology}, volume = {85}, number = {10}, pages = {}, doi = {10.1128/AEM.00086-19}, pmid = {30850431}, issn = {1098-5336}, abstract = {Western Canada produces large amounts of bitumen, a heavy, highly weathered crude oil. Douglas Channel and Hecate Strait on the coast of British Columbia are two water bodies that may be impacted by a proposed pipeline and marine shipping route for diluted bitumen (dilbit). This study investigated the potential of microbial communities from these waters to mitigate the impacts of a potential dilbit spill. Microcosm experiments were set up with water samples representing different seasons, years, sampling stations, and dilbit blends. While the alkane fraction of the tested dilbit blends was almost completely degraded after 28 days, the majority of the polycyclic aromatic hydrocarbons (PAHs) remained. The addition of the dispersant Corexit 9500A most often had either no effect or an enhancing effect on dilbit degradation. Dilbit-degrading microbial communities were highly variable between seasons, years, and stations, with dilbit type having little impact on community trajectories. Potential oil-degrading genera showed a clear succession pattern and were for the most part recruited from the &quot;rare biosphere.&quot; At the community level, dispersant appeared to stimulate an accelerated enrichment of genera typically associated with hydrocarbon degradation, even in dilbit-free controls. This suggests that dispersant-induced growth of hydrocarbon degraders (and not only increased bioavailability of oil-associated hydrocarbons) contributes to the degradation-enhancing effect previously reported for Corexit 9500A.IMPORTANCE Western Canada hosts large petroleum deposits, which ultimately enter the market in the form of dilbit. Tanker-based shipping represents the primary means to transport dilbit to international markets. With anticipated increases in production to meet global energy needs, the risk of a dilbit spill is expected to increase. This study investigated the potential of microbial communities naturally present in the waters of a potential dilbit shipping lane to mitigate the effects of a spill. Here we show that microbial degradation of dilbit was mostly limited to n-alkanes, while the overall concentration of polycyclic aromatic hydrocarbons, which represent the most toxic fraction of dilbit, decreased only slightly within the time frame of our experiments. We further investigated the effect of the oil dispersant Corexit 9500A on microbial dilbit degradation. Our results highlight the fact that dispersant-associated growth stimulation, and not only increased bioavailability of hydrocarbons and inhibition of specific genera, contributes to the overall effect of dispersant addition.}, }
@article {pmid30847110, year = {2019}, author = {Sharma, RS and Karmakar, S and Kumar, P and Mishra, V}, title = {Application of filamentous phages in environment: A tectonic shift in the science and practice of ecorestoration.}, journal = {Ecology and evolution}, volume = {9}, number = {4}, pages = {2263-2304}, doi = {10.1002/ece3.4743}, pmid = {30847110}, issn = {2045-7758}, abstract = {Theories in soil biology, such as plant-microbe interactions and microbial cooperation and antagonism, have guided the practice of ecological restoration (ecorestoration). Below-ground biodiversity (bacteria, fungi, invertebrates, etc.) influences the development of above-ground biodiversity (vegetation structure). The role of rhizosphere bacteria in plant growth has been largely investigated but the role of phages (bacterial viruses) has received a little attention. Below the ground, phages govern the ecology and evolution of microbial communities by affecting genetic diversity, host fitness, population dynamics, community composition, and nutrient cycling. However, few restoration efforts take into account the interactions between bacteria and phages. Unlike other phages, filamentous phages are highly specific, nonlethal, and influence host fitness in several ways, which make them useful as target bacterial inocula. Also, the ease with which filamentous phages can be genetically manipulated to express a desired peptide to track and control pathogens and contaminants makes them useful in biosensing. Based on ecology and biology of filamentous phages, we developed a hypothesis on the application of phages in environment to derive benefits at different levels of biological organization ranging from individual bacteria to ecosystem for ecorestoration. We examined the potential applications of filamentous phages in improving bacterial inocula to restore vegetation and to monitor changes in habitat during ecorestoration and, based on our results, recommend a reorientation of the existing framework of using microbial inocula for such restoration and monitoring. Because bacterial inocula and biomonitoring tools based on filamentous phages are likely to prove useful in developing cost-effective methods of restoring vegetation, we propose that filamentous phages be incorporated into nature-based restoration efforts and that the tripartite relationship between phages, bacteria, and plants be explored further. Possible impacts of filamentous phages on native microflora are discussed and future areas of research are suggested to preclude any potential risks associated with such an approach.}, }
@article {pmid30846975, year = {2019}, author = {Zorz, J and Willis, C and Comeau, AM and Langille, MGI and Johnson, CL and Li, WKW and LaRoche, J}, title = {Drivers of Regional Bacterial Community Structure and Diversity in the Northwest Atlantic Ocean.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {281}, doi = {10.3389/fmicb.2019.00281}, pmid = {30846975}, issn = {1664-302X}, abstract = {The fundamental role of bacteria in global biogeochemical cycles warrants a thorough understanding of the factors controlling bacterial community structure. In this study, the integrated effect of seasonal differences and spatial distribution on bacterial community structure and diversity were investigated at the regional scale. We conducted a comprehensive bacterial survey, with 451 samples of the Scotian Shelf sector of the Northwest Atlantic Ocean during spring and fall of 2014 and 2016, to analyze the effects of physicochemical gradients on bacterial community structure. Throughout the region, Pelagibacteraceae and Rhodobacteraceae were the most common in the free-living fraction, while Flavobacteriia and Deltaproteobacteria were more abundant in the particle-associated fraction. Overall, there was strong covariation of the microbial community diversity from the two size fractions. This relationship existed despite the statistically significant difference in community structure between the free-living and particle-associated size fractions. In both size fractions, distribution patterns of bacterial taxa, and species within taxa, displayed temporal and spatial preferences. Distinct bacterial assemblages specific to season and depth in the water column were identified. These distinct assemblages, consistent for both 2014 and 2016, suggested replicable patterns in microbial communities for spring and fall in this region. Over all sites, temperature and oxygen values were highly correlated with community similarity, and salinity and oxygen values were the most strongly positively- and negatively correlated with alpha diversity, respectively. However, the strengths of these correlations depended on the depth and season sampled. The bathymetry of the Scotian Shelf, the abrupt shelf break to the Scotian Slope and the major ocean currents dominating in the region led to the formation of distinct on-shelf and off-shelf bacterial communities both in spring and fall. The highest species richness was observed at the shelf break, where water masses from the two major currents meet. Our study establishes the baseline for assessing future changes in the bacterial community of the Scotian Shelf waters, a rapidly changing sector of the Atlantic Ocean.}, }
@article {pmid30837968, year = {2019}, author = {Hinzke, T and Kouris, A and Hughes, RA and Strous, M and Kleiner, M}, title = {More Is Not Always Better: Evaluation of 1D and 2D-LC-MS/MS Methods for Metaproteomics.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {238}, doi = {10.3389/fmicb.2019.00238}, pmid = {30837968}, issn = {1664-302X}, abstract = {Metaproteomics, the study of protein expression in microbial communities, is a versatile tool for environmental microbiology. Achieving sufficiently high metaproteome coverage to obtain a comprehensive picture of the activities and interactions in microbial communities is one of the current challenges in metaproteomics. An essential step to maximize the number of identified proteins is peptide separation via liquid chromatography (LC) prior to mass spectrometry (MS). Thorough optimization and comparison of LC methods for metaproteomics are, however, currently lacking. Here, we present an extensive development and test of different 1D and 2D-LC approaches for metaproteomic peptide separations. We used fully characterized mock community samples to evaluate metaproteomic approaches with very long analytical columns (50 and 75 cm) and long gradients (up to 12 h). We assessed a total of over 20 different 1D and 2D-LC approaches in terms of number of protein groups and unique peptides identified, peptide spectrum matches (PSMs) generated, the ability to detect proteins of low-abundance species, the effect of technical replicate runs on protein identifications and method reproducibility. We show here that, while 1D-LC approaches are faster and easier to set up and lead to more identifications per minute of runtime, 2D-LC approaches allow for a higher overall number of identifications with up to >10,000 protein groups identified. We also compared the 1D and 2D-LC approaches to a standard GeLC workflow, in which proteins are pre-fractionated via gel electrophoresis. This method yielded results comparable to the 2D-LC approaches, however with the drawback of a much increased sample preparation time. Based on our results, we provide recommendations on how to choose the best LC approach for metaproteomics experiments, depending on the study aims.}, }
@article {pmid30834960, year = {2019}, author = {Kerdraon, L and Balesdent, MH and Barret, M and Laval, V and Suffert, F}, title = {Crop Residues in Wheat-Oilseed Rape Rotation System: a Pivotal, Shifting Platform for Microbial Meetings.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {931-945}, doi = {10.1007/s00248-019-01340-8}, pmid = {30834960}, issn = {1432-184X}, support = {634179//Horizon 2020 Framework Programme/ ; }, mesh = {Bacteria/*classification ; Brassica/growth &amp; development ; Crop Production/*methods ; Crops, Agricultural/*growth &amp; development ; DNA Barcoding, Taxonomic ; Fungi/*classification ; *Microbiota ; Seasons ; *Soil Microbiology ; Triticum/growth &amp; development ; }, abstract = {Crop residues are a crucial ecological niche with a major biological impact on agricultural ecosystems. In this study, we used a combined diachronic and synchronic field experiment based on wheat-oilseed rape rotations to test the hypothesis that plant is a structuring factor of microbial communities in crop residues, and that this effect decreases over time with their likely progressive degradation and colonisation by other microorganisms. We characterised an entire fungal and bacterial community associated with 150 wheat and oilseed rape residue samples at a plurennial scale by metabarcoding. The impact of plant species on the residue microbiota decreased over time and our data revealed turnover, with the replacement of oligotrophs, often plant-specific genera (such as pathogens) by copiotrophs, belonging to more generalist genera. Within a single cropping season, the plant-specific genera and species were gradually replaced by taxa that are likely to originate from the soil. These changes occurred more rapidly for bacteria than for fungi, known to degrade complex compounds. Overall, our findings suggest that crop residues constitute a key fully-fledged microbial ecosystem. Taking into account this ecosystem, that has been neglected for too long, is essential, not only to improve the quantitative management of residues, the presence of which can be detrimental to crop health, but also to identify groups of beneficial microorganisms. Our findings are of particular importance, because the wheat-oilseed rape rotation, in which no-till practices are frequent, is particularly widespread in the European arable cropping systems.}, }
@article {pmid30834332, year = {2019}, author = {Dunivin, TK and Choi, J and Howe, A and Shade, A}, title = {RefSoil+: a Reference Database for Genes and Traits of Soil Plasmids.}, journal = {mSystems}, volume = {4}, number = {1}, pages = {}, doi = {10.1128/mSystems.00349-18}, pmid = {30834332}, issn = {2379-5077}, abstract = {Plasmids harbor transferable genes that contribute to the functional repertoire of microbial communities, yet their contributions to metagenomes are often overlooked. Environmental plasmids have the potential to spread antibiotic resistance to clinical microbial strains. In soils, high microbiome diversity and high variability in plasmid characteristics present a challenge for studying plasmids. To improve the understanding of soil plasmids, we present RefSoil+, a database containing plasmid sequences from 922 soil microorganisms. Soil plasmids were larger than other described plasmids, which is a trait associated with plasmid mobility. There was a weak relationship between chromosome size and plasmid size and no relationship between chromosome size and plasmid number, suggesting that these genomic traits are independent in soil. We used RefSoil+ to inform the distributions of antibiotic resistance genes among soil microorganisms compared to those among nonsoil microorganisms. Soil-associated plasmids, but not chromosomes, had fewer antibiotic resistance genes than other microorganisms. These data suggest that soils may offer limited opportunity for plasmid-mediated transfer of described antibiotic resistance genes. RefSoil+ can serve as a reference for the diversity, composition, and host associations of plasmid-borne functional genes in soil, a utility that will be enhanced as the database expands. Our study improves the understanding of soil plasmids and provides a resource for assessing the dynamics of the genes that they carry, especially genes conferring antibiotic resistances. IMPORTANCE Soil-associated plasmids have the potential to transfer antibiotic resistance genes from environmental to clinical microbial strains, which is a public health concern. A specific resource is needed to aggregate the knowledge of soil plasmid characteristics so that the content, host associations, and dynamics of antibiotic resistance genes can be assessed and then tracked between the environment and the clinic. Here, we present RefSoil+, a database of soil-associated plasmids. RefSoil+ presents a contemporary snapshot of antibiotic resistance genes in soil that can serve as a reference as novel plasmids and transferred antibiotic resistances are discovered. Our study broadens our understanding of plasmids in soil and provides a community resource of important plasmid-associated genes, including antibiotic resistance genes.}, }
@article {pmid30834183, year = {2019}, author = {Tormoehlen, K and Johnson-Walker, YJ and Lankau, EW and Myint, MS and Herrmann, JA}, title = {Considerations for studying transmission of antimicrobial resistant enteric bacteria between wild birds and the environment on intensive dairy and beef cattle operations.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6460}, doi = {10.7717/peerj.6460}, pmid = {30834183}, issn = {2167-8359}, abstract = {Background: Wild birds using livestock facilities for food and shelter may contribute to dissemination of enteric pathogens or antimicrobial resistant bacteria. However, drivers of microbial exchange among wildlife and livestock are not well characterized. Predisposition for acquiring and retaining environmental bacteria may vary among species because of physiologic or behavioral differences, complicating selection of a bacterial model that can accurately characterize microbial connections among hosts of interest. This study compares the prevalence and antibiotic resistance phenotypes of two potential model bacterial organisms isolated from wild birds and their environments.<br><br>Methods: We compared prevalence and resistance profiles of Escherichia coli and Enterococcus species isolated from environmental swabs and bird feces on a residential control site, a confinement dairy, a pasture-based beef farm, and a confinement beef farm.<br><br>Results: Bird feces at all sites had low-to-moderate prevalence of Escherichia coli (range: 17-47%), despite potential for exposure on farms (range: 63-97%). Few Escherichia coli were isolated from the control environment. Enterococcus faecalis was dominant in birds at both beef farms (62% and 81% of Enterococcus isolates) and low-to-moderately prevalent at the dairy and control sites (29% and 23% of isolates, respectively). Antimicrobial resistance prevalence was higher in farm samples compared to those from the residential control, but distribution of resistant isolates varied between the bacterial genera. Birds on all farms carried resistant Enterococcus at similar rates to that of the environment, but resistance was less common in bird-associated Escherichia coli despite presence of resistant isolates in the farm environment.<br><br>Discussion: Bacterial species studied may affect how readily bacterial exchange among populations is detected. Selection of microbial models must carefully consider both the questions being posed and how findings might influence resulting management decisions.}, }
@article {pmid30834012, year = {2019}, author = {El-Sayed, H and Aly, Y and Elgamily, H and Nagy, MM}, title = {A Promising Probiotic Irrigant: An In Vitro Study.}, journal = {Open access Macedonian journal of medical sciences}, volume = {7}, number = {3}, pages = {407-411}, doi = {10.3889/oamjms.2019.074}, pmid = {30834012}, issn = {1857-9655}, abstract = {AIM: The present study aimed to investigate the inhibitory effect of Lactobacillus rhamnosus (B-445) as a probiotics irrigant on the growth of Enterococcus faecalis.<br><br>METHODS: Forty-two extracted single human canal anterior teeth were prepared with rotary instrumentation and sterilised. Teeth were divided into 3 groups according to the type of irrigant, N = 14. Three experimental groups were inoculated with E. faecalis and cultured for 21 days before use; Group 1 was 2.5% NaOCl (positive control), Group 2 was saline (negative control), Group 3 was the experimental probiotic irrigant. Paper point sampling of the canals of each group was obtained before irrigation (S1), immediately after irrigation (S2) and after 24 hours (post irrigation samples) (S3) to determine remaining colony forming units for E. faecalis. Also, Colony counts for L. rhamnosus in Group 3 after immediate irrigation, as well as 24 hours post irrigation, was performed to determine the survival profile of these bacteria in infected root canal with E. faecalis.<br><br>RESULTS: The NaOCl irrigant group had the lowest mean value of (log 10 CFU/mL) of E. faecalis after immediate irrigation and after 24 hrs post irrigation followed by the probiotic group, while the highest mean value was the saline group (P ≤ 0.001). The survival profile for L. rhamnosus in Group 3 after immediate irrigation and post-irrigation were slightly higher than for E. faecalis (P ≤ 0.001).<br><br>CONCLUSION: Lactobacillus rhamnosus which revealed a potential inhibitory effect on the growth of Enterococcus faecalis, could be used as a new natural, safe probiotic irrigant agent.}, }
@article {pmid30833723, year = {2019}, author = {Archer, SDJ and Lee, KC and Caruso, T and Maki, T and Lee, CK and Cary, SC and Cowan, DA and Maestre, FT and Pointing, SB}, title = {Airborne microbial transport limitation to isolated Antarctic soil habitats.}, journal = {Nature microbiology}, volume = {4}, number = {6}, pages = {925-932}, doi = {10.1038/s41564-019-0370-4}, pmid = {30833723}, issn = {2058-5276}, abstract = {Dispersal is a critical yet poorly understood factor underlying macroecological patterns in microbial communities1. Airborne microbial transport is assumed to occupy a central role in determining dispersal outcomes2,3, and extra-range dispersal has important implications for predicting ecosystem resilience and response to environmental change4. One of the most pertinent biomes in this regard is Antarctica, given its geographic isolation and vulnerability to climate change and human disturbance5. Here, we report microbial diversity in near-ground and high-altitude air above the largest ice-free Antarctic habitat, as well as that of underlying soil microbial communities. We found that persistent local airborne inputs were unable to fully explain Antarctic soil community assembly. Comparison with airborne microbial diversity from high-altitude and non-polar sources suggests that strong selection occurs during long-range atmospheric transport. The influence of selection during airborne transit and at sink locations varied between microbial phyla. Overall, the communities from this isolated Antarctic ecosystem displayed limited connectivity to the non-polar microbial pool, and alternative sources of recruitment are necessary to fully explain extant soil diversity. Our findings provide critical insights into the role of airborne transport limitation in determining microbial biogeographic patterns.}, }
@article {pmid30832740, year = {2019}, author = {Song, W and Wemheuer, B and Zhang, S and Steensen, K and Thomas, T}, title = {MetaCHIP: community-level horizontal gene transfer identification through the combination of best-match and phylogenetic approaches.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {36}, doi = {10.1186/s40168-019-0649-y}, pmid = {30832740}, issn = {2049-2618}, abstract = {BACKGROUND: Metagenomic datasets provide an opportunity to study horizontal gene transfer (HGT) on the level of a microbial community. However, current HGT detection methods cannot be applied to community-level datasets or require reference genomes. Here, we present MetaCHIP, a pipeline for reference-independent HGT identification at the community level.<br><br>RESULTS: Assessment of MetaCHIP's performance on simulated datasets revealed that it can predict HGTs with various degrees of genetic divergence from metagenomic datasets. The results also indicated that the detection of very recent gene transfers (i.e. those with low levels of genetic divergence) from metagenomics datasets is largely affected by the read assembly step. Comparison of MetaCHIP with a previous analysis on soil bacteria showed a high level of consistency for the prediction of recent HGTs and revealed a large number of additional non-recent gene transfers, which can provide new biological and ecological insight. Assessment of MetaCHIP's performance on real metagenomic datasets confirmed the role of HGT in the spread of genes related to antibiotic resistance in the human gut microbiome. Further testing also showed that functions related to energy production and conversion as well as carbohydrate transport and metabolism are frequently transferred among free-living microorganisms.<br><br>CONCLUSION: MetaCHIP provides an opportunity to study HGTs among members of a microbial community and therefore has several applications in the field of microbial ecology and evolution. MetaCHIP is implemented in Python and freely available at https://github.com/songweizhi/MetaCHIP .}, }
@article {pmid30827722, year = {2019}, author = {Kjølbæk, L and Benítez-Páez, A and Gómez Del Pulgar, EM and Brahe, LK and Liebisch, G and Matysik, S and Rampelli, S and Vermeiren, J and Brigidi, P and Larsen, LH and Astrup, A and Sanz, Y}, title = {Arabinoxylan oligosaccharides and polyunsaturated fatty acid effects on gut microbiota and metabolic markers in overweight individuals with signs of metabolic syndrome: A randomized cross-over trial.}, journal = {Clinical nutrition (Edinburgh, Scotland)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.clnu.2019.01.012}, pmid = {30827722}, issn = {1532-1983}, abstract = {BACKGROUND &amp; AIMS: Gut microbiota composition is linked to obesity and metabolic syndrome. The nutrients and doses required to modulate the gut microbiota towards beneficially influence components of the metabolic syndrome are unclear. This study aimed to investigate diet-induced effects on the gut microbiota and metabolic markers in overweight individuals with indices of the metabolic syndrome.<br><br>METHODS: A twelve-week randomized cross-over trial was conducted with two intervention periods separated by a washout period. The dietary intakes of interest were wheat bran extract, rich in arabinoxylan oligosaccharides (AXOS) (10.4 g/d AXOS) and polyunsaturated fatty acids (PUFA) (3.6 g/d n-3 PUFA). Dietary records, fecal and blood samples, as well as anthropometric data, were collected before and after intervention. Anthropometry and gastrointestinal symptoms were evaluated weekly. Gut microbiota composition was analyzed by massive sequencing of 16S ribosomal RNA gene V3V4 amplicons.<br><br>RESULTS: Twenty-seven participants completed the study (90%). Intake of AXOS induced an expected bifidogenic effect on gut microbiota (p < 0.01) and increased butyrate-producing bacterial species as well (p < 0.05). Beta-diversity analysis indicated that the structure of the gut microbiota only changed as a result of the AXOS intervention (Permanova = 1.90, p < 0.02) and no changes in metabolic markers were observed after any of the interventions.<br><br>CONCLUSIONS: AXOS intake has a bifidogenic effect and also increases butyrate producers in the gut microbiota; even though this type of dietary fiber did not modulate lipid or glucose metabolic parameters related to metabolic syndrome. Four-week PUFA intake did not induce any notable effect on the gut microbiota composition or metabolic risk markers.<br><br>REGISTRATION: Registered under ClinicalTrials.gov Identifier no. NCT02215343.<br><br>CLINICAL TRIAL REGISTRATION: Registered at https://www.clinicaltrials.gov/ (NCT02215343).<br><br>ETHICAL COMMITTEE: H-4-2014-052.<br><br>2013-54-0522.}, }
@article {pmid30823725, year = {2019}, author = {Wang, LZ and Zhao, ZD and Jiang, J and Guo, BH and Wang, X and Huang, ZG and Lai, YC}, title = {A model for meme popularity growth in social networking systems based on biological principle and human interest dynamics.}, journal = {Chaos (Woodbury, N.Y.)}, volume = {29}, number = {2}, pages = {023136}, doi = {10.1063/1.5085009}, pmid = {30823725}, issn = {1089-7682}, abstract = {We analyze five big data sets from a variety of online social networking (OSN) systems and find that the growth dynamics of meme popularity exhibit characteristically different behaviors. For example, there is linear growth associated with online recommendation and sharing platforms, a plateaued (or an &quot;S&quot;-shape) type of growth behavior in a web service devoted to helping users to collect bookmarks, and an exponential increase on the largest and most popular microblogging website in China. Does a universal mechanism with a common set of dynamical rules exist, which can explain these empirically observed, distinct growth behaviors? We provide an affirmative answer in this paper. In particular, inspired by biomimicry to take advantage of cell population growth dynamics in microbial ecology, we construct a base growth model for meme popularity in OSNs. We then take into account human factors by incorporating a general model of human interest dynamics into the base model. The final hybrid model contains a small number of free parameters that can be estimated purely from data. We demonstrate that our model is universal in the sense that, with a few parameters estimated from data, it can successfully predict the distinct meme growth dynamics. Our study represents a successful effort to exploit principles in biology to understand online social behaviors by incorporating the traditional microbial growth model into meme popularity. Our model can be used to gain insights into critical issues such as classification, robustness, optimization, and control of OSN systems.}, }
@article {pmid30822632, year = {2019}, author = {Ahmed, M and Lin, O and Saup, CM and Wilkins, MJ and Lin, LS}, title = {Effects of Fe/S ratio on the kinetics and microbial ecology of an Fe(III)-dosed anaerobic wastewater treatment system.}, journal = {Journal of hazardous materials}, volume = {369}, number = {}, pages = {593-600}, doi = {10.1016/j.jhazmat.2019.02.062}, pmid = {30822632}, issn = {1873-3336}, abstract = {Effects of Fe(III)/sulfate (Fe/S) ratio on organic carbon oxidation kinetics and microbial ecology of a novel Fe(III)-dosed anaerobic wastewater treatment system were investigated in this study. Fixed-film batch bioreactors under three Fe/S molar ratios (1, 2, and 3) yielded COD oxidation rates that increased with the Fe/S ratio, and estimated Michaelis-Menten model parameters Vmax ranging in 0.47-1.09 mg/L⋅min and Km in 2503-3267 mg/L. Both iron and sulfate reducing bacteria contributed to the organics oxidation, and the produced sludge materials contained both biomass (32-45 wt.%) and inorganic precipitates from biogenic ferrous iron and sulfide (68-55 wt.%). Spectroscopic and chemical elemental analyses indicated that the inorganic fraction of the sludge materials contained both FeS and FeS2, and had Fe/S stoichiometric ratios close to 1. Microbiological analyses of the biofilm samples revealed that the major putative iron- and sulfate reducers were Geobacter sp. and Desulfovibrio sp. along with noticeable N-fixing and fermentative bacteria. The COD oxidation rate had a positive correlation with the relative abundance of iron reducers, and both increased with the Fe/S ratio. A conceptual framework was proposed to illustrate the effects of Fe/S ratio on organics oxidation rate, microbial ecology and their interplays.}, }
@article {pmid30820035, year = {2019}, author = {Callieri, C and Slabakova, V and Dzhembekova, N and Slabakova, N and Peneva, E and Cabello-Yeves, PJ and Di Cesare, A and Eckert, EM and Bertoni, R and Corno, G and Salcher, MM and Kamburska, L and Bertoni, F and Moncheva, S}, title = {The mesopelagic anoxic Black Sea as an unexpected habitat for Synechococcus challenges our understanding of global &quot;deep red fluorescence&quot;.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-019-0378-z}, pmid = {30820035}, issn = {1751-7370}, abstract = {The Black Sea is the largest meromictic sea with a reservoir of anoxic water extending from 100 to 1000 m depth. These deeper layers are characterised by a poorly understood fluorescence signal called &quot;deep red fluorescence&quot;, a chlorophyll a- (Chl a) like signal found in deep dark oceanic waters. In two cruises, we repeatedly found up to 103 cells ml-1 of picocyanobacteria at 750 m depth in these waters and isolated two phycoerythrin-rich Synechococcus sp. strains (BS55D and BS56D). Tests on BS56D revealed its high adaptability, involving the accumulation of Chl a in anoxic/dark conditions and its capacity to photosynthesise when re-exposed to light. Whole-genome sequencing of the two strains showed the presence of genes that confirms the putative ability of our strains to survive in harsh mesopelagic environments. This discovery provides new evidence to support early speculations associating the &quot;deep red fluorescence&quot; signal to viable picocyanobacteria populations in the deep oxygen-depleted oceans, suggesting a reconsideration of the ecological role of a viable stock of Synechococcus in dark deep waters.}, }
@article {pmid30818756, year = {2019}, author = {Dong, X and Lv, L and Wang, W and Liu, Y and Yin, C and Xu, Q and Yan, H and Fu, J and Liu, X}, title = {Differences in Distribution of Potassium-Solubilizing Bacteria in Forest and Plantation Soils in Myanmar.}, journal = {International journal of environmental research and public health}, volume = {16}, number = {5}, pages = {}, doi = {10.3390/ijerph16050700}, pmid = {30818756}, issn = {1660-4601}, abstract = {Potassium (K) has been recognized as an essential element in intensive agricultural production systems, and deficiency of K usually results in a decrease in crop yields. The utilization of potassium-solubilizing bacteria (KSB) to increase the soluble K content in soil has been regarded as a desirable pathway to increase plant yields. Following the inoculation of KSB in the soil, potassium can be released (in the form of K⁺) and consumed by plants. This study aims to investigate and compare the distribution characteristics of potassium-solubilizing bacteria between forest and plantation soils in Myanmar. In this study, 14 KSB strains were isolated from rhizosphere samples collected from forest soil, as well as fertilized rubber tree rhizosphere soil and fertilized bare soil from a plantation. Broadleaf forests with high levels of canopy cover mainly comprised the forest environment, and rubber trees were planted in the plantation environment. The Chao and abundance-based coverage estimator (ACE) indices showed that the microbial abundance of the plantation soil was higher than that of the forest soil. According to the Illumina MiSeq sequencing analysis results, the Shannon index of the forest soil was lower while the Simpson index was higher, which demonstrated that the microbial diversity of the forest soil was higher than that of the plantation soil. Potassium-solubilizing test results showed that the strains E, I, M, and N were the most effective KSB under liquid cultivation conditions. Additionally, KSB only accounted for less than 5.47% of the total bacteria detected in either of the sample types, and the distribution of dominant KSB varied with the soil samples. As another result, the abundance of Pseudomonas spp. in S1 was higher than in S2 and S3, indicating a negative impact on the growth of Pseudomonas in the fertilized rubber tree rhizosphere soil. The significance of our research is that it proves that the increasing use of KSB for restoring soil is a good way to reduce the use of chemical fertilizers, which could further provide a relatively stable environment for plant growth.}, }
@article {pmid30814983, year = {2019}, author = {Vandekerckhove, TGL and Bodé, S and De Mulder, C and Vlaeminck, SE and Boon, N}, title = {13C Incorporation as a Tool to Estimate Biomass Yields in Thermophilic and Mesophilic Nitrifying Communities.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {192}, doi = {10.3389/fmicb.2019.00192}, pmid = {30814983}, issn = {1664-302X}, abstract = {Current methods determining biomass yield require sophisticated sensors for in situ measurements or multiple steady-state reactor runs. Determining the yield of specific groups of organisms in mixed cultures in a fast and easy manner remains challenging. This study describes a fast method to estimate the maximum biomass yield (Ymax), based on 13C incorporation during activity measurements. It was applied to mixed cultures containing ammonia oxidizing bacteria (AOB) or archaea (AOA) and nitrite oxidizing bacteria (NOB), grown under mesophilic (15-28°C) and thermophilic (50°C) conditions. Using this method, no distinction could be made between AOB and AOA co-existing in a community. A slight overestimation of the nitrifier biomass due to 13C redirection via SMP to heterotrophs could occur, meaning that this method determines the carbon fixation activity of the autotrophic microorganisms rather than the actual nitrifier biomass yield. Thermophilic AOA yields exceeded mesophilic AOB yields (0.22 vs. 0.06-0.11 g VSS g-1 N), possibly linked to a more efficient pathway for CO2 incorporation. NOB thermophilically produced less biomass (0.025-0.028 vs. 0.048-0.051 g VSS g-1 N), conceivably attributed to higher maintenance requirement, rendering less energy available for biomass synthesis. Interestingly, thermophilic nitrification yield was higher than its mesophilic counterpart, due to the dominance of AOA over AOB at higher temperatures. An instant temperature increase impacted the mesophilic AOB yield, corroborating the effect of maintenance requirement on production capacity. Model simulations of two realistic nitrification/denitrification plants were robust toward changing nitrifier yield in predicting effluent ammonium concentrations, whereas sludge composition was impacted. Summarized, a fast, precise and easily executable method was developed determining Ymax of ammonia and nitrite oxidizers in mixed communities.}, }
@article {pmid30809693, year = {2019}, author = {Zhang, Y and Zhang, LT and Li, ZD and Xin, CX and Li, XQ and Wang, X and Deng, YL}, title = {Microbiomes of China's Space Station During Assembly, Integration, and Test Operations.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01344-4}, pmid = {30809693}, issn = {1432-184X}, support = {31600404//National Natural Science Foundation of China/ ; }, abstract = {Sufficient evidence indicates that orbiting space stations contain diverse microbial populations, which may threaten astronaut health and equipment reliability. Understanding the composition of microbial communities in space stations will facilitate further development of targeted biological safety prevention and maintenance practices. Therefore, this study systematically investigated the microbial community of China's Space Station (CSS). Air and surface samples from 46 sites on the CSS and Assembly Integration and Test (AIT) center were collected, from which 40 bacteria strains were isolated and identified. Most isolates were cold- and desiccation-resistant and adapted to oligotrophic conditions. Bacillus was the dominant bacterial genus detected by both cultivation-based and Illumina MiSeq amplicon sequencing methods. Microbial contamination on the CSS was correlated with encapsulation staff activities. Analysis by spread plate and qPCR revealed that the CSS surface contained 2.24 × 103-5.47 × 103 CFU/100 cm2 culturable bacteria and 9.32 × 105-5.64 × 106 16S rRNA gene copies/100cm2; BacLight™ analysis revealed that the viable/total bacterial cell ratio was 1.98-13.28%. This is the first study to provide important systematic insights into the microbiome of the CSS during assembly that describes the pre-launch microbial diversity of the space station. Our findings revealed the following. (1) Bacillus strains and staff activities should be considered major concerns for future biological safety. (2) Autotrophic and multi-resistant microbial communities were widespread in the AIT environment. Although harsh cleaning methods reduced the number of microorganisms, stress-resistant strains were not completely removed. (3) Sampling, storage and analytical methods for the space station were thoroughly optimized, and are expected to be applicable to low-biomass environments in general. Microbiology-related future works will follow up to comprehensively understand the changing characteristics of microbial communities in CSS.}, }
@article {pmid30809205, year = {2019}, author = {Marco, DE and Abram, F}, title = {Editorial: Using Genomics, Metagenomics and Other &quot;Omics&quot; to Assess Valuable Microbial Ecosystem Services and Novel Biotechnological Applications.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {151}, doi = {10.3389/fmicb.2019.00151}, pmid = {30809205}, issn = {1664-302X}, }
@article {pmid30809011, year = {2019}, author = {Bouma-Gregson, K and Olm, MR and Probst, AJ and Anantharaman, K and Power, ME and Banfield, JF}, title = {Impacts of microbial assemblage and environmental conditions on the distribution of anatoxin-a producing cyanobacteria within a river network.}, journal = {The ISME journal}, volume = {13}, number = {6}, pages = {1618-1634}, doi = {10.1038/s41396-019-0374-3}, pmid = {30809011}, issn = {1751-7370}, support = {91767101-0//U.S. Environmental Protection Agency (US Environmental Protection Agency)/ ; EAR-1331940//National Science Foundation (NSF)/ ; DFG PR 1603/1-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; }, abstract = {Blooms of planktonic cyanobacteria have long been of concern in lakes, but more recently, harmful impacts of riverine benthic cyanobacterial mats been recognized. As yet, we know little about how various benthic cyanobacteria are distributed in river networks, or how environmental conditions or other associated microbes in their consortia affect their biosynthetic capacities. We performed metagenomic sequencing for 22 Oscillatoriales-dominated (Cyanobacteria) microbial mats collected across the Eel River network in Northern California and investigated factors associated with anatoxin-a producing cyanobacteria. All microbial communities were dominated by one or two cyanobacterial species, so the key mat metabolisms involve oxygenic photosynthesis and carbon oxidation. Only a few metabolisms fueled the growth of the mat communities, with little evidence for anaerobic metabolic pathways. We genomically defined four cyanobacterial species, all which shared <96% average nucleotide identity with reference Oscillatoriales genomes and are potentially novel species in the genus Microcoleus. One of the Microcoleus species contained the anatoxin-a biosynthesis genes, and we describe the first anatoxin-a gene cluster from the Microcoleus clade within Oscillatoriales. Occurrence of these four Microcoleus species in the watershed was correlated with total dissolved nitrogen and phosphorus concentrations, and the species that contains the anatoxin-a gene cluster was found in sites with higher nitrogen concentrations. Microbial assemblages in mat samples with the anatoxin-a gene cluster consistently had a lower abundance of Burkholderiales (Betaproteobacteria) species than did mats without the anatoxin-producing genes. The associations of water nutrient concentrations and certain co-occurring microbes with anatoxin-a producing Microcoleus motivate further exploration for their roles as potential controls on the distributions of toxigenic benthic cyanobacteria in river networks.}, }
@article {pmid30808753, year = {2019}, author = {Ramírez-Flandes, S and González, B and Ulloa, O}, title = {Redox traits characterize the organization of global microbial communities.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {9}, pages = {3630-3635}, doi = {10.1073/pnas.1817554116}, pmid = {30808753}, issn = {1091-6490}, mesh = {Ecology ; *Ecosystem ; Humans ; *Metagenomics ; Microbiota/*genetics ; *Oxidation-Reduction ; Soil Microbiology ; }, abstract = {The structure of biological communities is conventionally described as profiles of taxonomic units, whose ecological functions are assumed to be known or, at least, predictable. In environmental microbiology, however, the functions of a majority of microorganisms are unknown and expected to be highly dynamic and collectively redundant, obscuring the link between taxonomic structure and ecosystem functioning. Although genetic trait-based approaches at the community level might overcome this problem, no obvious choice of gene categories can be identified as appropriate descriptive units in a general ecological context. We used 247 microbial metagenomes from 18 biomes to determine which set of genes better characterizes the differences among biomes on the global scale. We show that profiles of oxidoreductase genes support the highest biome differentiation compared with profiles of other categories of enzymes, general protein-coding genes, transporter genes, and taxonomic gene markers. Based on oxidoreductases' description of microbial communities, the role of energetics in differentiation and particular ecosystem function of different biomes become readily apparent. We also show that taxonomic diversity is decoupled from functional diversity, e.g., grasslands and rhizospheres were the most diverse biomes in oxidoreductases but not in taxonomy. Considering that microbes underpin biogeochemical processes and nutrient recycling through oxidoreductases, this functional diversity should be relevant for a better understanding of the stability and conservation of biomes. Consequently, this approach might help to quantify the impact of environmental stressors on microbial ecosystems in the context of the global-scale biome crisis that our planet currently faces.}, }
@article {pmid30808694, year = {2019}, author = {Feng, J and Penton, CR and He, Z and Van Nostrand, JD and Yuan, MM and Wu, L and Wang, C and Qin, Y and Shi, ZJ and Guo, X and Schuur, EAG and Luo, Y and Bracho, R and Konstantinidis, KT and Cole, JR and Tiedje, JM and Yang, Y and Zhou, J}, title = {Long-Term Warming in Alaska Enlarges the Diazotrophic Community in Deep Soils.}, journal = {mBio}, volume = {10}, number = {1}, pages = {}, doi = {10.1128/mBio.02521-18}, pmid = {30808694}, issn = {2150-7511}, mesh = {Alaska ; *Biota ; *Global Warming ; Metagenomics ; Microarray Analysis ; *Nitrogen Fixation ; Oxidoreductases/genetics ; Plant Development ; *Soil Microbiology ; Tundra ; }, abstract = {Tundra ecosystems are typically carbon (C) rich but nitrogen (N) limited. Since biological N2 fixation is the major source of biologically available N, the soil N2-fixing (i.e., diazotrophic) community serves as an essential N supplier to the tundra ecosystem. Recent climate warming has induced deeper permafrost thaw and adversely affected C sequestration, which is modulated by N availability. Therefore, it is crucial to examine the responses of diazotrophic communities to warming across the depths of tundra soils. Herein, we carried out one of the deepest sequencing efforts of nitrogenase gene (nifH) to investigate how 5 years of experimental winter warming affects Alaskan soil diazotrophic community composition and abundance spanning both the organic and mineral layers. Although soil depth had a stronger influence on diazotrophic community composition than warming, warming significantly (P < 0.05) enhanced diazotrophic abundance by 86.3% and aboveground plant biomass by 25.2%. Diazotrophic composition in the middle and lower organic layers, detected by nifH sequencing and a microarray-based tool (GeoChip), was markedly altered, with an increase of α-diversity. Changes in diazotrophic abundance and composition significantly correlated with soil moisture, soil thaw duration, and plant biomass, as shown by structural equation modeling analyses. Therefore, more abundant diazotrophic communities induced by warming may potentially serve as an important mechanism for supplementing biologically available N in this tundra ecosystem.IMPORTANCE With the likelihood that changes in global climate will adversely affect the soil C reservoir in the northern circumpolar permafrost zone, an understanding of the potential role of diazotrophic communities in enhancing biological N2 fixation, which constrains both plant production and microbial decomposition in tundra soils, is important in elucidating the responses of soil microbial communities to global climate change. A recent study showed that the composition of the diazotrophic community in a tundra soil exhibited no change under a short-term (1.5-year) winter warming experiment. However, it remains crucial to examine whether the lack of diazotrophic community responses to warming is persistent over a longer time period as a possibly important mechanism in stabilizing tundra soil C. Through a detailed characterization of the effects of winter warming on diazotrophic communities, we showed that a long-term (5-year) winter warming substantially enhanced diazotrophic abundance and altered community composition, though soil depth had a stronger influence on diazotrophic community composition than warming. These changes were best explained by changes in soil moisture, soil thaw duration, and plant biomass. These results provide crucial insights into the potential factors that may impact future C and N availability in tundra regions.}, }
@article {pmid30806729, year = {2019}, author = {Neupane, S and Modry, D and Pafčo, B and Zurek, L}, title = {Bacterial Community of the Digestive Tract of the European Medicinal Leech (Hirudo verbana) from the Danube River.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1082-1090}, doi = {10.1007/s00248-019-01349-z}, pmid = {30806729}, issn = {1432-184X}, mesh = {Animals ; Bacteria/*classification/genetics ; *Gastrointestinal Microbiome ; Gastrointestinal Tract/microbiology ; Leeches/*microbiology ; RNA, Bacterial/analysis ; RNA, Ribosomal, 16S/analysis ; Rivers ; Romania ; }, abstract = {The digestive tract of medicinal leeches from commercial suppliers has been investigated previously and comprises of a relatively simple bacterial community. However, the microbiome of medicinal leeches collected directly from the natural habitat has not been examined. In this study, we characterized the bacterial community in the digestive tract (anterior crop, posterior crop, and intestine) of the European medicinal leech, Hirudo verbana, collected from the Danube river using culture-independent and culture-dependent approaches. Culture-independent approach confirmed that the digestive tract of H. verbana carries a relatively simple bacterial community with species richness in the individual samples ranging from 43 to164. The dominant bacterial taxon was Mucinivorans sp. (49.7% of total reads), followed by Aeromonas sp. (18.7% of total reads). Several low abundance taxa, new for H. verbana, such as Phreatobacter, Taibaiella, Fluviicola, Aquabacterium, Burkholderia, Hydrogenophaga, Wolinella, and unidentified Chitinophagia, were also detected. The aerobic culturing approach showed Aeromonas veronii (Proteobacteria), the known leech symbiont, as the most dominant taxon followed by several Pseudomonas and Acidovorax spp. No significant differences in the bacterial community composition were detected among different parts of the digestive tract of individual leeches. However, the overall composition of the bacterial community among individual specimen varied significantly and this is possibly due to differences in leech age, feeding status, and blood source. Our results showed that the core bacterial community of H. verbana collected from the natural habitat is similar to that reported from the digestive tract of commercially supplied leeches maintained in the laboratory.}, }
@article {pmid30804920, year = {2019}, author = {Luo, Z and Liu, J and Zhao, P and Jia, T and Li, C and Chai, B}, title = {Biogeographic Patterns and Assembly Mechanisms of Bacterial Communities Differ Between Habitat Generalists and Specialists Across Elevational Gradients.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {169}, doi = {10.3389/fmicb.2019.00169}, pmid = {30804920}, issn = {1664-302X}, abstract = {A core issue in microbial ecology is the need to elucidate the ecological processes and underlying mechanisms involved in microbial community assembly. However, the extent to which these mechanisms differ in importance based on traits of taxa with different niche breadth is poorly understood. Here, we used high-throughput sequencing to examine the relative importance of environmental selection and stochastic processes in shaping soil bacterial sub-communities with different niche breadth (including habitat generalists, specialists and other taxa) across elevational gradients on the subalpine slope of Mount Wutai, Northern China. Our findings suggested that the composition of soil bacterial communities differed significantly different among elevational gradients. According to the niche breadth index, 10.9% of OTUs were defined as habitat generalists (B-value >8.7) and 10.0% of OTUs were defined as habitat specialists (B-value <1.5). Generalists and specialists differed distinctly in diversity and biogeographic patterns across elevational gradients. Environmental selection (deterministic processes) and spatial factors (stochastic processes) seemed to determine the assembly and biogeography of habitat generalists. However, for specialists, deterministic processes strongly influenced the distribution, while stochastic processes were not at play. Environmental drivers for generalists and specialists differed, as did their importance. Elevation, total nitrogen and pH were the main factors determining habitat generalists, and soil water content, nitrate nitrogen and pH had the strongest impacts on specialists. Moreover, variation partitioning analysis revealed that environmental selection had a much greater impact on both generalists (17.7% of pure variance was explained) and specialists (3.6%) than spatial factors. However, generalists had a much stronger response to spatial factors (2.3%) than specialists (0.3%). More importantly, null models of β-diversity suggested that specialists deviated significantly from non-neutral assembly mechanisms (relative null deviation= 0.64-0.74) relative to generalists (0.16-0.65) (P < 0.05). These results indicate that generalists and specialists are governed by different assembly mechanisms and present distinct biogeographical patterns. The large proportion of unexplained variation in specialists (93.3%) implies that very complex assembly mechanisms exist in the assembly of specialists across elevational gradients on the subalpine slope of Mount Wutai. It is essential to understand the microbial community assembly at a more refined level, and to expand the current understanding of microbial ecological mechanisms.}, }
@article {pmid30804907, year = {2019}, author = {Ghosh, P and Sinha, R and Samanta, P and Saha, DR and Koley, H and Dutta, S and Okamoto, K and Ghosh, A and Ramamurthy, T and Mukhopadhyay, AK}, title = {Haitian Variant Vibrio cholerae O1 Strains Manifest Higher Virulence in Animal Models.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {111}, doi = {10.3389/fmicb.2019.00111}, pmid = {30804907}, issn = {1664-302X}, abstract = {Vibrio cholerae causes fatal diarrheal disease cholera in humans due to consumption of contaminated water and food. To instigate the disease, the bacterium must evade the host intestinal innate immune system; penetrate the mucus layer of the small intestine, adhere and multiply on the surface of microvilli and produce toxin(s) through the action of virulence associated genes. V. cholerae O1 that has caused a major cholera outbreak in Haiti contained several unique genetic signatures. These novel traits are used to differentiate them from the canonical El Tor strains. Several studies reported the spread of these Haitian variant strains in different parts of the world including Asia and Africa, but there is a paucity of information on the clinical consequence of these genetic changes. To understand the impact of these changes, we undertook a study involving mice and rabbit models to evaluate the pathogenesis. The colonization ability of Haitian variant strain in comparison to canonical El Tor strain was found to be significantly more in both suckling mice and rabbit model. Adult mice also displayed the same results. Besides that, infection patterns of Haitian variant strains showed a completely different picture. Increased mucosal damaging, colonization, and inflammatory changes were observed through hematoxylin-eosin staining and transmission electron microscopy. Fluid accumulation ability was also significantly higher in rabbit model. Our study indicated that these virulence features of the Haitian variant strain may have some association with the severe clinical outcome of the cholera patients in different parts of the world.}, }
@article {pmid30804904, year = {2019}, author = {Filippidou, S and Junier, T and Wunderlin, T and Kooli, WM and Palmieri, I and Al-Dourobi, A and Molina, V and Lienhard, R and Spangenberg, JE and Johnson, SL and Chain, PSG and Dorador, C and Junier, P}, title = {Adaptive Strategies in a Poly-Extreme Environment: Differentiation of Vegetative Cells in Serratia ureilytica and Resistance to Extreme Conditions.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {102}, doi = {10.3389/fmicb.2019.00102}, pmid = {30804904}, issn = {1664-302X}, abstract = {Poly-extreme terrestrial habitats are often used as analogs to extra-terrestrial environments. Understanding the adaptive strategies allowing bacteria to thrive and survive under these conditions could help in our quest for extra-terrestrial planets suitable for life and understanding how life evolved in the harsh early earth conditions. A prime example of such a survival strategy is the modification of vegetative cells into resistant resting structures. These differentiated cells are often observed in response to harsh environmental conditions. The environmental strain (strain Lr5/4) belonging to Serratia ureilytica was isolated from a geothermal spring in Lirima, Atacama Desert, Chile. The Atacama Desert is the driest habitat on Earth and furthermore, due to its high altitude, it is exposed to an increased amount of UV radiation. The geothermal spring from which the strain was isolated is oligotrophic and the temperature of 54°C exceeds mesophilic conditions (15 to 45°C). Although the vegetative cells were tolerant to various environmental insults (desiccation, extreme pH, glycerol), a modified cell type was formed in response to nutrient deprivation, UV radiation and thermal shock. Scanning (SEM) and Transmission Electron Microscopy (TEM) analyses of vegetative cells and the modified cell structures were performed. In SEM, a change toward a circular shape with reduced size was observed. These circular cells possessed what appears as extra coating layers under TEM. The resistance of the modified cells was also investigated, they were resistant to wet heat, UV radiation and desiccation, while vegetative cells did not withstand any of those conditions. A phylogenomic analysis was undertaken to investigate the presence of known genes involved in dormancy in other bacterial clades. Genes related to spore-formation in Myxococcus and Firmicutes were found in S. ureilytica Lr5/4 genome; however, these genes were not enough for a full sporulation pathway that resembles either group. Although, the molecular pathway of cell differentiation in S. ureilytica Lr5/4 is not fully defined, the identified genes may contribute to the modified phenotype in the Serratia genus. Here, we show that a modified cell structure can occur as a response to extremity in a species that was previously not known to deploy this strategy. This strategy may be widely spread in bacteria, but only expressed under poly-extreme environmental conditions.}, }
@article {pmid30803810, year = {2019}, author = {Puozaa, DK and Jaiswal, SK and Dakora, FD}, title = {Phylogeny and distribution of Bradyrhizobium symbionts nodulating cowpea (Vigna unguiculata L. Walp) and their association with the physicochemical properties of acidic African soils.}, journal = {Systematic and applied microbiology}, volume = {42}, number = {3}, pages = {403-414}, doi = {10.1016/j.syapm.2019.02.004}, pmid = {30803810}, issn = {1618-0984}, abstract = {In the N2-fixing symbiosis, the choice of a symbiotic partner is largely influenced by the host plant, the rhizobial symbiont, as well as soil factors. Understanding the soil environment conducive for the survival and multiplication of root-nodule bacteria is critical for microbial ecology. In this study, we collected cowpea-nodules from acidic soils in Ghana and South Africa, and nodule DNA isolates were characterized using 16S-23S rRNA-RFLP, phylogenetic analysis of housekeeping and symbiotic genes, and bradyrhizobial community structure through canonical correspondence analysis (CCA). The CCA ordination plot results showed that arrow of soil pH was overlapping on CCA2 axis and was the most important to the ordination. The test nodule DNA isolates from Ghana were positively influenced by soil Zn, Na and K while nodule DNA isolates from South Africa were influenced by P. The amplified 16S-23S rRNA region yielded single polymorphic bands of varying lengths (573-1298bp) that were grouped into 28 ITS types. The constructed ITS-dendrogram placed all the nodule DNA isolates in five major clusters at low cut-off of approx. 0.1 Jaccard's similarity coefficient. The phylogenetic analysis of 16S rRNA and housekeeping genes (glnII, gyrB, and atpD) formed distinct Bradyrhizobium groups in the phylogenetic trees. It revealed the presence of highly diverse bradyrhizobia (i.e. Bradyrhizobium vignae, Bradyrhizobium elkanii, Bradyrhizobium iriomotense, Bradyrhizobium pachyrhizi, and Bradyrhizobium yuanmingense) together with novel/unidentified bradyrhizobia in the acidic soils from Ghana and South Africa. Discrepancies noted in the phylogenies of some nodule DNA isolates could be attributed to horizontal gene transfer or recombination.}, }
@article {pmid30802335, year = {2019}, author = {Sáenz, JS and Roldan, F and Junca, H and Arbeli, Z}, title = {Effect of the extraction and purification of soil DNA and pooling of PCR amplification products on the description of bacterial and archaeal communities.}, journal = {Journal of applied microbiology}, volume = {126}, number = {5}, pages = {1454-1467}, doi = {10.1111/jam.14231}, pmid = {30802335}, issn = {1365-2672}, support = {//Pontificia Universidad Javeriana/ ; }, mesh = {Archaea/*genetics ; Bacteria/*genetics ; *DNA, Archaeal/genetics/isolation &amp; purification ; *DNA, Bacterial/genetics/isolation &amp; purification ; Polymerase Chain Reaction ; *Soil Microbiology ; }, abstract = {AIMS: This study evaluated the effects of DNA extraction method, DNA purification and pooling of PCR amplification products on the description of bacterial and archaeal diversity.<br><br>METHODS AND RESULTS: Soil DNA was extracted by the Power Soil DNA extraction kit and a customized Griffiths' protocol. Both methods are based on cell disruption by bead beating. In total, we used three soils and six independent extractions from each soil obtained by each of the two methods. Then, three of the six extracts of each treatment were further purified by spin columns filled with Sepharose 2B and polyvinylpolypyrrolidone (PVPP). The V4 hypervariable region of the 16S rRNA gene was amplified from each extract using the 515F/806R primer pair in four independent reactions. Three amplification products were combined and sequenced as a pooled sample, while the additional amplification product was sequenced individually. The resulting 72 amplification products were sequenced by Illumina MiSeq platform. DNA extraction method had a statistically significant effect on the estimation of the composition of microbial communities that might overwhelm differences in microbial communities from distinct soils. On the other hand, a further DNA purification step or pooling of PCR amplification products had a minor effect on the description of bacterial and archaeal communities.<br><br>CONCLUSIONS: DNA extraction had the strongest effect on the description of bacterial and archaeal communities; low concentration of impurities, which allow PCR amplification, can still generate a minor additional bias, while PCR stochastic variability had the lowest effect.<br><br>Although it is well known that methodological factors affect the description of microbial communities, the relative importance of each step is still unknown. The present study determined that of the factors tested, the DNA extraction method had the strongest effects on the description of bacterial and archaeal communities.}, }
@article {pmid30800101, year = {2019}, author = {Dang, H and Klotz, MG and Lovell, CR and Sievert, SM}, title = {Editorial: The Responses of Marine Microorganisms, Communities and Ecofunctions to Environmental Gradients.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {115}, doi = {10.3389/fmicb.2019.00115}, pmid = {30800101}, issn = {1664-302X}, }
@article {pmid30797477, year = {2019}, author = {Singh, NS and Sharma, R and Singh, DK}, title = {Identification of enzyme(s) capable of degrading endosulfan and endosulfan sulfate using in silico techniques.}, journal = {Enzyme and microbial technology}, volume = {124}, number = {}, pages = {32-40}, doi = {10.1016/j.enzmictec.2019.01.003}, pmid = {30797477}, issn = {1879-0909}, mesh = {Bacillus subtilis/enzymology/metabolism ; Bacterial Proteins/metabolism ; Basidiomycota/enzymology/growth &amp; development/*metabolism ; Biodegradation, Environmental ; Databases, Protein ; Endosulfan/*analogs &amp; derivatives/*metabolism ; Fungal Proteins/metabolism ; Insecticides/*metabolism ; Laccase/metabolism ; Mixed Function Oxygenases/antagonists &amp; inhibitors/*metabolism ; *Molecular Docking Simulation ; }, abstract = {Endosulfan is one of the most widely used organochlorine cyclodiene insecticides. Microbial oxidation of endosulfan forms endosulfan sulfate, which is more or less toxic and persistent as endosulfan. Due to lack of specificity and efficiency of microbial bioremediation technique in the field conditions, enzymatic bioremediation is receiving huge attention to clean-up the environment. In the present study, X-ray crystal structures of enzymes from Brookhaven Protein Data Bank were screened for their potential to degrade endosulfan and endosulfan sulfate using molecular docking and molecular dynamics simulation techniques. A phenol hydroxylase, 1PN0 from Trichosporon cutaneum was found to have the potential to degrade both α-endosulfan and endosulfan sulfate while a bacterial CotA laccase, 3ZDW from Bacillus subtilis has the potential to degrade α-endosulfan. The in silico result correlate with in vitro degradation study using two different strains of Trichosporon cutaneum. In vitro degradation study found that the fungal strain was capable of degrading 60.36% α-endosulfan, 70.73% β-endosulfan, and 52.08% endosulfan sulfate. The presence of phenol hydroxylase inhibitor in the sulfur-free medium with endosulfan and endosulfan sulfate as sole sulfur source inhibits the growth of both the fungal strains. Such in silico techniques can provide an easy and reliable way to speed up the development of bioremediation processes through rapid identification of potential enzymes and microbes to counter the ever-increasing number of toxic compounds in the environment.}, }
@article {pmid30796503, year = {2019}, author = {Lebre, PH and Cowan, DA}, title = {Genomics of Alkaliphiles.}, journal = {Advances in biochemical engineering/biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1007/10_2018_83}, pmid = {30796503}, issn = {0724-6145}, abstract = {Alkalinicity presents a challenge for life due to a &quot;reversed&quot; proton gradient that is unfavourable to many bioenergetic processes across the membranes of microorganisms. Despite this, many bacteria, archaea, and eukaryotes, collectively termed alkaliphiles, are adapted to life in alkaline ecosystems and are of great scientific and biotechnological interest due to their niche specialization and ability to produce highly stable enzymes. Advances in next-generation sequencing technologies have propelled not only the genomic characterization of many alkaliphilic microorganisms that have been isolated from nature alkaline sources but also our understanding of the functional relationships between different taxa in microbial communities living in these ecosystems. In this review, we discuss the genetics and molecular biology of alkaliphiles from an &quot;omics&quot; point of view, focusing on how metagenomics and transcriptomics have contributed to our understanding of these extremophiles. Graphical Abstract.}, }
@article {pmid30796467, year = {2019}, author = {Schlatter, DC and Paul, NC and Shah, DH and Schillinger, WF and Bary, AI and Sharratt, B and Paulitz, TC}, title = {Biosolids and Tillage Practices Influence Soil Bacterial Communities in Dryland Wheat.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01339-1}, pmid = {30796467}, issn = {1432-184X}, abstract = {Class B biosolids are used in dryland wheat (Triticum aestivum L.) production in eastern Washington as a source of nutrients and to increase soil organic matter, but little is known about their effects on bacterial communities and potential for harboring human pathogens. Moreover, conservation tillage is promoted to reduce erosion and soil degradation. We explored the impacts of biosolids or synthetic fertilizer in combination with traditional (conventional) or conservation tillage on soil bacterial communities. Bacterial communities were characterized from fresh biosolids, biosolid aggregates embedded in soil, and soil after a second application of biosolids using high-throughput amplicon sequencing. Biosolid application significantly affected bacterial communities, even 4 years after their application. Bacteria in the families Clostridiaceae, Norcardiaceae, Anaerolinaceae, Dietziaceae, and Planococcaceae were more abundant in fresh biosolids, biosolid aggregates, and soils treated with biosolids than in synthetically fertilized soils. Taxa identified as Turcibacter, Dietzia, Clostridiaceae, and Anaerolineaceae were highly abundant in biosolid aggregates in the soil and likely originated from the biosolids. In contrast, Oxalobacteriaceae, Streptomyceteaceae, Janthinobacterium, Pseudomonas, Kribbella, and Bacillus were rare in the fresh biosolids, but relatively abundant in biosolid aggregates in the soil, and probably originated from the soil to colonize the substrate. However, tillage had relatively minor effects on bacterial communities, with only a small number of taxa differing in relative abundance between traditional and conventional tillage. Although biosolid-associated bacteria persisted in soil, potentially pathogenic taxa were extremely rare and no toxin genes for key groups (Salmonella, Clostridium) were detectable, suggesting that although fecal contamination was apparent via indicator taxa, pathogen populations had declined to low levels. Thus, biosolid amendments had profound effects on soil bacterial communities both by introducing gut- or digester-derived bacteria and by enriching potentially beneficial indigenous soil populations.}, }
@article {pmid30796063, year = {2019}, author = {Heyse, J and Buysschaert, B and Props, R and Rubbens, P and Skirtach, AG and Waegeman, W and Boon, N}, title = {Coculturing Bacteria Leads to Reduced Phenotypic Heterogeneities.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {8}, pages = {}, doi = {10.1128/AEM.02814-18}, pmid = {30796063}, issn = {1098-5336}, abstract = {Isogenic bacterial populations are known to exhibit phenotypic heterogeneity at the single-cell level. Because of difficulties in assessing the phenotypic heterogeneity of a single taxon in a mixed community, the importance of this deeper level of organization remains relatively unknown for natural communities. In this study, we have used membrane-based microcosms that allow the probing of the phenotypic heterogeneity of a single taxon while interacting with a synthetic or natural community. Individual taxa were studied under axenic conditions, as members of a coculture with physical separation, and as a mixed culture. Phenotypic heterogeneity was assessed through both flow cytometry and Raman spectroscopy. Using this setup, we investigated the effect of microbial interactions on the individual phenotypic heterogeneities of two interacting drinking water isolates. Through flow cytometry we have demonstrated that interactions between these bacteria lead to a reduction of their individual phenotypic diversities and that this adjustment is conditional on the bacterial taxon. Single-cell Raman spectroscopy confirmed a taxon-dependent phenotypic shift due to the interaction. In conclusion, our data suggest that bacterial interactions may be a general driver of phenotypic heterogeneity in mixed microbial populations.IMPORTANCE Laboratory studies have shown the impact of phenotypic heterogeneity on the survival and functionality of isogenic populations. Because phenotypic heterogeneity plays an important role in pathogenicity and virulence, antibiotic resistance, biotechnological applications, and ecosystem properties, it is crucial to understand its influencing factors. An unanswered question is whether bacteria in mixed communities influence the phenotypic heterogeneity of their community partners. We found that coculturing bacteria leads to a reduction in their individual phenotypic heterogeneities, which led us to the hypothesis that the individual phenotypic diversity of a taxon is dependent on the community composition.}, }
@article {pmid30793041, year = {2019}, author = {Lee, CK and Laughlin, DC and Bottos, EM and Caruso, T and Joy, K and Barrett, JE and Brabyn, L and Nielsen, UN and Adams, BJ and Wall, DH and Hopkins, DW and Pointing, SB and McDonald, IR and Cowan, DA and Banks, JC and Stichbury, GA and Jones, I and Zawar-Reza, P and Katurji, M and Hogg, ID and Sparrow, AD and Storey, BC and Allan Green, TG and Cary, SC}, title = {Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem.}, journal = {Communications biology}, volume = {2}, number = {}, pages = {62}, doi = {10.1038/s42003-018-0274-5}, pmid = {30793041}, issn = {2399-3642}, abstract = {Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km2. Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.}, }
@article {pmid30792823, year = {2019}, author = {Wu, CH and Ko, JL and Liao, JM and Huang, SS and Lin, MY and Lee, LH and Chang, LY and Ou, CC}, title = {D-methionine alleviates cisplatin-induced mucositis by restoring the gut microbiota structure and improving intestinal inflammation.}, journal = {Therapeutic advances in medical oncology}, volume = {11}, number = {}, pages = {1758835918821021}, doi = {10.1177/1758835918821021}, pmid = {30792823}, issn = {1758-8340}, abstract = {Background: There are close links between chemotherapy-induced intestinal mucositis and microbiota dysbiosis. Previous studies indicated that D-methionine was an excellent candidate for a chemopreventive agent. Here, we investigated the effects of D-methionine on cisplatin-induced mucositis.<br><br>Materials and methods: Male Wistar rats (176-200 g, 6 weeks old) were given cisplatin (5 mg/kg) and treated with D-methionine (300 mg/kg). Histopathological, digestive enzymes activity, oxidative/antioxidant status, proinflammatory/anti-inflammatory cytokines in intestinal tissues were measured. Next-generation sequencing technologies were also performed to investigate the gut microbial ecology.<br><br>Results: D-methionine administration increased villus length and crypt depth and improved digestive enzyme (leucine aminopeptidase, sucrose and alkaline phosphatase) activities in the brush-border membrane of cisplatin-treated rats (p < 0.05). Furthermore, D-methionine significantly attenuated oxidative stress and inflammatory reaction and increased interleukin-10 levels in cisplatin-induced intestinal mucositis (p < 0.05). Cisplatin administration resulted in high relative abundances of Deferribacteres and Proteobacteria and a low diversity of the microbiota when compared with control groups, D-methionine only and cisplatin plus D-methionine. Cisplatin markedly increased comparative abundances of Bacteroides caccae, Escherichia coli, Mucispirillum schaedleri, Bacteroides uniformis and Desulfovibrio C21-c20, while Lactobacillus was almost completely depleted, compared with the control group. There were higher abundances of Lactobacillus, Lachnospiraceae, and Clostridium butyrium in cisplatin plus D-methionine rats than in cisplatin rats. D-methionine treatment alone significantly increased the number of Lactobacillus reuteri.<br><br>Conclusion: D-methionine protects against cisplatin-induced intestinal damage through antioxidative and anti-inflammatory effects. By enhancing growth of beneficial bacteria (Lachnospiraceae and Lactobacillus), D-methionine attenuates gut microbiome imbalance caused by cisplatin and maintains gut homeostasis.}, }
@article {pmid30792705, year = {2019}, author = {Trigodet, F and Larché, N and Morrison, HG and Jebbar, M and Thierry, D and Maignien, L}, title = {Electroactive Bacteria Associated With Stainless Steel Ennoblement in Seawater.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {170}, doi = {10.3389/fmicb.2019.00170}, pmid = {30792705}, issn = {1664-302X}, abstract = {Microorganisms can increase the open-circuit potential of stainless steel immersed in seawater of several hundred millivolts in a phenomenon called ennoblement. It raises the chance of corrosion as the open-circuit potential may go over the pitting corrosion potential. Despite the large impact of the ennoblement, no unifying mechanisms have been described as responsible for the phenomenon. Here we show that the strict electrotroph bacterium &quot;Candidatus Tenderia electrophaga&quot; is detected as an ennoblement biomarker and is only present at temperatures at which we observe ennoblement. This bacterium was previously enriched in biocathode systems. Our results suggest that &quot;Candidatus Tenderia electrophaga,&quot; and its previously described extracellular electron transfer metabolism coupled to oxygen reduction activity, could play a central role in modulating stainless steel open-circuit potential and consequently mediating ennoblement.}, }
@article {pmid30792076, year = {2019}, author = {Álvarez-Pérez, S and Lievens, B and Fukami, T}, title = {Yeast-Bacterium Interactions: The Next Frontier in Nectar Research.}, journal = {Trends in plant science}, volume = {24}, number = {5}, pages = {393-401}, doi = {10.1016/j.tplants.2019.01.012}, pmid = {30792076}, issn = {1878-4372}, abstract = {Beyond its role as a reward for pollinators, floral nectar also provides a habitat for specialized and opportunistic yeasts and bacteria. These microbes modify nectar chemistry, often altering mutualistic relationships between plants and pollinators in ways that we are only beginning to understand. Many studies on this multi-partite system have focused on either yeasts or bacteria without consideration of yeast-bacterium interactions, but recent evidence suggests that such interactions drive the assembly of nectar microbial communities and its consequences for pollination. Unexplored potential mechanisms of yeast-bacterium interactions include the formation of physical complexes, nutritional interactions, antibiosis, signaling-based interactions, and horizontal gene transfer. We argue that studying these mechanisms can elucidate how nectar microbial communities are established and affect plant fitness via pollinators.}, }
@article {pmid30789995, year = {2019}, author = {Martinez, AFC and de Almeida, LG and Moraes, LAB and Cônsoli, FL}, title = {Microbial Diversity and Chemical Multiplicity of Culturable, Taxonomically Similar Bacterial Symbionts of the Leaf-Cutting Ant Acromyrmex coronatus.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1067-1081}, doi = {10.1007/s00248-019-01341-7}, pmid = {30789995}, issn = {1432-184X}, support = {2011/50877-0//Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo/ ; 2014/21584-3//Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo/ ; }, mesh = {Animals ; Ants/*microbiology ; Bacteria/*chemistry/*classification ; Bacterial Physiological Phenomena ; Brazil ; Chromatography, Liquid ; *Microbiota ; *Symbiosis ; Tandem Mass Spectrometry ; }, abstract = {Insects are a highly diverse group, exploit a wide range of habitats, and harbor bacterial symbionts of largely unknown diversity. Insect-associated bacterial symbionts are underexplored but promising sources of bioactive compounds. The community of culturable bacteria associated with the leaf-cutting ant Acromyrmex coronatus (Fabricius) and the diversity of their metabolites produced were investigated. Forty-six phylotypes belonging to Actinobacteria, Firmicutes, and Proteobacteria were identified. The chemical profiles of 65 isolates were further analyzed by LC-MS/MS, and principal components analysis (PCA) was used to group the isolates according to their chemical profiles. Historically, selection of bacterial strains for drug discovery has been based on phenotypic and/or genotypic traits. Use of such traits may well impede the discovery of new compounds; in this study, several indistinguishable phylotypes cultured in identical nutritional and environmental conditions produced completely different chemical profiles. Our data also demonstrated the wide chemical diversity to be explored in insect-associated symbionts.}, }
@article {pmid30787397, year = {2019}, author = {Mansfeldt, C and Achermann, S and Men, Y and Walser, JC and Villez, K and Joss, A and Johnson, DR and Fenner, K}, title = {Microbial residence time is a controlling parameter of the taxonomic composition and functional profile of microbial communities.}, journal = {The ISME journal}, volume = {13}, number = {6}, pages = {1589-1601}, doi = {10.1038/s41396-019-0371-6}, pmid = {30787397}, issn = {1751-7370}, support = {614768//EC | Seventh Framework Programme (EC Seventh Framework Programme)/ ; 614768//EC | Seventh Framework Programme (EC Seventh Framework Programme)/ ; 614768//EC | Seventh Framework Programme (EC Seventh Framework Programme)/ ; }, abstract = {A remaining challenge within microbial ecology is to understand the determinants of richness and diversity observed in environmental microbial communities. In a range of systems, including activated sludge bioreactors, the microbial residence time (MRT) has been previously shown to shape the microbial community composition. However, the physiological and ecological mechanisms driving this influence have remained unclear. Here, this relationship is explored by analyzing an activated sludge system fed with municipal wastewater. Using a model designed in this study based on Monod-growth kinetics, longer MRTs were shown to increase the range of growth parameters that enable persistence, resulting in increased richness and diversity in the modeled community. In laboratory experiments, six sequencing batch reactors treating domestic wastewater were operated in parallel at MRTs between 1 and 15 days. The communities were characterized using both 16S ribosomal RNA and non-target messenger RNA sequencing (metatranscriptomic analysis), and model-predicted monotonic increases in richness were confirmed in both profiles. Accordingly, taxonomic Shannon diversity also increased with MRT. In contrast, the diversity in enzyme class annotations resulting from the metatranscriptomic analysis displayed a non-monotonic trend over the MRT gradient. Disproportionately high abundances of transcripts encoding for rarer enzymes occur at longer MRTs and lead to the disconnect between taxonomic and functional diversity profiles.}, }
@article {pmid30786927, year = {2019}, author = {Kim, SJ and Kim, JG and Lee, SH and Park, SJ and Gwak, JH and Jung, MY and Chung, WH and Yang, EJ and Park, J and Jung, J and Hahn, Y and Cho, JC and Madsen, EL and Rodriguez-Valera, F and Hyun, JH and Rhee, SK}, title = {Genomic and metatranscriptomic analyses of carbon remineralization in an Antarctic polynya.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {29}, doi = {10.1186/s40168-019-0643-4}, pmid = {30786927}, issn = {2049-2618}, abstract = {BACKGROUND: Polynyas in the Southern Ocean are regions of intense primary production, mainly by Phaeocystis antarctica. Carbon fixed by phytoplankton in the water column is transferred to higher trophic levels, and finally, to the deep ocean. However, in the Amundsen Sea, most of this organic carbon does not reach the sediment but is degraded in the water column due to high bacterial heterotrophic activity.<br><br>RESULTS: We reconstructed 12 key bacterial genomes from different phases of bloom and analyzed the expression of genes involved in organic carbon remineralization. A high correlation of gene expression between the peak and decline phases was observed in an individual genome bin-based pairwise comparison of gene expression. Polaribacter belonging to Bacteroidetes was found to be dominant in the peak phase, and its transcriptional activity was high (48.9% of the total mRNA reads). Two dominant Polaribacter bins had the potential to utilize major polymers in P. antarctica, chrysolaminarin and xylan, with a distinct set of glycosyl hydrolases. In the decline phase, Gammaproteobacteria (Ant4D3, SUP05, and SAR92), with the potential to utilize low molecular weight-dissolved organic matter (LMW-DOM) including compatible solutes, was increased. The versatility of Gammaproteobacteria may contribute to their abundance in organic carbon-rich polynya waters, while the SAR11 clade was found to be predominant in the sea ice-covered oligotrophic ocean. SAR92 clade showed transcriptional activity for utilization of both polysaccharides and LMW-DOM; this may account for their abundance both in the peak and decline phases. Ant4D3 clade was dominant in all phases of the polynya bloom, implicating the crucial roles of this clade in LMW-DOM remineralization in the Antarctic polynyas.<br><br>CONCLUSIONS: Genomic reconstruction and in situ gene expression analyses revealed the unique metabolic potential of dominant bacteria of the Antarctic polynya at a finer taxonomic level. The information can be used to predict temporal community succession linked to the availability of substrates derived from the P. antarctica bloom. Global warming has resulted in compositional changes in phytoplankton from P. antarctica to diatoms, and thus, repeated parallel studies in various polynyas are required to predict global warming-related changes in carbon remineralization.}, }
@article {pmid30785932, year = {2019}, author = {Han, SH and Yi, J and Kim, JH and Lee, S and Moon, HW}, title = {Composition of gut microbiota in patients with toxigenic Clostridioides (Clostridium) difficile: Comparison between subgroups according to clinical criteria and toxin gene load.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0212626}, doi = {10.1371/journal.pone.0212626}, pmid = {30785932}, issn = {1932-6203}, abstract = {Data concerning the human microbiota composition during Clostridioides (Clostridium) difficile infection (CDI) using next-generation sequencing are still limited. We aimed to confirm key features indicating tcdB positive patients and compare the microbiota composition between subgroups based on toxin gene load (tcdB gene) and presence of significant diarrhea. Ninety-nine fecal samples from 79 tcdB positive patients and 20 controls were analyzed using 16S rRNA gene sequencing. Chao1 index for alpha diversity were calculated and principal coordinate analysis was performed for beta diversity using Quantitative Insights into Microbial Ecology (QIIME) pipeline. The mean relative abundance in each group was compared at phylum, family, and genus levels. There were significant alterations in alpha and beta diversity in tcdB positive patients (both colonizer and CDI) compared with those in the control. The mean Chao1 index of tcdB positive patients was significantly lower than the control group (P<0.001), whereas there was no significant difference between tcdB groups and between colonizer and CDI. There were significant differences in microbiota compositions between tcdB positive patients and the control at phylum, family, and genus levels. Several genera such as Phascolarctobacterium, Lachnospira, Butyricimonas, Catenibacterium, Paraprevotella, Odoribacter, and Anaerostipes were not detected in most CDI cases. We identified several changes in the microbiota of CDI that could be further evaluated as predictive markers. Microbiota differences between clinical subgroups of CDI need to be further studied in larger controlled studies.}, }
@article {pmid30785875, year = {2019}, author = {Rosa, E and Minard, G and Lindholm, J and Saastamoinen, M}, title = {Moderate plant water stress improves larval development, and impacts immunity and gut microbiota of a specialist herbivore.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0204292}, doi = {10.1371/journal.pone.0204292}, pmid = {30785875}, issn = {1932-6203}, abstract = {While host plant drought is generally viewed as a negative phenomenon, its impact on insect herbivores can vary largely depending on the species involved and on the intensity of the drought. Extreme drought killing host plants can clearly reduce herbivore fitness, but the impact of moderate host plant water stress on insect herbivores can vary, and may even be beneficial. The populations of the Finnish Glanville fritillary butterfly (Melitaea cinxia) have faced reduced precipitation in recent years, with impacts even on population dynamics. Whether the negative effects of low precipitation are solely due to extreme desiccation killing the host plant or whether moderate drought reduces plant quality for the larvae remains unknown. We assessed the performance of larvae fed on moderately water-stressed Plantago lanceolata in terms of growth, survival, and immune response, and additionally were interested to assess whether the gut microbial composition of the larvae changed due to modification of the host plant. We found that larvae fed on water-stressed plants had increased growth, with no impact on survival, up-regulated the expression of one candidate immune gene (pelle), and had a more heterogeneous bacterial community and a shifted fungal community in the gut. Most of the measured traits showed considerable variation due to family structure. Our data suggest that in temperate regions moderate host plant water stress can positively shape resource acquisition of this specialized insect herbivore, potentially by increasing nutrient accessibility or concentration. Potentially, the better larval performance may be mediated by a shift of the microbiota on water-stressed plants, calling for further research especially on the understudied gut fungal community.}, }
@article {pmid30782553, year = {2019}, author = {Díaz Nieto, CH and Palacios, NA and Verbeeck, K and Prévoteau, A and Rabaey, K and Flexer, V}, title = {Membrane electrolysis for the removal of Mg2+ and Ca2+ from lithium rich brines.}, journal = {Water research}, volume = {154}, number = {}, pages = {117-124}, doi = {10.1016/j.watres.2019.01.050}, pmid = {30782553}, issn = {1879-2448}, abstract = {Lithium is today an essential raw material for renewable energy technologies and electric mobility. Continental brines as present in the Lithium Triangle are the most abundant and the easiest to exploit lithium sources. Lithium is present in diluted concentrations together with different ions, and it is imperative to fully remove both magnesium and calcium before lithium carbonate can be precipitated. Here we use membrane electrolysis as a novel method to generate hydroxyl groups in situ in a two-chamber electrochemical cell with a side crystallizer, omitting the need for chemical addition and not leading to substantial loss of lithium rich brine. Batch electrolysis experiments fully removed more than 99.99% of both Mg2+ and Ca2+ for three different native South-American brines treated at current densities ranging from 27 to 350 A m-2 (final concentrations were below ICP detection limit: < 0.05 mg L-1). For a brine containing 3090 mg L-1 of Mg2+ and 685 mg L-1 of Ca2+, 62 kWh m-3 are needed for the full removal of both cations when a current density of 223 A m-2 is employed. Most importantly, the Li+ concentration in the brine is not affected. The removed cations are precipitated as Mg(OH)2 and Ca(OH)2. Our process has the potential to simultaneously recover lithium, magnesium, and calcium compounds, minimizing waste production.}, }
@article {pmid30778376, year = {2019}, author = {Zeng, X and Gao, X and Peng, Y and Wu, Q and Zhu, J and Tan, C and Xia, G and You, C and Xu, R and Pan, S and Zhou, H and He, Y and Yin, J}, title = {Higher Risk of Stroke Is Correlated With Increased Opportunistic Pathogen Load and Reduced Levels of Butyrate-Producing Bacteria in the Gut.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {4}, doi = {10.3389/fcimb.2019.00004}, pmid = {30778376}, issn = {2235-2988}, abstract = {Objective: Gut microbiota is a newly identified risk factor for stroke, and there are no large prospective studies linking the baseline gut microbiome to long-term risk of stroke. We present here the correlation between the gut microbiota and stroke risk in people with no prior stroke history. Methods: A total of 141 participants aged ≥60 years without prior history of stroke were recruited and divided into low-risk, medium-risk, and high-risk groups based on known risk factors and whether they were suffering from chronic diseases. The composition of their gut microbiomes was compared using 16S rRNA gene amplicon next-generation-sequencing and Quantitative Insights into Microbial Ecology (QIIME) analysis. Levels of fecal short-chain fatty acids were measured using gas chromatography. Results: We found that opportunistic pathogens (e.g., Enterobacteriaceae and Veillonellaceae) and lactate-producing bacteria (e.g., Bifidobacterium and Lactobacillus) were enriched, while butyrate-producing bacteria (e.g., Lachnospiraceae and Ruminococcaceae) were depleted, in the high-risk group compared to the low-risk group. Butyrate concentrations were also lower in the fecal samples obtained from the high-risk group than from the low-risk group. The concentrations of other short-chain fatty acids (e.g., acetate, propionate, isobutyrate, isovalerate, and valerate) in the gut were comparable among the three groups. Conclusion: Participants at high risk of stroke were characterized by the enrichment of opportunistic pathogens, low abundance of butyrate-producing bacteria, and reduced concentrations of fecal butyrate. More researches into the gut microbiota as a risk factor in stroke should be carried out in the near future.}, }
@article {pmid30775415, year = {2018}, author = {Photos-Jones, E and Knapp, CW and Venieri, D and Christidis, GE and Elgy, C and Valsami-Jones, E and Gounaki, I and Andriopoulou, NC}, title = {Greco-Roman mineral (litho)therapeutics and their relationship to their microbiome: The case of the red pigment miltos.}, journal = {Journal of archaeological science, reports}, volume = {22}, number = {}, pages = {179-192}, doi = {10.1016/j.jasrep.2018.07.017}, pmid = {30775415}, issn = {2352-409X}, support = {//Wellcome Trust/United Kingdom ; }, abstract = {This paper introduces a holistic approach to the study of Greco-Roman (G-R) lithotherapeutics. These are the minerals or mineral combinations that appear in the medical and scientific literature of the G-R world. It argues that they can best be described not simply in terms of their bulk chemistry/mineralogy but also their ecological microbiology and nanofraction component. It suggests that each individual attribute may have underpinned the bioactivity of the lithotherapeutic as an antibacterial, antifungal or other. We focus on miltos, the highly prized, naturally fine, red iron oxide-based mineral used as a pigment, in boat maintenance, agriculture and medicine. Five samples (four geological (from Kea, N. Cyclades) and one archaeological (from Lemnos, NE Aegean)) of miltos were analyzed with physical and biological science techniques. We show that: a. Kean miltos and Lemnian earth/miltos must have been chemically and mineralogically different; b. Lemnian miltos must have been more effective as an antibacterial against specific pathogens (Gram + and Gram - bacteria) than its Kean counterpart; c. two samples of Kean miltos, although similar, chemically, mineralogically and eco-microbiologically (phylum/class level), nevertheless, displayed different antibacterial action. We suggest that this may constitute proof of microbial ecology playing an important role in effecting bioactivity and, interestingly, at the more specific genus/species level. From the perspective of the historian of G-R science, we suggest that it may have been on account of its bioactivity, rather than simply its 'red-staining' effect, that miltos gained prominent entry into the scientific and medical literature of the G-R world.}, }
@article {pmid30772540, year = {2019}, author = {Reid, T and Droppo, IG and Chaganti, SR and Weisener, CG}, title = {Microbial metabolic strategies for overcoming low-oxygen in naturalized freshwater reservoirs surrounding the Athabasca Oil Sands: A proxy for End-Pit Lakes?.}, journal = {The Science of the total environment}, volume = {665}, number = {}, pages = {113-124}, doi = {10.1016/j.scitotenv.2019.02.032}, pmid = {30772540}, issn = {1879-1026}, mesh = {Alberta ; Ecosystem ; *Environmental Monitoring ; Eutrophication ; Lakes/*chemistry/microbiology ; Mining ; *Oil and Gas Fields ; *Water Microbiology ; Water Pollutants, Chemical/*analysis ; }, abstract = {The success and sustainability of aquatic ecosystems are driven by the complex, cooperative metabolism of microbes. Ecological engineering strategies often strive to harness this syntrophic synergy of microbial metabolism for the reclamation of contaminated environments worldwide. Currently, there is a significant knowledge gap in our understanding of how the natural microbial ecology overcomes thermodynamic limitations in recovering contaminated environments. Here, we used in-situ metatranscriptomics and associated metataxonomic analyses on sediments collected from naturalized freshwater man-made reservoirs within the Athabasca Oil Sands region of Alberta, Canada. These reservoirs are unique since they are untouched by industrial mining processes and serve as representative endpoints for model landscape reconstruction. Results indicate that a microbial syntrophic cooperation has been established represented by the oxygenic and anoxygenic phototrophs, sustained through the efficient use of novel cellular mechanistic adaptations tailored to these unique thermodynamic conditions. Specifically, chemotaxis transcripts (cheY &amp; MCPs-methyl-accepting chemotaxis proteins) were highly expressed, suggesting a highly active microbial response to gradients in environmental stimuli, resulting indirectly from hydrocarbon compound alteration. A high expression of photosynthetic activity, likely sustaining nutrient delivery to the similarly highly expressed methanogenic community acting in syntrophy during the breakdown of organics. Overall the more diversified functionality within sub-oxic sample locations indicates an ability to maintain efficient metabolism under thermodynamic constraints. This is the first study to holistically identify and characterize these types of in-situ, metabolic processes and address their thermodynamic feasibility within a global context for large landscape reconstruction. These characterizations of regional, natural landscapes surrounding the oil sands mining operation are severely lacking, but truly provide invaluable insight into end-point goals and targets for reclamation procedures.}, }
@article {pmid30771735, year = {2019}, author = {Petersen, C and Wankhade, UD and Bharat, D and Wong, K and Mueller, JE and Chintapalli, SV and Piccolo, BD and Jalili, T and Jia, Z and Symons, JD and Shankar, K and Anandh Babu, PV}, title = {Dietary supplementation with strawberry induces marked changes in the composition and functional potential of the gut microbiome in diabetic mice.}, journal = {The Journal of nutritional biochemistry}, volume = {66}, number = {}, pages = {63-69}, doi = {10.1016/j.jnutbio.2019.01.004}, pmid = {30771735}, issn = {1873-4847}, support = {R03 AG052848/AG/NIA NIH HHS/United States ; }, abstract = {Gut microbiota contributes to the biological activities of berry anthocyanins by transforming them into bioactive metabolites, and anthocyanins support the growth of specific bacteria, indicating a two-way relationship between anthocyanins and microbiota. In the present study, we tested the hypothesis that strawberry supplementation alters gut microbial ecology in diabetic db/db mice. Control (db/+) and diabetic (db/db) mice (7 weeks old) consumed standard diet or diet supplemented with 2.35% freeze-dried strawberry (db/db + SB) for 10 weeks. Colon contents were used to isolate bacterial DNA. V4 variable region of 16S rRNA gene was amplified. Data analyses were performed using standardized pipelines (QIIME 1.9 and R packages). Differences in predictive metagenomics function were identified by PICRUSt. Principal coordinate analyses confirmed that the microbial composition was significantly influenced by both host genotype and strawberry consumption. Further, α-diversity indices and β-diversity were different at the phylum and genus levels, and genus and operational taxonomical units levels, respectively (P<.05). At the phylum level, strawberry supplementation decreased the abundance of Verrucomicrobia in db/db + SB vs. db/db mice (P<.05). At the genus level, db/db mice exhibited a decrease in the abundance of Bifidobacterium, and strawberry supplementation increased Bifidobacterium in db/db + SB vs. db/db mice (P<.05). PICRUSt revealed significant differences in 45 predicted metabolic functions among the 3 groups. Our study provides evidence for marked changes in the composition and functional potential of the gut microbiome with strawberry supplementation in diabetic mice. Importantly, strawberry supplementation increased the abundance of beneficial bacteria Bifidobacterium which play a pivotal role in the metabolism of anthocyanins.}, }
@article {pmid30770943, year = {2019}, author = {Lewis, RW and Islam, A and Opdahl, L and Davenport, JR and Sullivan, TS}, title = {Comparative Genomics, Siderophore Production, and Iron Scavenging Potential of Root Zone Soil Bacteria Isolated from 'Concord' Grape Vineyards.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01324-8}, pmid = {30770943}, issn = {1432-184X}, support = {3319-3259//Washington State Concord Grape Research Council/ ; 3019-8894/3387//Washington State University Center for Sustaining Agriculture and Natural Resources/ ; }, abstract = {Iron (Fe) deficiency in crop production is a worldwide problem which often results in chlorosis in grapevines, particularly in calcareous soils. Siderophores secreted by microorganisms and Strategy II plants can chelate Fe and other metals in soil solution, and siderophore-Fe complexes can then be utilized by plants and microbes. Plants may also shift rhizosphere conditions to favor siderophore-producing microbes, which can increase plant available Fe. Between-row cover crops (barley, rye, wheat, wheat/vetch) were planted as living mulch to address grapevine chlorosis by enhancing soil health in two vineyards in central Washington. The objectives of the current study were to (1) enrich for siderophore-producing organisms from within the indigenous rooting zone community of 'Concord' grapevines, and (2) perform comparative genomics on putative siderophore producing organisms to assess potentially important Fe acquisition-related functional domains and protein families. A high-throughput, chrome azurol S (CAS)-based enrichment assay was used to select siderophore-producing microbes from 'Concord' grapevine root zone soil. Next-generation whole genome sequencing allowed the assembly and annotation of ten full genomes. Phylogenetic analysis revealed two distinct clades among the genomes using the 40 nearest neighbors available in the public database, all of which were of the Pseudomonas genus. Significant differences in functional domain abundances were observed between the clades including iron acquisition and metabolism of amino acids, carbon, nitrogen, phosphate, and sulfur. Diverse mechanisms of Fe uptake and siderophore production/uptake were identified in the protein families of the genomes. The sequenced organisms are likely pseudomonads which are well-suited for iron scavenging, suggesting a potential role in Fe turnover in vineyard systems.}, }
@article {pmid30769104, year = {2019}, author = {Conrads, G and Abdelbary, MMH}, title = {Challenges of next-generation sequencing targeting anaerobes.}, journal = {Anaerobe}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.anaerobe.2019.02.006}, pmid = {30769104}, issn = {1095-8274}, abstract = {Next-generation sequencing allows for investigating the composition of microbiomes that are associated with infection (clinical microbiology) or dysbiosis (microbial ecology). The most commonly applied short-read sequencing technologies are Illumina MiSeq/HiSeq and Ion Torrent PGM, however, other platforms that generate long-reads are under way and optimized. A pre-condition for representative results is an appropriate method for contamination-free collection, homogenization, storage of specimens and a subsequent efficient DNA extraction protocol. As some of the anaerobes such as Clostridia or anaerobe Archaea are robust while others of the same environment, such as spirochetes, possess a very thin cell wall, a chemico-mechanical lysing strategy is recommended but with some precautions to avoid DNA-sheering and overheating. For amplicon sequencing, the Silva-TestPrime online tool helps to find the optimal 16S directed primers for individual studies. For metagenome profiling, the classifier tool has to be selected with helpful decision trees available but a combination based on different strategies seems to be indispensable. Further development of both hard- and software is needed before microbiome results become free of a substantial technology-dependent bias.}, }
@article {pmid30768364, year = {2019}, author = {Kain, V and Van Der Pol, W and Mariappan, N and Ahmad, A and Eipers, P and Gibson, DL and Gladine, C and Vigor, C and Durand, T and Morrow, C and Halade, GV}, title = {Obesogenic diet in aging mice disrupts gut microbe composition and alters neutrophil:lymphocyte ratio, leading to inflamed milieu in acute heart failure.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {33}, number = {5}, pages = {6456-6469}, doi = {10.1096/fj.201802477R}, pmid = {30768364}, issn = {1530-6860}, support = {R01 HL132989/HL/NHLBI NIH HHS/United States ; R00 AT006704/AT/NCCIH NIH HHS/United States ; P30 AR050948/AR/NIAMS NIH HHS/United States ; UL1 TR001417/TR/NCATS NIH HHS/United States ; K99 AT006704/AT/NCCIH NIH HHS/United States ; }, abstract = {Calorie-dense obesogenic diet (OBD) is a prime risk factor for cardiovascular disease in aging. However, increasing age coupled with changes in the diet can affect the interaction of intestinal microbiota influencing the immune system, which can lead to chronic inflammation. How age and calorie-enriched OBD interact with microbial flora and impact leukocyte profiling is currently under investigated. Here, we tested the interorgan hypothesis to determine whether OBD in young and aging mice alters the gut microbe composition and the splenic leukocyte profile in acute heart failure (HF). Young (2-mo-old) and aging (18-mo-old) mice were supplemented with standard diet (STD, ∼4% safflower oil diet) and OBD (10% safflower oil) for 2 mo and then subjected to coronary artery ligation to induce myocardial infarction. Fecal samples were collected pre- and post-diet intervention, and the microbial flora were analyzed using 16S variable region 4 rRNA gene DNA sequencing and Quantitative Insights Into Microbial Ecology informatics. The STD and OBD in aging mice resulted in an expansion of the genus Allobaculum in the fecal microbiota. However, we found a pathologic change in the neutrophil:lymphocyte ratio in aging mice in comparison with their young counterparts. Thus, calorie-enriched OBD dysregulated splenic leukocytes by decreasing immune-responsive F4/80+ and CD169+ macrophages in aging mice. OBD programmed neutrophil swarming with an increase in isoprostanoid levels, with dysregulation of lipoxygenases, cytokines, and metabolite-sensing receptor expression. In summary, calorie-dense OBD in aging mice disrupted the composition of the gut microbiome, which correlates with the development of integrative and system-wide nonresolving inflammation in acute HF.-Kain, V., Van Der Pol, W., Mariappan, N., Ahmad, A., Eipers, P., Gibson, D. L., Gladine, C., Vigor, C., Durand, T., Morrow, C., Halade, G. V. Obesogenic diet in aging mice disrupts gut microbe composition and alters neutrophil:lymphocyte ratio, leading to inflamed milieu in acute heart failure.}, }
@article {pmid30767956, year = {2019}, author = {Bai, J and Jhaney, I and Daniel, G and Watkins Bruner, D}, title = {Pilot Study of Vaginal Microbiome Using QIIME 2™ in Women With Gynecologic Cancer Before and After Radiation Therapy.}, journal = {Oncology nursing forum}, volume = {46}, number = {2}, pages = {E48-E59}, doi = {10.1188/19.ONF.E48-E59}, pmid = {30767956}, issn = {1538-0688}, abstract = {OBJECTIVES: To characterize the vaginal microbiome using QIIME 2™ (Quantitative Insights Into Microbial Ecology 2) in women with gynecologic cancer.<br><br>SAMPLE &amp;AMP; SETTING: 19 women with gynecologic cancer before and after radiation therapy at a comprehensive cancer center in Atlanta, Georgia.<br><br>METHODS &amp;AMP; VARIABLES: This pilot study analyzed vaginal microbiome communities using a microbiome analysis pipeline, beginning with 16S rRNA gene sequencing and processing through use of a bioinformatics pipeline to downstream microbial statistical analysis.<br><br>RESULTS: The findings showed the methods to be robust, and most women with gynecologic cancer showed depletion of Lactobacillus. Compared to those pre-radiation therapy, women post-radiation therapy showed higher abundances of Mobiluncus, Atopobium, and Prevotella but lower abundances of Lactobacillus, Gardnerella, and Peptostreptococcus, which are associated with bacterial vaginosis.<br><br>IMPLICATIONS FOR NURSING: This study presents the fundamentals of human microbiome data collection and analysis methods to inform nursing science. Assessing the vaginal microbiome provides a potential pathway to develop interventions to ameliorate dysbiosis of the vaginal microbiome.}, }
@article {pmid30762095, year = {2019}, author = {Martínez-Rodríguez, P and Rolán-Alvarez, E and Del Mar Pérez-Ruiz, M and Arroyo-Yebras, F and Carpena-Catoira, C and Carvajal-Rodríguez, A and Bella, JL}, title = {Geographic and Temporal Variation of Distinct Intracellular Endosymbiont Strains of Wolbachia sp. in the Grasshopper Chorthippus parallelus: a Frequency-Dependent Mechanism?.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1036-1047}, doi = {10.1007/s00248-019-01338-2}, pmid = {30762095}, issn = {1432-184X}, support = {CGL2016-75482-P//Ministerio de Ciencia y Tecnolog?a/ ; BFU2013-44635//Ministerio de Econom?a, Industria y Competitividad, Gobierno de Espa?a/ ; }, mesh = {Animals ; Biological Coevolution ; Computer Simulation ; Geography ; Grasshoppers/*microbiology ; Linear Models ; *Polymorphism, Genetic ; Seasons ; *Symbiosis ; Wolbachia/genetics/*physiology ; }, abstract = {Wolbachia is an intracellular endosymbiont that can produce a range of effects on host fitness, but the temporal dynamics of Wolbachia strains have rarely been experimentally evaluated. We compare interannual strain frequencies along a geographical region for understanding the forces that shape Wolbachia strain frequency in natural populations of its host, Chorthippus parallelus (Orthoptera, Acrididae). General linear models show that strain frequency changes significantly across geographical and temporal scales. Computer simulation allows to reject the compatibility of the observed patterns with either genetic drift or sampling errors. We use consecutive years to estimate total Wolbachia strain fitness. Our estimation of Wolbachia fitness is significant in most cases, within locality and between consecutive years, following a negatively frequency-dependent trend. Wolbachia spp. B and F strains show a temporal pattern of variation that is compatible with a negative frequency-dependent natural selection mechanism. Our results suggest that such a mechanism should be at least considered in future experimental and theoretical research strategies that attempt to understand Wolbachia biodiversity.}, }
@article {pmid30761424, year = {2019}, author = {Parera-Valadez, Y and Yam-Puc, A and López-Aguiar, LK and Borges-Argáez, R and Figueroa-Saldivar, MA and Cáceres-Farfán, M and Márquez-Velázquez, NA and Prieto-Davó, A}, title = {Ecological Strategies Behind the Selection of Cultivable Actinomycete Strains from the Yucatan Peninsula for the Discovery of Secondary Metabolites with Antibiotic Activity.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {839-851}, doi = {10.1007/s00248-019-01329-3}, pmid = {30761424}, issn = {1432-184X}, support = {CVU223481//Consejo Nacional de Ciencia y Tecnolog?a/ ; PNC//Consejo Nacional de Ciencia y Tecnolog?a/ ; TA200212, TA200415//Direcci?n General de Asuntos del Personal Acad?mico, Universidad Nacional Aut?noma de M?xico/ ; }, mesh = {Actinobacteria/*chemistry ; Anti-Bacterial Agents/*analysis ; Biological Products/*analysis ; Drug Discovery/*methods ; Mexico ; Seawater/*analysis ; }, abstract = {The quest for novel natural products has recently focused on the marine environment as a source for novel microorganisms. Although isolation of marine-derived actinomycete strains is now common, understanding their distribution in the oceans and their adaptation to this environment can be helpful in the selection of isolates for further novel secondary metabolite discovery. This study explores the taxonomic diversity of marine-derived actinomycetes from distinct environments in the coastal areas of the Yucatan Peninsula and their adaptation to the marine environment as a first step towards novel natural product discovery. The use of simple ecological principles, for example, phylogenetic relatedness to previously characterized actinomycetes or seawater requirements for growth, to recognize isolates with adaptations to the ocean in an effort to select for marine-derived actinomycete to be used for further chemical studies. Marine microbial environments are an important source of novel bioactive natural products and, together with methods such as genome mining for detection of strains with biotechnological potential, ecological strategies can bring useful insights in the selection and identification of marine-derived actinomycetes for novel natural product discovery.}, }
@article {pmid30761423, year = {2019}, author = {Purahong, W and Kahl, T and Krüger, D and Buscot, F and Hoppe, B}, title = {Home-Field Advantage in Wood Decomposition Is Mainly Mediated by Fungal Community Shifts at &quot;Home&quot; Versus &quot;Away&quot;.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01334-6}, pmid = {30761423}, issn = {1432-184X}, support = {KR 3587/1-1, KR 3587/3-2//Deutsche Forschungsgemeinschaft/ ; BU 941/17-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The home-field advantage (HFA) hypothesis has been used intensively to study leaf litter decomposition in various ecosystems. However, the HFA in woody substrates is still unexplored. Here, we reanalyzed and integrated existing datasets on various groups of microorganisms collected from natural deadwood of two temperate trees, Fagus sylvatica and Picea abies, from forests in which one or other of these species dominates but where both are present. Our aims were (i) to test the HFA hypothesis on wood decomposition rates of these two temperate tree species, and (ii) to investigate if HFA hypothesis can be explained by diversity and community composition of bacteria and in detail N-fixing bacteria (as determined by molecular 16S rRNA and nifH gene amplification) and fungi (as determined by molecular ITS rRNA amplification and sporocarp surveys). Our results showed that wood decomposition rates were accelerated at &quot;home&quot; versus &quot;away&quot; by 38.19% ± 20.04% (mean ± SE). We detected strong changes in fungal richness (increase 36-50%) and community composition (RANOSIM = 0.52-0.60, P < 0.05) according to HFA hypothesis. The changes of fungi were much stronger than for total bacteria and nitrogen fixing for both at richness and community composition levels. In conclusion, our results support the HFA hypothesis in deadwood: decomposition rate is accelerated at home due to specialization of fungal communities produced by the plant community above them. Furthermore, the higher richness of fungal sporocarps and nitrogen-fixing bacteria (nifH) may stimulate or at least stabilize wood decomposition rates at &quot;home&quot; versus &quot;away.&quot;}, }
@article {pmid30759613, year = {2019}, author = {Wang, X and Li, X and Yu, L and Huang, L and Xiu, J and Lin, W and Zhang, Y}, title = {Characterizing the microbiome in petroleum reservoir flooded by different water sources.}, journal = {The Science of the total environment}, volume = {653}, number = {}, pages = {872-885}, doi = {10.1016/j.scitotenv.2018.10.410}, pmid = {30759613}, issn = {1879-1026}, mesh = {Betaproteobacteria/genetics/*metabolism ; China ; Environmental Monitoring ; Gammaproteobacteria/genetics/*metabolism ; Metagenomics ; *Microbiota/genetics ; Oil and Gas Fields/*microbiology ; Petroleum/*metabolism ; Phylogeny ; RNA, Ribosomal, 16S ; Water Microbiology ; *Water Resources/supply &amp; distribution ; }, abstract = {Petroleum reservoir is an unusual subsurface biosphere, where indigenous microbes lived and evolved for million years. However, continual water injection changed the situation by introduction of new electron acceptors, donors and exogenous microbes. In this study, 16S-rRNA gene sequencing, comparative metagenomics and genomic bins reconstruction were employed to investigate the microbial community and metabolic potential in three typical water-flooded blocks of the Shen84 oil reservoir in Liaohe oil field, China. The results showed significant difference of microbial community compositions and metabolic characteristics existed between the injected water and the produced water/oil mixtures; however, there was considerable uniformity between the produced samples in different blocks. Microbial communities in the produced fluids were dominated by exogenous facultative microbes such as Pseudomonas and Thauera members from Proteobacteria phylum. Metabolic potentials for O2-dependent hydrocarbon degradation, dissimilarly nitrate reduction, and thiosulfate‑sulfur oxidation were much more abundant, whereas genes involved in dissimilatory sulfate reduction, anaerobic hydrocarbon degradation and methanogenesis were less abundant in the oil reservoir. Statistical analysis indicated the water composition had an obvious influence on microbial community composition and metabolic potential. The water-flooding process accompanied with introduction of nitrate or nitrite, and dissolved oxygen promoted the alteration of microbiome in oil reservoir from slow-growing anaerobic indigenous microbes (such as Thermotoga, Clostridia, and Syntrophobacter) to fast-growing opportunists as Beta- and Gama- Proteobacteria. The findings of this study shed light on the microbial ecology change in water flooded petroleum reservoir.}, }
@article {pmid30759269, year = {2019}, author = {Semenec, L and Vergara, IA and Laloo, AE and Mathews, ER and Bond, PL and Franks, AE}, title = {Enhanced Growth of Pilin-Deficient Geobacter sulfurreducens Mutants in Carbon Poor and Electron Donor Limiting Conditions.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01316-8}, pmid = {30759269}, issn = {1432-184X}, support = {N626909-13-1-N259//Office of Naval Research Global/ ; FA2386-14-1-4032//Asian Office of Aerospace Research and Development/ ; LP140100459//Australian Research Council/ ; }, abstract = {Geobacter sulfurreducens pili enable extracellular electron transfer and play a role in secretion of c-type cytochromes such as OmcZ. PilA-deficient mutants of G. sulfurreducens have previously been shown to accumulate cytochromes within their membranes. This cytochrome retaining phenotype allowed for enhanced growth of PilA-deficient mutants in electron donor and carbon-limited conditions where formate and fumarate are provided as the sole electron donor and acceptor with no supplementary carbon source. Conversely, wild-type G. sulfurreducens, which has normal secretion of cytochromes, has comparative limited growth in these conditions. This growth is further impeded for OmcZ-deficient and OmcS-deficient mutants. A PilB-deficient mutant which prevents pilin production but allows for secretion of OmcZ had moderate growth in these conditions, indicating a role for cytochrome localization to enabling survival in the electron donor and carbon-limited conditions. To determine which pathways enhanced growth using formate, Sequential Window Acquisition of all Theoretical Mass Spectra mass spectrometry (SWATH-MS) proteomics of formate adapted PilA-deficient mutants and acetate grown wild type was performed. PilA-deficient mutants had an overall decrease in tricarboxylic acid (TCA) cycle enzymes and significant upregulation of electron transport chain associated proteins including many c-type cytochromes and [NiFe]-hydrogenases. Whole genome sequencing of the mutants shows strong convergent evolution and emergence of genetic subpopulations during adaptation to growth on formate. The results described here suggest a role for membrane constrained c-type cytochromes to the enhancement of survival and growth in electron donor and carbon-limited conditions.}, }
@article {pmid30759084, year = {2019}, author = {Hawinkel, S and Kerckhof, FM and Bijnens, L and Thas, O}, title = {A unified framework for unconstrained and constrained ordination of microbiome read count data.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0205474}, doi = {10.1371/journal.pone.0205474}, pmid = {30759084}, issn = {1932-6203}, abstract = {Explorative visualization techniques provide a first summary of microbiome read count datasets through dimension reduction. A plethora of dimension reduction methods exists, but many of them focus primarily on sample ordination, failing to elucidate the role of the bacterial species. Moreover, implicit but often unrealistic assumptions underlying these methods fail to account for overdispersion and differences in sequencing depth, which are two typical characteristics of sequencing data. We combine log-linear models with a dispersion estimation algorithm and flexible response function modelling into a framework for unconstrained and constrained ordination. The method is able to cope with differences in dispersion between taxa and varying sequencing depths, to yield meaningful biological patterns. Moreover, it can correct for observed technical confounders, whereas other methods are adversely affected by these artefacts. Unlike distance-based ordination methods, the assumptions underlying our method are stated explicitly and can be verified using simple diagnostics. The combination of unconstrained and constrained ordination in the same framework is unique in the field and facilitates microbiome data exploration. We illustrate the advantages of our method on simulated and real datasets, while pointing out flaws in existing methods. The algorithms for fitting and plotting are available in the R-package RCM.}, }
@article {pmid30758801, year = {2019}, author = {Kiewra, D and Czułowska, A and Dyczko, D and Zieliński, R and Plewa-Tutaj, K}, title = {First record of Haemaphysalis concinna (Acari: Ixodidae) in Lower Silesia, SW Poland.}, journal = {Experimental &amp; applied acarology}, volume = {77}, number = {3}, pages = {449-454}, doi = {10.1007/s10493-019-00344-w}, pmid = {30758801}, issn = {1572-9702}, abstract = {Haemaphysalis concinna Koch is one of 19 species of the genus Haemaphysalis which has been reported in the Palearctic region. In Europe, the presence of H. concinna ticks has been reported in numerous countries. In Poland, to date, the precise occurrence of H. concinna was known only from one site in the north-western region. This paper shows that H. concinna ticks can be considered a typical example of the tick fauna occurring in Lower Silesia, SW Poland. Tick monitoring was conducted using a standard flagging method in 24 sites in the various forest types of Lower Silesia. Among 1622 host-seeking ticks collected, H. concinna accounted for 2.7%. From the collected H. concinna there were: 25 (58.1%) larvae, 15 (34.9%) nymphs, 1 (2.3%) female, and 2 (4.7%) males. The presence of H. concinna was confirmed in 6 out of 24 tested sites in fresh mixed broadleaf forests, fresh mixed coniferous forests and in pastures.}, }
@article {pmid30756135, year = {2019}, author = {Singer, D and Metz, S and Unrein, F and Shimano, S and Mazei, Y and Mitchell, EAD and Lara, E}, title = {Contrasted Micro-Eukaryotic Diversity Associated with Sphagnum Mosses in Tropical, Subtropical and Temperate Climatic Zones.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01325-7}, pmid = {30756135}, issn = {1432-184X}, support = {310003A//Schweizerischer Nationalfonds zur F?rderung der Wissenschaftlichen Forschung/ ; 143960//Schweizerischer Nationalfonds zur F?rderung der Wissenschaftlichen Forschung/ ; ASTF 520 - 2015//European Molecular Biology Organization/ ; FONCyT PICT-2014-1290//Consejo Nacional de Investigaciones Cient?ficas y T?cnicas/ ; }, abstract = {Sphagnum-dominated ecosystem plays major roles as carbon sinks at the global level. Associated microbial communities, in particular, eukaryotes, play significant roles in nutrient fixation and turnover. In order to understand better the ecological processes driven by these organisms, the first step is to characterise these associated organisms. We characterised the taxonomic diversity, and from this, inferred the functional diversity of microeukaryotes in Sphagnum mosses in tropical, subtropical and temperate climatic zones through an environmental DNA diversity metabarcoding survey of the V9 region of the gene coding for the RNA of the small subunit of the ribosomes (SSU rRNA). As microbial processes are strongly driven by temperatures, we hypothesised that saprotrophy would be highest in warm regions, whereas mixotrophy, an optimal strategy in oligotrophic environments, would peak under colder climates. Phylotype richness was higher in tropical and subtropical climatic zones than in the temperate region, mostly due to a higher diversity of animal parasites (i.e. Apicomplexa). Decomposers, and especially opportunistic yeasts and moulds, were more abundant under warmer climates, while mixotrophic organisms were more abundant under temperate climates. The dominance of decomposers, suggesting a higher heterotrophic activity under warmer climates, is coherent with the generally observed faster nutrient cycling at lower latitudes; this phenomenon is likely enhanced by higher inputs of nutrients most probably brought in the system by Metazoa, such as arthropods.}, }
@article {pmid30755506, year = {2019}, author = {Hausmann, B and Pelikan, C and Rattei, T and Loy, A and Pester, M}, title = {Long-Term Transcriptional Activity at Zero Growth of a Cosmopolitan Rare Biosphere Member.}, journal = {mBio}, volume = {10}, number = {1}, pages = {}, doi = {10.1128/mBio.02189-18}, pmid = {30755506}, issn = {2150-7511}, mesh = {Bacterial Load ; Biomass ; Gene Expression Profiling ; Genome, Bacterial ; Metagenomics ; Peptococcaceae/*genetics/*growth &amp; development ; Real-Time Polymerase Chain Reaction ; Sequence Analysis, DNA ; Soil Microbiology ; *Transcription, Genetic ; }, abstract = {Microbial diversity in the environment is mainly concealed within the rare biosphere (all species with <0.1% relative abundance). While dormancy explains a low-abundance state very well, the mechanisms leading to rare but active microorganisms remain elusive. We used environmental systems biology to genomically and transcriptionally characterize &quot;Candidatus Desulfosporosinus infrequens,&quot; a low-abundance sulfate-reducing microorganism cosmopolitan to freshwater wetlands, where it contributes to cryptic sulfur cycling. We obtained its near-complete genome by metagenomics of acidic peat soil. In addition, we analyzed anoxic peat soil incubated under in situ-like conditions for 50 days by Desulfosporosinus-targeted qPCR and metatranscriptomics. The Desulfosporosinus population stayed at a constant low abundance under all incubation conditions, averaging 1.2 × 106 16S rRNA gene copies per cm³ soil. In contrast, transcriptional activity of &quot;Ca. Desulfosporosinus infrequens&quot; increased at day 36 by 56- to 188-fold when minor amendments of acetate, propionate, lactate, or butyrate were provided with sulfate, compared to the no-substrate-control. Overall transcriptional activity was driven by expression of genes encoding ribosomal proteins, energy metabolism, and stress response but not by expression of genes encoding cell growth-associated processes. Since our results did not support growth of these highly active microorganisms in terms of biomass increase or cell division, they had to invest their sole energy for maintenance, most likely counterbalancing acidic pH conditions. This finding explains how a rare biosphere member can contribute to a biogeochemically relevant process while remaining in a zero-growth state over a period of 50 days.IMPORTANCE The microbial rare biosphere represents the largest pool of biodiversity on Earth and constitutes, in sum of all its members, a considerable part of a habitat's biomass. Dormancy or starvation is typically used to explain the persistence of low-abundance microorganisms in the environment. We show that a low-abundance microorganism can be highly transcriptionally active while remaining in a zero-growth state for at least 7 weeks. Our results provide evidence that this zero growth at a high cellular activity state is driven by maintenance requirements. We show that this is true for a microbial keystone species, in particular a cosmopolitan but permanently low-abundance sulfate-reducing microorganism in wetlands that is involved in counterbalancing greenhouse gas emissions. In summary, our results provide an important step forward in understanding time-resolved activities of rare biosphere members relevant for ecosystem functions.}, }
@article {pmid30747342, year = {2019}, author = {Faulkner, M and Zhao, LS and Barrett, S and Liu, LN}, title = {Self-Assembly Stability and Variability of Bacterial Microcompartment Shell Proteins in Response to the Environmental Change.}, journal = {Nanoscale research letters}, volume = {14}, number = {1}, pages = {54}, doi = {10.1186/s11671-019-2884-3}, pmid = {30747342}, issn = {1931-7573}, support = {UF120411//Royal Society/ ; RG130442//Royal Society/ ; URF\R\180030//Royal Society/ ; RGF\EA\180233//Royal Society/ ; BB/M024202/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R003890/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Bacterial microcompartments (BMCs) are proteinaceous self-assembling organelles that are widespread among the prokaryotic kingdom. By segmenting key metabolic enzymes and pathways using a polyhedral shell, BMCs play essential roles in carbon assimilation, pathogenesis, and microbial ecology. The BMC shell is composed of multiple protein homologs that self-assemble to form the defined architecture. There is tremendous interest in engineering BMCs to develop new nanobioreactors and molecular scaffolds. Here, we report the quantitative characterization of the formation and self-assembly dynamics of BMC shell proteins under varying pH and salt conditions using high-speed atomic force microscopy (HS-AFM). We show that 400-mM salt concentration is prone to result in larger single-layered shell patches formed by shell hexamers, and a higher dynamic rate of hexamer self-assembly was observed at neutral pH. We also visualize the variability of shell proteins from hexameric assemblies to fiber-like arrays. This study advances our knowledge about the stability and variability of BMC protein self-assemblies in response to microenvironmental changes, which will inform rational design and construction of synthetic BMC structures with the capacity of remodeling their self-assembly and structural robustness. It also offers a powerful toolbox for quantitatively assessing the self-assembly and formation of BMC-based nanostructures in biotechnology applications.}, }
@article {pmid30746494, year = {2019}, author = {Tecon, R and Mitri, S and Ciccarese, D and Or, D and van der Meer, JR and Johnson, DR}, title = {Bridging the Holistic-Reductionist Divide in Microbial Ecology.}, journal = {mSystems}, volume = {4}, number = {1}, pages = {}, doi = {10.1128/mSystems.00265-18}, pmid = {30746494}, issn = {2379-5077}, abstract = {Microbial communities are inherently complex systems. To address this complexity, microbial ecologists are developing new, more elaborate laboratory models at an ever-increasing pace. These model microbial communities and habitats have opened up the exploration of new territories that lie between the simplicity and controllability of &quot;synthetic&quot; systems and the convolution and complexity of natural environments. Here, we discuss this classic methodological divide, we propose a conceptual perspective that integrates new research developments, and we sketch a 3-point possible roadmap to cross the divide between controllability and complexity in microbial ecology.}, }
@article {pmid30745899, year = {2018}, author = {Eveillard, D and Bouskill, NJ and Vintache, D and Gras, J and Ward, BB and Bourdon, J}, title = {Probabilistic Modeling of Microbial Metabolic Networks for Integrating Partial Quantitative Knowledge Within the Nitrogen Cycle.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3298}, doi = {10.3389/fmicb.2018.03298}, pmid = {30745899}, issn = {1664-302X}, abstract = {Understanding the interactions between microbial communities and their environment sufficiently to predict diversity on the basis of physicochemical parameters is a fundamental pursuit of microbial ecology that still eludes us. However, modeling microbial communities is problematic, because (i) communities are complex, (ii) most descriptions are qualitative, and (iii) quantitative understanding of the way communities interact with their surroundings remains incomplete. One approach to overcoming such complications is the integration of partial qualitative and quantitative descriptions into more complex networks. Here we outline the development of a probabilistic framework, based on Event Transition Graph (ETG) theory, to predict microbial community structure across observed chemical data. Using reverse engineering, we derive probabilities from the ETG that accurately represent observations from experiments and predict putative constraints on communities within dynamic environments. These predictions can feedback into the future development of field experiments by emphasizing the most important functional reactions, and associated microbial strains, required to characterize microbial ecosystems.}, }
@article {pmid30743865, year = {2018}, author = {Pikaar, I and de Vrieze, J and Rabaey, K and Herrero, M and Smith, P and Verstraete, W}, title = {Carbon emission avoidance and capture by producing in-reactor microbial biomass based food, feed and slow release fertilizer: Potentials and limitations.}, journal = {The Science of the total environment}, volume = {644}, number = {}, pages = {1525-1530}, doi = {10.1016/j.scitotenv.2018.07.089}, pmid = {30743865}, issn = {1879-1026}, mesh = {Biomass ; *Bioreactors ; Carbon ; Carbon Cycle ; *Carbon Sequestration ; Climate Change ; *Fertilizers ; }, abstract = {To adhere to the Paris Agreement of 2015, we need to store several Gigatonnes (Gt) of carbon annually. In the last years, a variety of technologies for carbon capture and storage (CCS) and carbon capture and usage (CCU) have been demonstrated. While conventional CCS and CCU are techno-economically feasible, their climate change mitigation potentials are limited, due to limited amount of CO2 that can be captured. Hence, there is an urgent need to explore other CCS and CCU routes. Here we discuss an interesting alternative route for capture of carbon dioxide from industrial point sources, using CO2-binding, so-called autotrophic aerobic bacteria to produce microbial biomass as a C-storage product. The produced microbial biomass is often referred to as microbial protein (MP) because it has a crude protein content of ~70-75%. Depending on the industrial production process and final quality of the produced MP, it can be used for human consumption as meat replacement, protein supplement in animal diets, or slow-release organic fertilizer thus providing both organic nitrogen and carbon to agricultural soils. Here, we discuss the potentials and limitations of this so far unexplored CCU approach. A preliminary assessment of the economic feasibility of the different routes for CO2 carbon avoidance, capture and utilization indicates that the value chain to food is becoming attractive and that the other end-points warrant close monitoring over the coming years.}, }
@article {pmid30742313, year = {2019}, author = {Noor, NM and Defoirdt, T and Alipiah, N and Karim, M and Daud, H and Natrah, I}, title = {Quorum sensing is required for full virulence of Vibrio campbellii towards tiger grouper (Epinephelus fuscoguttatus) larvae.}, journal = {Journal of fish diseases}, volume = {42}, number = {4}, pages = {489-495}, doi = {10.1111/jfd.12946}, pmid = {30742313}, issn = {1365-2761}, support = {BOF-UGent//Universiteit Gent/ ; GP-HIP/2018/9598400//Universiti Putra Malaysia/ ; //Malaysian Ministry of Education/ ; }, mesh = {4-Butyrolactone/analogs &amp; derivatives/genetics ; Animals ; Bass/*microbiology ; Fish Diseases/*microbiology ; Homoserine/analogs &amp; derivatives/genetics ; Lactones ; Larva/microbiology ; Mutation ; *Quorum Sensing ; Vibrio/genetics/*metabolism/*pathogenicity ; Virulence ; }, abstract = {The link between quorum sensing in Vibrio campbellii and its virulence towards tiger grouper (Epinephelus fuscoguttatus) was investigated using V. campbellii wild type and quorum-sensing mutants with inactive quorum sensing or constitutively maximal quorum-sensing activity, and signal molecule synthase mutants. The results showed that wild-type V. campbellii is pathogenic to grouper larvae, causing more than 50% mortality after 4 days of challenge. Furthermore, the mortality of larvae challenged with the mutant with maximally active quorum sensing was significantly higher than that of larvae challenged with the wild type, whereas a higher survival was observed in the larvae challenged to the mutant with a completely inactive quorum-sensing system. Grouper larvae challenged with either the signal molecule synthase triple mutant, the harveyi autoinducer-1 (HAI-1) synthase mutant and the autoinducer-2 (AI-2) synthase mutant showed higher survival than larvae challenged with the wild type. In contrast, larvae challenged with the cholerae autoinducer-1 (CAI-1) synthase mutant showed high mortality. This indicates that HAI-1 and AI-2, but not CAI-1, are required for full virulence of V. campbellii towards grouper larvae. Our data suggest that quorum-sensing inhibition could be an effective strategy to control V. campbellii infections in tiger grouper.}, }
@article {pmid30740279, year = {2019}, author = {Lee, KM and Adams, M and Klassen, JL}, title = {Evaluation of DESS as a storage medium for microbial community analysis.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6414}, doi = {10.7717/peerj.6414}, pmid = {30740279}, issn = {2167-8359}, abstract = {Microbial ecology research requires sampling strategies that accurately represent the microbial community under study. These communities must typically be transported from the collection location to the laboratory and then stored until they can be processed. However, there is a lack of consensus on how best to preserve microbial communities during transport and storage. Here, we evaluated dimethyl sulfoxide, ethylenediamine tetraacetic acid, saturated salt (DESS) solution as a broadly applicable preservative for microbial ecology experiments. We stored fungus gardens grown by the ant Trachymyrmex septentrionalis in DESS, 15% glycerol, and phosphate buffered saline (PBS) to test their impact on the fungus garden microbial community. Variation in microbial community structure due to differences in preservative type was minimal when compared to variation between ant colonies. Additionally, DESS preserved the structure of a defined mock community more faithfully than either 15% glycerol or PBS. DESS is inexpensive, easy to transport, and effective in preserving microbial community structure. We therefore conclude that DESS is a valuable preservative for use in microbial ecology research.}, }
@article {pmid30739147, year = {2019}, author = {Pastor, A and Freixa, A and Skovsholt, LJ and Wu, N and Romaní, AM and Riis, T}, title = {Microbial Organic Matter Utilization in High-Arctic Streams: Key Enzymatic Controls.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01330-w}, pmid = {30739147}, issn = {1432-184X}, support = {CF16-0325//Carlsbergfondet/ ; Postgraduate studies program//Fundaci?n Ram?n Areces/ ; }, abstract = {In the Arctic, climate changes contribute to enhanced mobilization of organic matter in streams. Microbial extracellular enzymes are important mediators of stream organic matter processing, but limited information is available on enzyme processes in this remote area. Here, we studied the variability of microbial extracellular enzyme activity in high-Arctic fluvial biofilms. We evaluated 12 stream reaches in Northeast Greenland draining areas exhibiting different geomorphological features with contrasting contents of soil organic matter to cover a wide range of environmental conditions. We determined stream nitrogen, phosphorus, and dissolved organic carbon concentrations, quantified algal biomass and bacterial density, and characterized the extracellular enzyme activities involved in catalyzing the cleavage of a range of organic matter compounds (e.g., β-glucosidase, phosphatase, β-xylosidase, cellobiohydrolase, and phenol oxidase). We found significant differences in microbial organic matter utilization among the study streams draining contrasting geomorphological features, indicating a strong coupling between terrestrial and stream ecosystems. Phosphatase and phenol oxidase activities were higher in solifluction areas than in alluvial areas. Besides dissolved organic carbon, nitrogen availability was the main driver controlling enzyme activities in the high-Arctic, which suggests enhanced organic matter mineralization at increased nutrient availability. Overall, our study provides novel information on the controls of organic matter usage by high-Arctic stream biofilms, which is of high relevance due to the predicted increase of nutrient availability in high-Arctic streams in global climate change scenarios.}, }
@article {pmid30739041, year = {2019}, author = {Camacho-Montealegre, CM and Rodrigues, EM and Tótola, MR}, title = {Microbial diversity and bioremediation of rhizospheric soils from Trindade Island - Brazil.}, journal = {Journal of environmental management}, volume = {236}, number = {}, pages = {358-364}, doi = {10.1016/j.jenvman.2019.02.013}, pmid = {30739041}, issn = {1095-8630}, abstract = {Pristine environments may harbor complex microbial communities with metabolic potential for use in bioremediation of organic pollutants. This study aimed to evaluate crude oil biodegradation by microbial communities present in rhizospheric soils of Bulbostylis nesiotis and Cyperus atlanticus on Trindade Island and the compositional structure of these communities. After 60 days under aerobic conditions, Total Petroleum Hydrocarbon biodegradation ranged from 66 to 75%, depending on the plant species and the origin of the soil samples. There was no response of petroleum biodegradation to fertilization with N:P:K (80:160:80 mg dm-3). Soil contamination with crude oil did not necessarily reduce microbial diversity. The richness and diversity increased in contaminated soils in some specific situations. We conclude that microbial communities from pristine soils have the ability to remove hydrocarbons through biodegradation and that Bulbostylis nesiotis and Cyperus atlanticus inhabiting Trindade Island harbor rhizospheric microbial communities with potential for application in rhizoremediation.}, }
@article {pmid30738110, year = {2019}, author = {Mateus-Barros, E and Meneghine, AK and Bagatini, IL and Fernandes, CC and Kishi, LT and Vieira, AAH and Sarmento, H}, title = {Comparison of two DNA extraction methods widely used in aquatic microbial ecology.}, journal = {Journal of microbiological methods}, volume = {159}, number = {}, pages = {12-17}, doi = {10.1016/j.mimet.2019.02.005}, pmid = {30738110}, issn = {1872-8359}, abstract = {In recent years, the rapid advances of culture-independent methods and new molecular tools have revolutionized our understanding of microbial biodiversity and ecological functions. DNA extraction from microbial communities is a critical step in this process and several methods have been proposed and used, but the influence of the extraction method on the outcome and ultimately on ecological inferences from the results is not yet precisely determined. Here, we compared two of the most commonly used extraction methods in aquatic microbial ecology, and investigated whether the two methods yielded comparable results for community ecology analyses. We extracted DNA from 15 different shallow lakes with phenol:chloroform, a classical and widely used extraction method, and with the PowerSoil DNA isolation Kit, often suggested as the standard DNA extraction method, with some adaptations for aquatic environments. We found that although only 5% of all OTUs showed significant differences in pairwise comparisons (using the 15 lakes as replicates), these OTUs accounted for >35% (on average) of the relative abundance. Diversity and richness did not differ significantly between the two extraction methods, but the beta-dispersion of the communities indicated that the organic extraction yielded more homogeneous communities, while the kit extraction generated variability. Consequently, we conclude that despite the small number of OTUs with significant differences, their impact on the community composition obtained was not negligible, and therefore the results from these two extraction methods were not comparable.}, }
@article {pmid30735594, year = {2019}, author = {Ferguson, RMW and Garcia-Alcega, S and Coulon, F and Dumbrell, AJ and Whitby, C and Colbeck, I}, title = {Bioaerosol biomonitoring: Sampling optimization for molecular microbial ecology.}, journal = {Molecular ecology resources}, volume = {19}, number = {3}, pages = {672-690}, doi = {10.1111/1755-0998.13002}, pmid = {30735594}, issn = {1755-0998}, support = {NE/M010813/1//Natural Environment Research Council/ ; }, mesh = {*Aerosols ; *Air Microbiology ; Bacteria/*classification/*isolation &amp; purification ; Environmental Monitoring/*methods ; }, abstract = {Bioaerosols (or biogenic aerosols) have largely been overlooked by molecular ecologists. However, this is rapidly changing as bioaerosols play key roles in public health, environmental chemistry and the dispersal ecology of microbes. Due to the low environmental concentrations of bioaerosols, collecting sufficient biomass for molecular methods is challenging. Currently, no standardized methods for bioaerosol collection for molecular ecology research exist. Each study requires a process of optimization, which greatly slows the advance of bioaerosol science. Here, we evaluated air filtration and liquid impingement for bioaerosol sampling across a range of environmental conditions. We also investigated the effect of sampling matrices, sample concentration strategies and sampling duration on DNA yield. Air filtration using polycarbonate filters gave the highest recovery, but due to the faster sampling rates possible with impingement, we recommend this method for fine -scale temporal/spatial ecological studies. To prevent bias for the recovery of Gram-positive bacteria, we found that the matrix for impingement should be phosphate-buffered saline. The optimal method for bioaerosol concentration from the liquid matrix was centrifugation. However, we also present a method using syringe filters for rapid in-field recovery of bioaerosols from impingement samples, without compromising microbial diversity for high -throughput sequencing approaches. Finally, we provide a resource that enables molecular ecologists to select the most appropriate sampling strategy for their specific research question.}, }
@article {pmid30735001, year = {2019}, author = {Cassman, NA and Soares, JR and Pijl, A and Lourenço, KS and van Veen, JA and Cantarella, H and Kuramae, EE}, title = {Nitrification inhibitors effectively target N2 O-producing Nitrosospira spp. in tropical soil.}, journal = {Environmental microbiology}, volume = {21}, number = {4}, pages = {1241-1254}, doi = {10.1111/1462-2920.14557}, pmid = {30735001}, issn = {1462-2920}, support = {//NWO-FAPESP/ ; NWO-729.004.003//Netherlands Organization for Scientific Research/ ; FAPESP-2013/50365-5)//Sao Paulo State foundation/ ; }, abstract = {The nitrification inhibitors (NIs) 3,4-dimethylpyrazole (DMPP) and dicyandiamide (DCD) can effectively reduce N2 O emissions; however, which species are targeted and the effect of these NIs on the microbial nitrifier community is still unclear. Here, we identified the ammonia oxidizing bacteria (AOB) species linked to N2 O emissions and evaluated the effects of urea and urea with DCD and DMPP on the nitrifying community in a 258 day field experiment under sugarcane. Using an amoA AOB amplicon sequencing approach and mining a previous dataset of 16S rRNA sequences, we characterized the most likely N2 O-producing AOB as a Nitrosospira spp. and identified Nitrosospira (AOB), Nitrososphaera (archaeal ammonia oxidizer) and Nitrospira (nitrite-oxidizer) as the most abundant, present nitrifiers. The fertilizer treatments had no effect on the alpha and beta diversities of the AOB communities. Interestingly, we found three clusters of co-varying variables with nitrifier operational taxonomic units (OTUs): the N2 O-producing AOB Nitrosospira with N2 O, NO3- , NH4+ , water-filled pore space (WFPS) and pH; AOA Nitrososphaera with NO3- , NH4+ and pH; and AOA Nitrososphaera and NOB Nitrospira with NH4+ , which suggests different drivers. These results support the co-occurrence of non-N2 O-producing Nitrososphaera and Nitrospira in the unfertilized soils and the promotion of N2 O-producing Nitrosospira under urea fertilization. Further, we suggest that DMPP is a more effective NI than DCD in tropical soil under sugarcane.}, }
@article {pmid30729265, year = {2019}, author = {Bernard, C and Escalas, A and Villeriot, N and Agogué, H and Hugoni, M and Duval, C and Carré, C and Got, P and Sarazin, G and Jézéquel, D and Leboulanger, C and Grossi, V and Ader, M and Troussellier, M}, title = {Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta).}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01332-8}, pmid = {30729265}, issn = {1432-184X}, support = {ANR-13-BS06-0001//Agence Nationale de la Recherche/ ; }, abstract = {Lake Dziani Dzaha (Mayotte Island, Indian Ocean) is a tropical thalassohaline lake which geochemical and biological conditions make it a unique aquatic ecosystem considered as a modern analogue of Precambrian environments. In the present study, we focused on the diversity of phytoplanktonic communities, which produce very high and stable biomass (mean2014-2015 = 652 ± 179 μg chlorophyll a L-1). As predicted by classical community ecology paradigms, and as observed in similar environments, a single species is expected to dominate the phytoplanktonic communities. To test this hypothesis, we sampled water column in the deepest part of the lake (18 m) during rainy and dry seasons for two consecutive years. Phytoplanktonic communities were characterized using a combination of metagenomic, microscopy-based and flow cytometry approaches, and we used statistical modeling to identify the environmental factors determining the abundance of dominant organisms. As hypothesized, the overall diversity of the phytoplanktonic communities was very low (15 OTUs), but we observed a co-dominance of two, and not only one, OTUs, viz., Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). We observed a decrease in the abundance of these co-dominant taxa along the depth profile and identified the adverse environmental factors driving this decline. The functional traits measured on isolated strains of these two taxa (i.e., size, pigment composition, and concentration) are then compared and discussed to explain their capacity to cope with the extreme environmental conditions encountered in the aphotic, anoxic, and sulfidic layers of the water column of Lake Dziani Dzaha.}, }
@article {pmid30728279, year = {2019}, author = {Props, R and Monsieurs, P and Vandamme, P and Leys, N and Denef, VJ and Boon, N}, title = {Gene Expansion and Positive Selection as Bacterial Adaptations to Oligotrophic Conditions.}, journal = {mSphere}, volume = {4}, number = {1}, pages = {}, doi = {10.1128/mSphereDirect.00011-19}, pmid = {30728279}, issn = {2379-5042}, mesh = {Adaptation, Physiological/*genetics ; Carbon/metabolism ; Comamonadaceae/*classification/genetics/metabolism ; DNA, Bacterial/genetics ; Fresh Water/chemistry/microbiology ; *Genome, Bacterial ; Genomics ; Metagenomics ; Nuclear Reactors ; Phosphorus/metabolism ; Phylogeny ; *Selection, Genetic ; }, abstract = {We examined the genomic adaptations of prevalent bacterial taxa in a highly nutrient- and ion-depleted freshwater environment located in the secondary cooling water system of a nuclear research reactor. Using genome-centric metagenomics, we found that none of the prevalent bacterial taxa were related to typical freshwater bacterial lineages. We also did not identify strong signatures of genome streamlining, which has been shown to be one of the ecoevolutionary forces shaping the genome characteristics of bacterial taxa in nutrient-depleted environments. Instead, focusing on the dominant taxon, a novel Ramlibacter sp. which we propose to name Ramlibacter aquaticus, we detected extensive positive selection on genes involved in phosphorus and carbon scavenging pathways. These genes were involved in the high-affinity phosphate uptake and storage into polyphosphate granules, metabolism of nitrogen-rich organic matter, and carbon/energy storage into polyhydroxyalkanoate. In parallel, comparative genomics revealed a high number of paralogs and an accessory genome significantly enriched in environmental sensing pathways (i.e., chemotaxis and motility), suggesting extensive gene expansions in R. aquaticus The type strain of R. aquaticus (LMG 30558T) displayed optimal growth kinetics and productivity at low nutrient concentrations, as well as substantial cell size plasticity. Our findings with R. aquaticus LMG 30558T demonstrate that positive selection and gene expansions may represent successful adaptive strategies to oligotrophic environments that preserve high growth rates and cellular productivity.IMPORTANCE By combining a genome-centric metagenomic approach with a culture-based approach, we investigated the genomic adaptations of prevalent populations in an engineered oligotrophic freshwater system. We found evidence for widespread positive selection on genes involved in phosphorus and carbon scavenging pathways and for gene expansions in motility and environmental sensing to be important genomic adaptations of the abundant taxon in this system. In addition, microscopic and flow cytometric analysis of the first freshwater representative of this population (Ramlibacter aquaticus LMG 30558T) demonstrated phenotypic plasticity, possibly due to the metabolic versatility granted by its larger genome, to be a strategy to cope with nutrient limitation. Our study clearly demonstrates the need for the use of a broad set of genomic tools combined with culture-based physiological characterization assays to investigate and validate genomic adaptations.}, }
@article {pmid30726948, year = {2019}, author = {Achouak, W and Abrouk, D and Guyonnet, J and Barakat, M and Ortet, P and Simon, L and Lerondelle, C and Heulin, T and Haichar, FEZ}, title = {Plant hosts control microbial denitrification activity.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {3}, pages = {}, doi = {10.1093/femsec/fiz021}, pmid = {30726948}, issn = {1574-6941}, abstract = {In the rhizosphere, complex and dynamic interactions occur between plants and microbial networks that are primarily mediated by root exudation. Plants exude various metabolites that may influence the rhizosphere microbiota. However, few studies have sought to understand the role of root exudation in shaping the functional capacities of the microbiota. In this study, we aimed to determine the impact of plants on the diversity of active microbiota and their ability to denitrify via root exudates. For that purpose, we grew four plant species, Triticum aestivum, Brassica napus, Medicago truncatula and Arabidopsis thaliana separately in the same soil. We extracted RNA from the root-adhering soil and the root tissues, and we analysed the bacterial diversity by using 16S rRNA metabarcoding. We measured denitrification activity and denitrification gene expression (nirK and nirS) from each root-adhering soil sample and the root tissues using gas chromatography and quantitative PCR, respectively. We demonstrated that plant species shape denitrification activity and modulate the diversity of the active microbiota through root exudation. We observed a positive effect of T. aestivum and A. thaliana on denitrification activity and nirK gene expression on the root systems. Together, our results underscore the potential power of host plants in controlling microbial activities.}, }
@article {pmid30726571, year = {2019}, author = {Laforest-Lapointe, I and Whitaker, BK}, title = {Decrypting the phyllosphere microbiota: progress and challenges.}, journal = {American journal of botany}, volume = {106}, number = {2}, pages = {171-173}, doi = {10.1002/ajb2.1229}, pmid = {30726571}, issn = {1537-2197}, }
@article {pmid30725170, year = {2019}, author = {Sun, X and Li, B and Han, F and Xiao, E and Xiao, T and Sun, W}, title = {Impacts of Arsenic and Antimony Co-Contamination on Sedimentary Microbial Communities in Rivers with Different Pollution Gradients.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01327-5}, pmid = {30725170}, issn = {1432-184X}, support = {41771301//National Natural Science Foundation of China/ ; 41420104007//National Natural Science Foundation of China/ ; }, abstract = {Arsenic (As) and antimony (Sb) are both toxic metalloids that are of primary concern for human health. Mining activity has introduced elevated levels of arsenic and antimony into the rivers and has increased the risks of drinking water contamination in China. Due to their mobility, the majority of the metalloids originating from mining activities are deposited in the river sediments. Thus, depending on various geochemical conditions, sediment could either be a sink or source for As and Sb in the water column. Microbes are key mediators for biogeochemical transformation and can both mobilize or precipitate As and Sb. To further understand the microbial community responses to As and Sb contamination, sediment samples with different contamination levels were collected from three rivers. The result of the study suggested that the major portions of As and Sb were in strong association with the sediment matrix and considered nonbioavailable. These fractions, however, were also suggested to have profound influences on the microbial community composition. As and Sb contamination caused strong reductions in microbial diversity in the heavily contaminated river sediments. Microorganisms were more sensitive to As comparing to Sb, as revealed by the co-occurrence network and random forest predictions. Operational taxonomic units (OTUs) that were potentially involved in As and Sb metabolism, such as Anaerolinea, Sphingomonas, and Opitutus, were enriched in the heavily contaminated samples. In contrast, many keystone taxa, including members of the Hyphomicrobiaceae and Bradyrhizobiaceae families, were inhibited by metalloid contamination, which could further impair crucial environmental services provided by these members.}, }
@article {pmid30724437, year = {2019}, author = {Ma, Y and Zilles, JL and Kent, AD}, title = {An evaluation of primers for detecting denitrifiers via their functional genes.}, journal = {Environmental microbiology}, volume = {21}, number = {4}, pages = {1196-1210}, doi = {10.1111/1462-2920.14555}, pmid = {30724437}, issn = {1462-2920}, support = {//U.S. Department of Agriculture/ ; 2015-67019-23584//National Institute of Food and Agriculture/ ; }, abstract = {Microbial populations provide nitrogen cycling ecosystem services at the nexus of agriculture, environmental quality and climate change. Denitrification, in particular, impacts socio-environmental systems in both positive and negative ways, through reduction of aquatic and atmospheric nitrogen pollution, but also reduction of soil fertility and production of greenhouse gases. However, denitrification rates are quite variable in time and space, and therefore difficult to model. Microbial ecology is working to improve the predictive ecology of denitrifiers by quantifying and describing the diversity of microbial functional groups. However, metagenomic sequencing has revealed previously undescribed diversity within these functional groups, and highlighted a need to reevaluate coverage of existing DNA primers for denitrification functional genes. We provide here a comprehensive in silico evaluation of primer sets that target diagnostic genes in the denitrification pathway. This analysis makes use of current DNA sequence data available for each functional gene. It contributes a comparative analysis of the strengths and limitations of each primer set for describing denitrifier functional groups. This analysis identifies genes for which development of new tools is needed, and aids in interpretation of existing datasets, both of which will facilitate application of molecular methods to further develop the predictive ecology of denitrifiers.}, }
@article {pmid30721227, year = {2019}, author = {Marsland, R and Cui, W and Goldford, J and Sanchez, A and Korolev, K and Mehta, P}, title = {Available energy fluxes drive a transition in the diversity, stability, and functional structure of microbial communities.}, journal = {PLoS computational biology}, volume = {15}, number = {2}, pages = {e1006793}, doi = {10.1371/journal.pcbi.1006793}, pmid = {30721227}, issn = {1553-7358}, support = {R35 GM119461/GM/NIGMS NIH HHS/United States ; }, mesh = {Computational Biology ; Databases, Factual ; *Ecosystem ; Energy Metabolism/*physiology ; Microbial Consortia/*physiology ; Models, Biological ; Stochastic Processes ; Thermodynamics ; }, abstract = {A fundamental goal of microbial ecology is to understand what determines the diversity, stability, and structure of microbial ecosystems. The microbial context poses special conceptual challenges because of the strong mutual influences between the microbes and their chemical environment through the consumption and production of metabolites. By analyzing a generalized consumer resource model that explicitly includes cross-feeding, stochastic colonization, and thermodynamics, we show that complex microbial communities generically exhibit a transition as a function of available energy fluxes from a &quot;resource-limited&quot; regime where community structure and stability is shaped by energetic and metabolic considerations to a diverse regime where the dominant force shaping microbial communities is the overlap between species' consumption preferences. These two regimes have distinct species abundance patterns, different functional profiles, and respond differently to environmental perturbations. Our model reproduces large-scale ecological patterns observed across multiple experimental settings such as nestedness and differential beta diversity patterns along energy gradients. We discuss the experimental implications of our results and possible connections with disorder-induced phase transitions in statistical physics.}, }
@article {pmid30719551, year = {2019}, author = {Margesin, R and Collins, T}, title = {Microbial ecology of the cryosphere (glacial and permafrost habitats): current knowledge.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {6}, pages = {2537-2549}, doi = {10.1007/s00253-019-09631-3}, pmid = {30719551}, issn = {1432-0614}, support = {IF/01635/2014//Investigador FCT Programme/ ; }, abstract = {Microorganisms in cold ecosystems play a key ecological role in their natural habitats. Since these ecosystems are especially sensitive to climate changes, as indicated by the worldwide retreat of glaciers and ice sheets as well as permafrost thawing, an understanding of the role and potential of microbial life in these habitats has become crucial. Emerging technologies have added significantly to our knowledge of abundance, functional activity, and lifestyles of microbial communities in cold environments. The current knowledge of microbial ecology in glacial habitats and permafrost, the most studied habitats of the cryosphere, is reported in this review.}, }
@article {pmid30715579, year = {2019}, author = {Kivlin, SN and Kazenel, MR and Lynn, JS and Lee Taylor, D and Rudgers, JA}, title = {Plant Identity Influences Foliar Fungal Symbionts More Than Elevation in the Colorado Rocky Mountains.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01336-4}, pmid = {30715579}, issn = {1432-184X}, support = {DEB1354972//Directorate for Biological Sciences/ ; }, abstract = {Despite colonizing nearly every plant on Earth, foliar fungal symbionts have received little attention in studies on the biogeography of host-associated microbes. Evidence from regional scale studies suggests that foliar fungal symbiont distributions are influenced both by plant hosts and environmental variation in climate and soil resources. However, previous surveys have focused on either one plant host across an environmental gradient or one gradient and multiple plant hosts, making it difficult to disentangle the influence of host identity from the influence of the environment on foliar endophyte communities. We used a culture-based approach to survey fungal symbiont composition in the leaves of nine C3 grass species along replicated elevation gradients in grasslands of the Colorado Rocky Mountains. In these ecosystems, the taxonomic richness and composition of foliar fungal symbionts were mostly structured by the taxonomic identity of the plant host rather than by variation in climate. Plant traits related to size (height and leaf length) were the best predictors of foliar fungal symbiont composition and diversity, and composition did not vary predictably with plant evolutionary history. The largest plants had the most diverse and distinctive fungal communities. These results suggest that across the ~ 300 m elevation range that we sampled, foliar fungal symbionts may indirectly experience climate change by tracking the shifting distributions of plant hosts rather than tracking climate directly.}, }
@article {pmid30715272, year = {2019}, author = {McAllister, SM and Moore, RM and Gartman, A and Luther, GW and Emerson, D and Chan, CS}, title = {The Fe(II)-oxidizing Zetaproteobacteria: historical, ecological and genomic perspectives.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {4}, pages = {}, doi = {10.1093/femsec/fiz015}, pmid = {30715272}, issn = {1574-6941}, abstract = {The Zetaproteobacteria are a class of bacteria typically associated with marine Fe(II)-oxidizing environments. First discovered in the hydrothermal vents at Loihi Seamount, Hawaii, they have become model organisms for marine microbial Fe(II) oxidation. In addition to deep sea and shallow hydrothermal vents, Zetaproteobacteria are found in coastal sediments, other marine subsurface environments, steel corrosion biofilms and saline terrestrial springs. Isolates from a range of environments all grow by autotrophic Fe(II) oxidation. Their success lies partly in their microaerophily, which enables them to compete with abiotic Fe(II) oxidation at Fe(II)-rich oxic/anoxic transition zones. To determine the known diversity of the Zetaproteobacteria, we have used 16S rRNA gene sequences to define 59 operational taxonomic units (OTUs), at 97% similarity. While some Zetaproteobacteria taxa appear to be cosmopolitan, others are enriched by specific habitats. OTU networks show that certain Zetaproteobacteria co-exist, sharing compatible niches. These niches may correspond with adaptations to O2, H2 and nitrate availability, based on genomic analyses of metabolic potential. Also, a putative Fe(II) oxidation gene has been found in diverse Zetaproteobacteria taxa, suggesting that the Zetaproteobacteria evolved as Fe(II) oxidation specialists. In all, studies suggest that Zetaproteobacteria are widespread, and therefore may have a broad influence on marine and saline terrestrial Fe cycling.}, }
@article {pmid30712793, year = {2019}, author = {Raabis, S and Li, W and Cersosimo, L}, title = {Effects and immune responses of probiotic treatment in ruminants.}, journal = {Veterinary immunology and immunopathology}, volume = {208}, number = {}, pages = {58-66}, doi = {10.1016/j.vetimm.2018.12.006}, pmid = {30712793}, issn = {1873-2534}, support = {T32 OD010423/OD/NIH HHS/United States ; }, mesh = {Animals ; Cell Line ; Gastrointestinal Microbiome/immunology ; Gastrointestinal Tract/immunology ; Immunity, Innate ; Probiotics/*therapeutic use ; Ruminants/*immunology/*microbiology ; }, abstract = {Gut microbial colonization and establishment are vital to ruminant health and production. This review article focuses on current knowledge and methods used to understand and manipulate the gut microbial community in ruminant animals, with a special focus on probiotics treatment. This review highlights the most promising of studies in this area, including gut microbial colonization and establishment, effect of gastrointestinal tract microbial community on host mucosal innate immune function, impact of feeding strategies on gut microbial community, current probiotic treatments in ruminants, methods to manipulate the gut microbiota and associated antimicrobial compounds, and models and cell lines used in understanding the host immune response to probiotic treatments. As a lot of work in this area was done in humans and mice, this review article also includes up-to-date knowledge from relevant studies in human and mouse models. This review is a useful resource for scientists working in the areas of ruminant nutrition and health, and to researchers investigating the microbial ecology and its relation to animal health.}, }
@article {pmid30706113, year = {2019}, author = {Ávila, MP and Oliveira-Junior, ES and Reis, MP and Hester, ER and Diamantino, C and Veraart, AJ and Lamers, LPM and Kosten, S and Nascimento, AMA}, title = {The Water Hyacinth Microbiome: Link Between Carbon Turnover and Nutrient Cycling.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01331-9}, pmid = {30706113}, issn = {1432-184X}, support = {APQ 01673/16//Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais/ ; 306774/2016-0//Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (BR)/ ; BEX 13607/13-8//Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior/ ; 8631(2012)//Boeing/ ; 2017//Erasmus plus program/ ; }, abstract = {Water hyacinth (WH), a large floating plant, plays an important role in the biogeochemistry and ecology of many freshwaters globally. Its biogeochemical impact on wetland functioning is strongly mediated by the microbiome associated with its roots. However, little is known about the structure and function of this WH rhizobiome and its relation to wetland ecosystem functioning. Here, we unveil the core and transient rhizobiomes of WH and their key biogeochemical functions in two of the world's largest wetlands: the Amazon and the Pantanal. WH hosts a highly diverse microbial community shaped by spatiotemporal changes. Proteobacteria lineages were most common, followed by Actinobacteria and Planctomycetes. Deltaproteobacteria and Sphingobacteriia predominated in the core microbiome, potentially associated with polysaccharide degradation and fermentation of plant-derived carbon. Conversely, a plethora of lineages were transient, including highly abundant Acinetobacter, Acidobacteria subgroup 6, and methanotrophs, thus assuring diverse taxonomic signatures in the two different wetlands. Our findings point out that methanogenesis is a key driver of, and proxy for, community structure, especially during seasonal plant decline. We provide ecologically relevant insights into the WH microbiome, which is a key element linking plant-associated carbon turnover with other biogeochemical fluxes in tropical wetlands.}, }
@article {pmid30706112, year = {2019}, author = {Song, Y and Mao, G and Gao, G and Bartlam, M and Wang, Y}, title = {Structural and Functional Changes of Groundwater Bacterial Community During Temperature and pH Disturbances.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01333-7}, pmid = {30706112}, issn = {1432-184X}, support = {No.31670498 and 31322012//National Natural Science Foundation of China/ ; }, abstract = {In this study, we report the characteristics of a microbial community in sampled groundwater and elucidate the effects of temperature and pH disturbances on bacterial structure and nitrogen-cycling functions. The predominant phyla of candidate OD1, candidate OP3, and Proteobacteria represented more than half of the total bacteria, which clearly manifested as a &quot;low nucleic acid content (LNA) bacteria majority&quot; type via flow cytometric fingerprint. The results showed that LNA bacteria were more tolerant to rapid changes in temperature and pH, compared to high nucleic acid content (HNA) bacteria. A continuous temperature increase test demonstrated that the LNA bacterial group was less competitive than the HNA bacterial group in terms of maintaining their cell intactness and growth potential. In contrast, the percentage of intact LNA bacteria was maintained at nearly 70% with pH decrease, despite a 50% decrease in total intact cells. Next-generation sequencing results revealed strong resistance and growth potential of phylum Proteobacteria when the temperature increased or the pH decreased in groundwater, especially for subclasses α-, β-, and γ-Proteobacteria. In addition, relative abundance of nitrogen-related functional genes by qPCR showed no difference in nitrifiers or denitrifiers within 0.45 μm-captured and 0.45 μm-filterable bacteria due to phylogenetic diversity. One exception was the monophyletic anammox bacteria that belong to the phylum Planctomycetes, which were mostly captured on a 0.45-μm filter. Furthermore, we showed that both temperature increase and pH decrease could enhance the denitrification potential, whereas the nitrification and anammox potentials were weakened.}, }
@article {pmid30704595, year = {2019}, author = {Kamimura, BA and De Filippis, F and Sant'Ana, AS and Ercolini, D}, title = {Large-scale mapping of microbial diversity in artisanal Brazilian cheeses.}, journal = {Food microbiology}, volume = {80}, number = {}, pages = {40-49}, doi = {10.1016/j.fm.2018.12.014}, pmid = {30704595}, issn = {1095-9998}, mesh = {Animals ; *Biodiversity ; Brazil ; Cheese/*microbiology ; Cluster Analysis ; DNA, Bacterial/genetics ; *Food Microbiology ; Geography ; Microbiota/*genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {Brazilian artisanal cheeses are characterized by the use of raw milk and in some cases, natural starter cultures, known as &quot;pingo&quot;, as well as following simple and traditional manufacturing technology. In this study, a large-scale screening of the microbial ecology of 11 different types of artisanal cheeses produced in five geographical areas of Brazil was performed. Besides, the specific origin-related microbial signatures were identified. Clear geography- and technology-based differences in the microbiota were observed. Lactic acid bacteria dominated in all cheeses although Enterobacteriaceae and Staphylococcus also occurred in North, Northeast and Central cheeses. Differences in the lactic acid bacteria patterns were also highlighted: Streptococcus, Leuconostoc, Lactococcus and Lactobacillus were differently combined in terms of relative abundance according to product type and region of production. This study provides a comprehensive, unprecedented microbiological mapping of Brazilian cheeses, highlighting the impact of geographical origin and mode of production on microbial diversity. The results obtained will help to plan an evaluation of microbial contamination sources that will need to be studied for the improvement of cheese quality and safety.}, }
@article {pmid30701285, year = {2019}, author = {Ely, CS and Smets, BF}, title = {Guild Composition of Root-Associated Bacteria Changes with Increased Soil Contamination.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01326-6}, pmid = {30701285}, issn = {1432-184X}, support = {R829405//U.S. Environmental Protection Agency/ ; }, abstract = {The interaction of plants and root-associated bacteria encourage the removal of soil contaminants. Engineers and scientists have looked at this phenomenon as a possible means of soil treatment (rhizodegradation). In this study, root-associated bacteria were isolated and selected for growth on a model soil contaminant: polycyclic aromatic hydrocarbons. Isolates were compared genetically to see how plant-bacteria interactions change with soil contamination levels. Characterization of root-associated bacteria was performed using REP-PCR genetic fingerprinting and 16s rRNA gene alignments for identification. Genomic fingerprinting indicated that the composition of PAH-metabolizing bacteria (&quot;guild&quot;) was similar among plant species at each treatment level. However, guild composition changed with contamination level and differed from that of bulk soils, suggesting a common rhizosphere effect among plant species related to PAH contamination. PAH-metabolizing bacteria were identified through 16s rRNA gene alignment as members of the α-, β-, and γ-proteobacteria, Actinobacteria, and Bacilli classes. Burkholderia and Pseudomonas spp. were the only genera of bacteria isolated from all plant types in uncontaminated controls. Bacterial species found at the highest treatment included Achromobacter xylosoxidans, Rhodococcus spp., members of the Microbacteriae, Stenotrophomonas rhizophilia, as well as other members of the alpha-proteobacteria. Given their ability to grow on PAHs and inhabit highly contaminated rhizospheres, these bacteria appear good candidates for the promotion of rhizodegradation.}, }
@article {pmid30701133, year = {2019}, author = {De Paepe, K and Verspreet, J and Rezaei, MN and Hidalgo Martinez, S and Meysman, F and Van de Walle, D and Dewettinck, K and Raes, J and Courtin, C and Van de Wiele, T}, title = {Isolation of wheat bran-colonizing and metabolizing species from the human fecal microbiota.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6293}, doi = {10.7717/peerj.6293}, pmid = {30701133}, issn = {2167-8359}, abstract = {Undigestible, insoluble food particles, such as wheat bran, are important dietary constituents that serve as a fermentation substrate for the human gut microbiota. The first step in wheat bran fermentation involves the poorly studied solubilization of fibers from the complex insoluble wheat bran structure. Attachment of bacteria has been suggested to promote the efficient hydrolysis of insoluble substrates, but the mechanisms and drivers of this microbial attachment and colonization, as well as subsequent fermentation remain to be elucidated. We have previously shown that an individually dependent subset of gut bacteria is able to colonize the wheat bran residue. Here, we isolated these bran-attached microorganisms, which can then be used to gain mechanistic insights in future pure culture experiments. Four healthy fecal donors were screened to account for inter-individual differences in gut microbiota composition. A combination of a direct plating and enrichment method resulted in the isolation of a phylogenetically diverse set of species, belonging to the Bacteroidetes, Firmicutes, Proteobacteria and Actinobacteria phyla. A comparison with 16S rRNA gene sequences that were found enriched on wheat bran particles in previous studies, however, showed that the isolates do not yet cover the entire diversity of wheat-bran colonizing species, comprising among others a broad range of Prevotella, Bacteroides and Clostridium cluster XIVa species. We, therefore, suggest several modifications to the experiment set-up to further expand the array of isolated species.}, }
@article {pmid30698709, year = {2019}, author = {Janssens, TKS and Tyc, O and Besselink, H and de Boer, W and Garbeva, P}, title = {Biological activities associated with the volatile compound 2,5-bis(1-methylethyl)-pyrazine.}, journal = {FEMS microbiology letters}, volume = {366}, number = {3}, pages = {}, doi = {10.1093/femsle/fnz023}, pmid = {30698709}, issn = {1574-6968}, abstract = {Pyrazines are 1,4-diazabenzene-based volatile organic compounds and known for their broad-spectrum antimicrobial activity. In the present study, we assessed the antimicrobial activity of 2,5-bis(1-methylethyl)-pyrazine, produced by Paenibacillus sp. AD87 during co-culture with Burkholderia sp. AD24. In addition, we were using transcriptional reporter assays in E. coli and mammalian cells to decipher the possible mode of action. Bacterial and mammalian luciferase reporter strains were deployed to elucidate antimicrobial and toxicological effects of 2,5-bis(1-methylethyl)-pyrazine. At high levels of exposure, 2,5-bis(1-methylethyl)-pyrazine exerted strong DNA damage response. At lower concentrations, cell-wall damage response was observed. The activity was corroborated by a general toxicity reporter assay in E. coli ΔampD, defective in peptidoglycan turnover. The maximum E. coli cell-wall stress activity was measured at a concentration close to the onset of the mammalian cytotoxicity, while other adverse outcome pathways, such as the activation of aryl hydrocarbon and estrogenic receptor, the p53 tumour suppressor and the oxidative stress-related Nrf2 transcription factor, were induced at elevated concentrations compared to the response of mammalian cells. Because of its broad-spectrum antimicrobial activity at lower concentrations and the relatively low mammalian toxicity, 2,5-bis(1-methylethyl)-pyrazine is a potential bio-based fumigant with possible applications in food industry, agriculture or logistics.}, }
@article {pmid30697889, year = {2019}, author = {Eckert, EM and Quero, GM and Di Cesare, A and Manfredini, G and Mapelli, F and Borin, S and Fontaneto, D and Luna, GM and Corno, G}, title = {Antibiotic disturbance affects aquatic microbial community composition and food web interactions but not community resilience.}, journal = {Molecular ecology}, volume = {28}, number = {5}, pages = {1170-1182}, doi = {10.1111/mec.15033}, pmid = {30697889}, issn = {1365-294X}, support = {Call 2014 - Molecular Biodiversity of invasive spe//LifeWatch-Italy/International ; 655537//Marie Skłodowska-Curie Actions Individual Fellowship/International ; Program 2013-15//CIPAIS - International Commission for the Protection of Italian-Swiss Waters/International ; 655537//Horizon 2020/International ; 2015//Horizon 2020/International ; 2017//Horizon 2020/International ; 2//Horizon 2020/International ; }, abstract = {Notwithstanding the fundamental role that environmental microbes play for ecosystem functioning, data on how microbes react to disturbances are still scarce, and most factors that confer stability to microbial communities are unknown. In this context, antibiotic discharge into the environment is considered a worldwide threat for ecosystems with potential risks to human health. We therefore tested resilience of microbial communities challenged by the presence of an antibiotic. In a continuous culture experiment, we compared the abundance, composition and diversity of microbial communities undisturbed or disturbed by the constant addiction of tetracycline in low (10 µg/L) or intermediate (100 µg/L) concentration (press disturbance). Further, the bacterial communities in the three treatments had to face the sudden pulse disturbance of adding an allochthonous bacterium (Escherichia coli). Tetracycline, even at low concentrations, affected microbial communities by changing their phylogenetic composition and causing cell aggregation. This, however, did not coincide with a reduced microbial diversity, but was mainly caused by a shift in dominance of specific bacterial families. Moreover, the less disturbed community (10 µg/L tetracycline) was sometimes more similar to the control and sometimes more similar to heavily disturbed community (100 µg/L tetracycline). All in all, we could not see a pattern where the communities disturbed with antibiotics were less resilient to a second disturbance introducing E. coli, but they seemed to be able to buffer the input of the allochthonous strain in a similar manner as the control.}, }
@article {pmid30694508, year = {2019}, author = {Pérez-Cobas, AE and Buchrieser, C}, title = {Analysis of the Pulmonary Microbiome Composition of Legionella pneumophila-Infected Patients.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1921}, number = {}, pages = {429-443}, doi = {10.1007/978-1-4939-9048-1_27}, pmid = {30694508}, issn = {1940-6029}, abstract = {The analysis of the lung microbiome composition is a field of research that recently emerged. It gained great interest in pulmonary diseases such as pneumonia since the microbiome seems to be involved in host immune responses, inflammation, and protection against pathogens. Thus, it is possible that the microbial communities living in the lungs play a role in the outcome and severity of lung infections such as Legionella-caused pneumonia and in the response to antibiotic therapy. In this chapter, all steps necessary for the characterization of the bacterial and fungal fraction of the lung microbiome using high-throughput sequencing approaches are explained, starting from the selection of clinical samples to the analysis of the taxonomic composition, diversity, and ecology of the microbiome.}, }
@article {pmid30694341, year = {2019}, author = {Ruiz-Ripa, L and Gómez, P and Alonso, CA and Camacho, MC and de la Puente, J and Fernández-Fernández, R and Ramiro, Y and Quevedo, MA and Blanco, JM and Zarazaga, M and Höfle, U and Torres, C}, title = {Detection of MRSA of Lineages CC130-mecC and CC398-mecA and Staphylococcus delphini-lnu(A) in Magpies and Cinereous Vultures in Spain.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01328-4}, pmid = {30694341}, issn = {1432-184X}, support = {SAF2016-76571-R//Ministerio de Econom?a, Industria y Competitividad, Gobierno de Espa?a/ ; }, abstract = {The aim of this study was to determine the carriage rate of coagulase-positive staphylococci (CoPS) in wild birds and to characterize recovered isolates. Tracheal samples from 324 wild birds, obtained in different Spanish regions during 2015-2016, were screened for CoPS carriage. The antimicrobial resistance profile and the virulence gene content were investigated. Molecular typing was performed by spa, agr, MLST, SCCmec, and S. delphini group classification. CoPS were recovered from 26 samples of wild birds (8.3%), and 27 isolates were further characterized. Two CoPS species were detected: S. aureus (n = 15; eight cinereous vultures and seven magpies) and S. delphini (n = 12; 11 cinereous vultures and one red kite). Thirteen S. aureus were methicillin-resistant (MRSA) and the remaining two strains were methicillin-susceptible (MSSA). Twelve MRSA were mecC-positive, typed as t843-ST1583/ST1945/ST1581/ST1571 (n = 11) and t1535-ST1945 (n = 1) (all of clonal-complex CC130); they were susceptible to the non-β-lactams tested. The remaining MRSA strain carried the mecA gene, was typed as t011-ST398-CC398-agrI-SCCmec-V, and showed a multiresistance phenotype. MSSA isolates were ascribed to lineages ST97-CC97 and ST425-CC425. All S. aureus lacked the studied virulence genes (lukS/F-PV, tst, eta, etb, and etd), and the IEC type E (with scn and sak genes) was detected in four mecC-positive and one MSSA isolates. S. delphini strains were methicillin-susceptible but showed resistance to at least one of the antimicrobials tested, with high penicillin (75%, with blaZ gene) and tetracycline [58%, with tet(K)± tet(L)] resistance rates. All S. delphini isolates presented the virulence genes lukS-I, siet, and se-int, and four carried the clindamycin-resistance lnu(A) gene.}, }
@article {pmid30689848, year = {2019}, author = {Xu, CQ and Liu, H and Zhou, SS and Zhang, DX and Zhao, W and Wang, S and Chen, F and Sun, YQ and Nie, S and Jia, KH and Jiao, SQ and Zhang, RG and Yun, QZ and Guan, W and Wang, X and Gao, Q and Bennetzen, JL and Maghuly, F and Porth, I and Van de Peer, Y and Wang, XR and Ma, Y and Mao, JF}, title = {Genome sequence of Malania oleifera, a tree with great value for nervonic acid production.}, journal = {GigaScience}, volume = {8}, number = {2}, pages = {}, doi = {10.1093/gigascience/giy164}, pmid = {30689848}, issn = {2047-217X}, abstract = {BACKGROUND: Malania oleifera, a member of the Olacaceae family, is an IUCN red listed tree, endemic and restricted to the Karst region of southwest China. This tree's seed is valued for its high content of precious fatty acids (especially nervonic acid). However, studies on its genetic makeup and fatty acid biogenesis are severely hampered by a lack of molecular and genetic tools.<br><br>FINDINGS: We generated 51 Gb and 135 Gb of raw DNA sequences, using Pacific Biosciences (PacBio) single-molecule real-time and 10× Genomics sequencing, respectively. A final genome assembly, with a scaffold N50 size of 4.65 Mb and a total length of 1.51 Gb, was obtained by primary assembly based on PacBio long reads plus scaffolding with 10× Genomics reads. Identified repeats constituted ∼82% of the genome, and 24,064 protein-coding genes were predicted with high support. The genome has low heterozygosity and shows no evidence for recent whole genome duplication. Metabolic pathway genes relating to the accumulation of long-chain fatty acid were identified and studied in detail.<br><br>CONCLUSIONS: Here, we provide the first genome assembly and gene annotation for M. oleifera. The availability of these resources will be of great importance for conservation biology and for the functional genomics of nervonic acid biosynthesis.}, }
@article {pmid30689307, year = {2019}, author = {Wackett, LP}, title = {Evolutionary microbial ecology: An annotated selection of World Wide Web sites relevant to the topics in environmental microbiology.}, journal = {Environmental microbiology reports}, volume = {11}, number = {1}, pages = {48-49}, doi = {10.1111/1758-2229.12734}, pmid = {30689307}, issn = {1758-2229}, mesh = {*Biological Evolution ; Databases, Factual ; *Environmental Microbiology ; *Internet ; }, }
@article {pmid30689286, year = {2019}, author = {Berg, JS and Pjevac, P and Sommer, T and Buckner, CRT and Philippi, M and Hach, PF and Liebeke, M and Holtappels, M and Danza, F and Tonolla, M and Sengupta, A and Schubert, CJ and Milucka, J and Kuypers, MMM}, title = {Dark aerobic sulfide oxidation by anoxygenic phototrophs in anoxic waters.}, journal = {Environmental microbiology}, volume = {21}, number = {5}, pages = {1611-1626}, doi = {10.1111/1462-2920.14543}, pmid = {30689286}, issn = {1462-2920}, support = {//Deutsche Forschungsgemeinschaft/ ; Cross Disciplinary Fellowship, LT000993/2014-C//Human Frontier Science Program/ ; //International Max Planck Research School of Marine Microbiology/ ; //Max Planck Society/ ; }, abstract = {Anoxygenic phototrophic sulfide oxidation by green and purple sulfur bacteria (PSB) plays a key role in sulfide removal from anoxic shallow sediments and stratified waters. Although some PSB can also oxidize sulfide with nitrate and oxygen, little is known about the prevalence of this chemolithotrophic lifestyle in the environment. In this study, we investigated the role of these phototrophs in light-independent sulfide removal in the chemocline of Lake Cadagno. Our temporally resolved, high-resolution chemical profiles indicated that dark sulfide oxidation was coupled to high oxygen consumption rates of ~9 μM O2 ·h-1 . Single-cell analyses of lake water incubated with 13 CO2 in the dark revealed that Chromatium okenii was to a large extent responsible for aerobic sulfide oxidation and it accounted for up to 40% of total dark carbon fixation. The genome of Chr. okenii reconstructed from the Lake Cadagno metagenome confirms its capacity for microaerophilic growth and provides further insights into its metabolic capabilities. Moreover, our genomic and single-cell data indicated that other PSB grow microaerobically in these apparently anoxic waters. Altogether, our observations suggest that aerobic respiration may not only play an underappreciated role in anoxic environments but also that organisms typically considered strict anaerobes may be involved.}, }
@article {pmid30687882, year = {2019}, author = {Liu, J and Tu, T and Gao, G and Bartlam, M and Wang, Y}, title = {Biogeography and Diversity of Freshwater Bacteria on a River Catchment Scale.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01323-9}, pmid = {30687882}, issn = {1432-184X}, support = {2015CB459000//Ministry of Science and Technology of the People's Republic of China/ ; 31670498//National Natural Science Foundation of China/ ; 31322012//National Natural Science Foundation of China/ ; }, abstract = {To illustrate how freshwater bacterial community changes with geographic gradient, we investigated the spatial changes of bacterial abundance and community structures from over 200 samples on a catchment scale in the Songhua River using heterotrophic plate counts, flow cytometry, denaturing gradient gel electrophoresis, and pyrosequencing analysis. The results showed that the mainstream had higher cultivable bacteria and total bacterial concentration than tributaries in the Songhua River catchment. Response model analysis demonstrated that the bacterial community exhibits a biogeographical signature even in an interconnected river network system, and the total bacterial concentration and biodiversity were significantly correlated to latitude (p < 0.001) and longitude (p < 0.001). Multivariate redundancy analysis indicated that temperature was the most important factor driving bacterial community structure in the Songhua River, which accounts for 35.30% variance of communities, then dissolved oxygen (17.60%), latitude (17.60%), longitude (11.80%), and pH (5.88%). High-throughput pyrosequencing revealed that at the phylum level, Proteobacteria was numerically dominant (89.6%) in river catchment, followed by Bacteroidetes (8.1%) and Cyanobacteria (1.2%). The overall results revealed that the bacterial community was driven by geographical distance regardless of the continuum of the river on a catchment scale.}, }
@article {pmid30687755, year = {2018}, author = {Kuang, X and Chen, V and Xu, X}, title = {Novel Approaches to the Control of Oral Microbial Biofilms.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {6498932}, doi = {10.1155/2018/6498932}, pmid = {30687755}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/*therapeutic use ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Dental Cements/pharmacology/therapeutic use ; Humans ; Mouth/*microbiology ; Virulence/drug effects ; }, abstract = {Effective management of biofilm-related oral infectious diseases is a global challenge. Oral biofilm presents increased resistance to antimicrobial agents and elevated virulence compared with planktonic bacteria. Antimicrobial agents, such as chlorhexidine, have proven effective in the disruption/inhibition of oral biofilm. However, the challenge of precisely and continuously eliminating the specific pathogens without disturbing the microbial ecology still exists, which is a major factor in determining the virulence of a multispecies microbial consortium and the consequent development of oral infectious diseases. Therefore, several novel approaches are being developed to inhibit biofilm virulence without necessarily inducing microbial dysbiosis of the oral cavity. Nanoparticles, such as pH-responsive enzyme-mimic nanoparticles, have been developed to specifically target the acidic niches within the oral biofilm where tooth demineralization readily occurs, in effect controlling dental caries. Quaternary ammonium salts (QAS) such as dimethylaminododecyl methacrylate (DMADDM), when incorporated into dental adhesives or resin composite, have also shown excellent and durable antimicrobial activity and thus could effectively inhibit the occurrence of secondary caries. In addition, custom-designed small molecules, natural products and their derivatives, as well as basic amino acids such as arginine, have demonstrated ecological effects by modulating the virulence of the oral biofilm without universally killing the commensal bacteria, indicating a promising approach to the management of oral infectious diseases such as dental caries and periodontal diseases. This article aims to introduce these novel approaches that have shown potential in the control of oral biofilm. These methods may be utilized in the near future to effectively promote the clinical management of oral infectious diseases and thus benefit oral health.}, }
@article {pmid30687262, year = {2018}, author = {Zhou, C and Ontiveros-Valencia, A and Nerenberg, R and Tang, Y and Friese, D and Krajmalnik-Brown, R and Rittmann, BE}, title = {Hydrogenotrophic Microbial Reduction of Oxyanions With the Membrane Biofilm Reactor.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3268}, doi = {10.3389/fmicb.2018.03268}, pmid = {30687262}, issn = {1664-302X}, abstract = {Oxyanions, such as nitrate, perchlorate, selenate, and chromate are commonly occurring contaminants in groundwater, as well as municipal, industrial, and mining wastewaters. Microorganism-mediated reduction is an effective means to remove oxyanions from water by transforming oxyanions into harmless and/or immobilized forms. To carry out microbial reduction, bacteria require a source of electrons, called the electron-donor substrate. Compared to organic electron donors, H2 is not toxic, generates minimal secondary contamination, and can be readily obtained in a variety of ways at reasonable cost. However, the application of H2 through conventional delivery methods, such as bubbling, is untenable due to H2's low water solubility and combustibility. In this review, we describe the membrane biofilm reactor (MBfR), which is a technological breakthrough that makes H2 delivery to microorganisms efficient, reliable, and safe. The MBfR features non-porous gas-transfer membranes through which bubbleless H2 is delivered on-demand to a microbial biofilm that develops naturally on the outer surface of the membranes. The membranes serve as an active substratum for a microbial biofilm able to biologically reduce oxyanions in the water. We review the development of the MBfR technology from bench, to pilot, and to commercial scales, and we elucidate the mechanisms that control MBfR performance, particularly including methods for managing the biofilm's structure and function. We also give examples of MBfR performance for cases of treating single and co-occurring oxyanions in different types of contaminated water. In summary, the MBfR is an effective and reliable technology for removing oxyanion contaminants by accurately providing a biofilm with bubbleless H2 on demand. Controlling the H2 supply in accordance to oxyanion surface loading and managing the accumulation and activity of biofilm are the keys for process success.}, }
@article {pmid30685711, year = {2019}, author = {Vick, SHW and Greenfield, P and Pinetown, KL and Sherwood, N and Gong, S and Tetu, SG and Midgley, DJ and Paulsen, IT}, title = {Succession Patterns and Physical Niche Partitioning in Microbial Communities from Subsurface Coal Seams.}, journal = {iScience}, volume = {12}, number = {}, pages = {152-167}, doi = {10.1016/j.isci.2019.01.011}, pmid = {30685711}, issn = {2589-0042}, abstract = {The subsurface represents a largely unexplored frontier in microbiology. Here, coal seams present something of an oasis for microbial life, providing moisture, warmth, and abundant fossilized organic material. Microbes in coal seams are thought to syntrophically mobilize fossilized carbon from the geosphere to the biosphere. Despite the environmental and economic importance of this process, little is known about the microbial ecology of coal seams. In the current study, ecological succession and spatial niche partitioning are explored in three coal seam microbial communities. Scanning electron microscopic visualization and 16S rRNA sequencing track changes in microbial communities over time, revealing distinct attached and planktonic communities displaying patterns of ecological succession. Attachment to the coal surface is biofilm mediated on Surat coal, whereas microbes on Sydney and Gunnedah coal show different attachment processes. This study demonstrates that coal seam microbial communities undergo spatial niche partitioning during periods of succession as microbes colonize coal environments.}, }
@article {pmid30684803, year = {2019}, author = {Kumar, M and Jaiswal, S and Sodhi, KK and Shree, P and Singh, DK and Agrawal, PK and Shukla, P}, title = {Antibiotics bioremediation: Perspectives on its ecotoxicity and resistance.}, journal = {Environment international}, volume = {124}, number = {}, pages = {448-461}, doi = {10.1016/j.envint.2018.12.065}, pmid = {30684803}, issn = {1873-6750}, abstract = {Antibiotic is one of the most significant discoveries and have brought a revolution in the field of medicine for human therapy. In addition to the medical uses, antibiotics have broad applications in agriculture and animal husbandry. In developing nations, antibiotics use have helped to increase the life expectancy by lowering the deaths due to bacterial infections, but the risks associated with antibiotics pollution is largely affecting people. Since antibiotics are released partially degraded and undegraded into environment creating antibiotic pollution, and its bioremediation is a challenging task. In the present review, we have discussed the primary antibiotic sources like hospitals, dairy, and agriculture causing antibiotic pollution and their innovative detection methods. The strong commitment towards the resistance prevention and participation, nations through strict policies and their implementations now come to fight against the antibiotic resistance under WHO. The review also deciphers the bacterial evolution based strategies to overcome the effects of antibiotics, so the antibiotic degradation and elimination from the environment and its health benefits. The present review focuses on the environmental sources of antibiotics, it's possible degradation mechanisms, health effects, and bacterial antibiotics resistance mechanisms.}, }
@article {pmid30683748, year = {2019}, author = {Burkert, A and Douglas, TA and Waldrop, MP and Mackelprang, R}, title = {Changes in the Active, Dead, and Dormant Microbial Community Structure across a Pleistocene Permafrost Chronosequence.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {7}, pages = {}, doi = {10.1128/AEM.02646-18}, pmid = {30683748}, issn = {1098-5336}, abstract = {Permafrost hosts a community of microorganisms that survive and reproduce for millennia despite extreme environmental conditions, such as water stress, subzero temperatures, high salinity, and low nutrient availability. Many studies focused on permafrost microbial community composition use DNA-based methods, such as metagenomics and 16S rRNA gene sequencing. However, these methods do not distinguish among active, dead, and dormant cells. This is of particular concern in ancient permafrost, where constant subzero temperatures preserve DNA from dead organisms and dormancy may be a common survival strategy. To circumvent this, we applied (i) LIVE/DEAD differential staining coupled with microscopy, (ii) endospore enrichment, and (iii) selective depletion of DNA from dead cells to permafrost microbial communities across a Pleistocene permafrost chronosequence (19,000, 27,000, and 33,000 years old). Cell counts and analysis of 16S rRNA gene amplicons from live, dead, and dormant cells revealed how communities differ between these pools, how they are influenced by soil physicochemical properties, and whether they change over geologic time. We found evidence that cells capable of forming endospores are not necessarily dormant and that members of the class Bacilli were more likely to form endospores in response to long-term stressors associated with permafrost environmental conditions than members of the Clostridia, which were more likely to persist as vegetative cells in our older samples. We also found that removing exogenous &quot;relic&quot; DNA preserved within permafrost did not significantly alter microbial community composition. These results link the live, dead, and dormant microbial communities to physicochemical characteristics and provide insights into the survival of microbial communities in ancient permafrost.IMPORTANCE Permafrost soils store more than half of Earth's soil carbon despite covering ∼15% of the land area (C. Tarnocai et al., Global Biogeochem Cycles 23:GB2023, 2009, https://doi.org/10.1029/2008GB003327). This permafrost carbon is rapidly degraded following a thaw (E. A. G. Schuur et al., Nature 520:171-179, 2015, https://doi.org/10.1038/nature14338). Understanding microbial communities in permafrost will contribute to the knowledge base necessary to understand the rates and forms of permafrost C and N cycling postthaw. Permafrost is also an analog for frozen extraterrestrial environments, and evidence of viable organisms in ancient permafrost is of interest to those searching for potential life on distant worlds. If we can identify strategies microbial communities utilize to survive in permafrost, it may yield insights into how life (if it exists) survives in frozen environments outside of Earth. Our work is significant because it contributes to an understanding of how microbial life adapts and survives in the extreme environmental conditions in permafrost terrains.}, }
@article {pmid30680433, year = {2019}, author = {Goetghebuer, L and Bonal, M and Faust, K and Servais, P and George, IF}, title = {The Dynamic of a River Model Bacterial Community in Two Different Media Reveals a Divergent Succession and an Enhanced Growth of Most Strains Compared to Monocultures.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01322-w}, pmid = {30680433}, issn = {1432-184X}, support = {T.1037.14//Fonds De La Recherche Scientifique - FRS-FNRS (BE)/ ; }, abstract = {The dynamic of a community of 20 bacterial strains isolated from river water was followed in R2 broth and in autoclaved river water medium for 27 days in batch experiments. At an early stage of incubation, a fast-growing specialist strain, Acinetobater sp., dominated the community in both media. Later on, the community composition in both media diverged but was highly reproducible across replicates. In R2, several strains previously reported to degrade multiple simple carbon sources prevailed. In autoclaved river water, the community was more even and became dominated by several strains growing faster or exclusively in that medium. Those strains have been reported in the literature to degrade complex compounds. Their growth rate in the community was 1.5- to 7-fold greater than that observed in monoculture. Furthermore, those strains developed simultaneously in the community. Together, our results suggest the existence of cooperative interactions within the community incubated in autoclaved river water.}, }
@article {pmid30678814, year = {2019}, author = {Lavefve, L and Marasini, D and Carbonero, F}, title = {Microbial Ecology of Fermented Vegetables and Non-Alcoholic Drinks and Current Knowledge on Their Impact on Human Health.}, journal = {Advances in food and nutrition research}, volume = {87}, number = {}, pages = {147-185}, doi = {10.1016/bs.afnr.2018.09.001}, pmid = {30678814}, issn = {1043-4526}, abstract = {Fermented foods are currently experiencing a re-discovery, largely driven by numerous health benefits claims. While fermented dairy, beer, and wine (and other alcoholic fermented beverages) have been the subject of intensive research, other plant-based fermented foods that are in some case widely consumed (kimchi/sauerkraut, pickles, kombucha) have received less scientific attention. In this chapter, the current knowledge on the microbiology and potential health benefits of such plant-based fermented foods are presented. Kimchi is the most studied, characterized by primarily acidic fermentation by lactic acid bacteria. Anti-obesity and anti-hypertension properties have been reported for kimchi and other pickled vegetables. Kombucha is the most popular non-alcoholic fermented drink. Kombucha's microbiology is remarkable as it involves all fermenters described in known fermented foods: lactic acid bacteria, acetic acid bacteria, fungi, and yeasts. While kombucha is often hyped as a &quot;super-food,&quot; only antioxidant and antimicrobial properties toward foodborne pathogens are well established; and it is unknown if these properties incur beneficial impact, even in vitro or in animal models. The mode of action that has been studied and demonstrated the most is the probiotic one. However, it can be expected that fermentation metabolites may be prebiotic, or influence host health directly. To conclude, plant-based fermented foods and drinks are usually safe products; few negative reports can be found, but more research, especially human dietary intervention studies, are warranted to substantiate any health claim.}, }
@article {pmid30678161, year = {2019}, author = {Snelson, M and Coughlan, MT}, title = {Dietary Advanced Glycation End Products: Digestion, Metabolism and Modulation of Gut Microbial Ecology.}, journal = {Nutrients}, volume = {11}, number = {2}, pages = {}, doi = {10.3390/nu11020215}, pmid = {30678161}, issn = {2072-6643}, mesh = {Animals ; *Diet ; Digestion/*drug effects ; Food ; Gastrointestinal Microbiome/*drug effects ; Glycation End Products, Advanced/*metabolism/*pharmacology ; Humans ; }, abstract = {The formation of advanced glycation end products (AGEs) in foods is accelerated with heat treatment, particularly within foods that are cooked at high temperatures for long periods of time using dry heat. The modern processed diet is replete with AGEs, and excessive AGE consumption is thought to be associated with a number of negative health effects. Many dietary AGEs have high molecular weight and are not absorbed in the intestine, and instead pass through to the colon, where they are available for metabolism by the colonic bacteria. Recent studies have been conducted to explore the effects of AGEs on the composition of the gut microbiota as well as the production of beneficial microbial metabolites, in particular, short-chain fatty acids. However, there is conflicting evidence regarding the impact of dietary AGEs on gut microbiota reshaping, which may be due, in part, to the formation of alternate compounds during the thermal treatment of foods. This review summarises the current evidence regarding dietary sources of AGEs, their gastrointestinal absorption and role in gut microbiota reshaping, provides a brief overview of the health implications of dietary AGEs and highlights knowledge gaps and avenues for future study.}, }
@article {pmid30677885, year = {2019}, author = {Young, JM and Skvortsov, T and Kelleher, BP and Mahaney, WC and Somelar, P and Allen, CCR}, title = {Effect of soil horizon stratigraphy on the microbial ecology of alpine paleosols.}, journal = {The Science of the total environment}, volume = {657}, number = {}, pages = {1183-1193}, doi = {10.1016/j.scitotenv.2018.11.442}, pmid = {30677885}, issn = {1879-1026}, mesh = {Bacteria/classification/genetics ; Biodiversity ; France ; High-Throughput Nucleotide Sequencing ; Metals/analysis ; Microbial Consortia/genetics ; Principal Component Analysis ; Soil/*chemistry ; *Soil Microbiology ; }, abstract = {There is remarkable potential for research at the interface between the earth sciences and environmental microbiology that may lead to advances in our understanding of the role of bacterial communities in the surface or subsurface environment of our planet. One mainstay of sedimentary classification is the concept of differential soil and/or paleosol horizons being the result of primarily physical and chemical weathering, with relatively little understanding of how microbial communities between these stratified horizons differ, if at all. In this study we evaluate the differences in microbial community taxonomy and biogeochemical functional potential between stratified soil horizons in an alpine paleosol environment using next-generation sequencing (NGS) shotgun sequencing. Paleosols represent a unique environment to study the effect of differences soil horizon environments on the microbial community due to their relative isolation, and the fact that three distinct stratified soil horizons can be identified within the top 30 cm of the soil. This enables us to assess variation in microbial community composition that will be relatively distinct from variation due to distance alone. We test the hypothesis that variation in soil community composition is linked to variation in the physical and chemical parameters that define stratigraphy. Multivariate statistical analysis of sequencing reads from soil horizons across five sampling sites revealed that 1223 microbial genera vary significantly and consistently in abundance across stratified soil horizons at class level. Specifically Ktedonobacter, Bacilli and Betaproteobacteria responded most strongly to soil depth. Alpha diversity showed a positive correlation with soil depth. Beta diversity, however, did not differ significantly between horizons. Genes involved in carbohydrate and nitrogen metabolism were found to be more abundant in Ah horizon samples. Closer inspection of carbohydrate metabolism genes revealed that genes involved in CO2 fixation, fermentation and saccharide metabolism decreased in abundance with depth while one‑carbon metabolism increased down profile.}, }
@article {pmid30674322, year = {2019}, author = {Adela, R and Reddy, PNC and Ghosh, TS and Aggarwal, S and Yadav, AK and Das, B and Banerjee, SK}, title = {Serum protein signature of coronary artery disease in type 2 diabetes mellitus.}, journal = {Journal of translational medicine}, volume = {17}, number = {1}, pages = {17}, doi = {10.1186/s12967-018-1755-5}, pmid = {30674322}, issn = {1479-5876}, abstract = {BACKGROUND: Coronary artery disease (CAD) is the leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). The purpose of the present study was to discriminate the Indian CAD patients with or without T2DM by using multiple pathophysiological biomarkers.<br><br>METHODS: Using sensitive multiplex protein assays, we assessed 46 protein markers including cytokines/chemokines, metabolic hormones, adipokines and apolipoproteins for evaluating different pathophysiological conditions of control, T2DM, CAD and T2DM with CAD patients (T2DM_CAD). Network analysis was performed to create protein-protein interaction networks by using significantly (p < 0.05) altered protein markers in each disease using STRING 10.5 database. We used two supervised analysis methods i.e., between class analysis (BCA) and principal component analysis (PCA) to reveals distinct biomarkers profiles. Further, random forest classification (RF) was used to classify the diseases by the panel of markers.<br><br>RESULTS: Our two supervised analysis methods BCA and PCA revealed a distinct biomarker profiles and high degree of variability in the marker profiles for T2DM_CAD and CAD. Thereafter, the present study identified multiple potential biomarkers to differentiate T2DM, CAD, and T2DM_CAD patients based on their relative abundance in serum. RF classified T2DM based on the abundance patterns of nine markers i.e., IL-1β, GM-CSF, glucagon, PAI-I, rantes, IP-10, resistin, GIP and Apo-B; CAD by 14 markers i.e., resistin, PDGF-BB, PAI-1, lipocalin-2, leptin, IL-13, eotaxin, GM-CSF, Apo-E, ghrelin, adipsin, GIP, Apo-CII and IP-10; and T2DM _CAD by 12 markers i.e., insulin, resistin, PAI-1, adiponectin, lipocalin-2, GM-CSF, adipsin, leptin, Apo-AII, rantes, IL-6 and ghrelin with respect to the control subjects. Using network analysis, we have identified several cellular network proteins like PTPN1, AKT1, INSR, LEPR, IRS1, IRS2, IL1R2, IL6R, PCSK9 and MYD88, which are responsible for regulating inflammation, insulin resistance, and atherosclerosis.<br><br>CONCLUSION: We have identified three distinct sets of serum markers for diabetes, CAD and diabetes associated with CAD in Indian patients using nonparametric-based machine learning approach. These multiple marker classifiers may be useful for monitoring progression from a healthy person to T2DM and T2DM to T2DM_CAD. However, these findings need to be further confirmed in the future studies with large number of samples.}, }
@article {pmid30668615, year = {2019}, author = {Snelson, M and Kellow, NJ and Coughlan, MT}, title = {Modulation of the Gut Microbiota by Resistant Starch as a Treatment of Chronic Kidney Diseases: Evidence of Efficacy and Mechanistic Insights.}, journal = {Advances in nutrition (Bethesda, Md.)}, volume = {10}, number = {2}, pages = {303-320}, doi = {10.1093/advances/nmy068}, pmid = {30668615}, issn = {2156-5376}, abstract = {Chronic kidney disease (CKD) has been associated with changes in gut microbial ecology, or &quot;dysbiosis,&quot; which may contribute to disease progression. Recent studies have focused on dietary approaches to favorably alter the composition of the gut microbial communities as a treatment method in CKD. Resistant starch (RS), a prebiotic that promotes proliferation of gut bacteria such as Bifidobacteria and Lactobacilli, increases the production of metabolites including short-chain fatty acids, which confer a number of health-promoting benefits. However, there is a lack of mechanistic insight into how these metabolites can positively influence renal health. Emerging evidence shows that microbiota-derived metabolites can regulate the incretin axis and mitigate inflammation via expansion of regulatory T cells. Studies from animal models and patients with CKD show that RS supplementation attenuates the concentrations of uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate. Here, we present the current state of knowledge linking the microbiome to CKD, we explore the efficacy of RS in animal models of CKD and in humans with the condition, and we discuss how RS supplementation could be a promising dietary approach for slowing CKD progression.}, }
@article {pmid30666369, year = {2019}, author = {Zhou, D and Feng, H and Schuelke, T and De Santiago, A and Zhang, Q and Zhang, J and Luo, C and Wei, L}, title = {Rhizosphere Microbiomes from Root Knot Nematode Non-infested Plants Suppress Nematode Infection.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01319-5}, pmid = {30666369}, issn = {1432-184X}, support = {31601685//National Natural Science Foundation of China/ ; CARS-24-C-01//Agriculture Research System of China/ ; 201403032//Special Fund for Agro-scientific Research in the Public Interest/ ; 4921701//Key Research and Development Program of Jiangsu Province/ ; }, abstract = {Root knot nematodes (RKN, Meloidogyne spp.) are serious pathogens of numerous crops worldwide. Understanding the roles plant rhizosphere soil microbiome play during RKN infection is very important. The current study aims at investigating the impacts of soil microbiome on the activity of RKN. In this study, the 16S rRNA genes of the bacterial communities from nematode-infested and non-infested rhizosphere soils from four different plants were sequenced on the Illumina Hi-Seq platform. The soil microbiome effects on RKN infection were tested in a greenhouse assay. The non-infested soils had more microbial diversity than the infested soils from all plant rhizospheres, and both soil types had exclusive microbial communities. The inoculation of the microbiomes from eggplant and cucumber non-infested soils to tomato plants significantly alleviated the RKN infection, while the microbiome from infested soil showed increased the RKN infection. Furthermore, bacteria Pseudomonas sp. and Bacillus sp. were screened out from non-infested eggplant soil and exhibited biocontrol activity to RKN on tomato. Our findings suggest that microbes may regulate RKN infection in plants and are involved in biocontrol of RKN.}, }
@article {pmid30666368, year = {2019}, author = {Clifford, EL and Varela, MM and De Corte, D and Bode, A and Ortiz, V and Herndl, GJ and Sintes, E}, title = {Taurine Is a Major Carbon and Energy Source for Marine Prokaryotes in the North Atlantic Ocean off the Iberian Peninsula.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01320-y}, pmid = {30666368}, issn = {1432-184X}, support = {P27696-B22//Austrian Science Fund/ ; I486-B09//Austrian Science Fund/ ; Z194-B17//Austrian Science Fund/ ; 268595//FP7 Ideas: European Research Council (FP7/2007-2013)/ ; 10MMA604024PR, 2010-2012//Xunta de Galicia/ ; CTM2011-24008//Ministerio de Econom?a y Competitividad/ ; }, abstract = {Taurine, an amino acid-like compound, acts as an osmostress protectant in many marine metazoans and algae and is released via various processes into the oceanic dissolved organic matter pool. Taurine transporters are widespread among members of the marine prokaryotic community, tentatively indicating that taurine might be an important substrate for prokaryotes in the ocean. In this study, we determined prokaryotic taurine assimilation and respiration throughout the water column along two transects in the North Atlantic off the Iberian Peninsula. Taurine assimilation efficiency decreased from the epipelagic waters from 55 ± 14% to 27 ± 20% in the bathypelagic layers (means of both transects). Members of the ubiquitous alphaproteobacterial SAR11 clade accounted for a large fraction of cells taking up taurine, especially in surface waters. Archaea (Thaumarchaeota + Euryarchaeota) were also able to take up taurine in the upper water column, but to a lower extent than Bacteria. The contribution of taurine assimilation to the heterotrophic prokaryotic carbon biomass production ranged from 21% in the epipelagic layer to 16% in the bathypelagic layer. Hence, we conclude that dissolved free taurine is a significant carbon and energy source for prokaryotes throughout the oceanic water column being utilized with similar efficiencies as dissolved free amino acids.}, }
@article {pmid30666243, year = {2018}, author = {Zhang, F and Xu, X and Huo, Y and Xiao, Y}, title = {Trichoderma-Inoculation and Mowing Synergistically Altered Soil Available Nutrients, Rhizosphere Chemical Compounds and Soil Microbial Community, Potentially Driving Alfalfa Growth.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3241}, doi = {10.3389/fmicb.2018.03241}, pmid = {30666243}, issn = {1664-302X}, abstract = {Trichoderma spp. are proposed as major plant growth-promoting fungi (PGPF) to increase plants growth and productivity. Mowing can stimulate aboveground regrowth to improve plant biomass and nutritional quality. However, the synergistic effects of Trichoderma and mowing on plants growth, particularly the underlying microbial mechanisms mediated by rhizosphere soil chemical compounds, have rarely been reported. In the present study, we employed Trichoderma harzianum T-63 and conducted a pot experiment to investigate the synergistic effect of Trichoderma-inoculation and mowing on alfalfa growth, and the potential soil microbial ecological mechanisms were also explored. Alfalfa treated with Trichoderma-inoculation and/or mowing (T, M, and TM) had significant (P < 0.05) increases in plant shoot and root dry weights and soil available nutrients (N, P, and K), compared with those of the control (CK). Non-metric multidimensional scaling (NMDS) demonstrated that the rhizosphere chemical compounds and soil bacterial and fungal communities were, respectively, separated according to different treatments. There was a clear significant (P < 0.05) positive correlation between alfalfa biomass and the relative abundance of Trichoderma (R2 = 0.3451, P = 0.045). However, Pseudomonas, Flavobacterium, Arthrobacter, Bacillus, Agrobacterium, and Actinoplanes were not significantly correlated with alfalfa biomass. According to structure equation modeling (SEM), Trichoderma abundance and available P served as primary contributors to alfalfa growth promotion. Additionally, Trichoderma-inoculation and mowing altered rhizosphere soil chemical compounds to drive the soil microbial community, indirectly influencing alfalfa growth. Our research provides a basis for promoting alfalfa growth from a soil microbial ecology perspective and may provide a scientific foundation for guiding the farming of alfalfa.}, }
@article {pmid30666239, year = {2018}, author = {Dinakaran, V and Mandape, SN and Shuba, K and Pratap, S and Sakhare, SS and Tabatabai, MA and Smoot, DT and Farmer-Dixon, CM and Kesavalu, LN and Adunyah, SE and Southerland, JH and Gangula, PR}, title = {Identification of Specific Oral and Gut Pathogens in Full Thickness Colon of Colitis Patients: Implications for Colon Motility.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3220}, doi = {10.3389/fmicb.2018.03220}, pmid = {30666239}, issn = {1664-302X}, support = {U54 CA163069/CA/NCI NIH HHS/United States ; G12 MD007586/MD/NIMHD NIH HHS/United States ; U54 MD007586/MD/NIMHD NIH HHS/United States ; U54 MD007593/MD/NIMHD NIH HHS/United States ; SC1 GM121282/GM/NIGMS NIH HHS/United States ; }, abstract = {Impaired colon motility is one of the leading problems associated with inflammatory bowel disease (IBD). An expanding body of evidence supports the role of microbiome in normal gut function and in progression of IBD. The objective of this work is to determine whether diseased full thickness colon specimens, including the neuromuscular region (critical for colon motility function), contain specific oral and gut pathogens. In addition, we compared the differences in colon microbiome between Caucasians (CA) and African Americans (AA). Thirty-nine human full thickness colon (diseased colon and adjacent healthy colon) specimens were collected from Crohn's Colitis (CC) or Ulcerative Colitis (UC) patients while they underwent elective colon surgeries. We isolated and analyzed bacterial ribosomal RNA (rRNA) from colon specimens by amplicon sequencing of the 16S rRNA gene region. The microbiome proportions were quantified into Operational Taxonomic Units (OTUs) by analysis with Quantitative Insights Into Microbial ecology (QIIME) platform. Two hundred twenty-eight different bacterial species were identified by QIIME analysis. However, we could only decipher the species name of fifty-three bacteria. Our results show that proportion of non-detrimental bacteria in CC or UC colon samples were altered compared to adjacent healthy colon specimens. We further show, for the first time in full thickness colon specimens, that microbiome of CC and UC diseased specimens is dominated by putative oral pathogens belonging to the Phyla Firmicutes (Streptococcus, Staphylococcus, Peptostreptococcus), and Fusobacteria (Fusobacterium). In addition, we have identified patterns of differences in microbiome levels between CA and AA specimens with potential implications for health disparities research. Overall, our results suggest a significant association between oral and gut microbes in the modulation of colon motility in colitis patients.}, }
@article {pmid30661111, year = {2019}, author = {Plotnikov, AO and Balkin, AS and Gogoleva, NE and Lanzoni, O and Khlopko, YA and Cherkasov, SV and Potekhin, AA}, title = {High-Throughput Sequencing of the 16S rRNA Gene as a Survey to Analyze the Microbiomes of Free-Living Ciliates Paramecium.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01321-x}, pmid = {30661111}, issn = {1432-184X}, support = {16-14-10157//Russian Science Foundation/ ; 14-04-01796//Russian Foundation for Basic Research/ ; }, abstract = {Ciliates are the largest group of ubiquitous aquatic bacterivorous protists, and many species are easily cultivated. However, only few studies reported prokaryotic communities naturally associated with ciliate cells. Herein, we analyzed the microbiome composition of several strains of Paramecium (Ciliophora) originating from different locations and belonging to two morpho-species by high-throughput sequencing (HTS) of the 16S rRNA gene. Possible reasons of HTS results bias were addressed comparing DNA libraries obtained using different primers and different number of ciliate cells. Microbiomes associated with ciliates and their environments were always significantly different by prokaryotic taxonomic composition and bacterial richness. There were also pronounced differences between Paramecium strains. Interestingly, potentially pathogenic bacteria were revealed in Paramecium microbiomes.}, }
@article {pmid30658982, year = {2019}, author = {Jiao, S and Chen, W and Wei, G}, title = {Resilience and Assemblage of Soil Microbiome in Response to Chemical Contamination Combined with Plant Growth.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {6}, pages = {}, doi = {10.1128/AEM.02523-18}, pmid = {30658982}, issn = {1098-5336}, abstract = {A lack of knowledge of the microbial responses to environmental change at the species and functional levels hinders our ability to understand the intrinsic mechanisms underlying the maintenance of microbial ecosystems. Here, we present results from temporal microcosms that introduced inorganic and organic contaminants into agro-soils for 90 days, with three common legume plants. Temporal dynamics and assemblage of soil microbial communities and functions in response to contamination under the influence of growth of different plants were explored via sequencing of the 16S rRNA amplicon and by shotgun metagenomics. Soil microbial alpha diversity and structure at the taxonomic and functional levels exhibited resilience patterns. Functional profiles showed greater resilience than did taxonomic ones. Different legume plants imposed stronger selection on taxonomic profiles than on functional ones. Network and random forest analyses revealed that the functional potential of soil microbial communities was fostered by various taxonomic groups. Betaproteobacteria were important predictors of key functional traits such as amino acid metabolism, nucleic acid metabolism, and hydrocarbon degradation. Our study reveals the strong resilience of the soil microbiome to chemical contamination and sensitive responses of taxonomic rather than functional profiles to selection processes induced by different legume plants. This is pivotal to develop approaches and policies for the protection of soil microbial diversity and functions in agro-ecosystems with different response strategies from global environmental drivers, such as soil contamination and plant invasion.IMPORTANCE Exploring the microbial responses to environmental disturbances is a central issue in microbial ecology. Understanding the dynamic responses of soil microbial communities to chemical contamination and the microbe-soil-plant interactions is essential for forecasting the long-term changes in soil ecosystems. Nevertheless, few studies have applied multi-omics approaches to assess the microbial responses to soil contamination and the microbe-soil-plant interactions at the taxonomic and functional levels simultaneously. Our study reveals clear succession and resilience patterns of soil microbial diversity and structure in response to chemical contamination. Different legume plants exerted stronger selection processes on taxonomic than on functional profiles in contaminated soils, which could benefit plant growth and fitness as well as foster the potential abilities of hydrocarbon degradation and metal tolerance. These results provide new insight into the resilience and assemblage of soil microbiome in response to environmental disturbances in agro-ecosystems at the species and functional levels.}, }
@article {pmid30655101, year = {2018}, author = {Wolters, M and Ahrens, J and Romaní-Pérez, M and Watkins, C and Sanz, Y and Benítez-Páez, A and Stanton, C and Günther, K}, title = {Dietary fat, the gut microbiota, and metabolic health - A systematic review conducted within the MyNewGut project.}, journal = {Clinical nutrition (Edinburgh, Scotland)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.clnu.2018.12.024}, pmid = {30655101}, issn = {1532-1983}, abstract = {BACKGROUND AND AIMS: Studies indicate that dietary fat quantity and quality influence the gut microbiota composition which may as a consequence impact metabolic health. This systematic review aims to summarize the results of available studies in humans on dietary fat intake (quantity and quality), the intestinal microbiota composition and related cardiometabolic health outcomes.<br><br>METHODS: We performed a systematic review (CRD42018088685) following PRISMA guidelines and searched for literature in Medline, EMBASE, and Cochrane databases.<br><br>RESULTS: From 796 records, 765 records were excluded based on title or abstract. After screening of 31 full-text articles six randomized controlled trials (RCT) and nine cross-sectional observational studies were included. Our results of interventional trials do not suggest strong effects of different amounts and types of dietary fat on the intestinal microbiota composition or on metabolic health outcomes while observational studies indicate associations with the microbiota and health outcomes. High intake of fat and saturated fatty acids (SFA) may negatively affect microbiota richness and diversity and diets high in monounsaturated fatty acids (MUFA) may decrease total bacterial numbers whereas dietary polyunsaturated fatty acids (PUFA) had no effect on richness and diversity.<br><br>CONCLUSIONS: High fat and high SFA diets can exert unfavorable effects on the gut microbiota and are associated with an unhealthy metabolic state. Also high MUFA diets may negatively affect gut microbiota whereas PUFA do not seem to negatively affect the gut microbiota or metabolic health outcomes. However, data are not consistent and most RCT and observational studies showed risks of bias.}, }
@article {pmid30654982, year = {2019}, author = {Mandalakis, M and Gavriilidou, A and Polymenakou, PN and Christakis, CA and Nomikou, P and Medvecký, M and Kilias, SP and Kentouri, M and Kotoulas, G and Magoulas, A}, title = {Microbial strains isolated from CO2-venting Kolumbo submarine volcano show enhanced co-tolerance to acidity and antibiotics.}, journal = {Marine environmental research}, volume = {144}, number = {}, pages = {102-110}, doi = {10.1016/j.marenvres.2019.01.002}, pmid = {30654982}, issn = {1879-0291}, abstract = {As ocean acidification intensifies, there is growing global concern about the impacts that future pH levels are likely to have on marine life and ecosystems. By analogy, a steep decrease of seawater pH with depth is encountered inside the Kolumbo submarine volcano (northeast Santorini) as a result of natural CO2 venting, making this system ideal for ocean acidification research. Here, we investigated whether the increase of acidity towards deeper layers of Kolumbo crater had any effect on relevant phenotypic traits of bacterial isolates. A total of 31 Pseudomonas strains were isolated from both surface- (SSL) and deep-seawater layers (DSL), with the latter presenting a significantly higher acid tolerance. In particular, the DSL strains were able to cope with H+ levels that were 18 times higher. Similarly, the DSL isolates exhibited a significantly higher tolerance than SSL strains against six commonly used antibiotics and As(III). More importantly, a significant positive correlation was revealed between antibiotics and acid tolerance across the entire set of SSL and DSL isolates. Our findings imply that Pseudomonas species with higher resilience to antibiotics could be favored by the prospect of acidifying oceans. Further studies are required to determine if this feature is universal across marine bacteria and to assess potential ecological impacts.}, }
@article {pmid30653351, year = {2019}, author = {Alvarez-Ordóñez, A and Coughlan, LM and Briandet, R and Cotter, PD}, title = {Biofilms in Food Processing Environments: Challenges and Opportunities.}, journal = {Annual review of food science and technology}, volume = {10}, number = {}, pages = {173-195}, doi = {10.1146/annurev-food-032818-121805}, pmid = {30653351}, issn = {1941-1421}, abstract = {This review examines the impact of microbial communities colonizing food processing environments in the form of biofilms on food safety and food quality. The focus is both on biofilms formed by pathogenic and spoilage microorganisms and on those formed by harmless or beneficial microbes, which are of particular relevance in the processing of fermented foods. Information is presented on intraspecies variability in biofilm formation, interspecies relationships of cooperativism or competition within biofilms, the factors influencing biofilm ecology and architecture, and how these factors may influence removal. The effect on the biofilm formation ability of particular food components and different environmental conditions that commonly prevail during food processing is discussed. Available tools for the in situ monitoring and characterization of wild microbial biofilms in food processing facilities are explored. Finally, research on novel agents or strategies for the control of biofilm formation or removal is summarized.}, }
@article {pmid30647456, year = {2019}, author = {Junghare, M and Spiteller, D and Schink, B}, title = {Anaerobic degradation of xenobiotic isophthalate by the fermenting bacterium Syntrophorhabdus aromaticivorans.}, journal = {The ISME journal}, volume = {13}, number = {5}, pages = {1252-1268}, doi = {10.1038/s41396-019-0348-5}, pmid = {30647456}, issn = {1751-7370}, abstract = {Syntrophorhabdus aromaticivorans is a syntrophically fermenting bacterium that can degrade isophthalate (3-carboxybenzoate). It is a xenobiotic compound which has accumulated in the environment for more than 50 years due to its global industrial usage and can cause negative effects on the environment. Isophthalate degradation by the strictly anaerobic S. aromaticivorans was investigated to advance our understanding of the degradation of xenobiotics introduced into nature, and to identify enzymes that might have ecological significance for bioremediation. Differential proteome analysis of isophthalate- vs benzoate-grown cells revealed over 400 differentially expressed proteins of which only four were unique to isophthalate-grown cells. The isophthalate-induced proteins include a phenylacetate:CoA ligase, a UbiD-like decarboxylase, a UbiX-like flavin prenyltransferase, and a hypothetical protein. These proteins are encoded by genes forming a single gene cluster that putatively codes for anaerobic conversion of isophthalate to benzoyl-CoA. Subsequently, benzoyl-CoA is metabolized by the enzymes of the anaerobic benzoate degradation pathway that were identified in the proteomic analysis. In vitro enzyme assays with cell-free extracts of isophthalate-grown cells indicated that isophthalate is activated to isophthalyl-CoA by an ATP-dependent isophthalate:CoA ligase (IPCL), and subsequently decarboxylated to benzoyl-CoA by a UbiD family isophthalyl-CoA decarboxylase (IPCD) that requires a prenylated flavin mononucleotide (prFMN) cofactor supplied by UbiX to effect decarboxylation. Phylogenetic analysis revealed that IPCD is a novel member of the functionally diverse UbiD family (de)carboxylases. Homologs of the IPCD encoding genes are found in several other bacteria, such as aromatic compound-degrading denitrifiers, marine sulfate-reducers, and methanogenic communities in a terephthalate-degrading reactor. These results suggest that metabolic strategies adapted for degradation of isophthalate and other phthalate are conserved between microorganisms that are involved in the anaerobic degradation of environmentally relevant aromatic compounds.}, }
@article {pmid30640580, year = {2019}, author = {Cornut, J and De Respinis, S and Tonolla, M and Petrini, O and Bärlocher, F and Chauvet, E and Bruder, A}, title = {Rapid characterization of aquatic hyphomycetes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.}, journal = {Mycologia}, volume = {111}, number = {1}, pages = {177-189}, doi = {10.1080/00275514.2018.1528129}, pmid = {30640580}, issn = {1557-2536}, mesh = {Cluster Analysis ; France ; Fungal Proteins/*analysis ; Mitosporic Fungi/chemistry/*classification ; *Phylogeny ; Proteomics ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; *Water Microbiology ; }, abstract = {Protein fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI--TOF MS) is a rapid, reliable, and economical method to characterize isolates of terrestrial fungi and other microorganisms. The objective of our study was to evaluate the suitability of MALDI-TOF MS for the identification of aquatic hyphomycetes, a polyphyletic group of fungi that play crucial roles in stream ecosystems. To this end, we used 34 isolates of 21 aquatic hyphomycete species whose identity was confirmed by spore morphology and internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) nuc rDNA sequencing. We tested the efficiency of three protein extraction methods, including chemical and mechanical treatments using 13 different protocols, with the objective of producing high-quality MALDI-TOF mass spectra. In addition to extraction protocols, mycelium age was identified as a key parameter affecting protein extraction efficiency. The dendrogram based on mass-spectrum similarity indicated good and relevant taxonomic discrimination; the tree structure was comparable to that of the phylogram based on ITS sequences. Consequently, MALDI-TOF MS could reliably identify the isolates studied and provided greater taxonomic accuracy than classical morphological methods. MALDI-TOF MS seems suited for rapid characterization and identification of aquatic hyphomycete species.}, }
@article {pmid30636276, year = {2019}, author = {Zak, DR and Pellitier, PT and Argiroff, W and Castillo, B and James, TY and Nave, LE and Averill, C and Beidler, KV and Bhatnagar, J and Blesh, J and Classen, AT and Craig, M and Fernandez, CW and Gundersen, P and Johansen, R and Koide, RT and Lilleskov, EA and Lindahl, BD and Nadelhoffer, KJ and Phillips, RP and Tunlid, A}, title = {Exploring the role of ectomycorrhizal fungi in soil carbon dynamics.}, journal = {The New phytologist}, volume = {223}, number = {1}, pages = {33-39}, doi = {10.1111/nph.15679}, pmid = {30636276}, issn = {1469-8137}, abstract = {The extent to which ectomycorrhizal (ECM) fungi enable plants to access organic nitrogen (N) bound in soil organic matter (SOM) and transfer this growth-limiting nutrient to their plant host, has important implications for our understanding of plant-fungal interactions, and the cycling and storage of carbon (C) and N in terrestrial ecosystems. Empirical evidence currently supports a range of perspectives, suggesting that ECM vary in their ability to provide their host with N bound in SOM, and that this capacity can both positively and negatively influence soil C storage. To help resolve the multiplicity of observations, we gathered a group of researchers to explore the role of ECM fungi in soil C dynamics, and propose new directions that hold promise to resolve competing hypotheses and contrasting observations. In this Viewpoint, we summarize these deliberations and identify areas of inquiry that hold promise for increasing our understanding of these fundamental and widespread plant symbionts and their role in ecosystem-level biogeochemistry.}, }
@article {pmid30635381, year = {2019}, author = {Yao, Z and Du, S and Liang, C and Zhao, Y and Dini-Andreote, F and Wang, K and Zhang, D}, title = {Bacterial Community Assembly in a Typical Estuarine Marsh with Multiple Environmental Gradients.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {6}, pages = {}, doi = {10.1128/AEM.02602-18}, pmid = {30635381}, issn = {1098-5336}, abstract = {Bacterial communities play essential roles in estuarine marsh ecosystems, but the interplay of ecological processes underlying their community assembly is poorly understood. Here, we studied the sediment bacterial communities along a linear gradient extending from the water-land junction toward a high marsh, using 16S rRNA gene amplicon sequencing. Bacterial community compositions differed significantly between sediment transects. Physicochemical properties, particularly sediment nutrient levels (i.e., total nitrogen [TN] and available phosphorus [AP]), as well as sediment physical structure and pH (P < 0.05), were strongly associated with the overall community variations. In addition, the topological properties of bacterial cooccurrence networks varied with distance to the water-land junction. Both node- and network-level topological features revealed that the bacterial network of sediments farthest from the junction was less intense in complexity and interactions than other sediments. Phylogenetic null modeling analysis showed a progressive transition from stochastic to deterministic community assembly for the water-land junction sites toward the emerging terrestrial system. Taken together, data from this study provide a detailed outline of the distribution pattern of the sediment bacterial community across an estuarine marsh and inform the mechanisms and processes mediating bacterial community assembly in marsh soils.IMPORTANCE Salt marshes represent highly dynamic ecosystems where the atmosphere, continents, and the ocean interact. The bacterial distribution in this ecosystem is of great ecological concern, as it provides essential functions acting on ecosystem services. However, ecological processes mediating bacterial assembly are poorly understood for salt marshes, especially the ones located in estuaries. In this study, the distribution and assembly of bacterial communities in an estuarine marsh located in south Hangzhou Bay were investigated. The results revealed an intricate interplay between stochastic and deterministic processes mediating the assembly of bacterial communities in the studied gradient system. Collectively, our findings illustrate the main drivers of community assembly, taking into consideration changes in sediment abiotic variables and potential biotic interactions. Thus, we offer new insights into estuarine bacterial communities and illustrate the interplay of ecological processes shaping the assembly of bacterial communities in estuarine marsh ecosystems.}, }
@article {pmid30633563, year = {2019}, author = {Tomás-Barberán, FA and Espín, JC}, title = {Effect of Food Structure and Processing on (Poly)phenol-Gut Microbiota Interactions and the Effects on Human Health.}, journal = {Annual review of food science and technology}, volume = {10}, number = {}, pages = {221-238}, doi = {10.1146/annurev-food-032818-121615}, pmid = {30633563}, issn = {1941-1421}, abstract = {The two-way interaction of food (poly)phenols with the human gut microbiota has been studied throughout the past ten years. Research has shown that this interaction can be relevant to explain the health effects of these phytochemicals. The effect of the food matrix and food processing on this interaction has only been partially studied. In this article, the studies within this field have been critically reviewed, with a special focus on the following groups of phenolic metabolites: citrus flavanones, pomegranate ellagitannins, and cocoa proanthocyanidins. The available research shows that both the food matrix and food processing can be relevant factors for gut microbiota reshaping to reach a healthier microbial ecology and for the conversion of polyphenols to bioactive and bioavailable metabolites. There are, however, some research gaps that indicate a more comprehensive research approach is needed to reach valid conclusions regarding the gut microbiota-mediated effects of polyphenols on human health.}, }
@article {pmid30629579, year = {2019}, author = {Miranda-CasoLuengo, R and Lu, J and Williams, EJ and Miranda-CasoLuengo, AA and Carrington, SD and Evans, ACO and Meijer, WG}, title = {Delayed differentiation of vaginal and uterine microbiomes in dairy cows developing postpartum endometritis.}, journal = {PloS one}, volume = {14}, number = {1}, pages = {e0200974}, doi = {10.1371/journal.pone.0200974}, pmid = {30629579}, issn = {1932-6203}, abstract = {Bacterial overgrowth in the uterus is a normal event after parturition. In contrast to the healthy cow, animals unable to control the infection within 21 days after calving develop postpartum endometritis. Studies on the Microbial Ecology of the bovine reproductive tract have focused on either vaginal or uterine microbiomes. This is the first study that compares both microbiomes in the same animals. Terminal Restriction Fragment Length Polymorphism of the 16S rRNA gene showed that despite large differences associated to individuals, a shared community exist in vagina and uterus during the postpartum period. The largest changes associated with development of endometritis were observed at 7 days postpartum, a time when vaginal and uterine microbiomes were most similar. 16S rRNA pyrosequencing of the vaginal microbiome at 7 days postpartum showed at least three different microbiome types that were associated with later development of postpartum endometritis. All three microbiome types featured reduced bacterial diversity. Taken together, the above findings support a scenario where disruption of the compartmentalization of the reproductive tract during parturition results in the dispersal and mixing of the vaginal and uterine microbiomes, which subsequently are subject to differentiation. This differentiation was observed early postpartum in the healthy cow. In contrast, loss of bacterial diversity and dominance of the microbiome by few bacterial taxa were related to a delayed succession at 7DPP in cows that at 21 DPP or later were diagnosed with endometritis.}, }
@article {pmid30627762, year = {2019}, author = {Treichel, NS and Prevoršek, Z and Mrak, V and Kostrić, M and Vestergaard, G and Foesel, B and Pfeiffer, S and Stres, B and Schöler, A and Schloter, M}, title = {Effect of the Nursing Mother on the Gut Microbiome of the Offspring During Early Mouse Development.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-019-01317-7}, pmid = {30627762}, issn = {1432-184X}, abstract = {The development of the gut microbiome is influenced by several factors. It is acquired during and after birth and involves both maternal and environmental factors as well as the genetic disposition of the offspring. However, it is unclear if the microbiome development is directly triggered by the mode of delivery and very early contact with the mother or mostly at later stages of initial development mainly by breast milk provided by the mother. To investigate to what extent the gut microbiome composition of the offspring is determined by the nursing mother, providing breast milk, compared to the birth mother during early development, a cross-fostering experiment involving two genetically different mouse lines was developed, being prone to be obese or lean, respectively. The microbiome of the colon was analyzed by high-throughput 16S rRNA gene sequencing, when the mice were 3 weeks old. The nursing mother affected both α- and β-diversity of the offspring's gut microbiome and shaped its composition. Especially bacterial families directly transferred by breast milk, like Streptococcaceae, or families which are strongly influenced by the quality of the breast milk like Rikenellaceae, showed a strong response. The core microbiome transferred from the obese nursing mother showed a higher robustness in comparison to the microbiome transferred from the lean nursing mother. Overall, the nursing mother impacts the gut microbial composition of the offspring during early development and might play an important role for health and disease of the animals at later stages of life.}, }
@article {pmid30627761, year = {2019}, author = {Fokin, SI and Serra, V and Ferrantini, F and Modeo, L and Petroni, G}, title = {&quot;Candidatus Hafkinia simulans&quot; gen. nov., sp. nov., a Novel Holospora-Like Bacterium from the Macronucleus of the Rare Brackish Water Ciliate Frontonia salmastra (Oligohymenophorea, Ciliophora): Multidisciplinary Characterization of the New Endosymbiont and Its Host.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1092-1106}, doi = {10.1007/s00248-018-1311-0}, pmid = {30627761}, issn = {1432-184X}, support = {PRA_2018_63//Università di Pisa/ ; }, mesh = {Holosporaceae/classification/genetics/*physiology/ultrastructure ; Italy ; Macronucleus/microbiology ; Microscopy, Electron, Transmission ; Peniculina/*microbiology/physiology ; Phylogeny ; RNA, Bacterial/analysis ; RNA, Ribosomal, 16S/analysis ; RNA, Ribosomal, 18S/analysis ; Sequence Analysis, DNA ; *Symbiosis ; }, abstract = {We characterized a novel Holospora-like bacterium (HLB) (Alphaproteobacteria, Holosporales) living in the macronucleus of the brackish water ciliate Frontonia salmastra. This bacterium was morphologically and ultrastructurally investigated, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and performed in situ hybridization experiments with a specifically-designed probe. A new taxon, &quot;Candidatus Hafkinia simulans&quot;, was established for this HLB. The phylogeny of the family Holosporaceae based on 16S rRNA gene sequences was inferred, adding to the already available data both the sequence of the novel bacterium and those of other Holospora and HLB species recently characterized. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and placed the new endosymbiont as the sister genus of Holospora. Additionally, the host ciliate F. salmastra, recorded in Europe for the first time, was concurrently described through a multidisciplinary study. Frontonia salmastra's phylogenetic position in the subclass Peniculia and the genus Frontonia was assessed according to 18S rRNA gene sequencing. Comments on the biodiversity of this genus were added according to past and recent literature.}, }
@article {pmid30625192, year = {2019}, author = {Ramírez-Fernández, L and Trefault, N and Carú, M and Orlando, J}, title = {Seabird and pinniped shape soil bacterial communities of their settlements in Cape Shirreff, Antarctica.}, journal = {PloS one}, volume = {14}, number = {1}, pages = {e0209887}, doi = {10.1371/journal.pone.0209887}, pmid = {30625192}, issn = {1932-6203}, abstract = {Seabirds and pinnipeds play an important role in biogeochemical cycling by transferring nutrients from aquatic to terrestrial environments. Indeed, soils rich in animal depositions have generally high organic carbon, nitrogen and phosphorus contents. Several studies have assessed bacterial diversity in Antarctic soils influenced by marine animals; however most have been conducted in areas with significant human impact. Thus, we chose Cape Shirreff, Livingston Island, an Antarctic Specially Protected Area designated mainly to protect the diversity of marine vertebrate fauna, and selected sampling sites with different types of animals coexisting in a relatively small space, and where human presence and impact are negligible. Using 16S rRNA gene analyses through massive sequencing, we assessed the influence of animal concentrations, via their modification of edaphic characteristics, on soil bacterial diversity and composition. The nutrient composition of soils impacted by Antarctic fur seals and kelp gulls was more similar to that of control soils (i.e. soils without visible presence of plants or animals), which may be due to the more active behaviour of these marine animals compared to other species. Conversely, the soils from concentrations of southern elephant seals and penguins showed greater differences in soil nutrients compared to the control. In agreement with this, the bacterial communities of the soils associated with these animals were most different from those of the control soils, with the soils of penguin colonies also possessing the lowest bacterial diversity. However, all the soils influenced by the presence of marine animals were dominated by bacteria belonging to Gammaproteobacteria, particularly those of the genus Rhodanobacter. Therefore, we conclude that the modification of soil nutrient composition by marine vertebrates promotes specific groups of bacteria, which could play an important role in the recycling of nutrients in terrestrial Antarctic ecosystems.}, }
@article {pmid30625112, year = {2019}, author = {Brooks, LE and Kaze, M and Sistrom, M}, title = {Where the plasmids roam: large-scale sequence analysis reveals plasmids with large host ranges.}, journal = {Microbial genomics}, volume = {5}, number = {1}, pages = {}, doi = {10.1099/mgen.0.000244}, pmid = {30625112}, issn = {2057-5858}, abstract = {Describing the role of plasmids and their contribution to the exchange of genetic material among bacteria is essential for understanding the fields of plasmid epidemiology, microbial ecology, and commercial and synthetic microbiology. Broad-host-range (BHR) plasmids are those that are found not only in a single bacterial species, but in members of different taxonomic groups and are of significant interest to researchers in many fields. We applied a novel approach to computationally identify new BHR plasmids, in which we searched for highly similar cognate plasmids within a comprehensive plasmid database. After identifying 125 plasmid groups with highly similar cognates found in multiple taxa, we closely examined BHR plasmids found in multiple families. The majority of our identified BHR plasmids are found in members of the Enterobacteriaceae and closely related taxa, while three BHR plasmids of potential commercial significance were found in two species of Cyanobacteria. One plasmid with an exceptionally broad host range was found in both Gram-positive and Gram-negative bacterial species. This analysis demonstrates the utility of this method in identifying new BHR plasmids while highlighting unknown ranges of previously documented plasmids.}, }
@article {pmid30625109, year = {2019}, author = {van der Aart, LT and Nouioui, I and Kloosterman, A and Igual, JM and Willemse, J and Goodfellow, M and van Wezel, GP}, title = {Polyphasic classification of the gifted natural product producer Streptomyces roseifaciens sp. nov.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {69}, number = {4}, pages = {899-908}, doi = {10.1099/ijsem.0.003215}, pmid = {30625109}, issn = {1466-5034}, mesh = {Bacterial Typing Techniques ; Base Composition ; Biological Products ; China ; DNA, Bacterial/genetics ; Fatty Acids/chemistry ; Genes, Bacterial ; Multilocus Sequence Typing ; Nucleic Acid Hybridization ; Phospholipids/chemistry ; *Phylogeny ; Pigmentation ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Soil Microbiology ; Streptomyces/*classification/isolation &amp; purification ; Vitamin K 2/analogs &amp; derivatives/chemistry ; }, abstract = {A polyphasic study was designed to establish the taxonomic status of a Streptomyces strain isolated from soil from the QinLing Mountains, Shaanxi Province, China, and found to be the source of known and new specialized metabolites. Strain MBT76T was found to have chemotaxonomic, cultural and morphological properties consistent with its classification in the genus Streptomyces. The strain formed a distinct branch in the Streptomyces16S rRNA gene tree and was closely related to the type strains of Streptomyces hiroshimensis and Streptomycesmobaraerensis. Multi-locus sequence analyses based on five conserved house-keeping gene alleles showed that strain MBT76T is closely related to the type strain of S. hiroshimensis, as was the case in analysis of a family of conserved proteins. The organism was also distinguished from S. hiroshimensis using cultural and phenotypic features. Average nucleotide identity and digital DNA-DNA hybridization values between the genomes of strain MBT76T and S. hiroshimensis DSM 40037T were 88.96 and 28.4±2.3%, respectively, which is in line with their assignment to different species. On the basis of this wealth of data it is proposed that strain MBT76T (=DSM 106196T=NCCB 100637T), be classified as a new species, Streptomycesroseifaciens sp. nov.}, }
@article {pmid30624643, year = {2019}, author = {Baldrian, P}, title = {The known and the unknown in soil microbial ecology.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {2}, pages = {}, doi = {10.1093/femsec/fiz005}, pmid = {30624643}, issn = {1574-6941}, abstract = {The methodical developments in the fields of molecular biology and analytical chemistry significantly increased the level of detail that we achieve when exploring soils and their microbial inhabitants. High-resolution description of microbial communities, detection of taxa with minor abundances, screening of gene expression or the detailed characterization of metabolomes are nowadays technically feasible. Despite all of this, our understanding of soil is limited in many ways. The imperfect tools to describe microbial communities and limited possibilities to assign traits to community members make it difficult to link microbes to functions. Also the analysis of processes exemplified by enzyme activity measurements is still imperfect. In the future, it is important to look at soil at a finer detail to obtain a better picture on the properties of individual microbes, their in situ interactions, metabolic rates and activity at a scale relevant to individual microbes. Scaling up is needed as well to get answers at ecosystem or biome levels and to enable global modelling. The recent development of novel tools including metabolomics, identification of genomes in metagenomics sequencing datasets or collection of trait data have the potential to bring soil ecology further. It will, however, always remain a highly demanding scientific discipline.}, }
@article {pmid30623643, year = {2019}, author = {Evert, C and Loesekann, T and Bhat, G and Shajahan, A and Sonon, R and Azadi, P and Hunter, RC}, title = {Generation of 13C-Labeled MUC5AC Mucin Oligosaccharides for Stable Isotope Probing of Host-Associated Microbial Communities.}, journal = {ACS infectious diseases}, volume = {5}, number = {3}, pages = {385-393}, doi = {10.1021/acsinfecdis.8b00296}, pmid = {30623643}, issn = {2373-8227}, support = {R01 HL136919/HL/NHLBI NIH HHS/United States ; }, abstract = {Stable isotope probing (SIP) has emerged as a powerful tool to address key questions about microbiota structure and function. To date, diverse isotopically labeled substrates have been used to characterize in situ growth activity of specific bacterial taxa and have revealed the flux of bioavailable substrates through microbial communities associated with health and disease. A major limitation to the growth of the field is the dearth of biologically relevant &quot;heavy&quot; labeled substrates. Mucin glycoproteins, for example, comprise an abundant source of carbon in the gut, oral cavity, respiratory tract, and other mucosal surfaces but are not commercially available. Here, we describe a method to incorporate a 13C-labeled monosaccharide into MUC5AC, a predominant mucin in both gastrointestinal and airway environments. Using the lung adenocarcinoma cell line, Calu-3, polarized cell cultures grown in 13C-labeled d-glucose resulted in liberal mucin production on the apical surface. Mucins were isolated by size-exclusion chromatography, and O-linked glycans were released by β-elimination, permethylated, and analyzed by electrospray ionization tandem mass spectrometry (ESI-MS/MS) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) techniques. We demonstrate a 98.7% incorporation of 13C in the heterogeneous O-linked oligosaccharides that make up >80% of mucin dry weight. These &quot;heavy&quot; labeled glycoproteins represent a valuable tool for probing in vivo activity of host-associated bacterial communities and their interactions with the mucosal barrier. The continued expansion of labeled substrates for use in SIP will eventually allow bacterial taxa that degrade host compounds to be identified, with long-term potential for improved health and disease management.}, }
@article {pmid30623212, year = {2019}, author = {de Sousa, AGG and Tomasino, MP and Duarte, P and Fernández-Méndez, M and Assmy, P and Ribeiro, H and Surkont, J and Leite, RB and Pereira-Leal, JB and Torgo, L and Magalhães, C}, title = {Diversity and Composition of Pelagic Prokaryotic and Protist Communities in a Thin Arctic Sea-Ice Regime.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-01314-2}, pmid = {30623212}, issn = {1432-184X}, support = {244646//Research Council of Norway/ ; NORTE-01-0145-FEDER-000031//Structured Program of R&amp;D&amp;I MarInfo/ ; Arktis 2030//Norwegian Ministries of Foreign Affairs and Climate and Environment/ ; NITROLIMIT - PTDC 2017 - PTDC/CTA-AMB/30997/2017//Funda??o para a Ci?ncia e a Tecnologia/ ; }, abstract = {One of the most prominent manifestations of climate change is the changing Arctic sea-ice regime with a reduction in the summer sea-ice extent and a shift from thicker, perennial multiyear ice towards thinner, first-year ice. These changes in the physical environment are likely to impact microbial communities, a key component of Arctic marine food webs and biogeochemical cycles. During the Norwegian young sea ICE expedition (N-ICE2015) north of Svalbard, seawater samples were collected at the surface (5 m), subsurface (20 or 50 m), and mesopelagic (250 m) depths on 9 March, 27 April, and 16 June 2015. In addition, several physical and biogeochemical data were recorded to contextualize the collected microbial communities. Through the massively parallel sequencing of the small subunit ribosomal RNA amplicon and metagenomic data, this work allows studying the Arctic's microbial community structure during the late winter to early summer transition. Results showed that, at compositional level, Alpha- (30.7%) and Gammaproteobacteria (28.6%) are the most frequent taxa across the prokaryotic N-ICE2015 collection, and also the most phylogenetically diverse. Winter to early summer trends were quite evident since there was a high relative abundance of thaumarchaeotes in the under-ice water column in late winter while this group was nearly absent during early summer. Moreover, the emergence of Flavobacteria and the SAR92 clade in early summer might be associated with the degradation of a spring bloom of Phaeocystis. High relative abundance of hydrocarbonoclastic bacteria, particularly Alcanivorax (54.3%) and Marinobacter (6.3%), was also found. Richness showed different patterns along the depth gradient for prokaryotic (highest at mesopelagic depth) and protistan communities (higher at subsurface depths). The microbial N-ICE2015 collection analyzed in the present study provides comprehensive new knowledge about the pelagic microbiota below drifting Arctic sea-ice. The higher microbial diversity found in late winter/early spring communities reinforces the need to continue with further studies to properly characterize the winter microbial communities under the pack-ice.}, }
@article {pmid30620427, year = {2019}, author = {Pasulka, A and Hu, SK and Countway, PD and Coyne, KJ and Cary, SC and Heidelberg, KB and Caron, DA}, title = {SSU-rRNA Gene Sequencing Survey of Benthic Microbial Eukaryotes from Guaymas Basin Hydrothermal Vent.}, journal = {The Journal of eukaryotic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/jeu.12711}, pmid = {30620427}, issn = {1550-7408}, abstract = {Microbial eukaryotes have important roles in marine food webs, but their diversity and activities in hydrothermal vent ecosystems are poorly characterized. In this study, we analyzed microbial eukaryotic communities associated with bacterial (Beggiatoa) mats in the 2,000 m deep-sea Guaymas Basin hydrothermal vent system using 18S rRNA gene high-throughput sequencing of the V4 region. We detected 6,954 distinct Operational Taxonomic Units (OTUs) across various mat systems. Of the sequences that aligned with known protistan phylotypes, most were affiliated with alveolates (especially dinoflagellates and ciliates) and cercozoans. OTU richness and community structure differed among sediment habitats (e.g. different mat types and cold sediments away from mats). Additionally, full-length 18S rRNA genes amplified and cloned from single cells revealed the identities of some of the most commonly encountered, active ciliates in this hydrothermal vent ecosystem. Observations and experiments were also conducted to demonstrate that ciliates were trophically active and ingesting fluorescent bacteria or Beggiatoa trichomes. Our work suggests that the active and diverse protistan community at the Guaymas Basin hydrothermal vent ecosystem likely consumes substantial amounts of bacterial biomass, and that the different habitats, often defined by distances of just a few 10s of cm, select for particular assemblages and levels of diversity.}, }
@article {pmid30619557, year = {2018}, author = {Duplouy, A and Minard, G and Lähteenaro, M and Rytteri, S and Saastamoinen, M}, title = {Silk properties and overwinter survival in gregarious butterfly larvae.}, journal = {Ecology and evolution}, volume = {8}, number = {24}, pages = {12443-12455}, doi = {10.1002/ece3.4595}, pmid = {30619557}, issn = {2045-7758}, abstract = {All organisms are challenged by encounters with parasites, which strongly select for efficient escape strategies in the host. The threat is especially high for gregarious species entering immobile periods, such as diapause. Larvae of the Glanville fritillary butterfly, Melitaea cinxia, spend the winter in diapause in groups of conspecifics each sheltered in a silk nest. Despite intensive monitoring of the population, we have little understanding of the ecological factors influencing larval survival over the winter in the field. We tested whether qualitative and quantitative properties of the silk nest contribute to larval survival over diapause. We used comparative proteomics, metabarcoding analyses, microscopic imaging, and in vitro experiments to compare protein composition of the silk, community composition of the silk-associated microbiota, and silk density from both wild-collected and laboratory-reared families, which survived or died in the field. Although most traits assessed varied across families, only silk density was correlated with overwinter survival in the field. The silk nest spun by gregarious larvae before the winter acts as an efficient breathable physical shield that positively affects larval survival during diapause. Such benefit may explain how this costly trait is conserved across populations of this butterfly species and potentially across other silk-spinning insect species.}, }
@article {pmid30619545, year = {2018}, author = {Alessi, AM and Redeker, KR and Chong, JPJ}, title = {A practical introduction to microbial molecular ecology through the use of isolation chips.}, journal = {Ecology and evolution}, volume = {8}, number = {24}, pages = {12286-12298}, doi = {10.1002/ece3.4748}, pmid = {30619545}, issn = {2045-7758}, abstract = {In the context of antimicrobial resistance as one of the most serious issues faced globally by health providers, we explored a practical introduction to molecular microbial ecology. We designed field work and practical experiments for third year members of a 4 year undergraduate Masters Program, in which the students employed traditional and novel isolation techniques to identify antimicrobial activities from soil dwelling microorganisms. Students gained experience in isolating DNA from complex microbial communities, amplifying 16S rRNA genes and applied richness/diversity indices as well as principal coordinate analyses to the interpretation of the data they obtained from high throughput sequencing. Our results confirmed that isolation chips facilitate the growth of a greater diversity and different species subset from the complex soil microorganism community than traditional plate spreading techniques. However, rarefaction of 16S rRNA amplicon sequencing data showed that the majority of observed species in soil remain unculturable by current methods. Based on the written reports produced by the students carrying out the work, we concluded that the described protocols are robust and informative, that these activities provide a good practical introduction to the theories and practice of molecular ecology and can be easily deployed to groups of six or more students in a cost-effective manner.}, }
@article {pmid30619197, year = {2018}, author = {Dyksma, S and Lenk, S and Sawicka, JE and Mußmann, M}, title = {Uncultured Gammaproteobacteria and Desulfobacteraceae Account for Major Acetate Assimilation in a Coastal Marine Sediment.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3124}, doi = {10.3389/fmicb.2018.03124}, pmid = {30619197}, issn = {1664-302X}, abstract = {Acetate is a key intermediate in anaerobic mineralization of organic matter in marine sediments. Its turnover is central to carbon cycling, however, the relative contribution of different microbial populations to acetate assimilation in marine sediments is unknown. To quantify acetate assimilation by in situ abundant bacterial populations, we incubated coastal marine sediments with 14C-labeled acetate and flow-sorted cells that had been labeled and identified by fluorescence in situ hybridization. Subsequently, scintillography determined the amount of 14C-acetate assimilated by distinct populations. This approach fostered a high-throughput quantification of acetate assimilation by phylogenetically identified populations. Acetate uptake was highest in the oxic-suboxic surface layer for all sorted bacterial populations, including deltaproteobacterial sulfate-reducing bacteria (SRB), which accounted for up to 32% of total bacterial acetate assimilation. We show that the family Desulfobulbaceae also assimilates acetate in marine sediments, while the more abundant Desulfobacteraceae dominated acetate assimilation despite lower uptake rates. Unexpectedly, members of Gammaproteobacteria accounted for the highest relative acetate assimilation in all sediment layers with up to 31-62% of total bacterial acetate uptake. We also show that acetate is used to build up storage compounds such as polyalkanoates. Together, our findings demonstrate that not only the usual suspects SRB but a diverse bacterial community may substantially contribute to acetate assimilation in marine sediments. This study highlights the importance of quantitative approaches to reveal the roles of distinct microbial populations in acetate turnover.}, }
@article {pmid30619181, year = {2018}, author = {Simonin, M and Cantarel, AAM and Crouzet, A and Gervaix, J and Martins, JMF and Richaume, A}, title = {Negative Effects of Copper Oxide Nanoparticles on Carbon and Nitrogen Cycle Microbial Activities in Contrasting Agricultural Soils and in Presence of Plants.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3102}, doi = {10.3389/fmicb.2018.03102}, pmid = {30619181}, issn = {1664-302X}, abstract = {Metal-oxide nanoparticles (NPs) such as copper oxide (CuO) NPs offer promising perspectives for the development of novel agro-chemical formulations of pesticides and fertilizers. However, their potential impact on agro-ecosystem functioning still remains to be investigated. Here, we assessed the impact of CuO-NPs (0.1, 1, and 100 mg/kg dry soil) on soil microbial activities involved in the carbon and nitrogen cycles in five contrasting agricultural soils in a microcosm experiment over 90 days. Additionally, in a pot experiment, we evaluated the influence of plant presence on the toxicity of CuO-NPs on soil microbial activities. CuO-NPs caused significant reductions of the three microbial activities measured (denitrification, nitrification, and soil respiration) at 100 mg/kg dry soil, but the low concentrations (0.1 and 1 mg/kg) had limited effects. We observed that denitrification was the most sensitive microbial activity to CuO-NPs in most soil types, while soil respiration and nitrification were mainly impacted in coarse soils with low organic matter content. Additionally, large decreases in heterotrophic microbial activities were observed in soils planted with wheat, even at 1 mg/kg for soil substrate-induced respiration, indicating that plant presence did not mitigate or compensate CuO-NP toxicity for microorganisms. These two experiments show that CuO-NPs can have detrimental effects on microbial activities in soils with contrasting physicochemical properties and previously exposed to various agricultural practices. Moreover, we observed that the negative effects of CuO-NPs increased over time, indicating that short-term studies (hours, days) may underestimate the risks posed by these contaminants in soils.}, }
@article {pmid30619134, year = {2018}, author = {Porcar, M and Louie, KB and Kosina, SM and Van Goethem, MW and Bowen, BP and Tanner, K and Northen, TR}, title = {Microbial Ecology on Solar Panels in Berkeley, CA, United States.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3043}, doi = {10.3389/fmicb.2018.03043}, pmid = {30619134}, issn = {1664-302X}, abstract = {Solar panels can be found practically all over the world and represent a standard surface that can be colonized by microbial communities that are resistant to harsh environmental conditions, including high irradiation, temperature fluctuations and desiccation. These properties make them not only ideal sources of stress-resistant bacteria, but also standard devices to study the microbial communities and their colonization process from different areas of Earth. We report here a comprehensive description of the microbial communities associated with solar panels in Berkeley, CA, United States. Cultivable bacteria were isolated to characterize their adhesive capabilities, and UV- and desiccation-resistance properties. Furthermore, a parallel culture-independent metagenomic and metabolomic approach has allowed us to gain insight on the taxonomic and functional nature of these communities. Metagenomic analysis was performed using the Illumina HiSeq2500 sequencing platform, revealing that the bacterial population of the Berkeley solar panels is composed mainly of Actinobacteria, Bacteroidetes and Proteobacteria, as well as lower amounts of Deinococcus-Thermus and Firmicutes. Furthermore, a clear predominance of Hymenobacter sp. was also observed. A functional analysis revealed that pathways involved in the persistence of microbes on solar panels (i.e., stress response, capsule development, and metabolite repair) and genes assigned to carotenoid biosynthesis were common to all metagenomes. On the other hand, genes involved in photosynthetic pathways and general autotrophic subsystems were rare, suggesting that these pathways are not critical for persistence on solar panels. Metabolomics was performed using a liquid chromatography tandem mass spectrometry (LC-MS/MS) approach. When comparing the metabolome of the solar panels from Berkeley and from Valencia (Spain), a very similar composition in polar metabolites could be observed, although some metabolites appeared to be differentially represented (for example, trigonelline, pantolactone and 5-valerolactone were more abundant in the samples from Valencia than in the ones from Berkeley). Furthermore, triglyceride metabolites were highly abundant in all the solar panel samples, and both locations displayed similar profiles. The comparison of the taxonomic profile of the Californian solar panels with those previously described in Spain revealed striking similarities, highlighting the central role of both selective pressures and the ubiquity of microbial populations in the colonization and establishment of microbial communities.}, }
@article {pmid30619117, year = {2018}, author = {López-García, A and Pineda-Quiroga, C and Atxaerandio, R and Pérez, A and Hernández, I and García-Rodríguez, A and González-Recio, O}, title = {Comparison of Mothur and QIIME for the Analysis of Rumen Microbiota Composition Based on 16S rRNA Amplicon Sequences.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3010}, doi = {10.3389/fmicb.2018.03010}, pmid = {30619117}, issn = {1664-302X}, abstract = {Background: Microbiome studies need to analyze massive sequencing data, which requires the use of sophisticated bioinformatics pipelines. Up to date, several tools are available, although the literature is scarce on studies that compare the performance of different bioinformatics pipelines on rumen microbiota when 16S rRNA amplicons are analyzed. The impact of the pipeline on the outcome of the results is also unknown, mainly in terms of the output from studies using these tools as an intermediate phenotype (pseudophenotypes). This study compares two commonly used software (Quantitative Insights Into Microbial Ecology) (QIIME) and mothur, and two microbial gene data bases (GreenGenes and SILVA) for 16S rRNA gene analysis, using metagenome read data collected from rumen content of a cohort of dairy cows. Results: We compared the relative abundance (RA) of the identified OTUs at the genus level. Both tools presented a high degree of agreement at identifying the most abundant genera: Bifidobacterium, Butyrivibrio, Methanobrevibacter, Prevotella, and Succiniclasticum (RA > 1%), regardless the database. There were no statistical differences between mothur and QIIME (P > 0.05) at estimating the overall RA of the most abundant (RA > 10%) genera, either using SILVA or GreenGenes. However, differences were found at RA < 10% (P < 0.05) when using GreenGenes as database, with mothur assigning OTUs to a larger number of genera and in larger RA for these less frequent microorganisms. With this database mothur resulted in larger richness (P < 0.05), more favorable rarefaction curves and a larger analytic sensitivity. These differences caused significant and relevant differences between tools at identifying the dissimilarity of microbiotas between pairs of animals. However, these differences were attenuated, but not erased, when SILVA was used as the reference database. Conclusion: The findings showed that the SILVA database seemed a preferred reference dataset for classifying OTUs from rumen microbiota. If this database was used, both QIIME and mothur produced comparable richness and diversity, and also in the RA of most common rumen microbes. However, important differences were found for less common microorganisms which impacted on the beta diversity calculated between pipelines. This may have relevant implications at studying global rumen microbiota.}, }
@article {pmid30618066, year = {2019}, author = {Flores-Uribe, J and Hevroni, G and Ghai, R and Pushkarev, A and Inoue, K and Kandori, H and Béjà, O}, title = {Heliorhodopsins are absent in diderm (Gram-negative) bacteria: Some thoughts and possible implications for activity.}, journal = {Environmental microbiology reports}, volume = {11}, number = {3}, pages = {419-424}, doi = {10.1111/1758-2229.12730}, pmid = {30618066}, issn = {1758-2229}, support = {545/17//Israel Science Foundation/ ; }, abstract = {Microbial heliorhodopsins are a new type of rhodopsins, currently believed to engage in light sensing, with an opposite membrane topology compared to type-1 and type-2 rhodopsins. We determined heliorhodopsins presence/absence is monoderms and diderms representatives from the Tara Oceans and freshwater metagenomes as well as metagenome assembled genome collections. Heliorhodopsins are absent in diderms, confirming our previous observations in cultured Proteobacteria. We do not rule out the possibility that heliorhodopsins serve as light sensors. However, this does not easily explain their absence from diderms. Based on these observations, we speculate on the putative role of heliorhodopsins in light-driven transport of amphiphilic molecules.}, }
@article {pmid30613848, year = {2019}, author = {Ye, S and Bhattacharjee, M and Siemann, E}, title = {Thermal Tolerance in Green Hydra: Identifying the Roles of Algal Endosymbionts and Hosts in a Freshwater Holobiont Under Stress.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {537-545}, doi = {10.1007/s00248-018-01315-1}, pmid = {30613848}, issn = {1432-184X}, mesh = {Animals ; Chlorophyta/*physiology ; Fresh Water/chemistry/parasitology ; Hot Temperature ; Hydra/*parasitology/physiology ; Stress, Physiological ; *Symbiosis ; }, abstract = {It has been proposed that holobionts (host-symbiont units) could swap endosymbionts, rapidly alter the hologenome (host plus symbiont genome), and increase their stress tolerance. However, experimental tests of individual and combined contributions of hosts and endosymbionts to holobiont stress tolerance are needed to test this hypothesis. Here, we used six green hydra (Hydra viridissima) strains to tease apart host (hydra) and symbiont (algae) contributions to thermal tolerance. Heat shock experiments with (1) hydra with their original symbionts, (2) aposymbiotic hydra (algae removed), (3) novel associations (a single hydra strain hosting different algae individually), and (4) control hydra (aposymbiotic hydra re-associated with their original algae) showed high variation in thermal tolerance in each group. Relative tolerances of strains were the same within original, aposymbiotic, and control treatments, but reversed in the novel associations group. Aposymbiotic hydra had similar or higher thermal tolerance than hydra with algal symbionts. Selection on the holobiont appears to be stronger than on either partner alone, suggesting endosymbiosis could become an evolutionary trap under climate change. Our results suggest that green hydra thermal tolerance is strongly determined by the host, with a smaller, non-positive role for the algal symbiont. Once temperatures exceed host tolerance limits, swapping symbionts is unlikely to allow these holobionts to persist. Rather, increases in host tolerance through in situ adaptation or migration of pre-adapted host strains appear more likely to increase local thermal tolerance. Overall, our results indicate green hydra is a valuable system for studying aquatic endosymbiosis under changing environmental conditions, and demonstrate how the host and the endosymbiont contribute to holobiont stress tolerance.}, }
@article {pmid30612185, year = {2019}, author = {Murphy, AE and Kolkmeyer, R and Song, B and Anderson, IC and Bowen, J}, title = {Bioreactivity and Microbiome of Biodeposits from Filter-Feeding Bivalves.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {343-357}, doi = {10.1007/s00248-018-01312-4}, pmid = {30612185}, issn = {1432-184X}, support = {OCE 1062882//National Science Foundation/ ; OCE 1233801//National Science Foundation/ ; LTER 0080381//National Science Foundation/ ; NA10OAR4170085//Virginia Sea Grant, Virginia Institute of Marine Science/ ; }, mesh = {Ammonium Compounds/metabolism ; Animals ; Bacteria/classification/genetics/*isolation &amp; purification/metabolism ; Bivalvia/metabolism/*microbiology ; Carbon/metabolism ; Crassostrea/metabolism/microbiology ; Eutrophication ; Geologic Sediments/chemistry/microbiology ; Mercenaria/metabolism/microbiology ; *Microbiota ; Phylogeny ; Seawater/chemistry/microbiology ; }, abstract = {Bivalves serve an important ecosystem function in delivering organic matter from pelagic to benthic zones and are important in mediating eutrophication. However, the fate of this organic matter (i.e., biodeposits) is an important consideration when assessing the ecological roles of these organisms in coastal ecosystems. In addition to environmental conditions, the processing of biodeposits is dependent on its composition and the metabolic capacity of the associated microbial community. The objectives of this study were to compare the biological reactivity, potential denitrification rates, and microbial communities of biodeposits sourced from different bivalve species: hard clam (Mercenaria mercenaria), eastern oyster (Crassostrea virginica), and ribbed mussel (Geukensia demissa). To our knowledge, this is the first study to investigate and compare the microbiome of bivalve biodeposits using high-throughput sequencing and provide important insight into the mechanisms by which bivalves may alter sediment microbial communities and benthic biogeochemical cycles. We show that clam biodeposits had significantly higher bioreactivity compared to mussel and oyster biodeposits, as reflected in higher dissolved inorganic carbon and ammonium production rates in controlled incubations. Potential denitrification rates were also significantly higher for clam biodeposits compared to oyster and mussel biodeposits. The microbial communities associated with the biodeposits were significantly different across bivalve species, with significantly greater abundances of Alteromonadales, Chitinophagales, Rhodobacterales, and Thiotrichales associated with the clam biodeposits. These bioreactivity and microbial differences across bivalve species are likely due to differences in bivalve physiology and feeding behavior and should be considered when evaluating the effects of bivalves on water quality and ecosystem function.}, }
@article {pmid30612184, year = {2019}, author = {Pan, J and Chen, Y and Wang, Y and Zhou, Z and Li, M}, title = {Vertical Distribution of Bathyarchaeotal Communities in Mangrove Wetlands Suggests Distinct Niche Preference of Bathyarchaeota Subgroup 6.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {417-428}, doi = {10.1007/s00248-018-1309-7}, pmid = {30612184}, issn = {1432-184X}, support = {41506163,31622002,91851105//National Natural Science Foundation of China/ ; 31600093//National Natural Science Foundation of China/ ; }, mesh = {Archaea/classification/genetics/*isolation &amp; purification ; *Biodiversity ; Carbon Cycle ; DNA, Archaeal/genetics ; Geologic Sediments/analysis/microbiology ; High-Throughput Nucleotide Sequencing ; Lakes/analysis/microbiology ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/analysis/microbiology ; Wetlands ; }, abstract = {Bathyarchaeota is a diverse, abundant, and widespread archaeal phylum that may play an important role in global carbon cycling. The vertical distribution of Bathyarchaeota and environmental impact on bathyarchaeotal community in deep-sea and lake sediments are known; however, little information is available on Bathyarchaeota in eutrophic and brackish environments, such as mangrove wetlands. In the current study, we investigated the bathyarchaeotal community in the mangrove ecosystem of Futian Nature Reserve, Shenzhen. By slicing the profile into 2-cm layers from the surface to bottom, 110 sediment samples were obtained from three mangrove and three mud flat profiles. High-throughput sequencing of archaeal 16S rRNA genes, quantification of bathyarchaeotal 16S rRNA genes with optimized quantitative primers, and the ensuing statistical analyses revealed the vertical distribution of Bathyarchaeota in the mangrove ecosystem, indicating that Bathyarchaeota was the dominant archaeal phylum therein, with Bathyarchaeota subgroups 6, 8, 15, and 17 as the most abundant subgroups. The abundance of Bathyarchaeota was higher in the mangrove than in the mud flat and other oligotrophic or freshwater habitats. Total organic carbon (TOC) and nitric oxide were significantly correlated with the abundance of Bathyarchaeota, and pH was the major factor shaping the community composition. Further, the data suggested that Bathyarchaeota subgroup 6 preferentially dwelled in slightly acidic, high TOC, and subsurface environments, indicating a potentially distinct role in the global geochemical cycle. These findings expand the knowledge of the distribution and niche preference of Bathyarchaeota, emphasizing the need for continuous characterization of bathyarchaeotal subgroups.}, }
@article {pmid30612183, year = {2019}, author = {Ding, W and Zhang, W and Alikunhi, NM and Batang, Z and Pei, B and Wang, R and Chen, L and Al-Suwailem, A and Qian, PY}, title = {Metagenomic Analysis of Zinc Surface-Associated Marine Biofilms.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {406-416}, doi = {10.1007/s00248-018-01313-3}, pmid = {30612183}, issn = {1432-184X}, mesh = {Bacteria/classification/*genetics/isolation &amp; purification ; Bacterial Physiological Phenomena ; Biodiversity ; *Biofilms ; Indian Ocean ; Metagenomics ; Phylogeny ; Seawater/analysis/*microbiology ; Zinc/analysis/*metabolism ; }, abstract = {Biofilms are a significant source of marine biofouling. Marine biofilm communities are established when microorganisms adhere to immersed surfaces. Despite the microbe-inhibiting effect of zinc surfaces, microbes can still attach to the surface and form biofilms. However, the diversity of biofilm-forming microbes that can attach to zinc surfaces and their common functional features remain elusive. Here, by analyzing 9,000,000 16S rRNA gene amplicon sequences and 270 Gb of metagenomic data, we comprehensively explored the taxa and functions related to biofilm formation in subtidal zones of the Red Sea. A clear difference was observed between the biofilm and adjacent seawater microbial communities in terms of the taxonomic structure at phylum and genus levels, and a huge number of genera were only present in the biofilms. Saturated alpha-diversity curves suggested the existence of more than 14,000 operational taxonomic units in one biofilm sample, which is much higher than previous estimates. Remarkably, the biofilms contained abundant and diverse transposase genes, which were localized along microbial chromosomal segments and co-existed with genes related to metal ion transport and resistance. Genomic analyses of two cyanobacterial strains that were abundant in the biofilms revealed a variety of metal ion transporters and transposases. Our analyses revealed the high diversity of biofilm-forming microbes that can attach to zinc surfaces and the ubiquitous role of transposase genes in microbial adaptation to toxic metal surfaces.}, }
@article {pmid30612083, year = {2019}, author = {Zhu, X and Campanaro, S and Treu, L and Kougias, PG and Angelidaki, I}, title = {Novel ecological insights and functional roles during anaerobic digestion of saccharides unveiled by genome-centric metagenomics.}, journal = {Water research}, volume = {151}, number = {}, pages = {271-279}, doi = {10.1016/j.watres.2018.12.041}, pmid = {30612083}, issn = {1879-2448}, abstract = {In typical anaerobic digestion (AD) systems, the microbial functional assertion is hampered by synchronised versatile metabolism required for heterogeneous substrates degradation. Thus, the intricate methanogenic process from organic compounds remains an enigma after decades of empirical operation. In this study, simplified AD microbial communities were obtained with substrate specifications and continuous reactor operation. Genome-centric metagenomic approach was followed to holistically investigate the metabolic pathways of the AD and the microbial synergistic networks. In total, 63 metagenome assembled genomes (MAGs) were assembled from 8 metagenomes acquired in specific methanogenic niches. The metabolic pathways were reconstructed from the annotated genes and their dynamicity under experimental conditions. The results show that the methanogenic niches nourish unique metabolism beyond current knowledge acquired from cultivation-based methods. A novel glucose mineralization model without acetate formation was proposed and asserted in a pair of syntrophs: Clostridiaceae sp. and Methanoculleus thermophilus. Moreover, the catabolic pathway was elucidated in uncharacterized syntrophic acetate oxidizers, Synergistaceae spp. A remarkable evolutionary insight is the discovery that electron transport and energy conservation mechanisms impose selective pressure on syntrophic partners. Overall, the functional roles of the individual microbes tightly rely on the catabolic pathways and cannot always be physiologically defined in accordance with conventional four-step AD concept. The substrate-specific systems provided a traceable microbial community to dissecting the AD process. The genome-centric metagenomics successfully constructed genomes of microbes that have not been previously isolated and illustrated metabolic pathways that beyond the current knowledge of AD process. This study provides new perspectives to unravel the AD microbial ecology and suggests more attention should be paid on uncharacterized metabolism specifically harboured by AD microbial communities.}, }
@article {pmid30610256, year = {2019}, author = {Mikhailov, IS and Zakharova, YR and Bukin, YS and Galachyants, YP and Petrova, DP and Sakirko, MV and Likhoshway, YV}, title = {Correction to: Co-occurrence Networks Among Bacteria and Microbial Eukaryotes of Lake Baikal During a Spring Phytoplankton Bloom.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {558}, doi = {10.1007/s00248-018-1307-9}, pmid = {30610256}, issn = {1432-184X}, abstract = {The original version of this article unfortunately contained mistakes in the legends of figures.}, }
@article {pmid30610255, year = {2019}, author = {Xia, X and Cheung, S and Endo, H and Suzuki, K and Liu, H}, title = {Latitudinal and Vertical Variation of Synechococcus Assemblage Composition Along 170° W Transect From the South Pacific to the Arctic Ocean.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {333-342}, doi = {10.1007/s00248-018-1308-8}, pmid = {30610255}, issn = {1432-184X}, support = {JPMJCR11A5//JST CREST program/ ; 24121004//JSPS Grant-in-Aid for Scientific Research on Innovative Areas/ ; 16128416 and 16101917//Research Grant Council of Hong Kong/ ; }, mesh = {Arctic Regions ; Biodiversity ; Pacific Ocean ; Phylogeny ; Seawater/chemistry/*microbiology ; Synechococcus/*classification/genetics/*isolation &amp; purification ; Temperature ; }, abstract = {Synechococcus is one of the most widely distributed and abundant picocyanobacteria in the global oceans. Although latitudinal variation of Synechococcus assemblage in marine surface waters has been observed, few studies compared Synechococcus assemblage composition in surface and subsurface waters at the basin scale. Here, we report marine Synechococcus diversity in the surface and deep chlorophyll maximum (DCM) layers along 170° W from the South Pacific to the Arctic Ocean in summer. Along the transect, spatial niche partitioning of Synechococcus lineages in the surface waters was clearly observed. Species richness of surface Synechococcus assemblage was positively correlated with water temperature. Clade CRD1 was dominant in the areas (15° S-10° N and 35-40° N) associated with upwelling, and there were 3 different subclades with distinct distribution. CRD1-A was restricted in the North Equatorial Current (5-10° N), CRD1-B dominated in the equatorial upwelling region (15° S-0.17° N), and CRD1-C was only distributed in the North Pacific Current (35-40° N). Similarities between the Synechococcus assemblages in the surface and DCM layers were high at the upwelling regions and areas where the mixed layer was deep, while low in the Subtropical Gyres with strong stratification. Clade I, CRD1-B, and CRD1-C were major Synechococcus lineages in the DCM layer. In particular, clade I, which is composed of 7 subclades with distinct thermal niches, was widely distributed in the DCM layer. Overall, our results provide new insights into not only the latitudinal distribution of Synechococcus assemblages, but also their vertical variation in the central Pacific.}, }
@article {pmid30610231, year = {2019}, author = {Andrei, AŞ and Salcher, MM and Mehrshad, M and Rychtecký, P and Znachor, P and Ghai, R}, title = {Niche-directed evolution modulates genome architecture in freshwater Planctomycetes.}, journal = {The ISME journal}, volume = {13}, number = {4}, pages = {1056-1071}, doi = {10.1038/s41396-018-0332-5}, pmid = {30610231}, issn = {1751-7370}, support = {MSM200961801//Akademie Věd České Republiky (Academy of Sciences of the Czech Republic)/ ; PPPLZ: L200961651//Akademie Věd České Republiky (Academy of Sciences of the Czech Republic)/ ; 17-04828S//Grantová Agentura České Republiky (Grant Agency of the Czech Republic)/ ; 17-04828S//Grantová Agentura České Republiky (Grant Agency of the Czech Republic)/ ; }, abstract = {Freshwater environments teem with microbes that do not have counterparts in culture collections or genetic data available in genomic repositories. Currently, our apprehension of evolutionary ecology of freshwater bacteria is hampered by the difficulty to establish organism models for the most representative clades. To circumvent the bottlenecks inherent to the cultivation-based techniques, we applied ecogenomics approaches in order to unravel the evolutionary history and the processes that drive genome architecture in hallmark freshwater lineages from the phylum Planctomycetes. The evolutionary history inferences showed that sediment/soil Planctomycetes transitioned to aquatic environments, where they gave rise to new freshwater-specific clades. The most abundant lineage was found to have the most specialised lifestyle (increased regulatory genetic circuits, metabolism tuned for mineralization of proteinaceous sinking aggregates, psychrotrophic behaviour) within the analysed clades and to harbour the smallest freshwater Planctomycetes genomes, highlighting a genomic architecture shaped by niche-directed evolution (through loss of functions and pathways not needed in the newly acquired freshwater niche).}, }
@article {pmid30607437, year = {2019}, author = {Lupatini, M and Suleiman, AKA and Jacques, RJS and Lemos, LN and Pylro, VS and Van Veen, JA and Kuramae, EE and Roesch, LFW}, title = {Moisture Is More Important than Temperature for Assembly of Both Potentially Active and Whole Prokaryotic Communities in Subtropical Grassland.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {460-470}, doi = {10.1007/s00248-018-1310-1}, pmid = {30607437}, issn = {1432-184X}, mesh = {Bacteria/classification/genetics/*isolation &amp; purification ; Biodiversity ; DNA, Bacterial/genetics ; Grassland ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Soil/*chemistry ; *Soil Microbiology ; Temperature ; Water/*analysis/metabolism ; }, abstract = {Moisture and temperature play important roles in the assembly and functioning of prokaryotic communities in soil. However, how moisture and temperature regulate the function of niche- versus neutral-based processes during the assembly of these communities has not been examined considering both the total microbial community and the sole active portion with potential for growth in native subtropical grassland. We set up a well-controlled microcosm-based experiment to investigate the individual and combined effects of moisture and temperature on soil prokaryotic communities by simulating subtropical seasons in grassland. The prokaryotic populations with potential for growth and the total prokaryotic community were assessed by 16S rRNA transcript and 16S rRNA gene analyses, respectively. Moisture was the major factor influencing community diversity and structure, with a considerable effect of this factor on the total community. The prokaryotic populations with potential for growth and the total communities were influenced by the same assembly rules, with the niche-based mechanism being more influential in communities under dry condition. Our results provide new information regarding moisture and temperature in microbial communities of soil and elucidate how coexisting prokaryotic populations, under different physiological statuses, are shaped in native subtropical grassland soil.}, }
@article {pmid30604790, year = {2019}, author = {De Paepe, K and Verspreet, J and Rezaei, MN and Martinez, SH and Meysman, F and Van de Walle, D and Dewettinck, K and Courtin, CM and Van de Wiele, T}, title = {Modification of wheat bran particle size and tissue composition affects colonisation and metabolism by human faecal microbiota.}, journal = {Food &amp; function}, volume = {10}, number = {1}, pages = {379-396}, doi = {10.1039/c8fo01272e}, pmid = {30604790}, issn = {2042-650X}, mesh = {Adult ; Bacteria/classification/genetics/growth &amp; development/*metabolism ; Dietary Fiber/analysis/*metabolism ; Fatty Acids, Volatile/metabolism ; Feces/*microbiology ; Female ; *Gastrointestinal Microbiome ; Humans ; Male ; Particle Size ; Triticum/chemistry/*metabolism ; Young Adult ; }, abstract = {Dietary modulation can alter the gut microbiota composition and activity, in turn affecting health. Particularly, dietary fibre rich foods, such as wheat bran, are an important nutrient source for the gut microbiota. Several processing methods have been developed to modify the functional, textural and breadmaking properties of wheat bran, which can affect the gut microbiota. We therefore studied the effect of enzyme treatment, particle size reduction and wheat kernel pearling on the faecal microbiota of ten healthy individuals. The most commonly studied health marker, associated to the gut microbiota activity is Short Chain Fatty Acid (SCFA) production. This study shows that modifying wheat bran physicochemical properties allows control over the extent and the rate of SCFA production by the faecal microbiota. Wheat bran pericarp fractions, depleted in starch and enriched in cellulose and highly branched arabinoxylans, were poorly fermentable compared to unmodified wheat bran, thus resulting in a reduced SCFA production with up to 20 mM. The nature of the SCFA, however, largely depends on the donor and can be linked to the individual's gut microbiota composition. The latter changed in an individually dependent manner in response to wheat bran modification. Some product dependent significant differences could still be identified across the ten donors. This product effect is more pronounced in the microbial community attached to the wheat bran residue as compared to the luminal microbial community. Generally, we find lower levels of Firmicutes, Bacteroidetes and Bifidobacterium and a higher abundance of Proteobacteria in the pericarp enriched wheat bran fractions, compared to unmodified wheat bran.}, }
@article {pmid30603770, year = {2019}, author = {Ishizawa, H and Kuroda, M and Inoue, K and Inoue, D and Morikawa, M and Ike, M}, title = {Colonization and Competition Dynamics of Plant Growth-Promoting/Inhibiting Bacteria in the Phytosphere of the Duckweed Lemna minor.}, journal = {Microbial ecology}, volume = {77}, number = {2}, pages = {440-450}, doi = {10.1007/s00248-018-1306-x}, pmid = {30603770}, issn = {1432-184X}, support = {JPJMAL1108//Advanced Low Carbon Technology Research and Development Program/ ; JP18J10181//Japan Society for the Promotion of Science/ ; }, mesh = {Agricultural Inoculants/classification/genetics/growth &amp; development/*isolation &amp; purification ; Araceae/*growth &amp; development/microbiology ; Bacteria/classification/genetics/growth &amp; development/*isolation &amp; purification ; Biodiversity ; Plant Roots/growth &amp; development/*microbiology ; }, abstract = {Despite the considerable role of aquatic plant-associated bacteria in host plant growth and nutrient cycling in aquatic environments, the mode of their plant colonization has hardly been understood. This study examined the colonization and competition dynamics of a plant growth-promoting bacterium (PGPB) and two plant growth-inhibiting bacteria (PGIB) in the aquatic plant Lemna minor (common duckweed). When inoculated separately to L. minor, each bacterial strain quickly colonized at approximately 106 cells per milligram (plant fresh weight) and kept similar populations throughout the 7-day cultivation time. The results of two-membered co-inoculation assays revealed that the PGPB strain Aquitalea magnusonii H3 consistently competitively excluded the PGIB strain Acinetobacter ursingii M3, and strain H3 co-existed at almost 1:1 proportion with another PGIB strain, Asticcacaulis excentricus M6, regardless of the inoculation ratios (99:1-1:99) and inoculation order. We also found that A. magnusonii H3 exerted its growth-promoting effect over the negative effects of the two PGIB strains even when only a small amount was inoculated, probably due to its excellent competitive colonization ability. These experimental results demonstrate that there is a constant ecological equilibrium state involved in the bacterial colonization of aquatic plants.}, }
@article {pmid30603713, year = {2018}, author = {Nakato, GV and Wicker, E and Coutinho, TA and Mahuku, G and Studholme, DJ}, title = {A highly specific tool for identification of Xanthomonas vasicola pv. musacearum based on five Xvm-specific coding sequences.}, journal = {Heliyon}, volume = {4}, number = {12}, pages = {e01080}, doi = {10.1016/j.heliyon.2018.e01080}, pmid = {30603713}, issn = {2405-8440}, abstract = {Xanthomonas vasicola pv. musacearum (Xvm) is a bacterial pathogen responsible for the economically important Xanthomonas wilt disease on banana and enset crops in Sub-Saharan Africa. Given that the symptoms are similar to those of other diseases, molecular diagnosis is essential to unambiguously identify this pathogen and distinguish it from closely related strains not pathogenic on these hosts. Currently, Xvm identification is based on polymerase chain reaction (PCR) with GspDm primers, targeting the gene encoding general secretory protein D. Experimental results and examination of genomic sequences revealed poor specificity of the GspDm PCR. Here, we present and validate five new Xvm-specific primers amplifying only Xvm strains.}, }
@article {pmid30602082, year = {2018}, author = {Jeon, SJ and Galvão, KN}, title = {An Advanced Understanding of Uterine Microbial Ecology Associated with Metritis in Dairy Cows.}, journal = {Genomics &amp; informatics}, volume = {16}, number = {4}, pages = {e21}, doi = {10.5808/GI.2018.16.4.e21}, pmid = {30602082}, issn = {1598-866X}, abstract = {Metritis, the inflammation of the uterus caused by polymicrobial infections, is a prevalent and costly disease to the dairy industry as it decreases milk yield, survival, and the welfare of dairy cows. Although the antibiotic ceftiofur is widely used for the treatment of metritis, endometrium and ovary function is compromised, resulting in subfertility and infertility. According to culture-dependent studies, uterine pathogens include Escherichia coli, Trueperella pyogenes, Fusobacterium necrophorum, and Prevotella melaninogenica. Recent studies using high-throughput sequencing claimed that metritis is a microbiota-associated disease. Herein, we propose that metritis is associated with uterine microbiota with high abundance of Bacteroides, Porphyromonas, and Fusobacterium, but rare bacteria such as Escherichia coli and Helcococcus ovis cannot be ignored.}, }
@article {pmid30599206, year = {2019}, author = {Zwaenepoel, A and Li, Z and Lohaus, R and Van de Peer, Y}, title = {Finding Evidence for Whole Genome Duplications: A Reappraisal.}, journal = {Molecular plant}, volume = {12}, number = {2}, pages = {133-136}, doi = {10.1016/j.molp.2018.12.019}, pmid = {30599206}, issn = {1752-9867}, }
@article {pmid30598728, year = {2019}, author = {Rafeek, R and Carrington, CVF and Gomez, A and Harkins, D and Torralba, M and Kuelbs, C and Addae, J and Moustafa, A and Nelson, KE}, title = {Xylitol and sorbitol effects on the microbiome of saliva and plaque.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1536181}, doi = {10.1080/20002297.2018.1536181}, pmid = {30598728}, issn = {2000-2297}, abstract = {Chewing gum containing xylitol may help prevent caries by reducing levels of mutans streptococci (MS) and lactobacilli in saliva and plaque. Very little is known about other species which are possibly beneficial to oral health. In this study, we employed high-throughput sequencing of the 16S rRNA gene to profile microbial communities of saliva and plaque following short-term consumption of xylitol and sorbitol containing chewing gum. Participants (n = 30) underwent a washout period and were randomly assigned to one of two groups. Each group chewed either xylitol or sorbitol gum for three weeks, before undergoing a second four-week washout period after which they switched to the alternate gum for three weeks. Analysis of samples collected before and after each intervention identified distinct plaque and saliva microbial communities that altered dependent on the order in which gum treatments were given. Neither the xylitol nor sorbitol treatments significantly affected the bacterial composition of plaque. Lactobacilli were undetected and the number of Streptococcus mutans sequence reads was very low and unaffected by either xylitol or sorbitol. However, sorbitol affected several other streptococcal species in saliva including increasing the abundance of S. cristatus, an oral commensal shown to inhibit bacteria associated with chronic periodontitis.}, }
@article {pmid30595029, year = {2019}, author = {Tian, L and Tan, Y and Chen, G and Wang, G and Sun, J and Ou, S and Chen, W and Bai, W}, title = {Metabolism of anthocyanins and consequent effects on the gut microbiota.}, journal = {Critical reviews in food science and nutrition}, volume = {59}, number = {6}, pages = {982-991}, doi = {10.1080/10408398.2018.1533517}, pmid = {30595029}, issn = {1549-7852}, abstract = {Anthocyanins are natural water-soluble polyphenols present in fruits and vegetables. Health-promoting effects attributed to anthocyanins are mainly associated with oxidative stress inhibition and gut microbiota modulation. Dietary anthocyanins undergo a complex metabolism after ingestion and interact with endogenous and microbial enzymes, leading to the production of a large number of circulating and excreted anthocyanin metabolites and catabolic products. To date, the bioavailability and health benefits of anthocyanins have been widely documented. Although there are several papers that illustrated the metabolism of anthocyanins, the effects of dietary anthocyanins on the modulation of the gut microbial ecology and on the growth of certain microbial species are still poorly understood. The present paper summarizes the recent data on the absorption of anthocyanins in the upper gastrointestine and the metabolism of anthocyanins by gut microbiota. The modulatory effects of anthocyanins from different sources on gut microbiota are also discussed.}, }
@article {pmid30594092, year = {2019}, author = {Garner, E and Inyang, M and Garvey, E and Parks, J and Glover, C and Grimaldi, A and Dickenson, E and Sutherland, J and Salveson, A and Edwards, MA and Pruden, A}, title = {Impact of blending for direct potable reuse on premise plumbing microbial ecology and regrowth of opportunistic pathogens and antibiotic resistant bacteria.}, journal = {Water research}, volume = {151}, number = {}, pages = {75-86}, doi = {10.1016/j.watres.2018.12.003}, pmid = {30594092}, issn = {1879-2448}, abstract = {Little is known about how introducing recycled water intended for direct potable reuse (DPR) into distribution systems and premise plumbing will affect water quality at the point of use, particularly with respect to effects on microbial communities and regrowth. The examination of potential growth of opportunistic pathogens (OPs) and spread of antibiotic resistance genes (ARGs), each representing serious and growing public health concerns, by introducing DPR water has not previously been evaluated. In this study, the impact of blending purified DPR water with traditional drinking water sources was investigated with respect to treatment techniques, blending location, and blending ratio. Water from four U.S. utility partners was treated in bench- and pilot-scale treatment trains to simulate DPR with blending. Water was incubated in simulated premise plumbing rigs made of PVC pipe containing brass coupons to measure regrowth of total bacteria (16S rRNA genes, heterotrophic plate count), OPs (Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa), ARGs (qnrA, vanA), and an indicator of horizontal gene transfer and multi-drug resistance (intI1). The microbial community composition was profiled and the resistome (i.e., all ARGs present) was characterized in select samples using next generation sequencing. While regrowth of total bacteria (16S rRNA genes) from the start of the incubation through week eight consistently occurred across tested scenarios (Wilcoxon, p ≤ 0.0001), total bacteria were not more abundant in the water or biofilm of any DPR scenario than in the corresponding conventional potable condition (p ≥ 0.0748). Regrowth of OP marker genes, qnrA, vanA, and intI1 were not significantly greater in water or biofilm for any DPR blends treated with advanced oxidation compared to corresponding potable water (p ≥ 0.1047). This study of initial bacteria colonizing pipes after introduction of blended DPR water revealed little evidence (i.e., one target in one water type) of exacerbated regrowth of total bacteria, OPs, or ARGs in premise plumbing.}, }
@article {pmid30593603, year = {2018}, author = {Bachran, M and Kluge, S and Lopez-Fernandez, M and Cherkouk, A}, title = {Microbial Diversity in an Arid, Naturally Saline Environment.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1301-2}, pmid = {30593603}, issn = {1432-184X}, abstract = {The Arava Valley in is a rock desert within the Great African Rift valley. Soil from this area is covered with a salt crust. Here, we report microbial diversity from arid, naturally saline samples collected near Ein Yahav from the Arava Valley by culture-independent as well as culture-dependent analysis. High-throughput sequencing of the hypervariable region V4 of the 16S rRNA gene revealed that the microbial community consists of halophiles from the domain Bacteria as well as Archaea. Bacterial diversity was mainly represented by the genus Salinimicrobium of the order Flavobacteriales within the phylum Bacteroidetes, from the gammaproteobacterial orders Alteromonadales and Oceanospirillales as well as representatives from the order Bacillales of the phylum Firmicutes. Archaeal diversity was dominated by euryarchaeal Halobacteria from the orders Halobacteriales, Haloferacales, and Natrialbales. But more than 40% of the sequences affiliated with Archaea were assigned to unknown or unclassified archaea. Even if taxonomic resolution of the 16S rRNA gene V4 region for Archaea is limited, this study indicates the need of further and more detailed studies of Archaea. By using culture-dependent analysis, bacteria of the order Bacillales as well as archaea from all three halobacterial orders Halobacteriales, Haloferacales, and Natrialbales including potentially novel species from the genera Halorubrum and Haloparvum were isolated.}, }
@article {pmid30593565, year = {2019}, author = {Vallespir Lowery, N and Ursell, T}, title = {Structured environments fundamentally alter dynamics and stability of ecological communities.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {2}, pages = {379-388}, doi = {10.1073/pnas.1811887116}, pmid = {30593565}, issn = {1091-6490}, mesh = {*Computer Simulation ; Microbial Consortia/*physiology ; *Models, Biological ; }, abstract = {The dynamics and stability of ecological communities are intimately linked with the specific interactions-like cooperation or predation-between constituent species. In microbial communities, like those found in soils or the mammalian gut, physical anisotropies produced by fluid flow and chemical gradients impact community structure and ecological dynamics, even in structurally isotropic environments. Although natural communities existing in physically unstructured environments are rare, the role of environmental structure in determining community dynamics and stability remains poorly studied. To address this gap, we used modified Lotka-Volterra simulations of competitive microbial communities to characterize the effects of surface structure on community dynamics. We find that environmental structure has profound effects on communities, in a manner dependent on the specific pattern of interactions between community members. For two mutually competing species, eventual extinction of one competitor is effectively guaranteed in isotropic environments. However, addition of environmental structure enables long-term coexistence of both species via local &quot;pinning&quot; of competition interfaces, even when one species has a significant competitive advantage. In contrast, while three species competing in an intransitive loop (as in a game of rock-paper-scissors) coexist stably in isotropic environments, structural anisotropy disrupts the spatial patterns on which coexistence depends, causing chaotic population fluctuations and subsequent extinction cascades. These results indicate that the stability of microbial communities strongly depends on the structural environment in which they reside. Therefore, a more complete ecological understanding, including effective manipulation and interventions in natural communities of interest, must account for the physical structure of the environment.}, }
@article {pmid30586832, year = {2019}, author = {Yang, S and Zheng, Q and Yuan, M and Shi, Z and Chiariello, NR and Docherty, KM and Dong, S and Field, CB and Gu, Y and Gutknecht, J and Hungate, BA and Le Roux, X and Ma, X and Niboyet, A and Yuan, T and Zhou, J and Yang, Y}, title = {Long-term elevated CO2 shifts composition of soil microbial communities in a Californian annual grassland, reducing growth and N utilization potentials.}, journal = {The Science of the total environment}, volume = {652}, number = {}, pages = {1474-1481}, doi = {10.1016/j.scitotenv.2018.10.353}, pmid = {30586832}, issn = {1879-1026}, mesh = {California ; Carbon Dioxide/*analysis/toxicity ; Climate Change ; Desert Climate ; Environmental Monitoring/*methods ; *Grassland ; *Microbiota/genetics ; *Nitrogen Fixation/genetics ; Poaceae/*drug effects/growth &amp; development/metabolism ; Soil/chemistry ; *Soil Microbiology ; }, abstract = {The continuously increasing concentration of atmospheric CO2 has considerably altered ecosystem functioning. However, few studies have examined the long-term (i.e. over a decade) effect of elevated CO2 on soil microbial communities. Using 16S rRNA gene amplicons and a GeoChip microarray, we investigated soil microbial communities from a Californian annual grassland after 14 years of experimentally elevated CO2 (275 ppm higher than ambient). Both taxonomic and functional gene compositions of the soil microbial community were modified by elevated CO2. There was decrease in relative abundance for taxa with higher ribosomal RNA operon (rrn) copy number under elevated CO2, which is a functional trait that responds positively to resource availability in culture. In contrast, taxa with lower rrn copy number were increased by elevated CO2. As a consequence, the abundance-weighted average rrn copy number of significantly changed OTUs declined from 2.27 at ambient CO2 to 2.01 at elevated CO2. The nitrogen (N) fixation gene nifH and the ammonium-oxidizing gene amoA significantly decreased under elevated CO2 by 12.6% and 6.1%, respectively. Concomitantly, nitrifying enzyme activity decreased by 48.3% under elevated CO2, albeit this change was not significant. There was also a substantial but insignificant decrease in available soil N, with both nitrate (NO3-) (-27.4%) and ammonium (NH4+) (-15.4%) declining. Further, a large number of microbial genes related to carbon (C) degradation were also affected by elevated CO2, whereas those related to C fixation remained largely unchanged. The overall changes in microbial communities and soil N pools induced by long-term elevated CO2 suggest constrained microbial N decomposition, thereby slowing the potential maximum growth rate of the microbial community.}, }
@article {pmid30585386, year = {2019}, author = {Cholet, F and Ijaz, UZ and Smith, CJ}, title = {Differential ratio amplicons (Ramp) for the evaluation of RNA integrity extracted from complex environmental samples.}, journal = {Environmental microbiology}, volume = {21}, number = {2}, pages = {827-844}, doi = {10.1111/1462-2920.14516}, pmid = {30585386}, issn = {1462-2920}, support = {//Univeristy of Glasgow, School of Engineering Doctoral Scholarship/ ; NE/L011956/1//NERC IRF/ ; RCSRF1718643//Royal Academy of Engineering under the Research Chairs and Senior Research Fellowships scheme/ ; }, abstract = {Reliability and reproducibility of transcriptomics-based studies are dependent on RNA integrity. In microbial ecology, microfluidics-based techniques, such as the Ribosomal Integrity Number (RIN), targeting rRNA are currently the only approaches to evaluate RNA integrity. However, the relationship between rRNA and mRNA integrity is unknown. Here, we present an integrity index, the Ratio Amplicon, Ramp , adapted from human clinical studies, to directly monitor mRNA integrity from complex environmental samples. We show, in a suite of experimental degradations of RNA extracted from sediment, that while the RIN generally reflected the degradation status of RNA the Ramp mapped mRNA degradation better. Furthermore, we examined the effect of degradation on transcript community structure by amplicon sequencing of 16S rRNA, amoA and glnA transcripts. We successfully sequenced transcripts for all three targets even from highly-degraded RNA samples. While RNA degradation changed the community structure of the mRNA profiles, no changes were observed for the 16S rRNA transcript profiles. Since both RT-Q-PCR and sequencing results were obtained, even from highly degraded samples, we strongly recommend evaluating RNA integrity prior to downstream processing to ensure meaningful results. For this, both the RIN and Ramp are useful, with the Ramp better evaluating mRNA integrity in this study.}, }
@article {pmid30581429, year = {2018}, author = {Brenzinger, K and Drost, SM and Korthals, G and Bodelier, PLE}, title = {Organic Residue Amendments to Modulate Greenhouse Gas Emissions From Agricultural Soils.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3035}, doi = {10.3389/fmicb.2018.03035}, pmid = {30581429}, issn = {1664-302X}, abstract = {Organic fertilizers have been shown to stimulate CH4 uptake from agricultural soils. Managing fertilizer application to maximize this effect and to minimize emission of other greenhouse gasses offers possibilities to increase sustainability of agriculture. To tackle this challenge, we incubated an agricultural soil with different organic amendments (compost, sewage sludge, digestate, cover crop residues mixture), either as single application or in a mixture and subjected it to different soil moisture concentrations using different amounts of organic amendments. GHG fluxes and in vitro CH4 oxidation rates were measured repeatedly, while changes in organic matter and abundance of GHG relevant microbial groups (nitrifiers, denitrifiers, methanotrophs, methanogens) were measured at the end of the incubation. Overall the dynamics of the analyzed GHGs differed significantly. While CO2 and N2O differed considerably between the treatments, CH4 fluxes remained stable. In contrast, in vitro CH4 oxidation showed a clear increase for all amendments over time. CO2 fluxes were mostly dependent on the amount of organic residue that was used, while N2O fluxes were affected more by soil moisture. Several combinations of amendments led to reductions of CO2, CH4, and/or N2O emissions compared to un-amended soil. Most optimal GHG balance was obtained by compost amendments, which resulted in a similar overall GHG balance as compared to the un-amended soil. However, compost is not very nutrient rich potentially leading to lower crop yield when applied as single fertilizer. Hence, the combination of compost with one of the more nutrient rich organic amendments (sewage sludge, digestate) provides a trade-off between maintaining crop yield and minimizing GHG emissions. Additionally, we could observe a strong increase in microbial communities involved in GHG consumption in all amendments, with the strongest increase associated with cover crop residue mixtures. Future research should focus on the interrelation of plants, soil, and microbes and their impact on the global warming potential in relation to applied organic amendments.}, }
@article {pmid30580396, year = {2019}, author = {Williams, MR and Hashsham, SA}, title = {Direct or DNA Extraction-Free Amplification and Quantification of Foodborne Pathogens.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1918}, number = {}, pages = {21-33}, doi = {10.1007/978-1-4939-9000-9_2}, pmid = {30580396}, issn = {1940-6029}, abstract = {The use of direct nucleic acid amplification of pathogens from food matrices has the potential to reduce time to results over DNA extraction-based approaches as well as traditional culture-based approaches. Here we describe protocols for assay design and experiments for direct amplification of foodborne pathogens in food sample matrices using loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). The examples provided include the detection Escherichia coli in milk samples and Salmonella in pork meat samples. This protocol includes relevant reagents and methods including obtaining target sequences, assay design, sample processing, and amplification. These methods, though used for specific example matrices, could be applied to many other foodborne pathogens and sample types.}, }
@article {pmid30579209, year = {2019}, author = {Bains, W and Petkowski, JJ and Sousa-Silva, C and Seager, S}, title = {New environmental model for thermodynamic ecology of biological phosphine production.}, journal = {The Science of the total environment}, volume = {658}, number = {}, pages = {521-536}, doi = {10.1016/j.scitotenv.2018.12.086}, pmid = {30579209}, issn = {1879-1026}, mesh = {Bacteria/*metabolism ; *Environment ; Models, Chemical ; Oxidation-Reduction ; Phosphines/analysis/*metabolism ; Thermodynamics ; }, abstract = {We present a new model for the biological production of phosphine (PH3). Phosphine is found globally, in trace amounts, in the Earth's atmosphere. It has been suggested as a key molecule in the phosphorus cycle, linking atmospheric, lithospheric and biological phosphorus chemistry. Phosphine's production is strongly associated with marshes, swamps and other sites of anaerobic biology. However the mechanism of phosphine's biological production has remained controversial, because it has been believed that reduction of phosphate to phosphine is endergonic. In this paper we show through thermodynamic calculations that, in specific environments, the combined action of phosphate reducing and phosphite disproportionating bacteria can produce phosphine. Phosphate-reducing bacteria can capture energy from the reduction of phosphate to phosphite through coupling phosphate reduction to NADH oxidation. Our hypothesis describes how the phosphate chemistry in an environmental niche is coupled to phosphite generation in ground water, which in turn is coupled to the phosphine production in water and atmosphere, driven by a specific microbial ecology. Our hypothesis provides clear predictions on specific complex environments where biological phosphine production could be widespread. We propose tests of our hypothesis in fieldwork.}, }
@article {pmid30577137, year = {2019}, author = {Abreu-Junior, CH and de Lima Brossi, MJ and Monteiro, RT and Cardoso, PHS and da Silva Mandu, T and Nogueira, TAR and Ganga, A and Filzmoser, P and de Oliveira, FC and Firme, LP and He, Z and Capra, GF}, title = {Effects of sewage sludge application on unfertile tropical soils evaluated by multiple approaches: A field experiment in a commercial Eucalyptus plantation.}, journal = {The Science of the total environment}, volume = {655}, number = {}, pages = {1457-1467}, doi = {10.1016/j.scitotenv.2018.11.334}, pmid = {30577137}, issn = {1879-1026}, mesh = {Eucalyptus/*drug effects/growth &amp; development/physiology ; Fertilizers/*analysis ; Forestry ; Sewage/*adverse effects ; Soil/chemistry ; Soil Pollutants/*toxicity ; }, abstract = {Sewage sludge (SS) reuse in forest plantation as soil fertilizer/amendment has tremendously increased in recent years. However, SS may have high concentrations of potentially toxic elements (PTE), representing a potential risk for soil and the whole ecosystem. This paper was aimed to assess the toxicity of PTE in unfertile tropical soils amended with SS in a commercial Eucalyptus plantation, with an integrated multiple approaches combining: i) the use of a battery of bioassays (Daphnia magna, Pseudokcrichirella subcapitata, Lactuca sativa, and Allium cepa); and ii) the evaluation of some PTE (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and their availability into the pedoenvironment. Differences in total and available PTE between SS doses and time of treatments were evaluated using ANOVA; correlations between PTE and bioassays by a sparse partial robust M-regression (SPRM), while multiple correlations among parameters were performed by principal factor analysis (PFA). Results show that PTE contents in soils tended to increase with SS application doses. However this cannot be assumed as a general rule since in all the investigated treatments the PTE concentrations were consistently below both soil natural background concentrations and quality reference values. Bioassays showed a generalized low eco- and genotoxicity of SS with an increase in toxicity at increasing SS doses but with a clear decreasing trend as time went by. A. cepa was the most sensitive bioassay followed by P. subcapitata > D. magna > L. sativa. Overall, the results indicate that in realistic open field conditions SS risk may be lower than expected due to dynamic decrease in PTE toxicity with time after application. This study has an important implication that open-field trials should be strongly encouraged for evaluating environmental risk of SS application in forestry.}, }
@article {pmid30577127, year = {2019}, author = {Wang, D and Li, T and Huang, K and He, X and Zhang, XX}, title = {Roles and correlations of functional bacteria and genes in the start-up of simultaneous anammox and denitrification system for enhanced nitrogen removal.}, journal = {The Science of the total environment}, volume = {655}, number = {}, pages = {1355-1363}, doi = {10.1016/j.scitotenv.2018.11.321}, pmid = {30577127}, issn = {1879-1026}, mesh = {Ammonia/metabolism ; Bacteria/*metabolism ; *Bioreactors ; Denitrification ; Nitrogen/*metabolism ; RNA, Bacterial/analysis ; RNA, Ribosomal, 16S/analysis ; *Waste Disposal, Fluid ; }, abstract = {Simultaneous anammox and denitrification (SAD) is a newly developed wastewater treatment process efficient in nitrogen removal, but its underlying microbiological mechanisms during start-up remains unknown. This study investigated the changing patterns of functional bacteria and genes, as well as their correlation during the start-up (260 d) of the SAD systems in two lab-scale up-flow anaerobic sludge blanket bioreactors separately inoculated with anaerobic granular sludge (R1) and aerobic floccular sludge (R2). Results showed that high total nitrogen removal was achieved in the SAD systems of both R1 (88.25%) and R2 (89.42%). High-throughput sequencing of 16S rRNA gene amplicons revealed that Armatimonadetes phylum had a high abundance (44.34%) in R2, while was not detectable in R1 during the anammox stage. However, the SAD bioreactors retained inherent microbial community and the inoculation with different sludge showed less notable effects on their microbial composition. In the SAD systems, Candidatus Brocadia had high abundance in R1 (2.93%) and R2 (4.64%) and played important role in anammox. Network analysis indicated that Denitratisoma and Dokdonella were positively correlated with nitrite reductase genes nirS and nirK (p < 0.05), while Thermomonas and Pseudomonas showing a positive correlation with nitrate reductase gene narG (p < 0.05) were mainly responsible for the nitrate reduction in the SAD systems. Moreover, the overwhelming dominance of narG v.s. napA revealed the crucial roles of respiratory nitrate reduction in the bioreactors. The results extend our knowledge regarding the microbial ecology of the SAD system, which might be practically helpful for application of the process in wastewater treatment.}, }
@article {pmid30574135, year = {2018}, author = {Vander Roost, J and Daae, FL and Steen, IH and Thorseth, IH and Dahle, H}, title = {Distribution Patterns of Iron-Oxidizing Zeta- and Beta-Proteobacteria From Different Environmental Settings at the Jan Mayen Vent Fields.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3008}, doi = {10.3389/fmicb.2018.03008}, pmid = {30574135}, issn = {1664-302X}, abstract = {Iron oxidizers are widespread in marine environments and play an important role in marine iron cycling. However, little is known about the overall distribution of iron oxidizers within hydrothermal systems, including settings with little hydrothermal activity. Moreover, the extent to which different phylogenetic groups of iron oxidizers exhibit niche specialization toward different environmental settings, remains largely unknown. Obtaining such knowledge is critical to unraveling the impact of the activity of iron oxidizers and how they are adapted. Here, we used 16S rRNA sequencing to characterize the distribution of iron oxidizers in different environmental settings within the Jan Mayen hydrothermal vent fields (JMVFs). Putative iron oxidizers affiliated to Zetaproteobacteria and Betaproteobacteria were detected within iron mounds, bottom seawater, basalt surfaces, and surface layers of sediments. The detected iron oxidizers were compared to sequence types previously observed in patchily distributed iron mats associated with diffuse venting at the JMVFs. Most OTUs of iron oxidizers reoccurred under different environmental settings, suggesting a limited degree of niche specialization. Consequently, most of the detected iron oxidizers seem to be generalists with a large habitat range. Our study highlights the importance of gathering information about the overall distribution of iron oxidizers in hydrothermal systems to fully understand the role of this metabolic group regarding cycling of iron. Furthermore, our results provide further evidence of the presence of iron-oxidizing members of Betaproteobacteria in marine environments.}, }
@article {pmid30572962, year = {2018}, author = {Du Preez, S and Corbitt, M and Cabanas, H and Eaton, N and Staines, D and Marshall-Gradisnik, S}, title = {A systematic review of enteric dysbiosis in chronic fatigue syndrome/myalgic encephalomyelitis.}, journal = {Systematic reviews}, volume = {7}, number = {1}, pages = {241}, doi = {10.1186/s13643-018-0909-0}, pmid = {30572962}, issn = {2046-4053}, mesh = {Dietary Supplements ; *Dysbiosis ; Fatigue Syndrome, Chronic/*physiopathology ; *Gastrointestinal Microbiome ; Humans ; Probiotics ; Quality of Life/*psychology ; }, abstract = {BACKGROUND: Chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) is an illness characterised by profound and pervasive fatigue in addition to a heterogeneous constellation of symptoms. The aetiology of this condition remains unknown; however, it has been previously suggested that enteric dysbiosis is implicated in the pathogenesis of CFS/ME. This review examines the evidence currently available for the presence of abnormal microbial ecology in CFS/ME in comparison to healthy controls, with one exception being probiotic-supplemented CFS/ME patients, and whether the composition of the microbiome plays a role in symptom causation.<br><br>METHODS: EMBASE, Medline (via EBSCOhost), Pubmed and Scopus were systematically searched from 1994 to March 2018. All studies that investigated the gut microbiome composition of CFS/ME patients were initially included prior to the application of specific exclusion criteria. The association between these findings and patient-centred outcomes (fatigue, quality of life, gastrointestinal symptoms, psychological wellbeing) are also reported.<br><br>RESULTS: Seven studies that met the inclusion criteria were included in the review. The microbiome composition of CFS/ME patients was compared with healthy controls, with the exception of one study that compared to probiotic-supplemented CFS/ME patients. Differences were reported in each study; however, only three were considered statistically significant, and the findings across all studies were inconsistent. The quality of the studies included in this review scored between poor (< 54%), fair (54-72%) and good (94-100%) using the Downs and Black checklist.<br><br>CONCLUSIONS: There is currently insufficient evidence for enteric dysbiosis playing a significant role in the pathomechanism of CFS/ME. Recommendations for future research in this field include the use of consistent criteria for the diagnosis of CFS/ME, reduction of confounding variables by controlling factors that influence microbiome composition prior to sample collection and including more severe cases of CFS/ME.}, }
@article {pmid30568671, year = {2018}, author = {Bardin, M and Leyronas, C and Troulet, C and Morris, CE}, title = {Striking Similarities Between Botrytis cinerea From Non-agricultural and From Agricultural Habitats.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {1820}, doi = {10.3389/fpls.2018.01820}, pmid = {30568671}, issn = {1664-462X}, abstract = {Investigations into life history of microorganisms that cause plant diseases have been limited mostly to contexts where they are in interaction with plants, and with cropped or otherwise managed vegetation. Therefore, knowledge about the diversity of plant pathogens, about potential reservoirs of inoculum and about the processes that contribute to their survival and adaptation is limited to these contexts. The agro-centric perspective of plant pathogen life histories is incoherent with respect to the capacity of many of them to persist as saprophytes on various substrates. In this context we have investigated the ubiquity of the broad host range necrotrophic fungus Botrytis cinerea, outside of agricultural settings and have determined if the populations in these natural habitats can be distinguished phenotypically and phylogenetically from populations isolated from diseased crops. Over a period of 5 years, we isolated B. cinerea from 235 samples of various substrates collected in France including rainfall, snowpack, river, and lake water, epilithic biofilms in mountain streams, leaf litter and plant debris, rock surfaces, bird feathers and healthy wild plants from outside of agricultural fields. All substrates except rock surfaces harbored B. cinerea leading us to establish a collection of purified strains that were compared to B. cinerea from diseased tomato, grapes and various other crops in France. Phylogenetic comparisons of 321 strains from crop plants and 100 strains from environmental substrates based on sequences of 9 microsatellite markers revealed that strains from crops and the environment could not be distinguished. Furthermore, the genetic diversity of strains outside of agriculture was just as broad as within agriculture. In tests to determine the aggressiveness of strains on tomato stems, the mean disease severity caused by strains from environmental substrates was statistically identical to the severity of disease caused by strains from tomato, but was significantly greater than the severity caused by strains from grape or other crops. Our results suggest that highly diverse populations of this plant pathogen persist outside of agriculture in association with substrates other than plants and that this part of their life history is compatible with its capacity to maintain its potential as plant pathogen.}, }
@article {pmid30565880, year = {2019}, author = {Thorn, CE and Bergesch, C and Joyce, A and Sambrano, G and McDonnell, K and Brennan, F and Heyer, R and Benndorf, D and Abram, F}, title = {A robust, cost-effective method for DNA, RNA and protein co-extraction from soil, other complex microbiomes and pure cultures.}, journal = {Molecular ecology resources}, volume = {19}, number = {2}, pages = {439-455}, doi = {10.1111/1755-0998.12979}, pmid = {30565880}, issn = {1755-0998}, support = {//NUI Galway/ ; }, mesh = {Cost-Benefit Analysis ; DNA/genetics/*isolation &amp; purification ; Metagenomics/economics/*methods ; *Microbiota ; Proteins/analysis/*isolation &amp; purification ; Proteomics/economics/*methods ; RNA/genetics/*isolation &amp; purification ; *Soil Microbiology ; }, abstract = {The soil microbiome is inherently complex with high biological diversity, and spatial heterogeneity typically occurring on the submillimetre scale. To study the microbial ecology of soils, and other microbiomes, biomolecules, that is, nucleic acids and proteins, must be efficiently and reliably co-recovered from the same biological samples. Commercial kits are currently available for the co-extraction of DNA, RNA and proteins but none has been developed for soil samples. We present a new protocol drawing on existing phenol-chloroform-based methods for nucleic acids co-extraction but incorporating targeted precipitation of proteins from the phenol phase. The protocol is cost-effective and robust, and easily implemented using reagents commonly available in laboratories. The method is estimated to be eight times cheaper than using disparate commercial kits for the isolation of DNA and/or RNA, and proteins, from soil. The method is effective, providing good quality biomolecules from a diverse range of soil types, with clay contents varying from 9.5% to 35.1%, which we successfully used for downstream, high-throughput gene sequencing and metaproteomics. Additionally, we demonstrate that the protocol can also be easily implemented for biomolecule co-extraction from other complex microbiome samples, including cattle slurry and microbial communities recovered from anaerobic bioreactors, as well as from Gram-positive and Gram-negative pure cultures.}, }
@article {pmid30565684, year = {2019}, author = {Wang, JC and Bergeron, M and Andersen, H and Tikhtman, R and Haslam, D and Hunter, T and Herr, AB and de Alarcon, A}, title = {Feasibility of shotgun metagenomics to assess microbial ecology of pediatric tracheostomy tubes.}, journal = {The Laryngoscope}, volume = {129}, number = {2}, pages = {317-323}, doi = {10.1002/lary.27356}, pmid = {30565684}, issn = {1531-4995}, mesh = {Biofilms/*growth &amp; development ; Child ; Child, Preschool ; Equipment Contamination ; Feasibility Studies ; Female ; Humans ; Infant ; Male ; Metagenomics/*methods ; Tracheostomy/*instrumentation ; }, abstract = {OBJECTIVE: Biofilm formation on medical devices such as tracheostomy tubes (TTs) is a serious problem. The clinical impact of biofilms on the airway is still unclear. Biofilms may play a role in granulation tissue development, recurrent airway infections, and failure of laryngotracheal reconstructions. The microbial ecology on TTs has yet to be elucidated. The purpose of this study was to determine the feasibility of shotgun metagenomics to assess the biodistribution of microorganisms on TTs.<br><br>METHODS: Four TTs were collected from pediatric patients (1.4-10.2 years) with (n = 2) and without (n = 2) granulation tissue formation. Duration of TT placement prior to retrieval from patients ranged from 5 to 365 days. DNA extraction was performed using the MO BIO UltraClean Microbial Isolation (Mo Bio Laboratories, Carlsbad, CA). Library generation using Nextera XT adapters (Illumina Inc., San Diego, CA) and metagenomic shotgun sequencing was performed using the Illumina NextSeq500 (Illumina Inc, San Diego, CA). Salinibacter ruber, a species not found in mammalian microbiome communities, was used as a DNA standard and represented 0.7% to 5.7% of the microbiome, ensuring good quality and abundance of sample DNA.<br><br>RESULTS: Metagenomic shotgun sequencing was successful for all patients. In TTs associated with granuloma, Fusobacterium nucleatum, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae were predominant, most of which are considered pathogens. From TTs without granulomas, Neisseria mucosa, Neisseria sicca, Acinetobacter baumannii, and Haemophilus parainfluenzae were identified, primarily consistent with respiratory microbiome.<br><br>CONCLUSION: This study reveals that metagenomic shotgun sequencing of biofilms formed on pediatric TTs is feasible with an apparent difference in microbiome for patients with granulation tissue. Further studies are necessary to elucidate the pathogenesis of microbial ecology and its role in airway disease in patients with TTs.<br><br>LEVEL OF EVIDENCE: 2c Laryngoscope, 129:317-323, 2019.}, }
@article {pmid30565024, year = {2019}, author = {Lee, JC and Song, JS and Whang, KS}, title = {Sphingobium pinisoli sp. nov., isolated from the rhizosphere soil of a Korean native pine tree.}, journal = {Antonie van Leeuwenhoek}, volume = {112}, number = {6}, pages = {815-825}, doi = {10.1007/s10482-018-01215-x}, pmid = {30565024}, issn = {1572-9699}, support = {PJ01287601//Department of Agriculture and Rural Development/ ; }, abstract = {A Gram-stain negative, aromatic compound degrading bacterium, designated strain ASA28T, was isolated from the rhizosphere soil of a pine tree at Anmyon island, Taean in Korea. Strain ASA28T was found to be strictly aerobic, non-motile, short rods which can grow at 15-28 °C (optimum, 25-28 °C), at pH 5.0-11.0 (optimum, pH 7.0) and at salinities of 0-1.0% (w/v) NaCl (optimum, 0% NaCl). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain ASA28T belongs to the genus Sphingobium, showing high sequence similarity to Sphingobium scionense WP01T (97.8%), Sphingobium vermicocomposti VC-230T (96.8%), Sphingobium yanoikuyae ATCC 51230T (96.5%) and Sphingobium herbicidovorans MHT (95.6%). The predominant ubiquinone and polyamine components were identified as Q-10 and spermidine, respectively. The major fatty acids were identified as C18:1ω7c, C16:0, C14:0 2-OH and C16:1ω7c and/or C15:0 iso 2-OH. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, sphingoglycolipid, phosphoglycolipid, four unidentified aminophospholipids, an unidentified aminolipid, two unidentified phospholipids and six unidentified lipids. The DNA G+C content of this novel isolate was determined to be 63.0 mol%. DNA-DNA relatedness between strain ASA28T and S. herbicidovorans KCTC 2939T, S. vermicocomposti DSM 21299T and S. scionense DSM 19371T was determined to be 32 ± 5%, 30 ± 4% and 25 ± 5%, respectively. On the basis of the phylogenetic, phenotypic and chemotaxonomic analyses in this study, strain ASA28T is considered to represent a novel species of the genus Sphingobium, for which the name Sphingobium pinisoli sp. nov. is proposed. The type strain is ASA28T (= KACC 18700T = NBRC 112246T).}, }
@article {pmid30564217, year = {2018}, author = {Ramírez, GA and Jørgensen, SL and Zhao, R and D'Hondt, S}, title = {Minimal Influence of Extracellular DNA on Molecular Surveys of Marine Sedimentary Communities.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2969}, doi = {10.3389/fmicb.2018.02969}, pmid = {30564217}, issn = {1664-302X}, abstract = {Extracellular DNA has been reported to comprise a large fraction of total DNA in near-seafloor sediment. However, the potential effect of extracellular DNA, arising from dead or moribund cells, on sequencing surveys is a critical concern that has largely not been addressed for marine sedimentary habitats. To address this concern, we interrogated freshly collected Arctic and Pacific sediment for extracellular 16S rRNA genes using the photoactive DNA-binding dye Propidium Monoazide. Significant differences between relative abundances of total (intracellular + extracellular) Bacterial 16S rRNA genes and relative abundances of intracellular Bacterial 16S rRNA genes are only detected in three of twelve shallow [10 cm below seafloor (cmbsf)] samples. Relative abundances of total Bacterial 16S rRNA genes are statistically indistinguishable from relative abundances of intracellular Bacterial 16S rRNA genes in all interrogated samples from depths greater than 10 cmbsf. 16S rRNA gene sequencing shows that even where significantly higher abundances of extracellular genes are detected, they have little or no influence on prokaryote community composition. Taxon-level analyses suggest that extracellular DNA, arising from in situ death, may be sourced from different organisms in sediment of different ages. However, the overall effect of extracellular genes on sequencing surveys of marine sedimentary prokaryotes is minimal.}, }
@article {pmid30564202, year = {2018}, author = {Too, CC and Keller, A and Sickel, W and Lee, SM and Yule, CM}, title = {Microbial Community Structure in a Malaysian Tropical Peat Swamp Forest: The Influence of Tree Species and Depth.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2859}, doi = {10.3389/fmicb.2018.02859}, pmid = {30564202}, issn = {1664-302X}, abstract = {Tropical peat swamp forests sequester globally significant stores of carbon in deep layers of waterlogged, anoxic, acidic and nutrient-depleted peat. The roles of microbes in supporting these forests through the formation of peat, carbon sequestration and nutrient cycling are virtually unknown. This study investigated physicochemical peat properties and microbial diversity between three dominant tree species: Shorea uliginosa (Dipterocarpaceae), Koompassia malaccensis (legumes associated with nitrogen-fixing bacteria), Eleiodoxa conferta (palm) and depths (surface, 45 and 90 cm) using microbial 16S rRNA gene amplicon sequencing. Water pH, oxygen, nitrogen, phosphorus, total phenolic contents and C/N ratio differed significantly between depths, but not tree species. Depth also strongly influenced microbial diversity and composition, while both depth and tree species exhibited significant impact on the archaeal communities. Microbial diversity was highest at the surface, where fresh leaf litter accumulates, and nutrient supply is guaranteed. Nitrogen was the core parameter correlating to microbial communities, but the interactive effects from various environmental variables displayed significant correlation to relative abundance of major microbial groups. Proteobacteria was the dominant phylum and the most abundant genus, Rhodoplanes, might be involved in nitrogen fixation. The most abundant methanogens and methanotrophs affiliated, respectively, to families Methanomassiliicoccaceae and Methylocystaceae. Our results demonstrated diverse microbial communities and provide valuable insights on microbial ecology in these extreme ecosystems.}, }
@article {pmid30562060, year = {2019}, author = {Arora, T and Rudenko, O and Egerod, KL and Husted, AS and Kovatcheva-Datchary, P and Akrami, R and Kristensen, M and Schwartz, TW and Bäckhed, F}, title = {Microbial fermentation of flaxseed fibers modulates the transcriptome of GPR41-expressing enteroendocrine cells and protects mice against diet-induced obesity.}, journal = {American journal of physiology. Endocrinology and metabolism}, volume = {316}, number = {3}, pages = {E453-E463}, doi = {10.1152/ajpendo.00391.2018}, pmid = {30562060}, issn = {1522-1555}, abstract = {Dietary fibers, an integral part of the human diet, require the enzymatic activity of the gut microbiota for complete metabolism into short-chain fatty acids (SCFAs). SCFAs are important modulators of host metabolism and physiology and act in part as signaling molecules by activating G protein-coupled receptors (GPCRs), such as GPR41. Flaxseed fibers improve metabolism in rodents and mice, but their fermentation profiles, effects on enteroendocrine cells, and associated metabolic benefits are unknown. We fed GPR41-red fluorescent protein mice, an enteroendocrine reporter mouse strain, chow, high-fat diet (HFD), or HFD supplemented either with 10% nonfermentable fiber cellulose or fermentable flaxseed fibers for 12 wk to assess changes in cecal gut microbiota, enteroendocrine cell transcriptome in the ileum and colon, and physiological parameters. We observed that flaxseed fibers restructured the gut microbiota and promoted proliferation of the genera Bifidobacterium and Akkermansia compared with HFD. The shifts in cecal bacterial composition restored levels of the SCFAs butyrate similar to the chow diet, resulting in colonic but not ileal enteroendocrine cell transcriptional changes in genes related to cell cycle, mRNA, and protein transport compared with HFD. Consistent with the effects on enteroendocrine functions, flaxseed fibers also protected mice from diet-induced obesity, potentially by preventing a reduction in energy expenditure induced by an HFD. Our study shows that flaxseed fibers alter cecal microbial ecology, are fermented to SCFAs in the cecum, and modulate enteroendocrine cell transcriptome in the colon, which may contribute to their metabolically favorable phenotype.}, }
@article {pmid30559748, year = {2018}, author = {Guyonnet, JP and Guillemet, M and Dubost, A and Simon, L and Ortet, P and Barakat, M and Heulin, T and Achouak, W and Haichar, FEZ}, title = {Plant Nutrient Resource Use Strategies Shape Active Rhizosphere Microbiota Through Root Exudation.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {1662}, doi = {10.3389/fpls.2018.01662}, pmid = {30559748}, issn = {1664-462X}, abstract = {Plant strategies for soil nutrient uptake have the potential to strongly influence plant-microbiota interactions, due to the competition between plants and microorganisms for soil nutrient acquisition and/or conservation. In the present study, we investigate whether these plant strategies could influence rhizosphere microbial activities via root exudation, and contribute to the microbiota diversification of active bacterial communities colonizing the root-adhering soil (RAS) and inhabiting the root tissues. We applied a DNA-based stable isotope probing (DNA-SIP) approach to six grass species distributed along a gradient of plant nutrient resource strategies, from conservative species, characterized by low nitrogen (N) uptake, a long lifespans and low root exudation level, to exploitative species, characterized by high rates of photosynthesis, rapid rates of N uptake and high root exudation level. We analyzed their (i) associated microbiota composition involved in root exudate assimilation and soil organic matter (SOM) degradation by 16S-rRNA-based metabarcoding. (ii) We determine the impact of root exudation level on microbial activities (denitrification and respiration) by gas chromatography. Measurement of microbial activities revealed an increase in denitrification and respiration activities for microbial communities colonizing the RAS of exploitative species. This increase of microbial activities results probably from a higher exudation rate and more diverse metabolites by exploitative plant species. Furthermore, our results demonstrate that plant nutrient resource strategies have a role in shaping active microbiota. We present evidence demonstrating that plant nutrient use strategies shape active microbiota involved in root exudate assimilation and SOM degradation via root exudation.}, }
@article {pmid30555445, year = {2018}, author = {Ilgrande, C and Leroy, B and Wattiez, R and Vlaeminck, SE and Boon, N and Clauwaert, P}, title = {Metabolic and Proteomic Responses to Salinity in Synthetic Nitrifying Communities of Nitrosomonas spp. and Nitrobacter spp.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2914}, doi = {10.3389/fmicb.2018.02914}, pmid = {30555445}, issn = {1664-302X}, abstract = {Typically, nitrification is a two-stage microbial process and is key in wastewater treatment and nutrient recovery from waste streams. Changes in salinity represent a major stress factor that can trigger response mechanisms, impacting the activity and the physiology of bacteria. Despite its pivotal biotechnological role, little information is available on the specific response of nitrifying bacteria to varying levels of salinity. In this study, synthetic communities of ammonia-oxidizing bacteria (AOB Nitrosomonas europaea and/or Nitrosomonas ureae) and nitrite-oxidizing bacteria (NOB Nitrobacter winogradskyi and/or Nitrobacter vulgaris) were tested at 5, 10, and 30 mS cm-1 by adding sodium chloride to the mineral medium (0, 40, and 200 mM NaCl, respectively). Ammonia oxidation activity was less affected by salinity than nitrite oxidation. AOB, on their own or in combination with NOB, showed no significant difference in the ammonia oxidation rate among the three conditions. However, N. winogradskyi improved the absolute ammonia oxidation rate of both N. europaea and N. ureae. N. winogradskyi's nitrite oxidation rate decreased to 42% residual activity upon exposure to 30 mS cm-1, also showing a similar behavior when tested with Nitrosomonas spp. The nitrite oxidation rate of N. vulgaris, as a single species, was not affected when adding sodium chloride up to 30 mS cm-1, however, its activity was completely inhibited when combined with Nitrosomonas spp. in the presence of ammonium/ammonia. The proteomic analysis of a co-culture of N. europaea and N. winogradskyi revealed the production of osmolytes, regulation of cell permeability and an oxidative stress response in N. europaea and an oxidative stress response in N. winogradskyi, as a result of increasing the salt concentration from 5 to 30 mS cm-1. A specific metabolic response observed in N. europaea suggests the role of carbon metabolism in the production of reducing power, possibly to meet the energy demands of the stress response mechanisms, induced by high salinity. For the first time, metabolic modifications and response mechanisms caused by the exposure to salinity were described, serving as a tool toward controllability and predictability of nitrifying systems exposed to salt fluctuations.}, }
@article {pmid30555443, year = {2018}, author = {Tanaka, K and Yokoe, S and Igarashi, K and Takashino, M and Ishikawa, M and Hori, K and Nakanishi, S and Kato, S}, title = {Extracellular Electron Transfer via Outer Membrane Cytochromes in a Methanotrophic Bacterium Methylococcus capsulatus (Bath).}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2905}, doi = {10.3389/fmicb.2018.02905}, pmid = {30555443}, issn = {1664-302X}, abstract = {Electron exchange reactions between microbial cells and solid materials, referred to as extracellular electron transfer (EET), have attracted attention in the fields of microbial physiology, microbial ecology, and biotechnology. Studies of model species of iron-reducing, or equivalently, current-generating bacteria such as Geobacter spp. and Shewanella spp. have revealed that redox-active proteins, especially outer membrane c-type cytochromes (OMCs), play a pivotal role in the EET process. Recent (meta)genomic analyses have revealed that diverse microorganisms that have not been demonstrated to have EET ability also harbor OMC-like proteins, indicating that EET via OMCs could be more widely preserved in microorganisms than originally thought. A methanotrophic bacterium Methylococcus capsulatus (Bath) was reported to harbor multiple OMC genes whose expression is elevated by Cu starvation. However, the physiological role of these genes is unknown. Therefore, in this study, we explored whether M. capsulatus (Bath) displays EET abilities via OMCs. In electrochemical analysis, M. capsulatus (Bath) generated anodic current only when electron donors such as formate were available, and could reduce insoluble iron oxides in the presence of electron donor compounds. Furthermore, the current-generating and iron-reducing activities of M. capsulatus (Bath) cells that were cultured in a Cu-deficient medium, which promotes high levels of OMC expression, were higher than those cultured in a Cu-supplemented medium. Anodic current production by the Cu-deficient cells was significantly suppressed by disruption of MCA0421, a highly expressed OMC gene, and by treatment with carbon monoxide (CO) gas (an inhibitor of c-type cytochromes). Our results provide evidence of EET in M. capsulatus (Bath) and demonstrate the pivotal role of OMCs in this process. This study raises the possibility that EET to solid compounds is a novel survival strategy of methanotrophic bacteria.}, }
@article {pmid30554808, year = {2019}, author = {Sutherland, WJ and Broad, S and Butchart, SHM and Clarke, SJ and Collins, AM and Dicks, LV and Doran, H and Esmail, N and Fleishman, E and Frost, N and Gaston, KJ and Gibbons, DW and Hughes, AC and Jiang, Z and Kelman, R and LeAnstey, B and le Roux, X and Lickorish, FA and Monk, KA and Mortimer, D and Pearce-Higgins, JW and Peck, LS and Pettorelli, N and Pretty, J and Seymour, CL and Spalding, MD and Wentworth, J and Ockendon, N}, title = {A Horizon Scan of Emerging Issues for Global Conservation in 2019.}, journal = {Trends in ecology &amp; evolution}, volume = {34}, number = {1}, pages = {83-94}, doi = {10.1016/j.tree.2018.11.001}, pmid = {30554808}, issn = {1872-8383}, mesh = {Biodiversity ; *Conservation of Natural Resources/trends ; *Forecasting ; }, abstract = {We present the results of our tenth annual horizon scan. We identified 15 emerging priority topics that may have major positive or negative effects on the future conservation of global biodiversity, but currently have low awareness within the conservation community. We hope to increase research and policy attention on these areas, improving the capacity of the community to mitigate impacts of potentially negative issues, and maximise the benefits of issues that provide opportunities. Topics include advances in crop breeding, which may affect insects and land use; manipulations of natural water flows and weather systems on the Tibetan Plateau; release of carbon and mercury from melting polar ice and thawing permafrost; new funding schemes and regulations; and land-use changes across Indo-Malaysia.}, }
@article {pmid30554770, year = {2019}, author = {Cordier, T and Lanzén, A and Apothéloz-Perret-Gentil, L and Stoeck, T and Pawlowski, J}, title = {Embracing Environmental Genomics and Machine Learning for Routine Biomonitoring.}, journal = {Trends in microbiology}, volume = {27}, number = {5}, pages = {387-397}, doi = {10.1016/j.tim.2018.10.012}, pmid = {30554770}, issn = {1878-4380}, abstract = {Genomics is fast becoming a routine tool in medical diagnostics and cutting-edge biotechnologies. Yet, its use for environmental biomonitoring is still considered a futuristic ideal. Until now, environmental genomics was mainly used as a replacement of the burdensome morphological identification, to screen known morphologically distinguishable bioindicator taxa. While prokaryotic and eukaryotic microbial diversity is of key importance in ecosystem functioning, its implementation in biomonitoring programs is still largely unappreciated, mainly because of difficulties in identifying microbes and limited knowledge of their ecological functions. Here, we argue that the combination of massive environmental genomics microbial data with machine learning algorithms can be extremely powerful for biomonitoring programs and pave the way to fill important gaps in our understanding of microbial ecology.}, }
@article {pmid30554323, year = {2019}, author = {Jiang, N and Liu, H and Wang, P and Huang, J and Han, H and Wang, Q}, title = {Illumina MiSeq Sequencing Investigation of Microbiota in Bronchoalveolar Lavage Fluid and Cecum of the Swine Infected with PRRSV.}, journal = {Current microbiology}, volume = {76}, number = {2}, pages = {222-230}, doi = {10.1007/s00284-018-1613-y}, pmid = {30554323}, issn = {1432-0991}, support = {No. 81172777//the National Natural Science Foundation of China under Grant/ ; No. 2014B11NC096//the Dalian Science and Technological Project under Grant/ ; }, mesh = {Animals ; Antibodies, Viral/blood ; Bacteria/genetics/*isolation &amp; purification/pathogenicity ; Bronchoalveolar Lavage Fluid/*microbiology ; Cecum/*microbiology ; Coinfection/microbiology/*veterinary/virology ; Dysbiosis/microbiology ; Feces/microbiology ; High-Throughput Nucleotide Sequencing ; Lung/microbiology ; Microbiota ; Mucous Membrane/microbiology ; Porcine Reproductive and Respiratory Syndrome/*microbiology ; Porcine respiratory and reproductive syndrome virus/genetics ; Swine ; }, abstract = {Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant animal morbidity and mortality and economic losses worldwide. In this study, we analyzed the microbiota in bronchoalveolar lavage fluid (BAL), mucosa, and feces in cecum of the PRRSV-challenged pigs using the Illumina MiSeq sequencing platform, to investigate the role of microbiota in the pathogenesis and development of porcine reproductive and respiratory syndrome (PRRS). Quantitative insights into microbial ecology analyses indicated that the dominant bacterial groups in the lung from the PRRSV-challenged pigs were Haemophilus parasuis and Mycoplasma hyorhinis, with a relative abundance of 35-48% and 27-41%, respectively. Our results were consistent with the clinical observation that the PRRSV-infected pigs are always co-infected with other bacteria, such as Haemophilus and Mycoplasma. On the other hand, Campylobacter and Clostridium became the two most abundant bacteria in the mucosal and luminal microbiota of the cecum of the PRRSV-challenged pigs, and the relative abundance was four times higher than that in the healthy pigs. This suggested that Campylobacter and Clostridium might be associated with the pathogenesis of diarrhea in PRRS. Linear discriminant analysis effect size reveals significant microbial dysbiosis of BAL, mucosa, and feces in cecum of the PRRSV-challenged pigs. We have identified a structural imbalance of the microbiota, characterized by a reduced diversity of microbiota and abundance alterations of certain bacteria in the PRRSV-challenged pigs. The observed microbiota dysbiosis in this study provides insight into the roles of the microbiota in the complications of the PRRSV infection.}, }
@article {pmid30552443, year = {2018}, author = {Rothman, JA and Andrikopoulos, C and Cox-Foster, D and McFrederick, QS}, title = {Floral and Foliar Source Affect the Bee Nest Microbial Community.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1300-3}, pmid = {30552443}, issn = {1432-184X}, support = {NNX15AP99A//National Aeronautics and Space Administration/ ; 2018-67011-28123//National Institute of Food and Agriculture/ ; CA-R-ENT-5109-H//National Institute of Food and Agriculture/ ; }, abstract = {Managed pollinators such as the alfalfa leafcutting bee, Megachile rotundata, are essential to the production of a wide variety of agricultural crops. These pollinators encounter a diverse array of microbes when foraging for food and nest-building materials on various plants. To test the hypothesis that food and nest-building source affects the composition of the bee-nest microbiome, we exposed M. rotundata adults to treatments that varied both floral and foliar source in a 2 × 2 factorial design. We used 16S rRNA gene and internal transcribed spacer (ITS) sequencing to capture the bacterial and fungal diversity of the bee nests. We found that nest microbial communities were significantly different between treatments, indicating that bee nests become inoculated with environmentally derived microbes. We did not find evidence of interactions between the fungi and bacteria within our samples. Furthermore, both the bacterial and fungal communities were quite diverse and contained numerous exact sequence variants (ESVs) of known plant and bee pathogens that differed based on treatment. Our research indicates that bees deposit plant-associated microbes into their nests, including multiple plant pathogens such as smut fungi and bacteria that cause blight and wilt. The presence of plant pathogens in larval pollen provisions highlights the potential for bee nests to act as disease reservoirs across seasons. We therefore suggest that future research should investigate the ability of bees to transmit pathogens from nest to host plant.}, }
@article {pmid30547761, year = {2018}, author = {Morales-Cruz, A and Figueroa-Balderas, R and García, JF and Tran, E and Rolshausen, PE and Baumgartner, K and Cantu, D}, title = {Profiling grapevine trunk pathogens in planta: a case for community-targeted DNA metabarcoding.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {214}, doi = {10.1186/s12866-018-1343-0}, pmid = {30547761}, issn = {1471-2180}, abstract = {BACKGROUND: DNA metabarcoding, commonly used in exploratory microbial ecology studies, is a promising method for the simultaneous in planta-detection of multiple pathogens associated with disease complexes, such as the grapevine trunk diseases. Profiling of pathogen communities associated with grapevine trunk diseases is particularly challenging, due to the presence within an individual wood lesion of multiple co-infecting trunk pathogens and other wood-colonizing fungi, which span a broad range of taxa in the fungal kingdom. As such, we designed metabarcoding primers, using as template the ribosomal internal transcribed spacer of grapevine trunk-associated ascomycete fungi (GTAA) and compared them to two universal primer widely used in microbial ecology.<br><br>RESULTS: We first performed in silico simulations and then tested the primers by high-throughput amplicon sequencing of (i) multiple combinations of mock communities, (ii) time-course experiments with controlled inoculations, and (iii) diseased field samples from vineyards under natural levels of infection. All analyses showed that GTAA had greater affinity and sensitivity, compared to those of the universal primers. Importantly, with GTAA, profiling of mock communities and comparisons with shotgun-sequencing metagenomics of field samples gave an accurate representation of genera of important trunk pathogens, namely Phaeomoniella, Phaeoacremonium, and Eutypa, the abundances of which were over- or under-estimated with universal primers.<br><br>CONCLUSIONS: Overall, our findings not only demonstrate that DNA metabarcoding gives qualitatively and quantitatively accurate results when applied to grapevine trunk diseases, but also that primer customization and testing are crucial to ensure the validity of DNA metabarcoding results.}, }
@article {pmid30547194, year = {2018}, author = {Visvalingam, J and Zhang, P and Ells, TC and Yang, X}, title = {Dynamics of Biofilm Formation by Salmonella Typhimurium and Beef Processing Plant Bacteria in Mono- and Dual-Species Cultures.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1304-z}, pmid = {30547194}, issn = {1432-184X}, support = {A-1603 and A-1637//Agriculture and Agri-Food Canada/ ; }, abstract = {This study aimed to determine the impact of bacteria from a beef plant conveyor belt on the biofilm formation of Salmonella in dual-species cultures. Beef plant isolates (50) including 18 Gram-negative aerobes (GNA), 8 Gram-positive aerobes (GPA), 5 lactic acid bacteria (LAB), 9 Enterobacteriaceae (EB), and 10 generic Escherichia coli (GEC) were included for developing biofilms in mono- and co-culture with S. Typhimurium at 15 °C for 6 days. Five selected cultures in planktonic form and in biofilms were tested for susceptibility to two commonly used sanitizers (i.e. E-San and Perox-E Plus). In mono-cultures, ≥ 80, 67, 61, 20, and 13% of GEC, EB, GNA, LAB, and GPA, respectively, developed measurable biofilms after 2 days, while all co-culture pairings with S. Typhimurium achieved some level of biofilm production. The predominant effect of EB and only effect of GEC strains on the biofilm formation of S. Typhimurium was antagonistic, while that of Gram-positive bacteria was synergistic, with the effect being more prominent on day 6. The effect was highly variable for the GNA isolates. Six aerobic isolates that formed moderate/strong biofilms by day 2 greatly boosted the co-culture biofilm formation. Seven Gram-negative bacteria were antagonistic against the biofilm formation of the co-cultures. Both sanitizers completely inactivated the selected planktonic cultures, but were largely ineffective against biofilms. In conclusion, all beef plant isolates assessed formed biofilms when paired with S. Typhimurium. Aerobic biofilm formers may create a more favorable condition for Salmonella biofilm formation, while some beef plant isolates have potential as a biocontrol strategy for Salmonella biofilms.}, }
@article {pmid30545051, year = {2018}, author = {Haro, C and Villatoro, M and Vaquero, L and Pastor, J and Giménez, MJ and Ozuna, CV and Sánchez-León, S and García-Molina, MD and Segura, V and Comino, I and Sousa, C and Vivas, S and Landa, BB and Barro, F}, title = {The Dietary Intervention of Transgenic Low-Gliadin Wheat Bread in Patients with Non-Celiac Gluten Sensitivity (NCGS) Showed No Differences with Gluten Free Diet (GFD) but Provides Better Gut Microbiota Profile.}, journal = {Nutrients}, volume = {10}, number = {12}, pages = {}, doi = {10.3390/nu10121964}, pmid = {30545051}, issn = {2072-6643}, support = {Projects AGL2013-48946-C3-1-R, AGL2013-48946-C and AGL2016-80566-P//Ministerio de Economía, Industria y Competitividad, Gobierno de España/ ; }, mesh = {Adult ; Diet, Gluten-Free/*statistics &amp; numerical data ; Feces/chemistry/microbiology ; Female ; Gastrointestinal Microbiome/*physiology ; Gliadin/*adverse effects/*analysis ; High-Throughput Nucleotide Sequencing ; Humans ; Malabsorption Syndromes/*diet therapy ; Male ; Middle Aged ; Plants, Genetically Modified/genetics ; Triticum/genetics ; }, abstract = {The study evaluated the symptoms, acceptance, and digestibility of bread made from transgenic low-gliadin wheat, in comparison with gluten free bread, in Non-coeliac gluten sensitivity (NCGS) patients, considering clinical/sensory parameters and gut microbiota composition. This study was performed in two phases of seven days each, comprising a basal phase with gluten free bread and an E82 phase with low-gliadin bread. Gastrointestinal clinical symptoms were evaluated using the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire, and stool samples were collected for gluten immunogenic peptides (GIP) determination and the extraction of gut microbial DNA. For the basal and E82 phases, seven and five patients, respectively, showed undetectable GIPs content. The bacterial 16S rRNA gene V1-V2 hypervariable regions were sequenced using the Illumina MiSeq platform and downstream analysis was done using a Quantitative Insights into Microbial Ecology (QIIME) pipeline. No significant differences in the GSRS questionnaires were observed between the two phases. However, we observed a significantly lower abundance of some gut genera Oscillospira, Dorea, Blautia, Bacteroides, Coprococcus, and Collinsella, and a significantly higher abundance of Roseburia and Faecalibacterium genera during the E82 phase compared with the basal phase. The consumption of low-gliadin bread E82 by NCGS subjects induced potentially positive changes in the gut microbiota composition, increasing the butyrate-producing bacteria and favoring a microbial profile that is suggested to have a key role in the maintenance or improvement of gut permeability.}, }
@article {pmid30544668, year = {2018}, author = {Kaboré, WAD and Dembélé, R and Bagré, TS and Konaté, A and Boisramé, S and Chevalier, V and Konsem, T and Traoré, AS and Barro, N}, title = {Characterization and Antimicrobial Susceptibility of Lactococcus lactis Isolated from Endodontic Infections in Ouagadougou, Burkina Faso.}, journal = {Dentistry journal}, volume = {6}, number = {4}, pages = {}, doi = {10.3390/dj6040069}, pmid = {30544668}, issn = {2304-6767}, abstract = {BACKGROUND: This study aimed to characterize and test the antimicrobial susceptibility of Lactococcus lactis isolated in endodontic infections in Burkina Faso.<br><br>MATERIAL AND METHODS: This was a prospective study conducted at the Municipal Oral Health Center of Ouagadougou, Burkina Faso, from June to October 2014. Clinical data were collected using a questionnaire form. The method of streaking on selective medium was used to isolate bacteria. Identification was made using the API 20 Strep gallery. Antibiotic susceptibility was performed by the diffusion method on solid medium.<br><br>RESULTS: One hundred and twenty-five (125) patients were received with a significant proportion from the age group of 19 to 40 years (55.2%). Apical periodontitis accounted for 50.4% and cellulitis for 49.6% of cases. Lactococcus lactis ssp. lactis was identified in five exudate samples. Isolates were 100% resistant to cefixime and metronidazole, 80% to ceftriaxone, cefuroxime, cefotaxime, chloramphenicol and 60% to penicillin G, amoxicillin, amoxicillin clavulanic acid. A multidrug resistance of more than three families of antibiotics was noticed. No strains produced extended spectrum ß-lactamases.<br><br>CONCLUSION: Lactococcus lactis is part of endodontic biofilm. The reported strong antibiotic resistance involving endodontic therapy will focus on the effect of the disinfectant solution and the mechanical action of the canal instruments.}, }
@article {pmid30544592, year = {2018}, author = {Bosmans, L and Pozo, MI and Verreth, C and Crauwels, S and Wäckers, F and Jacquemyn, H and Lievens, B}, title = {Hibernation Leads to Altered Gut Communities in Bumblebee Queens (Bombus terrestris).}, journal = {Insects}, volume = {9}, number = {4}, pages = {}, doi = {10.3390/insects9040188}, pmid = {30544592}, issn = {2075-4450}, abstract = {Many reptiles, amphibians, mammals, and insects practice some form of hibernation during which their metabolic rate is drastically reduced. This allows them to conserve energy and survive the harsh winter conditions with little or no food. While it can be expected that a reduction in host metabolism has a substantial influence on the gut microbial community, little is known about the effects of hibernation on the composition of the microbial gut community, especially for insects. In this study, we assessed and compared the bacterial gut community composition within the midgut and ileum of indoor-reared queens of Bombus terrestris before and after an artificial hibernation period of 16 weeks. Deep sequencing of 16S ribosomal RNA gene amplicons and clustering of sequence reads into operational taxonomic units (OTUs) at a similarity threshold of 97% revealed several bacterial taxa that are known to be strongly associated with corbiculate bees. Bacterial community composition after hibernation compared to before hibernation was characterized by higher OTU richness and evenness, with decreased levels of the core bacteria Gilliamella (Proteobacteria, Orbaceae) and Snodgrassella (Proteobacteria, Neisseriaceae), and increased relative abundance of non-core bacteria, including several psychrophilic and psychrotrophic taxa.}, }
@article {pmid30544159, year = {2019}, author = {Pedrinho, A and Mendes, LW and Merloti, LF and da Fonseca, MC and Cannavan, FS and Tsai, SM}, title = {Forest-to-pasture conversion and recovery based on assessment of microbial communities in Eastern Amazon rainforest.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {3}, pages = {}, doi = {10.1093/femsec/fiy236}, pmid = {30544159}, issn = {1574-6941}, abstract = {Amazon rainforest has been subjected to particularly high rates of deforestation caused mainly by the expansion of cattle pasture and agriculture. A commonly observed response to land-use change is a negative impact on biodiversity of plant and animal species. However, its effect on the soil microbial community and ecosystem functioning is still poorly understood. Here, we used a DNA metagenomic sequencing approach to investigate the impact of land-use change on soil microbial community composition and its potential functions in three land-use systems (primary forest, pasture and secondary forest) in the Amazon region. In general, the microbial community structure was influenced by changes in soil physicochemical properties. Aluminum and water-holding capacity significantly correlated to overall community structure and most of microbial phyla. Taxonomic changes were followed by potential functional changes in the soil microbial community, with pasture presenting the most distinct profile in comparison with other sites. Although taxonomic structure was very distinct among sites, we observed a recovery of the potential functions in secondary forest after pasture abandonment. Our findings elucidate a significant shift in belowground microbial taxonomic and potential functional diversity following natural forest re-establishment and have implications for ecological restoration programs in tropical and sub-tropical ecosystems.}, }
@article {pmid30542336, year = {2018}, author = {Okazaki, Y and Salcher, MM and Callieri, C and Nakano, SI}, title = {The Broad Habitat Spectrum of the CL500-11 Lineage (Phylum Chloroflexi), a Dominant Bacterioplankton in Oxygenated Hypolimnia of Deep Freshwater Lakes.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2891}, pmid = {30542336}, issn = {1664-302X}, abstract = {CL500-11 (phylum Chloroflexi) is one of the most ubiquitous and abundant bacterioplankton lineages in deep freshwater lakes inhabiting the oxygenated hypolimnion. While metagenomics predicted possible eco-physiological characteristics of this uncultured lineage, no consensus on their ecology has so far been reached, partly because their niche is not clearly understood due to a limited number of quantitative field observations. This study investigated the abundance and distribution of CL500-11 in seven deep perialpine lakes using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). Samples were taken vertically (5-12 depths in each lake) and temporally (in two lakes) at the deepest point of the lakes located in Switzerland, Italy, and Austria with varying depth, trophic state, mixing regime, and water retention time. The results showed a dominance of CL500-11 in all the lakes; their proportion to total prokaryotes ranged from 4.3% (Mondsee) to 24.3% (Lake Garda) and their abundance ranged from 0.65 × 105 (Mondsee) to 1.77 × 105 (Lake Garda) cells mL-1. By summarizing available information on CL500-11 occurrence to date, we demonstrated their broad habitat spectrum, ranging from ultra-oligotrophic to meso-eutrophic lakes, while low abundances or complete absence was observed in lakes with shallow depth, low pH, and/or short water retention time (<1 year). Together with available metagenomic and geochemical evidences from literatures, here we reviewed potential substrates supporting growth of CL500-11. Overall, the present study further endorsed ubiquity and quantitative significance of CL500-11 in deep freshwater systems and narrowed the focus on their physiological characteristics and ecological importance.}, }
@article {pmid30542078, year = {2019}, author = {Scoma, A and Heyer, R and Rifai, R and Dandyk, C and Marshall, I and Kerckhof, FM and Marietou, A and Boshker, HTS and Meysman, FJR and Malmos, KG and Vosegaard, T and Vermeir, P and Banat, IM and Benndorf, D and Boon, N}, title = {Reduced TCA cycle rates at high hydrostatic pressure hinder hydrocarbon degradation and obligate oil degraders in natural, deep-sea microbial communities.}, journal = {The ISME journal}, volume = {13}, number = {4}, pages = {1004-1018}, doi = {10.1038/s41396-018-0324-5}, pmid = {30542078}, issn = {1751-7370}, abstract = {Petroleum hydrocarbons reach the deep-sea following natural and anthropogenic factors. The process by which they enter deep-sea microbial food webs and impact the biogeochemical cycling of carbon and other elements is unclear. Hydrostatic pressure (HP) is a distinctive parameter of the deep sea, although rarely investigated. Whether HP alone affects the assembly and activity of oil-degrading communities remains to be resolved. Here we have demonstrated that hydrocarbon degradation in deep-sea microbial communities is lower at native HP (10 MPa, about 1000 m below sea surface level) than at ambient pressure. In long-term enrichments, increased HP selectively inhibited obligate hydrocarbon-degraders and downregulated the expression of beta-oxidation-related proteins (i.e., the main hydrocarbon-degradation pathway) resulting in low cell growth and CO2 production. Short-term experiments with HP-adapted synthetic communities confirmed this data, revealing a HP-dependent accumulation of citrate and dihydroxyacetone. Citrate accumulation suggests rates of aerobic oxidation of fatty acids in the TCA cycle were reduced. Dihydroxyacetone is connected to citrate through glycerol metabolism and glycolysis, both upregulated with increased HP. High degradation rates by obligate hydrocarbon-degraders may thus be unfavourable at increased HP, explaining their selective suppression. Through lab-scale cultivation, the present study is the first to highlight a link between impaired cell metabolism and microbial community assembly in hydrocarbon degradation at high HP. Overall, this data indicate that hydrocarbons fate differs substantially in surface waters as compared to deep-sea environments, with in situ low temperature and limited nutrients availability expected to further prolong hydrocarbons persistence at deep sea.}, }
@article {pmid30524385, year = {2018}, author = {Rilling, JI and Acuña, JJ and Sadowsky, MJ and Jorquera, MA}, title = {Putative Nitrogen-Fixing Bacteria Associated With the Rhizosphere and Root Endosphere of Wheat Plants Grown in an Andisol From Southern Chile.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2710}, pmid = {30524385}, issn = {1664-302X}, abstract = {Acidic ash derived volcanic soils (Andisols) support 50% of cereal production in Chile. Nitrogen (N) is essential for cereal crops and commonly added as urea with consequent environmental concerns due to leaching. Despite the relevance of N to plant growth, few studies have focused on understanding the application, management and ecological role of N2-fixing bacterial populations as tool for improve the N nutrition of cereal crops in Chile. It is known that N2-fixing bacteria commonly inhabits diverse plant compartments (e.g., rhizosphere and root endosphere) where they can supply N for plant growth. Here, we used culture-independent and dependent approaches to characterize and compare the putative N2-fixing bacteria associated with the rhizosphere and root endosphere of wheat plants grown in an Andisol from southern Chile. Our results showed significantly greater bacterial loads in the rhizosphere than the root endosphere. Quantitative PCR results indicated that the copy number of the 16S rRNA gene ranged from 1012~1013 and 107~108 g-1 sample in rhizosphere and root endosphere, respectively. The nifH gene copy number ranged from 105~106 and 105 g-1 sample in rhizosphere and root endosphere, respectively. The total culturable bacteria number ranged from 109~1010 and 107~108 CFU g-1 sample in rhizosphere and 104~105 and 104 CFU g-1 sample in root endosphere using LB and NM-1 media, respectively. Indirect counts of putative N2-fixing bacteria were 103 and 102~103 CFU g-1 sample in rhizosphere and root endosphere using NFb medium, respectively. Sequencing of 16S rRNA genes from randomly selected putative N2-fixing bacteria revealed the presence of members of Proteobacteria (Bosea and Roseomonas), Actinobacteria (Georgenia, Mycobacterium, Microbacterium, Leifsonia, and Arthrobacter), Bacteroidetes (Chitinophaga) and Firmicutes (Bacillus and Psychrobacillus) taxa. Differences in 16S rRNA and putative nifH-containing bacterial communities between rhizosphere and root endosphere were shown by denaturing gradient gel electrophoresis (DGGE). This study shows a compartmentalization between rhizosphere and root endosphere for both the abundance and diversity of total (16S rRNA) and putative N2-fixing bacterial communities on wheat plants grown in Chilean Andisols. This information can be relevant for the design and application of agronomic strategies to enhance sustainable N-utilization in cereal crops in Chile.}, }
@article {pmid30522433, year = {2018}, author = {Mohr, T and Aliyu, H and Küchlin, R and Zwick, M and Cowan, D and Neumann, A and de Maayer, P}, title = {Comparative genomic analysis of Parageobacillus thermoglucosidasius strains with distinct hydrogenogenic capacities.}, journal = {BMC genomics}, volume = {19}, number = {1}, pages = {880}, pmid = {30522433}, issn = {1471-2164}, support = {031B0180//Bundesministerium für Bildung und Forschung/ ; }, mesh = {Bacterial Proteins/genetics ; Base Sequence ; Carbon Monoxide/chemistry/metabolism ; *Comparative Genomic Hybridization ; Genetic Loci ; *Genome, Bacterial ; Geobacillus/*genetics ; Hydrogen/*metabolism ; Hydrogenase/genetics ; INDEL Mutation ; Multienzyme Complexes/genetics ; Sequence Alignment ; }, abstract = {BACKGROUND: The facultatively anaerobic thermophile Parageobacillus thermoglucosidasius produces hydrogen gas (H2) by coupling CO oxidation to proton reduction in the water-gas shift (WGS) reaction via a carbon monoxide dehydrogenase-hydrogenase enzyme complex. Although little is known about the hydrogenogenic capacities of different strains of this species, these organisms offer a potentially viable process for the synthesis of this alternative energy source.<br><br>RESULTS: The WGS-catalyzed H2 production capacities of four distinct P. thermoglucosidasius strains were determined by cultivation and gas analysis. Three strains (DSM 2542T, DSM 2543 and DSM 6285) were hydrogenogenic, while the fourth strain (DSM 21625) was not. Furthermore, in one strain (DSM 6285) H2 production commenced earlier in the cultivation than the other hydrogenogenic strains. Comparative genomic analysis of the four strains identified extensive differences in the protein complement encoded on the genomes, some of which are postulated to contribute to the different hydrogenogenic capacities of the strains. Furthermore, polymorphisms and deletions in the CODH-NiFe hydrogenase loci may also contribute towards this variable phenotype.<br><br>CONCLUSIONS: Disparities in the hydrogenogenic capacities of different P. thermoglucosidasius strains were identified, which may be correlated to variability in their global proteomes and genetic differences in their CODH-NiFe hydrogenase loci. The data from this study may contribute towards an improved understanding of WGS-catalysed hydrogenogenesis by P. thermoglucosidasius.}, }
@article {pmid30538275, year = {2019}, author = {Nicolás, C and Martin-Bertelsen, T and Floudas, D and Bentzer, J and Smits, M and Johansson, T and Troein, C and Persson, P and Tunlid, A}, title = {The soil organic matter decomposition mechanisms in ectomycorrhizal fungi are tuned for liberating soil organic nitrogen.}, journal = {The ISME journal}, volume = {13}, number = {4}, pages = {977-988}, doi = {10.1038/s41396-018-0331-6}, pmid = {30538275}, issn = {1751-7370}, support = {2013.0073//Knut och Alice Wallenbergs Stiftelse (Knut and Alice Wallenberg Foundation)/ ; }, abstract = {Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.}, }
@article {pmid30536130, year = {2019}, author = {Wilpiszeski, RL and Zhang, Z and House, CH}, title = {Biogeography of thermophiles and predominance of Thermus scotoductus in domestic water heaters.}, journal = {Extremophiles : life under extreme conditions}, volume = {23}, number = {1}, pages = {119-132}, doi = {10.1007/s00792-018-1066-z}, pmid = {30536130}, issn = {1433-4909}, support = {NAI Cooperative agreement #NNA09DA76A//National Aeronautics and Space Administration/ ; }, mesh = {Drinking Water/microbiology ; Heating/*instrumentation ; *Microbiota ; Phylogeography ; RNA, Ribosomal, 16S/genetics ; Thermus/classification/genetics/*isolation &amp; purification ; *Water Microbiology ; }, abstract = {Built systems such as water heaters can harbor extremophiles similar to those residing in natural hot springs, but the extent of colonization is not well understood. To address this, we conducted a survey of thermophilic microorganisms in household water heaters across the United States. Filter samples and inoculated cultures were collected by citizen-scientists from 101 homes. Draft genomes were assembled from cultured isolates and 16S rRNA genes were sequenced from filter samples. 28% of households harbored communities with unambiguous DNA signatures of thermophilic organisms, 36% of households provided viable inocula, and 21% of households had both. All of the recovered cultures as well as the community sequencing results revealed Thermus scotoductus to be the dominant thermophile in domestic water heaters, with a minority of water heaters also containing Meiothermus species and a few containing Aquificae. Sequence distance comparisons show that allopatric speciation does not appear to be a strong control on T. scotoductus distribution. Our results demonstrate that thermophilic organisms are widespread in hot tap water, and that Thermus scotoductus preferentially colonizes water heaters at the expense of local environmental Thermus strains.}, }
@article {pmid30535916, year = {2018}, author = {Albecker, MA and Belden, LK and McCoy, MW}, title = {Comparative Analysis of Anuran Amphibian Skin Microbiomes Across Inland and Coastal Wetlands.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1295-9}, pmid = {30535916}, issn = {1432-184X}, support = {DEB 1136640//National Science Foundation/ ; Project No. 2014-R/14-HCE-3//North Carolina SeaGrant/ ; }, abstract = {Amphibians host a community of microbes on their skin that helps resist infectious disease via the dual influence of anti-pathogenic microbial species and emergent community dynamics. Many frogs rely on freshwater habitats, but salinization is rapidly increasing saltwater concentrations in wetlands around the globe, increasing the likelihood that frogs will come into contact with salt-contaminated habitats. Currently, we know little about how increased salt exposure will affect the symbiotic relationship between the skin microbes and frog hosts. To better understand how salt exposure in a natural context affects the frog skin microbiome, we use Hyla cinerea, a North American treefrog species that can inhabit brackish wetlands, to explore three questions. First, we determine the extent that microbial communities in the environment and on frog skin are similar across populations. Second, we assess the microbial species richness and relative abundance on frogs from habitats with different salinity levels to determine how salinity affects the microbiome. Third, we test whether the relative abundances of putatively pathogen-resistant bacterial species differ between frogs from inland and coastal environments. We found that the frog microbiome is more similar among frogs than to the microbial communities found in surface water and soil, but there is overlap between frog skin and the environmental samples. Skin microbial community richness did not differ among populations, but the relative abundances of microbes were different across populations and salinities. We found no differences in the relative abundances of the anti-fungal bacteria Janthinobacterium lividum, the genus Pseudomonas, and Serratia marcescens, suggesting that environmental exposure to saltwater has a limited influence on these putatively beneficial bacterial taxa.}, }
@article {pmid30535915, year = {2018}, author = {Chamizo, S and Adessi, A and Mugnai, G and Simiani, A and De Philippis, R}, title = {Soil Type and Cyanobacteria Species Influence the Macromolecular and Chemical Characteristics of the Polysaccharidic Matrix in Induced Biocrusts.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1305-y}, pmid = {30535915}, issn = {1432-184X}, support = {706351//H2020 Marie Skłodowska-Curie Actions/ ; }, abstract = {Inoculation of soils with cyanobacteria is proposed as a sustainable biotechnological technique for restoration of degraded areas in drylands due to the important role that cyanobacteria and their exopolysaccharides (EPS) play in the environment. So far, few studies have analyzed the macromolecular and chemical characteristics of the polysaccharidic matrix in induced cyanobacterial biocrusts and the scarce existing studies have mainly focused on sandy soil textures. However, the characteristics of the cyanobacterial polysaccharidic matrix may greatly depend on soil type. The objective of this study was to examine the macromolecular distribution and monosaccharidic composition of the polysaccharidic matrix induced by inoculation of two cyanobacterial species common in arid environments, Phormidium ambiguum (non N-fixing) and Scytonema javanicum (N-fixing) in different soil types. S. javanicum promoted a higher release in the soil of the more soluble and less condensed EPS fraction (i.e., the loosely bound EPS fraction, LB-EPS), while P. ambiguum showed a higher release of the less soluble and more condensed EPS fraction (i.e., the tightly bound EPS fraction, TB-EPS). LB-EPSs were mainly composed of low MW molecules (< 50 kDa), while TB-EPSs were mainly composed of high MW molecules (1100-2000 kDa). The two EPS fractions showed a complex monosaccharidic composition (from 11 to 12 different types of monosaccharides), with glucose as the most abundant monosaccharide, in particular in the poorer soils characterized by lower organic C contents. In more C-rich soils, high abundances of galactose, mannose, and xylose were also found. Low abundance of uronic acids and hydrophobic monosaccharides, such as fucose and rhamnose, was found in the EPS extracted from the inoculated soils. Our results point to the influence of soil type on the macromolecular distribution and monosaccharide composition of the polysaccharidic matrix in induced biocrusts, which is likely to affect biocrust development and their role in soil structure and nutrient cycling in restored dryland soils.}, }
@article {pmid30535914, year = {2018}, author = {Muthukrishnan, T and Al Khaburi, M and Abed, RMM}, title = {Fouling Microbial Communities on Plastics Compared with Wood and Steel: Are They Substrate- or Location-Specific?.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1303-0}, pmid = {30535914}, issn = {1432-184X}, support = {SQU-GCC/CL/17/02//Sultan Qaboos University/ ; }, abstract = {Although marine biofouling has been widely studied on different substrates, information on biofouling on plastics in the Arabian Gulf is limited. Substrate- and location-specific effects were investigated by comparing the microbial communities developed on polyethylene terephthalate (PET) and polyethylene (PE) with those on steel and wood, at two locations in the Sea of Oman. Total biomass was lower on PET and PE than on steel and wood. PET had the highest bacterial abundance at both locations, whereas chlorophyll a concentrations did not vary between substrates. MiSeq 16S ribosomal RNA sequencing revealed comparable operational taxonomic unit (OTU) richness on all substrates at one location but lower numbers on PET and PE at the other location. Non-metric multidimensional scaling (NMDS) showed distinct clusters of the bacterial communities based on substrate (analysis of similarity (ANOSIM), R = 0.45-0.97, p < 0.03) and location (ANOSIM, R = 0.56, p < 0.0001). The bacterial genera Microcystis and Hydrogenophaga and the diatoms Licmophora and Mastogloia were specifically detected on plastics. Desulfovibrio and Pseudomonas spp. exhibited their highest abundance on steel and Corynebacterium spp. on wood. Scanning electron microscopy (SEM) revealed fissure formation on PET and PE, indicating physical degradation. The presence of free radicals on PET and carbonyl bonds (C=O) on PE, as revealed by Fourier transform infrared (FTIR) spectroscopy, indicated abiotic degradation while hydroxyl groups and spectral peaks for proteins and polysaccharides on PE indicated biotic degradation. We conclude that fouling microbial communities are not only substrate-specific but also location-specific and microbes developing on plastics could potentially contribute to their degradation in the marine environment.}, }
@article {pmid30535652, year = {2018}, author = {Whittle, A and Amesbury, MJ and Charman, DJ and Hodgson, DA and Perren, BB and Roberts, SJ and Gallego-Sala, AV}, title = {Salt-Enrichment Impact on Biomass Production in a Natural Population of Peatland Dwelling Arcellinida and Euglyphida (Testate Amoebae).}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1296-8}, pmid = {30535652}, issn = {1432-184X}, support = {NE/L002434/1//Natural Environment Research Council/ ; }, abstract = {Unicellular free-living microbial eukaryotes of the order Arcellinida (Tubulinea; Amoebozoa) and Euglyphida (Cercozoa; SAR), commonly termed testate amoebae, colonise almost every freshwater ecosystem on Earth. Patterns in the distribution and productivity of these organisms are strongly linked to abiotic conditions-particularly moisture availability and temperature-however, the ecological impacts of changes in salinity remain poorly documented. Here, we examine how variable salt concentrations affect a natural community of Arcellinida and Euglyphida on a freshwater sub-Antarctic peatland. We principally report that deposition of wind-blown oceanic salt-spray aerosols onto the peatland surface corresponds to a strong reduction in biomass and to an alteration in the taxonomic composition of communities in favour of generalist taxa. Our results suggest novel applications of this response as a sensitive tool to monitor salinisation of coastal soils and to detect salinity changes within peatland palaeoclimate archives. Specifically, we suggest that these relationships could be used to reconstruct millennial scale variability in salt-spray deposition-a proxy for changes in wind-conditions-from sub-fossil communities of Arcellinida and Euglyphida preserved in exposed coastal peatlands.}, }
@article {pmid30535561, year = {2019}, author = {Rydzanicz, K and Golab, E and Rozej-Bielicka, W and Masny, A}, title = {Screening of mosquitoes for filarioid helminths in urban areas in south western Poland-common patterns in European Setaria tundra xenomonitoring studies.}, journal = {Parasitology research}, volume = {118}, number = {1}, pages = {127-138}, doi = {10.1007/s00436-018-6134-x}, pmid = {30535561}, issn = {1432-1955}, mesh = {Aedes/*parasitology/physiology ; Animals ; Culex/*parasitology/physiology ; Dirofilaria immitis/genetics/*isolation &amp; purification ; Dirofilaria repens/genetics/*isolation &amp; purification ; Dirofilariasis/epidemiology/parasitology/*transmission ; Humans ; Mosquito Vectors/*parasitology/physiology ; Poland/epidemiology ; Setaria Nematode/genetics/*isolation &amp; purification ; Setariasis/epidemiology/parasitology/*transmission ; }, abstract = {In recent years, numerous studies screening mosquitoes for filarioid helminths (xenomonitoring) have been performed in Europe. The entomological monitoring of filarial nematode infections in mosquitoes by molecular xenomonitoring might serve as the measure of the rate at which humans and animals expose mosquitoes to microfilariae and the rate at which animals and humans are exposed to the bites of the infected mosquitoes. We hypothesized that combining the data obtained from molecular xenomonitoring and phenological studies of mosquitoes in the urban environment would provide insights into the transmission risk of filarial diseases. In our search for Dirofilaria spp.-infected mosquitoes, we have found Setaria tundra-infected ones instead, as in many other European studies. We have observed that cross-reactivity in PCR assays for Dirofilaria repens, Dirofilaria immitis, and S. tundra COI gene detection was the rule rather than the exception. S. tundra infections were mainly found in Aedes mosquitoes. The differences in the diurnal rhythm of Aedes and Culex mosquitoes did not seem a likely explanation for the lack of S. tundra infections in Culex mosquitoes. The similarity of S. tundra COI gene sequences found in Aedes vexans and Aedes caspius mosquitoes and in roe deer in many European studies, supported by data on Ae. vexans biology, suggested host preference as the most likely cause of the mosquito genus-biased infections. High diversity of the COI gene sequences isolated in the city of Wroclaw in south western Poland and the presence of identical or almost identical sequences in mosquitoes and roe deer across Europe suggests that S. tundra has been established in most of Europe for a very long time.}, }
@article {pmid30535196, year = {2019}, author = {Kolora, SRR and Weigert, A and Saffari, A and Kehr, S and Walter Costa, MB and Spröer, C and Indrischek, H and Chintalapati, M and Lohse, K and Doose, G and Overmann, J and Bunk, B and Bleidorn, C and Grimm-Seyfarth, A and Henle, K and Nowick, K and Faria, R and Stadler, PF and Schlegel, M}, title = {Divergent evolution in the genomes of closely related lacertids, Lacerta viridis and L. bilineata, and implications for speciation.}, journal = {GigaScience}, volume = {8}, number = {2}, pages = {}, doi = {10.1093/gigascience/giy160}, pmid = {30535196}, issn = {2047-217X}, abstract = {BACKGROUND: Lacerta viridis and Lacerta bilineata are sister species of European green lizards (eastern and western clades, respectively) that, until recently, were grouped together as the L. viridis complex. Genetic incompatibilities were observed between lacertid populations through crossing experiments, which led to the delineation of two separate species within the L. viridis complex. The population history of these sister species and processes driving divergence are unknown. We constructed the first high-quality de novo genome assemblies for both L. viridis and L. bilineata through Illumina and PacBio sequencing, with annotation support provided from transcriptome sequencing of several tissues. To estimate gene flow between the two species and identify factors involved in reproductive isolation, we studied their evolutionary history, identified genomic rearrangements, detected signatures of selection on non-coding RNA, and on protein-coding genes.<br><br>FINDINGS: Here we show that gene flow was primarily unidirectional from L. bilineata to L. viridis after their split at least 1.15 million years ago. We detected positive selection of the non-coding repertoire; mutations in transcription factors; accumulation of divergence through inversions; selection on genes involved in neural development, reproduction, and behavior, as well as in ultraviolet-response, possibly driven by sexual selection, whose contribution to reproductive isolation between these lacertid species needs to be further evaluated.<br><br>CONCLUSION: The combination of short and long sequence reads resulted in one of the most complete lizard genome assemblies. The characterization of a diverse array of genomic features provided valuable insights into the demographic history of divergence among European green lizards, as well as key species differences, some of which are candidates that could have played a role in speciation. In addition, our study generated valuable genomic resources that can be used to address conservation-related issues in lacertids.}, }
@article {pmid30534614, year = {2018}, author = {Rampelli, S and Guenther, K and Turroni, S and Wolters, M and Veidebaum, T and Kourides, Y and Molnár, D and Lissner, L and Benitez-Paez, A and Sanz, Y and Fraterman, A and Michels, N and Brigidi, P and Candela, M and Ahrens, W}, title = {Pre-obese children's dysbiotic gut microbiome and unhealthy diets may predict the development of obesity.}, journal = {Communications biology}, volume = {1}, number = {}, pages = {222}, pmid = {30534614}, issn = {2399-3642}, abstract = {It is widely accepted that the intestinal microbiome is connected to obesity, as key mediator of the diet impact on the host metabolic and immunological status. To investigate whether the individual gut microbiome has a potential in predicting the onset and progression of diseases, here we characterized the faecal microbiota of 70 children in a two-time point prospective study, within a four-year window. All children had normal weight at the beginning of this study, but 36 of them gained excessive weight at the subsequent check-up. Microbiome data were analysed together with the hosts' diet information, physical activity, and inflammatory parameters. We find that the gut microbiota structures were stratified into a discrete number of groups, characterized by different biodiversity that correlates with inflammatory markers and dietary habits, regardless of age, gender, and body weight. Collectively, our data underscore the importance of the microbiome-host-diet configuration as a possible predictor of obesity.}, }
@article {pmid30534120, year = {2018}, author = {Heijboer, A and de Ruiter, PC and Bodelier, PLE and Kowalchuk, GA}, title = {Modulation of Litter Decomposition by the Soil Microbial Food Web Under Influence of Land Use Change.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2860}, pmid = {30534120}, issn = {1664-302X}, abstract = {Soil microbial communities modulate soil organic matter (SOM) dynamics by catalyzing litter decomposition. However, our understanding of how litter-derived carbon (C) flows through the microbial portion of the soil food web is far from comprehensive. This information is necessary to facilitate reliable predictions of soil C cycling and sequestration in response to a changing environment such as land use change in the form of agricultural abandonment. To examine the flow of litter-derived C through the soil microbial food web and it's response to land use change, we carried out an incubation experiment with soils from six fields; three recently abandoned and three long term abandoned fields. In these soils, the fate of 13C-labeled plant litter was followed by analyzing phospholipid fatty acids (PLFA) over a period of 56 days. The litter-amended soils were sampled over time to measure 13CO2 and mineral N dynamics. Microbial 13C-incorporation patterns revealed a clear succession of microbial groups during litter decomposition. Fungi were first to incorporate 13C-label, followed by G- bacteria, G+ bacteria, actinomycetes and micro-fauna. The order in which various microbial groups responded to litter decomposition was similar across all the fields examined, with no clear distinction between recent and long-term abandoned soils. Although the microbial biomass was initially higher in long-term abandoned soils, the net amount of 13C-labeled litter that was incorporated by the soil microbial community was ultimately comparable between recent and long-term abandoned fields. In relative terms, this means there was a higher efficiency of litter-derived 13C-incorporation in recent abandoned soil microbial communities compared to long-term abandoned soils, most likely due to a net shift from SOM-derived C toward root-derived C input in the soil microbial food web following land-abandonment.}, }
@article {pmid30533919, year = {2018}, author = {Kim, SJ and Park, SJ and Kim, JG and Jung, MY and Gwak, JH and Rhee, SK}, title = {Draft Genome Sequence of &quot;Candidatus Izimaplasma sp.&quot; Strain ZiA1, Obtained from a Toluene-Degrading and Iron-Reducing Enrichment Culture.}, journal = {Microbiology resource announcements}, volume = {7}, number = {8}, pages = {}, pmid = {30533919}, issn = {2576-098X}, abstract = {Here, we report the draft genome sequence of &quot;Candidatus Izimaplasma sp.&quot; strain ZiA1 (1.88 Mb and 29.6% G+C content). Strain ZiA1 was cocultured with iron-reducing and toluene-degrading bacteria in an enrichment culture from tidal flat sediment. Like the genomes of other strains of &quot;Ca. Izimaplasma,&quot; the ZiA1 genome contained genes required for anaerobic fermentation.}, }
@article {pmid30532956, year = {2019}, author = {Zhao, Y and Su, JQ and Ye, J and Rensing, C and Tardif, S and Zhu, YG and Brandt, KK}, title = {AsChip: A High-Throughput qPCR Chip for Comprehensive Profiling of Genes Linked to Microbial Cycling of Arsenic.}, journal = {Environmental science &amp; technology}, volume = {53}, number = {2}, pages = {798-807}, doi = {10.1021/acs.est.8b03798}, pmid = {30532956}, issn = {1520-5851}, abstract = {Arsenic (As) is a ubiquitous toxic element adversely affecting human health. Microbe-mediated cycling of As is largely mediated by detoxification and energy metabolism in microorganisms. We here report the development of a novel high-throughput qPCR (HT-qPCR) chip (AsChip) for comprehensive profiling of genes involved in microbial As cycling (here collectively termed &quot;As genes&quot;). AsChip contained 81 primer sets targeting 19 As genes and the 16S rRNA gene as a reference gene. Gene amplicon sequencing showed high identity (>96%) of newly designed primers corresponding to their targets. AsChip displayed high sensitivity (plasmid template serial dilution test; r = -0.99), with more than 96% of all PCR assays yielding true positive signals. R2 coefficients for standard curves and PCR amplification efficiencies averaged 0.98 and 0.99, respectively. A high correlation between CT values obtained by AsChip and conventional qPCR was obtained (r = 0.962, P < 0.001). Finally, we successfully applied AsChip on soil samples from a chromium-copper-arsenic-contaminated field site and identified diverse As genes with total abundance average of 0.4 As gene copies per 16S rRNA. Our results indicate that AsChip constitutes a robust tool for comprehensive quantitative profiling of As genes in environmental samples.}, }
@article {pmid30532746, year = {2018}, author = {Bachmann, J and Heimbach, T and Hassenrück, C and Kopprio, GA and Iversen, MH and Grossart, HP and Gärdes, A}, title = {Environmental Drivers of Free-Living vs. Particle-Attached Bacterial Community Composition in the Mauritania Upwelling System.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2836}, pmid = {30532746}, issn = {1664-302X}, abstract = {Saharan dust input and seasonal upwelling along North-West Africa provide a model system for studying microbial processes related to the export and recycling of nutrients. This study offers the first molecular characterization of prokaryotic particle-attached (PA; >3.0 μm) and free-living (FL; 0.2-3.0 μm) players in this important ecosystem during August 2016. Environmental drivers for alpha-diversity, bacterial community composition, and differences between FL and PA fractions were identified. The ultra-oligotrophic waters off Senegal were dominated by Cyanobacteria while higher relative abundances of Alphaproteobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes (known particle-degraders) occurred in the upwelling area. Temperature, proxy for different water masses, was the best predictor for changes in FL communities. PA community variation was best explained by temperature and ammonium. Bray Curtis dissimilarities between FL and PA were generally very high and correlated with temperature and salinity in surface waters. Greatest similarities between FL and PA occurred at the deep chlorophyll maximum, where bacterial substrate availability was likely highest. This indicates that environmental drivers do not only influence changes among FL and PA communities but also differences between them. This could provide an explanation for contradicting results obtained by different studies regarding the dissimilarity/similarity between FL and PA communities and their biogeochemical functions.}, }
@article {pmid30532651, year = {2018}, author = {Haruta, S and Yamamoto, K}, title = {Model Microbial Consortia as Tools for Understanding Complex Microbial Communities.}, journal = {Current genomics}, volume = {19}, number = {8}, pages = {723-733}, pmid = {30532651}, issn = {1389-2029}, abstract = {A major biological challenge in the postgenomic era has been untangling the composition and functions of microbes that inhabit complex communities or microbiomes. Multi-omics and modern bioinformatics have provided the tools to assay molecules across different cellular and community scales; however, mechanistic knowledge over microbial interactions often remains elusive. This is due to the immense diversity and the essentially undiminished volume of not-yet-cultured microbes. Simplified model communities hold some promise in enabling researchers to manage complexity so that they can mechanistically understand the emergent properties of microbial community interactions. In this review, we surveyed several approaches that have effectively used tractable model consortia to elucidate the complex behavior of microbial communities. We go further to provide some perspectives on the limitations and new opportunities with these approaches and highlight where these efforts are likely to lead as advances are made in molecular ecology and systems biology.}, }
@article {pmid30532562, year = {2018}, author = {Eze, EC and Chenia, HY and El Zowalaty, ME}, title = {Acinetobacter baumannii biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {2277-2299}, pmid = {30532562}, issn = {1178-6973}, abstract = {Acinetobacter baumannii is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. A. baumannii has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units. The interplay among microbial physicochemistry, alterations in the phenotype and genotypic determinants, and the impact of existing ecological niche and the chemistry of antimicrobial agents has led to enhanced biofilm formation resulting in limited access of drugs to their specific targets. Understanding the triggers to biofilm formation is a step towards limiting and containing biofilm-associated infections and development of biofilm-specific countermeasures. The present review therefore focused on explaining the impact of environmental factors, antimicrobial resistance, gene alteration and regulation, and the prevailing microbial ecology in A. baumannii biofilm formation and gives insights into prospective anti-infective treatments.}, }
@article {pmid30530706, year = {2019}, author = {Holman, DB and Bearson, BL and Allen, HK and Shippy, DC and Loving, CL and Kerr, BJ and Bearson, SMD and Brunelle, BW}, title = {Chlortetracycline Enhances Tonsil Colonization and Fecal Shedding of Multidrug-Resistant Salmonella enterica Serovar Typhimurium DT104 without Major Alterations to the Porcine Tonsillar and Intestinal Microbiota.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {4}, pages = {}, doi = {10.1128/AEM.02354-18}, pmid = {30530706}, issn = {1098-5336}, abstract = {Salmonella spp. are estimated to cause 1.2 million cases of human foodborne illness each year in the United States, and pigs can often be asymptomatically colonized with Salmonella spp. (>50% of farms). Recent reports state that 18.3% of Salmonella enterica serovar Typhimurium isolates are resistant to ≥3 antimicrobial classes, and multidrug-resistant (MDR) strains are associated with an increased hospitalization rate and other complications. Chlortetracycline is commonly used in swine production to prevent/treat various diseases; therefore, chlortetracycline treatment of pigs unknowingly colonized with MDR Salmonella may have collateral effects on Salmonella spp. (and other gut bacteria). In this study, we determined the effect of in-feed chlortetracycline (400 g/ton) on shedding and colonization of pigs challenged with the MDR S Typhimurium strain DT104 (n = 11/group). We also assessed the impact on the fecal microbiota over the 12-day experimental period and on the ileum, cecum, and tonsil microbiota at 7 days postinoculation (dpi). In MDR S Typhimurium-inoculated pigs, chlortetracycline administration significantly increased fecal shedding at 2 dpi (+1.4 log10 CFU/g; P < 0.001) and enhanced tonsil colonization (+3.1 log10 CFU/g; P < 0.001). There were few major alterations detected in the gut or tonsillar microbiota of pigs treated with MDR S Typhimurium and/or chlortetracycline. The tonsillar transcriptome was largely unaffected despite increased colonization by MDR S Typhimurium following inoculation of the chlortetracycline-treated pigs. These results highlight the idea that chlortetracycline administration can enhance shedding and colonization of MDR S Typhimurium in pigs, which could increase the risk of environmental dissemination of MDR Salmonella strains.IMPORTANCESalmonella spp. are an important cause of foodborne illness in North America, and pork products are associated with sporadic cases and outbreaks of human salmonellosis. Isolates of Salmonella may be resistant to multiple antibiotics, and infections with multidrug-resistant (MDR) Salmonella spp. are more difficult to treat, leading to increased hospitalization rates. Swine operations commonly use antimicrobials, such as chlortetracycline, to prevent/treat infections, which may have collateral effects on pig microbial populations. Recently, we demonstrated that chlortetracycline induces the expression of genes associated with pathogenesis and invasion in MDR Salmonella enterica serovar Typhimurium in vitro In our current study, we show increased tonsillar colonization and fecal shedding of the MDR S Typhimurium strain DT104 from pigs administered chlortetracycline. Therefore, pigs unknowingly colonized with multidrug-resistant Salmonella spp. and receiving chlortetracycline for an unrelated infection may be at a greater risk for disseminating MDR Salmonella spp. to other pigs and to humans through environmental or pork product contamination.}, }
@article {pmid30530153, year = {2019}, author = {Macintosh, KA and Chin, J and Jacobs, B and Cordell, D and McDowell, RW and Butler, P and Haygarth, PM and Williams, P and Quinn, JP and O'Flaherty, V and McGrath, JW}, title = {Transforming phosphorus use on the island of Ireland: A model for a sustainable system.}, journal = {The Science of the total environment}, volume = {656}, number = {}, pages = {852-861}, doi = {10.1016/j.scitotenv.2018.11.389}, pmid = {30530153}, issn = {1879-1026}, abstract = {Phosphorus is an essential part of the world food web and a non-substitutable nutrient in all biological systems. Losses of phosphorus occur along the food-supply chain and cause environmental degradation and eutrophication. A key global challenge is to meet rising worldwide food demand while protecting water and environmental quality, and seeking to manage uncertainty around potential future phosphorus price or supply shocks. This paper presents a stakeholder-generated conceptual model of potential transformative change for implementing phosphorus sustainability on the island of Ireland via an 'All-Island Phosphorus Sustainability' workshop. Key transition pathways identified by stakeholders included: incentivising phosphorus recovery, developing collaborative networks to facilitate change, developing markets and value chains for recovered products; implementing data-informed practices on-farm to prevent losses and increase efficiencies, and harmonisation of technologies with end-user needs. A comparable model was previously produced for the North American region. We describe consensus and differences around key priorities between the two regions' conceptual models, and assess how the model produced for the island of Ireland can effect system-wide change and policy moving forward. Many of the transitional pathways and future aspirations presented in both models resonate globally and are highly pertinent to other jurisdictions.}, }
@article {pmid30530129, year = {2019}, author = {Christiaens, MER and Udert, KM and Arends, JBA and Huysman, S and Vanhaecke, L and McAdam, E and Rabaey, K}, title = {Membrane stripping enables effective electrochemical ammonia recovery from urine while retaining microorganisms and micropollutants.}, journal = {Water research}, volume = {150}, number = {}, pages = {349-357}, doi = {10.1016/j.watres.2018.11.072}, pmid = {30530129}, issn = {1879-2448}, abstract = {Ammonia recovery from urine avoids the need for nitrogen removal through nitrification/denitrification and re-synthesis of ammonia (NH3) via the Haber-Bosch process. Previously, we coupled an alkalifying electrochemical cell to a stripping column, and achieved competitive nitrogen removal and energy efficiencies using only electricity as input, compared to other technologies such as conventional column stripping with air. Direct liquid-liquid extraction with a hydrophobic gas membrane could be an alternative to increase nitrogen recovery from urine into the absorbent while minimizing energy requirements, as well as ensuring microbial and micropollutant retention. Here we compared a column with a membrane stripping reactor, each coupled to an electrochemical cell, fed with source-separated urine and operated at 20 A m-2. Both systems achieved similar nitrogen removal rates, 0.34 ± 0.21 and 0.35 ± 0.08 mol N L-1 d-1, and removal efficiencies, 45.1 ± 18.4 and 49.0 ± 9.3%, for the column and membrane reactor, respectively. The membrane reactor improved nitrogen recovery to 0.27 ± 0.09 mol N L-1 d-1 (38.7 ± 13.5%) while lowering the operational (electrochemical and pumping) energy to 6.5 kWhe kg N-1 recovered, compared to the column reactor, which reached 0.15 ± 0.06 mol N L-1 d-1 (17.2 ± 8.1%) at 13.8 kWhe kg N-1. Increased cell concentrations of an autofluorescent E. coli MG1655 + prpsM spiked in the urine influent were observed in the absorbent of the column stripping reactor after 24 h, but not for the membrane stripping reactor. None of six selected micropollutants spiked in the urine were found in the absorbent of both technologies. Overall, the membrane stripping reactor is preferred as it improved nitrogen recovery with less energy input and generated an E. coli- and micropollutant-free product for potential safe reuse. Nitrogen removal rate and efficiency can be further optimized by increasing the NH3 vapor pressure gradient and/or membrane surface area.}, }
@article {pmid30529486, year = {2019}, author = {Labarthe, S and Polizzi, B and Phan, T and Goudon, T and Ribot, M and Laroche, B}, title = {A mathematical model to investigate the key drivers of the biogeography of the colon microbiota.}, journal = {Journal of theoretical biology}, volume = {462}, number = {}, pages = {552-581}, doi = {10.1016/j.jtbi.2018.12.009}, pmid = {30529486}, issn = {1095-8541}, abstract = {The gut microbiota, mainly located in the colon, is engaged in a complex dialogue with the large intestinal epithelium through which important regulatory processes for the health and well-being of the host take place. Imbalances of the microbial populations, called dysbiosis, are related to several pathological status, emphasizing the importance of understanding the gut bacterial ecology. Among the ecological drivers of the microbiota, the spatial structure of the colon is of special interest: spatio-temporal mechanisms can lead to the constitution of spatial interactions among the bacterial populations and of environmental niches that impact the overall colonization of the colon. In the present study, we introduce a mathematical model of the colon microbiota in its fluid environment, based on the explicit coupling of a population dynamics model of microbial populations involved in fibre degradation with a fluid dynamics model of the luminal content. This modeling framework is used to study the main drivers of the spatial structure of the microbiota, specially focusing on the dietary fibre inflow, the epithelial motility, the microbial active swimming and viscosity gradients in the digestive track. We found 1) that the viscosity gradients allow the creation of favorable niches in the vicinity of the mucus layer; 2) that very low microbial active swimming in the radial direction is enough to promote bacterial growth, which sheds a new light on microbial motility in the colon and 3) that dietary fibres are the main driver of the spatial structure of the microbiota in the distal bowel whereas epithelial motility is preponderant for the colonization of the proximal colon; in the transverse colon, fibre levels and chemotaxis have the strongest impact on the distribution of the microbial communities.}, }
@article {pmid30521380, year = {2019}, author = {Calatayud, M and Dezutter, O and Hernandez-Sanabria, E and Hidalgo-Martinez, S and Meysman, FJR and Van de Wiele, T}, title = {Development of a host-microbiome model of the small intestine.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {33}, number = {3}, pages = {3985-3996}, doi = {10.1096/fj.201801414R}, pmid = {30521380}, issn = {1530-6860}, abstract = {The intestinal epithelium plays an essential role in the balance between tolerant and protective immune responses to infectious agents. In vitro models do not typically consider the innate immune response and gut microbiome in detail, so these models do not fully mimic the physiologic aspects of the small intestine. We developed and characterized a long-term in vitro model containing enterocyte, goblet, and immune-like cells exposed to a synthetic microbial community representative of commensal inhabitants of the small intestine. This model showed differential responses toward a synthetic microbial community of commensal bacterial inhabitants of the small intestine in the absence or presence of LPS from Escherichia coli O111:B4. Simultaneous exposure to LPS and microbiota induced impaired epithelial barrier function; increased production of IL-8, IL-6, TNF-α, and C-X-C motif chemokine ligand 16; and augmented differentiation and adhesion of macrophage-like cells and the overexpression of dual oxidase 2 and TLR-2 and -4 mRNA. In addition, the model demonstrated the ability to assess the adhesion of specific bacterial strains from the synthetic microbial community-more specifically, Veillonella parvula-to the simulated epithelium. This novel in vitro model may assist in overcoming sampling and retrieval difficulties when studying host-microbiome interactions in the small intestine.-Calatayud, M., Dezutter, O., Hernandez-Sanabria, E., Hidalgo-Martinez, S., Meysman, F. J. R., Van de Wiele, T. Development of a host-microbiome model of the small intestine.}, }
@article {pmid30520189, year = {2019}, author = {Andeta, AF and Vandeweyer, D and Teffera, EF and Woldesenbet, F and Verreth, C and Crauwels, S and Lievens, B and Vancampenhout, K and Van Campenhout, L}, title = {Effect of fermentation system on the physicochemical and microbial community dynamics during enset (Ensete ventricosum) fermentation.}, journal = {Journal of applied microbiology}, volume = {126}, number = {3}, pages = {842-853}, doi = {10.1111/jam.14173}, pmid = {30520189}, issn = {1365-2672}, support = {VLIR-TEAM ZEIN2015PR407//Vlaamse Interuniversitaire Raad voor Universitaire Ontwikkelingssamen werking' (VLIR-UOS)/ ; }, mesh = {*Fermentation ; *Fermented Foods ; Food Technology/*methods ; *Microbiota ; *Musaceae ; }, abstract = {AIMS: The present study was conducted to assess the effect of three different fermentation systems on fermentation of enset into kocho.<br><br>METHODS AND RESULTS: Nine enset plants were processed, mixed and fermented in either a pit, a bamboo basket or a sauerkraut jar. Samples were taken on days 1, 7, 15, 31, 60 and 90. Moisture content and pH generally decreased and titratable acidity increased during fermentation. Total viable aerobic counts were generally high for all samples and Enterobacteriaceae counts were reduced to below the detectable level after day 1 for the pits and jars and after day 7 for the baskets. Illumina MiSeq sequencing of 16S ribosomal RNA genes revealed that Leuconostoc and Lactococcus spp. were the most abundant lactic acid bacteria in the initial phases of the fermentation. Later on, Lactobacillus, Weissella and Bifidobacterium dominated.<br><br>CONCLUSIONS: The type of fermentation system used had an effect on the microbial dynamics and the effect increased towards the end of fermentation.<br><br>Millions of people in Ethiopia daily consume kocho prepared in either a pit or a basket. These systems show practical problems, but this study shows that fermentation is also possible in a sauerkraut jar.}, }
@article {pmid30518818, year = {2019}, author = {Rosado, PM and Leite, DCA and Duarte, GAS and Chaloub, RM and Jospin, G and Nunes da Rocha, U and P Saraiva, J and Dini-Andreote, F and Eisen, JA and Bourne, DG and Peixoto, RS}, title = {Marine probiotics: increasing coral resistance to bleaching through microbiome manipulation.}, journal = {The ISME journal}, volume = {13}, number = {4}, pages = {921-936}, doi = {10.1038/s41396-018-0323-6}, pmid = {30518818}, issn = {1751-7370}, abstract = {Although the early coral reef-bleaching warning system (NOAA/USA) is established, there is no feasible treatment that can minimize temperature bleaching and/or disease impacts on corals in the field. Here, we present the first attempts to extrapolate the widespread and well-established use of bacterial consortia to protect or improve health in other organisms (e.g., humans and plants) to corals. Manipulation of the coral-associated microbiome was facilitated through addition of a consortium of native (isolated from Pocillopora damicornis and surrounding seawater) putatively beneficial microorganisms for corals (pBMCs), including five Pseudoalteromonas sp., a Halomonas taeanensis and a Cobetia marina-related species strains. The results from a controlled aquarium experiment in two temperature regimes (26 °C and 30 °C) and four treatments (pBMC; pBMC with pathogen challenge - Vibrio coralliilyticus, VC; pathogen challenge, VC; and control) revealed the ability of the pBMC consortium to partially mitigate coral bleaching. Significantly reduced coral-bleaching metrics were observed in pBMC-inoculated corals, in contrast to controls without pBMC addition, especially challenged corals, which displayed strong bleaching signs as indicated by significantly lower photopigment contents and Fv/Fm ratios. The structure of the coral microbiome community also differed between treatments and specific bioindicators were correlated with corals inoculated with pBMC (e.g., Cobetia sp.) or VC (e.g., Ruegeria sp.). Our results indicate that the microbiome in corals can be manipulated to lessen the effect of bleaching, thus helping to alleviate pathogen and temperature stresses, with the addition of BMCs representing a promising novel approach for minimizing coral mortality in the face of increasing environmental impacts.}, }
@article {pmid30506480, year = {2018}, author = {Ascunce, MS and Shin, K and Huguet-Tapia, JC and Poudel, R and Garrett, KA and van Bruggen, AHC and Goss, EM}, title = {Penicillin Trunk Injection Affects Bacterial Community Structure in Citrus Trees.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1302-1}, pmid = {30506480}, issn = {1432-184X}, support = {N/A//Florida Department of Agriculture and Consumer Services/ ; N/A//Institute of Food and Agricultural Sciences/ ; N/A//Esther B. O'Keeffe Foundation/ ; }, abstract = {Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas), an uncultured α-proteobacterium, is the most destructive disease of citrus trees worldwide. In previous studies, trunk injections of penicillin reduced CLas titers and HLB symptoms in citrus. However, antibiotic effects on the whole plant microbial community, which include effects on taxa that interact with CLas, have not yet been addressed. In this study, we investigated the effects of penicillin injection (0, 1000, and 6000 mg L-1) on rhizospheric and endophytic bacterial communities of grapefruit trees in field and greenhouse experiments through culture-independent high-throughput sequencing. DNA extractions from petioles and roots were subjected to 16S rRNA high-throughput sequencing, and reads were clustered by sequence similarity into operational taxonomic units (OTUs). Principal coordinates analysis based on weighted-UniFrac distances did not reveal differences in bacterial communities among treatments in any of the sample sources. However, pairwise linear discriminant analysis indicated significant differences in relative abundance of some taxa (including CLas) among treatments. Network analysis showed that penicillin produced major changes in root bacterial community structure by affecting interspecific microbial associations. This study provides new knowledge of the effect of antimicrobial treatments on interspecific relationships in citrus microbial communities.}, }
@article {pmid30505703, year = {2018}, author = {Ellis, S and Ritz, K}, title = {A modified high-throughput analysis of PLFAs in soil.}, journal = {MethodsX}, volume = {5}, number = {}, pages = {1491-1497}, pmid = {30505703}, issn = {2215-0161}, abstract = {Microbial community profiling via phospholipid fatty-acid (PLFA) analysis is an insightful technique which elucidates the phenotypic structure of microbial assemblages within soil. Previous iterations of PLFA analysis have used large quantities of chemicals and can take extended periods of time to perform. Another barrier to the implementation of this method is the cost and availability of specialised machinery. We report on a high-throughput method which reduces both the time to extract PLFAs from soil and reduces the quantity of chemicals required.}, }
@article {pmid30504896, year = {2019}, author = {Aguilar-Trigueros, CA and Hempel, S and Powell, JR and Cornwell, WK and Rillig, MC}, title = {Bridging reproductive and microbial ecology: a case study in arbuscular mycorrhizal fungi.}, journal = {The ISME journal}, volume = {13}, number = {4}, pages = {873-884}, doi = {10.1038/s41396-018-0314-7}, pmid = {30504896}, issn = {1751-7370}, abstract = {Offspring size is a key trait for understanding the reproductive ecology of species, yet studies addressing the ecological meaning of offspring size have so far been limited to macro-organisms. We consider this a missed opportunity in microbial ecology and provide what we believe is the first formal study of offspring-size variation in microbes using reproductive models developed for macro-organisms. We mapped the entire distribution of fungal spore size in the arbuscular mycorrhizal (AM) fungi (subphylum Glomeromycotina) and tested allometric expectations of this trait to offspring (spore) output and body size. Our results reveal a potential paradox in the reproductive ecology of AM fungi: while large spore-size variation is maintained through evolutionary time (independent of body size), increases in spore size trade off with spore output. That is, parental mycelia of large-spored species produce fewer spores and thus may have a fitness disadvantage compared to small-spored species. The persistence of the large-spore strategy, despite this apparent fitness disadvantage, suggests the existence of advantages to large-spored species that could manifest later in fungal life history. Thus, we consider that solving this paradox opens the door to fruitful future research establishing the relationship between offspring size and other AM life history traits.}, }
@article {pmid30504213, year = {2019}, author = {Zinke, LA and Glombitza, C and Bird, JT and Røy, H and Jørgensen, BB and Lloyd, KG and Amend, JP and Reese, BK}, title = {Microbial Organic Matter Degradation Potential in Baltic Sea Sediments Is Influenced by Depositional Conditions and In Situ Geochemistry.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {4}, pages = {}, doi = {10.1128/AEM.02164-18}, pmid = {30504213}, issn = {1098-5336}, abstract = {Globally, marine sediments are a vast repository of organic matter, which is degraded through various microbial pathways, including polymer hydrolysis and monomer fermentation. The sources, abundances, and quality (i.e., labile or recalcitrant) of the organic matter and the composition of the microbial assemblages vary between sediments. Here, we examine new and previously published sediment metagenomes from the Baltic Sea and the nearby Kattegat region to determine connections between geochemistry and the community potential to degrade organic carbon. Diverse organic matter hydrolysis encoding genes were present in sediments between 0.25 and 67 meters below seafloor and were in higher relative abundances in those sediments that contained more organic matter. New analysis of previously published metatranscriptomes demonstrated that many of these genes were transcribed in two organic-rich Holocene sediments. Some of the variation in deduced pathways in the metagenomes correlated with carbon content and depositional conditions. Fermentation-related genes were found in all samples and encoded multiple fermentation pathways. Notably, genes involved in alcohol metabolism were amongst the most abundant of these genes, indicating that this is an important but underappreciated aspect of sediment carbon cycling. This study is a step towards a more complete understanding of microbial food webs and the impacts of depositional facies on present sedimentary microbial communities.IMPORTANCE Sediments sequester organic matter over geologic time scales and impact global climate regulation. Microbial communities in marine sediments drive organic matter degradation, but the factors controlling their assemblages and activities, which in turn impact their role in organic matter degradation, are not well understood. Hence, determining the role of microbial communities in carbon cycling in various sediment types is necessary for predicting future sediment carbon cycling. We examined microbial communities in Baltic Sea sediments, which were deposited across various climatic and geographical regimes to determine the relationship between microbial potential for breakdown of organic matter and abiotic factors, including geochemistry and sediment lithology. The findings from this study will contribute to our understanding of carbon cycling in the deep biosphere and how microbial communities live in deeply buried environments.}, }
@article {pmid30503875, year = {2018}, author = {Vega, NM and Gore, J}, title = {Simple organizing principles in microbial communities.}, journal = {Current opinion in microbiology}, volume = {45}, number = {}, pages = {195-202}, doi = {10.1016/j.mib.2018.11.007}, pmid = {30503875}, issn = {1879-0364}, mesh = {Animals ; Bacteria/genetics ; Bacterial Infections/microbiology ; *Bacterial Physiological Phenomena ; Humans ; *Microbiota ; Models, Animal ; }, abstract = {There is a great deal of interest in discovering the principles that organize microbial communities, to better understand the structure and diversity of these communities in the natural world. Recent conceptual and technical advances have shown how simple organizing principles can give rise to surprising diversity and complex patterns in these consortia. Understanding competition, cooperation, and communication among microbes has provided novel insights into the structure and behavior of microbial collectives, and the use of simple animal models has advanced our understanding of microbial ecology in the host. These multidisciplinary efforts to understand and predict the properties of microbial communities will be critical in the development of microbial ecology as an applied science.}, }
@article {pmid30502541, year = {2019}, author = {Pannekens, M and Kroll, L and Müller, H and Mbow, FT and Meckenstock, RU}, title = {Oil reservoirs, an exceptional habitat for microorganisms.}, journal = {New biotechnology}, volume = {49}, number = {}, pages = {1-9}, doi = {10.1016/j.nbt.2018.11.006}, pmid = {30502541}, issn = {1876-4347}, mesh = {Archaea/*metabolism ; Bacteria/*metabolism ; *Ecosystem ; Hydrogen-Ion Concentration ; Oil and Gas Fields/*microbiology/virology ; Phylogeny ; Salinity ; }, abstract = {Microorganisms are present in oil reservoirs around the world where they degrade oil and lead to changes in oil quality. Unfortunately, our knowledge about processes in deep oil reservoirs is limited due to the lack of undisturbed samples. In this review, we discuss the distribution of microorganisms at the oil-water transition zone as well as in water saturated parts of the oil leg and their possible physiological adaptations to abiotic and biotic ecological factors such as temperature, salinity and viruses. We show the importance of studying the water phase within the oil, because small water inclusions and pockets within the oil leg provide an exceptional habitat for microorganisms within a natural oil reservoir and concurrently enlarge the zone of oil biodegradation. Environmental factors such as temperature and salinity control oil biodegradation. Temperature determines the type of microorganisms which are able to inhabit the reservoir. Proteobacteria and Euryarchaeota, are ubiquitous in oil reservoirs over all temperature ranges, whereas some others are tied to specific temperatures. It is proposed that biofilm formation is the dominant way of life within oil reservoirs, enhancing nutrient uptake, syntrophic interactions and protection against environmental stress. Literature shows that viruses are abundant in oil reservoirs and the possible impact on microbial community composition due to control of microbial activity and function is discussed.}, }
@article {pmid30515182, year = {2018}, author = {Gil-Martínez, M and López-García, Á and Domínguez, MT and Navarro-Fernández, CM and Kjøller, R and Tibbett, M and Marañón, T}, title = {Ectomycorrhizal Fungal Communities and Their Functional Traits Mediate Plant-Soil Interactions in Trace Element Contaminated Soils.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {1682}, pmid = {30515182}, issn = {1664-462X}, abstract = {There is an increasing consensus that microbial communities have an important role in mediating ecosystem processes. Trait-based ecology predicts that the impact of the microbial communities on ecosystem functions will be mediated by the expression of their traits at community level. The link between the response of microbial community traits to environmental conditions and its effect on plant functioning is a gap in most current microbial ecology studies. In this study, we analyzed functional traits of ectomycorrhizal fungal species in order to understand the importance of their community assembly for the soil-plant relationships in holm oak trees (Quercus ilex subsp. ballota) growing in a gradient of exposure to anthropogenic trace element (TE) contamination after a metalliferous tailings spill. Particularly, we addressed how the ectomycorrhizal composition and morphological traits at community level mediate plant response to TE contamination and its capacity for phytoremediation. Ectomycorrhizal fungal taxonomy and functional diversity explained a high proportion of variance of tree functional traits, both in roots and leaves. Trees where ectomycorrhizal fungal communities were dominated by the abundant taxa Hebeloma cavipes and Thelephora terrestris showed a conservative root economics spectrum, while trees colonized by rare taxa presented a resource acquisition strategy. Conservative roots presented ectomycorrhizal functional traits characterized by high rhizomorphs formation and low melanization which may be driven by resource limitation. Soil-to-root transfer of TEs was explained substantially by the ectomycorrhizal fungal species composition, with the highest transfer found in trees whose roots were colonized by Hebeloma cavipes. Leaf phosphorus was related to ectomycorrhizal species composition, specifically higher leaf phosphorus was related to the root colonization by Thelephora terrestris. These findings support that ectomycorrhizal fungal community composition and their functional traits mediate plant performance in metal-contaminated soils, and have a high influence on plant capacity for phytoremediation of contaminants. The study also corroborates the overall effects of ectomycorrhizal fungi on ecosystem functioning through their mediation over the plant economics spectrum.}, }
@article {pmid30514367, year = {2018}, author = {Marasco, R and Mosqueira, MJ and Fusi, M and Ramond, JB and Merlino, G and Booth, JM and Maggs-Kölling, G and Cowan, DA and Daffonchio, D}, title = {Rhizosheath microbial community assembly of sympatric desert speargrasses is independent of the plant host.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {215}, pmid = {30514367}, issn = {2049-2618}, mesh = {Actinobacteria/classification/genetics/isolation &amp; purification ; Alphaproteobacteria/classification/genetics/isolation &amp; purification ; Ascomycota/classification/genetics/isolation &amp; purification ; Bacteria/classification/*isolation &amp; purification ; DNA, Bacterial/genetics ; DNA, Fungal/genetics ; Desert Climate ; Fungi/classification/*isolation &amp; purification ; Metagenomics/*methods ; Phylogeny ; Plant Roots/microbiology ; Poaceae/*microbiology ; Rhizosphere ; Sequence Analysis, DNA ; Soil Microbiology ; }, abstract = {BACKGROUND: The rhizosheath-root system is an adaptive trait of sandy-desert speargrasses in response to unfavourable moisture and nutritional conditions. Under the deserts' polyextreme conditions, plants interact with edaphic microorganisms that positively affect their fitness and resistance. However, the trophic simplicity and environmental harshness of desert ecosystems have previously been shown to strongly influence soil microbial community assembly. We hypothesize that sand-driven ecological filtering constrains the microbial recruitment processes in the speargrass rhizosheath-root niche, prevailing over the plant-induced selection.<br><br>METHODS: Bacterial and fungal communities from the rhizosheath-root compartments (endosphere root tissues, rhizosheath and rhizosphere) of three Namib Desert speargrass species (Stipagrostis sabulicola, S. seelyae and Cladoraphis spinosa) along with bulk sand have been studied to test our hypothesis. To minimize the variability determined by edaphic and climatic factors, plants living in a single dune were studied. We assessed the role of plant species vs the sandy substrate on the recruitment and selection, phylogenetic diversity and co-occurrence microbial networks of the rhizosheath-root system microbial communities.<br><br>RESULTS: Microorganisms associated with the speargrass rhizosheath-root system were recruited from the surrounding bulk sand population and were significantly enriched in the rhizosheath compartments (105 and 104 of bacterial 16S rRNA and fungal ITS copies per gram of sand to up to 108 and 107 copies per gram, respectively). Furthermore, each rhizosheath-root system compartment hosted a specific microbial community demonstrating strong niche-partitioning. The rhizosheath-root systems of the three speargrass species studied were dominated by desert-adapted Actinobacteria and Alphaproteobacteria (e.g. Lechevalieria, Streptomyces and Microvirga) as well as saprophytic Ascomycota fungi (e.g. Curvularia, Aspergillus and Thielavia). Our results clearly showed a random phylogenetic turnover of rhizosheath-root system associated microbial communities, independent of the plant species, where stochastic factors drive neutral assembly. Co-occurrence network analyses also indicated that the bacterial and fungal community members of the rhizosheath-root systems established a higher number of interactions than those in the barren bulk sand, suggesting that the former are more stable and functional than the latter.<br><br>CONCLUSION: Our study demonstrates that the rhizosheath-root system microbial communities of desert dune speargrasses are stochastically assembled and host-independent. This finding supports the concept that the selection determined by the desert sand prevails over that imposed by the genotype of the different plant species.}, }
@article {pmid30512194, year = {2019}, author = {Petrovich, ML and Rosenthal, AF and Griffin, JS and Wells, GF}, title = {Spatially resolved abundances of antibiotic resistance genes and intI1 in wastewater treatment biofilms.}, journal = {Biotechnology and bioengineering}, volume = {116}, number = {3}, pages = {543-554}, doi = {10.1002/bit.26887}, pmid = {30512194}, issn = {1097-0290}, support = {C-060//Chicago Community Trust, Chicago Biomedical Consortium Catalyst/ ; //Northwestern University/ ; }, abstract = {Attached growth bioprocesses that use biofilms to remove organic matter or nutrients from wastewater are known to harbor antibiotic resistance genes (ARGs). Biofilms in these processes are spatially heterogeneous, but little is known about depth stratification of ARGs in complex, mixed culture biofilms. To address this knowledge gap, we used an experimental approach combining cryosectioning and quantitative polymerase chain reaction to quantify the spatial distribution of three ARGs (sul1, ermB, and qnrS) and the class 1 integron-integrase gene intI1 in biofilms from a lab-scale rotating annular reactor fed with synthetic wastewater. We also used high throughput 16S ribosomal RNA (rRNA) gene sequencing to characterize community structure with depth in biofilms. The ARG sul1 and the integron-integrase gene intI1 were found in higher abundances in upper layers of biofilm near the fluid-biofilm interface than in lower layers and exhibited significant correlations between the distance from substratum and gene abundances. The genes ermB and qnrS were present in comparatively low relative abundances. Microbial community structure varied significantly by date of sampling and distance from the substratum. These findings highlight the genetic and taxonomic heterogeneity with distance from substratum in wastewater treatment biofilms and show that sul1 and intI1 are particularly abundant near fluid-biofilm interfaces where cells are most likely to detach and flow into downstream portions of treatment systems and can ultimately be released into the environment through effluent.}, }
@article {pmid30502606, year = {2019}, author = {Xiong, Z and Hussain, A and Lee, J and Lee, HS}, title = {Food waste fermentation in a leach bed reactor: Reactor performance, and microbial ecology and dynamics.}, journal = {Bioresource technology}, volume = {274}, number = {}, pages = {153-161}, doi = {10.1016/j.biortech.2018.11.066}, pmid = {30502606}, issn = {1873-2976}, abstract = {Food waste fermentation was investigated in a leach bed reactor operated at acidic, neutral and alkaline conditions. Highest solids reduction of 87% was obtained at pH 7 in 14 days of reaction time with minimum mixing. The concentration of volatile fatty acids increased to 28.6 g COD/L under pH 7, while the highest butyric acid of 16 g COD/L was obtained at pH 6. Bacterial community structure was narrowed down to Bifidobacterium and Clostridium at pH 6, while Bacteroides and Dysgonomonas were identified as main players at both pH 7 and 8. Bacterial populations in the food residue generally reflected those in the leachate, but some bacteria were selectively enriched in the leachate or the food residue. Bacterial community dynamics suggested that biodegradable food waste was first fermented by one of dominant players (e.g., Clostridium) and the other degraded resistant dietary fibers later (e.g., Bifidobacterium, Bacteroides, Dysgonomonas).}, }
@article {pmid30500479, year = {2019}, author = {Kothamasi, D and Wannijn, J and Van Hees, M and Nauts, R and Van Gompel, A and Vanhoudt, N and Vandenhove, H}, title = {Exposure to ionizing radiation affects the growth of ectomycorrhizal fungi and induces increased melanin production and increased capacities of reactive oxygen species scavenging enzymes.}, journal = {Journal of environmental radioactivity}, volume = {197}, number = {}, pages = {16-22}, doi = {10.1016/j.jenvrad.2018.11.005}, pmid = {30500479}, issn = {1879-1700}, mesh = {Basidiomycota ; Cesium Radioisotopes ; Ecosystem ; Fungi ; Melanins/*metabolism ; Mycorrhizae/enzymology/growth &amp; development/*radiation effects ; *Radiation, Ionizing ; Reactive Oxygen Species/metabolism ; }, abstract = {Ectomycorrhizal (EM) fungi form symbioses with dominant tree families in boreal, temperate and tropical ecosystems and are important drivers of ecosystem function. EM fungal hyphae extend over a large area making them susceptible to enhanced radiation levels from naturally occurring or anthropogenically originating radioisotopes in the rhizosphere. In this study, the in-vitro effects of ionizing radiation on the growth and biomass of EM fungi Suillus luteus, S. bovinus and Rhizopogon luteolus were investigated. EM fungal cultures were exposed to gamma radiation from a 137Cs source for 137 h in darkness at 21 °C at dose rates of 404, 108.5 and 54.9 mGy h-1 resulting in total absorbed doses of 55.21, 14.82 and 7.50 Gy respectively. Cultures grown in the dark at 21 °C but not exposed to the 137Cs source served as the control. Our results show that EM fungi vary in their sensitivity to ionizing radiation. EM fungi used in this study produced melanin and reactive oxygen species scavenging enzymes such as catalase and superoxide dismutase as a response to ionizing radiation.}, }
@article {pmid30499007, year = {2018}, author = {Maillard, F and Leduc, V and Bach, C and de Moraes Gonçalves, JL and Androte, FD and Saint-André, L and Laclau, JP and Buée, M and Robin, A}, title = {Microbial Enzymatic Activities and Community-Level Physiological Profiles (CLPP) in Subsoil Layers Are Altered by Harvest Residue Management Practices in a Tropical Eucalyptus grandis Plantation.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1298-6}, pmid = {30499007}, issn = {1432-184X}, abstract = {Harvest residue management is a key issue for the sustainability of Eucalyptus plantations established on poor soils. Soil microbial communities contribute to soil fertility by the decomposition of the organic matter (OM), but little is known about the effect of whole-tree harvesting (WTH) in comparison to stem only harvesting (SOH) on soil microbial functional diversity in Eucalyptus plantations. We studied the effects of harvest residue management (branches, leaves, bark) of Eucalyptus grandis trees on soil enzymatic activities and community-level physiological profiles in a Brazilian plantation. We measured soil microbial enzymatic activities involved in OM decomposition and we compared the community level physiological profiles (CLPP) of the soil microbes in WTH and SOH plots. WTH decreased enzyme activities and catabolic potential of the soil microbial community. Furthermore, these negative effects on soil functional diversity were mainly observed below the 0-5 cm layer (5-10 and 10-20 cm), suggesting that WTH can be harmful to the soil health in these plantations.}, }
@article {pmid30498637, year = {2018}, author = {Honeyman, AS and Day, ML and Spear, JR}, title = {Regional fresh snowfall microbiology and chemistry are driven by geography in storm-tracked events, Colorado, USA.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5961}, pmid = {30498637}, issn = {2167-8359}, abstract = {Snowfall is a global phenomenon highly integrated with hydrology and ecology. Forays into studying bioaerosols and their dependence on aeolian movement are largely constrained to either precipitation-independent analyses or in silico models. Though snowpack and glacial microbiological studies have been conducted, little is known about the biological component of meteoric snow. Through culture-independent phylogenetic and geochemical analyses, we show that the geographical location at which snow precipitates determines snowfall's geochemical and microbiological composition. Storm-tracking, furthermore, can be used as a valuable environmental indicator to trace down what factors are influencing bioaerosols. We estimate annual aeolian snowfall deposits of up to ∼10 kg of bacterial/archaeal biomass per hectare along our study area of the eastern Front Range in Colorado. The dominant kinds of microbiota captured in an analysis of seven snow events at two different locations, one urban, one rural, across the winter of 2016/2017 included phyla Proteobacteria, Bacteroidetes, Firmicutes, and Acidobacteria, though a multitude of different kinds of organisms were found in both. Taxonomically, Bacteroidetes were more abundant in Golden (urban plain) snow while Proteobacteria were more common in Sunshine (rural mountain) samples. Chemically, Golden snowfall was positively correlated with some metals and anions. The work also hints at better informing the &quot;everything is everywhere&quot; hypotheses of the microbial world and that atmospheric transport of microbiota is not only common, but is capable of disseminating vast amounts of microbiota of different physiologies and genetics that then affect ecosystems globally. Snowfall, we conclude, is a significant repository of microbiological material with strong implications for both ecosystem genetic flux and general bio-aerosol theory.}, }
@article {pmid30498561, year = {2018}, author = {Sakoula, D and Nowka, B and Spieck, E and Daims, H and Lücker, S}, title = {The draft genome sequence of &quot;Nitrospira lenta&quot; strain BS10, a nitrite oxidizing bacterium isolated from activated sludge.}, journal = {Standards in genomic sciences}, volume = {13}, number = {}, pages = {32}, pmid = {30498561}, issn = {1944-3277}, support = {339880//European Research Council/International ; }, abstract = {The genus Nitrospira is considered to be the most widespread and abundant group of nitrite-oxidizing bacteria in many natural and man-made ecosystems. However, the ecophysiological versatility within this phylogenetic group remains highly understudied, mainly due to the lack of pure cultures and genomic data. To further expand our understanding of this biotechnologically important genus, we analyzed the high quality draft genome of &quot;Nitrospira lenta&quot; strain BS10, a sublineage II Nitrospira that was isolated from a municipal wastewater treatment plant in Hamburg, Germany. The genome of &quot;N. lenta&quot; has a size of 3,756,190 bp and contains 3968 genomic objects, of which 3907 are predicted protein-coding sequences. Thorough genome annotation allowed the reconstruction of the &quot;N. lenta&quot; core metabolism for energy conservation and carbon fixation. Comparative analyses indicated that most metabolic features are shared with N. moscoviensis and &quot;N. defluvii&quot;, despite their ecological niche differentiation and phylogenetic distance. In conclusion, the genome of &quot;N. lenta&quot; provides important insights into the genomic diversity of the genus Nitrospira and provides a foundation for future comparative genomic studies that will generate a better understanding of the nitrification process.}, }
@article {pmid30498480, year = {2018}, author = {Zäncker, B and Cunliffe, M and Engel, A}, title = {Bacterial Community Composition in the Sea Surface Microlayer Off the Peruvian Coast.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2699}, pmid = {30498480}, issn = {1664-302X}, abstract = {The sea surface microlayer (SML) is located at the air-sea interface, with microorganisms and organic matter in the SML influencing air-sea exchange processes. Yet understanding of the SML bacterial (bacterioneuston) community composition and assembly remains limited. Availability of organic matter, UV radiation and wind speed have previously been suggested to influence the community composition of bacterioneuston. Another mechanism potentially controlling bacterioneuston dynamics is bacterioplankton attached to gel-like particles that ascend through the water column into the SML. We analyzed the bacterial community composition, Transparent Exopolymer Particles (TEP) abundance and nutrient concentrations in the surface waters of the Peruvian upwelling region. The bacterioneuston and bacterioplankton communities were similar, suggesting a close spatial coupling. Four Bacteroidetes families were significantly enriched in the SML, two of them, the Flavobacteriaceae and Cryomorphaceae, were found to comprise the majority of SML-enriched operational taxonomic units (OTUs). The enrichment of these families was controlled by a variety of environmental factors. The SML-enriched bacterial families were negatively correlated with water temperature and wind speed in the SML and positively correlated with nutrient concentrations, salinity and TEP in the underlying water (ULW). The correlations with nutrient concentrations and salinity suggest that the enriched bacterial families were more abundant at the upwelling stations.}, }
@article {pmid30497363, year = {2018}, author = {Sperlea, T and Füser, S and Boenigk, J and Heider, D}, title = {SEDE-GPS: socio-economic data enrichment based on GPS information.}, journal = {BMC bioinformatics}, volume = {19}, number = {Suppl 15}, pages = {440}, pmid = {30497363}, issn = {1471-2105}, mesh = {Algorithms ; Biodiversity ; *Geographic Information Systems ; Lakes ; Machine Learning ; Microbiota ; Socioeconomic Factors ; }, abstract = {BACKGROUND: Microbes are essentail components of all ecosystems because they drive many biochemical processes and act as primary producers. In freshwater ecosystems, the biodiversity in and the composition of microbial communities can be used as indicators for environmental quality. Recently, some environmental features have been identified that influence microbial ecosystems. However, the impact of human action on lake microbiomes is not well understood. This is, in part, due to the fact that environmental data is, albeit theoretically accessible, not easily available.<br><br>RESULTS: In this work, we present SEDE-GPS, a tool that gathers data that are relevant to the environment of an user-provided GPS coordinate. To this end, it accesses a list of public and corporate databases and aggregates the information in a single file, which can be used for further analysis. To showcase the use of SEDE-GPS, we enriched a lake microbial ecology sequencing dataset with around 18,000 socio-economic, climate, and geographic features. The sources of SEDE-GPS are public databases such as Eurostat, the Climate Data Center, and OpenStreetMap, as well as corporate sources such as Twitter. Using machine learning and feature selection methods, we were able to identify features in the data provided by SEDE-GPS that can be used to predict lake microbiome alpha diversity.<br><br>CONCLUSION: The results presented in this study show that SEDE-GPS is a handy and easy-to-use tool for comprehensive data enrichment for studies of ecology and other processes that are affected by environmental features. Furthermore, we present lists of environmental, socio-economic, and climate features that are predictive for microbial biodiversity in lake ecosystems. These lists indicate that human action has a major impact on lake microbiomes. SEDE-GPS and its source code is available for download at http://SEDE-GPS.heiderlab.de.}, }
@article {pmid30496195, year = {2018}, author = {Calderoli, PA and Espínola, FJ and Dionisi, HM and Gil, MN and Jansson, JK and Lozada, M}, title = {Predominance and high diversity of genes associated to denitrification in metagenomes of subantarctic coastal sediments exposed to urban pollution.}, journal = {PloS one}, volume = {13}, number = {11}, pages = {e0207606}, doi = {10.1371/journal.pone.0207606}, pmid = {30496195}, issn = {1932-6203}, mesh = {Archaea/*genetics/isolation &amp; purification ; Archaeal Proteins/classification/genetics/metabolism ; Argentina ; Bacteria/*genetics/isolation &amp; purification ; Bacterial Proteins/classification/genetics/metabolism ; Bays ; Cluster Analysis ; DNA/chemistry/isolation &amp; purification/metabolism ; Denitrification/*genetics ; *Genetic Variation ; Geologic Sediments/*microbiology ; *Metagenomics ; Nitrous Oxide/metabolism ; Phylogeny ; Sequence Analysis, DNA ; }, abstract = {The aim of this work was to characterize the microbial nitrogen cycling potential in sediments from Ushuaia Bay, a subantarctic environment that has suffered a recent explosive demographic growth. Subtidal sediment samples were retrieved in triplicate from two urban points in the Bay, and analyzed through metagenomic shotgun sequencing. Sequences assigned to genes related to nitrification, nitrate reduction and denitrification were predominant in this environment with respect to metagenomes from other environments, including other marine sediments. The nosZ gene, responsible for nitrous oxide transformation into di-nitrogen, presented a high diversity. The majority of NosZ sequences were classified as Clade II (atypical) variants affiliated to different bacterial lineages such as Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, Verrucomicrobia, as well as to Archaea. The analysis of a fosmid metagenomic library from the same site showed that the genomic context of atypical variants was variable, and was accompanied by distinct regulatory elements, suggesting the evolution of differential ecophysiological roles. This work increases our understanding of the microbial ecology of nitrogen transformations in cold coastal environments and provides evidence of an enhanced denitrification potential in impacted sediment microbial communities. In addition, it highlights the role of yet overlooked populations in the mitigation of environmentally harmful forms of nitrogen.}, }
@article {pmid30487782, year = {2018}, author = {Vadstein, O and Attramadal, KJK and Bakke, I and Olsen, Y}, title = {K-Selection as Microbial Community Management Strategy: A Method for Improved Viability of Larvae in Aquaculture.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2730}, pmid = {30487782}, issn = {1664-302X}, abstract = {Aquaculture has the potential to become a major food supplier in a world with an increasing human population, and increased consumption of fish will likely have positive health implications. For marine aquaculture, the production of high quality juveniles is a bottleneck. Survival until the juvenile stage is typically as low as 10-15% for many species, which indicates suboptimal rearing conditions. Substantial evidence indicates that the poor performance and viability of larvae is largely due to detrimental larvae-microbiota interactions. This emphasises the need for microbial management strategies in the cultivation of marine fish larvae. Disinfection and probiotics are the most studied microbial management methods so far. However, most studies on these methods overlooked the role of mutualistic relationships between microbes and hosts, and have not proposed or examined methods steering toward such relationships. Based on ecological theory and a number of experiments, we find support for the hypothesis that current practise in aquaculture generally selects for r-strategic, opportunistic microbes, which results in detrimental host-microbiota interactions. Thus, the challenge is to develop technology and methods for microbial management at the ecosystem level that creates a K-selected microbial community, and by this mean select against r-strategic opportunists. Here we summarise experiments done during 25 years and with marine larvae of five different species showing that: (1) K-selection strategies result in different water microbiota with less opportunists, (2) this influences the microbiota of the fish larvae, and (3) the larvae cultivated in water inhabited by a K-selected microbiota perform better. Improved performance of larvae includes improved appetite, earlier onset of and faster growth, increased survival, and increased robustness to stress. K-selection as a method for management of the microbial community is a robust approach that allows steering of host-microbiota interactions in larviculture toward mutualism. It could also be applicable for young stages of other domesticated animals. Our review illustrates that a change from a &quot;beat-them&quot; to a &quot;join-them&quot; strategy for microbial management in larval rearing can lead to a more sustainable aquaculture industry.}, }
@article {pmid30483839, year = {2018}, author = {Zakharenko, AS and Galachyants, YP and Morozov, IV and Shubenkova, OV and Morozov, AA and Ivanov, VG and Pimenov, NV and Krasnopeev, AY and Zemskaya, TI}, title = {Bacterial Communities in Areas of Oil and Methane Seeps in Pelagic of Lake Baikal.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1299-5}, pmid = {30483839}, issn = {1432-184X}, support = {17-29-05040//ofi-m RFBR/ ; 0345-2016-0007//State Task for Limnological Institute SB RAS/ ; 18-34-00442//a-mol RFBR/ ; }, abstract = {We have assessed the diversity of bacteria near oil-methane (area I) and methane (area II) seeps in the pelagic zone of Lake Baikal using massive parallel sequencing of 16S rRNA, pmoA, and mxaF gene fragments amplified from total DNA. At depths from the surface to 100 m, sequences belonging to Cyanobacteria dominated. In the communities to a depth of 200 m of the studied areas, Proteobacteria dominated the deeper layers of the water column. Alphaproteobacteria sequences were predominant in the community near the oil-methane seep, while the community near the methane seep was characterized by the prevalence of Alpha- and Gammaproteobacteria. Among representatives of these classes, type I methanotrophs prevailed in the 16S rRNA gene libraries from the near-bottom area, and type II methanotrophs were detected in minor quantities at different depths. In the analysis of the libraries of the pmoA and mxaF functional genes, we observed the different taxonomic composition of methanotrophic bacteria in the surface and deep layers of the water column. All pmoA sequences from area I were type II methanotrophs and were detected at a depth of 300 m, while sequences of type I methanotrophs were the most abundant in deep layers of the water column of area II. All mxaF gene sequences belonged to Methylobacterium representatives. Based on comparative analyses of 16S rRNA, pmoA, and mxaF gene fragment libraries, we suggest that there must be a wider spectrum of functional genes facilitating methane oxidation that were not detected with the primers used.}, }
@article {pmid30482830, year = {2018}, author = {Espinoza, JL and Harkins, DM and Torralba, M and Gomez, A and Highlander, SK and Jones, MB and Leong, P and Saffery, R and Bockmann, M and Kuelbs, C and Inman, JM and Hughes, T and Craig, JM and Nelson, KE and Dupont, CL}, title = {Supragingival Plaque Microbiome Ecology and Functional Potential in the Context of Health and Disease.}, journal = {mBio}, volume = {9}, number = {6}, pages = {}, pmid = {30482830}, issn = {2150-7511}, support = {R01 DE019665/DE/NIDCR NIH HHS/United States ; R01 GM120624/GM/NIGMS NIH HHS/United States ; }, mesh = {Australia ; Bacteria/*classification/*genetics ; Child ; Child, Preschool ; Dental Caries/*microbiology ; Dental Plaque/*microbiology ; Humans ; Metabolic Networks and Pathways/genetics ; Metagenomics ; *Microbiota ; Sequence Analysis, DNA ; }, abstract = {To address the question of how microbial diversity and function in the oral cavities of children relates to caries diagnosis, we surveyed the supragingival plaque biofilm microbiome in 44 juvenile twin pairs. Using shotgun sequencing, we constructed a genome encyclopedia describing the core supragingival plaque microbiome. Caries phenotypes contained statistically significant enrichments in specific genome abundances and distinct community composition profiles, including strain-level changes. Metabolic pathways that are statistically associated with caries include several sugar-associated phosphotransferase systems, antimicrobial resistance, and metal transport. Numerous closely related previously uncharacterized microbes had substantial variation in central metabolism, including the loss of biosynthetic pathways resulting in auxotrophy, changing the ecological role. We also describe the first complete Gracilibacteria genomes from the human microbiome. Caries is a microbial community metabolic disorder that cannot be described by a single etiology, and our results provide the information needed for next-generation diagnostic tools and therapeutics for caries.IMPORTANCE Oral health has substantial economic importance, with over $100 billion spent on dental care in the United States annually. The microbiome plays a critical role in oral health, yet remains poorly classified. To address the question of how microbial diversity and function in the oral cavities of children relate to caries diagnosis, we surveyed the supragingival plaque biofilm microbiome in 44 juvenile twin pairs. Using shotgun sequencing, we constructed a genome encyclopedia describing the core supragingival plaque microbiome. This unveiled several new previously uncharacterized but ubiquitous microbial lineages in the oral microbiome. Caries is a microbial community metabolic disorder that cannot be described by a single etiology, and our results provide the information needed for next-generation diagnostic tools and therapeutics for caries.}, }
@article {pmid30481288, year = {2019}, author = {Khan, MAW and Bohannan, BJM and Nüsslein, K and Tiedje, JM and Tringe, SG and Parlade, E and Barberán, A and Rodrigues, JLM}, title = {Deforestation impacts network co-occurrence patterns of microbial communities in Amazon soils.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {2}, pages = {}, doi = {10.1093/femsec/fiy230}, pmid = {30481288}, issn = {1574-6941}, abstract = {Co-occurrence networks allow for the identification of potential associations among species, which may be important for understanding community assembly and ecosystem functions. We employed this strategy to examine prokaryotic co-occurrence patterns in the Amazon soils and the response of these patterns to land use change to pasture, with the hypothesis that altered microbial composition due to deforestation will mirror the co-occurrence patterns across prokaryotic taxa. In this study, we calculated Spearman correlations between operational taxonomic units (OTUs) as determined by 16S rRNA gene sequencing, and only robust correlations were considered for network construction (-0.80 ≥ P ≥ 0.80, adjusted P < 0.01). The constructed network represents distinct forest and pasture components, with altered compositional and topological features. A comparative analysis between two representative modules of these contrasting ecosystems revealed novel information regarding changes to metabolic pathways related to nitrogen cycling. Our results showed that soil physicochemical properties such as temperature, C/N and H++Al3+ had a significant impact on prokaryotic communities, with alterations to network topologies. Taken together, changes in co-occurrence patterns and physicochemical properties may contribute to ecosystem processes including nitrification and denitrification, two important biogeochemical processes occurring in tropical forest systems.}, }
@article {pmid30479328, year = {2018}, author = {de Bruijn, I and Verhoeven, KJF}, title = {Cross-species interference of gene expression.}, journal = {Nature communications}, volume = {9}, number = {1}, pages = {5019}, pmid = {30479328}, issn = {2041-1723}, mesh = {Epigenesis, Genetic ; *Gene Expression Regulation ; RNA/genetics ; Species Specificity ; }, abstract = {Microbes can contribute to protection of animals and plants against diseases. A recent study reveals a mechanism by which a bacterium controls fungal infection in wheat, involving secretion of a metabolite that affects histone acetyltransferase activity of a plant pathogenic fungus.}, }
@article {pmid30478730, year = {2019}, author = {Dhaulaniya, AS and Balan, B and Kumar, M and Agrawal, PK and Singh, DK}, title = {Cold survival strategies for bacteria, recent advancement and potential industrial applications.}, journal = {Archives of microbiology}, volume = {201}, number = {1}, pages = {1-16}, doi = {10.1007/s00203-018-1602-3}, pmid = {30478730}, issn = {1432-072X}, support = {NASF/CA-6030/2017-18//National Agriculture Science Fund/ ; }, mesh = {Adaptation, Physiological/*physiology ; Bacteria/*enzymology/*metabolism ; Biodegradation, Environmental ; *Cold Temperature ; Ecosystem ; Food Microbiology ; Humans ; Hydrocarbons/metabolism ; }, abstract = {Microorganisms have evolved themselves to thrive under various extreme environmental conditions such as extremely high or low temperature, alkalinity, and salinity. These microorganisms adapted several metabolic processes to survive and reproduce efficiently under such extreme environments. As the major proportion of earth is covered with the cold environment and is exploited by human beings, these sites are not pristine anymore. Human interventions are a great reason for disturbing the natural biogeochemical cycles in these regions. The survival strategies of these organisms have shown great potential for helping us to restore these pristine sites and the use of isolated cold-adapted enzymes from these organisms has also revolutionized various industrial products. This review gives you the insight of psychrophilic enzyme adaptations and their industrial applications.}, }
@article {pmid30478232, year = {2019}, author = {Liang, C and Huang, Y and Wang, H}, title = {pahE, a Functional Marker Gene for Polycyclic Aromatic Hydrocarbon-Degrading Bacteria.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {3}, pages = {}, doi = {10.1128/AEM.02399-18}, pmid = {30478232}, issn = {1098-5336}, abstract = {The characterization of native polycyclic aromatic hydrocarbon (PAH)-degrading bacteria is significant for understanding the PAH degradation process in the natural environment and developing effective remediation technologies. Most previous investigations of PAH-degrading bacteria in environmental samples employ pahAc, which encodes the α-subunit of PAH ring-hydroxylating dioxygenase, as a functional marker gene. However, the poor phylogenetic resolution and nonspecificity of pahAc result in a misestimation of PAH-degrading bacteria. Here, we propose a PAH hydratase-aldolase-encoding gene, pahE, as a superior biomarker for PAH-degrading bacteria. Comparative phylogenetic analysis of the key enzymes involved in the upper pathway of PAH degradation indicated that pahE evolved dependently from a common ancestor. A phylogenetic tree constructed based on PahE is largely congruent with PahAc-based phylogenies, except for the dispersion of several clades of other non-PAH-degrading aromatic hydrocarbon dioxygenases present in the PahAc tree. Analysis of pure strains by PCR confirmed that pahE can specifically distinguish PAH-degrading bacteria, while pahAc cannot. Illumina sequencing of pahE and pahAc amplicons showed more genotypes and higher specificity and resolution for pahE Novel reads were also discovered among the pahE amplicons, suggesting the presence of novel PAH-degrading populations. These results suggest that pahE is a more powerful biomarker for exploring the ecological role and degradation potential of PAH-degrading bacteria in ecosystems, which is significant to the bioremediation of PAH pollution and environmental microbial ecology.IMPORTANCE PAH contamination has become a worldwide environmental issue because of the potential toxic effects on natural ecosystems and human health. Biotransformation and biodegradation are considered the main natural elimination forms of PAHs from contaminated sites. Therefore, the knowledge of the degradation potential of the microbial community in contaminated sites is crucial for PAH pollution bioremediation. However, the nonspecificity of pahAc as a functional marker of PAH-degrading bacteria has resulted neither in a reliable prediction of PAH degradation potential nor an accurate assessment of degradation. Here, we introduced pahE encoding the PAH hydratase-aldolase as a new and better functional marker gene of PAH-degrading bacteria. This study provides a powerful molecular tool to more effectively explore the ecological role and degradation potential of PAH-degrading bacteria in ecosystems, which is significant to the bioremediation of PAH pollution.}, }
@article {pmid30477264, year = {2018}, author = {Almendras, K and García, J and Carú, M and Orlando, J}, title = {Nitrogen-Fixing Bacteria Associated with Peltigera Cyanolichens and Cladonia Chlorolichens.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {12}, pages = {}, doi = {10.3390/molecules23123077}, pmid = {30477264}, issn = {1420-3049}, support = {11100381 and 1181510//Fondo Nacional de Desarrollo Científico y Tecnológico/ ; }, mesh = {Analysis of Variance ; Ascomycota/classification/*physiology ; Molecular Typing/methods ; Nitrogen-Fixing Bacteria/*physiology ; RNA, Ribosomal, 28S/genetics ; Symbiosis ; }, abstract = {Lichens have been extensively studied and described; however, recent evidence suggests that members of the bacterial community associated with them could contribute new functions to the symbiotic interaction. In this work, we compare the nitrogen-fixing guild associated with bipartite terricolous lichens with different types of photobiont: Peltigera cyanolichens and Cladonia chlorolichens. Since cyanobacteria contribute nitrogen to the symbiosis, we propose that chlorolichens have more diverse bacteria with the ability to fix nitrogen compared to cyanolichens. In addition, since part of these bacteria could be recruited from the substrate where lichens grow, we propose that thalli and substrates share some bacteria in common. The structure of the nitrogen-fixing guild in the lichen and substrate bacterial communities of both lichens was determined by terminal restriction fragment length polymorphism (TRFLP) of the nifH gene. Multivariate analyses showed that the nitrogen-fixing bacteria associated with both types of lichen were distinguishable from those present in their substrates. Likewise, the structure of the nitrogen-fixing bacteria present in the cyanolichens was different from that of chlorolichens. Finally, the diversity of this bacterial guild calculated using the Shannon index confirms the hypothesis that chlorolichens have a higher diversity of nitrogen-fixing bacteria than cyanolichens.}, }
@article {pmid30476032, year = {2019}, author = {Nierychlo, M and Milobedzka, A and Petriglieri, F and McIlroy, B and Nielsen, PH and McIlroy, SJ}, title = {The morphology and metabolic potential of the Chloroflexi in full-scale activated sludge wastewater treatment plants.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {2}, pages = {}, doi = {10.1093/femsec/fiy228}, pmid = {30476032}, issn = {1574-6941}, abstract = {Filamentous bacteria belonging to the phylum Chloroflexi have received considerable attention in wastewater treatment systems for their suggested role in the operational problem of impaired sludge settleability known as bulking. Their consistently high abundance in full-scale systems, even in the absence of bulking, indicates that they make a substantial contribution to the nutrient transformations during wastewater treatment. In this study, extensive 16S rRNA amplicon surveys of Danish wastewater treatment plants (WWTPs) with nutrient removal were screened to identify numerically important Chloroflexi genera. Fluorescence in situ hybridization probes were designed for their in situ characterization. All abundant Chloroflexi phylotypes were putatively identified as facultative anaerobic chemoorganotrophs involved in sugar fermentation. They were all filamentous but differed in their morphology and spatial arrangement. 'Candidatus Villigracilis' was predominantly located within the activated sludge flocs, where they possibly have structural importance, and their abundance was relatively stable. Conversely, the abundance of 'Candidatus Amarolinea' was highly dynamic, relative to other genera, sometimes reaching abundances in excess of 30% of the biovolume, suggesting their likely role in bulking episodes. This study gives an important insight into the role of Chloroflexi in WWTPs, thus contributing to the broader goal of understanding the ecology of these biotechnologically important systems.}, }
@article {pmid30474807, year = {2019}, author = {Wu, H and Chen, H and Jin, C and Tang, C and Zhang, Y}, title = {The chirality of imazethapyr herbicide selectively affects the bacterial community in soybean field soil.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {3}, pages = {2531-2546}, doi = {10.1007/s11356-018-3736-x}, pmid = {30474807}, issn = {1614-7499}, support = {41071314//National Natural Science Foundation of China/ ; }, mesh = {Bacteria/classification/*drug effects/genetics/isolation &amp; purification ; China ; Herbicides/chemistry/*pharmacology ; Nicotinic Acids/chemistry/*pharmacology ; RNA, Ribosomal, 16S/genetics ; Soil/chemistry ; Soil Microbiology ; Soil Pollutants/chemistry/pharmacology ; Soybeans/*growth &amp; development ; Stereoisomerism ; }, abstract = {The chiral herbicide imazethapyr (IM) is frequently used to control weeds in soybean fields in northeast China. However, the impact of IM enantiomers on microbial communities in soil is still unknown. Genetic markers (16S rRNA V3-V4 regions) were used to characterize and evaluate the variation of the bacterial communities potentially effected by IM enantiomers. Globally, the bacterial community structure based on the OTU profiles in (-)-R-IM-treated soils was significantly different from those in (+)-S-IM-treated soils, and the differences were enlarged with the treatment dose increasing. Interestingly, the Rhizobiaceae family and several other beneficial bacteria, including Bradyrhizobium, Methylobacterium, and Paenibacillus, were strongly enriched in (-)-R-IM treatment compared to (+)-S-IM treatment. In contrast, the pathogenic bacteria, including Erwinia, Pseudomonas, Burkholderia, Streptomyces, and Agrobacterium, were suppressed in the presence of (-)-R-IM compared to (+)-S-IM. Furthermore, we also observed that the bacterial community structure in (-)-R-IM-treated soils was more quickly restored to its original state compared with those in (+)-S-IM-treated soils. These findings unveil a new role of chiral herbicide in the development of soil microbial ecology and provide theoretical support for the application of low-persistence, high-efficiency, and eco-friendly optical rotatory (-)-R-IM.}, }
@article {pmid30474731, year = {2018}, author = {Hosseinzadeh, S and Shams-Bakhsh, M and Mann, M and Fattah-Hosseini, S and Bagheri, A and Mehrabadi, M and Heck, M}, title = {Distribution and Variation of Bacterial Endosymbiont and &quot;Candidatus Liberibacter asiaticus&quot; Titer in the Huanglongbing Insect Vector, Diaphorina citri Kuwayama.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1290-1}, pmid = {30474731}, issn = {1432-184X}, support = {5300-163//California Citrus Research Board/ ; 2016-70016-24779//National Institute of Food and Agriculture/ ; 8062-22410-006-00-D//Agricultural Research Service/ ; }, abstract = {The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an economic insect pest in most citrus-growing regions and the vector of 'Candidatus Liberibacter asiaticus' (CLas), one of at least three known bacteria associated with Huanglongbing (HLB or citrus greening disease). D. citri harbors bacterial endosymbionts, including Wolbachia pipientis (strain Wolbachia wDi), 'Candidatus Carsonella ruddii,' and 'Candidatus Profftella armatura.' Many important functions of these bacteria can be inferred from their genome sequences, but their interactions with each other, CLas, and their D. citri host are poorly understood. In the present study, the titers of the endosymbionts in different tissues, in each sex, and in insects reared on healthy citrus (referred to as unexposed) and CLas-infected citrus (referred to as CLas-exposed) D. citri were investigated using real-time, quantitative PCR (qPCR) using two different quantitative approaches. Wolbachia and CLas were detected in all insect tissues. The titer of Wolbachia was higher in heads of CLas-exposed males as compared to unexposed males. In males and females, Wolbachia titer was highest in the Malpighian tubules. The highest titer of CLas was observed in the gut. Profftella and Carsonella titers were significantly reduced in the bacteriome of CLas-exposed males compared with that of unexposed males, but this effect was not observed in females. In ovaries of CLas-exposed females, the Profftella and Carsonella titers were increased as compared to non-exposed females. CLas appeared to influence the overall levels of the symbionts but did not drastically perturb the overall microbial community structure. In all the assessed tissues, CLas titer in males was significantly higher than that of females using absolute quantification. These data provide a better understanding of multi-trophic interactions regulating symbiont dynamics in the HLB pathosystem.}, }
@article {pmid30474730, year = {2018}, author = {Lima, BP and Hu, LI and Vreeman, GW and Weibel, DB and Lux, R}, title = {The Oral Bacterium Fusobacterium nucleatum Binds Staphylococcus aureus and Alters Expression of the Staphylococcal Accessory Regulator sarA.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1291-0}, pmid = {30474730}, issn = {1432-184X}, support = {DE021108//National Institute of Dental and Craniofacial Research/ ; DMR-1121288//National Science Foundation/ ; }, abstract = {Staphylococcus aureus, an opportunistic pathogen member of the nasal and skin microbiota, can also be found in human oral samples and has been linked to infectious diseases of the oral cavity. As the nasal and oral cavities are anatomically connected, it is currently unclear whether S. aureus can colonize the oral cavity and become part of the oral microbiota, or if its presence in the oral cavity is simply transient. To start addressing this question, we assessed S. aureus ability to directly bind selected members of the oral microbiota as well as its ability to integrate into a human-derived complex oral microbial community in vitro. Our data show that S. aureus forms aggregates with Fusobacterium nucleatum and Porphyromonas gingivalis and that it can incorporate into the human-derived in vitro oral community. Further analysis of the F. nucleatum-S. aureus interaction revealed that the outer-membrane adhesin RadD is partially involved in aggregate formation and that the RadD-mediated interaction leads to an increase in expression of the staphylococcal global regulator gene sarA. Our findings lend support to the notion that S. aureus can become part of the complex microbiota of the human mouth, which could serve as a reservoir for S. aureus. Furthermore, direct interaction with key members of the oral microbiota could affect S. aureus pathogenicity contributing to the development of several S. aureus associated oral infections.}, }
@article {pmid30474350, year = {2019}, author = {Cox, TL and Gan, HM and Moreau, JW}, title = {Seawater recirculation through subducting sediments sustains a deeply buried population of sulfate-reducing bacteria.}, journal = {Geobiology}, volume = {17}, number = {2}, pages = {172-184}, doi = {10.1111/gbi.12324}, pmid = {30474350}, issn = {1472-4669}, mesh = {Bacteria/classification/*metabolism ; Geologic Sediments/*microbiology ; Oxidation-Reduction ; Pacific Ocean ; Phylogeny ; Seawater/*analysis ; Sequence Analysis, Protein ; Sulfates/*metabolism ; }, abstract = {Subseafloor sulfate concentrations typically decrease with depth as this electron acceptor is consumed by respiring microorganisms. However, studies show that seawater can flow through hydraulically conductive basalt to deliver sulfate upwards into deeply buried overlying sediments. Our previous work on IODP Site C0012A (Nankai Trough, Japan) revealed that recirculation of sulfate through the subducting Philippine Sea Plate stimulated microbial activity near the sediment-basement interface (SBI). Here, we describe the microbial ecology, phylogeny, and energetic requirements of population of aero-tolerant sulfate-reducing bacteria in the deep subseafloor. We identified dissimilatory sulfite reductase gene (dsr) sequences 93% related to oxygen-tolerant Desulfovibrionales species across all reaction zones while no SRB were detected in drilling fluid control samples. Pore fluid chemistry revealed low concentrations of methane (<0.25 mM), while hydrogen levels were consistent with active bacterial sulfate reduction (0.51-1.52 nM). Solid phase total organic carbon (TOC) was also considerably low in these subseafloor sediments. Our results reveal the phylogenetic diversity, potential function, and physiological tolerance of a community of sulfate-reducing bacteria living at ~480 m below subducting seafloor.}, }
@article {pmid30471620, year = {2018}, author = {Gutiérrez, S and Zwart, MP}, title = {Population bottlenecks in multicomponent viruses: first forays into the uncharted territory of genome-formula drift.}, journal = {Current opinion in virology}, volume = {33}, number = {}, pages = {184-190}, doi = {10.1016/j.coviro.2018.09.001}, pmid = {30471620}, issn = {1879-6265}, abstract = {Multicomponent viral systems face specific challenges when enduring population bottlenecks. These systems can lose coding information due to the lack of co-encapsidation of all the genetic information, at least in a proportion of the capsids in a population. Moreover, bottlenecks can also impact one of the main potential advantages of multicomponent systems: the regulation of gene expression through changes in gene copy frequencies at the population level. How these systems cope with population bottlenecks is far from being clear. Here, two non-exclusive scenarios are described. In the first scenario, population bottlenecks during host infection allow for the isolation of within-host populations with different gene frequencies, leaving the door opened for the selection of populations with adaptive gene frequencies. The second scenario postulates that viruses could influence bottleneck size, at least at certain steps of their life cycle, to limit random changes in gene frequencies. Examples of viral mechanism impacting bottleneck size at cell infection are available and, intriguingly, they can lead to either increases or reductions in bottleneck size. This situation opens the way for putative trade-offs on both gene frequencies and bottleneck sizes that could differ among multicomponent systems.}, }
@article {pmid30470844, year = {2019}, author = {Lizoňová, Z and Zhai, M and Bojková, J and Horsák, M}, title = {Small-scale Variation of Testate Amoeba Assemblages: the Effect of Site Heterogeneity and Empty Shell Inclusion.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1014-1024}, doi = {10.1007/s00248-018-1292-z}, pmid = {30470844}, issn = {1432-184X}, support = {P505/16-03881S//Grantová Agentura České Republiky/ ; }, mesh = {Bryophyta/growth &amp; development ; Czech Republic ; Lobosea/classification/*physiology ; *Microbiota ; Soil/*chemistry ; Wetlands ; }, abstract = {Studies on testate amoeba species distribution at small scales (i.e., single peatland sites) are rare and mostly focus on bogs or mineral-poor Sphagnum fens, leaving spatial patterns within mineral-rich fens completely unexplored. In this study, two mineral-rich fen sites of contrasting groundwater chemistry and moss layer composition were selected for the analysis of testate amoeba compositional variance within a single site. At each study site, samples from 20 randomly chosen moss-dominated plots were collected with several environmental variables being measured at each sampling spot. We also distinguished between empty shells and living individuals to evaluate the effect of empty shell inclusion on recorded species distribution. At the heterogeneous-rich Sphagnum-fen, a clear composition turnover in testate amoebae between Sphagnum-dominated and brown moss-dominated samples was closely related to water pH, temperature and redox potential. We also found notable species composition variance within the homogeneous calcareous fen, yet it was not as high as for the former site and the likely drivers of community assembly remained unidentified. The exclusion of empty shells provided more accurate data on species distribution as well as their relationship with some environmental variables, particularly moisture. Small-scale variability in species composition of communities seems to be a worthwhile aspect in testate amoeba research and should be considered in future sampling strategies along with a possible empty shell bias for more precise understanding of testate amoeba ecology and paleoecology.}, }
@article {pmid30469475, year = {2018}, author = {Chi, H and Yang, L and Yang, W and Li, Y and Chen, Z and Huang, L and Chao, Y and Qiu, R and Wang, S}, title = {Variation of the Bacterial Community in the Rhizoplane Iron Plaque of the Wetland Plant Typha latifolia.}, journal = {International journal of environmental research and public health}, volume = {15}, number = {12}, pages = {}, doi = {10.3390/ijerph15122610}, pmid = {30469475}, issn = {1660-4601}, mesh = {Bacteria/*isolation &amp; purification ; Environmental Monitoring ; Iron/*chemistry ; Plant Roots/*chemistry/*microbiology ; *Rhizosphere ; Soil Microbiology ; Soil Pollutants/*chemistry ; Typhaceae/*chemistry ; Wetlands ; }, abstract = {The survival of wetland plants in iron, sulfur and heavy metals-rich mine tailing ponds has been commonly attributed to the iron plaque (IP) on the root surface that acts as a protective barrier. However, the contribution of bacteria potentially regulates the iron-sulfur cycle and heavy metal exclusion at the root surface has not been studied in depth, particularly from a microbial ecology perspective. In this study, a pot experiment using Typha latifolia, a typical wetland plant, in non-polluted soil (NP) and tailing soil (T) was conducted. Samples from four zones, comprising non-rhizosphere soil (NR), rhizosphere soil (R) and internal (I) and external (E) layers of iron plaque, were collected from the NP and T and analyzed by 16S rRNA sequencing. Simpson index of the genus level showed greater diversities of bacterial community in the NP and its I zone is the most important part of the rhizosphere. PICRUSt predicted that the I zones in both NP and T harbored most of the functional genes. Specifically, functional genes related to sulfur relay and metabolism occurred more in the I zone in the T, whereas those related to iron acquisition and carbon and nitrogen circulation occurred more in the I zone in the NP. Analysis of dominant bacterial communities at genus level showed highest abundance of heavy metal resistant genus Burkholderia in the E zones in both soils, indicating that heavy metal resistance of Typha latifolia driven by Burkholderia mainly occurred at the external layer of IP. Moreover, many bacterial genera, such as Acidithiobacillus, Ferritrophicum, Thiomonas, Metallibacterium and Sideroxydans, involved in iron and sulfur metabolisms were found in the T and most showed higher abundance in the I zone than in the other zones. This work, as the first endeavor to separate the iron plaque into external and internal layers and investigate the variations of the bacterial communities therein, can provide an insight for further understanding the survival strategy of wetland plants, e.g., Typha latifolia, in extreme environment.}, }
@article {pmid30467715, year = {2019}, author = {Lemmel, F and Maunoury-Danger, F and Fanesi, A and Leyval, C and Cébron, A}, title = {Soil Properties and Multi-Pollution Affect Taxonomic and Functional Bacterial Diversity in a Range of French Soils Displaying an Anthropisation Gradient.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {993-1013}, doi = {10.1007/s00248-018-1297-7}, pmid = {30467715}, issn = {1432-184X}, support = {ANR-13-JSV7-000701//Agence Nationale de la Recherche/ ; EC2CO- Biohefect/Ecodyn//Dril/MicrobiEen (EcobioS project)//Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique/ ; traitMic project//OSU-Otelo/ ; }, mesh = {Bacteria/*classification/drug effects ; *Carbon Cycle ; DNA, Bacterial/analysis ; France ; Industrial Waste ; *Microbiota ; RNA, Ribosomal, 16S/analysis ; Soil/*chemistry ; *Soil Microbiology ; Soil Pollutants/*analysis ; }, abstract = {The intensive industrial activities of the twentieth century have left behind highly contaminated wasteland soils. It is well known that soil parameters and the presence of pollutants shape microbial communities. But in such industrial waste sites, the soil multi-contamination with organic (polycyclic aromatic hydrocarbons, PAH) and metallic (Zn, Pb, Cd) pollutants and long-term exposure may induce a selection pressure on microbial communities that may modify soil functioning. The aim of our study was to evaluate the impact of long-term multi-contamination and soil characteristics on bacterial taxonomic and functional diversity as related to the carbon cycle. We worked on 10 soils from northeast of France distributed into three groups (low anthropised controls, slag heaps, and settling ponds) based on their physico-chemical properties (texture, C, N) and pollution level. We assessed bacterial taxonomic diversity by 16S rDNA Illumina sequencing, and functional diversity using Biolog® and MicroResp™ microtiter plate tools. Although taxonomic diversity at the phylum level was not different among the soil groups, many operational taxonomic units were influenced by metal or PAH pollution, and by soil texture and total nitrogen content. Functional diversity was not influenced by PAH contamination while metal pollution selected microbial communities with reduced metabolic functional diversity but more tolerant to zinc. Limited microbial utilisation of carbon substrates in metal-polluted soils was mainly due to the nitrogen content. Based on these two observations, we hypothesised that reduced microbial activity and lower carbon cycle-related functional diversity may have contributed to the accumulation of organic matter in the soils that exhibited the highest levels of metal pollution.}, }
@article {pmid30467714, year = {2018}, author = {Ellison, S and Rovito, S and Parra-Olea, G and Vásquez-Almazán, C and Flechas, SV and Bi, K and Vredenburg, VT}, title = {The Influence of Habitat and Phylogeny on the Skin Microbiome of Amphibians in Guatemala and Mexico.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1288-8}, pmid = {30467714}, issn = {1432-184X}, support = {IOS-1258133//National Science Foundation/ ; 1633948//National Science Foundation/ ; DEB-1026396//National Science Foundation/ ; ICER-1633948//National Science Foundation/ ; CN-13-614//University of California Institute for Mexico and the United States/ ; }, abstract = {Microbial symbionts are increasingly recognized as playing a critical role in organismal health across a wide range of hosts. Amphibians are unique hosts in that their skin helps to regulate the exchange of water, ions, and gases, and it plays an active role in defense against pathogens through the synthesis of anti-microbial peptides. The microbiome of amphibian skin includes a diverse community of bacteria known to defend against pathogens, including the global pandemic lineage of Batrachochytrium dendrobatidis associated with mass amphibian die-offs. The relative influence of host phylogeny and environment in determining the composition of the amphibian skin microbiome remains poorly understood. We collected skin swabs from montane amphibians in Mexico and Guatemala, focusing on two genera of plethodontid salamanders and one genus of frogs. We used high throughput sequencing to characterize the skin bacterial microbiome and tested the impact of phylogeny and habitat on bacterial diversity. Our results show that phylogenetic history strongly influences the diversity and community structure of the total bacterial microbiome at higher taxonomic levels (between orders), but on lower scales (within genera and species), the effect of habitat predominates. These results add to a growing consensus that habitat exerts a strong effect on microbiome structure and composition, particularly at shallow phylogenetic scales.}, }
@article {pmid30467713, year = {2018}, author = {Ribière, C and Hegarty, C and Stephenson, H and Whelan, P and O'Toole, PW}, title = {Gut and Whole-Body Microbiota of the Honey Bee Separate Thriving and Non-thriving Hives.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1287-9}, pmid = {30467713}, issn = {1432-184X}, support = {SFI/12/RC/2273//Science Foundation Ireland/Ireland ; }, abstract = {The recent worldwide decline of honey bee colonies is a major ecological problem which also threatens pollinated crop production. Several interacting stressors such as environmental pressures and pathogens are suspected. Recently, the gut microbiota has emerged as a critical factor affecting bee health and fitness. We profiled the bacterial communities associated with the gut and whole body of worker bees to assess whether non-thriving colonies could be separated from thriving hives based on their microbial signature. The microbiota of thriving colonies was characterised by higher diversity and higher relative abundance of bacterial taxa involved in sugar degradation that were previously associated with healthy bees (e.g. Commensalibacter sp. and Bartonella apis). In contrast, the microbiota of non-thriving bees was depleted in health-associated species (e.g. Lactobacillus apis), and bacterial taxa associated with disease states (e.g. Gilliamella apicola) and pollen degradation (e.g. G. apicola and Bifidobacterium asteroides) were present in higher abundance compared to thriving colonies. Gut and whole-body microbiota shared a similar dominant core but their comparison showed differences in composition and relative abundance. More differences in taxon relative abundance between gut and whole body were observed in non-thriving bees, suggesting that microbiota associated with other bee organs might also be different. Thus, microbiota profiling could be used as a diagnostic tool in beekeeping practices to predict hive health and guide hive management.}, }
@article {pmid30467310, year = {2018}, author = {Pollock, FJ and McMinds, R and Smith, S and Bourne, DG and Willis, BL and Medina, M and Thurber, RV and Zaneveld, JR}, title = {Coral-associated bacteria demonstrate phylosymbiosis and cophylogeny.}, journal = {Nature communications}, volume = {9}, number = {1}, pages = {4921}, pmid = {30467310}, issn = {2041-1723}, mesh = {Animals ; Anthozoa/classification/*genetics/*microbiology ; Archaea/classification/*genetics ; Australia ; Bacteria/classification/*genetics ; Coral Reefs ; DNA, Mitochondrial/genetics ; Geography ; Microbiota/*genetics ; Phylogeny ; RNA, Ribosomal/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Symbiosis ; }, abstract = {Scleractinian corals' microbial symbionts influence host health, yet how coral microbiomes assembled over evolution is not well understood. We survey bacterial and archaeal communities in phylogenetically diverse Australian corals representing more than 425 million years of diversification. We show that coral microbiomes are anatomically compartmentalized in both modern microbial ecology and evolutionary assembly. Coral mucus, tissue, and skeleton microbiomes differ in microbial community composition, richness, and response to host vs. environmental drivers. We also find evidence of coral-microbe phylosymbiosis, in which coral microbiome composition and richness reflect coral phylogeny. Surprisingly, the coral skeleton represents the most biodiverse coral microbiome, and also shows the strongest evidence of phylosymbiosis. Interactions between bacterial and coral phylogeny significantly influence the abundance of four groups of bacteria-including Endozoicomonas-like bacteria, which divide into host-generalist and host-specific subclades. Together these results trace microbial symbiosis across anatomy during the evolution of a basal animal lineage.}, }
@article {pmid30465731, year = {2018}, author = {Beji, O and Adouani, N and Poncin, S and Hamdi, M and Li, HZ}, title = {Mineral pollutants removal through immobilized microalgae-bacterial flocs in a multitrophic microreactor.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-31}, doi = {10.1080/09593330.2018.1551939}, pmid = {30465731}, issn = {1479-487X}, abstract = {Microalgae-bacterial flocs (MaB-flocs) immobilization technique using polyvinyl alcohol (PVA) crosslinked with sodium alginate represent a novel approach for sustainable pollutants removal. The present work was performed to evaluate the performance of a multitrophic batch reactor at microscale for treating two synthetic wastewater solutions prepared with two different initial Chemical Oxygen Demand (COD): 200 mg.L-1 and 450 mg.L-1, respectively. Three MaB-flocs concentrations were entrapped into PVA-alginate beads: C1 (2%, v/v), C2 (5%, v/v) and C3 (10%, v/v), without O2 supply, during three periods 2, 4 and 6 days of batch incubation. PVA-alginate beads containing the highest concentration C3 of MaB-flocs improved the performance of the microreactor to remove significantly NH4+ and PO43- of about 61% and 82%, respectively, from wastewater more than two other concentrations used. This result confirms that C3 of MaB-flocs displays not only a good potential for nutrients removals but also the highest MaB-flocs morphological progression after 6 days of treatment with the highest COD of 450 mg.L-1. The feasibility of the PVA-alginate for cells immobilization, investigated through microscopy analysis, reveals that the evolution of multicellularity in MaB-flocs, for all experiments.}, }
@article {pmid30465068, year = {2019}, author = {Hubert, J and Nesvorna, M and Kopecky, J and Erban, T and Klimov, P}, title = {Population and Culture Age Influence the Microbiome Profiles of House Dust Mites.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {1048-1066}, doi = {10.1007/s00248-018-1294-x}, pmid = {30465068}, issn = {1432-184X}, support = {17-12068S//Grantová Agentura České Republiky/ ; (No. 6.1933.2014/K Project Code 1933//Ministry of Education and Science of the Russian Federation/ ; No. 15-04-0s5185-a//the Russian Foundation for Basic Research/ ; }, mesh = {Animals ; *Bacteria/classification ; DNA Barcoding, Taxonomic ; *Fungi/classification ; *Microbiota ; Population Dynamics ; Pyroglyphidae/*microbiology/*physiology ; RNA, Bacterial/analysis ; RNA, Fungal/analysis ; RNA, Ribosomal, 16S/analysis ; RNA, Ribosomal, 18S/analysis ; Real-Time Polymerase Chain Reaction ; Species Specificity ; }, abstract = {Interactions with microorganisms might enable house dust mites (HDMs) to derive nutrients from difficult-to-digest structural proteins and to flourish in human houses. We tested this hypothesis by investigating the effects of changes in the mite culture growth and population of two HDM species on HDM microbiome composition and fitness. Growing cultures of laboratory and industrial allergen-producing populations of Dermatophagoides farinae (DFL and DFT, respectively) and Dermatophagoides pteronyssinus (DPL and DPT, respectively) were sampled at four time points. The symbiotic microorganisms of the mites were characterized by DNA barcode sequencing and quantified by qPCR using universal/specific primers. The population growth of mites and nutrient contents of mite bodies were measured and correlated with the changes in bacteria in the HDM microbiome. The results showed that both the population and culture age significantly influenced the microbiome profiles. Cardinium formed 93% and 32% of the total sequences of the DFL and DFT bacterial microbiomes, respectively, but this bacterial species was less abundant in the DPL and DPT microbiomes. Staphylococcus abundance was positively correlated with increased glycogen contents in the bodies of mites, and increased abundances of Aspergillus, Candida, and Kocuria were correlated with increased lipid contents in the bodies of mites. The xerophilic fungus Wallemia accounted for 39% of the fungal sequences in the DPL microbiome, but its abundance was low in the DPT, DFL, and DFT microbiomes. With respect to the mite culture age, we made three important observations: the mite population growth from young cultures was 5-8-fold higher than that from old cultures; specimens from old cultures had greater abundances of fungi and bacteria in their bodies; and yeasts predominated in the gut contents of specimens from young cultures, whereas filamentous mycelium prevailed in specimens from old cultures. Our results are consistent with the hypothesis that mites derive nutrients through associations with microorganisms.}, }
@article {pmid30460544, year = {2018}, author = {Koosha, M and Vatandoost, H and Karimian, F and Choubdar, N and Oshaghi, MA}, title = {Delivery of a Genetically Marked Serratia AS1 to Medically Important Arthropods for Use in RNAi and Paratransgenic Control Strategies.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1289-7}, pmid = {30460544}, issn = {1432-184X}, support = {30353//Tehran University of Medical Sciences and Health Services/ ; 33613//Tehran University of Medical Sciences and Health Services/ ; }, abstract = {Understanding how arthropod vectors acquire their bacteria is essential for implementation of paratransgenic and RNAi strategies using genetically modified bacteria to control vector-borne diseases. In this study, a genetically marked Serratia AS1 strain expressing the mCherry fluorescent protein (mCherry-Serratia) was used to test various acquisition routes in six arthropod vectors including Anopheles stephensi, Culex pipiens, Cx. quinquefaciatus, Cx. theileri, Phlebotomus papatasi, and Hyalomma dromedarii. Depending on the species, the bacteria were delivered to (i) mosquito larval breeding water, (ii) host skin, (iii) sugar bait, and (iv) males (paratransgenic). The arthropods were screened for the bacteria in their guts or other tissues. All the hematophagous arthropods were able to take the bacteria from the skin of their hosts while taking blood meal. The mosquitoes were able to take up the bacteria from the water at larval stages and to transfer them transstadially to adults and finally to transfer them to the water they laid eggs in. The mosquitoes were also able to acquire the bacteria from male sperm. The level of bacterial acquisition was influenced by blood feeding time and strategies (pool or vessel feeding), dipping in water and resting time of newly emerged adult mosquitoes, and the disseminated tissue/organ. Transstadial, vertical, and venereal bacterial acquisition would increase the sustainability of the modified bacteria in vector populations and decrease the need for supplementary release experiments whereas release of paratransgenic males that do not bite has fewer ethical issues. Furthermore, this study is required to determine if the modified bacteria can be introduced to arthropods in the same routes in nature.}, }
@article {pmid30459201, year = {2018}, author = {Hannigan, GD and Duhaime, MB and Ruffin, MT and Koumpouras, CC and Schloss, PD}, title = {Diagnostic Potential and Interactive Dynamics of the Colorectal Cancer Virome.}, journal = {mBio}, volume = {9}, number = {6}, pages = {}, pmid = {30459201}, issn = {2150-7511}, support = {P30 DK034933/DK/NIDDK NIH HHS/United States ; T32 AI007528/AI/NIAID NIH HHS/United States ; U01 CA086400/CA/NCI NIH HHS/United States ; }, mesh = {Bacteria/genetics/virology ; Bacteriophages/*genetics/isolation &amp; purification ; Cohort Studies ; Colorectal Neoplasms/*diagnosis/microbiology/*virology ; Feces/microbiology/virology ; Humans ; Metagenomics ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; Viruses/*genetics ; }, abstract = {Human viruses (those that infect human cells) have been associated with many cancers, largely due to their mutagenic and functionally manipulative abilities. Despite this, cancer microbiome studies have focused almost exclusively on bacteria instead of viruses. We began evaluating the cancer virome by focusing on colorectal cancer, a primary cause of morbidity and mortality throughout the world and a cancer linked to altered colonic bacterial community compositions but with an unknown association with the gut virome. We used 16S rRNA gene, whole shotgun metagenomic, and purified virus metagenomic sequencing of stool to evaluate the differences in human colorectal cancer virus and bacterial community composition. Through random forest modeling, we identified differences in the healthy and colorectal cancer viromes. The cancer-associated virome consisted primarily of temperate bacteriophages that were also predicted to be bacterium-virus community network hubs. These results provide foundational evidence that bacteriophage communities are associated with colorectal cancer and potentially impact cancer progression by altering the bacterial host communities.IMPORTANCE Colorectal cancer is a leading cause of cancer-related death in the United States and worldwide. Its risk and severity have been linked to colonic bacterial community composition. Although human-specific viruses have been linked to other cancers and diseases, little is known about colorectal cancer virus communities. We addressed this knowledge gap by identifying differences in colonic virus communities in the stool of colorectal cancer patients and how they compared to bacterial community differences. The results suggested an indirect role for the virome in impacting colorectal cancer by modulating the associated bacterial community. These findings both support the idea of a biological role for viruses in colorectal cancer and provide a new understanding of basic colorectal cancer etiology.}, }
@article {pmid30456756, year = {2019}, author = {Jung, MY and Kang, MS and Lee, KE and Lee, EY and Park, SJ}, title = {Paraburkholderia dokdonella sp. nov., isolated from a plant from the genus Campanula.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {2}, pages = {107-112}, doi = {10.1007/s12275-019-8500-5}, pmid = {30456756}, issn = {1976-3794}, mesh = {Bacterial Typing Techniques ; Base Composition ; Benzoquinones ; Burkholderiaceae/*classification/genetics/*isolation &amp; purification/physiology ; Campanulaceae/*microbiology ; DNA, Bacterial/analysis ; Fatty Acids/analysis ; Islands ; Nucleic Acid Hybridization ; Phosphatidylethanolamines/analysis ; Phosphatidylglycerols/analysis ; Phospholipids/analysis ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Republic of Korea ; Sequence Analysis, DNA ; Soil Microbiology ; Species Specificity ; Temperature ; Ubiquinone ; }, abstract = {The novel Gram-stain-negative, rod-shaped, aerobic bacterial strain DCR-13T was isolated from a native plant belonging to the genus Campanula on Dokdo, an island in the Republic of Korea. Comparative analysis of the 16S rRNA gene sequence indicated that this strain is closely related to Paraburkholderia peleae PP52-1T (98.43% 16S rRNA gene sequence similarity), Paraburkholderia oxyphila NBRC 105797T (98.42%), Paraburkholderia sacchari IPT 101T (98.28%), Paraburkholderia mimosarum NBRC 106338T (97.80%), Paraburkholderia denitrificans KIS30-44T (97.46%), and Paraburkholderia paradise WAT (97.45%). This analysis of the 16S rRNA gene sequence also suggested that DCR-13T and the six closely related strains formed a clade within the genus Paraburkholderia, but that DCR-13T was clearly separated from the established species. DCR-13T had ubiquinone 8 as its predominant respiratory quinone, and its genomic DNA G + C content was 63.9 mol%. The isolated strain grew at a pH of 6.0-8.0 (with an optimal pH of 6.5), 0-4% w/v NaCl (with an optimal level of 0%), and a temperature of 18-42°C (with an optimal temperature of 30°C). The predominant fatty acids were C16:0, summed feature 8 (C18:1ω7c/C18:1ω6c), C17:0 cyclo, C19:0 cyclo ω8c, summed feature 3 (C16:1ω6c/C16:1ω7c) and summed feature 2 (C12:0 aldehyde), and the major polar lipids were phosphatidylglycerol and phosphatidylethanolamine. On the basis of polyphasic evidence, it is proposed that strain DCR-13T (= KCTC 62811T = LMG 30889T) represents the type strain of a novel species, Paraburkholderia dokdonella sp. nov.}, }
@article {pmid30455213, year = {2018}, author = {Daru, BH and Bowman, EA and Pfister, DH and Arnold, AE}, title = {A novel proof of concept for capturing the diversity of endophytic fungi preserved in herbarium specimens.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1763}, pages = {}, pmid = {30455213}, issn = {1471-2970}, abstract = {Herbarium specimens represent important records of morphological and genetic diversity of plants that inform questions relevant to global change, including species distributions, phenology and functional traits. It is increasingly appreciated that plant microbiomes can influence these aspects of plant biology, but little is known regarding the historic distribution of microbes associated with plants collected in the pre-molecular age. If microbiomes can be observed reliably in herbarium specimens, researchers will gain a new lens with which to examine microbial ecology, evolution, species interactions. Here, we describe a method for accessing historical plant microbiomes from preserved herbarium specimens, providing a proof of concept using two plant taxa from the imperiled boreal biome (Andromeda polifolia and Ledum palustre subsp. groenlandicum, Ericaceae). We focus on fungal endophytes, which occur within symptomless plant tissues such as leaves. Through a three-part approach (i.e. culturing, cloning and next-generation amplicon sequencing via the Illumina MiSeq platform, with extensive controls), we examined endophyte communities in dried, pressed leaves that had been processed as regular herbarium specimens and stored at room temperature in a herbarium for four years. We retrieved only one endophyte in culture, but cloning and especially the MiSeq analysis revealed a rich community of foliar endophytes. The phylogenetic distribution and diversity of endophyte assemblages, especially among the Ascomycota, resemble endophyte communities from fresh plants collected in the boreal biome. We could distinguish communities of endophytes in each plant species and differentiate likely endophytes from fungi that could be surface contaminants. Taxa found by cloning were observed in the larger MiSeq dataset, but species richness was greater when subsets of the same tissues were evaluated with the MiSeq approach. Our findings provide a proof of concept for capturing endophyte DNA from herbarium specimens, supporting the importance of herbarium records as roadmaps for understanding the dynamics of plant-associated microbial biodiversity in the Anthropocene.This article is part of the theme issue 'Biological collections for understanding biodiversity in the Anthropocene'.}, }
@article {pmid30453516, year = {2018}, author = {Sharma, L and Oliveira, I and Raimundo, F and Torres, L and Marques, G}, title = {Soil Chemical Properties Barely Perturb the Abundance of Entomopathogenic Fusarium oxysporum: A Case Study Using a Generalized Linear Mixed Model for Microbial Pathogen Occurrence Count Data.}, journal = {Pathogens (Basel, Switzerland)}, volume = {7}, number = {4}, pages = {}, doi = {10.3390/pathogens7040089}, pmid = {30453516}, issn = {2076-0817}, support = {UID/MULTI/04621/2013 ; UID/AGR/04033/2013 ; POCI-01-0145-FEDER-006958//National Funds by FCT - Portuguese Foundation for Science and Technology; EcoVitis project; FEDER/COMPETE/POCI - Operacional Competitiveness and Internationalization Programme/ ; }, abstract = {Fusarium oxysporum exhibits insect pathogenicity-however, generalized concerns of releasing phytopathogens within agroecosystems marred its entomopathogenicity-related investigations. In a previous study, soils were sampled from Douro vineyards and adjacent hedgerows. In this study, 80 of those soils were analyzed for their chemical properties and were subsequently co-related with the abundance of entomopathogenic F. oxysporum, after insect baiting of soils with Galleria mellonella and Tenebrio molitor larvae. The soil chemical properties studied were organic matter content; total organic carbon; total nitrogen; available potassium; available phosphorus; exchangeable cations, such as K⁺, Na⁺, Ca2+, and Mg2+; pH; total acidity; degree of base saturation; and effective cation exchange capacity. Entomopathogenic F. oxysporum was found in 48 soils, i.e., 60% ± 5.47%, of the total soil samples. Out of the 1280 insect larvae used, 93, i.e., 7.26% ± 0.72%, were found dead by entomopathogenic F. oxysporum. Stepwise deletion of non-significant variables using a generalized linear model was followed by a generalized linear mixed model (GLMM). A higher C:N (logarithmized) (p < 0.001) and lower exchangeable K⁺ (logarithmized) (p = 0.008) were found significant for higher fungal abundance. Overall, this study suggests that entomopathogenic F. oxysporum is robust with regard to agricultural changes, and GLMM is a useful statistical tool for count data in ecology.}, }
@article {pmid30451146, year = {2019}, author = {Matsuyama, M and Gomez-Arango, LF and Fukuma, NM and Morrison, M and Davies, PSW and Hill, RJ}, title = {Breastfeeding: a key modulator of gut microbiota characteristics in late infancy.}, journal = {Journal of developmental origins of health and disease}, volume = {10}, number = {2}, pages = {206-213}, doi = {10.1017/S2040174418000624}, pmid = {30451146}, issn = {2040-1752}, abstract = {The objective of this study was to investigate the impact of the most commonly cited factors that may have influenced infants' gut microbiota profiles at one year of age: mode of delivery, breastfeeding duration and antibiotic exposure. Barcoded V3/V4 amplicons of bacterial 16S-rRNA gene were prepared from the stool samples of 52 healthy 1-year-old Australian children and sequenced using the Illumina MiSeq platform. Following the quality checks, the data were processed using the Quantitative Insights Into Microbial Ecology pipeline and analysed using the Calypso package for microbiome data analysis. The stool microbiota profiles of children still breastfed were significantly different from that of children weaned earlier (P<0.05), independent of the age of solid food introduction. Among children still breastfed, Veillonella spp. abundance was higher. Children no longer breastfed possessed a more 'mature' microbiota, with notable increases of Firmicutes. The microbiota profiles of the children could not be differentiated by delivery mode or antibiotic exposure. Further analysis based on children's feeding patterns found children who were breastfed alongside solid food had significantly different microbiota profiles compared to that of children who were receiving both breastmilk and formula milk alongside solid food. This study provided evidence that breastfeeding continues to influence gut microbial community even at late infancy when these children are also consuming table foods. At this age, any impacts from mode of delivery or antibiotic exposure did not appear to be discernible imprints on the microbial community profiles of these healthy children.}, }
@article {pmid30450083, year = {2018}, author = {Meisner, A and de Boer, W}, title = {Strategies to Maintain Natural Biocontrol of Soil-Borne Crop Diseases During Severe Drought and Rainfall Events.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2279}, pmid = {30450083}, issn = {1664-302X}, abstract = {In many parts of the world, agricultural ecosystems are increasingly exposed to severe drought, and rainfall events due to climate changes. This coincides with a higher vulnerability of crops to soil-borne diseases, which is mostly ascribed to decreased resistance to pathogen attacks. However, loss of the natural capacity of soil microbes to suppress soil-borne plant pathogens may also contribute to increased disease outbreaks. In this perspectives paper, we will discuss the effect of extreme weather events on pathogen-antagonist interactions during drought and rainfall events and upon recovery. We will focus on diseases caused by root-infecting fungi and oomycetes. In addition, we will explore factors that affect restoration of the balance between pathogens and other soil microbes. Finally, we will indicate potential future avenues to improve the resistance and/or recovery of natural biocontrol during, and after water stresses. As such, our perspective paper will highlight a knowledge gap that needs to be bridged to adapt agricultural ecosystems to changing climate scenarios.}, }
@article {pmid30449244, year = {2019}, author = {Sterlin, D and Fieschi, C and Malphettes, M and Larsen, M and Gorochov, G and Fadlallah, J}, title = {Immune/microbial interface perturbation in human IgA deficiency.}, journal = {Gut microbes}, volume = {10}, number = {3}, pages = {429-433}, doi = {10.1080/19490976.2018.1546520}, pmid = {30449244}, issn = {1949-0984}, abstract = {In a recently published article we report the metagenomic analysis of human gut microbiomes evolved in the absence of immunoglobulin A (IgA). We show that human IgA deficiency is not associated with massive quantitative perturbations of gut microbial ecology. While our study underlines a rather expected pathobiont expansion, we at the same time highlight a less expected depletion in some typically beneficial symbionts. We also show that IgM partially supply IgA deficiency, explaining the relatively mild clinical phenotype associated with the early steps of this condition. Microbiome studies in patients should consider potential issues such as cohort size, human genetic polymorphism and treatments. In this commentary, we discuss how such issues were taken into account in our own study.}, }
@article {pmid30448922, year = {2018}, author = {De Corte, D and Paredes, G and Yokokawa, T and Sintes, E and Herndl, GJ}, title = {Differential Response of Cafeteria roenbergensis to Different Bacterial and Archaeal Prey Characteristics.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1293-y}, pmid = {30448922}, issn = {1432-184X}, support = {P16085//Japan Society for the Promotion of Science/ ; Z194-B17//Austrian Science Fund/ ; P28781-B21//Austrian Science Fund/ ; P27696-B22//Austrian Science Fund/ ; PIEF-GA-2011-299860//FP7 People: Marie-Curie Actions/ ; 268595//European Research Council/International ; }, abstract = {In the marine environment, the abundance of Bacteria and Archaea is either controlled bottom-up via nutrient availability or top-down via grazing. Heterotrophic nanoflagellates (HNF) are mainly responsible for prokaryotic grazing losses besides viral lysis. However, the grazing specificity of HNF on specific bacterial and archaeal taxa is under debate. Bacteria and Archaea might have different nutritive values and surface properties affecting the growth rates of HNF. In this study, we offered different bacterial and archaeal strains with different morphologic and physiologic characteristics to Cafeteria roenbergensis, one of the most abundant and ubiquitous species of HNF in the ocean. Two Nitrosopumilus maritimus-related strains isolated from the northern Adriatic Sea (Nitrosopumilus adriaticus, Nitrosopumilus piranensis), two Nitrosococcus strains, and two fast growing marine Bacteria (Pseudoalteromonas sp. and Marinobacter sp.) were fed to Cafeteria cultures. Cafeteria roenbergensis exhibited high growth rates when feeding on Pseudoalteromonas sp., Marinobacter sp., and Nitrosopumilus adriaticus, while the addition of the other strains resulted in minimal growth. Taken together, our data suggest that the differences in growth of Cafeteria roenbergensis associated to grazing on different thaumarchaeal and bacterial strains are likely due to the subtle metabolic, cell size, and physiological differences between different bacterial and thaumarchaeal taxa. Moreover, Nitrosopumilus adriaticus experienced a similar grazing pressure by Cafeteria roenbergensis as compared to the other strains, suggesting that other HNF may also prey on Archaea which might have important consequences on the global biogeochemical cycles.}, }
@article {pmid30447886, year = {2019}, author = {Maayer, P and Aliyu, H and Cowan, DA}, title = {Reorganising the order Bacillales through phylogenomics.}, journal = {Systematic and applied microbiology}, volume = {42}, number = {2}, pages = {178-189}, doi = {10.1016/j.syapm.2018.10.007}, pmid = {30447886}, issn = {1618-0984}, mesh = {Bacillaceae/*classification ; DNA, Bacterial/genetics ; Genomics ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Bacterial classification at higher taxonomic ranks such as the order and family levels is currently reliant on phylogenetic analysis of 16S rRNA and the presence of shared phenotypic characteristics. However, these may not be reflective of the true genotypic and phenotypic relationships of taxa. This is evident in the order Bacillales, members of which are defined as aerobic, spore-forming and rod-shaped bacteria. However, some taxa are anaerobic, asporogenic and coccoid. 16S rRNA gene phylogeny is also unable to elucidate the taxonomic positions of several families incertae sedis within this order. Whole genome-based phylogenetic approaches may provide a more accurate means to resolve higher taxonomic levels. A suite of phylogenomic approaches were applied to re-evaluate the taxonomy of 80 representative taxa of eight families (and six family incertae sedis taxa) within the order Bacillales. This showed several anomalies in the current family and order level classifications including the existence of four Bacillaceae and two Paenibacillaceae &quot;family&quot; clades. Furthermore, the families Staphylococcaceae and Listeriaceae belong to the sister order Lactobacillales. Finally, we propose a consensus phylogenomic approach which may diminish algorithmic biases associated with single approaches and facilitate more accurate classification of a broad range of taxa at the higher taxonomic levels.}, }
@article {pmid30446738, year = {2019}, author = {Fernandez, VI and Yawata, Y and Stocker, R}, title = {A Foraging Mandala for Aquatic Microorganisms.}, journal = {The ISME journal}, volume = {13}, number = {3}, pages = {563-575}, doi = {10.1038/s41396-018-0309-4}, pmid = {30446738}, issn = {1751-7370}, abstract = {Aquatic environments harbor a great diversity of microorganisms, which interact with the same patchy, particulate, or diffuse resources by means of a broad array of physiological and behavioral adaptations, resulting in substantially different life histories and ecological success. To date, efforts to uncover and understand this diversity have not been matched by equivalent efforts to identify unifying frameworks that can provide a degree of generality and thus serve as a stepping stone to scale up microscale dynamics to predict their ecosystem-level consequences. In particular, evaluating the ecological consequences of different resource landscapes and of different microbial adaptations has remained a major challenge in aquatic microbial ecology. Here, inspired by Ramon Margalef's mandala for phytoplankton, we propose a foraging mandala for microorganisms in aquatic environments, which accounts for both the local environment and individual adaptations. This biophysical framework distills resource acquisition into two fundamental parameters: the search time for a new resource and the growth return obtained from encounter with a resource. We illustrate the foraging mandala by considering a broad range of microbial adaptations and environmental characteristics. The broad applicability of the foraging mandala suggests that it could be a useful framework to compare disparate microbial strategies in aquatic environments and to reduce the vast complexity of microbe-environment interactions into a minimal number of fundamental parameters.}, }
@article {pmid30446737, year = {2019}, author = {Rath, KM and Fierer, N and Murphy, DV and Rousk, J}, title = {Linking bacterial community composition to soil salinity along environmental gradients.}, journal = {The ISME journal}, volume = {13}, number = {3}, pages = {836-846}, doi = {10.1038/s41396-018-0313-8}, pmid = {30446737}, issn = {1751-7370}, abstract = {Salinization is recognized as a threat to soil fertility worldwide. A challenge in understanding the effects of salinity on soil microbial communities is the fact that it can be difficult to disentangle the effects of salinity from those of other variables that may co-vary with salinity. Here we use a trait-based approach to identify direct effects of salinity on soil bacterial communities across two salinity gradients. Through dose-response relationships between salinity and bacterial growth, we quantified distributions of the trait salt tolerance within the communities. Community salt tolerance was closely correlated with soil salinity, indicating a strong filtering effect of salinity on the bacterial communities. Accompanying the increases in salt tolerance were consistent shifts in bacterial community composition. We identified specific bacterial taxa that increased in relative abundances with community salt tolerance, which could be used as bioindicators for high community salt tolerance. A strong filtering effect was also observed for pH across the gradients, with pH tolerance of bacterial communities correlated to soil pH. We propose phenotypic trait distributions aggregated at the community level as a useful approach to study the role of environmental factors as filters of microbial community composition.}, }
@article {pmid30445447, year = {2019}, author = {Philips, J and Monballyu, E and Georg, S and De Paepe, K and Prévoteau, A and Rabaey, K and Arends, JBA}, title = {An Acetobacterium strain isolated with metallic iron as electron donor enhances iron corrosion by a similar mechanism as Sporomusa sphaeroides.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {2}, pages = {}, doi = {10.1093/femsec/fiy222}, pmid = {30445447}, issn = {1574-6941}, abstract = {Sporomusa sphaeroides related strains are to date the only homoacetogens known to increase metallic iron corrosion. The goal of this work was to isolate additional homoacetogenic bacteria capable of using Fe(0) as electron donor and to explore their extracellular electron transfer mechanism. Enrichments were started from anoxic corrosion products and yielded Acetobacterium as main homoacetogenic genus. Isolations were performed with a new procedure using plates with a Fe(0) powder top layer. An Acetobacterium strain, closely related to A. malicum and A. wieringae, was isolated, in addition to a S. sphaeroides strain. The Acetobacterium isolate significantly increased Fe(0) corrosion ((1.44 ± 0.16)-fold) compared to abiotic controls. The increase of corrosion by type strains ranged from (1.28 ± 0.13)-fold for A. woodii to (2.03 ± 0.22)-fold for S. sphaeroides. Hydrogen mediated the electron uptake from Fe(0) by the acetogenic isolates and tested type strains. Exchange of the medium and SEM imaging suggested that cells were attached to Fe(0). The corrosion enhancement mechanism is for all tested strains likely related to free extracellular components catalyzing hydrogen formation on the Fe(0) surface, or to the maintenance of low hydrogen concentrations on the Fe(0) surface by attached cells thereby thermodynamically favoring hydrogen formation.}, }
@article {pmid30443991, year = {2019}, author = {Schneider, S and Schintlmeister, A and Becana, M and Wagner, M and Woebken, D and Wienkoop, S}, title = {Sulfate is transported at significant rates through the symbiosome membrane and is crucial for nitrogenase biosynthesis.}, journal = {Plant, cell &amp; environment}, volume = {42}, number = {4}, pages = {1180-1189}, doi = {10.1111/pce.13481}, pmid = {30443991}, issn = {1365-3040}, support = {AGL2017-85775-R//Ministerio de Economía y Competitividad-Fondos Europeos de Desarrollo Regional/ ; W 1257-820//Austrian Science Fund/ ; }, abstract = {Legume-rhizobia symbioses play a major role in food production for an ever growing human population. In this symbiosis, dinitrogen is reduced (&quot;fixed&quot;) to ammonia by the rhizobial nitrogenase enzyme complex and is secreted to the plant host cells, whereas dicarboxylic acids derived from photosynthetically produced sucrose are transported into the symbiosomes and serve as respiratory substrates for the bacteroids. The symbiosome membrane contains high levels of SST1 protein, a sulfate transporter. Sulfate is an essential nutrient for all living organisms, but its importance for symbiotic nitrogen fixation and nodule metabolism has long been underestimated. Using chemical imaging, we demonstrate that the bacteroids take up 20-fold more sulfate than the nodule host cells. Furthermore, we show that nitrogenase biosynthesis relies on high levels of imported sulfate, making sulfur as essential as carbon for the regulation and functioning of symbiotic nitrogen fixation. Our findings thus establish the importance of sulfate and its active transport for the plant-microbe interaction that is most relevant for agriculture and soil fertility.}, }
@article {pmid30443603, year = {2018}, author = {Paver, SF and Muratore, D and Newton, RJ and Coleman, ML}, title = {Reevaluating the Salty Divide: Phylogenetic Specificity of Transitions between Marine and Freshwater Systems.}, journal = {mSystems}, volume = {3}, number = {6}, pages = {}, pmid = {30443603}, issn = {2379-5077}, abstract = {Marine and freshwater microbial communities are phylogenetically distinct, and transitions between habitat types are thought to be infrequent. We compared the phylogenetic diversity of marine and freshwater microorganisms and identified specific lineages exhibiting notably high or low similarity between marine and freshwater ecosystems using a meta-analysis of 16S rRNA gene tag-sequencing data sets. As expected, marine and freshwater microbial communities differed in the relative abundance of major phyla and contained habitat-specific lineages. At the same time, and contrary to expectations, many shared taxa were observed in both habitats. Based on several metrics, we found that Gammaproteobacteria, Alphaproteobacteria, Bacteroidetes, and Betaproteobacteria contained the highest number of closely related marine and freshwater sequences, suggesting comparatively recent habitat transitions in these groups. Using the abundant alphaproteobacterial group SAR11 as an example, we found evidence that new lineages, beyond the recognized LD12 clade, are detected in freshwater at low but reproducible abundances; this evidence extends beyond the 16S rRNA locus to core genes throughout the genome. Our results suggest that shared taxa are numerous, but tend to occur sporadically and at low relative abundance in one habitat type, leading to an underestimation of transition frequency between marine and freshwater habitats. Rare taxa with abundances near or below detection, including lineages that appear to have crossed the salty divide relatively recently, may possess adaptations enabling them to exploit opportunities for niche expansion when environments are disturbed or conditions change. IMPORTANCE The distribution of microbial diversity across environments yields insight into processes that create and maintain this diversity as well as potential to infer how communities will respond to future environmental changes. We integrated data sets from dozens of freshwater lake and marine samples to compare diversity across open water habitats differing in salinity. Our novel combination of sequence-based approaches revealed lineages that likely experienced a recent transition across habitat types. These taxa are promising targets for studying physiological constraints on salinity tolerance. Our findings contribute to understanding the ecological and evolutionary controls on microbial distributions, and open up new questions regarding the plasticity and adaptability of particular lineages.}, }
@article {pmid30442907, year = {2019}, author = {Zhou, W and Chow, KH and Fleming, E and Oh, J}, title = {Selective colonization ability of human fecal microbes in different mouse gut environments.}, journal = {The ISME journal}, volume = {13}, number = {3}, pages = {805-823}, doi = {10.1038/s41396-018-0312-9}, pmid = {30442907}, issn = {1751-7370}, support = {1 DP2 GM126893-01//U.S. Department of Health &amp; Human Services | National Institutes of Health (NIH)/International ; DP2 GM126893/GM/NIGMS NIH HHS/United States ; K22 AI119231/AI/NIAID NIH HHS/United States ; }, abstract = {Mammalian hosts constantly interact with diverse exogenous microbes, but only a subset of the microbes manage to colonize due to selective colonization resistance exerted by host genetic factors as well as the native microbiota of the host. An important question in microbial ecology and medical science is if such colonization resistance can discriminate closely related microbial species, or even closely related strains of the same species. Using human-mouse fecal microbiota transplantation and metagenomic shotgun sequencing, we reconstructed colonization patterns of human fecal microbes in mice with different genotypes (C57BL6/J vs. NSG) and with or without an intact gut microbiota. We found that mouse genotypes and the native mouse gut microbiota both exerted different selective pressures on exogenous colonizers: human fecal Bacteroides successfully established in the mice gut, however, different species of Bacteroides selectively enriched under different gut conditions, potentially due to a multitude of functional differences, ranging from versatility in nutrient acquisition to stress responses. Additionally, different clades of Bacteroides cellulosilyticus strains were selectively enriched in different gut conditions, suggesting that the fitness of conspecific microbial strains in a novel host environment could differ.}, }
@article {pmid30442070, year = {2019}, author = {Barnett, JA and Gibson, DL}, title = {H2Oh No! The importance of reporting your water source in your in vivo microbiome studies.}, journal = {Gut microbes}, volume = {10}, number = {3}, pages = {261-269}, doi = {10.1080/19490976.2018.1539599}, pmid = {30442070}, issn = {1949-0984}, abstract = {Water is a fundamental part of any in vivo microbiome experiment however, it is also one of the most overlooked and underreported variables within the literature. Currently there is no established standard for drinking water quality set by the Canadian Council on Animal Care. Most water treatment methods focus on inhibiting bacterial growth within the water while prolonging the shelf-life of bottles once poured. When reviewing the literature, it is clear that some water treatment methods, such as water acidification, alter the gut microbiome of experimental animals resulting in dramatic differences in disease phenotype progression. Furthermore, The Jackson Lab, one of the world's leading animal vendors, provides acidified water to their in-house animals and is often cited in the literature as having a dramatically different gut microbiome than animals acquired from either Charles River or Taconic. While we recognize that it is impossible to standardize water across all animal facilities currently conducting microbiome research, we hope that by drawing attention to the issue in this commentary, researchers will consider water source as an experimental variable and report their own water sources to facilitate experimental reproducibility. Moreover, researchers should be cognisant of potential phenotypic differences observed between commercial animal vendors due to changes in the gut microbiome as a result of various sources of water used.}, }
@article {pmid30430196, year = {2019}, author = {Wynants, E and Frooninckx, L and Crauwels, S and Verreth, C and De Smet, J and Sandrock, C and Wohlfahrt, J and Van Schelt, J and Depraetere, S and Lievens, B and Van Miert, S and Claes, J and Van Campenhout, L}, title = {Assessing the Microbiota of Black Soldier Fly Larvae (Hermetia illucens) Reared on Organic Waste Streams on Four Different Locations at Laboratory and Large Scale.}, journal = {Microbial ecology}, volume = {77}, number = {4}, pages = {913-930}, doi = {10.1007/s00248-018-1286-x}, pmid = {30430196}, issn = {1432-184X}, support = {RT 15/9 EDINCO//FOD Volksgezondheid, Veiligheid van de Voedselketen en Leefmilieu/ ; }, mesh = {Animal Feed/analysis/*microbiology ; Animals ; Belgium ; Diptera/growth &amp; development/*microbiology ; Larva/growth &amp; development/microbiology ; *Microbiota ; Solid Waste ; }, abstract = {This study aimed to gain insight into the microbial quality, safety and bacterial community composition of black soldier fly larvae (Hermetia illucens) reared at different facilities on a variety of organic waste streams. For seven rearing cycles, both on laboratory-scale and in large-scale facilities at several locations, the microbiota of the larvae was studied. Also samples of the substrate used and the residue (= leftover substrate after rearing, existing of non-consumed substrate, exuviae and faeces) were investigated. Depending on the sample, it was subjected to plate counting, Illumina Miseq sequencing and/or detection of specific food pathogens. The results revealed that the substrates applied at the various locations differed substantially in microbial numbers as well as in the bacterial community composition. Furthermore, little similarity was observed between the microbiota of the substrate and that of the larvae reared on that substrate. Despite substantial differences between the microbiota of larvae reared at several locations, 48 species-level operational taxonomic units (OTUs) were shared by all larvae, among which most belonged to the phyla Firmicutes and Proteobacteria. Although the substrate is assumed to be an important source of bacteria, our results suggest that a variety of supposedly interacting factors-both abiotic and biotic-are likely to affect the microbiota in the larvae. In some larvae and/or residue samples, potential foodborne pathogens such as Salmonella and Bacillus cereus were detected, emphasising that decontamination technologies are required when the larvae are used in feed, just as for other feed ingredients, or eventually in food.}, }
@article {pmid30429840, year = {2018}, author = {Mas-Carrió, E and Dini-Andreote, F and Brossi, MJL and Salles, JF and Olff, H}, title = {Organic Amendment Under Increasing Agricultural Intensification: Effects on Soil Bacterial Communities and Plant Productivity.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2612}, pmid = {30429840}, issn = {1664-302X}, abstract = {The soil microbiome is a complex living network that plays essential roles in agricultural systems, regardless of the level of intensification. However, the effects of agricultural management on the soil microbiome and the association with plant productivity remain largely unclear. Here, we studied the responses of three soil systems displaying distinct levels of agriculture intensiveness (i.e., natural, organic, and conventional soil management regimes) to experimentally manipulated organic farming amendments (i.e., dung and earthworms). We aimed at (i) identifying the effect on plant productivity and (ii) elucidating the degree of shifts in bacterial communities in response to the applied organic amendments. We found plant productivity to be lower with increasing agricultural intensification. Bacterial communities shifted distinctively for each soil management regime to the organic amendments applied. In brief, greater changes were observed in the Conventional management comparatively to the Organic and Natural management, an effect largely driven by dung addition. Moreover, we found evidence that the level of agricultural intensiveness also affects the timespan for these shifts. For instance, while the Natural system reached a relatively stable community composition before the end of the experiment, treatments on the conventional soil management regime did not. Random forest analyses further revealed an increasing impact of introduced taxa from dung addition aligned with increasing agricultural intensification. These analyses suggested that earthworms regulate the introduction of species from dung into the soil bacterial community. Collectively, our results contribute to a better understanding of the outcomes of organic amendments on soils under distinct levels of agriculture intensiveness, with implications for further development in soil restorations practices.}, }
@article {pmid30429832, year = {2018}, author = {Bruno, A and Sandionigi, A and Bernasconi, M and Panio, A and Labra, M and Casiraghi, M}, title = {Changes in the Drinking Water Microbiome: Effects of Water Treatments Along the Flow of Two Drinking Water Treatment Plants in a Urbanized Area, Milan (Italy).}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2557}, pmid = {30429832}, issn = {1664-302X}, abstract = {While safe and of high quality, drinking water can host an astounding biodiversity of microorganisms, dismantling the belief of its &quot;biological simplicity.&quot; During the very few years, we are witnessing an exponential growth in scientific publications, exploring the ecology hidden in drinking water treatment plants (DWTPs) and drinking water distribution system (DWDS). We focused on what happens to the microbial communities from source water (groundwater) throughout the main steps of the potabilization process of a DWTP, located in an urbanized area in Northern Italy. Samples were processed by a stringent water filtration to retain even the smallest environmental bacteria and then analyzed with High-Throughput DNA Sequencing (HTS) techniques. We showed that carbon filters harbored a microbial community seeding and shaping water microbiota downstream, introducing a significant variation on incoming (groundwater) microbial community. Chlorination did not instantly affect the altered microbiota. We were also able to correctly predict (through machine learning analysis) samples belonging to groundwater (overall accuracy was 0.71), but the assignation was not reliable with carbon filter samples, which were incorrectly predicted as chlorination samples. The presence and abundance of specific microorganisms allowed us to hypothesize their role as indicators. In particular, Candidatus Adlerbacteria (Parcubacteria), together with microorganisms belonging to Alphaproteobacteria and Gammaproteobacteria, characterized treated water, but not raw water. An exception, confirming our hypothesis, is given by the samples downstream the filters renewal, which had a composition resembling groundwater. Volatility analysis illustrated how carbon filters represented an ecosystem that is stable over time, probably bearing the environmental conditions that promote the survival and growth of this peculiar microbial community.}, }
@article {pmid30429514, year = {2018}, author = {De Vrieze, J and Ijaz, UZ and Saunders, AM and Theuerl, S}, title = {Terminal restriction fragment length polymorphism is an &quot;old school&quot; reliable technique for swift microbial community screening in anaerobic digestion.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {16818}, pmid = {30429514}, issn = {2045-2322}, abstract = {The microbial community in anaerobic digestion has been analysed through microbial fingerprinting techniques, such as terminal restriction fragment length polymorphism (TRFLP), for decades. In the last decade, high-throughput 16S rRNA gene amplicon sequencing has replaced these techniques, but the time-consuming and complex nature of high-throughput techniques is a potential bottleneck for full-scale anaerobic digestion application, when monitoring community dynamics. Here, the bacterial and archaeal TRFLP profiles were compared with 16S rRNA gene amplicon profiles (Illumina platform) of 25 full-scale anaerobic digestion plants. The α-diversity analysis revealed a higher richness based on Illumina data, compared with the TRFLP data. This coincided with a clear difference in community organisation, Pareto distribution, and co-occurrence network statistics, i.e., betweenness centrality and normalised degree. The β-diversity analysis showed a similar clustering profile for the Illumina, bacterial TRFLP and archaeal TRFLP data, based on different distance measures and independent of phylogenetic identification, with pH and temperature as the two key operational parameters determining microbial community composition. The combined knowledge of temporal dynamics and projected clustering in the β-diversity profile, based on the TRFLP data, distinctly showed that TRFLP is a reliable technique for swift microbial community dynamics screening in full-scale anaerobic digestion plants.}, }
@article {pmid30427665, year = {2018}, author = {Dang, H and Kanitkar, YH and Stedtfeld, RD and Hatzinger, PB and Hashsham, SA and Cupples, AM}, title = {Abundance of Chlorinated Solvent and 1,4-Dioxane Degrading Microorganisms at Five Chlorinated Solvent Contaminated Sites Determined via Shotgun Sequencing.}, journal = {Environmental science &amp; technology}, volume = {52}, number = {23}, pages = {13914-13924}, doi = {10.1021/acs.est.8b04895}, pmid = {30427665}, issn = {1520-5851}, abstract = {Shotgun sequencing was used for the quantification of taxonomic and functional biomarkers associated with chlorinated solvent bioremediation in 20 groundwater samples (five sites), following bioaugmentation with SDC-9. The analysis determined the abundance of (1) genera associated with chlorinated solvent degradation, (2) reductive dehalogenase (RDases) genes, (3) genes associated with 1,4-dioxane removal, (4) genes associated with aerobic chlorinated solvent degradation, and (5) D. mccartyi genes associated with hydrogen and corrinoid metabolism. The taxonomic analysis revealed numerous genera previously linked to chlorinated solvent degradation, including Dehalococcoides, Desulfitobacterium, and Dehalogenimonas. The functional gene analysis indicated vcrA and tceA from D. mccartyi were the RDases with the highest relative abundance. Reads aligning with both aerobic and anaerobic biomarkers were observed across all sites. Aerobic solvent degradation genes, etnC or etnE, were detected in at least one sample from each site, as were pmoA and mmoX. The most abundant 1,4-dioxane biomarker detected was Methylosinus trichosporium OB3b mmoX. Reads aligning to thmA or Pseudonocardia were not found. The work illustrates the importance of shotgun sequencing to provide a more complete picture of the functional abilities of microbial communities. The approach is advantageous over current methods because an unlimited number of functional genes can be quantified.}, }
@article {pmid30426401, year = {2018}, author = {Ver Heul, A and Planer, J and Kau, AL}, title = {The Human Microbiota and Asthma.}, journal = {Clinical reviews in allergy &amp; immunology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12016-018-8719-7}, pmid = {30426401}, issn = {1559-0267}, support = {K08 AI113184/AI/NIAID NIH HHS/United States ; K08AI113184//National Institute of Allergy and Infectious Diseases (US)/ ; 5T32DK077653-27//National Institute of Diabetes and Digestive and Kidney Diseases/ ; Faculty Development Award//AAAAI Foundation/ ; }, abstract = {Over the last few decades, advances in our understanding of microbial ecology have allowed us to appreciate the important role of microbial communities in maintaining human health. While much of this research has focused on gut microbes, microbial communities in other body sites and from the environment are increasingly recognized in human disease. Here, we discuss recent advances in our understanding of host-microbiota interactions in the development and manifestation of asthma focusing on three distinct microbial compartments. First, environmental microbes originating from house dust, pets, and farm animals have been linked to asthma pathogenesis, which is often connected to their production of bioactive molecules such as lipopolysaccharide. Second, respiratory microbial communities, including newly appreciated populations of microbes in the lung have been associated with allergic airway inflammation. Current evidence suggests that the presence of particular microbes, especially Streptococcus, Haemophilus, and Morexella species within the airway may shape local immune responses and alter the severity and manifestations of airway inflammation. Third, the gut microbiota has been implicated in both experimental models and clinical studies in predisposing to asthma. There appears to be a &quot;critical window&quot; of colonization that occurs during early infancy in which gut microbial communities shape immune maturation and confer susceptibility to allergic airway inflammation. The mechanisms by which gut microbial communities influence lung immune responses and physiology, the &quot;gut-lung axis,&quot; are still being defined but include the altered differentiation of immune cell populations important in asthma and the local production of metabolites that affect distal sites. Together, these findings suggest an intimate association of microbial communities with host immune development and the development of allergic airway inflammation. Improved understanding of these relationships raises the possibility of microbiota-directed therapies to improve or prevent asthma.}, }
@article {pmid30425147, year = {2018}, author = {Su, X and Jing, G and McDonald, D and Wang, H and Wang, Z and Gonzalez, A and Sun, Z and Huang, S and Navas, J and Knight, R and Xu, J}, title = {Identifying and Predicting Novelty in Microbiome Studies.}, journal = {mBio}, volume = {9}, number = {6}, pages = {}, pmid = {30425147}, issn = {2150-7511}, mesh = {*Computational Biology ; *Databases, Factual ; Humans ; Microbiota/*genetics ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {With the expansion of microbiome sequencing globally, a key challenge is to relate new microbiome samples to the existing space of microbiome samples. Here, we present Microbiome Search Engine (MSE), which enables the rapid search of query microbiome samples against a large, well-curated reference microbiome database organized by taxonomic similarity at the whole-microbiome level. Tracking the microbiome novelty score (MNS) over 8 years of microbiome depositions based on searching in more than 100,000 global 16S rRNA gene amplicon samples, we detected that the structural novelty of human microbiomes is approaching saturation and likely bounded, whereas that in environmental habitats remains 5 times higher. Via the microbiome focus index (MFI), which is derived from the MNS and microbiome attention score (MAS), we objectively track and compare the structural-novelty and attracted-attention scores of individual microbiome samples and projects, and we predict future trends in the field. For example, marine and indoor environments and mother-baby interactions are likely to receive disproportionate additional attention based on recent trends. Therefore, MNS, MAS, and MFI are proposed &quot;alt-metrics&quot; for evaluating a microbiome project or prospective developments in the microbiome field, both of which are done in the context of existing microbiome big data.IMPORTANCE We introduce two concepts to quantify the novelty of a microbiome. The first, the microbiome novelty score (MNS), allows identification of microbiomes that are especially different from what is already sequenced. The second, the microbiome attention score (MAS), allows identification of microbiomes that have many close neighbors, implying that considerable scientific attention is devoted to their study. By computing a microbiome focus index based on the MNS and MAS, we objectively track and compare the novelty and attention scores of individual microbiome samples and projects over time and predict future trends in the field; i.e., we work toward yielding fundamentally new microbiomes rather than filling in the details. Therefore, MNS, MAS, and MFI can serve as &quot;alt-metrics&quot; for evaluating a microbiome project or prospective developments in the microbiome field, both of which are done in the context of existing microbiome big data.}, }
@article {pmid30423502, year = {2019}, author = {Ntagia, E and Fiset, E and da Silva Lima, L and Pikaar, I and Zhang, X and Jeremiasse, AW and Prévoteau, A and Rabaey, K}, title = {Anode materials for sulfide oxidation in alkaline wastewater: An activity and stability performance comparison.}, journal = {Water research}, volume = {149}, number = {}, pages = {111-119}, doi = {10.1016/j.watres.2018.11.004}, pmid = {30423502}, issn = {1879-2448}, abstract = {Electrochemical sulfide removal can be attractive as a zero-chemical-input approach for treatment of waste streams such as spent caustics coupled to caustic recovery. A key concern is possible decline in catalytic activity, due to passivation from deposited elemental sulfur (S0) on the anode surface and stability limitation, due to sulfide oxidation under highly alkaline conditions. In this study, six commercially available electrode materials (Ir Mixed Metal Oxide (MMO), Ru MMO, Pt/IrOx, Pt, PbOx and TiO2/IrTaO2 coated titanium-based electrodes) were tested to investigate the impact of the electrocatalyst on the process efficiency in terms of sulfide removal and final product of sulfide oxidation, as well as to determine the stability of the electrocatalyst under high sulfide concentrations (50 mM Na2S) and high alkalinity (pH > 12). Short-term experiments showed that the catalyst type impacts the anode potential and the sulfide oxidation reaction products. Longer-term experiments under current densities up to 200 A m-2 showed a high differentiation in stability performance among the catalysts. Ru MMO was the most active towards sulfide oxidation with a coulombic efficiency of 63.2 ± 0.5% at an average anode potential of 0.92 ± 0.17 V vs SHE. Ir MMO was the most stable, preserving 100% of its original catalyst loading during the tests. The results demonstrated that Ru MMO and Ir MMO were the most suitable electrode materials for sulfide oxidation under highly alkaline conditions, while the need for establishing a good trade-off between activity, stability and cost still persists.}, }
@article {pmid30423115, year = {2018}, author = {Romano, S and Ansorge, R}, title = {Scientific communication strategies of microbiologists in the era of social media.}, journal = {FEMS microbiology letters}, volume = {365}, number = {23}, pages = {}, doi = {10.1093/femsle/fny264}, pmid = {30423115}, issn = {1574-6968}, abstract = {Over the last decades, the world of communication underwent drastic changes, and internet and social media emerged as essential vehicles for exchanging information. Following these trends, it is important that scientists adapt to changes and adopt optimal strategies to communicate with colleagues, lay people and institutions. We conducted an online survey to investigate the communication strategies of microbiologists and their colleagues from other disciplines. We collected data from 527 scholars from 57 countries, with ∼42% of them being microbiologists. We focused particularly on social media and found that >80% of participants used them for work, and that ∼50% of interviewed actively shared and gathered scientific contents from social media. Compared to colleagues from other fields, microbiologists were less averse to use social media for work and were also less accustomed to use pre-prints as a source and vehicle of information. However, a large proportion of microbiologists declared to have planned pre-print publications in the future. Surprisingly, our data revealed that age is a poor predictor of social media usage, but it is strongly associated with the type of social media used, the activity undertaken on them and the attitude towards pre-print publications. Considering the kaleidoscopic variety of scientific communication tools, our data might help to optimize the scientific promotion strategies among microbiologists.}, }
@article {pmid30421114, year = {2018}, author = {Chung, YA and Jumpponen, A and Rudgers, JA}, title = {Divergence in Diversity and Composition of Root-Associated Fungi Between Greenhouse and Field Studies in a Semiarid Grassland.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1277-y}, pmid = {30421114}, issn = {1432-184X}, support = {1601210//Division of Environmental Biology/ ; 1456955//Division of Environmental Biology/ ; 1748133//National Science Foundation/ ; 1440478//National Science Foundation/ ; }, abstract = {Investigations of plant-soil feedbacks (PSF) and plant-microbe interactions often rely exclusively on greenhouse experiments, yet we have little understanding of how, and when, results can be extrapolated to explain phenomena in nature. A systematic comparison of microbial communities using the same host species across study environments can inform the generalizability of such experiments. We used Illumina MiSeq sequencing to characterize the root-associated fungi of two foundation grasses from a greenhouse PSF experiment, a field PSF experiment, field monoculture stands, and naturally occurring resident plants in the field. A core community consisting < 10% of total fungal OTU richness but > 50% of total sequence abundance occurred in plants from all study types, demonstrating the ability of field and greenhouse experiments to capture the dominant component of natural communities. Fungal communities were plant species-specific across the study types, with the core community showing stronger host specificity than peripheral taxa. Roots from the greenhouse and field PSF experiments had lower among sample variability in community composition and higher diversity than those from naturally occurring, or planted monoculture plants from the field. Core and total fungal composition differed substantially across study types, and dissimilarity between fungal communities did not predict plant-soil feedbacks measured in experiments. These results suggest that rhizobiome assembly mechanisms in nature differ from the dynamics of short-term, inoculation studies. Our results validate the efficacy of common PSF experiment designs to test soil inoculum effects, and highlight the challenges of scaling the underlying microbial mechanisms of plant responses from whole-community inoculation experiments to natural ecosystems.}, }
@article {pmid30421109, year = {2019}, author = {La, A and Perré, P and Taidi, B}, title = {Process for symbiotic culture of Saccharomyces cerevisiae and Chlorella vulgaris for in situ CO2 mitigation.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {2}, pages = {731-745}, doi = {10.1007/s00253-018-9506-3}, pmid = {30421109}, issn = {1432-0614}, mesh = {Carbon Dioxide/*metabolism ; Chlorella vulgaris/*growth &amp; development/*metabolism ; Coculture Techniques/*methods ; Culture Media/chemistry ; Saccharomyces cerevisiae/*growth &amp; development/*metabolism ; *Symbiosis ; }, abstract = {Industrial biotechnology relies heavily on fermentation processes that release considerable amounts of CO2. Apart from the fact that this CO2 represents a considerable part of the organic substrate, it has a negative impact on the environment. Microalgae cultures have been suggested as potential means of capturing the CO2 with further applications in high-value compounds production or directly for feed applications. We developed a sustainable process based on a mixed co-dominant culture of Saccharomyces cerevisiae and Chlorella vulgaris where the CO2 production and utilization controlled the microbial ecology of the culture. By mixing yeast and microalga in the same culture, the CO2 is produced in dissolved form and is available to the microalga avoiding degassing and dissolution phenomena. With this process, the CO2 production and utilization rates were balanced and a mutual symbiosis between the yeast and the microalga was set up in the culture. In this study, the reutilization of CO2 and growth of C. vulgaris was demonstrated. The two organism populations were balanced at approximately 20 × 106 cells ml-1 and almost all the CO2 produced by yeast was reutilized by microalga within 168 h of culture. The C. vulgaris inoculum preparation played a key role in establishing co-dominance of the two organisms. Other key factors in establishing symbiosis were the inoculum ratio of the two organisms and the growth medium design. A new method allowed the independent enumeration of each organism in a mixed culture. This study could provide a basis for the development of green processes of low environmental impact.}, }
@article {pmid30419469, year = {2019}, author = {Miao, Y