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Bibliography on: Biodiversity and Metagenomics

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ESP: PubMed Auto Bibliography 08 Feb 2023 at 01:30 Created: 

Biodiversity and Metagenomics

If evolution is the only light in which biology makes sense, and if variation is the raw material upon which selection works, then variety is not merely the spice of life, it is the essence of life — the sine qua non without which life could not exist. To understand biology, one must understand its diversity. Historically, studies of biodiversity were directed primarily at the realm of multicellular eukaryotes, since few tools existed to allow the study of non-eukaryotes. Because metagenomics allows the study of intact microbial communities, without requiring individual cultures, it provides a tool for understanding this huge, hitherto invisible pool of biodiversity, whether it occurs in free-living communities or in commensal microbiomes associated with larger organisms.

Created with PubMed® Query: biodiversity metagenomics NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2023-02-07
CmpDate: 2023-02-07

Li Y, Jones FG, Zhang B, et al (2023)

The effect of short-term fallowing on the microbial communities in forest soil cultivated with ginseng: Preliminary research.

PeerJ, 11:e14758.

BACKGROUND: Continuous cultivation of ginseng crops in fixed plots can lead to disease outbreaks, yield losses and replanting failures. Fallow periods can help restore soil health and increase the sustainability of agricultural systems; however, taking land out of production for extended periods is often not feasible. Short-term fallow periods could restore soil health, but few studies have examined the effects of short-term fallow treatment on the health of soil in ginseng fields.

METHODS: In this preliminary study, we used metagenomic analysis to assess changes in the abundance of major ginseng pathogens and soil health overall following a short-term fallow period in a region in the Changbai Mountains. A sample from a forest plot (Hx0ks), was compared to a sample from a field where ginseng was previously cultivated and then had been left fallow for two years (Hx2), and a sample from a field that had been fallow for two years and was subsequently replanted with ginseng (Clsd).

RESULTS: Soil that was fallow for two years, and then replanted with ginseng, showed reduced nutrient content and lower diversity of soil bacterial and fungal communities than soil that remained fallow. Candidatus Solibacter (5%) and Rhizomicrobium (3%) were the most abudant bacterial genera in Hx2. Rhizomicrobium (4%) and Gemmatimonas (3%) were the most abundant bacterial genera in Clsd. Mortierella (22%) and Peziza (12%) dominated the fungal community in Hx2. Lecanicillium (38%) and Mortierella (13%) dominated the fungal community in Clsd. Fallow periods also increased the functional diversity of soil as predicted by PICRUSt and decreased the relative abundance of the pathogenic fungi.

CONCLUSIONS: Preliminary findings were consistent with the hypothesis that fallow management in ginseng cultivation can improve soil microbial community structure and function and reduces the number of plant pathogens; however, testing this hypothesis will require replicated plots.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Chen Z, Yang H, Fu H, et al (2022)

Gut bacterial species in late trimester of pregnant sows influence the occurrence of stillborn piglet through pro-inflammation response.

Frontiers in immunology, 13:1101130.

Maternal gut microbiota is an important regulator for the metabolism and immunity of the fetus during pregnancy. Recent studies have indicated that maternal intestinal microbiota is closely linked to the development of fetus and infant health. Some bacterial metabolites are considered to be directly involved in immunoregulation of fetus during pregnancy. However, the detailed mechanisms are largely unknown. In this study, we exploited the potential correlation between the gut microbiota of pregnant sows and the occurrence of stillborn piglets by combining the 16S rRNA gene and metagenomic sequencing data, and fecal metabolome in different cohorts. The results showed that several bacterial species from Bacteroides, potential pathogens, and LPS-producing bacteria exhibited significantly higher abundances in the gut of sows giving birth to stillborn piglets. Especially, Bacteroides fragilis stood out as the key driver in both tested cohorts and showed the most significant association with the occurrence of stillborn piglets in the DN1 cohort. However, several species producing short-chain fatty acids (SCFAs), such as Prevotella copri, Clostridium butyricum and Faecalibacterium prausnitzii were enriched in the gut of normal sows. Functional capacity analysis of gut microbiome revealed that the pathways associated with infectious diseases and immune diseases were enriched in sows giving birth to stillborn piglets. However, energy metabolism had higher abundance in normal sows. Fecal metabolome profiling analysis found that Lysophosphatidylethanolamine and phosphatidylethanolamine which are the main components of cell membrane of Gram-negative bacteria showed significantly higher concentration in stillbirth sows, while SCFAs had higher concentration in normal sows. These metabolites were significantly associated with the stillborn-associated bacterial species including Bacteroides fragilis. Lipopolysaccharide (LPS), IL-1β, IL-6, FABP2, and zonulin had higher concentration in the serum of stillbirth sows, indicating increased intestinal permeability and pro-inflammatory response. The results from this study suggested that certain sow gut bacterial species in late trimester of pregnancy, e.g., an excess abundance of Bacteroides fragilis, produced high concentration of LPS which induced sow pro-inflammatory response and might cause the death of the relatively weak piglets in a farrow. This study provided novel evidences about the effect of maternal gut microbiota on the fetus development and health.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Zhao G, Qi M, Wang Q, et al (2023)

Gut microbiome variations in Rhinopithecus roxellanae caused by changes in the environment.

BMC genomics, 24(1):62.

BACKGROUND: The snub-nosed monkey (Rhinopithecus roxellanae) is an endangered animal species mainly distributed in China and needs to be protected. Gut microbiome is an important determinant of animal health and population survival as it affects the adaptation of the animals to different foods and environments under kinetic changes of intrinsic and extrinsic factors. Therefore, this study aimed to elucidate gut fecal microbiome profiles of snub-nosed monkeys affected by several extrinsic and intrinsic factors, including raising patterns (captive vs. wild), age, sex, and diarrheal status to provide a reference for making protection strategies.

RESULTS: The 16S rRNA gene sequencing was firstly used to pre-check clustering of 38 fecal samples from the monkeys including 30 wild and 8 captive (5 healthy and 3 diarrheal) from three Regions of Shennongjia Nature Reserve, Hubei Province, China. Then the 24 samples with high-quality DNA from 18 wild and 6 captive (4 healthy and 2 diarrheal) monkeys were subjected to shotgun metagenomic sequencing to characterize bacterial gut microbial communities. We discovered that the raising pattern (captive and wild) rather than age and sex was the predominant factor attributed to gut microbiome structure and proportionality. Wild monkeys had significantly higher bacterial diversity and lower Bacteroidetes/Firmicutes ratios than captive animals. Moreover, the gut microbiomes in wild healthy monkeys were enriched for the genes involved in fatty acid production, while in captive animals, genes were enriched for vitamin biosynthesis and metabolism and amino acid biosynthesis from carbohydrate intermediates. Additionally, a total of 37 antibiotic resistant genes (ARG) types were detected. Unlike the microbiome diversity, the captive monkeys have a higher diversity of ARG than the wild animals.

CONCLUSION: Taken together, we highlight the importance of self-reprogramed metabolism in the snub-nosed monkey gut microbiome to help captive and wild monkeys adapt to different intrinsic and extrinsic environmental change.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Chang D, Gupta VK, Hur B, et al (2023)

GMWI-webtool: a user-friendly browser application for assessing health through metagenomic gut microbiome profiling.

Bioinformatics (Oxford, England), 39(2):.

SUMMARY: We recently introduced the Gut Microbiome Wellness Index (GMWI), a stool metagenome-based indicator for assessing health by determining the likelihood of disease given the state of one's gut microbiome. The calculation of our wellness index depends on the relative abundances of health-prevalent and health-scarce species. Encouragingly, GMWI has already been utilized in various studies focusing on differences in the gut microbiome between cases and controls. Herein, we introduce the GMWI-webtool, a user-friendly browser application that computes GMWI, health-prevalent/-scarce species' relative abundances, and α-diversities from stool shotgun metagenome taxonomic profiles. Users of our interactive online tool can visualize their results and compare them side-by-side with those from our pooled reference dataset of metagenomes, as well as export data in.csv format and high-resolution figures.

GMWI-webtool is freely available here: https://gmwi-webtool.github.io/.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Mi T, Jin Y, Che Y, et al (2023)

Profiling the composition and metabolic functions of microbial community in pellicle-forming radish paocai.

International journal of food microbiology, 388:110087.

Pellicle formation is an obvious indicator of spoilage and is followed by a loss of flavor in a variety of fermented vegetables. In this study, the pellicle-forming microorganisms were isolated using culture-dependent approaches, then a comparative analysis between the pellicle-forming (PF) radish paocai and normal fermented paocai in the diversity and function of microbial community was conducted by metagenome sequencing. Based on a pairwise t-test and OPLS-DA analysis, diallyl sulfide, (z)-1-allyl-2-(prop-1-en-1-yl) disulfane, and terpineol were considered to be the main components responsible for the unpleasant flavor of PF paocai. Yarrowia spp., Enterobacter spp., and Pichia spp. were the main pellicle-forming microorganisms. All 17 isolated Enterobacter strains showed pectinase-producing and cellulase-producing abilities, and 3 isolated Pichia strains showed gas-producing capacity. According to LEfSe analysis based on metagenomes, unclassified_g__Citrobacter and Yarrowia lipolytica were the uppermost biomarkers that distinguished the PF paocai from normal paocai. Unclassified_g__Lactobacillus and Lactobacillus plantarum were found to be actively engaged in starch and sucrose metabolism, cysteine and methionine metabolism, galactose metabolism, fructose and mannose metabolism, lysine biosynthesis, fatty acid biosynthesis, and arginine biosynthesis, all of which contributed to the flavor formation of paocai. Combining the results of metagenome sequencing with the data obtained based on the culture-dependent method, we could deduce that the growth of Yarrowia lipolytica first promoted the increase of pH and the formation of pellicle, which provided a suitable niche for the growth of some harmful bacteria such as Enterobacter, Citrobacter, and Serratia. These hazardous bacteria then worked in concert to induce the odorous stench and texture softening of paocai, as well as more pellicle formation.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Sun S, Wang Y, Xu C, et al (2023)

Reconstruction of microbiome and functionality accelerated crude oil biodegradation of 2,4-DCP-oil-contaminated soil systems using composite microbial agent B-Cl.

Journal of hazardous materials, 447:130808.

Biodegradation is one of the safest and most economical methods for the elimination of toxic chlorophenols and crude oil from the environment. In this study, aerobic degradation of the aforementioned compounds by composite microbial agent B-Cl, which consisted of Bacillus B1 and B2 in a 3:2 ratio, was analyzed. The biodegradation mechanism of B-Cl was assessed based on whole genome sequencing, Fourier transform infrared spectroscopy and gas chromatographic analyses. B-Cl was most effective at reducing Cl[-] concentrations (65.17%) and crude oil biodegradation (59.18%) at 7 d, which was when the content of alkanes ≤ C30 showed the greatest decrease. Furthermore, adding B-Cl solution to soil significantly decreased the 2,4-DCP and oil content to below the detection limit and by 80.68%, respectively, and reconstructed of the soil microbial into a system containing more CPs-degrading (exaA, frmA, L-2-HAD, dehH, ALDH, catABE), aromatic compounds-degrading (pcaGH, catAE, benA-xylX, paaHF) and alkane- and fatty acid-degrading (alkB, atoB, fadANJ) microorganisms. Moreover, the presence of 2,4-DCP was the main hinder of the observed effects. This study demonstrates the importance of adding B-Cl solution to determine the interplay of CPs with microbes and accelerating oil degradation, which can be used for in-situ bioremediation of CPs and oil-contaminated soil.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Luo ZH, Li Q, Chen N, et al (2023)

Genome-resolved metagenomics reveals depth-related patterns of microbial community structure and functions in a highly stratified, AMD overlaying mine tailings.

Journal of hazardous materials, 447:130774.

Acid mine drainage (AMD) is a worldwide environmental problem, yet bioremediation is hampered by a limited knowledge of the reductive microbial processes in the AMD ecosystem. Here, we generate extensive metagenome and geochemical datasets to investigate how microbial populations and metabolic capacities driving major element cycles are structured in a highly stratified, AMD overlaying tailings environment. The results demonstrated an explicit depth-dependent differentiation of microbial community composition and function profiles between the surface and deeper tailings layers, paralleling the dramatic shifts in major physical and geochemical properties. Specifically, key genes involved in sulfur and iron oxidation were significantly enriched in the surface tailings, whereas those associated with reductive nitrogen, sulfur, and iron processes were enriched in the deeper layers. Genome-resolved metagenomics retrieved 406 intermediate or high-quality genomes spanning 26 phyla, including major new groups (e.g., Patescibacteria and DPANN). Metabolic models involving nitrogen, sulfur, iron, and carbon cycles were proposed based on the functional potentials of the abundant microbial genomes, emphasizing syntrophy and the importance of lesser-known taxa in the degradation of complex carbon compounds. These results have implications for in situ AMD bioremediation.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Qian Y, Hu L, Wang Y, et al (2023)

Arsenic methylation behavior and microbial regulation mechanisms in landfill leachate saturated zones.

Environmental pollution (Barking, Essex : 1987), 320:121064.

Arsenic (As) is a potential contaminant in landfill. As methylation has been considered as a detoxification mechanism to address this problem. In this study, microcosm incubation was used to simulate leachate saturation zone (LSZ) and other landfill zones scenarios to explore the As methylation behavior. The As methylation rate of LSZ is 11.75%, which is slightly higher than that of other zone of landfill (10.87%). However, the difference was greatly increased by the addition of moderate content of As(III), with values of 29.25% in LSZ and 4.61% in other zones. The microbial community structure varied greatly between zones and a higher abundance of arsM was observed in the LSZ, which enhanced As methylation. Based on the annotated As functional genes from the KEGG database, the microbial As methylated pathway was summarized. Higher relative abundances of gst and arsC promoted the formation of more trivalent As substrates, stimulating the methylation behavior for As detoxification in the LSZ. According to microbial arsM contribution analysis, unclassified_p__Gemmatimonadetes, unclassified_p__Actinobacteria, unclassified_o_Hydrogenophilales, and Intrasporangium were the primary As methylation bacteria in the LSZ, while unclassified_f__Chitinophagaceae and unclassified_c_Gammaproteobacteria were the primary contributors in other landfill zones. These results highlight the specific As methylation process in the LSZ, and these insights could improve the control of As contamination in landfill sites.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Wen C, Pan Y, Gao M, et al (2023)

Altered gut microbiome composition in nontreated plaque psoriasis patients.

Microbial pathogenesis, 175:105970.

Recent studies have demonstrated that dysbiosis of the gut microbiota is associated with psoriasis, but these studies showed some conflicting results. Our study examined differences in microbiome composition associated in people with psoriasis and those without. Comparing individuals with their healthy partners was a second strategy. We explored the fecal microbiota among 32 nontreated plaque psoriasis patients, 15 healthy controls and 17 healthy couples by metagenomic gene sequencing. The relative levels of intestinal microbiota of the psoriasis cohort differed from those in healthy controls and these patients' partners. However, there was no microbial diversity among these three cohorts. On the level of the phylum, Firmicutes and Bacteroidetes' relative abundances were reversed. Escherichia coli was significantly enriched in the psoriasis group compared with the healthy people and the healthy spouses. Gene functional analysis indicated that Ribosome (ko03010) was upregulated, Flagellar assembly (ko02040) and Bacterial chemotaxis (ko02030) were downregulated in the psoriasis cohort compared with the healthy individuals and the healthy spouses. The microbiota in severe psoriasis patients differed from those with milder conditions. These findings strongly support the association between intestinal flora and psoriasis. It is necessary to perform more meaningful experiments to identify whether the differences of gut microbiota are the cause or consequences of psoriasis in future.

RevDate: 2023-02-07
CmpDate: 2023-02-07

He X, Li Z, Li X, et al (2023)

The fecal microbiota of gravidas with fetal growth restriction newborns characterized by metagenomic sequencing.

Current research in translational medicine, 71(1):103354.

BACKGROUND: Fetal growth restriction (FGR) is a complex obstetric complication with various causes and of great harm. However, the specific pathogenesis of FGR is unclear, which limits its effective treatment. Gut microbiota dysbiosis was found to be important in pathogenesis of various diseases. However, its role in FGR development remains unclear and needs to be clarified.

METHODS: In our case-control study, we recruited eight FGR and eight control female participants and collected their fecal samples in third trimester before delivery. We performed metagenomic sequencing and bioinformatic analysis to compare the gut microbiota composition and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between the two groups.

RESULTS: Our results showed that totally 20 gut microbes were significantly different between two groups (p<0•05), and the correlation analysis found that g__Roseomonas and g__unclassified_f__Propionibacteriaceae were significantly positive correlated with both maternal body mass index (BMI) before delivery, placental weight, and neonatal birth weight (BW) percentile (all p<0•05), while g__Marinisporobacter and g__Sphingomonas were significantly negative correlated with both neonatal BMI and neonatal BW percentile (all p<0•05). Through KEGG pathway analysis, we found that the abundance of the Nitrogen metabolism pathway decreased significantly (p<0•05) whereas the abundance of the Amoebiasis pathway increased significantly in the FGR group (p<0•05).

CONCLUSION: In this study, we demonstrated that the occurrence of FGR is associated with the change of gut microbiota of pregnant women.

RevDate: 2023-02-07
CmpDate: 2023-02-07

Su C, Zhou X, Lu P, et al (2023)

Role of coke media strategy in an adsorption-biological coupling technology for wastewater treatment performance, microbial community, and metabolic pathways features.

Environmental science and pollution research international, 30(5):13469-13482.

With the increase of wastewater discharge, the requirement of wastewater treatment technology is gradually increased. How to treat wastewater economically, while making the treatment process short, easy to manage and low running cost, is the focus of attention. Adsorption-biological coupling technology could make adsorption and biodegradation complement each other, which has coupled accumulation effect. In this study, with coke as the adsorbent, the efficiency of the adsorption-biological coupling reactor on the treatment of total phosphorus (TP), chemical oxygen demand (COD), and ammonia nitrogen (NH3-N) in domestic wastewater under different influent modes was investigated. Meanwhile, microbial community and metabolic pathways analysis of the reactor were carried out. Results showed that when the influent modes of the coupling reactor was once a day and the daily sewage treatment capacity was 2 L, the treatment efficiency of TP, COD, and NH3-N was the best. The removal rate of TP and NH3-N was 87.96% and 96.14%, respectively. The dominant phylum was Proteobacteria (39.84-44.49%), and the dominant genus was Sphingomonas (4.27-7.16%), and Gemmatimonas (1.27-3.58%). According to the metagenomic analysis, carbon metabolism process was evenly distributed in U (upper), M (middle), and L (lower) layers of the coupling reactor. Phosphate metabolism was mainly in the U layer at first, then in the M and L layers gradually. Carbon metabolism and phosphate metabolism provided sufficient energy for microbial degradation of pollutants. Nitrogen removal in the reactor mainly happened in the S and Z layers by nitrification (M00528) and denitrification (M00529), respectively.

RevDate: 2023-02-06

Cui W, Li R, Fan Z, et al (2023)

Weak environmental adaptation of rare phylotypes sustaining soil multi-element cycles in response to decades-long fertilization.

The Science of the total environment pii:S0048-9697(23)00679-4 [Epub ahead of print].

Deciphering the ecological role of soil communities in the maintenance of multiple ecosystem functions is pivotal for the conservation and sustainability of soil biodiversity. However, few studies have investigated niche differentiation of abundant and rare microbiota, as well as their contributions to multiple soil elemental cycles, particularly in agroecosystems that have received decades of intense fertilization. Here, we characterized the environmental thresholds and phylogenetic signals for the environmental adaptation of both abundant and rare microbial subcommunities via amplicon sequencing and metagenomic sequencing and explored their importance in sustaining soil multiple nutrient cycling in agricultural fields that were fertilized for two decades. The results showed that rare taxa exhibited narrower niche breadths and weaker phylogenetic signals than abundant species. The assembly of abundant subcommunity was shaped predominantly by dispersal limitation (explained 71.1 % of the variation in bacteria) and undominated processes (explained 75 % of the variation in fungi), whereas the assembly of rare subcommunity was dominated by homogeneous selection process (explained 100 % of the variation in bacteria and 60 % of the variation in fungi). Soil ammonia nitrogen was the leading factor mediating the balance between stochastic and deterministic processes in both abundant (R[2] = 0.15, P < 0.001) and rare (R[2] = 0.08, P < 0.001) bacterial communities. Notably, the rare biosphere largely contributed to key soil processes such as carbon (R[2]bacteria = 0.03, P < 0.05; R[2]fungi = 0.05, P < 0.05) and nitrogen (R[2]bacteria = 0.03, P < 0.05; R[2]fungi = 0.17, P < 0.001) cycling. Collectively, these findings facilitate our understanding of the maintenance of rhizosphere bacterial and fungal diversity in response to agricultural fertilization and highlight the key role of rare taxa in sustaining agricultural ecosystem functions.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Deng K, Xu JJ, Shen L, et al (2023)

Comparison of fecal and blood metabolome reveals inconsistent associations of the gut microbiota with cardiometabolic diseases.

Nature communications, 14(1):571.

Blood metabolome is commonly used in human studies to explore the associations of gut microbiota-derived metabolites with cardiometabolic diseases. Here, in a cohort of 1007 middle-aged and elderly adults with matched fecal metagenomic (149 species and 214 pathways) and paired fecal and blood targeted metabolomics data (132 metabolites), we find disparate associations with taxonomic composition and microbial pathways when using fecal or blood metabolites. For example, we observe that fecal, but not blood butyric acid significantly associates with both gut microbiota and prevalent type 2 diabetes. These findings are replicated in an independent validation cohort involving 103 adults. Our results suggest that caution should be taken when inferring microbiome-cardiometabolic disease associations from either blood or fecal metabolome data.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Satoh S, Tanaka R, Yokono M, et al (2023)

Phylogeny analysis of whole protein-coding genes in metagenomic data detected an environmental gradient for the microbiota.

PloS one, 18(2):e0281288.

Environmental factors affect the growth of microorganisms and therefore alter the composition of microbiota. Correlative analysis of the relationship between metagenomic composition and the environmental gradient can help elucidate key environmental factors and establishment principles for microbial communities. However, a reasonable method to quantitatively compare whole metagenomic data and identify the primary environmental factors for the establishment of microbiota has not been reported so far. In this study, we developed a method to compare whole proteomes deduced from metagenomic shotgun sequencing data, and quantitatively display their phylogenetic relationships as metagenomic trees. We called this method Metagenomic Phylogeny by Average Sequence Similarity (MPASS). We also compared one of the metagenomic trees with dendrograms of environmental factors using a comparison tool for phylogenetic trees. The MPASS method correctly constructed metagenomic trees of simulated metagenomes and soil and water samples. The topology of the metagenomic tree of samples from the Kirishima hot springs area in Japan was highly similarity to that of the dendrograms based on previously reported environmental factors for this area. The topology of the metagenomic tree also reflected the dynamics of microbiota at the taxonomic and functional levels. Our results strongly suggest that MPASS can successfully classify metagenomic shotgun sequencing data based on the similarity of whole protein-coding sequences, and will be useful for the identification of principal environmental factors for the establishment of microbial communities. Custom Perl script for the MPASS pipeline is available at https://github.com/s0sat/MPASS.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Laso-Pérez R, Wu F, Crémière A, et al (2023)

Evolutionary diversification of methanotrophic ANME-1 archaea and their expansive virome.

Nature microbiology, 8(2):231-245.

'Candidatus Methanophagales' (ANME-1) is an order-level clade of archaea responsible for anaerobic methane oxidation in deep-sea sediments. The diversity, ecology and evolution of ANME-1 remain poorly understood. In this study, we use metagenomics on deep-sea hydrothermal samples to expand ANME-1 diversity and uncover the effect of virus-host dynamics. Phylogenetic analyses reveal a deep-branching, thermophilic family, 'Candidatus Methanospirareceae', closely related to short-chain alkane oxidizers. Global phylogeny and near-complete genomes show that hydrogen metabolism within ANME-1 is an ancient trait that was vertically inherited but differentially lost during lineage diversification. Metagenomics also uncovered 16 undescribed virus families so far exclusively targeting ANME-1 archaea, showing unique structural and replicative signatures. The expansive ANME-1 virome contains a metabolic gene repertoire that can influence host ecology and evolution through virus-mediated gene displacement. Our results suggest an evolutionary continuum between anaerobic methane and short-chain alkane oxidizers and underscore the effects of viruses on the dynamics and evolution of methane-driven ecosystems.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Bostancıklıoğlu M, Kaplan DS, Temiz E, et al (2023)

Local myelin damage in the hippocampus fluctuates gut microbiome profile and memory.

Journal of psychiatric research, 158:392-402.

The concept of the gut-brain axis has focused research on how gut dysbiosis affects myelin biology in the brain. However, this axis has not been tested to determine whether it conveys the effects of myelin damage on the gut microbiome profile. Therefore, we aimed to investigate how myelin biology is correlated with gut microbiome profile. The impact of local myelin damage in the hippocampus on gut microbiome profile was investigated with 16S rRNA metagenomic sequence and molecular analysis of myelin biology-associated proteins, and its reflections on memory performance were tested with behavioral tests. Local myelin damage in the hippocampus triggered severe gut dysbiosis, p < .05, changed memory performance, p < .05, and deviated emotional responses. Moreover, myelin treatment with clemastine improved gut dysbiosis and behavioral deviations. Our study provides animal-based evidence on the direct interaction between glial biology in the hippocampus and gut microbiome profile. This study proposes a framework for generating new hypotheses bridging different systems to the gut-brain axis.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Zhang Z, Li J, Jiang S, et al (2023)

Lactobacillus fermentum HNU312 alleviated oxidative damage and behavioural abnormalities during brain development in early life induced by chronic lead exposure.

Ecotoxicology and environmental safety, 251:114543.

Lead exposure is a global public health safety issue that severely disrupts brain development and causes damage to the nervous system in early life. Probiotics and gut microbes have been highlighted for their critical roles in mitigating lead toxicity. However, the underlying mechanisms by which they work yet to be fully explored. Here, we designed a two-stage experiment using the probiotic Lactobacillus fermentum HNU312 (Lf312) to uncover how probiotics alleviate lead toxicity to the brain during early life. First, we explored the tolerance and adsorption of Lf312 to lead in vitro. Second, the adsorption capacity of the strain was determined and confirmed in vivo. The shotgun metagenome sequencing showed lead exposure-induced imbalance and dysfunction of the gut microbiome. In contrast, Lf312 intake significantly modulated the structure of the microbiome, increased the abundance of beneficial bacteria and short-chain fatty acids (SCFAs)-producing bacteria, and upregulated function-related metabolic pathways such as antioxidants. Notably, Lf312 enhanced the integrity of the blood-brain barrier by increasing the levels of SCFAs in the gut, alleviated inflammation in the brain, and ultimately improved anxiety-like and depression-like behaviours induced by lead exposure in mice. Subsequently, the effective mechanism was confirmed, highlighting that Lf312 worked through integrated strategies, including ionic adsorption and microbiota-gut-brain axis regulation. Collectively, this work elucidated the mechanism by which the gut microbiota mitigates the toxic effects of lead in the brain and provides preventive measures and intervention measures for brain damage due to mass lead poisoning in children.

RevDate: 2023-02-06
CmpDate: 2023-02-06

Cheng K, Ning Z, Li L, et al (2023)

MetaLab-MAG: A Metaproteomic Data Analysis Platform for Genome-Level Characterization of Microbiomes from the Metagenome-Assembled Genomes Database.

Journal of proteome research, 22(2):387-398.

The studies of microbial communities have drawn increased attention in various research fields such as agriculture, environment, and human health. Recently, metaproteomics has become a powerful tool to interpret the roles of the community members by investigating the expressed proteins of the microbes. However, analyzing the metaproteomic data sets at genome resolution is still challenging because of the lack of efficient bioinformatics tools. Here we develop MetaLab-MAG, a specially designed tool for the characterization of microbiomes from metagenome-assembled genomes databases. MetaLab-MAG was evaluated by analyzing various human gut microbiota data sets and performed comparably or better than searching the gene catalog protein database directly. MetaLab-MAG can quantify the genome-level microbiota compositions and supports both label-free and isobaric labeling-based quantification strategies. MetaLab-MAG removes the obstacles of metaproteomic data analysis and provides the researchers with in-depth and comprehensive information from the microbiomes.

RevDate: 2023-02-06

Alejandre-Colomo C, Francis B, Viver T, et al (2021)

Cultivable Winogradskyella species are genomically distinct from the sympatric abundant candidate species.

ISME communications, 1(1):51.

Winogradskyella is a genus within the phylum Bacteroidetes with a clear marine origin. Most members of this genus have been found associated with marine animals and algae, but also with inorganic surfaces such as sand. In this study, we analyzed genomes of eleven species recently isolated from surface seawater samples from the North Sea during a single spring algae bloom. Corresponding metagenomes yielded a single Candidatus species for this genus. All species in culture, with the exception of W. ursingii, affiliated with a Winogradskyella lineage characterized by large genomes (~4.3 ± 0.4 Mb), with high complexity in their carbohydrate and protein degradation genes. Specifically, the polysaccharide utilization loci (PULs) were diverse within each individual strain, indicating large substrate versatility. Although present in the North Sea, the abundances of these strains were at, or below, the detection limit of the metagenomes. In contrast, the single species, classified as Candidatus W. atlantica, to which all North Sea MAGs belonged, affiliated with a lineage in which the cultivated representatives showed small genomes of ~3.0-3.5 Mb, with the MAGs having ~2.3 Mb. In Ca. W. atlantica, genome streamlining has apparently resulted in the loss of biosynthesis pathways for several amino acids including arginine, methionine, leucine and valine, and the PUL loci were reduced to a single one for utilizing laminarin. This as-yet uncultivated species seems to capitalize on sporadically abundant substrates that are released by algae blooms, mainly laminarin. We also suggest that this streamlined genome might be responsible for the lack of growth on plates for this Candidatus species, in contrast to growth of the less abundant but coexisting members of the genus.

RevDate: 2023-02-05

Doni L, Oliveri C, Lasa A, et al (2023)

Large-scale impact of the 2016 Marine Heatwave on the plankton-associated microbial communities of the Great Barrier Reef (Australia).

Marine pollution bulletin, 188:114685 pii:S0025-326X(23)00116-9 [Epub ahead of print].

The Great Barrier Reef (GBR) is the world's largest coral ecosystem and is threatened by climate change. This study investigated the impact of the 2016 Marine Heatwave (MHW) on plankton associated microbial communities along a ∼800 km transect in the GBR. 16S rRNA gene metabarcoding of archived plankton samples collected from November 2014 to August 2016 in this region showed a significant increase in Planctomycetes and bacteria belonging to the genus Vibrio and Synechococcus during and after the heatwave. Notably, Droplet Digital PCR and targeted metagenomic analysis applied on samples collected four months after the MHW event revealed the presence of several potential pathogenic Vibrio species previously associated with diseases in aquatic animals. Overall, the 2016 MHW significantly impacted the surface picoplankton community and fostered the spread of potentially pathogenic bacteria across the GBR providing an additional threat for marine biodiversity in this area.

RevDate: 2023-02-03
CmpDate: 2023-02-03

Verburgt CM, Dunn KA, Otley A, et al (2023)

Personalised azithromycin+metronidazole (PAZAZ), in combination with standard induction therapy, to achieve a faecal microbiome community structure and metagenome changes associated with sustained remission in paediatric Crohn's disease (CD): protocol of a pilot study.

BMJ open, 13(2):e064944 pii:bmjopen-2022-064944.

INTRODUCTION: Early relapse in Crohn's disease (CD) is associated with a more severe disease course. The microbiome plays a crucial role, yet strategies targeting the microbiome are underrepresented in current guidelines. We hypothesise that early manipulation of the microbiome will improve clinical response to standard-of-care (SOC) induction therapy in patients with a relapse-associated microbiome profile. We describe the protocol of a pilot study assessing feasibility of treatment allocation based on baseline faecal microbiome profiles.

METHODS AND ANALYSIS: This is a 52-week, multicentre, randomised, controlled, open-label, add-on pilot study to test the feasibility of a larger multicontinent trial evaluating the efficacy of adjuvant antibiotic therapy in 20 paediatric patients with mild-to-moderate-CD (10
ETHICS AND DISSEMINATION: This study was approved by METC-AMC and CCMO (Netherlands) and IWK Health Centre (Canada). The first version of this protocol was approved by North Carolina Children's Hospital (USA), Wolfson Medical Centre (Israel). The FDA (USA), Health Canada and Ministry of Health (Israel) have reviewed and approved the protocol. Results will be published in international peer-reviewed journals and summaries will be provided to the funders and participants.

TRIAL REGISTRATION NUMBER: NCT04186247.

RevDate: 2023-02-03
CmpDate: 2023-02-03

Valles-Colomer M, Blanco-Míguez A, Manghi P, et al (2023)

The person-to-person transmission landscape of the gut and oral microbiomes.

Nature, 614(7946):125-135.

The human microbiome is an integral component of the human body and a co-determinant of several health conditions[1,2]. However, the extent to which interpersonal relations shape the individual genetic makeup of the microbiome and its transmission within and across populations remains largely unknown[3,4]. Here, capitalizing on more than 9,700 human metagenomes and computational strain-level profiling, we detected extensive bacterial strain sharing across individuals (more than 10 million instances) with distinct mother-to-infant, intra-household and intra-population transmission patterns. Mother-to-infant gut microbiome transmission was considerable and stable during infancy (around 50% of the same strains among shared species (strain-sharing rate)) and remained detectable at older ages. By contrast, the transmission of the oral microbiome occurred largely horizontally and was enhanced by the duration of cohabitation. There was substantial strain sharing among cohabiting individuals, with 12% and 32% median strain-sharing rates for the gut and oral microbiomes, and time since cohabitation affected strain sharing more than age or genetics did. Bacterial strain sharing additionally recapitulated host population structures better than species-level profiles did. Finally, distinct taxa appeared as efficient spreaders across transmission modes and were associated with different predicted bacterial phenotypes linked with out-of-host survival capabilities. The extent of microorganism transmission that we describe underscores its relevance in human microbiome studies[5], especially those on non-infectious, microbiome-associated diseases.

RevDate: 2023-02-03
CmpDate: 2023-02-03

Miranda TDS, Schiffler FB, D'arc M, et al (2023)

Metagenomic analysis reveals novel dietary-related viruses in the gut virome of marmosets hybrids (Callithrix jacchus x Callithrix penicillata), Brazil.

Virus research, 325:199017.

Viral metagenomics has contributed enormously to the characterization of a wide range of viruses infecting animals of all phyla in the last decades. Among Neotropical primates, especially those introduced, knowledge about viral diversity remains poorly studied. Therefore, using metagenomics based on virus enrichment, we explored the viral microbiota present in the feces of introduced common marmosets (Callithrix sp.) in three locations from the Silva Jardim region in the State of Rio de Janeiro, Brazil. Fecal samples were collected from nine marmosets, pooled into three sample pools, and sequenced on Illumina MiSeq platform. Sequence reads were analyzed using a viral metagenomic analysis pipeline and two novel insect viruses belonging to the Parvoviridae and Baculoviridae families were identified. The complete genome of a densovirus (Parvoviridae family) of 5,309 nucleotides (nt) was obtained. The NS1 and VP1 proteins share lower than 32% sequence identity with the corresponding proteins of known members of the subfamily Densovirinae. Phylogenetic analysis suggests that this virus represents a new genus, provisionally named Afoambidensovirus due to its discovery in the Brazilian Atlantic Forest. The novel species received the name Afoambidensovirus incertum 1. The complete circular genome of a baculovirus of 107,191 nt was also obtained, showing 60.8% sequence identity with the most closely related member of the Baculoviridae family. Phylogenetic analysis suggests that this virus represents a new species in the Betabaculovirus genus, provisionally named Betabaculovirus incertum 1. In addition, sequences from several families of arthropods in the three pools evaluated were characterized (contigs ranging from 244 to 6,750 nt), corroborating the presence of possible insect hosts with which these new viruses may be associated. Our study expands the knowledge about two viral families known to infect insects, an important component of the marmosets' diet. This identification in hosts' feces samples demonstrates one of the many uses of this type of data and could serve as a basis for future research characterizing viruses in wildlife using noninvasive samples.

RevDate: 2023-02-02

Gendron EM, Sevigny JL, Byiringiro I, et al (2023)

Nematode Mitochondrial Metagenomics - a New Tool for Biodiversity Analysis.

Molecular ecology resources [Epub ahead of print].

DNA barcoding approaches have greatly increased our understanding of biodiversity on the planet, and metabarcoding is widely used for classifying members of the phylum Nematoda. However, loci typically utilized in metabarcoding studies are often unable to resolve closely related species or are unable to recover all taxa present in a sample due to inadequate PCR primer binding. Mitochondrial metagenomics (mtMG) is an alternative approach utilizing shotgun sequencing of total DNA to recover the mitochondrial genomes of all species present in samples. However, this approach requires a comprehensive reference database for identification and currently available mitochondrial sequences for nematodes is highly dominated by sequences from the order Rhabditida and excludes many clades entirely. Here we analyzed the efficacy of mtMG for the recovery of nematode taxa and the generation of mitochondrial genomes. We first developed a curated reference database of nematode mitochondrial sequences and expanded it with 40 newly sequenced taxa. We then tested the mito-metagenomics approach using a series of nematode mock communities consisting of morphologically identified nematode species representing various feeding traits, life stages, and phylogenetic relationships. We were able to identify all but two species through the de novo assembly of COX1 genes. We were also able to recover additional mitochondrial protein coding genes (PCGs) for 23 of the 24 detected species including a full array of 12 PCGs from 5 of the species. We conclude that mtMG offers a potential for the effective recovery of nematode biodiversity but remains limited by the breadth of the reference database.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Kwa WT, Sundarajoo S, Toh KY, et al (2023)

Application of emerging technologies for gut microbiome research.

Singapore medical journal, 64(1):45-52.

Microbiome is associated with a wide range of diseases. The gut microbiome is also a dynamic reflection of health status, which can be modified, thus representing great potential to exploit the mechanisms that influence human physiology. Recent years have seen a dramatic rise in gut microbiome studies, which has been enabled by the rapidly evolving high-throughput sequencing methods (i.e. 16S rRNA sequencing and shotgun sequencing). As the emerging technologies for microbiome research continue to evolve (i.e. metatranscriptomics, metabolomics, culturomics, synthetic biology), microbiome research has moved beyond phylogenetic descriptions and towards mechanistic analyses. In this review, we highlight different approaches to study the microbiome, in particular, the current limitations and future promise of these techniques. This review aims to provide clinicians with a framework for studying the microbiome, as well as to accelerate the adoption of these techniques in clinical practice.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Yang K, Wang X, Hou R, et al (2023)

Rhizosphere phage communities drive soil suppressiveness to bacterial wilt disease.

Microbiome, 11(1):16.

BACKGROUND: Bacterial viruses, phages, play a key role in nutrient turnover and lysis of bacteria in terrestrial ecosystems. While phages are abundant in soils, their effects on plant pathogens and rhizosphere bacterial communities are poorly understood. Here, we used metagenomics and direct experiments to causally test if differences in rhizosphere phage communities could explain variation in soil suppressiveness and bacterial wilt plant disease outcomes by plant-pathogenic Ralstonia solanacearum bacterium. Specifically, we tested two hypotheses: (1) that healthy plants are associated with stronger top-down pathogen control by R. solanacearum-specific phages (i.e. 'primary phages') and (2) that 'secondary phages' that target pathogen-inhibiting bacteria play a stronger role in diseased plant rhizosphere microbiomes by indirectly 'helping' the pathogen.

RESULTS: Using a repeated sampling of tomato rhizosphere soil in the field, we show that healthy plants are associated with distinct phage communities that contain relatively higher abundances of R. solanacearum-specific phages that exert strong top-down pathogen density control. Moreover, 'secondary phages' that targeted pathogen-inhibiting bacteria were more abundant in the diseased plant microbiomes. The roles of R. solanacearum-specific and 'secondary phages' were directly validated in separate greenhouse experiments where we causally show that phages can reduce soil suppressiveness, both directly and indirectly, via top-down control of pathogen densities and by alleviating interference competition between pathogen-inhibiting bacteria and the pathogen.

CONCLUSIONS: Together, our findings demonstrate that soil suppressiveness, which is most often attributed to bacteria, could be driven by rhizosphere phage communities that regulate R. solanacearum densities and strength of interference competition with pathogen-suppressing bacteria. Rhizosphere phage communities are hence likely to be important in determining bacterial wilt disease outcomes and soil suppressiveness in agricultural fields. Video Abstract.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Du Y, Fuhrman JA, F Sun (2023)

ViralCC retrieves complete viral genomes and virus-host pairs from metagenomic Hi-C data.

Nature communications, 14(1):502.

The introduction of high-throughput chromosome conformation capture (Hi-C) into metagenomics enables reconstructing high-quality metagenome-assembled genomes (MAGs) from microbial communities. Despite recent advances in recovering eukaryotic, bacterial, and archaeal genomes using Hi-C contact maps, few of Hi-C-based methods are designed to retrieve viral genomes. Here we introduce ViralCC, a publicly available tool to recover complete viral genomes and detect virus-host pairs using Hi-C data. Compared to other Hi-C-based methods, ViralCC leverages the virus-host proximity structure as a complementary information source for the Hi-C interactions. Using mock and real metagenomic Hi-C datasets from several different microbial ecosystems, including the human gut, cow fecal, and wastewater, we demonstrate that ViralCC outperforms existing Hi-C-based binning methods as well as state-of-the-art tools specifically dedicated to metagenomic viral binning. ViralCC can also reveal the taxonomic structure of viruses and virus-host pairs in microbial communities. When applied to a real wastewater metagenomic Hi-C dataset, ViralCC constructs a phage-host network, which is further validated using CRISPR spacer analyses. ViralCC is an open-source pipeline available at https://github.com/dyxstat/ViralCC .

RevDate: 2023-02-02
CmpDate: 2023-02-02

Distaso M, Cea-Rama I, Coscolín C, et al (2023)

The Mobility of the Cap Domain Is Essential for the Substrate Promiscuity of a Family IV Esterase from Sorghum Rhizosphere Microbiome.

Applied and environmental microbiology, 89(1):e0180722.

Metagenomics offers the possibility to screen for versatile biocatalysts. In this study, the microbial community of the Sorghum bicolor rhizosphere was spiked with technical cashew nut shell liquid, and after incubation, the environmental DNA (eDNA) was extracted and subsequently used to build a metagenomic library. We report the biochemical features and crystal structure of a novel esterase from the family IV, EH0, retrieved from an uncultured sphingomonad after a functional screen in tributyrin agar plates. EH0 (optimum temperature [Topt], 50°C; melting temperature [Tm], 55.7°C; optimum pH [pHopt], 9.5) was stable in the presence of 10 to 20% (vol/vol) organic solvents and exhibited hydrolytic activity against p-nitrophenyl esters from acetate to palmitate, preferably butyrate (496 U mg[-1]), and a large battery of 69 structurally different esters (up to 30.2 U mg[-1]), including bis(2-hydroxyethyl)-terephthalate (0.16 ± 0.06 U mg[-1]). This broad substrate specificity contrasts with the fact that EH0 showed a long and narrow catalytic tunnel, whose access appears to be hindered by a tight folding of its cap domain. We propose that this cap domain is a highly flexible structure whose opening is mediated by unique structural elements, one of which is the presence of two contiguous proline residues likely acting as possible hinges, which together allow for the entrance of the substrates. Therefore, this work provides a new role for the cap domain, which until now was thought to be an immobile element that contained hydrophobic patches involved in substrate prerecognition and in turn substrate specificity within family IV esterases. IMPORTANCE A better understanding of structure-function relationships of enzymes allows revelation of key structural motifs or elements. Here, we studied the structural basis of the substrate promiscuity of EH0, a family IV esterase, isolated from a sample of the Sorghum bicolor rhizosphere microbiome exposed to technical cashew nut shell liquid. The analysis of EH0 revealed the potential of the sorghum rhizosphere microbiome as a source of enzymes with interesting properties, such as pH and solvent tolerance and remarkably broad substrate promiscuity. Its structure resembled those of homologous proteins from mesophilic Parvibaculum and Erythrobacter spp. and hyperthermophilic Pyrobaculum and Sulfolobus spp. and had a very narrow, single-entry access tunnel to the active site, with access controlled by a capping domain that includes a number of nonconserved proline residues. These structural markers, distinct from those of other substrate-promiscuous esterases, can help in tuning substrate profiles beyond tunnel and active site engineering.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Lv Y, Lou Y, Liu A, et al (2023)

The impact of exclusive enteral nutrition on the gut microbiome and bile acid metabolism in pediatric Crohn's disease.

Clinical nutrition (Edinburgh, Scotland), 42(2):116-128.

BACKGROUND: Gut dysbiosis and associated bile acid (BA) metabolism play an important role in the pathogenesis of Crohn's disease (CD). We investigated the impacts of the exclusive enteral nutrition treatment (EEN) on the gut microbiome (GM) and BAs metabolism for patients with CD.

METHODS: Targeted metabolomics analysis and metagenomics analysis were performed in feces to investigate the BA and GM changes of patients before and after 2-months EEN therapy. The Pediatric Crohn's Disease Activity Index (PCDAI) and fecal calprotectin were used to evaluate the severity and mucosal inflammation of CD.

RESULTS: A total of 27 newly diagnosed pediatric patients with CD and 27 healthy controls were recruited in this study. Both GM structure and the secondary BA metabolism were significantly impaired in patients, which could return towards normal levels after EEN treatment. The most abundant taxa Firmicutes and 11 BAs were found closely associated with the PCDAI score and fecal calprotectin. Meanwhile, the close interactions between Firmicute bacteria and BAs might contribute to the remission of CD after EEN treatment. The qPCR data further confirmed that the relative expressions of Firmicutes phylum, and genus Flavonifractor and Clostridium V were improved after EEN treatment.

CONCLUSIONS: Firmicutes bacteria and the balance of primary and secondary BA compositions in the gut were closely associated with the health status of CD disease indicated by the PCDAI score and fecal calprotectin. Understanding the recovery process of gut microbiome and BA metabolism will help us to explore the potential mechanisms of EEN therapy.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Hellmann J, Ta A, Ollberding NJ, et al (2023)

Patient-Reported Outcomes Correlate With Microbial Community Composition Independent of Mucosal Inflammation in Pediatric Inflammatory Bowel Disease.

Inflammatory bowel diseases, 29(2):286-296.

BACKGROUND: Inflammatory bowel diseases (IBDs) involve an aberrant host response to intestinal microbiota causing mucosal inflammation and gastrointestinal symptoms. Patient-reported outcomes (PROs) are increasingly important in clinical care and research. Our aim was to examine associations between PROs and fecal microbiota in patients 0 to 22 years of age with IBD.

METHODS: A longitudinal, prospective, single-center study tested for associations between microbial community composition via shotgun metagenomics and PROs including stool frequency and rectal bleeding in ulcerative colitis (UC) and abdominal pain and stool frequency in Crohn's disease (CD). Mucosal inflammation was assessed with fecal calprotectin. A negative binomial mixed-effects model including clinical characteristics and fecal calprotectin tested for differentially abundant species and metabolic pathways by PROs.

RESULTS: In 70 CD patients with 244 stool samples, abdominal pain correlated with increased relative abundance of Haemophilus and reduced Clostridium spp. There were no differences relative to calprotectin level. In 23 UC patients with 76 samples, both rectal bleeding and increased stool frequency correlated with increased Klebsiella and reduced Bacteroides spp. Conversely, UC patients with lower calprotectin had reduced Klebsiella. Both UC and CD patients with active symptoms exhibited less longitudinal microbial community stability. No differences in metabolic pathways were observed in CD. Increased sulfoglycolysis and ornithine biosynthesis correlated with symptomatic UC.

CONCLUSIONS: Microbial community composition correlated with PROs in both CD and UC. Metabolic pathways differed relative to PROs in UC, but not CD. Data suggest that microbiota may contribute to patient symptoms in IBD, in addition to effects of mucosal inflammation.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Van Rossum T, Costea PI, Paoli L, et al (2022)

metaSNV v2: detection of SNVs and subspecies in prokaryotic metagenomes.

Bioinformatics (Oxford, England), 38(4):1162-1164.

SUMMARY: Taxonomic analysis of microbial communities is well supported at the level of species and strains. However, species can contain significant phenotypic diversity and strains are rarely widely shared across global populations. Stratifying the diversity between species and strains can identify 'subspecies', which are a useful intermediary. High-throughput identification and profiling of subspecies is not yet supported in the microbiome field. Here, we use an operational definition of subspecies based on single nucleotide variant (SNV) patterns within species to identify and profile subspecies in metagenomes, along with their distinctive SNVs and genes. We incorporate this method into metaSNV v2, which extends existing SNV-calling software to support further SNV interpretation for population genetics. These new features support microbiome analyses to link SNV profiles with host phenotype or environment and niche-specificity. We demonstrate subspecies identification in marine and fecal metagenomes. In the latter, we analyze 70 species in 7524 adult and infant subjects, supporting a common subspecies population structure in the human gut microbiome and illustrating some limits in subspecies calling.

Source code, documentation, tutorials and test data are available at https://github.com/metasnv-tool/metaSNV and https://metasnv.embl.de.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Gordon-Rodriguez E, Quinn TP, JP Cunningham (2021)

Learning sparse log-ratios for high-throughput sequencing data.

Bioinformatics (Oxford, England), 38(1):157-163.

MOTIVATION: The automatic discovery of sparse biomarkers that are associated with an outcome of interest is a central goal of bioinformatics. In the context of high-throughput sequencing (HTS) data, and compositional data (CoDa) more generally, an important class of biomarkers are the log-ratios between the input variables. However, identifying predictive log-ratio biomarkers from HTS data is a combinatorial optimization problem, which is computationally challenging. Existing methods are slow to run and scale poorly with the dimension of the input, which has limited their application to low- and moderate-dimensional metagenomic datasets.

RESULTS: Building on recent advances from the field of deep learning, we present CoDaCoRe, a novel learning algorithm that identifies sparse, interpretable and predictive log-ratio biomarkers. Our algorithm exploits a continuous relaxation to approximate the underlying combinatorial optimization problem. This relaxation can then be optimized efficiently using the modern ML toolbox, in particular, gradient descent. As a result, CoDaCoRe runs several orders of magnitude faster than competing methods, all while achieving state-of-the-art performance in terms of predictive accuracy and sparsity. We verify the outperformance of CoDaCoRe across a wide range of microbiome, metabolite and microRNA benchmark datasets, as well as a particularly high-dimensional dataset that is outright computationally intractable for existing sparse log-ratio selection methods.

The CoDaCoRe package is available at https://github.com/egr95/R-codacore. Code and instructions for reproducing our results are available at https://github.com/cunningham-lab/codacore.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-02-02
CmpDate: 2023-02-02

Salazar G, Ruscheweyh HJ, Hildebrand F, et al (2021)

mTAGs: taxonomic profiling using degenerate consensus reference sequences of ribosomal RNA genes.

Bioinformatics (Oxford, England), 38(1):270-272.

UNLABELLED: Profiling the taxonomic composition of microbial communities commonly involves the classification of ribosomal RNA gene fragments. As a trade-off to maintain high classification accuracy, existing tools are typically limited to the genus level. Here, we present mTAGs, a taxonomic profiling tool that implements the alignment of metagenomic sequencing reads to degenerate consensus reference sequences of small subunit ribosomal RNA genes. It uses DNA fragments, that is, paired-end sequencing reads, as count units and provides relative abundance profiles at multiple taxonomic ranks, including operational taxonomic units based on a 97% sequence identity cutoff. At the genus rank, mTAGs outperformed other tools across several metrics, such as the F1 score by >11% across data from different environments, and achieved competitive (F1 score) or better results (Bray-Curtis dissimilarity) at the sub-genus level.

The software tool mTAGs is implemented in Python. The source code and binaries are freely available (https://github.com/SushiLab/mTAGs). The data underlying this article are available in Zenodo, at https://doi.org/10.5281/zenodo.4352762.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-02-01

Ngugi DK, Salcher MM, Andrei AS, et al (2023)

Postglacial adaptations enabled colonization and quasi-clonal dispersal of ammonia-oxidizing archaea in modern European large lakes.

Science advances, 9(5):eadc9392.

Ammonia-oxidizing archaea (AOA) play a key role in the aquatic nitrogen cycle. Their genetic diversity is viewed as the outcome of evolutionary processes that shaped ancestral transition from terrestrial to marine habitats. However, current genome-wide insights into AOA evolution rarely consider brackish and freshwater representatives or provide their divergence timeline in lacustrine systems. An unbiased global assessment of lacustrine AOA diversity is critical for understanding their origins, dispersal mechanisms, and ecosystem roles. Here, we leveraged continental-scale metagenomics to document that AOA species diversity in freshwater systems is remarkably low compared to marine environments. We show that the uncultured freshwater AOA, "Candidatus Nitrosopumilus limneticus," is ubiquitous and genotypically static in various large European lakes where it evolved 13 million years ago. We find that extensive proteome remodeling was a key innovation for freshwater colonization of AOA. These findings reveal the genetic diversity and adaptive mechanisms of a keystone species that has survived clonally in lakes for millennia.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Champion C, Neagoe RM, Effernberger M, et al (2023)

Human liver microbiota modeling strategy at the early onset of fibrosis.

BMC microbiology, 23(1):34.

BACKGROUND: Gut microbiota is involved in the development of liver diseases such as fibrosis. We and others identified that selected sets of gut bacterial DNA and bacteria translocate to tissues, notably the liver, to establish a non-infectious tissue microbiota composed of microbial DNA and a low frequency live bacteria. However, the precise set of bacterial DNA, and thereby the corresponding taxa associated with the early stages of fibrosis need to be identified. Furthermore, to overcome the impact of different group size and patient origins we adapted innovative statistical approaches. Liver samples with low liver fibrosis scores (F0, F1, F2), to study the early stages of the disease, were collected from Romania(n = 36), Austria(n = 10), Italy(n = 19), and Spain(n = 17). The 16S rRNA gene was sequenced. We considered the frequency, sparsity, unbalanced sample size between cohorts to identify taxonomic profiles and statistical differences.

RESULTS: Multivariate analyses, including adapted spectral clustering with L1-penalty fair-discriminant strategies, and predicted metagenomics were used to identify that 50% of liver taxa associated with the early stage fibrosis were Enterobacteriaceae, Pseudomonadaceae, Xanthobacteriaceae and Burkholderiaceae. The Flavobacteriaceae and Xanthobacteriaceae discriminated between F0 and F1. Predicted metagenomics analysis identified that the preQ0 biosynthesis and the potential pathways involving glucoryranose and glycogen degradation were negatively associated with liver fibrosis F1-F2 vs F0.

CONCLUSIONS: Without demonstrating causality, our results suggest first a role of bacterial translocation to the liver in the progression of fibrosis, notably at the earliest stages. Second, our statistical approach can identify microbial signatures and overcome issues regarding sample size differences, the impact of environment, and sets of analyses.

TRIAL REGISTRATION: TirguMECCH ROLIVER Prospective Cohort for the Identification of Liver Microbiota, registration 4065/2014. Registered 01 01 2014.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Yu Y, Yu X, Zhang D, et al (2023)

Biotransformation of Organophosphate Esters by Rice and Rhizosphere Microbiome: Multiple Metabolic Pathways, Mechanism, and Toxicity Assessment.

Environmental science & technology, 57(4):1776-1787.

The biotransformation behavior and toxicity of organophosphate esters (OPEs) in rice and rhizosphere microbiomes were comprehensively studied by hydroponic experiments. OPEs with lower hydrophobicity were liable to be translocated acropetally, and rhizosphere microbiome could reduce the uptake and translocation of OPEs in rice tissues. New metabolites were successfully identified in rice and rhizosphere microbiome, including hydrolysis, hydroxylated, methylated, and glutathione-, glucuronide-, and sulfate-conjugated products. Rhizobacteria and plants could cooperate to form a complex ecological interaction web for OPE elimination. Furthermore, active members of the rhizosphere microbiome during OPE degradation were revealed and the metagenomic analysis indicated that most of these active populations contained OPE-degrading genes. The results of metabolomics analyses for phytotoxicity assessment implied that several key function metabolic pathways of the rice plant were found perturbed by metabolites, such as diphenyl phosphate and monophenyl phosphate. In addition, the involved metabolism mechanisms, such as the carbohydrate metabolism, amino acid metabolism and synthesis, and nucleotide metabolism in Escherichia coli, were significantly altered after exposure to the products mixture of OPEs generated by rhizosphere microbiome. This work for the first time gives a comprehensive understanding of the entire metabolism of OPEs in plants and associated microbiome, and provides support for the ongoing risk assessment of emerging contaminants and, most critically, their transformation products.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Alvarenga BO, Paiva JB, Souza AIS, et al (2023)

Metagenomics analysis of the morphological aspects and bacterial composition of broiler feces.

Poultry science, 102(2):102401.

In this descriptive study, we used metagenomics to analyze the relationship between the morphological aspects of chicken feces and its respective bacterial compositions. The microbiota composition was determined by sequencing the V4 region of the 16S rRNA genes collected from fresh broiler feces at 19 d old. In total, 48 samples were collected and divided into 8 groups of 6 samples each. The morphological changes studied were feed passage (FP) and reddish mucus (RM). Each was classified into 3 levels of intensity: 1 (slight), 2 (moderate), or 3 (intense). Thus, the 8 groups studied were feed passage (FP-1; FP-2; FP-3), reddish mucus (RM-1; RM-2; RM-3), normal ileal feces (NIF), and cecal discharge (CD). The alpha diversity (Shannon's index) revealed that the CD group showed greater diversity, and was significantly different from FP-2, FP-3, and RM-1. The beta diversity showed that the CD group samples were more homogeneous than the ileal feces groups. The relative abundance analysis revealed that Firmicutes and Proteobacteria were the most abundant phyla in the ileal feces groups. In CD, Firmicutes and Bacteroidetes were the most abundant. The relative abundance at the genus level revealed 136 different bacterial genera. In the ileal feces groups, the two most abundant genera were Lactobacillus and Escherichia/Shigella, except in the FP-1 and RM-2 groups, which had the opposite order. Unlike the others, the CD group had a higher abundance of Bacteroides and Faecalibacterium. When comparing the NIF group with the others, significant changes were found in the fecal microbiota, with nine genera for the FP groups, 19 for the RM groups, and 61 when compared to CD. The results of the present study suggest that evaluation of fecal morphology is a fundamental task that makes it possible to act quickly and assertively, as the morphological aspects of the feces may be related to the composition and structure of fecal microbiota.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Jan TR, Lin CS, Wang SY, et al (2023)

Cytokines and cecal microbiome modulations conferred by a dual vaccine in Salmonella-infected layers.

Poultry science, 102(2):102373.

Zoonotic Salmonella infection is a critical and challenging issue for public health. Since human infections are mainly associated with consuming contaminated chicken products, strategies to reduce Salmonella carriage and shedding are essential. Here we investigate the mechanisms of the live attenuated Salmonella vaccine (AviPro Salmonella Duo) against Salmonella Enteritidis (SE) infection. We focused on inflammatory-related cytokine expressions and cecal microbiota modulations in specific-pathogen-free (SPF) and field layers. Forty-eight 2-day-old SPF layers were randomly allotted into S.SEvc, S.SEc, S.Vc, and S.Ct groups in trial 1. The equal number of filed layers at 25 wk were allocated into SEvc, SEc, Vc, and Ct groups in trial 2. Each group contained 12 layers. Groups were further assigned for vaccination (S.Vc and Vc groups), SE challenge (S.SEc and SEc groups), vaccination and the following SE challenge (S.SEvc and SEvc groups), or the placebo treatment (S.Ct and Ct groups). Cecal tissues and contents of layers on day 14 post-SE-challenges were collected for cytokine mRNA expression and 16S rRNA metagenomic analyses. We found that SE challenges significantly upregulated expressions of IFNγ, IL-1β, IL-12β, and NFκB1A in SPF layers. The vaccine notably counteracted the levels of IFNα, IFNγ, and NFκB1A activated by SE attacks. The vaccination, SE challenge, and their combination did not significantly affect alpha diversities but promoted dissimilarities in microbial communities between groups. Eubacterium_coprostanoligenes and Faecalibacterium_prausnitzii were identified as contributory taxa in the cecal microbiota of SE-challenged and vaccinated SPF layers. A significantly higher abundance of Faecalibacterium_prausnitzii in the ceca further correlated with the vaccination conferred protection against SE infection. In contrast, Oscillibacter_valericigenes and Mediterraneibacter_glycyrrhizinilyticus were featured taxa in Salmonella-infected field layers. Megamonas_hypermegale and Megamonas_rupellensis were identified as featured taxa in vaccinated field layers compared to SE-infected layers. To conclude, applying a dual Salmonella vaccine in this study modulated expressions of inflammatory-related cytokines and the cecal microbiome in layers, contributing to protection against SE infection. The feature microbes are promising for developing predictive indices and as antibiotic alternatives added to feed to reduce the risk of Salmonella shedding and contamination.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Du H, Chen B, Fu W, et al (2023)

Composition and function of viruses in sauce-flavor baijiu fermentation.

International journal of food microbiology, 387:110055.

Viruses are highly abundant in nature, associated with quality and safety of traditional fermented foods. However, the overall viral diversity and function are still poorly understood in food microbiome. Traditional baijiu fermentation is an ideal model system to examine the diversity and function of viruses owing to easy access, stable operation, and domesticated microbial community. Equipped with cutting-edge viral metagenomics, we investigated the viral community in the fermented grain and fermentation environment, as well as their contribution to baijiu fermentation. Viral communities in the fermented grains and fermentation environment are highly similar. The dominant viruses were bacteriophages, mainly including the order Caudovirales and the family Inoviridae. Furtherly, association network analysis showed that viruses and bacteria were significantly negatively correlated (P < 0.01). Viral diversity could significantly influence bacterial and fungal succession (P < 0.05). Moreover, we proved that starter phages could significantly inhibit the growth of Bacillus licheniformis in the logarithmic growth stage (P < 0.05) under culture condition. Based on the functional annotations, viruses and bacteria both showed high distribution of genes related to amino acid and carbohydrate metabolism. In addition, abundant auxiliary carbohydrate-active enzyme (CAZyme) genes were also identified in viruses, indicating that viruses were involved in the decomposition of complex polysaccharides during fermentation. Our results revealed that viruses could crucially affect microbial community and metabolism during traditional fermentation.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Fan L, Chen J, Pan L, et al (2023)

Alterations of Gut Microbiome, Metabolome, and Lipidome in Takayasu Arteritis.

Arthritis & rheumatology (Hoboken, N.J.), 75(2):266-278.

OBJECTIVE: Mounting evidence has linked microbiome and metabolome to systemic autoimmunity and cardiovascular diseases (CVDs). Takayasu arteritis (TAK) is a rare disease that shares features of immune-related inflammatory diseases and CVDs, about which there is relatively limited information. This study was undertaken to characterize gut microbial dysbiosis and its crosstalk with phenotypes in TAK.

METHODS: To address the discriminatory signatures, we performed shotgun sequencing of fecal metagenome across a discovery cohort (n = 97) and an independent validation cohort (n = 75) including TAK patients, healthy controls, and controls with Behçet's disease (BD). Interrogation of untargeted metabolomics and lipidomics profiling of plasma and fecal samples were also used to refine features mediating associations between microorganisms and TAK phenotypes.

RESULTS: A combined model of bacterial species, including unclassified Escherichia, Veillonella parvula, Streptococcus parasanguinis, Dorea formicigenerans, Bifidobacterium adolescentis, Lachnospiraceae bacterium 7 1 58FAA, Escherichia coli, Streptococcus salivarius, Klebsiella pneumoniae, Bifidobacterium longum, and Lachnospiraceae Bacterium 5 1 63FAA, distinguished TAK patients from controls with areas under the curve (AUCs) of 87.8%, 85.9%, 81.1%, and 71.1% in training, test, and validation sets including healthy or BD controls, respectively. Diagnostic species were directly or indirectly (via metabolites or lipids) correlated with TAK phenotypes of vascular involvement, inflammation, discharge medication, and prognosis. External validation against publicly metagenomic studies (n = 184) on hypertension, atrial fibrillation, and healthy controls, confirmed the diagnostic accuracy of the model for TAK.

CONCLUSION: This study first identifies the discriminatory gut microbes in TAK. Dysbiotic microbes are also linked to TAK phenotypes directly or indirectly via metabolic and lipid modules. Further explorations of the microbiome-metagenome interface in TAK subtype prediction and pathogenesis are suggested.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Arisdakessian CG, Nigro OD, Steward GF, et al (2021)

CoCoNet: an efficient deep learning tool for viral metagenome binning.

Bioinformatics (Oxford, England), 37(18):2803-2810.

MOTIVATION: Metagenomic approaches hold the potential to characterize microbial communities and unravel the intricate link between the microbiome and biological processes. Assembly is one of the most critical steps in metagenomics experiments. It consists of transforming overlapping DNA sequencing reads into sufficiently accurate representations of the community's genomes. This process is computationally difficult and commonly results in genomes fragmented across many contigs. Computational binning methods are used to mitigate fragmentation by partitioning contigs based on their sequence composition, abundance or chromosome organization into bins representing the community's genomes. Existing binning methods have been principally tuned for bacterial genomes and do not perform favorably on viral metagenomes.

RESULTS: We propose Composition and Coverage Network (CoCoNet), a new binning method for viral metagenomes that leverages the flexibility and the effectiveness of deep learning to model the co-occurrence of contigs belonging to the same viral genome and provide a rigorous framework for binning viral contigs. Our results show that CoCoNet substantially outperforms existing binning methods on viral datasets.

CoCoNet was implemented in Python and is available for download on PyPi (https://pypi.org/). The source code is hosted on GitHub at https://github.com/Puumanamana/CoCoNet and the documentation is available at https://coconet.readthedocs.io/en/latest/index.html. CoCoNet does not require extensive resources to run. For example, binning 100k contigs took about 4 h on 10 Intel CPU Cores (2.4 GHz), with a memory peak at 27 GB (see Supplementary Fig. S9). To process a large dataset, CoCoNet may need to be run on a high RAM capacity server. Such servers are typically available in high-performance or cloud computing settings.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-02-01
CmpDate: 2023-02-01

Commichaux S, Shah N, Ghurye J, et al (2021)

A critical assessment of gene catalogs for metagenomic analysis.

Bioinformatics (Oxford, England), 37(18):2848-2857.

MOTIVATION: Microbial gene catalogs are data structures that organize genes found in microbial communities, providing a reference for standardized analysis of the microbes across samples and studies. Although gene catalogs are commonly used, they have not been critically evaluated for their effectiveness as a basis for metagenomic analyses.

RESULTS: As a case study, we investigate one such catalog, the Integrated Gene Catalog (IGC), however, our observations apply broadly to most gene catalogs constructed to date. We focus on both the approach used to construct this catalog and on its effectiveness when used as a reference for microbiome studies. Our results highlight important limitations of the approach used to construct the IGC and call into question the broad usefulness of gene catalogs more generally. We also recommend best practices for the construction and use of gene catalogs in microbiome studies and highlight opportunities for future research.

All supporting scripts for our analyses can be found on GitHub: https://github.com/SethCommichaux/IGC.git. The supporting data can be downloaded from: https://obj.umiacs.umd.edu/igc-analysis/IGC_analysis_data.tar.gz.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-01-31
CmpDate: 2023-01-31

Chen C, Yan Q, Yao X, et al (2022)

Alterations of the gut virome in patients with systemic lupus erythematosus.

Frontiers in immunology, 13:1050895.

BACKGROUND: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that has been linked to the dysbiosis of the gut microbiome and virome. However, the potential characterization of the gut virome in SLE patients needs to be explored more extensively.

METHODS: Herein, we analyzed the gut viral community of 16 SLE patients and 31 healthy controls using both bulk and virus-like particle (VLP)-based metagenomic sequencing of their fecal samples. A total of 15,999 non-redundant viral operational taxonomic units (vOTUs) were identified from the metagenomic assembled contigs and used for gut virome profiling.

RESULTS: SLE patients exhibited a significant decrease in gut viral diversity in the bulk metagenome dataset, but this change was not significant in the VLP metagenome dataset. Also, considerable alterations of the overall gut virome composition and remarkable changes in the viral family compositions were observed in SLE patients compared with healthy controls, as observed in both two technologies. We identified 408 vOTUs (177 SLE-enriched and 231 control-enriched) with significantly different relative abundances between patients and controls in the bulk virome, and 18 vOTUs (17 SLE-enriched in 1 control-enriched) in the VLP virome. The SLE-enriched vOTUs included numerous Siphoviridae, Microviridae, and crAss-like viruses and were frequently predicted to infect Bacteroides, Parabacteroides, and Ruminococcus_E, while the control-enriched contained numerous members of Siphoviridae and Myoviridae and were predicted to infect Prevotella and Lachnospirales_CAG-274. We explored the correlations between gut viruses and bacteria and found that some Lachnospirales_CAG-274 and Hungatella_A phages may play key roles in the virus-bacterium network. Furthermore, we explored the gut viral signatures for disease discrimination and achieved an area under the receiver operator characteristic curve (AUC) of above 0.95, suggesting the potential of the gut virome in the prediction of SLE.

CONCLUSION: Our findings demonstrated the alterations in viral diversity and taxonomic composition of the gut virome of SLE patients. Further research into the etiology of SLE and the gut viral community will open up new avenues for treating and preventing SLE and other autoimmune diseases.

RevDate: 2023-01-31
CmpDate: 2023-01-31

Xiao QY, Ye TY, Wang XL, et al (2022)

Effects of Qi-Fu-Yin on aging of APP/PS1 transgenic mice by regulating the intestinal microbiome.

Frontiers in cellular and infection microbiology, 12:1048513.

INTRODUCTION: Alzheimer's disease is the most common form of dementia and closely related to aging. Qi-Fu-Yin is widely used to treat dementia, but its anti-aging effects is unknown.

METHODS: We used 11-month-old APP/PS1 transgenic mice for behavioral tests to observe the changes in cognitive function and age-related symptoms after Qi-Fu-Yin treatment. Fecal samples were collected for 16sRNA sequencing and metagenomic sequencing. Differences among the groups of intestinal microbiota and the associations with aging and intestinal microbiota were analyzed based on the results.

RESULTS: Here we found that Qi-Fu-Yin improved the ability of motor coordination, raised survival rate and prolonged the survival days under cold stress stimulation in aged APP/ PS1 transgenic mice. Our data from 16sRNA and metagenomic sequencing showed that at the Family level, the intestinal microbiota was significantly different among wild-type mice, APP/PS1 transgenic mice and the Qi-Fu-Yin group by PCA analysis. Importantly, Qi-Fu-Yin improved the functional diversity of the major KEGG pathways, carbohydrate-active enzymes, and major virulence factors in the intestinal flora of APP/PS1 transgenic mice. Among them, the functions of eight carbohydrate-active enzymes (GT2_Glycos_transf_2, GT4, GT41, GH2, CE1, CE10, CE3, and GH24) and the functions of top three virulence factors (defensive virulence factors, offensive virulence factors and nonspecific virulence factors) were significantly and positively correlated with the level of grasping ability. We further indicated that the Qi-Fu-Yin significantly reduced the plasma levels of IL-6.

CONCLUSION: Our results indicated that the effects of Qi-Fu-Yin anti-aging of APP/PS1 transgenic mice might be through the regulation of intestinal flora diversity, species richness and the function of major active enzymes.

RevDate: 2023-01-31
CmpDate: 2023-01-31

Pantoja-Feliciano IG, Karl JP, Perisin M, et al (2023)

In vitro gut microbiome response to carbohydrate supplementation is acutely affected by a sudden change in diet.

BMC microbiology, 23(1):32.

BACKGROUND: Interactions between diet, stress and the gut microbiome are of interest as a means to modulate health and performance. Here, in vitro fermentation was used to explore the effects of a sudden change in diet, 21 days sole sustenance on the Meal, Ready-to-Eat (MRE) U.S. military combat ration, on inter-species competition and functional potential of the human gut microbiota. Human fecal samples collected before and after MRE intervention or consuming a habitual diet (HAB) were introduced to nutrient-rich media supplemented with starch for in vitro fermentation under ascending colon conditions. 16S rRNA amplicon and Whole-metagenome sequencing (WMS) were used to measure community composition and functional potential. Specific statistical analyses were implemented to detect changes in relative abundance from taxa, genes and pathways.

RESULTS: Differential changes in relative abundance of 11 taxa, Dorea, Lachnospira, Bacteroides fragilis, Akkermansia muciniphila, Bifidobacterium adolescentis, Betaproteobacteria, Enterobacteriaceae, Bacteroides egerthii, Ruminococcus bromii, Prevotella, and Slackia, and nine Carbohydrate-Active Enzymes, specifically GH13_14, over the 24 h fermentation were observed as a function of the diet intervention and correlated to specific taxa of interest.

CONCLUSIONS: These findings suggest that consuming MRE for 21 days acutely effects changes in gut microbiota structure in response to carbohydrate but may induce alterations in metabolic capacity. Additionally, these findings demonstrate the potential of starch as a candidate supplemental strategy to functionally modulate specific gut commensals during stress-induced states.

RevDate: 2023-01-31
CmpDate: 2023-01-31

Kim H, Kim ES, Cho JH, et al (2023)

Exploring the Microbial Community and Functional Characteristics of the Livestock Feces Using the Whole Metagenome Shotgun Sequencing.

Journal of microbiology and biotechnology, 33(1):51-60.

The foodborne illness is the important public health concerns, and the livestock feces are known to be one of the major reservoirs of foodborne pathogens. Also, it was reported that 45.5% of foodborne illness outbreaks have been associated with the animal products contaminated with the livestock feces. In addition, it has been known that the persistence of a pathogens depends on many potential virulent factors including the various virulent genes. Therefore, the first step to understanding the public health risk of livestock feces is to identify and describe microbial communities and potential virulent genes that contribute to bacterial pathogenicity. We used the whole metagenome shotgun sequencing to evaluate the prevalence of foodborne pathogens and to characterize the virulence associated genes in pig and chicken feces. Our data showed that the relative abundance of potential foodborne pathogens, such as Bacillus cereus was higher in chickens than pigs at the species level while the relative abundance of foodborne pathogens including Campylobacter coli was only detected in pigs. Also, the microbial functional characteristics of livestock feces revealed that the gene families related to "Biofilm formation and quorum sensing" were highly enriched in pigs than chicken. Moreover, the variety of gene families associated with "Resistance to antibiotics and toxic compounds" were detected in both animals. These results will help us to prepare the scientific action plans to improve awareness and understanding of the public health risks of livestock feces.

RevDate: 2023-01-30

Busi SB, de Nies L, Habier J, et al (2021)

Persistence of birth mode-dependent effects on gut microbiome composition, immune system stimulation and antimicrobial resistance during the first year of life.

ISME communications, 1(1):8.

Caesarean section delivery (CSD) disrupts mother-to-neonate transmission of specific microbial strains and functional repertoires as well as linked immune system priming. Here we investigate whether differences in microbiome composition and impacts on host physiology persist at 1 year of age. We perform high-resolution, quantitative metagenomic analyses of the gut microbiomes of infants born by vaginal delivery (VD) or by CSD, from immediately after birth through to 1 year of life. Several microbial populations show distinct enrichments in CSD-born infants at 1 year of age including strains of Bacteroides caccae, Bifidobacterium bifidum and Ruminococcus gnavus, whereas others are present at higher levels in the VD group including Faecalibacterium prausnitizii, Bifidobacterium breve and Bifidobacterium kashiwanohense. The stimulation of healthy donor-derived primary human immune cells with LPS isolated from neonatal stool samples results in higher levels of tumour necrosis factor alpha (TNF-α) in the case of CSD extracts over time, compared to extracts from VD infants for which no such changes were observed during the first year of life. Functional analyses of the VD metagenomes at 1 year of age demonstrate a significant increase in the biosynthesis of the natural antibiotics, carbapenem and phenazine. Concurrently, we find antimicrobial resistance (AMR) genes against several classes of antibiotics in both VD and CSD. The abundance of AMR genes against synthetic (including semi-synthetic) agents such as phenicol, pleuromutilin and diaminopyrimidine are increased in CSD children at day 5 after birth. In addition, we find that mobile genetic elements, including phages, encode AMR genes such as glycopeptide, diaminopyrimidine and multidrug resistance genes. Our results demonstrate persistent effects at 1 year of life resulting from birth mode-dependent differences in earliest gut microbiome colonisation.

RevDate: 2023-01-30
CmpDate: 2023-01-30

Chiu CY, Chang KC, Chang LC, et al (2023)

Phenotype-specific signatures of systems-level gut microbiome associated with childhood airway allergies.

Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology, 34(1):e13905.

BACKGROUND: Perturbation of gut symbiosis has been linked to childhood allergic diseases. However, the underlying host-microbe interaction connected with specific phenotypes is poorly understood.

METHODS: To address this, integrative analyses of stool metagenomic and metabolomic profiles associated with IgE reactions in 56 children with mite-sensitized airway allergies (25 with rhinitis and 31 with asthma) and 28 nonallergic healthy controls were conducted.

RESULTS: We noted a decrease in the number and abundance of gut microbiome-encoded carbohydrate-active enzyme (CAZyme) genes, accompanied with a reduction in species richness, in the asthmatic gut microflora but not in that from allergic rhinitis. Such loss of CAZymes was consistent with the observation that a CAZyme-linked decrease in fecal butyrate was found in asthmatics and negatively correlated with mite-specific IgE responses. Different from the CAZymes, we demonstrated an increase in α diversity at the virulome levels in asthmatic gut microbiota and identified phenotype-specific variations of gut virulome. Moreover, use of fecal metagenomic and metabolomic signatures resulted in distinct effects on differentiating rhinitis and asthma from nonallergic healthy controls.

CONCLUSION: Overall, our integrative analyses reveal several signatures of systems-level gut microbiome in robust associations with fecal metabolites and disease phenotypes, which may be of etiological and diagnostic implications in childhood airway allergies.

RevDate: 2023-01-30
CmpDate: 2023-01-30

Nagata N, Takeuchi T, Masuoka H, et al (2023)

Human Gut Microbiota and Its Metabolites Impact Immune Responses in COVID-19 and Its Complications.

Gastroenterology, 164(2):272-288.

BACKGROUND & AIMS: We investigate interrelationships between gut microbes, metabolites, and cytokines that characterize COVID-19 and its complications, and we validate the results with follow-up, the Japanese 4D (Disease, Drug, Diet, Daily Life) microbiome cohort, and non-Japanese data sets.

METHODS: We performed shotgun metagenomic sequencing and metabolomics on stools and cytokine measurements on plasma from 112 hospitalized patients with SARS-CoV-2 infection and 112 non-COVID-19 control individuals matched by important confounders.

RESULTS: Multiple correlations were found between COVID-19-related microbes (eg, oral microbes and short-chain fatty acid producers) and gut metabolites (eg, branched-chain and aromatic amino acids, short-chain fatty acids, carbohydrates, neurotransmitters, and vitamin B6). Both were also linked to inflammatory cytokine dynamics (eg, interferon γ, interferon λ3, interleukin 6, CXCL-9, and CXCL-10). Such interrelationships were detected highly in severe disease and pneumonia; moderately in the high D-dimer level, kidney dysfunction, and liver dysfunction groups; but rarely in the diarrhea group. We confirmed concordances of altered metabolites (eg, branched-chain amino acids, spermidine, putrescine, and vitamin B6) in COVID-19 with their corresponding microbial functional genes. Results in microbial and metabolomic alterations with severe disease from the cross-sectional data set were partly concordant with those from the follow-up data set. Microbial signatures for COVID-19 were distinct from diabetes, inflammatory bowel disease, and proton-pump inhibitors but overlapping for rheumatoid arthritis. Random forest classifier models using microbiomes can highly predict COVID-19 and severe disease. The microbial signatures for COVID-19 showed moderate concordance between Hong Kong and Japan.

CONCLUSIONS: Multiomics analysis revealed multiple gut microbe-metabolite-cytokine interrelationships in COVID-19 and COVID-19related complications but few in gastrointestinal complications, suggesting microbiota-mediated immune responses distinct between the organ sites. Our results underscore the existence of a gut-lung axis in COVID-19.

RevDate: 2023-01-30
CmpDate: 2023-01-30

Frankot MA, O'Hearn CM, Blancke AM, et al (2023)

Acute gut microbiome changes after traumatic brain injury are associated with chronic deficits in decision-making and impulsivity in male rats.

Behavioral neuroscience, 137(1):15-28.

The mechanisms underlying chronic psychiatric-like impairments after traumatic brain injury (TBI) are currently unknown. The goal of the present study was to assess the role of diet and the gut microbiome in psychiatric symptoms after TBI. Rats were randomly assigned to receive a high-fat diet (HFD) or calorie-matched low-fat diet (LFD). After 2 weeks of free access, rats began training on the rodent gambling task (RGT), a measure of risky decision-making and motor impulsivity. After training, rats received a bilateral frontal TBI or a sham procedure and continued postinjury testing for 10 weeks. Fecal samples were collected before injury and 3-, 30-, and 60 days postinjury to evaluate the gut microbiome. HFD altered the microbiome, but ultimately had low-magnitude effects on behavior and did not modify functional outcomes after TBI. Injury-induced functional deficits were far more robust; TBI substantially decreased optimal choice and increased suboptimal choice and motor impulsivity on the RGT. TBI also affected the microbiome, and a model comparison approach revealed that bacterial diversity measured 3 days postinjury was predictive of chronic psychiatric-like deficits on the RGT. A functional metagenomic analysis identified changes to dopamine and serotonin synthesis pathways as a potential candidate mechanism. Thus, the gut may be a potential acute treatment target for psychiatric symptoms after TBI, as well as a biomarker for injury and deficit severity. However, further research will be needed to confirm and extend these findings. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

RevDate: 2023-01-27
CmpDate: 2023-01-27

Wu Z, Han Y, Wan Y, et al (2023)

Oral microbiome and risk of incident head and neck cancer: A nested case-control study.

Oral oncology, 137:106305.

OBJECTIVES: This nested case-control study in the NIH-AARP Diet and Health Study was carried out to prospectively investigate the relationship of oral microbiome with head and neck cancer (HNC).

MATERIALS AND METHODS: 56 incident HNC cases were identified, and 112 controls were incidence-density matched to cases. DNA extracted from pre-diagnostic oral wash samples was whole-genome shotgun metagenomic sequenced to measure the overall oral microbiome. ITS2 gene qPCR was used to measure the presence of fungi. ITS2 gene sequencing was performed on ITS2 gene qPCR positive samples. We computed taxonomic and functional alpha-diversity and beta-diversity metrics. The presence and relative abundance of groups of red-complex (e.g., Porphyromonas gingivalis) and/or orange-complex (e.g., Fusobacterium nucleatum) periodontal pathogens were compared between cases and controls using conditional logistic regression models and MiRKAT.

RESULTS: Participants with higher taxonomic microbial alpha-diversity had a non-statistically significant decreased risk of HNC. No case-control differences were found for beta diversity by MiRKAT model (all p > 0.05). A greater relative abundance of red-complex periodontal pathogens (OR = 0.51, 95 % CI = 0.26-1.00), orange-complex (OR = 0.38, 95 % CI = 0.18-0.83), and both complexes' pathogens (OR = 0.32, 95 % CI = 0.14-0.75), were associated with reduced risk of HNC. The presence of oral fungi was also strongly associated with reduced risk of HNC compared with controls (OR = 0.39, 95 % CI = 0.17-0.92).

CONCLUSION: Greater taxonomic alpha-diversity, the presence of oral fungi, and the presence or relative abundance of multiple microbial species, including the red- and orange-complex periodontal pathogens, were associated with reduced risk of HNC. Future studies with larger sample sizes are needed to evaluate these associations.

RevDate: 2023-01-26
CmpDate: 2023-01-26

Panda A, T Tuller (2023)

Determinants of associations between codon and amino acid usage patterns of microbial communities and the environment inferred based on a cross-biome metagenomic analysis.

NPJ biofilms and microbiomes, 9(1):5.

Codon and amino acid usage were associated with almost every aspect of microbial life. However, how the environment may impact the codon and amino acid choice of microbial communities at the habitat level is not clearly understood. Therefore, in this study, we analyzed codon and amino acid usage patterns of a large number of environmental samples collected from diverse ecological niches. Our results suggested that samples derived from similar environmental niches, in general, show overall similar codon and amino acid distribution as compared to samples from other habitats. To substantiate the relative impact of the environment, we considered several factors, such as their similarity in GC content, or in functional or taxonomic abundance. Our analysis demonstrated that none of these factors can fully explain the trends that we observed at the codon or amino acid level implying a direct environmental influence on them. Further, our analysis demonstrated different levels of selection on codon bias in different microbial communities with the highest bias in host-associated environments such as the digestive system or oral samples and the lowest level of selection in soil and water samples. Considering a large number of metagenomic samples here we showed that microorganisms collected from similar environmental backgrounds exhibit similar patterns of codon and amino acid usage irrespective of the location or time from where the samples were collected. Thus our study suggested a direct impact of the environment on codon and amino usage of microorganisms that cannot be explained considering the influence of other factors.

RevDate: 2023-01-26
CmpDate: 2023-01-26

Zhu G, Chao H, Sun M, et al (2023)

Toxicity sharing model of earthworm intestinal microbiome reveals shared functional genes are more powerful than species in resisting pesticide stress.

Journal of hazardous materials, 446:130646.

Earthworm intestinal bacteria and indigenous soil bacteria work closely during various biochemical processes and play a crucial role in maintaining the internal stability of the soil environment. However, the response mechanism of these bacterial communities to external pesticide disturbance is unknown. In this study, soil and earthworm gut contents were metagenomically sequenced after exposure to various concentrations of nitrochlorobenzene (0-1026.7 mg kg[-1]). A high degree of similarity was found between the microbial community composition and abundance in the worm gut and soil, both of which decreased significantly (P < 0.05) under elevated pesticide stress. The toxicity sharing model (TSM) showed that the toxicity sharing capacity was 97.4-125.7 % and 100.4-130.2 % for Egenes (genes in the worm gut) and Emet(degradation genes in the worm gut) in the earthworm intestinal microbiome, respectively. This indicated that the earthworm intestinal microbiome assisted in relieving the pesticide toxicity of the indigenous soil microbiome. This study showed that the TSM could quantitatively describe the toxic effect of pesticides on the earthworm intestinal microbiome. It provides a new analytical model for investigating the ecological alliance between earthworm intestinal microbiome and indigenous soil microbiome under pesticide stress while contributing a more profound understanding of the potential to use earthworms to mitigate pesticide pollution in soils and develop earthworm-based soil remediation techniques.

RevDate: 2023-01-26
CmpDate: 2023-01-26

Fraser MW, Martin BC, Wong HL, et al (2023)

Sulfide intrusion in a habitat forming seagrass can be predicted from relative abundance of sulfur cycling genes in sediments.

The Science of the total environment, 864:161144.

Sulfide intrusion from sediments is an increasingly recognized contributor to seagrass declines globally, yet the relationship between sediment microorganisms and sulfide intrusion has received little attention. Here, we use metagenomic sequencing and stable isotope ([34]S) analysis to examine this relationship in Cockburn Sound, Australia, a seagrass-dominated embayment with a gradient of sulfide stress and seagrass declines. There was a significant positive relationship between sulfide intrusion into seagrasses and sulfate reduction genes in sediment microbial communities, which was greatest at sites with long term seagrass declines. This is the first demonstration of a significant link between sulfur cycling genes present in seagrass sediments and sulfide intrusion in a habitat-forming seagrass that is experiencing long-term shoot density decline. Given that microorganisms respond rapidly to environmental change, the quantitative links established in this study can be used as a potential management tool to enable the prediction of sulfide stress on large habitat forming seagrasses; a global issue expected to worsen with climate change.

RevDate: 2023-01-26
CmpDate: 2023-01-26

Tao Y, Shen L, Han S, et al (2023)

Metagenomic study of carbon metabolism in black soil microbial communities under lead-lanthanum stress.

Journal of hazardous materials, 446:130666.

Pollution of soil environments with heavy metals (HMs) and rare earth elements (REEs) cannot be ignored. We aimed to determine the effects of lead combined with lanthanum (Pb-La) on microbial community structure, carbon metabolism, and differences in carbon source utilization in black soils using EcoPlates™ and a macrogenomic approach. We found that Pb and La contents and the microbial community structure together influence and shape the response of soil carbon metabolism to Pb-La. Compared with controls, microorganisms under pollution stress preferentially use phenolic and carboxylic acids as growth carbon sources. Under Pb-La stress, the relative abundance of Proteobacteria significantly increased, thereby selectively displacing heavy metal-sensitive phyla, such as Chloroflexi, Acidobacteria, and Thaumarchaeota. Altered functional potential of the microbial carbon cycle manifested as differences in carbon metabolism, methane metabolism, and carbon fixation pathways. Furthermore, an appropriate concentration of La can reduce the environmental toxicity of Pb, whereas a high concentration of La has synergistic toxicity with Pb. These findings have important implications for understanding the impact of HM-REE contamination in microbial communities and the functions associated with carbon metabolism in black soils.

RevDate: 2023-01-26
CmpDate: 2023-01-26

Dreisbach C, Alhusen J, Prescott S, et al (2023)

Metagenomic characterization of the maternal prenatal gastrointestinal microbiome by pregravid BMI.

Obesity (Silver Spring, Md.), 31(2):412-422.

OBJECTIVE: The incidence of women entering into pregnancy with BMI indicating overweight or obesity is rising with concurrent increases in adverse complications such as gestational diabetes. Although several studies have examined the compositional changes to the microbiome across BMI classifications, there has been no investigation regarding changes in microbial function during pregnancy.

METHODS: A total of 105 gastrointestinal microbiome biospecimens were used in this analysis. Biospecimens were sequenced by using the Illumina NovaSeq 6000 shotgun metagenomics platform.

RESULTS: Findings indicate an enrichment in microbiota from the phylum Firmicutes across all pregravid BMI groups with a decrease in α diversity in groups with BMI indicating obesity or overweight compared with a group with BMI indicating normal weight (p = 0.02). More specifically, women with BMI indicating obesity or overweight had enrichment in Bifidobacterium bifidum and B. adolescentis. Women with BMI > 25 kg/m[2] had a higher abundance of microbiota that support biotin synthesis and regulate epithelial cells in the lower gastrointestinal tract. These epithelial cells are responsible for host adaptability to dietary lipid variation and caloric absorption.

CONCLUSIONS: Our analysis suggests that there are differences in microbial composition and function between BMI groups. Future research should consider how these changes contribute to specific clinical outcomes during pregnancy.

RevDate: 2023-01-25

Naumova NB, MR Kabilov (2022)

About the Biodiversity of the Air Microbiome.

Acta naturae, 14(4):50-56.

This brief review focuses on the properties of bioaerosols, presenting some recent results of metagenomic studies of the air microbiome performed using next-generation sequencing. The taxonomic composition and structure of the bioaerosol microbiome may display diurnal and seasonal dynamics and be dependent on meteorological events such as dust storms, showers, fogs, etc., as well as air pollution. The Proteobacteria and Ascomycota members are common dominants in bioaerosols in different troposphere layers. The microbiological composition of the lower troposphere air affects the composition and diversity of the indoor bioaerosol microbiome, and information about the latter is very important, especially during exacerbated epidemiological situations. Few studies focusing on the bioaerosol microbiome of the air above Russia urge intensification of such research.

RevDate: 2023-01-25
CmpDate: 2023-01-25

Blohs M, Mahnert A, Brunnader K, et al (2023)

Acute appendicitis manifests as two microbiome state types with oral pathogens influencing severity.

Gut microbes, 15(1):2145845.

Mounting evidence suggests that acute appendicitis (AA) is not one but two diseases: complicated appendicitis, which is associated with necrosis leading to perforation or periappendicular abscess, and uncomplicated appendicitis, which does not necessarily result in perforation. Even though AA is the most frequent cause of surgery from abdominal pain, little is known about the origins and etiopathogenesis of this disease, much less regarding the different disease types. In this study, we investigated the microbiome (inter-domain amplicon and metagenome sequencing) of samples from the appendix, rectum and peritoneum of 60 children and adolescents with AA to assess the composition and potential function of bacteria, archaea and fungi. The analysis of the appendix microbial community revealed a shift depending on the severity of the AA. This shift was reflected by two major community state types that represented the complicated and uncomplicated cases. We could demonstrate that complicated, but not uncomplicated, appendicitis is associated with a significant local expansion of oral, bacterial pathogens in the appendix, most strongly influenced by necrotizing Fusobacterium spp., Porphyromonas and Parvimonas. Uncomplicated appendicitis, however, was characterized by gut-associated microbiomes. Our findings support the hypothesis that two disease types exist in AA, which cannot be distinguished beyond doubt using standard clinical characterization methods or by analysis of the patient's rectal microbiome. An advanced microbiome diagnosis, however, could improve non-surgical treatment of uncomplicated AA.

RevDate: 2023-01-24

Li Y, Xiong L, Yu H, et al (2023)

Biogeochemical sulfur cycling of virus auxiliary metabolic genes involved in Napahai plateau wetland.

Environmental science and pollution research international [Epub ahead of print].

Virus plays important roles in regulating microbial community structure, horizontal gene transfer, and promoting biological evolution, also augmenting host metabolism during infection via the expression of auxiliary metabolic genes (AMGs), and thus affect biogeochemical cycling in the oceans. As the "kidney of the earth," wetlands have rich biodiversity and abundant resources. Based on metagenomic data, 10 AMGs associated with sulfur cycling, i.e., tusA, moaD, dsrE, soxA, soxB, soxC, soxD, soxX, soxY, and soxZ, were analyzed in Napahai plateau wetland. The phylogenetic trees of AMGs involved in sulfur metabolism from different habitats and host origins were constructed. Combined with principal coordinate analysis, it revealed that most AMGs associated with sulfur metabolism clustered separately, indicating the abundance and uniqueness in this region. The sulfur metabolism pathways involved by AMGs were mainly SOX systems, among which sulfur oxidation was associated with moaD and dsrE genes, while sulfur transport was related to tusA genes. It provides an insight into the biogeochemical sulfur cycling in plateau wetlands and lays the foundation for further study on the co-evolution of virus and host.

RevDate: 2023-01-23

King WL, Richards SC, Kaminsky LM, et al (2023)

Leveraging microbiome rediversification for the ecological rescue of soil function.

Environmental microbiome, 18(1):7.

BACKGROUND: Global biodiversity losses threaten ecosystem services and can impact important functional insurance in a changing world. Microbial diversity and function can become depleted in agricultural systems and attempts to rediversify agricultural soils rely on either targeted microbial introductions or retaining natural lands as biodiversity reservoirs. As many soil functions are provided by a combination of microbial taxa, rather than outsized impacts by single taxa, such functions may benefit more from diverse microbiome additions than additions of individual commercial strains. In this study, we measured the impact of soil microbial diversity loss and rediversification (i.e. rescue) on nitrification by quantifying ammonium and nitrate pools. We manipulated microbial assemblages in two distinct soil types, an agricultural and a forest soil, with a dilution-to-extinction approach and performed a microbiome rediversification experiment by re-introducing microorganisms lost from the dilution. A microbiome water control was included to act as a reference point. We assessed disruption and potential restoration of (1) nitrification, (2) bacterial and fungal composition through 16S rRNA gene and fungal ITS amplicon sequencing and (3) functional genes through shotgun metagenomic sequencing on a subset of samples.

RESULTS: Disruption of nitrification corresponded with diversity loss, but nitrification was successfully rescued in the rediversification experiment when high diversity inocula were introduced. Bacterial composition clustered into groups based on high and low diversity inocula. Metagenomic data showed that genes responsible for the conversion of nitrite to nitrate and taxa associated with nitrogen metabolism were absent in the low diversity inocula microcosms but were rescued with high diversity introductions.

CONCLUSIONS: In contrast to some previous work, our data suggest that soil functions can be rescued by diverse microbiome additions, but that the concentration of the microbial inoculum is important. By understanding how microbial rediversification impacts soil microbiome performance, we can further our toolkit for microbial management in human-controlled systems in order to restore depleted microbial functions.

RevDate: 2023-01-23

Busi SB, de Nies L, Pramateftaki P, et al (2023)

Glacier-Fed Stream Biofilms Harbor Diverse Resistomes and Biosynthetic Gene Clusters.

Microbiology spectrum [Epub ahead of print].

Antimicrobial resistance (AMR) is a universal phenomenon the origins of which lay in natural ecological interactions such as competition within niches, within and between micro- to higher-order organisms. To study these phenomena, it is crucial to examine the origins of AMR in pristine environments, i.e., limited anthropogenic influences. In this context, epilithic biofilms residing in glacier-fed streams (GFSs) are an excellent model system to study diverse, intra- and inter-domain, ecological crosstalk. We assessed the resistomes of epilithic biofilms from GFSs across the Southern Alps (New Zealand) and the Caucasus (Russia) and observed that both bacteria and eukaryotes encoded twenty-nine distinct AMR categories. Of these, beta-lactam, aminoglycoside, and multidrug resistance were both abundant and taxonomically distributed in most of the bacterial and eukaryotic phyla. AMR-encoding phyla included Bacteroidota and Proteobacteria among the bacteria, alongside Ochrophyta (algae) among the eukaryotes. Additionally, biosynthetic gene clusters (BGCs) involved in the production of antibacterial compounds were identified across all phyla in the epilithic biofilms. Furthermore, we found that several bacterial genera (Flavobacterium, Polaromonas, Superphylum Patescibacteria) encode both atimicrobial resistance genes (ARGs) and BGCs within close proximity of each other, demonstrating their capacity to simultaneously influence and compete within the microbial community. Our findings help unravel how naturally occurring BGCs and AMR contribute to the epilithic biofilms mode of life in GFSs. Additionally, we report that eukaryotes may serve as AMR reservoirs owing to their potential for encoding ARGs. Importantly, these observations may be generalizable and potentially extended to other environments that may be more or less impacted by human activity. IMPORTANCE Antimicrobial resistance is an omnipresent phenomenon in the anthropogenically influenced ecosystems. However, its role in shaping microbial community dynamics in pristine environments is relatively unknown. Using metagenomics, we report the presence of antimicrobial resistance genes and their associated pathways in epilithic biofilms within glacier-fed streams. Importantly, we observe biosynthetic gene clusters associated with antimicrobial resistance in both pro- and eukaryotes in these biofilms. Understanding the role of resistance in the context of this pristine environment and complex biodiversity may shed light on previously uncharacterized mechanisms of cross-domain interactions.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Liu X, He G, Lan Y, et al (2022)

Virome and metagenomic analysis reveal the distinct distribution of microbiota in human fetal gut during gestation.

Frontiers in immunology, 13:1079294.

Studies have shown that fetal immune cell activation may result from potential exposure to microbes, although the presence of microbes in fetus has been a controversial topic. Here, we combined metagenomic and virome techniques to investigate the presence of bacteria and viruses in fetal tissues (small intestine, cecum, and rectum). We found that the fetal gut is not a sterile environment and has a low abundance but metabolically rich microbiome. Specifically, Proteobacteria and Actinobacteria were the dominant bacteria phyla of fetal gut. In total, 700 species viruses were detected, and Human betaherpesvirus 5 was the most abundant eukaryotic viruses. Especially, we first identified Methanobrevibacter smithii in fetal gut. Through the comparison with adults' gut microbiota we found that Firmicutes and Bacteroidetes gradually became the main force of gut microbiota during the process of growth and development. Interestingly, 6 antibiotic resistance genes were shared by the fetus and adults. Our results indicate the presence of microbes in the fetal gut and demonstrate the diversity of bacteria, archaea and viruses, which provide support for the studies related to early fetal immunity. This study further explores the specific composition of viruses in the fetal gut and the similarities between fetal and adults' gut microbiota, which is valuable for understanding human fetal immunity development during gestation.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Ezzamouri B, Rosario D, Bidkhori G, et al (2023)

Metabolic modelling of the human gut microbiome in type 2 diabetes patients in response to metformin treatment.

NPJ systems biology and applications, 9(1):2.

The human gut microbiome has been associated with several metabolic disorders including type 2 diabetes mellitus. Understanding metabolic changes in the gut microbiome is important to elucidate the role of gut bacteria in regulating host metabolism. Here, we used available metagenomics data from a metformin study, together with genome-scale metabolic modelling of the key bacteria in individual and community-level to investigate the mechanistic role of the gut microbiome in response to metformin. Individual modelling predicted that species that are increased after metformin treatment have higher growth rates in comparison to species that are decreased after metformin treatment. Gut microbial enrichment analysis showed prior to metformin treatment pathways related to the hypoglycemic effect were enriched. Our observations highlight how the key bacterial species after metformin treatment have commensal and competing behavior, and how their cellular metabolism changes due to different nutritional environment. Integrating different diets showed there were specific microbial alterations between different diets. These results show the importance of the nutritional environment and how dietary guidelines may improve drug efficiency through the gut microbiota.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Jansen D, J Matthijnssens (2023)

The Emerging Role of the Gut Virome in Health and Inflammatory Bowel Disease: Challenges, Covariates and a Viral Imbalance.

Viruses, 15(1):.

Virome research is a rapidly growing area in the microbiome field that is increasingly associated with human diseases, such as inflammatory bowel disease (IBD). Although substantial progress has been made, major methodological challenges limit our understanding of the virota. In this review, we describe challenges that must be considered to accurately report the virome composition and the current knowledge on the virome in health and IBD. First, the description of the virome shows strong methodological biases related to wetlab (e.g., VLP enrichment) and bioinformatics approaches (viral identification and classification). Second, IBD patients show consistent viral imbalances characterized by a high relative abundance of phages belonging to the Caudovirales and a low relative abundance of phages belonging to the Microviridae. Simultaneously, a sporadic contraction of CrAss-like phages and a potential expansion of the lysogenic potential of the intestinal virome are observed. Finally, despite numerous studies that have conducted diversity analysis, it is difficult to draw firm conclusions due to methodological biases. Overall, we present the many methodological and environmental factors that influence the virome, its current consensus in health and IBD, and a contributing hypothesis called the "positive inflammatory feedback loop" that may play a role in the pathophysiology of IBD.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Zhang F, Gia A, Chen G, et al (2022)

Critical Assessment of Whole Genome and Viral Enrichment Shotgun Metagenome on the Characterization of Stool Total Virome in Hepatocellular Carcinoma Patients.

Viruses, 15(1):.

Viruses are the most abundant form of life on earth and play important roles in a broad range of ecosystems. Currently, two methods, whole genome shotgun metagenome (WGSM) and viral-like particle enriched metagenome (VLPM) sequencing, are widely applied to compare viruses in various environments. However, there is no critical assessment of their performance in recovering viruses and biological interpretation in comparative viral metagenomic studies. To fill this gap, we applied the two methods to investigate the stool virome in hepatocellular carcinoma (HCC) patients and healthy controls. Both WGSM and VLPM methods can capture the major diversity patterns of alpha and beta diversities and identify the altered viral profiles in the HCC stool samples compared with healthy controls. Viral signatures identified by both methods showed reductions of Faecalibacterium virus Taranis in HCC patients' stool. Ultra-deep sequencing recovered more viruses in both methods, however, generally, 3 or 5 Gb were sufficient to capture the non-fragmented long viral contigs. More lytic viruses were detected than lysogenetic viruses in both methods, and the VLPM can detect the RNA viruses. Using both methods would identify shared and specific viral signatures and would capture different parts of the total virome.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Karpe AV, Hutton ML, Mileto SJ, et al (2023)

Gut Microbial Perturbation and Host Response Induce Redox Pathway Upregulation along the Gut-Liver Axis during Giardiasis in C57BL/6J Mouse Model.

International journal of molecular sciences, 24(2):.

Apicomplexan infections, such as giardiasis and cryptosporidiosis, negatively impact a considerable proportion of human and commercial livestock populations. Despite this, the molecular mechanisms of disease, particularly the effect on the body beyond the gastrointestinal tract, are still poorly understood. To highlight host-parasite-microbiome biochemical interactions, we utilised integrated metabolomics-16S rRNA genomics and metabolomics-proteomics approaches in a C57BL/6J mouse model of giardiasis and compared these to Cryptosporidium and uropathogenic Escherichia coli (UPEC) infections. Comprehensive samples (faeces, blood, liver, and luminal contents from duodenum, jejunum, ileum, caecum and colon) were collected 10 days post infection and subjected to proteome and metabolome analysis by liquid and gas chromatography-mass spectrometry, respectively. Microbial populations in faeces and luminal washes were examined using 16S rRNA metagenomics. Proteome-metabolome analyses indicated that 12 and 16 key pathways were significantly altered in the gut and liver, respectively, during giardiasis with respect to other infections. Energy pathways including glycolysis and supporting pathways of glyoxylate and dicarboxylate metabolism, and the redox pathway of glutathione metabolism, were upregulated in small intestinal luminal contents and the liver during giardiasis. Metabolomics-16S rRNA genetics integration indicated that populations of three bacterial families-Autopobiaceae (Up), Desulfovibrionaceae (Up), and Akkermanasiaceae (Down)-were most significantly affected across the gut during giardiasis, causing upregulated glycolysis and short-chained fatty acid (SCFA) metabolism. In particular, the perturbed Akkermanasiaceae population seemed to cause oxidative stress responses along the gut-liver axis. Overall, the systems biology approach applied in this study highlighted that the effects of host-parasite-microbiome biochemical interactions extended beyond the gut ecosystem to the gut-liver axis. These findings form the first steps in a comprehensive comparison to ascertain the major molecular and biochemical contributors of host-parasite interactions and contribute towards the development of biomarker discovery and precision health solutions for apicomplexan infections.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Ong SS, Xu J, Sim CK, et al (2023)

Profiling Microbial Communities in Idiopathic Granulomatous Mastitis.

International journal of molecular sciences, 24(2):.

Idiopathic granulomatous mastitis (IGM) is a rare and benign inflammatory breast disease with ambiguous aetiology. Contrastingly, lactational mastitis (LM) is commonly diagnosed in breastfeeding women. To investigate IGM aetiology, we profiled the microbial flora of pus and skin in patients with IGM and LM. A total of 26 patients with IGM and 6 patients with LM were included in the study. The 16S rRNA sequencing libraries were constructed from 16S rRNA gene amplified from total DNA extracted from pus and skin swabs in patients with IGM and LM controls. Constructed libraries were multiplexed and paired-end sequenced on HiSeq4000. Metagenomic analysis was conducted using modified microbiome abundance analysis suite customised R-resource for paired pus and skin samples. Microbiome multivariable association analyses were performed using linear models. A total of 21 IGM and 3 LM paired pus and skin samples underwent metagenomic analysis. Bray-Curtis ecological dissimilarity distance showed dissimilarity across four sample types (IGM pus, IGM skin, LM pus, and LM skin; PERMANOVA, p < 0.001). No characteristic dominant genus was observed across the IGM samples. The IGM pus samples were more diverse than corresponding IGM skin samples (Shannon and Simpson index; Wilcoxon paired signed-rank tests, p = 0.022 and p = 0.07). Corynebacterium kroppenstedtii, reportedly associated with IGM in the literature, was higher in IGM pus samples than paired skin samples (Wilcoxon, p = 0.022). Three other species and nineteen genera were statistically significant in paired IGM pus-skin comparison after antibiotic treatment adjustment and multiple comparisons correction. Microbial profiles are unique between patients with IGM and LM. Inter-patient variability and polymicrobial IGM pus samples cannot implicate specific genus or species as an infectious cause for IGM.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Zhang M, Wang X, Wang Z, et al (2023)

Metatranscriptomic Analyses Reveal Important Roles of the Gut Microbiome in Primate Dietary Adaptation.

Genes, 14(1):.

The gut microbiome plays a vital role in host ecological adaptation, especially dietary adaptations. Primates have evolved a variety of dietary and gut physiological structures that are useful to explore the role of the gut microbiome in host dietary adaptations. Here, we characterize gut microbiome transcriptional activity in ten fecal samples from primates with three different diets and compare the results to their previously reported metagenomic profile. Bacteria related to cellulose degradation, like Bacteroidaceae and Alcaligenaceae, were enriched and actively expressed in the gut microbiome of folivorous primates, and functional analysis revealed that the glycan biosynthesis and metabolic pathways were significantly active. In omnivorous primates, Helicobacteraceae, which promote lipid metabolism, were significantly enriched in expression, and activity and xenobiotic biodegradation and metabolism as well as lipid metabolism pathways were significantly active. In frugivorous primates, the abundance and activity of Elusimicrobiaceae, Neisseriaceae, and Succinivibrionaceae, which are associated with digestion of pectin and fructose, were significantly elevated, and the functional pathways involved in the endocrine system were significantly enriched. In conclusion, the gut microbiome contributes to host dietary adaptation by helping hosts digest the inaccessible nutrients in their specific diets.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Lin L, Lai Z, Zhang J, et al (2023)

The gastrointestinal microbiome in dairy cattle is constrained by the deterministic driver of the region and the modified effect of diet.

Microbiome, 11(1):10.

BACKGROUND: Dairy cattle (Bos taurus), especially Holstein cows, which are the highest-producing dairy animals and are widely bred to provide milk products to humans, rely critically on their associated gastrointestinal tract (GIT) microbiota to digest plant feed. However, the region-specific taxonomic composition and function of the GIT microbiome in dairy cattle and the mechanistic basis for the diet-induced effects remain to be elucidated. RESULTS: We collected 120 digesta samples from 10 GIT regions of 12 Holstein cows fed forage- and grain-based diets and characterized their GIT microbiome via functional shotgun metagenomics and the resolution of metagenome-assembled genomes. Our results demonstrated that the GIT microbiome was mainly partitioned into three distinct clusters, four-chambered stomach, small intestine, and large intestine. Moreover, we found that the four-chambered stomach microbiome with the highest diversity had a strong ability to degrade recalcitrant polysaccharide substrates, underpinned by the prevalence of potential cellulosome--producing and plant-derived polysaccharide utilization loci-encoding consortia. In contrast, the post-gastric intestinal microbiome orchestrated alternative fermentation pathways to adapt to nutrient availability and energy acquisition. Diet shifts selectively modified the metabolic cascades of the microbiome in specific GIT regions, evidenced by the loss of fiber-degrading taxa and increased hydrogen sinks in propionate after grain introduction.

CONCLUSIONS: Our findings provide new insights into GIT microbial organization and function in dairy cattle by GIT regions and diet regimes, which offers clues for improving animal production and health in the future. Video Abstract.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Zhao P, Liu B, Zhao H, et al (2023)

Significant changes in soil microbial community structure and metabolic function after Mikania micrantha invasion.

Scientific reports, 13(1):1141.

Currently, Mikania micrantha (M. micrantha) has invaded Guangdong, Guangxi and other provinces in China, causing serious harm to the forests of southeastern China. Soil microorganisms play an important role in the establishment of M. micrantha invasion, affecting plant productivity, community dynamics, and ecosystem function. However, at present, how M. micrantha invasion affects soil carbon, nitrogen, and phosphorus phase functional genes and the environmental factors that cause gene expression changes remain unclear, especially in subtropical forest ecosystems. This study was conducted in Xiangtoushan National Forest Park in Guangdong Province to compare the changes in soil nutrients and microorganisms after M. micrantha invasion of a forest. The microbial community composition and metabolic function were explored by metagenome sequencing. Our results showed that after M. micrantha invasion, the soil was more suitable for the growth of gram-positive bacteria (Gemmatimonadetes). In addition, the soil microbial community structure and enzyme activity increased significantly after M. micrantha invasion. Correlation analysis and Mantel test results suggested that total phosphorus (TP), nitrate nitrogen (NO3[-]-N), and soil dissolved organic matter (DOM; DOC and DON), were the strong correlates of soil microbial nitrogen functional genes, while soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (Soil-AP) were strongly correlated with the expression of soil microbial phosphorus functional gene. Mikania micrantha invasion alters soil nutrients, microbial community composition and metabolic function in subtropical forests, creates a more favorable growth environment, and may form a positive feedback process conducive to M. micrantha invasion.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Candel S, Tyrkalska SD, Álvarez-Santacruz C, et al (2023)

The nasopharyngeal microbiome in COVID-19.

Emerging microbes & infections, 12(1):e2165970.

The development of novel culture-independent techniques of microbial identification has allowed a rapid progress in the knowledge of the nasopharyngeal microbiota and its role in health and disease. Thus, it has been demonstrated that the nasopharyngeal microbiota defends the host from invading pathogens that enter the body through the upper airways by participating in the modulation of innate and adaptive immune responses. The current COVID-19 pandemic has created an urgent need for fast-track research, especially to identify and characterize biomarkers to predict the disease severity and outcome. Since the nasopharyngeal microbiota diversity and composition could potentially be used as a prognosis biomarker for COVID-19 patients, which would pave the way for strategies aiming to reduce the disease severity by modifying such microbiota, dozens of research articles have already explored the possible associations between changes in the nasopharyngeal microbiota and the severity or outcome of COVID-19 patients. Unfortunately, results are controversial, as many studies with apparently similar experimental designs have reported contradictory data. Herein we put together, compare, and discuss all the relevant results on this issue reported to date. Even more interesting, we discuss in detail which are the limitations of these studies, that probably are the main sources of the high variability observed. Therefore, this work is useful not only for people interested in current knowledge about the relationship between the nasopharyngeal microbiota and COVID-19, but also for researchers who want to go further in this field while avoiding the limitations and variability of previous works.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Tang F, Li Q, Yue J, et al (2023)

Penicillium oxalicum augments soil lead immobilization by affecting indigenous microbial community structure and inorganic phosphate solubilization potential during microbial-induced phosphate precipitation.

Environmental pollution (Barking, Essex : 1987), 319:120953.

Phosphate-solubilizing microorganisms (PSMs) are critically important for increasing soil phosphate (P) and decreasing lead (Pb) bioavailability during microbial-induced phosphate precipitation (MIPP). However, their relative contributions to the indigenous soil microbial communities and P-cycling genes during the MIPP process remain unclear. In this study, inoculation of the PSM P. oxalicum in hydroxyapatite-cultured and Pb-contaminated soil increased soil phosphatase activities, available P (AP) concentrations and reduced available Pb levels. Metagenomics revealed a 3.9-44.0% increase in the abundance of P-cycling genes by P. oxalicum inoculation. No P-cycling genes were assigned to Penicillium. While P. oxalicum increased the complexity of microbial community co-occurrence networks, and improved the directly interrelationships between Penicillium and genera containing P-cycling gene. These results suggesting that P. oxalicum obviously positively affected the regulation of indigenous P-cycling functional communities during the MIPP process. Inorganic P solubilization genes (gcd, ppa, and ppx) have been shown to affect soil AP, suggesting that inorganic P solubilization is the major driver of Pb immobilization improvement following P. oxalicum inoculation. These results enhance our understanding of the significant ecological role of PSMs in governing soil P-cycling and alleviating Pb[2+] biotoxicity during the MIPP process.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Krukowski H, Valkenburg S, Madella AM, et al (2023)

Gut microbiome studies in CKD: opportunities, pitfalls and therapeutic potential.

Nature reviews. Nephrology, 19(2):87-101.

Interest in gut microbiome dysbiosis and its potential association with the development and progression of chronic kidney disease (CKD) has increased substantially in the past 6 years. In parallel, the microbiome field has matured considerably as the importance of host-related and environmental factors is increasingly recognized. Past research output in the context of CKD insufficiently considered the myriad confounding factors that are characteristic of the disease. Gut microbiota-derived metabolites remain an interesting therapeutic target to decrease uraemic (cardio)toxicity. However, future studies on the effect of dietary and biotic interventions will require harmonization of relevant readouts to enable an in-depth understanding of the underlying beneficial mechanisms. High-quality standards throughout the entire microbiome analysis workflow are also of utmost importance to obtain reliable and reproducible results. Importantly, investigating the relative composition and abundance of gut bacteria, and their potential association with plasma uraemic toxins levels is not sufficient. As in other fields, the time has come to move towards in-depth quantitative and functional exploration of the patient's gut microbiome by relying on confounder-controlled quantitative microbial profiling, shotgun metagenomics and in vitro simulations of microorganism-microorganism and host-microorganism interactions. This step is crucial to enable the rational selection and monitoring of dietary and biotic intervention strategies that can be deployed as a personalized intervention in CKD.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Hammer TJ, Easton-Calabria A, NA Moran (2023)

Microbiome assembly and maintenance across the lifespan of bumble bee workers.

Molecular ecology, 32(3):724-740.

How a host's microbiome changes over its lifespan can influence development and ageing. As these temporal patterns have only been described in detail for a handful of hosts, an important next step is to compare microbiome succession more broadly and investigate why it varies. Here we characterize the temporal dynamics and stability of the bumble bee worker gut microbiome. Bumble bees have simple and host-specific gut microbiomes, and their microbial dynamics may influence health and pollination services. We used 16S rRNA gene sequencing, quantitative PCR and metagenomics to characterize gut microbiomes over the lifespan of Bombus impatiens workers. We also sequenced gut transcriptomes to examine host factors that may control the microbiome. At the community level, microbiome assembly is highly predictable and similar to patterns of primary succession observed in the human gut. However, at the strain level, partitioning of bacterial variants among colonies suggests stochastic colonization events similar to those observed in flies and nematodes. We also find strong differences in temporal dynamics among symbiont species, suggesting ecological differences among microbiome members in colonization and persistence. Finally, we show that both the gut microbiome and host transcriptome-including expression of key immunity genes-stabilize, as opposed to senesce, with age. We suggest that in highly social groups such as bumble bees, maintenance of both microbiomes and immunity contribute to inclusive fitness, and thus remain under selection even in old age. Our findings provide a foundation for exploring the mechanisms and functional outcomes of bee microbiome succession.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Larkin AA, Hagstrom GI, Brock ML, et al (2023)

Basin-scale biogeography of Prochlorococcus and SAR11 ecotype replication.

The ISME journal, 17(2):185-194.

Establishing links between microbial diversity and environmental processes requires resolving the high degree of functional variation among closely related lineages or ecotypes. Here, we implement and validate an improved metagenomic approach that estimates the spatial biogeography and environmental regulation of ecotype-specific replication patterns (RObs) across ocean regions. A total of 719 metagenomes were analyzed from meridional Bio-GO-SHIP sections in the Atlantic and Indian Ocean. Accounting for sequencing bias and anchoring replication estimates in genome structure were critical for identifying physiologically relevant biological signals. For example, ecotypes within the dominant marine cyanobacteria Prochlorococcus exhibited distinct diel cycles in RObs that peaked between 19:00-22:00. Additionally, both Prochlorococcus ecotypes and ecotypes within the highly abundant heterotroph Pelagibacter (SAR11) demonstrated systematic biogeographies in RObs that differed from spatial patterns in relative abundance. Finally, RObs was significantly regulated by nutrient stress and temperature, and explained by differences in the genomic potential for nutrient transport, energy production, cell wall structure, and replication. Our results suggest that our new approach to estimating replication is reflective of gross population growth. Moreover, this work reveals that the interaction between adaptation and environmental change drives systematic variability in replication patterns across ocean basins that is ecotype-specific, adding an activity-based dimension to our understanding of microbial niche space.

RevDate: 2023-01-24
CmpDate: 2023-01-24

Wanapaisan P, Chuansangeam M, Nopnipa S, et al (2022)

Association between Gut Microbiota with Mild Cognitive Impairment and Alzheimer's Disease in a Thai Population.

Neuro-degenerative diseases, 22(2):43-54.

BACKGROUND: Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are common in older adults. Much recent work has implicated the connection between the gut and the brain via bidirectional communication of the gastrointestinal tract and the central nervous system through biochemical signaling. Altered gut microbiota composition has shown controversial results based on geographic location, age, diet, physical activity, psychological status, underlying diseases, medication, and drug use.

OBJECTIVES: This study aimed to investigate the relationships of gut microbiota with MCI and AD.

METHODS: 16S metagenome profiles from stool collection of participant groups (normal; n = 20, MCI; n = 12, AD; n = 20) were analyzed. The diagnosis of cognitive conditions was made by standard criteria consisting of clinical interviews, physical examinations, cognitive assessments, laboratory examinations, and neuroimaging by both structural neuroimaging and amyloid positron emission tomography scans. Correlations between medical factors with food frequency and the fecal microbiome were elucidated.

RESULTS: A significant difference at the operational taxonomic unit level was observed. The significantly higher abundance of bacteria in nondementia patients belonged to the Clostridiales order, including Clostridium sensu stricto 1 (p < 0.0001), Fusicatenibacter (p = 0.0007), Lachnospiraceae (p = 0.001), Agathobacter (p = 0.021), and Fecalibacterium (p < 0.0001). In contrast, Escherichia-Shigella (p = 0.0002), Bacteroides (p = 0.0014), Holdemanella (p < 0.0001), Romboutsia (p = 0.001), and Megamonas (p = 0.047) were the dominant genera in the AD group. Left and right hippocampus and right amygdala volumes were significantly decreased in the AD group (p < 0.001) and significantly correlated with the groups of bacteria that were significantly different between groups.

CONCLUSION: There was a relationship between the composition of the gut microbiome and neurodegenerative disorders, including MCI and AD. Reduction of Clostridiaceae and increases in Enterobacteriaceae and Bacteroides were associated with persons with MCI and AD, consistent with previous studies. The altered gut microbiome could be potentially targeted for the early diagnosis of dementia and the reduction of AD risk.

RevDate: 2023-01-22

Turner D, Shkoporov AN, Lood C, et al (2023)

Abolishment of morphology-based taxa and change to binomial species names: 2022 taxonomy update of the ICTV bacterial viruses subcommittee.

Archives of virology, 168(2):74.

This article summarises the activities of the Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses for the period of March 2021-March 2022. We provide an overview of the new taxa proposed in 2021, approved by the Executive Committee, and ratified by vote in 2022. Significant changes to the taxonomy of bacterial viruses were introduced: the paraphyletic morphological families Podoviridae, Siphoviridae, and Myoviridae as well as the order Caudovirales were abolished, and a binomial system of nomenclature for species was established. In addition, one order, 22 families, 30 subfamilies, 321 genera, and 862 species were newly created, promoted, or moved.

RevDate: 2023-01-23

Andrianjakarivony HF, Bettarel Y, Armougom F, et al (2022)

Phage-Host Prediction Using a Computational Tool Coupled with 16S rRNA Gene Amplicon Sequencing.

Viruses, 15(1):.

Metagenomics studies have revealed tremendous viral diversity in aquatic environments. Yet, while the genomic data they have provided is extensive, it is unannotated. For example, most phage sequences lack accurate information about their bacterial host, which prevents reliable phage identification and the investigation of phage-host interactions. This study aimed to take this knowledge further, using a viral metagenomic framework to decipher the composition and diversity of phage communities and to predict their bacterial hosts. To this end, we used water and sediment samples collected from seven sites with varying contamination levels in the Ebrié Lagoon in Abidjan, Ivory Coast. The bacterial communities were characterized using the 16S rRNA metabarcoding approach, and a framework was developed to investigate the virome datasets that: (1) identified phage contigs with VirSorter and VIBRANT; (2) classified these contigs with MetaPhinder using the phage database (taxonomic annotation); and (3) predicted the phages' bacterial hosts with a machine learning-based tool: the Prokaryotic Virus-Host Predictor. The findings showed that the taxonomic profiles of phages and bacteria were specific to sediment or water samples. Phage sequences assigned to the Microviridae family were widespread in sediment samples, whereas phage sequences assigned to the Siphoviridae, Myoviridae and Podoviridae families were predominant in water samples. In terms of bacterial communities, the phyla Latescibacteria, Zixibacteria, Bacteroidetes, Acidobacteria, Calditrichaeota, Gemmatimonadetes, Cyanobacteria and Patescibacteria were most widespread in sediment samples, while the phyla Epsilonbacteraeota, Tenericutes, Margulisbacteria, Proteobacteria, Actinobacteria, Planctomycetes and Marinimicrobia were most prevalent in water samples. Significantly, the relative abundance of bacterial communities (at major phylum level) estimated by 16S rRNA metabarcoding and phage-host prediction were significantly similar. These results demonstrate the reliability of this novel approach for predicting the bacterial hosts of phages from shotgun metagenomic sequencing data.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Shang J, Tang X, Y Sun (2023)

PhaTYP: predicting the lifestyle for bacteriophages using BERT.

Briefings in bioinformatics, 24(1):.

Bacteriophages (or phages), which infect bacteria, have two distinct lifestyles: virulent and temperate. Predicting the lifestyle of phages helps decipher their interactions with their bacterial hosts, aiding phages' applications in fields such as phage therapy. Because experimental methods for annotating the lifestyle of phages cannot keep pace with the fast accumulation of sequenced phages, computational method for predicting phages' lifestyles has become an attractive alternative. Despite some promising results, computational lifestyle prediction remains difficult because of the limited known annotations and the sheer amount of sequenced phage contigs assembled from metagenomic data. In particular, most of the existing tools cannot precisely predict phages' lifestyles for short contigs. In this work, we develop PhaTYP (Phage TYPe prediction tool) to improve the accuracy of lifestyle prediction on short contigs. We design two different training tasks, self-supervised and fine-tuning tasks, to overcome lifestyle prediction difficulties. We rigorously tested and compared PhaTYP with four state-of-the-art methods: DeePhage, PHACTS, PhagePred and BACPHLIP. The experimental results show that PhaTYP outperforms all these methods and achieves more stable performance on short contigs. In addition, we demonstrated the utility of PhaTYP for analyzing the phage lifestyle on human neonates' gut data. This application shows that PhaTYP is a useful means for studying phages in metagenomic data and helps extend our understanding of microbial communities.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Wang Q, Chen J, Qi W, et al (2023)

Dam construction alters planktonic microbial predator‒prey communities in the urban reaches of the Yangtze River.

Water research, 230:119575.

While dam construction supports social and economic development, changes in hydraulic conditions can also affect natural aquatic ecosystems, especially microbial ecosystems. The compositional and functional traits of multi-trophic microbiota can be altered by dam construction, which may result in changes in aquatic predator-prey interactions. To understand this process, we performed a large-scale sampling campaign in the urban reaches of the dam-impacted Yangtze River (1 995 km) and obtained 211 metagenomic datasets and water quality data. We first compared the compositional traits of planktonic microbial communities upstream, downstream, and in a dam reservoir. Results showed that Bacteroidetes (R-strategy) bacteria were more likely to survive upstream, whilst the reservoir and downstream regions were more conducive to the survival of K-strategy bacteria such as Actinobacteria. Eukaryotic predators tended to be enriched upstream, whilst phototrophs tended to be enriched in the reservoir and downstream regions. Based on bipartite networks, we inferred that the potential microbial predator-prey interactions gradually and significantly decreased from upstream to the downstream and dam regions, affecting 56% of keystone microbial species. Remarkably, functional analysis showed that the abundance of the photosynthetic gene psbO was higher in the reservoir and downstream regions, whilst the abundance of the KEGG carbohydrate metabolic pathway was higher upstream. These results indicate that dam construction in the Yangtze River induced planktonic microbial ecosystem transformation from detritus-based food webs to autotroph-based food webs.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Yang L, J Chen (2023)

Benchmarking differential abundance analysis methods for correlated microbiome sequencing data.

Briefings in bioinformatics, 24(1):.

Differential abundance analysis (DAA) is one central statistical task in microbiome data analysis. A robust and powerful DAA tool can help identify highly confident microbial candidates for further biological validation. Current microbiome studies frequently generate correlated samples from different microbiome sampling schemes such as spatial and temporal sampling. In the past decade, a number of DAA tools for correlated microbiome data (DAA-c) have been proposed. Disturbingly, different DAA-c tools could sometimes produce quite discordant results. To recommend the best practice to the field, we performed the first comprehensive evaluation of existing DAA-c tools using real data-based simulations. Overall, the linear model-based methods LinDA, MaAsLin2 and LDM are more robust than methods based on generalized linear models. The LinDA method is the only method that maintains reasonable performance in the presence of strong compositional effects.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Baeza JA (2022)

Mitochondrial genomes assembled from non-invasive eDNA metagenomic scat samples in the endangered Amur tiger Panthera tigris altaica.

PeerJ, 10:e14428.

The Amur or Siberian tiger Panthera tigris altaica (Temminck, 1844) is currently restricted to a small region of its original geographical range in northwestern Asia and is considered 'endangered' by the IUCN Red List of Threatened Species. This solitary, territorial, and large top predator is in major need of genomic resources to inform conservation management strategies. This study formally tested if complete mitochondrial genomes of P. tigris altaica can be assembled from non-enriched metagenomic libraries generated from scat eDNA samples using the Illumina sequencing platform and open-access bioinformatics pipelines. The mitogenome of P. tigris altaica was assembled and circularized using the pipeline GetOrganelle with a coverage ranging from 322.7x to 17.6x in four different scat eDNA samples. A nearly complete mitochondrial genome (101x) was retrieved from a fifth scat eDNA sample. The complete or nearly complete mitochondrial genomes of P. tigris altaica were AT-rich and composed of 13 protein coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Synteny observed in all assembled mitogenomes was identical to that reported before for P. tigris altaica and other felids. A phylogenomic analysis based on all PCGs demonstrated that the mitochondrial genomes assembled from scat eDNA reliably identify the sequenced samples as belonging to P. tigris and distinguished the same samples from closely and distantly related congeneric species. This study demonstrates that it is viable to retrieve accurate whole and nearly complete mitochondrial genomes of P. tigris altaica (and probably other felids) from scat eDNA samples without library enrichment protocols and using open-access bioinformatics workflows. This new genomic resource represents a new tool to support conservation strategies (bio-prospecting and bio-monitoring) in this iconic cat.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Liu L, Wu P, Chen F, et al (2022)

Multi-omics analyses reveal that the gut microbiome and its metabolites promote milk fat synthesis in Zhongdian yak cows.

PeerJ, 10:e14444.

BACKGROUND: Yak cows produce higher quality milk with higher concentrations of milk fat than dairy cows. Recently, studies have found the yak milk yield and milk fat percentage have decreased significantly over the past decade, highlighting the urgency for yak milk improvement. Therefore, we aimed to analyze how the gut microbiome impacts milk fat synthesis in Zhongdian yak cows.

METHODS: We collected milk samples from Zhongdian yak cows and analyzed the milk fat percentage, selecting five Zhongdian yak cows with a very high milk fat percentage (>7%, 8.70 ± 1.89%, H group) and five Zhongdian yak cows with a very low milk fat percentage (<5%, 4.12 ± 0.43%, L group), and then obtained gut samples of these ten Zhongdian yak cows through rectal palpation. Gut metagenomics, metabolomics, and conjoint metagenomics and metabolomics analyses were performed on these samples, identifying taxonomic changes, functional changes, and changes in gut microbes-metabolite interactions within the milk fat synthesis-associated Zhongdian yak cows gut microbiome, to identify potential regulatory mechanisms of milk fat at the gut microbiome level in Zhongdian yak cows.

RESULTS: The metagenomics analysis revealed Firmicutes and Proteobacteria were significantly more abundant in the gut of the high-milk fat Zhongdian yak cows. These bacteria are involved in the biosynthesis of unsaturated fatty acids and amino acids, leading to greater efficiency in converting energy to milk fat. The metabolomics analysis showed that the elevated gut metabolites in high milk fat percentage Zhongdian yak cows were mainly enriched in lipid and amino acid metabolism. Using a combined metagenomic and metabolomics analysis, positive correlations between Firmicutes (Desulfocucumis, Anaerotignum, Dolosiccus) and myristic acid, and Proteobacteria (Catenovulum, Comamonas, Rubrivivax, Marivita, Succinimouas) and choline were found in the gut of Zhongdian yak cows. These interactions may be the main contributors to methanogen inhibition, producing less methane leading to higher-efficient milk fat production.

CONCLUSIONS: A study of the gut microbe, gut metabolites, and milk fat percentage of Zhongdian yak cows revealed that the variations in milk fat percentage between yak cows may be caused by the gut microbes and their metabolites, especially Firmicutes-myristic acid and Proteobacteria-choline interactions, which are important to milk fat synthesis. Our study provides new insights into the functional roles of the gut microbiome in producing small molecule metabolites and contributing to milk performance traits in yak cows.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Song A, Peng J, Si Z, et al (2023)

Metagenomics reveals the increased antibiotics resistome through prokaryote rather than virome after overuse of rare earth element compounds.

The Science of the total environment, 863:160704.

Rare earth elements (REE) are extensively exploited in the agricultural ecosystems due to their various beneficial roles on plant growth. However, the ecotoxicological effects and environmental risk of REE are poorly assessed. Here, we investigated the effects of lanthanum and cerium nitrate on soil prokaryote and viral metal resistance genes (MRGs) and antibiotics resistance genes (ARGs) using a metagenomic-based approach. We found that relative abundances of prokaryote phyla Bacteroidetes and Chloroflexi decreased with increasing of both REE compounds. In addition, low level REE nitrate (0.05 and 0.1 mmol kg[-1] soil) inhibited the viral family Phycodanaviridae, Rudiviridae, Schitoviridae, whereas high level (0.16 and 0.32 mmol kg[-1] soil) REE nitrate suppressed the viral family Herelleviridae, Iridoviridae, Podoviridae. ARGs were not significantly affected by low level of REE nitrate. However, high level of both REEs nitrate increased the abundances of dominant prokaryote genes resisting to most of the drug classes, such as aminoglycoside, elfamycin, fluoroquinolone, macrolide, rifamycin. Abundance of MRGs in prokaryote did not change consistently with REE nitrate compound type and input rate. MRGs were only partially detected in the virome in some of the treatments, while ARGs was not detected in virome. Together, we demonstrated that overuse of REE nitrate in agriculture would increase the risk of dissemination of ARGs through prokaryotes but not virus, although viral community was substantially shifted.

RevDate: 2023-01-23
CmpDate: 2023-01-23

Badran M, Khalyfa A, Ericsson AC, et al (2023)

Gut microbiota mediate vascular dysfunction in a murine model of sleep apnoea: effect of probiotics.

The European respiratory journal, 61(1): pii:13993003.00002-2022.

BACKGROUND: Obstructive sleep apnoea (OSA) is a chronic prevalent condition characterised by intermittent hypoxia (IH), and is associated with endothelial dysfunction and coronary artery disease (CAD). OSA can induce major changes in gut microbiome diversity and composition, which in turn may induce the emergence of OSA-associated morbidities. However, the causal effects of IH-induced gut microbiome changes on the vasculature remain unexplored. Our objective was to assess if vascular dysfunction induced by IH is mediated through gut microbiome changes.

METHODS: Faecal microbiota transplantation (FMT) was conducted on C57BL/6J naïve mice for 6 weeks to receive either IH or room air (RA) faecal slurry with or without probiotics (VSL#3). In addition to 16S rRNA amplicon sequencing of their gut microbiome, FMT recipients underwent arterial blood pressure and coronary artery and aorta function testing, and their trimethylamine N-oxide (TMAO) and plasma acetate levels were determined. Finally, C57BL/6J mice were exposed to IH, IH treated with VSL#3 or RA for 6 weeks, and arterial blood pressure and coronary artery function assessed.

RESULTS: Gut microbiome taxonomic profiles correctly segregated IH from RA in FMT mice and the normalising effect of probiotics emerged. Furthermore, IH-FMT mice exhibited increased arterial blood pressure and TMAO levels, and impairments in aortic and coronary artery function (p<0.05) that were abrogated by probiotic administration. Lastly, treatment with VSL#3 under IH conditions did not attenuate elevations in arterial blood pressure or CAD.

CONCLUSIONS: Gut microbiome alterations induced by chronic IH underlie, at least partially, the typical cardiovascular disturbances of sleep apnoea and can be mitigated by concurrent administration of probiotics.

RevDate: 2023-01-21

Cholleti H, de Jong J, Blomström AL, et al (2022)

Investigation of the Virome and Characterization of Issyk-Kul Virus from Swedish Myotis brandtii Bats.

Pathogens (Basel, Switzerland), 12(1): pii:pathogens12010012.

Bats are reservoirs for many different viruses, including some that can be transmitted to and cause disease in humans and/or animals. However, less is known about the bat-borne viruses circulating in Northern European countries such as in Sweden. In this study, saliva from Myotis brandtii bats, collected from south-central Sweden, was analyzed for viruses. The metagenomic analysis identified viral sequences belonging to different viral families, including, e.g., Nairoviridae, Retroviridae, Poxviridae, Herpesviridae and Siphoviridae. Interestingly, through the data analysis, the near-complete genome of Issyk-Kul virus (ISKV), a zoonotic virus within the Nairoviridae family, was obtained, showing 95-99% protein sequence identity to previously described ISKVs. This virus is believed to infect humans via an intermediate tick host or through contact with bat excrete. ISKV has previously been found in bats in Europe, but not previously in the Nordic region. In addition, near full-length genomes of two novel viruses belonging to Picornavirales order and Tymoviridae family were characterized. Taken together, our study has not only identified novel viruses, but also the presence of a zoonotic virus not previously known to circulate in this region. Thus, the results from these types of studies can help us to better understand the diversity of viruses circulating in bat populations, as well as identify viruses with zoonotic potential that could possibly be transmitted to humans.

RevDate: 2023-01-21

De Lise F, Iacono R, Moracci M, et al (2023)

Archaea as a Model System for Molecular Biology and Biotechnology.

Biomolecules, 13(1): pii:biom13010114.

Archaea represents the third domain of life, displaying a closer relationship with eukaryotes than bacteria. These microorganisms are valuable model systems for molecular biology and biotechnology. In fact, nowadays, methanogens, halophiles, thermophilic euryarchaeota, and crenarchaeota are the four groups of archaea for which genetic systems have been well established, making them suitable as model systems and allowing for the increasing study of archaeal genes' functions. Furthermore, thermophiles are used to explore several aspects of archaeal biology, such as stress responses, DNA replication and repair, transcription, translation and its regulation mechanisms, CRISPR systems, and carbon and energy metabolism. Extremophilic archaea also represent a valuable source of new biomolecules for biological and biotechnological applications, and there is growing interest in the development of engineered strains. In this review, we report on some of the most important aspects of the use of archaea as a model system for genetic evolution, the development of genetic tools, and their application for the elucidation of the basal molecular mechanisms in this domain of life. Furthermore, an overview on the discovery of new enzymes of biotechnological interest from archaea thriving in extreme environments is reported.

RevDate: 2023-01-20
CmpDate: 2023-01-20

Koonin EV, Krupovic M, VV Dolja (2023)

The global virome: How much diversity and how many independent origins?.

Environmental microbiology, 25(1):40-44.

Viruses are considered to be the most abundant biological entities on earth. They also display striking genetic diversity as emphatically demonstrated by the recent advances of metagenomics and metatranscriptomics. But what are the limits of this diversity, that is, how many virus species in the earth virome? By combining the available estimates of the number of prokaryote species with those of the virome size, we obtain back-of-the-envelope estimates of the total number of distinct virus species, which come out astronomically large, from about 10[7] to about 10[9] . The route of virus origins apparently involved non-viral replicators capturing and exapting various cellular proteins to become virus capsid subunits. How many times in the history of life has this happened? In other words, how many realms of viruses, the highest rank taxa that are supposed to be monophyletic, comprise the global virome? We argue that viruses emerged on a number (even if far from astronomical) independent occasions, so the number of realms will considerably increase from the current 6, by splitting some of the current realms, giving the realm status to some of the currently unclassified groups of viruses and discovery of new distinct groups.

RevDate: 2023-01-20
CmpDate: 2023-01-20

Tran HT, Nguyen HM, Nguyen TM, et al (2023)

Microbial Communities Along 2,3,7,8-tetrachlorodibenzodioxin Concentration Gradient in Soils Polluted with Agent Orange Based on Metagenomic Analyses.

Microbial ecology, 85(1):197-208.

The 2,3,7,8-tetrachlorodibenzodioxin (TCDD), a contaminant in Agent Orange released during the US-Vietnam War, led to a severe environmental crisis. Approximately, 50 years have passed since the end of this war, and vegetation has gradually recovered from the pollution. Soil bacterial communities were investigated by 16S metagenomics in habitats with different vegetation physiognomies in Central Vietnam, namely, forests (S0), barren land (S1), grassland (S2), and developing woods (S3). Vegetation complexity was negatively associated with TCDD concentrations, revealing the reasoning behind the utilization of vegetation physiognomy as an indicator for ecological succession along the gradient of pollutants. Stark changes in bacterial composition were detected between S0 and S1, with an increase in Firmicutes and a decrease in Acidobacteria and Bacteroidetes. Notably, dioxin digesters Arthrobacter, Rhodococcus, Comamonadaceae, and Bacialles were detected in highly contaminated soil (S1). Along the TCDD gradients, following the dioxin decay from S1 to S2, the abundance of Firmicutes and Actinobacteria decreased, while that of Acidobacteria increased; slight changes occurred at the phylum level from S2 to S3. Although metagenomics analyses disclosed a trend toward bacterial communities before contamination with vegetation recovery, non-metric multidimensional scaling analysis unveiled a new trajectory deviating from the native state. Recovery of the bacterial community may have been hindered, as indicated by lower bacterial diversity in S3 compared to S0 due to a significant loss of bacterial taxa and recruitment of fewer colonizers. The results indicate that dioxins significantly altered the soil microbiomes into a state of disorder with a deviating trajectory in restoration.

RevDate: 2023-01-20
CmpDate: 2023-01-20

Trzebny A, Slodkowicz-Kowalska A, Björkroth J, et al (2023)

Microsporidian Infection in Mosquitoes (Culicidae) Is Associated with Gut Microbiome Composition and Predicted Gut Microbiome Functional Content.

Microbial ecology, 85(1):247-263.

The animal gut microbiota consist of many different microorganisms, mainly bacteria, but archaea, fungi, protozoans, and viruses may also be present. This complex and dynamic community of microorganisms may change during parasitic infection. In the present study, we investigated the effect of the presence of microsporidians on the composition of the mosquito gut microbiota and linked some microbiome taxa and functionalities to infections caused by these parasites. We characterised bacterial communities of 188 mosquito females, of which 108 were positive for microsporidian DNA. To assess how bacterial communities change during microsporidian infection, microbiome structures were identified using 16S rRNA microbial profiling. In total, we identified 46 families and four higher taxa, of which Comamonadaceae, Enterobacteriaceae, Flavobacteriaceae and Pseudomonadaceae were the most abundant mosquito-associated bacterial families. Our data suggest that the mosquito gut microbial composition varies among host species. In addition, we found a correlation between the microbiome composition and the presence of microsporidians. The prediction of metagenome functional content from the 16S rRNA gene sequencing suggests that microsporidian infection is characterised by some bacterial species capable of specific metabolic functions, especially the biosynthesis of ansamycins and vancomycin antibiotics and the pentose phosphate pathway. Moreover, we detected a positive correlation between the presence of microsporidian DNA and bacteria belonging to Spiroplasmataceae and Leuconostocaceae, each represented by a single species, Spiroplasma sp. PL03 and Weissella cf. viridescens, respectively. Additionally, W. cf. viridescens was observed only in microsporidian-infected mosquitoes. More extensive research, including intensive and varied host sampling, as well as determination of metabolic activities based on quantitative methods, should be carried out to confirm our results.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Zhao N, Zhang Q, Guo Y, et al (2023)

Oral microbiome contributes to the failure of orthodontic temporary anchorage devices (TADs).

BMC oral health, 23(1):22.

BACKGROUND: The stability of temporary anchorage devices (TADs) is critical in orthodontic clinics. The failure of TADs is multifactorial, and the role of the oral microbiome has not been clearly defined. Herein, we attempted to analyze the contribution of the oral microbiome to the failure of TADs.

METHODS: Next-generation sequencing was adopted for analyzing the microbiome on the TADs from orthodontic patients. 29 TADs (15 failed TADs and 14 successful TADs) were used for 16S rRNA gene sequencing. A total of 135 TADs (62 failed TADs and 73 successful TADs) were collected to conduct metagenomic sequencing. Additionally, 34 verified samples (18 failed TADs and 16 successful TADs) were collected for quantitative real-time polymerase chain reaction analysis (qRT-PCR).

RESULTS: Successful and failed TADs demonstrated discrepancies in microbiome structure, composition, and function. Clear separations were found in β-diversity in 16S rRNA gene sequencing as well as metagenomic sequencing (p < 0.05). Metagenomic sequencing showed that Prevotella intermedia, Eikenella corrodens, Parvimonas spp., Neisseria elongata, and Catonella morbi were enriched in the failed groups. qRT-PCR also demonstrated that the absolute bacteria load of Prevotella intermedia was higher in failed TADs (p < 0.05). Considering functional aspects, the failed group showed enriched genes involved in flagellar assembly, bacterial chemotaxis, and oxidative phosphorylation.

CONCLUSIONS: This study illustrated the compositional and functional differences of microorganisms found on successful and failed TADs, indicating that controlling bacterial adhesion on the surface of TADs is essential for their success rate.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Rivera-Gutiérrez X, Morán P, Taboada B, et al (2023)

The fecal and oropharyngeal eukaryotic viromes of healthy infants during the first year of life are personal.

Scientific reports, 13(1):938.

Using a metagenomic sequencing approach, we described and compared the diversity and dynamics of the oropharyngeal and fecal eukaryotic virome of nine asymptomatic children in a semi-rural community setting located in the State of Morelos, Mexico. Ninety oropharyngeal swabs and 97 fecal samples were collected starting 2 weeks after birth and monthly thereafter until 12 months of age. In both niches, more than 95% of the total sequence reads were represented by viruses that replicate either in humans or in plants. Regarding human viruses, three families were most abundant and frequent in the oropharynx: Herpesviridae, Picornaviridae, and Reoviridae; in fecal samples, four virus families predominated: Caliciviridae, Picornaviridae, Reoviridae, and Anelloviridae. Both niches showed a high abundance of plant viruses of the family Virgaviridae. Differences in the frequency and abundance of sequence reads and diversity of virus species were observed in both niches and throughout the year of study, with some viruses already present in the first months of life. Our results suggest that the children's virome is dynamic and likely shaped by the environment, feeding, and age. Moreover, composition analysis suggests that the virome composition is mostly individual. Whether this constant exposition to different viruses has a long-term impact on children's health or development remains to be studied.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Barbosa FAS, Brait LAS, Coutinho FH, et al (2023)

Ecological landscape explains aquifers microbial structure.

The Science of the total environment, 862:160822.

Aquifers have significant social, economic, and ecological importance. They supply 30 % of the freshwater for human consumption worldwide, including agricultural and industrial use. Despite aquifers' importance, the relationships between aquifer categories and their inhabiting microbial communities are still unknown. Characterizing variations within microbial communities' function and taxonomy structure at different aquifers could give a panoramic view of patterns that may enable the detection and prediction of environmental impact caused by multiple sources. Using publicly available shotgun metagenomic datasets, we examined whether soil properties, land use, and climate variables would have a more significant influence on the taxonomy and functional structure of the microbial communities than the ecological landscapes of the aquifer (i.e., Karst, Porous, Saline, Geyser, and Porous Contaminated). We found that these categories are stronger predictors of microbial communities' structure than geographical localization. In addition, our results show that microbial richness and dominance patterns are the opposite of those found in multicellular life, where extreme habitats harbour richer functional and taxonomic microbial communities. We found that low-abundant and recently described candidate taxa, such as the chemolithoautotrophic genus Candidatus Altiarcheum and the Candidate phylum Parcubacteria, are the main contributors to aquifer microbial communities' dissimilarities. Genes related to gram-negative bacteria proteins, cell wall structures, and phage activity were the primary contributors to aquifer microbial communities' dissimilarities among the aquifers' ecological landscapes. The results reported in the present study highlight the utility of using ecological landscapes for investigating aquifer microbial communities. In addition, we suggest that functions played by recently described and low abundant bacterial groups need further investigation once they might affect water quality, geochemical cycles, and the effects of anthropogenic disturbances such as pollution and climatic events on aquifers.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Nie S, Mo S, Gao T, et al (2023)

Coupling effects of nitrate reduction and sulfur oxidation in a subtropical marine mangrove ecosystem with Spartina alterniflora invasion.

The Science of the total environment, 862:160930.

The mangrove ecosystem has a high nitrate reduction capacity, which significantly alleviates severe nitrogen pollution. However, current research on nitrate reduction mechanisms in the mangrove ecosystem is limited. Furthermore, Spartina alterniflora invasion has disrupted the balance of the mangrove ecosystem and the effect of S. alterniflora on nitrate reduction has not yet been fully elucidated. Nitrate reduction was comprehensively investigated in a subtropical mangrove ecosystem in this study, which has been invaded by S. alterniflora for 40 years. Results showed that S. alterniflora significantly increased the relative and absolute abundance of nitrate reduction genes, especially nirS (nitrite reductase), in the mangrove ecosystem. Dissimilatory nitrate reduction to ammonium was the main pathway of nitrate reduction in the mangrove ecosystem. Nitrate reduction was mainly performed by Desulfobacterales and occurred in the shallow layers (0-10 cm) of mangrove sediments. A strong positive correlation was found between nitrate reduction and sulfur oxidation (especially sulfide oxidation), and the sulfide content was significantly positively correlated with the relative abundance of nitrate reduction genes. Moreover, 207 metagenomic assembled genomes (MAGs) were constructed, including 50 MAGs with high numbers (≥ 10) of nitrate reduction genes. This finding indicates that the dominant microbes had strong nitrate reduction potential in mangrove sediments. Our findings highlight the impact of S. alterniflora invasion on nitrate reduction in a subtropical marine mangrove ecosystem. This study provides new insights into our understanding of nitrogen pollution control and contributes to the exploration of new nitrogen-degrading microbes in mangrove ecosystems.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Suryaletha K, Savithri AV, Nayar SA, et al (2022)

Demystifying Bacteriocins of Human Microbiota by Genome Guided Prospects: An Impetus to Rekindle the Antimicrobial Research.

Current protein & peptide science, 23(12):811-822.

The human microbiome is a reservoir of potential bacteriocins that can counteract multidrug resistant bacterial pathogens. Unlike antibiotics, bacteriocins selectively inhibit a spectrum of competent bacteria and are said to safeguard gut commensals, reducing the chance of dysbiosis. Bacteriocinogenic probiotics or bacteriocins of human origin will be more pertinent in human physiological conditions for therapeutic applications to act against invading pathogens. Recent advancement in the omics approach enables the mining of diverse and novel bacteriocins by identifying biosynthetic gene clusters from the human microbial genome, pangenome or shotgun metagenome, which is a breakthrough in the discovery line of novel bacteriocins. This review summarizes the most recent trends and therapeutic potential of bacteriocins of human microbial origin, the advancement in the in silico algorithms and databases in the discovery of novel bacteriocin, and how to bridge the gap between the discovery of bacteriocin genes from big datasets and their in vitro production. Besides, the later part of the review discussed the various impediments in their clinical applications and possible solution to bring them into the frontline therapeutics to control infections, thereby meeting the challenges of global antimicrobial resistance.

RevDate: 2023-01-19
CmpDate: 2023-01-19

Han Y, Xu J, Yan Y, et al (2022)

Dynamics of the gut microbiota in rats after hypobaric hypoxia exposure.

PeerJ, 10:e14090.

BACKGROUND: Gut microbiota plays an important role in host health and is influenced by multiple factors. Hypobaric hypoxia usually existing at high altitude conditions can adversely affect normal physiological functions. However, the dynamic changes of gut microbiota influenced by hypobaric hypoxia have not been elucidated.

METHODS: In this study, we collected fecal samples from seven rats at 14 time points from entering the hypobaric chamber (eight time points) to leaving the chamber (six time points) and five rats served as normoxic controls. Metagenome sequencing was performed on all samples and the dynamics of taxa and functions were analyzed.

RESULTS: We found that the α-diversity was changed in the first 5 days after entering or leaving the hypobaric chamber. The β-diversity analysis revealed that gut microbiota structure was significantly separated among 14 time points. After entering the chamber, the relative abundance of Bacteroides decreased and the most abundant genus turned into Prevotella. The abundance of Firmicutes and Bacteroidetes showed an opposite trend and both have a significant change within 5 days after entering or leaving the hypobaric hypoxia chamber. Some obligate anaerobic bacteria belonging to Desulfovibrio and Alistipes were significantly enriched after entering the chamber for 5 weeks, whereas Probiotics like Bifidobacterium and Lactococcus, and short-chain fatty acids producers like Butyrivibrio and Pseudobutyrivibrio were significantly enriched after leaving the chamber for 3 weeks. Microbial functions like 'Two-component regulatory system', 'beta-carotene biosynthesis' and 'Fatty acid biosynthesis' were significantly enriched after entering the chamber for 5 weeks. Hypobaric hypoxia conditions could deeply affect the diversity and structure of gut microbiota. The alterations of abundance of dominant taxa (Firmicutes and Bacteroidetes), increased anaerobes and decreased probiotics induced by hypobaric hypoxia conditions might affect the host health.

RevDate: 2023-01-18

Fernandes-Martins MC, Colman DR, ES Boyd (2023)

Relationships between fluid mixing, biodiversity, and chemosynthetic primary productivity in Yellowstone hot springs.

Environmental microbiology [Epub ahead of print].

The factors that influence biodiversity and productivity of hydrothermal ecosystems are not well understood. Here we investigate the relationship between fluid mixing, biodiversity, and chemosynthetic primary productivity in three co-localized hot springs (RSW, RSN, and RSE) in Yellowstone National Park that have different geochemistry. All three springs are sourced by reduced hydrothermal fluid, but RSE and RSN receive input of vapor phase gas and oxidized groundwaters, with input of both being substantially higher in RSN. Metagenomic sequencing revealed that communities in RSN were more biodiverse than those of RSE and RSW in all dimensions evaluated. Microcosm activity assays indicate that rates of dissolved inorganic carbon uptake were also higher in RSN than in RSE and RSW. Together, these results suggest that increased mixing of reduced volcanic fluid with oxidized fluids generates additional niche space capable of supporting increasingly biodiverse communities that are more productive. These results provide insight into the factors that generate and maintain chemosynthetic biodiversity in hydrothermal systems and that influence the distribution, abundance, and diversity of microbial life in communities supported by chemosynthesis. These factors may also extend to other ecosystems not supported by photosynthesis, including the vast subterranean biosphere and biospheres beneath ice sheets and glaciers. This article is protected by copyright. All rights reserved.

RevDate: 2023-01-18

Petrone ME, Holmes EC, E Harvey (2023)

Through an ecological lens: An ecosystem-based approach to zoonotic risk assessment: An ecosystem-based approach to zoonotic risk assessment.

EMBO reports [Epub ahead of print].

Public health strategies to mitigate the emergence of novel pathogenic viruses should implement longitudinal metagenomic surveillance of ecosystems experiencing biodiversity changes to identify generalist viruses.

RevDate: 2023-01-17
CmpDate: 2023-01-17

Maki KA, Wolff B, Varuzza L, et al (2023)

Multi-amplicon microbiome data analysis pipelines for mixed orientation sequences using QIIME2: Assessing reference database, variable region and pre-processing bias in classification of mock bacterial community samples.

PloS one, 18(1):e0280293.

Microbiome research relies on next-generation sequencing and on downstream data analysis workflows. Several manufacturers have introduced multi-amplicon kits for microbiome characterization, improving speciation, but present unique challenges for analysis. The goal of this methodology study was to develop two analysis pipelines specific to mixed-orientation reads from multi-hypervariable (V) region amplicons. A secondary aim was to assess agreement with expected abundance, considering database and variable region. Mock community sequence data (n = 41) generated using the Ion16S™ Metagenomics Kit and Ion Torrent Sequencing Platform were analyzed using two workflows. Amplicons from V2, V3, V4, V6-7, V8 and V9 were deconvoluted using a specialized plugin based on CutPrimers. A separate workflow using Cutadapt is also presented. Three reference databases (Ribosomal Database Project, Greengenes and Silva) were used for taxonomic assignment. Bray-Curtis, Euclidean and Jensen-Shannon distance measures were used to evaluate overall annotation consistency, and specific taxon agreement was determined by calculating the ratio of observed to expected relative abundance. Reads that mapped to regions V2-V9 varied for both CutPrimers and Cutadapt-based methods. Within the CutPrimers-based pipeline, V3 amplicons had the best agreement with the expected distribution, tested using global distance measures, while V9 amplicons had the worst agreement. Accurate taxonomic annotation varied by genus-level taxon and V region analyzed. For the first time, we present a microbiome analysis pipeline that employs a specialized plugin to allow microbiome researchers to separate multi-amplicon data from the Ion16S Metagenomics Kit into V-specific reads. We also present an additional analysis workflow, modified for Ion Torrent mixed orientation reads. Overall, the global agreement of amplicons with the expected mock community abundances differed across V regions and reference databases. Benchmarking data should be referenced when planning a microbiome study to consider these biases related to sequencing and data analysis for multi-amplicon sequencing kits.

RevDate: 2023-01-17
CmpDate: 2023-01-17

Kibegwa FM, Bett RC, Gachuiri CK, et al (2023)

Diversity and functional analysis of rumen and fecal microbial communities associated with dietary changes in crossbreed dairy cattle.

PloS one, 18(1):e0274371.

The objective of this study was to investigate the effect of varying roughage and concentrate proportions, in diet of crossbreed dairy cattle, on the composition and associated functional genes of rumen and fecal microbiota. We also explored fecal samples as a proxy for rumen liquor samples. Six crossbred dairy cattle were reared on three diets with an increasing concentrate and reducing roughage amount in three consecutive 10-day periods. After each period, individual rumen liquor and fecal samples were collected and analyzed through shotgun metagenomic sequencing. Average relative abundance of identified Operational Taxonomic Units (OTU) and microbial functional roles from all animals were compared between diets and sample types (fecal and rumen liquor). Results indicated that dietary modifications significantly affected several rumen and fecal microbial OTUs. In the rumen, an increase in dietary concentrate resulted in an upsurge in the abundance of Proteobacteria, while reducing the proportions of Bacteroidetes and Firmicutes. Conversely, changes in microbial composition in fecal samples were not consistent with dietary modification patterns. Microbial functional pathway classification identified that carbohydrate metabolism and protein metabolism pathways dominated microbial roles. Assessment of dietary effects on the predicted functional roles of these microbiota revealed that a high amount of dietary concentrate resulted in an increase in central carbohydrate metabolism and a corresponding reduction in protein synthesis. Moreover, we identified several microbial stress-related responses linked to dietary changes. Bacteroides and Clostridium genera were the principal hosts of these microbial functions. Therefore, the roughage to concentrate proportion has more influence on the microbial composition and microbial functional genes in rumen samples than fecal samples. As such, we did not establish a significant relationship between the rumen and fecal metagenome profiles, and the rumen and fecal microbiota from one animal did not correlate more than those from different animals.

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ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

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When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

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Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

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With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).

Timelines

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Biographies

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Selected Bibliographies

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