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Bibliography on: Symbiosis

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ESP: PubMed Auto Bibliography 27 Nov 2020 at 01:53 Created: 

Symbiosis

Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

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RevDate: 2020-11-26

Maity S, K Ambatipudi (2020)

Mammary microbial dysbiosis leads to the zoonosis of bovine mastitis: A one-health perspective.

FEMS microbiology ecology pii:6006870 [Epub ahead of print].

Bovine mastitis is a prototypic emerging and reemerging bacterial disease that results in cut-by-cut torture to animals, public health, and the global economy. Pathogenic mastitis causing microbes have overcome a series of hierarchical barriers resulting in the zoonotic transmission from bovines to humans either by proximity or remotely through milk and meat. The disease control is challenging and has been attributed to faulty surveillance systems to monitor their emergence at the human-animal interface. The complex interaction between the pathogens, the hidden pathobionts, and commensals of the bovine mammary gland that create a menace during mastitis remains unexplored. Here, we review the zoonotic potential of these pathogens with a primary focus on understanding the interplay between the host immunity, mammary ecology, and the shift from symbiosis to dysbiosis. We also address the pros and cons of current management strategies and the extent of the success in implementing the One-Health approach to keep these pathogens at bay.

RevDate: 2020-11-26

Aichelman HE, DJ Barshis (2020)

Adaptive divergence, neutral panmixia, and algal symbiont population structure in the temperate coral Astrangia poculata along the Mid-Atlantic United States.

PeerJ, 8:e10201 pii:10201.

Astrangia poculata is a temperate scleractinian coral that exists in facultative symbiosis with the dinoflagellate alga Breviolum psygmophilum across a range spanning the Gulf of Mexico to Cape Cod, Massachusetts. Our previous work on metabolic thermal performance of Virginia (VA) and Rhode Island (RI) populations of A. poculata revealed physiological signatures of cold (RI) and warm (VA) adaptation of these populations to their respective local thermal environments. Here, we used whole-transcriptome sequencing (mRNA-Seq) to evaluate genetic differences and identify potential loci involved in the adaptive signature of VA and RI populations. Sequencing data from 40 A. poculata individuals, including 10 colonies from each population and symbiotic state (VA-white, VA-brown, RI-white, and RI-brown), yielded a total of 1,808 host-associated and 59 algal symbiont-associated single nucleotide polymorphisms (SNPs) post filtration. Fst outlier analysis identified 66 putative high outlier SNPs in the coral host and 4 in the algal symbiont. Differentiation of VA and RI populations in the coral host was driven by putatively adaptive loci, not neutral divergence (Fst = 0.16, p = 0.001 and Fst = 0.002, p = 0.269 for outlier and neutral SNPs respectively). In contrast, we found evidence of neutral population differentiation in B. psygmophilum (Fst = 0.093, p = 0.001). Several putatively adaptive host loci occur on genes previously associated with the coral stress response. In the symbiont, three of four putatively adaptive loci are associated with photosystem proteins. The opposing pattern of neutral differentiation in B. psygmophilum, but not the A. poculata host, reflects the contrasting dynamics of coral host and algal symbiont population connectivity, dispersal, and gene by environment interactions.

RevDate: 2020-11-25

Mortezaee K (2020)

Redox tolerance and metabolic reprogramming in solid tumors.

Cell biology international [Epub ahead of print].

Tumor cells are needed to cope with the host environment in order to maintain their survival and keep growing in hard conditions. This infers that tumors must acquire characteristics more potent than what seen for normal tissue cells, without which they are condemned to disruption. As for example, cancer cells have more potent redox tolerance compared to normal cells, which is due to their high adaptation to the oxidative crisis. In addition, increased demand for bioenergetics and biosynthesis can cause a rise of nutrient uptake in tumors. Utilizing nutrients in low nutrient conditions infers that tumors are also equipped with adaptive metabolic processes. Switching the metabolic demands toward glucose consumption upon exposure to the hypoxic TME, or changing toward using other sources when there is an over-consumption of glucose in the tumor area are examples of fitness metabolic systems in tumors. In fact, cancer cells in cooperation with their nearby stroma (in a process called metabolic coupling) can reprogram their metabolic systems in their favor. This infers the high importance of stroma for meeting the metabolic demands of a growing tumor, an example in this context is the metabolic symbiosis between cancer associated fibroblasts (CAFs) with cancer cells. The point is that redox tolerance and metabolic reprogramming are inter-related, and that, without a doubt, disruption of redox tolerance systems by transient exposure to either oxidative or antioxidative loading, or targeting metabolic rewiring by modulation of tumor glucose availability, controlling tumor/stroma interactions, etc. can be effective from therapeutic window. This article is protected by copyright. All rights reserved.

RevDate: 2020-11-25

Ahmad F, Yang GY, Liang SY, et al (2020)

Multipartite symbioses in fungus-growing termites (Blattodea: Termitidae, Macrotermitinae) for the degradation of lignocellulose.

Insect science [Epub ahead of print].

Fungus-growing termites are among the most successful herbivorous animals and improve crop productivity and soil fertility. A range of symbiotic organisms can be found inside their nests. However, interactions of termites with these symbionts are poorly understood. This review provides detailed information on the role of multipartite symbioses (between termitophiles, termites, fungi, and bacteria) in fungus-growing termites for lignocellulose degradation. The specific functions of each component in the symbiotic system are also discussed. Based on previous studies, we argue that the enzymatic contribution from the host, fungus, and bacteria greatly facilitates the decomposition of complex polysaccharide plant materials. The host-termitophile interaction protects the termite nest from natural enemies and maintains the stability of the microenvironment inside the colony. This article is protected by copyright. All rights reserved.

RevDate: 2020-11-25

Gorman LM, Wilkinson SP, Kitchen SA, et al (2020)

Phylogenetic analysis of cell-cycle regulatory proteins within the Symbiodiniaceae.

Scientific reports, 10(1):20473 pii:10.1038/s41598-020-76621-1.

In oligotrophic waters, cnidarian hosts rely on symbiosis with their photosynthetic dinoflagellate partners (family Symbiodiniaceae) to obtain the nutrients they need to grow, reproduce and survive. For this symbiosis to persist, the host must regulate the growth and proliferation of its symbionts. One of the proposed regulatory mechanisms is arrest of the symbiont cell cycle in the G1 phase, though the cellular mechanisms involved remain unknown. Cell-cycle progression in eukaryotes is controlled by the conserved family of cyclin-dependent kinases (CDKs) and their partner cyclins. We identified CDKs and cyclins in different Symbiodiniaceae species and examined their relationship to homologs in other eukaryotes. Cyclin proteins related to eumetazoan cell-cycle-related cyclins A, B, D, G/I and Y, and transcriptional cyclin L, were identified in the Symbiodiniaceae, alongside several alveolate-specific cyclin A/B proteins, and proteins related to protist P/U-type cyclins and apicomplexan cyclins. The largest expansion of Symbiodiniaceae cyclins was in the P/U-type cyclin groups. Proteins related to eumetazoan cell-cycle-related CDKs (CDK1) were identified as well as transcription-related CDKs. The largest expansion of CDK groups was, however, in alveolate-specific groups which comprised 11 distinct CDK groups (CDKA-J) with CDKB being the most widely distributed CDK protein. As a result of its phylogenetic position, conservation across Symbiodiniaceae species, and the presence of the canonical CDK motif, CDKB emerged as a likely candidate for a Saccharomyces cerevisiae Cdc28/Pho85-like homolog in Symbiodiniaceae. Similar to cyclins, two CDK-groups found in Symbiodiniaceae species were solely associated with apicomplexan taxa. A comparison of Breviolum minutum CDK and cyclin gene expression between free-living and symbiotic states showed that several alveolate-specific CDKs and two P/U-type cyclins exhibited altered expression in hospite, suggesting that symbiosis influences the cell cycle of symbionts on a molecular level. These results highlight the divergence of Symbiodiniaceae cell-cycle proteins across species. These results have important implications for host control of the symbiont cell cycle in novel cnidarian-dinoflagellate symbioses.

RevDate: 2020-11-25

Hammer TJ, Dickerson JC, McMillan WO, et al (2020)

Heliconius Butterflies Host Characteristic and Phylogenetically Structured Adult-Stage Microbiomes.

Applied and environmental microbiology, 86(24):.

Lepidoptera (butterflies and moths) are diverse and ecologically important, yet we know little about how they interact with microbes as adults. Due to metamorphosis, the form and function of their adult-stage microbiomes might be very different from those of microbiomes in the larval stage (caterpillars). We studied adult-stage microbiomes of Heliconius and closely related passion-vine butterflies (Heliconiini), which are an important model system in evolutionary biology. To characterize the structure and dynamics of heliconiine microbiomes, we used field collections of wild butterflies, 16S rRNA gene sequencing, quantitative PCR, and shotgun metagenomics. We found that Heliconius butterflies harbor simple and abundant bacterial communities that are moderately consistent among conspecific individuals and over time. Heliconiine microbiomes also exhibited a strong signal of the host phylogeny, with a major distinction between Heliconius and other butterflies. These patterns were largely driven by differing relative abundances of bacterial phylotypes shared among host species and genera, as opposed to the presence or absence of host-specific phylotypes. We suggest that the phylogenetic structure in heliconiine microbiomes arises from conserved host traits that differentially filter microbes from the environment. While the relative importance of different traits remains unclear, our data indicate that pollen feeding (unique to Heliconius) is not a primary driver. Using shotgun metagenomics, we also discovered trypanosomatids and microsporidia to be prevalent in butterfly guts, raising the possibility of antagonistic interactions between eukaryotic parasites and colocalized gut bacteria. Our discovery of characteristic and phylogenetically structured microbiomes provides a foundation for tests of adult-stage microbiome function, a poorly understood aspect of lepidopteran biology.IMPORTANCE Many insects host microbiomes with important ecological functions. However, the prevalence of this phenomenon is unclear because in many insect taxa, microbiomes have been studied in only part of the life cycle, if at all. A prominent example is butterflies and moths, in which the composition and functional role of adult-stage microbiomes are largely unknown. We comprehensively characterized microbiomes in adult passion-vine butterflies. Butterfly-associated bacterial communities are generally abundant in guts, consistent within populations, and composed of taxa widely shared among hosts. More closely related butterflies harbor more similar microbiomes, with the most dramatic shift in microbiome composition occurring in tandem with a suite of ecological and life history traits unique to the genus Heliconius Butterflies are also frequently infected with previously undescribed eukaryotic parasites, which may interact with bacteria in important ways. These findings advance our understanding of butterfly biology and insect-microbe interactions generally.

RevDate: 2020-11-25
CmpDate: 2020-11-25

Wang Z, Li H, Zhou X, et al (2020)

Comparative characterization of microbiota between the sibling species of tea geometrid moth Ectropis obliqua Prout and E. grisescens Warren.

Bulletin of entomological research, 110(6):684-693.

For a wide range of insect species, the microbiota has potential roles in determining host developmental programme, immunity and reproductive biology. The tea geometrid moths Ectropis obliqua and E. grisescens are two closely related species that mainly feed on tea leaves. Although they can mate, infertile hybrids are produced. Therefore, these species provide a pair of model species for studying the molecular mechanisms of microbiotal involvement in host reproductive biology. In this study, we first identified and compared the compositions of microbiota between these sibling species, revealing higher microbiotal diversity for E. grisescens. The microbiota of E. obliqua mainly comprised the phyla Firmicutes, Proteobacteria and Cyanobacteria, whereas that of E. grisescens was dominated by Proteobacteria, Actinobacteria and Firmicutes. At the genus level, the dominant microbiota of E. grisescens included Wolbachia, Enterobacter and Pseudomonas and that of E. obliqua included Melissococcus, Staphylococcus and Enterobacter. Furthermore, we verified the rate of Wolbachia to infect 80 samples from eight different geographical populations, and the results supported that only E. grisescens harboured Wolbachia. Taken together, our findings indicate significantly different microbiotal compositions for E. obliqua and E. grisescens, with Wolbachia possibly being a curial factor influencing the reproductive isolation of these species. This study provides new insight into the mechanisms by which endosymbiotic bacteria, particularly Wolbachia, interact with sibling species.

RevDate: 2020-11-25
CmpDate: 2020-11-25

Ramoneda J, Le Roux JJ, Frossard E, et al (2020)

Experimental assembly reveals ecological drift as a major driver of root nodule bacterial diversity in a woody legume crop.

FEMS microbiology ecology, 96(6):.

Understanding how plant-associated microbial communities assemble and the role they play in plant performance are major goals in microbial ecology. For nitrogen-fixing rhizobia, community assembly is generally driven by host plant selection and soil conditions. Here, we aimed to determine the relative importance of neutral and deterministic processes in the assembly of bacterial communities of root nodules of a legume shrub adapted to extreme nutrient limitation, rooibos (Aspalathus linearis Burm. Dahlgren). We grew rooibos seedlings in soil from cultivated land and wild habitats, and mixtures of these soils, sampled from a wide geographic area, and with a fertilization treatment. Bacterial communities were characterized using next generation sequencing of part of the nodA gene (i.e. common to the core rhizobial symbionts of rooibos), and part of the gyrB gene (i.e. common to all bacterial taxa). Ecological drift alone was a major driver of taxonomic turnover in the bacterial communities of root nodules (62.6% of gyrB communities). In contrast, the assembly of core rhizobial communities (genus Mesorhizobium) was driven by dispersal limitation in concert with drift (81.1% of nodA communities). This agrees with a scenario of rooibos-Mesorhizobium specificity in spatially separated subpopulations, and low host filtering of other bacteria colonizing root nodules in a stochastic manner.

RevDate: 2020-11-24

Youseif SH, Abd El-Megeed FH, Mohamed AH, et al (2020)

Diverse Rhizobium strains isolated from root nodules of Trifolium alexandrinum in Egypt and symbiovars.

Systematic and applied microbiology, 44(1):126156 pii:S0723-2020(20)30111-9 [Epub ahead of print].

Berseem clover (T. alexandrinum) is the main forage legume crop used as animal feed in Egypt. Here, eighty rhizobial isolates were isolated from root nodules of berseem clover grown in different regions in Egypt and were grouped by RFLP-16S rRNA ribotyping. Representative isolates were characterized using phylogenetic analyses of the 16S rRNA, rpoB, glnA, pgi, and nodC genes. We also investigated the performance of these isolates using phenotypic tests and nitrogen fixation efficiency assays. The majority of strains (<90%) were closely related to Rhizobium aegyptiacum and Rhizobium aethiopicum and of the remaining strains, six belonged to the Rhizobium leguminosarum genospecies complex and only one strain was assigned to Agrobacterium fabacearum. Despite their heterogeneous chromosomal background, most of the strains shared nodC gene alleles corresponding to symbiovar trifolii. Some of the strains closely affiliated to R. aegyptiacum and R. aethiopicum had superior nodulation and nitrogen fixation capabilities in berseem clover, compared to the commercial inoculant (Okadein®) and N-added treatments. R. leguminosarum strain NGB-CR 17 that harbored a nodC allele typical of symbiovar viciae, was also able to form an effective symbiosis with clover. Two strains with nodC alleles of symbiovar trifolii, R. aegyptiacum strains NGB-CR 129 and 136, were capable of forming effective nodules in Phaseolus vulgaris in axenic greenhouse conditions. This adds the symbiovar trifolii which is well-established in the Egyptian soils to the list of symbiovars that form nodules in P. vulgaris.

RevDate: 2020-11-24

Li Q, Kuo YW, Lin KH, et al (2020)

Piriformospora indica colonization increases the growth, development, and herbivory resistance of sweet potato (Ipomoea batatas L.).

Plant cell reports pii:10.1007/s00299-020-02636-7 [Epub ahead of print].

KEY MESSAGE: Piriformospora indica symbiosis promoted the growth and photosynthesis, and simultaneously enhanced the resistance against insect herbivory by regulating sporamin-dependent defense in sweet potato. Piriformospora indica (P. indica), a versatile endophytic fungus, promotes the growth and confers resistance against multiple stresses by root colonization in plant hosts. In this study, the effects of P. indica colonization on the growth, physiological change, and herbivore resistance of leaf-vegetable sweet potato cultivar were investigated. P. indica symbiosis significantly improved the biomass in both above- and under-ground parts of sweet potato plants. In comparison with the non-colonized plants, the content of photosynthetic pigments and the efficiency of photosynthesis were increased in P. indica-colonized sweet potato plants. Further investigation showed that the activity of catalase was enhanced in both leaves and roots of sweet potato plants after colonization, but ascorbate peroxidase, peroxidase, and superoxide dismutase were not enhanced. Furthermore, the interaction between P. indica and sweet potato plants also showed the biological function in jasmonic acid (JA)-mediated defense. The plants colonized by P. indica had greatly increased JA accumulation and defense gene expressions, including IbNAC1, IbbHLH3, IbpreproHypSys, and sporamin, leading to elevated trypsin inhibitory activity, which was consistent with a reduced Spodoptera litura performance when larvae fed on the leaves of P. indica-colonized sweet potato plants. The root symbiosis of P. indica is helpful for the plant promoting growth and development and has a strong function as resistance inducers against herbivore attack in sweet potato cultivation by regulating sporamin-dependent defense.

RevDate: 2020-11-24

Chen M, Bruisson S, Bapaume L, et al (2020)

VAPYRIN attenuates defence by repressing PR gene induction and localised lignin accumulation during arbuscular mycorrhizal symbiosis of Petunia hybrida.

The New phytologist [Epub ahead of print].

The intimate association of host and fungus in arbuscular mycorrhizal (AM) symbiosis can potentially trigger induction of host defence mechanisms against the fungus, implying that successful symbiosis requires suppression of defence. We addressed this phenomenon by using AM-defective vapyrin (vpy) mutants in Petunia hybrida, including a new allele (vpy-3) with a transposon insertion close to the ATG start codon. We explore whether abortion of fungal infection in vpy mutants is associated with the induction of defence markers such as cell wall alterations, accumulation of reactive oxygen species (ROS), defence hormones, and induction of pathogenesis-related (PR) genes. We show that vpy mutants exhibit a strong resistance against intracellular colonisation, which is associated with the generation of cell wall appositions (papillae) with lignin impregnation at fungal entry sites, while no accumulation of defence hormones, ROS, or callose was observed. Systematic analysis of PR gene expression revealed that several PR genes are induced in mycorrhizal roots of the wild type, and even more in vpy plants. Some PR genes are induced exclusively in vpy mutants. Our results suggest that VPY is involved in avoiding or suppressing the induction of a cellular defence syndrome that involves localised lignin deposition and PR gene induction.

RevDate: 2020-11-24

Virdi JK, P Pethe (2020)

Biomaterials Regulate Mechanosensors YAP/TAZ in Stem Cell Growth and Differentiation.

Tissue engineering and regenerative medicine pii:10.1007/s13770-020-00301-4 [Epub ahead of print].

Tissue-resident stem cells are surrounded by a microenvironment known as 'stem cell niche' which is specific for each stem cell type. This niche comprises of cell-intrinsic and -extrinsic factors like biochemical and biophysical signals, which regulate stem cell characteristics and differentiation. Biochemical signals have been thoroughly studied however, the effect of biophysical signals on stem cell regulation is yet to be completely understood. Biomaterials have aided in addressing this issue since they can provide a defined and tuneable microenvironment resembling in vivo conditions. We review various biomaterials used in many studies which have shown a connection between biomaterial-generated mechanical signals and alteration in stem cell behaviour. Researchers probed to understand the mechanism of mechanotransduction and reported that the signals from the extracellular matrix regulate a transcription factor yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ), which is a downstream-regulator of the Hippo pathway and it transduces the mechanical signals inside the nucleus. We highlight the role of the YAP/TAZ as mechanotransducers in stem cell self-renewal and differentiation in response to substrate stiffness, also the possibility of mechanobiology as the emerging field of regenerative medicines and three-dimensional tissue printing.

RevDate: 2020-11-24

Hu H, Zakharov PN, Peterson OJ, et al (2020)

Cytocidal macrophages in symbiosis with CD4 and CD8 T cells cause acute diabetes following checkpoint blockade of PD-1 in NOD mice.

Proceedings of the National Academy of Sciences of the United States of America pii:2019743117 [Epub ahead of print].

Autoimmune diabetes is one of the complications resulting from checkpoint blockade immunotherapy in cancer patients, yet the underlying mechanisms for such an adverse effect are not well understood. Leveraging the diabetes-susceptible nonobese diabetic (NOD) mouse model, we phenocopy the diabetes progression induced by programmed death 1 (PD-1)/PD-L1 blockade and identify a cascade of highly interdependent cellular interactions involving diabetogenic CD4 and CD8 T cells and macrophages. We demonstrate that exhausted CD8 T cells are the major cells that respond to PD-1 blockade producing high levels of IFN-γ. Most importantly, the activated T cells lead to the recruitment of monocyte-derived macrophages that become highly activated when responding to IFN-γ. These macrophages acquire cytocidal activity against β-cells via nitric oxide and induce autoimmune diabetes. Collectively, the data in this study reveal a critical role of macrophages in the PD-1 blockade-induced diabetogenesis, providing new insights for the understanding of checkpoint blockade immunotherapy in cancer and infectious diseases.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Marqués-Gálvez JE, Navarro-Ródenas A, Peguero-Pina JJ, et al (2020)

Elevated atmospheric CO2 modifies responses to water-stress and flowering of Mediterranean desert truffle mycorrhizal shrubs.

Physiologia plantarum, 170(4):537-549.

Predicted increases in atmospheric concentration of carbon dioxide (CO2) coupled with increased temperatures and drought are expected to strongly influence the development of most of the plant species in the world, especially in areas with high risk of desertification like the Mediterranean basin. Helianthemum almeriense is an ecologically important Mediterranean shrub with an added interest because it serves as the host for the Terfezia claveryi mycorrhizal fungus, which is a desert truffle with increasingly commercial interest. Although both plant and fungi are known to be well adapted to dry conditions, it is still uncertain how the increase in atmospheric CO2 will influence them. In this article we have addressed the physiological responses of H. almeriense × T. claveryi mycorrhizal plants to increases in atmospheric CO2 coupled with drought and high vapor pressure deficit. This work reports one of the few estimations of mesophyll conductance in a drought deciduous Mediterranean shrub and evaluates its role in photosynthesis limitation. High atmospheric CO2 concentrations help desert truffle mycorrhizal plants to cope with the adverse effects of progressive drought during Mediterranean springs by improving carbon net assimilation, intrinsic water use efficiency and dispersal of the species through increased flowering events.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Rocha EA, MDE Fellowes (2020)

Urbanisation alters ecological interactions: Ant mutualists increase and specialist insect predators decrease on an urban gradient.

Scientific reports, 10(1):6406.

The modification of habitats in urban areas is thought to alter patterns of species interactions, by filtering specialist species and those at higher trophic levels. However, empirical studies addressing these hypotheses remain limited in scope and number. This work investigates (1) how main urban land uses affect predator-prey and mutualistic interactions, and (2) how specialist and generalist predators respond to size and availability of urban green spaces. In a large town in the UK, experimental colonies of ant-attended Black bean aphid Aphis fabae and non-ant-attended Pea aphid Acyrthosiphon pisum were monitored over two years. Ants were more frequently found in highly urbanised sites; however mutualistic ants were also more often encountered when the habitat was more plant diverse. Aphids were not affected by urban land uses, but A. fabae numbers were positively related to the presence of mutualists, and so indirectly affected by urbanisation. Predators were the only group negatively affected by increased urbanisation, and specialist species were positively related to increased proportion of urban green areas within the habitats. While this work supports the hypothesis that specialist predators are negatively affected by urbanisation, we also show that a fundamental ecological interaction, mutualism, is affected by urbanisation.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Perrin-Guyomard A, Jouy E, Urban D, et al (2020)

Decrease in fluoroquinolone use in French poultry and pig production and changes in resistance among E. coli and Campylobacter.

Veterinary microbiology, 243:108637.

This paper presents the impact on antimicrobial resistance (AMR) in poultry and pig bacteria of the French EcoAntibio plan, a public policy to reduce antimicrobial use in animals. The analysis was performed using sales data of veterinary antimicrobials and AMR data from bacteria obtained at slaughterhouse and from diseased animals. From 2011-2018, fluoroquinolones exposure decreased by 71.5 % for poultry and 89.7 % for pigs. For Campylobacter jejuni isolated from broilers at slaughterhouses, ciprofloxacin resistance increased from 51 % in 2010 to 63 % in 2018, whereas for turkeys the percentages varied from 56 % in 2014 to 63 % in 2018. For commensal E. coli isolated from the caecal content of broilers at slaughterhouses, the resistance to ciprofloxacin - assessed using an epidemiological cut-off value - increased in broiler isolates from 30.7 % in 2010 to 38.1 % in 2018. In turkeys, the percentage of resistant E. coli isolates decreased from 21.3 % in 2014 to 15.2 % in 2018, whereas in pigs, it increased from 1.9 % in 2009 to 5.5 % in 2017. However, for E. coli isolated from diseased animals, when the breakpoints of 2018 were applied, resistance to fluoroquinolones significantly decreased between 2010 and 2018 from 9.0%-5.4% for broilers/hens, from 7.4 % to 3.4 % for turkeys and from 9.4 % to 3.6 % for pigs. These data show that the major, rapid decrease in the exposition to fluoroquinolones had contrasting effects on resistance in the diverse bacterial collections. Co-selection or fitness of resistant strains may explain why changes in AMR do not always closely mirror changes in use.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Dishon G, Grossowicz M, Krom M, et al (2020)

Evolutionary Traits that Enable Scleractinian Corals to Survive Mass Extinction Events.

Scientific reports, 10(1):3903.

Scleractinian "stony" corals are major habitat engineers, whose skeletons form the framework for the highly diverse, yet increasingly threatened, coral reef ecosystem. Fossil coral skeletons also present a rich record that enables paleontological analysis of coral origins, tracing them back to the Triassic (~241 Myr). While numerous invertebrate lineages were eradicated at the last major mass extinction boundary, the Cretaceous-Tertiary/K-T (66 Myr), a number of Scleractinian corals survived. We review this history and assess traits correlated with K-T mass extinction survival. Disaster-related "survival" traits that emerged from our analysis are: (1) deep water residing (>100 m); (2) cosmopolitan distributions, (3) non-symbiotic, (4) solitary or small colonies and (5) bleaching-resistant. We then compared these traits to the traits of modern Scleractinian corals, using to IUCN Red List data, and report that corals with these same survival traits have relatively stable populations, while those lacking them are presently decreasing in abundance and diversity. This shows corals exhibiting a similar dynamic survival response as seen at the last major extinction, the K-T. While these results could be seen as promising, that some corals may survive the Anthropocene extinction, they also highlight how our relatively-fragile Primate order does not possess analogous "survival" characteristics, nor have a record of mass extinction survival as some corals are capable.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Ermis H, Guven-Gulhan U, Cakir T, et al (2020)

Effect of iron and magnesium addition on population dynamics and high value product of microalgae grown in anaerobic liquid digestate.

Scientific reports, 10(1):3510 pii:10.1038/s41598-020-60622-1.

In this study, FeSO4 supplementation ranging from 0 to 4.5 mM, and MgSO4 supplementation ranging from 0 to 5.1 mM were investigated to observe the effect on the population dynamics, biochemical composition and fatty acid content of mixed microalgae grown in Anaerobic Liquid Digestate (ALD). Overall, 3.1 mM FeSO4 addition into ALD increased the total protein content 60% and led to highest biomass (1.56 g L-1) and chlorophyll-a amount (18.7 mg L-1) produced. Meanwhile, 0.4 mM MgSO4 addition increased the total carotenoid amount 2.2 folds and slightly increased the biomass amount. According to the microbial community analysis, Diphylleia rotans, Synechocystis PCC-6803 and Chlorella sorokiniana were identified as mostly detected species after confirmation with 4 different markers. The abundance of Chlorella sorokiniana and Synechocystis PCC-6803 increased almost 2 folds both in iron and magnesium addition. On the other hand, the dominancy of Diphylleia rotans was not affected by iron addition while drastically decreased (95%) with magnesium addition. This study helps to understand how the dynamics of symbiotic life changes if macro elements are added to the ALD and reveal that microalgae can adapt to adverse environmental conditions by fostering the diversity with a positive effect on high value product.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Lee SC (2020)

mSphere of Influence: the Mycobiota in Human Health and Disease.

mSphere, 5(1):.

Soo Chan Lee works in the field of medical mycology. In this mSphere of Influence article, he reflects on how "Interactions between commensal fungi and the C-type lectin receptor Dectin-1 influence colitis" (Science 336:1314-1317, 2012, https://doi.org/10.1126/science.1221789) by I. D. Iliev, V. A. Funari, K. D. Taylor, Q. Nguyen, et al., "CX3CR1+ mononuclear phagocytes control immunity to intestinal fungi" (Science 359:232-236, 2018, https://doi.org/10.1126/science.aao1503) by I. Leonardi, X. Li, A. Semon, D. Li, et al., and "The fungal mycobiome promotes pancreatic oncogenesis via activation of MBL" (Nature 574:264-267, 2019, https://doi.org/10.1038/s41586-019-1608-2) by B. Aykut, S. Pushalkar, R. Chen, Q. Li, et al. made an impact on him to study medically important fungi by providing a forum to understand the roles of fungal microbiota or mycobiota in human diseases and health.

RevDate: 2020-11-24
CmpDate: 2020-11-24

Kajla MK (2020)

Symbiotic Bacteria as Potential Agents for Mosquito Control.

Trends in parasitology, 36(1):4-7.

Xenorhabdus and Photorhabdus species are symbiotic bacteria of the insect-pathogenic soil nematodes that produce insecticidal compounds lethal to prey insects. Recently, there has been much interest in adapting these insecticidals for mosquito control. Here, I advocate the potential of Xenorhabdus/Photorhabdus as natural sources of mosquitocides (larvicides, adulticides) and feeding-deterrents.

RevDate: 2020-11-23

Guilhot R, Fellous S, JE Cohen (2020)

Yeast facilitates the multiplication of Drosophila bacterial symbionts but has no effect on the form or parameters of Taylor's law.

PloS one, 15(11):e0242692 pii:PONE-D-20-19332.

Interactions between microbial symbionts influence their demography and that of their hosts. Taylor's power law (TL)-a well-established relationship between population size mean and variance across space and time-may help to unveil the factors and processes that determine symbiont multiplications. Recent studies suggest pervasive interactions between symbionts in Drosophila melanogaster. We used this system to investigate theoretical predictions regarding the effects of interspecific interactions on TL parameters. We assayed twenty natural strains of bacteria in the presence and absence of a strain of yeast using an ecologically realistic set-up with D. melanogaster larvae reared in natural fruit. Yeast presence led to a small increase in bacterial cell numbers; bacterial strain identity largely affected yeast multiplication. The spatial version of TL held among bacterial and yeast populations with slopes of 2. However, contrary to theoretical prediction, the facilitation of bacterial symbionts by yeast had no detectable effect on TL's parameters. These results shed new light on the nature of D. melanogaster's symbiosis with yeast and bacteria. They further reveal the complexity of investigating TL with microorganisms.

RevDate: 2020-11-23

Walther C, Zumbülte S, Faerber CM, et al (2020)

Analysis of relative bacterial activity and lactate dehydrogenase gene expression of caries-associated bacteria in a site-specific natural biofilm: an ex vivo study.

Clinical oral investigations pii:10.1007/s00784-020-03691-w [Epub ahead of print].

OBJECTIVES: Detecting bacterial activity is considered a promising approach to monitor shifts from symbiosis to dysbiosis in oral microbiome. The present study aimed at investigating both the relative bacterial activity and the lactate dehydrogenase (ldh) gene expression of caries-associated bacteria in a site-specific natural biofilm.

MATERIAL AND METHODS: Sixty subjects (age, mean ± SE: 30.1 ± 1.4) were allocated to two groups: caries-free subjects (CF) or caries-active subjects (CA). CF presented one sound surface (CFS, n = 30). CA presented two donor sites: a cavitated caries lesion (CAC, n = 30) and a sound reference surface (CAS, n = 30). Real-time quantitative PCR (q-PCR) on species or genus level and total bacteria was performed targeting the 16S gene, the 16S rRNA, the ldh gene, and the ldh mRNA (increasing 16S ribosomal RNA copy numbers can function as an indicator of increased energy metabolism). As the 16S rRNA abundance represents the number of ribosomes, while the 16S gene abundance represents the number of genomes, the quotient of the relative abundances functions as a measure for the relative bacterial activity (%).

RESULTS: Both lactobacilli and S. mutans showed the highest relative bacterial activity in CAC ((mean ± SE) 218 ± 60% and 61 ± 16%, respectively) and the lowest values for both sound reference surfaces (69 ± 48%; 8 ± 3%). Significant differences were found between CAC and CAS as well as between CAC and CFS for both lactobacilli and S. mutans (p < 0.05). The ldh gene expression of lactobacilli and S. mutans only showed moderate values in CAC (1.90E+03 ± 2.11E+03; 2.08E+04 ± 4.44E+04 transcripts/μl) and CFS (2.04E+03 ± 2.74E+03; 8.16E+03 ± 6.64E+03 transcripts/μl); consequently no significant differences were detected.

Caries-associated bacteria (lactobacilli and S. mutans) showed the highest relative bacterial activity in plaque of cavitated lesions, the lowest in sound surfaces, allowing the detection of a significant activity shift in health and disease for caries-active patients. However, no significant differences in ldh gene expression could be determined.

RevDate: 2020-11-23

Nouwen N, Arrighi JF, Gully D, et al (2020)

RibBX of Bradyrhizobium ORS285 Plays an Important Role in Intracellular Persistence in Various Aeschynomene Host Plants.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

Bradyrhizobium ORS285 forms a nitrogen-fixating symbiosis with both Nod factor (NF)-dependent and NF-independent Aeschynomene spp. The Bradyrhizobium ORS285 ribBA gene encodes for a putative bifunctional enzyme with 3,4-dihydroxybutanone phosphate (3,4-DHBP) synthase and guanosine triphosphate (GTP) cyclohydrolase II activities, catalyzing the initial steps in the riboflavin biosynthesis pathway. In this study, we show that inactivating the ribBA gene does not cause riboflavin auxotrophy under free-living conditions and that, as shown for RibBAs from other bacteria, the GTP cyclohydrolase II domain has no enzymatic activity. For this reason, we have renamed the annotated ribBA as ribBX. Because we were unable to identify other ribBA or ribA and ribB homologs in the genome of Bradyrhizobium ORS285, we hypothesize that the ORS285 strain can use unconventional enzymes or an alternative pathway for the initial steps of riboflavin biosynthesis. Inactivating ribBX has a drastic impact on the interaction of Bradyrhizobium ORS285 with many of the tested Aeschynomene spp. In these Aeschynomene spp., the ORS285 ribBX mutant is able to infect the plant host cells but the intracellular infection is not maintained and the nodules senesce early. This phenotype can be complemented by reintroduction of the 3,4-DHBP synthase domain alone. Our results indicate that, in Bradyrhizobium ORS285, the RibBX protein is not essential for riboflavin biosynthesis under free-living conditions and we hypothesize that its activity is needed to sustain riboflavin biosynthesis under certain symbiotic conditions.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

RevDate: 2020-11-23

Govender Y, Chan T, Yamamoto HS, et al (2020)

The Role of Small Extracellular Vesicles in Viral-Protozoan Symbiosis: Lessons From Trichomonasvirus in an Isogenic Host Parasite Model.

Frontiers in cellular and infection microbiology, 10:591172.

The protozoan parasite Trichomonas vaginalis (TV), exclusively adapted to the human genital tract, is one of the most common sexually transmitted pathogens. Adding to the complexity of the host-pathogen interactions, the parasite harbors TV-specific endosymbiont viruses (Trichomonasvirus, TVV). It was reported that small extracellular vesicles (sEVs) released by TV play a role in host immunity; however, the role of the viral endosymbiosis in this process remained unknown. We hypothesized that the virus may offer evolutionary benefit to its protozoan host at least in part by altering the immunomodulatory properties of sEVs spreading from the site of infection to non-infected immune effector cells. We infected human vaginal epithelial cells, the natural host of the parasite, with TV natively harboring TVV and an isogenic derivative of the parasite cured from the viral infection. sEVs were isolated from vaginal cell culture 24 h post TV infection and from medium where the isogenic TV strains were cultured in the absence of the human host. sEVs from TVV-negative but not TVV-positive parasites cultured alone caused NF-κB activation and increase of IL-8 and RANTES expression by uterine endocervical cells, which provide innate immune defense at the gate to the upper reproductive tract. Similarly, mononuclear leukocytes increased their IL-8, IL-6 and TNF-α output in response to sEVs from virus-negative, but not isogenic virus-positive parasites, the latter exosomes being immunosuppressive in comparison to TV medium control. The same phenomenon of suppressed immunity induced by the TVV-positive compared to TVV-negative phenotype was seen when stimulating the leukocytes with sEVs originating from infected vaginal cultures. In addition, the sEVs from the TVV-positive infection phenotype suppressed immune signaling of a toll-like receptor ligand derived from mycoplasma, another frequent TV symbiont. Quantitative comparative proteome analysis of the secreted sEVs from virus-positive versus virus-negative TV revealed differential expression of two functionally uncharacterized proteins and five proteins involved in Zn binding, protein binding, electron transfer, transferase and catalytic activities. These data support the concept that symbiosis with viruses may provide benefit to the protozoan parasite by exploiting sEVs as a vehicle for inter-cellular communications and modifying their protein cargo to suppress host immune activation.

RevDate: 2020-11-23

Pichler G, Stöggl W, Trippel D, et al (2020)

Phytohormone release by three isolated lichen mycobionts and the effects of indole-3-acetic acid on their compatible photobionts.

Symbiosis (Philadelphia, Pa.), 82(1):95-108.

Evidence is emerging that phytohormones represent key inter-kingdom signalling compounds supporting chemical communication between plants, fungi and bacteria. The roles of phytohormones for the lichen symbiosis are poorly understood, particularly in the process of lichenization, i.e. the key events which lead free-living microalgae and fungi to recognize each other, make physical contact and start developing a lichen thallus. Here, we studied cellular and extracellularly released phytohormones in three lichen mycobionts, Cladonia grayi, Xanthoria parietina and Tephromela atra, grown on solid medium, and the effects of indole-3-acetic acid (IAA) on their respective photobionts, Asterochloris glomerata, Trebouxia decolorans, Trebouxia sp. Using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) we found that mycobionts produced IAA, salicylic acid (SA) and jasmonic acid (JA). IAA represented the most abundant phytohormone produced and released by all mycobionts, whereas SA was released by X. parietina and T. atra, and JA was released by C. grayi only. With a half-life of 5.2 days, IAA degraded exponentially in solid BBM in dim light. When IAA was exogenously offered to the mycobionts' compatible photobionts at "physiological" concentrations (as released by their respective mycobionts and accumulated in the medium over seven days), the photobionts' water contents increased up to 4.4%. Treatment with IAA had no effects on the maximum quantum yield of photosystem II, dry mass, and the contents of photosynthetic pigments and α-tocopherol of the photobionts. The data presented may be useful for designing studies aimed at elucidating the roles of phytohormones in lichens.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Patterson JD, Lafaillette F, Wöster S, et al (2020)

Impact of endophyte inoculation on the morphological identity of cultivars of Lolium perenne (L) and Festuca arundinacea (Schreb.).

Scientific reports, 10(1):7729.

Grass endophytes have been shown to confer enhanced environmental resilience to symbiont cultivars with reports of modified growth. If inoculating with an endophyte (E+) made an accession morphologically distinct from its registered endophyte free (E-) accession, there could be protection and ownership issues for testing authorities and breeders. This study investigated if, in official Plant Breeders Rights (PBR) field trials, the morphological characteristics of E+and E- accessions of perennial ryegrass and tall fescue cultivars were sufficiently modified to designate them as mutually distinct and also distinct from their definitive accessions (Def), held by the testing authorities. Testing perennial ryegrass on 17 characters at 2 sites generated 48,960 observations and for tall fescue on 9 characters at 1 site, 12,960 observations (each for 3 accessions of 4 cultivars × 60 plants × 2 growing cycles). Distinctness required a p < 0.01 difference in a single character from the combined over years analysis (COYD). A few significant differences were recorded between E- and E+accessions. Cultivar Carn E+ was smaller than Carn E- for Infloresence Length (p < 0.01) in both years but COYD analysis (p < 0.05) was insufficient to declare distinctiveness. Overall, the number of observed differences between E-/E+ accessions was less or similar to the number expected purely by chance. In contrast, comparisons between Def and E- or E+ accessions showed a number of significant differences that were substantially more numerous than expected by chance. These results showed no conclusive evidence of endophyte inclusion creating false PBR distinctions but unexpectedly, several E- and E+ accessions were distinguished from their official definitive stock.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Nacoon S, Jogloy S, Riddech N, et al (2020)

Interaction between Phosphate Solubilizing Bacteria and Arbuscular Mycorrhizal Fungi on Growth Promotion and Tuber Inulin Content of Helianthus tuberosus L.

Scientific reports, 10(1):4916 pii:10.1038/s41598-020-61846-x.

Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) could interact synergistically because PSB solubilize sparingly available phosphorous compounds into orthophosphate that AMF can absorb and transport to the host plant. Little is known about the interactions between these two groups in terms of promoting Jerusalem artichoke, Helianthus tuberosus L., which is widely planted by farmers because of its high inulin content. Production depends mainly on synthetic fertilizers as source of plant nutrients. This study aimed to isolate and characterize PSB and investigate the effects of co-inoculation of AMF and PSB on plant performance and inulin accumulation. Isolate UDJA102x89-9, identified as Klebsiella variicola (KV), showed phosphate-solubilizing ability and produced high amounts of several organic acids in vitro and of indole-3-acetic acid (IAA). The experiment combined KV and two AMF species (Glomus multisubtensum (GM) and Rhizophagus intraradices (RI)). Co-inoculation of KV with RI, in combination with rock phosphate, showed the largest increases in plant growth and tuber inulin content, compared both to an unfertilized and fertilized control. This result would reveal whether the phosphate solubilization and IAA property of the PSB in vitro played a significant role in changing plant growth and production, and the available P was subsequently taken up and transported to plant roots by AMF. The high combined effect may have the potential for use by farmers in the future as a biofertilizer for inulin production by Helianthus tuberosus L.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Straub L, Minnameyer A, Strobl V, et al (2020)

From antagonism to synergism: Extreme differences in stressor interactions in one species.

Scientific reports, 10(1):4667.

Interactions between stressors are involved in the decline of wild species and losses of managed ones. Those interactions are often assumed to be synergistic, and per se of the same nature, even though susceptibility can vary within a single species. However, empirical measures of interaction effects across levels of susceptibility remain scarce. Here, we show clear evidence for extreme differences in stressor interactions ranging from antagonism to synergism within honeybees, Apis mellifera. While female honeybee workers exposed to both malnutrition and the pathogen Nosema ceranae showed synergistic interactions and increased stress, male drones showed antagonistic interactions and decreased stress. Most likely sex and division of labour in the social insects underlie these findings. It appears inevitable to empirically test the actual nature of stressor interactions across a range of susceptibility factors within a single species, before drawing general conclusions.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Kulinich A, Wang Q, Duan XC, et al (2020)

Biochemical characterization of the endo-α-N-acetylgalactosaminidase pool of the human gut symbiont Tyzzerella nexilis.

Carbohydrate research, 490:107962.

Three large (2084-, 984-, and 2104-amino acids) endo-α-N-acetylgalactosaminidase candidate genes from the commensal human gut bacterium Tyzzerella nexilis were successfully cloned and subsequently expressed in Escherichia coli. Activity tests of the purified proteins revealed that two of the candidate genes (Tn0153 and Tn2105) were able to hydrolyze the disaccharide unit from Galβ1-3GalNAc-α-pNP. The biochemical characterization revealed optimum pH conditions of 4.0 for both enzymes and temperature optima of 50 °C. The addition of 2-mercaptoethanol, Triton X-100 and urea had only minor effects on the activity of the enzymes, and the addition of imidazole and sodium dodecyl sulfate led to a significant reduction of the enzymes' activities. A mutational study identified and confirmed the role of the catalytically significant amino acids. The present study describes the first functional characterization of members of the GH101 family from this human gut symbiont.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Torres AR, Brito B, Imperial J, et al (2020)

Hydrogen-uptake genes improve symbiotic efficiency in common beans (Phaseolus vulgaris L.).

Antonie van Leeuwenhoek, 113(5):687-696.

Hydrogen-uptake (Hup) activity is implicated in the mitigation of energy losses associated with the biological nitrogen fixation process, and has been related to productivity increases in some legume hosts. However, in common bean (Phaseolus vulgaris L.) the expression of hydrogenase is rare. In this study an 18-kb hup gene cluster from Rhizobium leguminosarum bv. viciae encoding a NiFe hydrogenase was successfully transferred to three common bean rhizobial strains lacking hydrogenase activity (Hup-) but symbiotically very effective and used in commercial inoculants in Brazil: one strain originally from Colombia (Rhizobium tropici CIAT 899), and two strains from Brazil (R. tropici H 12 and Rhizobium freirei PRF 81). The inclusion of NiCl2 in the nutrient solution did not increase hydrogenase activity, indicating that common bean plants allow efficient nickel provision for hydrogenase synthesis in the bacteroids. The symbiotic performance-evaluated by nodulation, plant growth, N accumulation and seed production-of wild-type and Hup+ derivative strains was compared in experiments performed with cultivar Carioca under greenhouse conditions, in sterile substrate and in non-sterile soil. Statistically significant increases in one or more parameters were observed for all three Hup+ derivatives when compared to the respective wild-type strain. Differences were found mainly with the Brazilian strains, reaching impressive increases in nodule efficiency and seed total N content. The results highlight the potential of using Rhizobium Hup+ strains for the design of more energy-efficient inoculants for the common bean crop.

RevDate: 2020-11-23
CmpDate: 2020-11-23

Singh P, Singh RK, Song QQ, et al (2020)

Methods for Estimation of Nitrogen Components in Plants and Microorganisms.

Methods in molecular biology (Clifton, N.J.), 2057:103-112.

Nitrogen (N2) is the most necessary element in the atmosphere, it is an energetic micronutrient for plant growth and development after water, besides its key role in chlorophyll production, which is crucial for photosynthesis process. Biological nitrogen fixation is measured to be the most potent method to deliver a fixed way of nitrogen to the plants. Plant depends on free-living and symbiotic microbes present in the soil for nitrogen because it cannot be absorbed by the plant itself directly from the atmosphere. Many techniques were reported in the laboratory for nitrogen estimation till now, but Kjeldahl digestion and acetylene reduction assay (ARA) techniques became the most popular. In this chapter, we focus on the most common and popular methods used to determine plant N2; awareness obtained through the wide application of these methods should offer the source for the N2 fixation rate in agriculture system.

RevDate: 2020-11-22

Sgibnev AV, EA Kremleva (2020)

Inflammation Mediators Regulate the Microbiota Resistance to Adverse Factors.

Bulletin of experimental biology and medicine pii:10.1007/s10517-020-05002-5 [Epub ahead of print].

We studied the effects of IL-1β, IL-8, TNFα, and prostaglandin E2α in concentrations typically observed in health and during inflammation on the growth of vaginal microbiota and its resistance to factors inhibiting the synthesis of proteins, nucleic acids, and peptidoglycans. An increase in the cytokine levels, characteristic of inflammation, inhibits the growth of Lactobacillus population and improves its resistance to adverse factors. The growth of the population of opportunistic microorganisms (S. aureus, E. coli) is stimulated under these conditions, while their resistance to adverse factors decreases. Hence, it seems that the cytokines regulate the behavior of the host cells and of its bacterial symbionts.

RevDate: 2020-11-21

Nilsson JF, Castellani LG, Draghi WO, et al (2020)

Global transcriptome analysis of Rhizobium favelukesii LPU83 in response to acid stress.

FEMS microbiology ecology pii:5998221 [Epub ahead of print].

Acidic environments naturally occur worldwide and inappropriate agricultural management may also cause acidification of soils. Low soil pH values are an important barrier in the plant-rhizobia interaction. Acidic conditions disturb the establishment of the efficient rhizobia usually used as biofertilizer. This negative effect on the rhizobia-legume symbiosis is mainly due to the low acid-tolerance of the bacteria. Here, we describe the identification of relevant factors in the acid tolerance of Rhizobium favelukesii using transcriptome sequencing. A total of 1,924 genes were differentially expressed under acidic conditions, with ca. 60% underexpressed. R. favelukesii acid response mainly includes changes in the energy metabolism and protein turnover, as well as a combination of mechanisms that may contribute to this phenotype, including GABA and histidine metabolism, cell envelope modifications and reverse proton efflux. We confirmed the acid-sensitive phenotype of a mutant in the braD gene, which showed higher expression under acid stress. Remarkably, 60% of the CDS encoded in the symbiotic plasmid were underexpressed and we evidenced that a strain cured for this plasmid featured an improved performance under acidic conditions. Hence, this work provides relevant information in the characterization of genes associated with tolerance or adaptation to acidic stress of R. favelukesii.

RevDate: 2020-11-21

Song H, Hewitt OH, SM Degnan (2020)

Arginine Biosynthesis by a Bacterial Symbiont Enables Nitric Oxide Production and Facilitates Larval Settlement in the Marine-Sponge Host.

Current biology : CB pii:S0960-9822(20)31594-3 [Epub ahead of print].

Larval settlement and metamorphosis are regulated by nitric oxide (NO) signaling in a wide diversity of marine invertebrates.1-10 It is thus surprising that, in most invertebrates, the substrate for NO synthesis-arginine-cannot be biosynthesized but instead must be exogenously sourced.11 In the sponge Amphimedon queenslandica, vertically inherited proteobacterial symbionts in the larva are able to biosynthesize arginine.12,13 Here, we test the hypothesis that symbionts provide arginine to the sponge host so that nitric oxide synthase expressed in the larva can produce NO, which regulates metamorphosis,8 and the byproduct citrulline (Figure 1). First, we find support for an arginine-citrulline biosynthetic loop in this sponge larval holobiont by using stable isotope tracing. In symbionts, incorporated 13C-citrulline decreases as 13C-arginine increases, consistent with the use of exogenous citrulline for arginine synthesis. In contrast, 13C-citrulline accumulates in larvae as 13C-arginine decreases, demonstrating the uptake of exogenous arginine and its conversion to NO and citrulline. Second, we show that, although Amphimedon larvae can derive arginine directly from seawater, normal settlement and metamorphosis can occur in artificial sea water lacking arginine. Together, these results support holobiont complementation of the arginine-citrulline loop and NO biosynthesis in Amphimedon larvae, suggesting a critical role for bacterial symbionts in the development of this marine sponge. Given that NO regulates settlement and metamorphosis in diverse animal phyla1-10 and arginine is procured externally in most animals,11 we propose that symbionts might play an equally critical regulatory role in this essential life cycle transition in other metazoans.

RevDate: 2020-11-21

Shin J, Marx H, Richards A, et al (2020)

A network-based comparative framework to study conservation and divergence of proteomes in plant phylogenies.

Nucleic acids research pii:5997432 [Epub ahead of print].

Comparative functional genomics offers a powerful approach to study species evolution. To date, the majority of these studies have focused on the transcriptome in mammalian and yeast phylogenies. Here, we present a novel multi-species proteomic dataset and a computational pipeline to systematically compare the protein levels across multiple plant species. Globally we find that protein levels diverge according to phylogenetic distance but is more constrained than the mRNA level. Module-level comparative analysis of groups of proteins shows that proteins that are more highly expressed tend to be more conserved. To interpret the evolutionary patterns of conservation and divergence, we develop a novel network-based integrative analysis pipeline that combines publicly available transcriptomic datasets to define co-expression modules. Our analysis pipeline can be used to relate the changes in protein levels to different species-specific phenotypic traits. We present a case study with the rhizobia-legume symbiosis process that supports the role of autophagy in this symbiotic association.

RevDate: 2020-11-21

Huo H, Wang X, Liu Y, et al (2020)

A Nod factor- and type III secretion system-dependent manner for Robinia pseudoacacia to establish symbiosis with Mesorhizobium amorphae CCNWGS0123.

Tree physiology pii:5995557 [Epub ahead of print].

Under nitrogen-limiting conditions, symbiotic nodulation promotes the growth of legume plants via the fixation of atmospheric nitrogen to ammonia by rhizobia in root nodules. The rhizobial Nod factor (NF) and type III secretion system (T3SS) are two key signaling pathways for establishing the legume-rhizobium symbiosis. However, whether NF signaling is involved in the nodulation of Robinia pseudoacacia and Mesorhizobium amorphae CCNWGS0123, and its symbiotic differences compared to T3SS signaling remain unclear. Therefore, to elucidate the function of NF signaling in nodulation, we mutated nodC in M. amorphae CCNWGS0123, which aborted NF synthesis. Compared to the plants inoculated with the wild type strain, the plants inoculated with the NF-deficient strain exhibited shorter shoots with etiolated leaves. These phenotypic characteristics were similar to those of the plants inoculated with the T3SS-deficient strain, which served as a nod- (non-effective nodulation) control. Both the plants inoculated with the NF- and T3SS-deficient strains formed massive root hair swellings, but no normal infection threads were detected. Sections of the nodules showed that inoculation with the NF- and T3SS-deficient strains induced small, white bumps without any rhizobia inside. Analyzing the accumulation of six plant hormones and the expression of ten plant genes indicated that the NF- and T3SS-deficient strains activated plant defense reactions while suppressing plant symbiotic signaling during the perception and nodulation processes. The requirement for NF signaling appeared to be conserved in two other leguminous trees that can establish symbiosis with M. amorphae CCNWGS0123. In contrast, the function of the T3SS might differ among species, even within the same subfamily (Faboideae). Overall, this work demonstrated that nodulation of R. pseudoacacia and M. amorphae CCNWGS0123 was both NF and T3SS dependent.

RevDate: 2020-11-21

Binet MN, Marchal C, Lipuma J, et al (2020)

Plant health status effects on arbuscular mycorrhizal fungi associated with Lavandula angustifolia and Lavandula intermedia infected by Phytoplasma in France.

Scientific reports, 10(1):20305 pii:10.1038/s41598-020-77240-6.

We investigated root communities of arbuscular mycorrhizal fungi (AMF) in relation to lavender (Lavandula angustifolia) and lavandin (Lavandula intermedia) health status from organic and conventional fields affected by Phytoplasma infection. The intensity of root mycorrhizal colonization was significantly different between diseased and healthy plants and was higher in the latter regardless of agricultural practice. This difference was more pronounced in lavender. The root AMF diversity was influenced by the plant health status solely in lavender and only under the conventional practice resulting in an increase in the AMF abundance and richness. The plant health status did not influence the distribution of root AMF communities in lavandin unlike its strong impact in lavender in both agricultural practices. Finally, among the most abundant molecular operational taxonomic units (MOTUs), four different MOTUs for each plant species were significantly abundant in the roots of healthy lavender and lavandin in either agricultural practice. Our study demonstrated that the plant health status influences root colonization and can influence the diversity and distribution of root AMF communities. Its effects vary according to plant species, can be modified by agricultural practices and allow plants to establish symbiosis with specific AMF species.

RevDate: 2020-11-21

Tavarini S, Clemente C, Bender C, et al (2020)

Health-Promoting Compounds in Stevia: The Effect of Mycorrhizal Symbiosis, Phosphorus Supply and Harvest Time.

Molecules (Basel, Switzerland), 25(22): pii:molecules25225399.

This work aimed to establish the synergic role of arbuscular mycorrhizal fungi (AMF) symbiosis, phosphorus (P) fertilization and harvest time on the contents of stevia secondary metabolites. Consequently, steviol glycosides (SVglys) concentration and profile, total phenols and flavonoids as well as antioxidant assays, have been assessed in inoculated and no-inoculated plants, grown with or without P supply and collected at different growth stages(69, 89 and 123 days after transplanting).The obtained results suggest that the synthesis of stevia secondary metabolites is induced and/or modulated by all the investigated variability factors. In particular, AMF symbiosis promoted total SVglys content and positively influenced the concentration of some minor compounds (steviolbioside, dulcoside A and rebaudioside B), indicating a clear effect of mycorrhizal inoculation on SVglys biosynthetic pathway. Interestingly, only the mycorrhizal plants were able to synthesize rebaudioside B. In addition, P supply provided the highest levels of total phenols and flavonoids at leaf level, together with the maximum in vitro antioxidant activities (FRAP and ORAC). Finally, the harvest time carried out during the full vegetative phase enhanced the entire composition of the phytocomplex (steviolbioside, dulcoside A, stevioside, rebaudioside A, B, C. total phenols and flavonoids). Moreover, polyphenols and SVglys appeared to be the main contributors to the in vitro antioxidant capacity, while only total phenols mostly contributed to the cellular antioxidant activity (CAA). These findings provide original information about the role played by AMF in association with P supply, in modulating the accumulation of bioactive compounds during stevia growth. At the cultivation level, the control of these preharvest factors, together with the most appropriate harvest time, can be used as tools for improving the nutraceutical value of raw material, with particular attention to its exploitation as functional ingredient for food and dietary supplements and cosmetics.

RevDate: 2020-11-21

Sun G, Bai S, Guan Y, et al (2020)

Are fungi-derived genomic regions related to antagonism towards fungi in mosses?.

RevDate: 2020-11-20

Garcia K, Guerrero-Galán C, Frank HER, et al (2020)

Fungal Shaker-like channels beyond cellular K+ homeostasis: A role in ectomycorrhizal symbiosis between Hebeloma cylindrosporum and Pinus pinaster.

PloS one, 15(11):e0242739 pii:PONE-D-20-15111.

Potassium (K+) acquisition, translocation and cellular homeostasis are mediated by various membrane transport systems in all organisms. We identified and described an ion channel in the ectomycorrhizal fungus Hebeloma cylindrosporum (HcSKC) that harbors features of animal voltage-dependent Shaker-like K+ channels, and investigated its role in both free-living hyphae and symbiotic conditions. RNAi lines affected in the expression of HcSKC were produced and used for in vitro mycorrhizal assays with the maritime pine as host plant, under standard or low K+ conditions. The adaptation of H. cylindrosporum to the downregulation of HcSKC was analyzed by qRT-PCR analyses for other K+-related transport proteins: the transporters HcTrk1, HcTrk2, and HcHAK, and the ion channels HcTOK1, HcTOK2.1, and HcTOK2.2. Downregulated HcSKC transformants displayed greater K+ contents at standard K+ only. In such conditions, plants inoculated with these transgenic lines were impaired in K+ nutrition. Taken together, these results support the hypothesis that the reduced expression of HcSKC modifies the pool of fungal K+ available for the plant and/or affects its symbiotic transfer to the roots. Our study reveals that the maintenance of K+ transport in H. cylindrosporum, through the regulation of HcSKC expression, is required for the K+ nutrition of the host plant.

RevDate: 2020-11-20

Qiu X, Macchietto MG, Liu X, et al (2020)

Identification of gut microbiota and microbial metabolites regulated by an antimicrobial peptide lipocalin 2 in high fat diet-induced obesity.

International journal of obesity (2005) pii:10.1038/s41366-020-00712-2 [Epub ahead of print].

Lipocalin 2 (Lcn2), as an antimicrobial peptide is expressed in intestine, and the upregulation of intestinal Lcn2 has been linked to inflammatory bowel disease. However, the role of Lcn2 in shaping gut microbiota during diet-induced obesity (DIO) remains unknown. We found that short-term high fat diet (HFD) feeding strongly stimulates intestinal Lcn2 expression and secretion into the gut lumen. As the HFD feeding prolongs, fecal Lcn2 levels turn to decrease. Lcn2 deficiency accelerates the development of HFD-induced intestinal inflammation and microbiota dysbiosis. Moreover, Lcn2 deficiency leads to the remodeling of microbiota-derived metabolome, including decreased production of short-chain fatty acids (SCFAs) and SCFA-producing microbes. Most importantly, we have identified Lcn2-targeted bacteria and microbiota-derived metabolites that potentially play roles in DIO and metabolic dysregulation. Correlation analyses suggest that Lcn2-targeted Dubosiella and Angelakisella have a novel role in regulating SCFAs production and obesity. Our results provide a novel mechanism involving Lcn2 as an antimicrobial host factor in the control of gut microbiota symbiosis during DIO.

RevDate: 2020-11-20

Durán D, Albareda M, Marina A, et al (2020)

Proteome analysis reveals a significant host-specific response in Rhizobium leguminosarum bv viciae endosymbiotic cells.

Molecular & cellular proteomics : MCP pii:RA120.002276 [Epub ahead of print].

The Rhizobium-legume symbiosis is a beneficial interaction in which the bacterium converts atmospheric nitrogen into ammonia and delivers it to the plant in exchange for carbon compounds. This symbiosis implies the adaptation of bacteria to live inside host plant cells. In this work we apply RP-LC-MS/MS and iTRAQ techniques to study the proteomic profile of endosymbiotic cells (bacteroids) induced by Rhizobium leguminosarum bv viciae strain UPM791 in legume nodules. Nitrogenase subunits, tricarboxylic acid cycle enzymes, and stress response proteins are amongst the most abundant from over one thousand rhizobial proteins identified in pea (Pisum sativum) bacteroids. Comparative analysis of bacteroids induced in pea and in lentil (Lens culinaris)nodules revealed the existence of a significant host-specific differential response affecting dozens of bacterial proteins, including stress-related proteins, transcriptional regulators, and proteins involved in the carbon and nitrogen metabolisms. A mutant affected in one of these proteins, homologous to a GntR-like transcriptional regulator, showed a symbiotic performance significantly impaired in symbiosis with pea, but not with lentil plants. Analysis of the proteomes of bacteroids isolated from both hosts also revealed the presence of different sets of plant-derived nodule-specific cysteine rich (NCR) peptides, indicating that the endosymbiotic bacteria find a host-specific cocktail of chemical stressors inside the nodule. By studying variations of the bacterial response to different plant cell environments we will be able to identify specific limitations imposed by the host that might give us clues for the improvement of rhizobial performance.

RevDate: 2020-11-20
CmpDate: 2020-11-20

Coates LC, Mahoney J, Ramsey JS, et al (2020)

Development on Citrus medica infected with 'Candidatus Liberibacter asiaticus' has sex-specific and -nonspecific impacts on adult Diaphorina citri and its endosymbionts.

PloS one, 15(10):e0239771.

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.

RevDate: 2020-11-20
CmpDate: 2020-11-20

García-Del Portillo F (2020)

Building peptidoglycan inside eukaryotic cells: A view from symbiotic and pathogenic bacteria.

Molecular microbiology, 113(3):613-626.

The peptidoglycan (PG), as the exoskeleton of most prokaryotes, maintains a defined shape and ensures cell integrity against the high internal turgor pressure. These important roles have attracted researchers to target PG metabolism in order to control bacterial infections. Most studies, however, have been performed in bacteria grown under laboratory conditions, leading to only a partial view on how the PG is synthetized in natural environments. As a case in point, PG metabolism and its regulation remain poorly understood in symbiotic and pathogenic bacteria living inside eukaryotic cells. This review focuses on the PG metabolism of intracellular bacteria, emphasizing the necessity of more in vivo studies involving the analysis of enzymes produced in the intracellular niche and the isolation of PG from bacteria residing within eukaryotic cells. The review also points to persistent infections caused by some intracellular bacterial pathogens and the extent at which the PG could contribute to establish such physiological state. Based on recent evidences, I speculate on the idea that certain structural features of the PG may facilitate attenuation of intracellular growth. Lastly, I discuss recent findings in endosymbionts supporting a cooperation between host and bacterial enzymes to assemble a mature PG.

RevDate: 2020-11-20
CmpDate: 2020-11-20

Asfaw B, Aserse AA, Asefa F, et al (2020)

Genetically diverse lentil- and faba bean-nodulating rhizobia are present in soils across Central and Southern Ethiopia.

FEMS microbiology ecology, 96(3):.

In total 196 bacterial isolates were obtained from root nodules of lentil (Lens culinaris) and faba bean (Vicia faba) grown on soil samples collected from 10 different sites in central and southern parts of Ethiopia. All isolates were identified as members of the genus Rhizobium by using recA gene sequence analysis. In the recA phylogenetic tree 195 rhizobial strains were classified into nine genospecies. The phylogeny of symbiotic genes nodC and nifH revealed five and six distinct groups respectively, largely dominated by symbiovar viciae. A multivariate analysis showed that environmental variables of the sampling sites considered in this study had more effect on the distribution and composition of the genospecies than the host legumes of the strains. Twenty representative strains, selected based on their isolation site, host plant and nodC group, were able to nodulate all lentil, faba bean, field pea (Pisum abyssinicum) and grass pea (Lathyrus sativus) plants in a greenhouse test in axenic conditions. The majority of the rhizobial strains were effective nitrogen-fixing symbionts for all tested legumes, indicating their potential to serve as broad host-range inoculants in agriculture. The present work suggests the presence of taxonomically and symbiotically diverse rhizobial species for legumes in the Viciae tribe in Ethiopia.

RevDate: 2020-11-20
CmpDate: 2020-11-20

Javadzadeh SG, A Asoodeh (2020)

A novel textile dye degrading extracellular laccase from symbiotic bacterium of Bacillus sp. CF96 isolated from gut termite (Anacanthotermes).

International journal of biological macromolecules, 145:355-363.

Oxidation of phenolic compounds is an urgent need in textile industry, biological refinements, pulp and paper production. In present study, a laccase was purified from symbiotic bacterium of Bacillus sp. CF96 existing in termite digestive system. The extracellular laccase was purified via amnion sulfate precipitation, membrane dialysis, and ion exchange chromatography. The results showed that the Bacillus CF96 laccase possesses a molecular mass of 63 kDa, an optimal pH and temperature of 8.0 and 60 °C. Results showed that Zn2+, Mn2+ and Fe2+ were considered as the activator ions, while SDS was the main inhibitor. Using syringaldazine (SGZ) as substrate, the half-life of laccase at optimal temperature was 148 min; Km and Vmax were 0.737 μM and 100.5 U/mg. In addition, the enzyme showed a high effect on indigo dye with 90% bleaching capacity compared to control. In conclusion, the laccase has potential applications in industries under the provided optimal conditions.

RevDate: 2020-11-19

Ramírez-Flores MR, Perez-Limon S, Li M, et al (2020)

The genetic architecture of host response reveals the importance of arbuscular mycorrhizae to maize cultivation.

eLife, 9: pii:61701.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in cultivated soils, forming symbiotic relationships with the roots of major crop species. Studies in controlled conditions have demonstrated the potential of AMF to enhance the growth of host plants. However, it is difficult to estimate the actual benefit in the field, not least because of the lack of suitable AMF-free controls. Here we implement a novel strategy using the selective incorporation of AMF-resistance into a genetic mapping population to evaluate maize response to AMF. We found AMF to account for about one-third of the grain production in a medium input field, as well as to affect the relative performance of different plant genotypes. Characterization of the genetic architecture of the host response indicated a trade-off between mycorrhizal dependence and benefit. We identified several QTL linked to host benefit, supporting the feasibility of breeding crops to maximize profit from symbiosis with AMF.

RevDate: 2020-11-19

Abdulsalam O, Wagner K, Wirth S, et al (2020)

Phytohormones and volatile organic compounds, like geosmin, in the ectomycorrhiza of Tricholoma vaccinum and Norway spruce (Picea abies).

Mycorrhiza pii:10.1007/s00572-020-01005-2 [Epub ahead of print].

The ectomycorrhizospheric habitat contains a diverse pool of organisms, including the host plant, mycorrhizal fungi, and other rhizospheric microorganisms. Different signaling molecules may influence the ectomycorrhizal symbiosis. Here, we investigated the potential of the basidiomycete Tricholoma vaccinum to produce communication molecules for the interaction with its coniferous host, Norway spruce (Picea abies). We focused on the production of volatile organic compounds and phytohormones in axenic T. vaccinum cultures, identified the potential biosynthesis genes, and investigated their expression by RNA-Seq analyses. T. vaccinum released volatiles not usually associated with fungi, like limonene and β-barbatene, and geosmin. Using stable isotope labeling, the biosynthesis of geosmin was elucidated. The geosmin biosynthesis gene ges1 of T. vaccinum was identified, and up-regulation was scored during mycorrhiza, while a different regulation was seen with mycorrhizosphere bacteria. The fungus also released the volatile phytohormone ethylene and excreted salicylic and abscisic acid as well as jasmonates into the medium. The tree excreted the auxin, indole-3-acetic acid, and its biosynthesis intermediate, indole-3-acetamide, as well as salicylic acid with its root exudates. These compounds could be shown for the first time in exudates as well as in soil of a natural ectomycorrhizospheric habitat. The effects of phytohormones present in the mycorrhizosphere on hyphal branching of T. vaccinum were assessed. Salicylic and abscisic acid changed hyphal branching in a concentration-dependent manner. Since extensive branching is important for mycorrhiza establishment, a well-balanced level of mycorrhizospheric phytohormones is necessary. The regulation thus can be expected to contribute to an interkingdom language.

RevDate: 2020-11-19

Shigli K, Nayak SS, Menon K, et al (2020)

Dietary counseling: A requisite in geriatric prosthodontics.

Journal of family medicine and primary care, 9(9):5081-5082 pii:JFMPC-9-5081.

RevDate: 2020-11-19

Melo Clavijo J, Frankenbach S, Fidalgo C, et al (2020)

Identification of scavenger receptors and thrombospondin-type-1 repeat proteins potentially relevant for plastid recognition in Sacoglossa.

Ecology and evolution, 10(21):12348-12363 pii:ECE36865.

Functional kleptoplasty is a photosymbiotic relationship, in which photosynthetically active chloroplasts serve as an intracellular symbiont for a heterotrophic host. Among Metazoa, functional kleptoplasty is only found in marine sea slugs belonging to the Sacoglossa and recently described in Rhabdocoela worms. Although functional kleptoplasty has been intensively studied in Sacoglossa, the fundamentals of the specific recognition of the chloroplasts and their subsequent incorporation are unknown. The key to ensure the initiation of any symbiosis is the ability to specifically recognize the symbiont and to differentiate a symbiont from a pathogen. For instance, in photosymbiotic cnidarians, several studies have shown that the host innate immune system, in particular scavenger receptors (SRs) and thrombospondin-type-1 repeat (TSR) protein superfamily, is playing a major role in the process of recognizing and differentiating symbionts from pathogens. In the present study, SRs and TSRs of three Sacoglossa sea slugs, Elysia cornigera, Elysia timida, and Elysia chlorotica, were identified by translating available transcriptomes into potential proteins and searching for receptor specific protein and/or transmembrane domains. Both receptors classes are highly diverse in the slugs, and many new domain arrangements for each receptor class were found. The analyses of the gene expression of these three species provided a set of species-specific candidate genes, that is, SR-Bs, SR-Es, C-type lectins, and TSRs, that are potentially relevant for the recognition of kleptoplasts. The results set the base for future experimental studies to understand if and how these candidate receptors are indeed involved in chloroplast recognition.

RevDate: 2020-11-19

Wilkes TI, Warner DJ, Edmonds-Brown V, et al (2020)

Species-Specific Interactions of Bacillus Innocula and Arbuscular Mycorrhizal Fungi Symbiosis with Winter Wheat.

Microorganisms, 8(11): pii:microorganisms8111795.

Arbuscular mycorrhizal (AM) fungi establish close interactions with host plants, an estimated 80% of vascular plant species. The host plant receives additional soil bound nutrients that would otherwise not be available. Other components of the microbiome, such as rhizobacteria, may influence interactions between AM fungi and the host plant. Within a commercial arable crop selected rhizobacteria in combination with AM fungi may benefit crop yields. The precise nature of interactions between rhizobacteria and AM fungi in a symbiotic relationship overall requires greater understanding. The present study aims to assess this relationship by quantifying: (1) AM fungal intracellular root structures (arbuscules) and soil glomalin as an indicator of AM fungal growth; and (2) root length and tiller number as a measure of crop growth, in response to inoculation with one of three species of Bacillus: B. amyloliquefaciences, B. pumilis, or B. subtilis. The influence of soil management, conventional (CT) or zero tillage (ZT) was a further variable evaluated. A significant (p < 0.0001) species-specific impact on the number of quantifiable AM fungal arbuscules was observed. The inoculation of winter wheat (Triticum aestivum) with B. amyloliquefaciences had a positive impact on AM fungal symbiosis, as indicated by an average of 3226 arbuscules per centimetre of root tissue. Bacillus subtilis increased root length significantly (p < 0.01) but decreased fungal symbiosis (p < 0.01). The inoculation of field soils altered the concentration of glomalin, an indicator of AM fungal growth, significantly (p < 0.00001) for each tillage treatment. The greatest increase was associated with B. amyloliquefaciences for both CT (p < 0.0001) and ZT (p < 0.00001). Bacillus subtilis reduced measured glomalin significantly in both tillage treatments (p < 0.0001 and p < 0.00001 for CT and ZT respectively). The interaction between rhizobacteria and AM fungi is variable, being beneficial or detrimental depending on species. This relationship was evident in both tillage treatments and has important implications for maximizing symbiosis in the crop plant-microbiome present in agricultural systems.

RevDate: 2020-11-18

Kumar PR, Moore JA, Bowles KM, et al (2020)

Mitochondrial oxidative phosphorylation in cutaneous melanoma.

British journal of cancer pii:10.1038/s41416-020-01159-y [Epub ahead of print].

The Warburg effect in tumour cells is associated with the upregulation of glycolysis to generate ATP, even under normoxic conditions and the presence of fully functioning mitochondria. However, scientific advances made over the past 15 years have reformed this perspective, demonstrating the importance of oxidative phosphorylation (OXPHOS) as well as glycolysis in malignant cells. The metabolic phenotypes in melanoma display heterogeneic dynamism (metabolic plasticity) between glycolysis and OXPHOS, conferring a survival advantage to adapt to harsh conditions and pathways of chemoresistance. Furthermore, the simultaneous upregulation of both OXPHOS and glycolysis (metabolic symbiosis) has been shown to be vital for melanoma progression. The tumour microenvironment (TME) has an essential supporting role in promoting progression, invasion and metastasis of melanoma. Mesenchymal stromal cells (MSCs) in the TME show a symbiotic relationship with melanoma, protecting tumour cells from apoptosis and conferring chemoresistance. With the significant role of OXPHOS in metabolic plasticity and symbiosis, our review outlines how mitochondrial transfer from MSCs to melanoma tumour cells plays a key role in melanoma progression and is the mechanism by which melanoma cells regain OXPHOS capacity even in the presence of mitochondrial mutations. The studies outlined in this review indicate that targeting mitochondrial trafficking is a potential novel therapeutic approach for this highly refractory disease.

RevDate: 2020-11-18

Zhou F, Xu L, Wu X, et al (2020)

Symbiotic Bacterium-Derived Organic Acids Protect Delia antiqua Larvae from Entomopathogenic Fungal Infection.

mSystems, 5(6):.

Colonization resistance, i.e., the protective effects of associated microbiota for the animal host against pathogen infection, has been studied widely over the last 100 years. However, few molecules mediating colonization resistance have been identified. In the symbiosis formed by Delia antiqua and its associated microbes, six bacteria protect larvae from infection with the entomopathogen Beauveria bassiana, providing an ideal model to investigate the chemical mechanism for colonization resistance. Subsequently using this symbiotic system, we first compared effects of the six bacterial species, and one control bacterium (Klebsiella oxytoca) that showed no antifungal effects, on B. bassiana and its infection of D. antiqua Second, metabolomic profiles of the six bacteria and K. oxytoca were compared to identify candidate metabolites that may prevent infection. Third, the concentrations of candidate metabolites in situ from axenic and nonaxenic larvae were determined. Finally, effects of artificial metabolite cocktails on B.bassiana and its infection of D. antiqua larvae were determined. Results showed that compared to K. oxytoca, the six bacteria produced a metabolite cocktail showing inhibitory effects on conidial germination, mycelial growth of B.bassiana, and fungal infection. Our work revealed novel molecules that mediate colonization resistance, which could help in developing chemical mechanisms of colonization resistance. Moreover, this work may aid in discovery and expansion of new bioactive antibiotics, promoting development of prophylactic and therapeutic approaches for treating infectious diseases.IMPORTANCE The protection of associated microbiota for their animal hosts against pathogen infection has been studied widely over the last 100 years. However, how those microbes protect the animal host remains unclear. In former studies, body surface microbes of one insect, Delia antiqua, protected the insect larvae from infection with the entomopathogen Beauveria bassiana By comparing the metabolites produced by microbes that protect the insect and microbes that cannot protect the insect, the question of how the microbes protect the insect is answered. It turns out that body surface bacteria produce a metabolite cocktail that inhibits colonization of B.bassiana and consequently protects the insect. This work reveals novel molecules with antifungal activity, which may aid in discovery and expansion of new prophylactic and therapeutic natural chemicals for treating infectious diseases.

RevDate: 2020-11-19
CmpDate: 2020-11-19

Zhu X, Mao Y, Guo M, et al (2020)

Enhancement of anti-acne effect of Scutellaria baicalensis extract by fermentation with symbiotic fungus Penicillium decumbens.

Journal of bioscience and bioengineering, 130(5):457-463.

Inflammatory responses stimulated by Propionibacterium acnes have been shown to be major etiological factors in the pathogenesis of acne. Scutellaria baicalensis, a popular traditional Chinese medicine, has been widely shown to have anti-inflammatory effects. In this study, primary component analysis and primary effective component analysis were conducted. The results showed that wogonin (1.15 mg/g S. baicalensis extract) possessed better anti-acne effects than wogonoside (8.71 mg/g S. baicalensis extract) in inhibiting the up-regulation of IL-1β and IL-8 level caused by P. acnes via inactivation of the MAPK and NF-κB signaling pathways. To enhance the anti-acne effects of S. baicalensis extract, an environmentally friendly and healthy plant fermentation strategy was used to efficiently convert glycoside-type constituents into bioactive aglycone. S. baicalensis extract was fermented by symbiotic fungus Penicillium decumbens f3-1 to transform wogonoside into wogonin with a conversion rate of 91.0% after 4 days. Fermented S. baicalensis extract (FSE) showed higher potential anti-acne effects than non-fermented S. baicalensis extract (NSE) by inhibiting the up-regulation of IL-1β and IL-8. Thus, P. decumbens-fermented S. baicalensis Extract may be used for developing new anti-acne cosmetic ingredients.

RevDate: 2020-11-18
CmpDate: 2020-11-18

Koto A, Nobu MK, R Miyazaki (2020)

Deep Sequencing Uncovers Caste-Associated Diversity of Symbionts in the Social Ant Camponotus japonicus.

mBio, 11(2):.

Symbiotic microorganisms can have a profound impact on the host physiology and behavior, and novel relationships between symbionts and their hosts are continually discovered. A colony of social ants consists of various castes that exhibit distinct lifestyles and is, thus, a unique model for investigating how symbionts may be involved in host eusociality. Yet our knowledge of social ant-symbiont dynamics has remained rudimentary. Through 16S rRNA gene deep sequencing of the carpenter ant Camponotus japonicus symbiont community across various castes, we here report caste-dependent diversity of commensal gut microbiota and lineage divergence of "Candidatus Blochmannia," an obligate endosymbiont. While most prevalent gut-associated bacterial populations are found across all castes (Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and Cyanobacteria), we also discovered uncultured populations that are found only in males (belonging to Corynebacteriales, Alkanindiges, and Burkholderia). Most of those populations are not detected in laboratory-maintained queens and workers, suggesting that they are facultative gut symbionts introduced via environmental acquisition. Further inspection of "Ca. Blochmannia" endosymbionts reveals that two populations are dominant in all individuals across all castes but that males preferentially contain two different sublineages that are diversified from others. Clearly, each caste has distinct symbiont communities, suggesting an overlooked biological aspect of host-symbiont interaction in social insects.IMPORTANCE Social animals, such as primates and some insects, have been shown to exchange symbiotic microbes among individuals through sharing diet or habitats, resulting in increased consistency of microbiota among social partners. The ant is a representative of social insects exhibiting various castes within a colony; queens, males, and nonreproductive females (so-called workers) show distinct morphologies, physiologies, and behaviors but tightly interact with each other in the nest. However, how this social context affects their gut microbiota has remained unclear. In this study, we deeply sequenced the gut symbiont community across various castes of the carpenter ant Camponotus japonicus We report caste-dependent diversity of commensal gut microbial community and lineage divergence of the mutualistic endosymbiont "Candidatus Blochmannia." This report sheds light on the hidden diversity in microbial populations and community structure associated with guts of males in social ants.

RevDate: 2020-11-19
CmpDate: 2020-11-19

Reyes-Prieto M, Vargas-Chávez C, Llabrés M, et al (2020)

An update on the Symbiotic Genomes Database (SymGenDB): a collection of metadata, genomic, genetic and protein sequences, orthologs and metabolic networks of symbiotic organisms.

Database : the journal of biological databases and curation, 2020:.

The Symbiotic Genomes Database (SymGenDB; http://symbiogenomesdb.uv.es/) is a public resource of manually curated associations between organisms involved in symbiotic relationships, maintaining a catalog of completely sequenced/finished bacterial genomes exclusively. It originally consisted of three modules where users could search for the bacteria involved in a specific symbiotic relationship, their genomes and their genes (including their orthologs). In this update, we present an additional module that includes a representation of the metabolic network of each organism included in the database, as Directed Acyclic Graphs (MetaDAGs). This module provides unique opportunities to explore the metabolism of each individual organism and/or to evaluate the shared and joint metabolic capabilities of the organisms of the same genera included in our listing, allowing users to construct predictive analyses of metabolic associations and complementation between systems. We also report a ~25% increase in manually curated content in the database, i.e. bacterial genomes and their associations, with a final count of 2328 bacterial genomes associated to 498 hosts. We describe new querying possibilities for all the modules, as well as new display features for the MetaDAGs module, providing a relevant range of content and utility. This update continues to improve SymGenDB and can help elucidate the mechanisms by which organisms depend on each other.

RevDate: 2020-11-19
CmpDate: 2020-11-19

Wang HL, Lei T, Wang XW, et al (2020)

A newly recorded Rickettsia of the Torix group is a recent intruder and an endosymbiont in the whitefly Bemisia tabaci.

Environmental microbiology, 22(4):1207-1221.

The bacterium Rickettsia is found widely in phytophagous insects and often exerts profound effects on the phenotype and fitness of its hosts. Here, we decrypt a new, independent, phylogenetically ancient Torix Rickettsia endosymbiont found constantly in a laboratory line of an economically important insect Asia II 7, a putative species of the Bemisia tabaci whitefly complex (Hemiptera: Aleyrodidae), and occasionally in field whitefly populations. This new Rickettsia distributes throughout the body of its whitefly host. Genetically, compared to Rickettsia_bellii_MEAM1 found earlier in whiteflies, the new Rickettsia species has more gene families and pathways, which may be important factors in shaping specific symbiotic relationships. We propose the name 'Candidatus Rickettsia_Torix_Bemisia_tabaci (RiTBt)' for this new endosymbiont associated with whiteflies. Comparative genomic analyses indicate that RiTBi may be a relatively recent intruder in whiteflies given its low abundance in the field and relatively larger genome compared to Rickettsia_bellii_MEAM1.

RevDate: 2020-11-18
CmpDate: 2020-11-18

Pupier CA, Fine M, Bednarz VN, et al (2019)

Productivity and carbon fluxes depend on species and symbiont density in soft coral symbioses.

Scientific reports, 9(1):17819.

Soft corals often constitute one of the major benthic groups of coral reefs. Although they have been documented to outcompete reef-building corals following environmental disturbances, their physiological performance and thus their functional importance in reefs are still poorly understood. In particular, the acclimatization to depth of soft corals harboring dinoflagellate symbionts and the metabolic interactions between these two partners have received little attention. We performed stable isotope tracer experiments on two soft coral species (Litophyton sp. and Rhytisma fulvum fulvum) from shallow and upper mesophotic Red Sea coral reefs to quantify the acquisition and allocation of autotrophic carbon within the symbiotic association. Carbon acquisition and respiration measurements distinguish Litophyton sp. as mainly autotrophic and Rhytisma fulvum fulvum as rather heterotrophic species. In both species, carbon acquisition was constant at the two investigated depths. This is a major difference from scleractinian corals, whose carbon acquisition decreases with depth. In addition, carbon acquisition and photosynthate translocation to the host decreased with an increase in symbiont density, suggesting that nutrient provision to octocoral symbionts can quickly become a limiting factor of their productivity. These findings improve our understanding of the biology of soft corals at the organism-scale and further highlight the need to investigate how their nutrition will be affected under changing environmental conditions.

RevDate: 2020-11-18
CmpDate: 2020-11-18

Forrester GE, Chille E, Nickles K, et al (2019)

Behavioural mechanisms underlying parasite-mediated competition for refuges in a coral reef fish.

Scientific reports, 9(1):15487 pii:10.1038/s41598-019-52005-y.

Parasites have been increasingly recognized as participants in indirect ecological interactions, including those mediated by parasite-induced changes to host behaviour (trait-mediated indirect interactions or TMIIs). In most documented examples, host behaviours altered by parasites increase susceptibility to predation because the predator is also a host (host-manipulation). Here, we test for a TMII in which a parasitic copepod modifies the predator-prey interaction between a small goby host and several larger predatory fish. Gobies compete for crevices in the reef to avoid predation and goby mortality increases more rapidly with increasing refuge shortage for parasitized gobies than for those free of parasites. We found interactive effects of refuge shortage and parasitism on two behaviours we predicted might be associated with parasite-mediated competition for refuges. First, as refuge-shortage increases, the rate of aggression among gobies increases and parasitism intensifies this interaction. Second, goby proximity to refuges increases as refuges become scarce, but parasitism nullifies this increase. In combination, these parasite-induced changes in behaviour may explain why parasitized gobies are poor competitors for refuges. Because the parasite is not trophically transmitted via host manipulation, these altered behaviours in parasitized gobies are likely coincidental to infection.

RevDate: 2020-11-18
CmpDate: 2020-11-18

Monin L, Whettlock EM, V Male (2020)

Immune responses in the human female reproductive tract.

Immunology, 160(2):106-115.

Mucosal surfaces are key interfaces between the host and its environment, but also constitute ports of entry for numerous pathogens. The gut and lung mucosae act as points of nutrient and gas exchange, respectively, but the physiological purpose of the female reproductive tract (FRT) is to allow implantation and development of the fetus. Our understanding of immune responses in the FRT has traditionally lagged behind our grasp of the situation at other mucosal sites, but recently reproductive immunologists have begun to make rapid progress in this challenging area. Here, we review current knowledge of immune responses in the human FRT and their heterogeneity within and between compartments. In the commensal-rich vagina, the immune system must allow the growth of beneficial microbes, whereas the key challenge in the uterus is allowing the growth of the semi-allogeneic fetus. In both compartments, these objectives must be balanced with the need to eliminate pathogens. Our developing understanding of immune responses in the FRT will help us develop interventions to prevent the spread of sexually transmitted diseases and to improve outcomes of pregnancy for mothers and babies.

RevDate: 2020-11-13
CmpDate: 2020-11-13

Stoian V, Vidican R, Crişan I, et al (2019)

Sensitive approach and future perspectives in microscopic patterns of mycorrhizal roots.

Scientific reports, 9(1):10233 pii:10.1038/s41598-019-46743-2.

The harmonization of methodologies for the assessment of radicular endophytic colonization is a current necessity, especially for the arbuscular mycorrhizas. The functionality of mycorrhizal symbionts for plants can be described only by indicators obtained based on microscopic analysis. That is the reason for which a unifying methodology will lead to the achievement of highly correlated indicators comparable from one research to another. Our proposed methodology can further digitize the microscopic observations of colonization. The MycoPatt system is developed as a methodological framework for obtaining objective and comparable microscopic observations. The horizontal, vertical and transversal indicators are highly adaptable and allow the tracking of mycorrhizal colonization in root length. All structures developed by symbionts can be traced and the obtained metadata can be compared without any transformation. Mycorrhizal maps have a high degree of applicability in evaluating soil inoculum efficiency. In the future, the application of this method will lead to digital maps with a high degree of accuracy. MycoPatt allows the mathematical expression of colonization patterns, being a complex model that converts biological data into statistically comparable indicators. This will further allow obtaining inferences with applicative importance and similarity spectra for the colonizing fungi and host plants.

RevDate: 2020-11-17

Ci D, Tang Z, Ding H, et al (2020)

The synergy effect of arbuscular mycorrhizal fungi symbiosis and exogenous calcium on bacterial community composition and growth performance of peanut (Arachis hypogaea L.) in saline alkali soil.

Journal of microbiology (Seoul, Korea) pii:10.1007/s12275-021-0317-3 [Epub ahead of print].

Peanut (Arachis hypogaea. L) is an important oil seed crop. Both arbuscular mycorrhizal fungi (AMF) symbiosis and calcium (Ca2+) application can ameliorate the impact of saline soil on peanut production, and the rhizosphere bacterial communities are also closely correlated with peanut salt tolerance; however, whether AMF and Ca2+ can withstand high-salinity through or partially through modulating rhizosphere bacterial communities is unclear. Here, we used the rhizosphere bacterial DNA from saline alkali soil treated with AMF and Ca2+ alone or together to perform high-throughput sequencing of 16S rRNA genes. Taxonomic analysis revealed that AMF and Ca2+ treatment increased the abundance of Proteobacteria and Firmicutes at the phylum level. The nitrogen-fixing bacterium Sphingomonas was the dominant genus in these soils at the genus level, and the soil invertase and urease activities were also increased after AMF and Ca2+ treatment, implying that AMF and Ca2+ effectively improved the living environment of plants under salt stress. Moreover, AMF combined with Ca2+ was better than AMF or Ca2+ alone at altering the bacterial structure and improving peanut growth in saline alkali soil. Together, AMF and Ca2+ applications are conducive to peanut salt adaption by regulating the bacterial community in saline alkali soil.

RevDate: 2020-11-17

Paparokidou C, Leake JR, Beerling DJ, et al (2020)

Phosphate availability and ectomycorrhizal symbiosis with Pinus sylvestris have independent effects on the Paxillus involutus transcriptome.

Mycorrhiza pii:10.1007/s00572-020-01001-6 [Epub ahead of print].

Many plant species form symbioses with ectomycorrhizal fungi, which help them forage for limiting nutrients in the soil such as inorganic phosphate (Pi). The transcriptional responses to symbiosis and nutrient-limiting conditions in ectomycorrhizal fungal hyphae, however, are largely unknown. An artificial system was developed to study ectomycorrhizal basidiomycete Paxillus involutus growth in symbiosis with its host tree Pinus sylvestris at different Pi concentrations. RNA-seq analysis was performed on P. involutus hyphae growing under Pi-limiting conditions, either in symbiosis or alone. We show that Pi starvation and ectomycorrhizal symbiosis have an independent effect on the P. involutus transcriptome. Notably, low Pi availability induces expression of newly identified putative high-affinity Pi transporter genes, while reducing the expression of putative organic acid transporters. Additionally, low Pi availability induces a close transcriptional interplay between P and N metabolism. GTP-related signalling was found to have a positive effect in the maintenance of ectomycorrhizal symbiosis, whereas multiple putative cytochrome P450 genes were found to be downregulated, unlike arbuscular mycorrhizal fungi. We provide the first evidence of global transcriptional changes induced by low Pi availability and ectomycorrhizal symbiosis in the hyphae of P. involutus, revealing both similarities and differences with better-characterized arbuscular mycorrhizal fungi.

RevDate: 2020-11-17

de Oliveira IF, Simeone MLF, de Guimarães CC, et al (2020)

Sorgoleone concentration influences mycorrhizal colonization in sorghum.

Mycorrhiza pii:10.1007/s00572-020-01006-1 [Epub ahead of print].

The association between arbuscular mycorrhizal fungi (AMF) and sorghum, the fifth most cultivated cereal in the world and a staple food for many countries, is relevant to improving phosphorus (P) absorption. The importance of root exudation as a signal for the symbiosis has been shown for several species, but a complete understanding of the signaling molecules involved in the mycorrhizal symbiosis signaling pathway has not yet been elucidated. In this context, we investigated the effect of sorgoleone, one of the most studied allelochemicals and a predominant compound of root exudates in sorghum, on AMF colonization and consequently P uptake and plant growth on a sorghum genotype. The sorghum genotype P9401 presents low endogenous sorgoleone content, and when it was inoculated with Rhizophagus clarus together with 5 and 10 µM sorgoleone, mycorrhizal colonization was enhanced. A significant enhancement of mycorrhizal colonization and an increase of P content and biomass were observed when R. clarus was inoculated together with 20 µM sorgoleone. Thus, our results indicate that sorgoleone influences mycorrhizal colonization, but the mechanisms by which it does so still need to be revealed.

RevDate: 2020-11-16

de Souza Campos PM, Borie F, Cornejo P, et al (2020)

Wheat root trait plasticity, nutrient acquisition and growth responses are dependent on specific arbuscular mycorrhizal fungus and plant genotype interactions.

Journal of plant physiology, 256:153297 pii:S0176-1617(20)30187-5 [Epub ahead of print].

This study aimed to examine how interactions at both plant genotype and arbuscular mycorrhizal fungus species levels affected the expression of root traits and the subsequent effect on plant nutrition and growth. We used two wheat cultivars with contrasting phosphorus (P) acquisition efficiencies (Tukan and Crac) and two arbuscular mycorrhizal (AM) fungi (Rhizophagus intraradices and Claroideoglomus claroideum). Plant growth, as well as morphological and architectural root traits, were highly dependent on the myco-symbiotic partner in the case of the less P-acquisition efficient cultivar Tukan, with mycorrhizal responses ranging from -45 to 54 % with respect to non-mycorrhizal plants. Meanwhile, these responses were between only -7 and 5 % in the P-acquisition efficient cultivar Crac. The AM fungal species produced contrasting mechanisms in the improvement of plant nutrition and root trait responses. Colonization by R. intraradices increased Ca accumulation, regardless of the cultivar, but reduced root growth on Tukan plants. On the other hand, C. claroideum increased P content in both cultivars, with a concomitant increase in root growth and diffusion-based nutrient acquisition by Tukan. Moreover, plants in symbiosis with R. intraradices showed greater organic acid concentration in their rhizosphere compared to C. claroideum-colonized plants, especially Tukan (24 and 35 % more citrate and oxalate, respectively). Our results suggest that the responses in plant-AM fungal interactions related to nutrient dynamics are highly influenced at the fungus level and also by intra-specific variations in root traits at the genotype level, while growth responses related to improved nutrition depend on plant intrinsic acquisition efficiency.

RevDate: 2020-11-17
CmpDate: 2020-11-17

Matsuda Y, Yamaguchi Y, Matsuo N, et al (2020)

Communities of mycorrhizal fungi in different trophic types of Asiatic Pyrola japonica sensu lato (Ericaceae).

Journal of plant research, 133(6):841-853.

Mixotrophic plants obtain carbon by their own photosynthetic activity and from their root-associated mycorrhizal fungi. Mixotrophy is deemed a pre-adaptation for evolution of mycoheterotrophic nutrition, where plants fully depend on fungi and lose their photosynthetic activity. The aim of this study was to clarify mycorrhizal dependency and heterotrophy level in various phenotypes of mixotrophic Pyrola japonica (Ericaceae), encompassing green individuals, rare achlorophyllous variants (albinos) and a form with minute leaves, P. japonica f. subaphylla. These three phenotypes were collected in two Japanese forests. Phylogenetic analysis of both plants and mycorrhizal fungi was conducted based on DNA barcoding. Enrichment in 13C among organs (leaves, stems and roots) of the phenotypes with reference plants and fungal fruitbodies were compared by measuring stable carbon isotopic ratio. All plants were placed in the same clade, with f. subaphylla as a separate subclade. Leaf 13C abundances of albinos were congruent with a fully mycoheterotrophic nutrition, suggesting that green P. japonica leaves are 36.8% heterotrophic, while rhizomes are 74.0% heterotrophic. There were no significant differences in δ13C values among organs in both albino P. japonica and P. japonica f. subaphylla, suggesting full and high mycoheterotrophic nutrition, respectively. Among 55 molecular operational taxonomic units (OTUs) detected as symbionts, the genus Russula was the most abundant in each phenotype and its dominance was significantly higher in albino P. japonica and P. japonica f. subaphylla. Russula spp. detected in P. japonica f. subaphylla showed higher dissimilarity with other phenotypes. These results suggest that P. japonica sensu lato is prone to evolve mycoheterotrophic variants, in a process that changes its mycorrhizal preferences, especially towards the genus Russula for which this species has a marked preference.

RevDate: 2020-11-16
CmpDate: 2020-11-16

Geetha Thanuja K, Annadurai B, Thankappan S, et al (2020)

Non-rhizobial endophytic (NRE) yeasts assist nodulation of Rhizobium in root nodules of blackgram (Vigna mungo L.).

Archives of microbiology, 202(10):2739-2749.

The signal orchestration between legumes and the rhizobia attribute to symbiotic nitrogen fixation through nodule formation. Root nodules serve as a nutrient-rich reservoir and harbor diverse microbial communities. However, the existence of non-rhizobial endophytes (NRE) and their role inside the root nodules are being explored; there is no evidence on yeast microflora inhabiting nodule niche. This study focused on unraveling the presence of yeast in the root nodules and their possible function in either nodulation or signal exchange. From the root nodules of blackgram, two yeast strains were isolated and identified as Candida glabrata VYP1 and Candida tropicalis VYW1 based on 18S rRNA gene sequencing and phylogeny. These strains possessed plant growth-promoting traits viz., IAA, ACC deaminase, siderophore, ammonia, and polyamine production. The functional capacity of endophytic yeast strains, and their interaction with Rhizobium sp. was further unveiled via profiling volatile organic compounds (VOC). Among the VOCs, α-glucopyranoside and pyrroloquinoline pitches a pivotal role in activating lectin pathways and phosphorous metabolism. Further, lectin pathways are crucial for nodulating bacterium, and our study showed that these endophytic yeasts assist nodulation by Rhizobium sp. via activating the nod factors. The plant growth-promoting traits of NRE yeast strains coupled with their metabolite production, could recruit them as potential drivers in the plant-microbe interaction.

RevDate: 2020-11-16
CmpDate: 2020-11-16

Reiter N, Phillips RD, Swarts ND, et al (2020)

Specific mycorrhizal associations involving the same fungal taxa in common and threatened Caladenia (Orchidaceae): implications for conservation.

Annals of botany, 126(5):943-955.

BACKGROUND AND AIMS: In orchid conservation, quantifying the specificity of mycorrhizal associations, and establishing which orchid species use the same fungal taxa, is important for sourcing suitable fungi for symbiotic propagation and selecting sites for conservation translocation. For Caladenia subgenus Calonema (Orchidaceae), which contains 58 threatened species, we ask the following questions. (1) How many taxa of Serendipita mycorrhizal fungi do threatened species of Caladenia associate with? (2) Do threatened Caladenia share orchid mycorrhizal fungi with common Caladenia? (3) How geographically widespread are mycorrhizal fungi associated with Caladenia?

METHODS: Fungi were isolated from 127 Caladenia species followed by DNA sequencing of the internal transcibed spacer (ITS) sequence locus. We used a 4.1-6 % sequence divergence cut-off range to delimit Serendipita operational taxonomic units (OTUs). We conducted trials testing the ability of fungal isolates to support germination and plant growth. A total of 597 Serendipita isolates from Caladenia, collected from across the Australian continent, were used to estimate the geographic range of OTUs.

KEY RESULTS: Across the genus, Caladenia associated with ten OTUs of Serendipita (Serendipitaceae) mycorrhizal fungi. Specificity was high, with 19 of the 23 threatened Caladenia species sampled in detail associating solely with OTU A, which supported plants from germination to adulthood. The majority of populations of Caladenia associated with one OTU per site. Fungal sharing was extensive, with 62 of the 79 Caladenia sampled in subgenus Calonema associating with OTU A. Most Serendipita OTUs were geographically widespread.

CONCLUSIONS: Mycorrhizal fungi can be isolated from related common species to propagate threatened Caladenia. Because of high specificity of most Caladenia species, only small numbers of OTUs typically need to be considered for conservation translocation. When selecting translocation sites, the geographic range of the fungi is not a limiting factor, and using related Caladenia species to infer the presence of suitable fungal OTUs may be feasible.

RevDate: 2020-11-16
CmpDate: 2020-11-16

Iversen KH, Rasmussen LH, Al-Nakeeb K, et al (2020)

Similar genomic patterns of clinical infective endocarditis and oral isolates of Streptococcus sanguinis and Streptococcus gordonii.

Scientific reports, 10(1):2728.

Streptococcus gordonii and Streptococcus sanguinis belong to the Mitis group streptococci, which mostly are commensals in the human oral cavity. Though they are oral commensals, they can escape their niche and cause infective endocarditis, a severe infection with high mortality. Several virulence factors important for the development of infective endocarditis have been described in these two species. However, the background for how the commensal bacteria, in some cases, become pathogenic is still not known. To gain a greater understanding of the mechanisms of the pathogenic potential, we performed a comparative analysis of 38 blood culture strains, S. sanguinis (n = 20) and S. gordonii (n = 18) from patients with verified infective endocarditis, along with 21 publicly available oral isolates from healthy individuals, S. sanguinis (n = 12) and S. gordonii (n = 9). Using whole genome sequencing data of the 59 streptococci genomes, functional profiles were constructed, using protein domain predictions based on the translated genes. These functional profiles were used for clustering, phylogenetics and machine learning. A clear separation could be made between the two species. No clear differences between oral isolates and clinical infective endocarditis isolates were found in any of the 675 translated core-genes. Additionally, random forest-based machine learning and clustering of the pan-genome data as well as amino acid variations in the core-genome could not separate the clinical and oral isolates. A total of 151 different virulence genes was identified in the 59 genomes. Among these homologs of genes important for adhesion and evasion of the immune system were found in all of the strains. Based on the functional profiles and virulence gene content of the genomes, we believe that all analysed strains had the ability to become pathogenic.

RevDate: 2020-11-17
CmpDate: 2020-11-17

Schuh NW, Carrier TJ, Schrankel CS, et al (2019)

Bacterial Exposure Mediates Developmental Plasticity and Resistance to Lethal Vibrio lentus Infection in Purple Sea Urchin (Strongylocentrotus purpuratus) Larvae.

Frontiers in immunology, 10:3014.

Exposure to and colonization by bacteria during development have wide-ranging beneficial effects on animal biology but can also inhibit growth or cause disease. The immune system is the prime mediator of these microbial interactions and is itself shaped by them. Studies using diverse animal taxa have begun to elucidate the mechanisms underlying the acquisition and transmission of bacterial symbionts and their interactions with developing immune systems. Moreover, the contexts of these associations are often confounded by stark differences between "wild type" microbiota and the bacterial communities associated with animals raised in conventional or germ-free laboratories. In this study, we investigate the spatio-temporal kinetics of bacterial colonization and associated effects on growth and immune function in larvae of the purple sea urchin (Strongylocentrotus purpuratus) as a model for host-microbe interactions and immune system development. We also compare the host-associated microbiota of developing embryos and larvae raised in natural seawater or exposed to adult-associated bacteria in the laboratory. Bacteria associated with zygotes, embryos, and early larvae are detectable with 16S amplicon sequencing, but 16S-FISH indicates that the vast majority of larval bacterial load is acquired after feeding begins and is localized to the gut lumen. The bacterial communities of laboratory-cultured embryos are significantly less diverse than the natural microbiota but recapitulate its major components (Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes), suggesting that biologically relevant host-microbe interactions can be studied in the laboratory. We also demonstrate that bacterial exposure in early development induces changes in morphology and in the immune system. In the absence of bacteria, larvae grow larger at the 4-arm stage. Additionally, bacteria-exposed larvae are significantly more resistant to lethal infection with the larva-associated pathogen Vibrio lentus suggesting that early exposure to high levels of microbes, as would be expected in natural conditions, affects the immune state in later larvae. These results expand our knowledge of microbial influences on early sea urchin development and establish a model in which to study the interactions between the developing larval immune system and the acquisition of larval microbiota.

RevDate: 2020-11-16
CmpDate: 2020-11-16

Li HW, Chen C, Kuo WL, et al (2019)

The Characteristics and Expression Profile of Transferrin in the Accessory Nidamental Gland of the Bigfin Reef Squid during Bacteria Transmission.

Scientific reports, 9(1):20163.

The accessory nidamental gland (ANG) is a female reproductive organ found in most squid and cuttlefish that contains a consortium of bacteria. These symbiotic bacteria are transmitted from the marine environment and selected by the host through an unknown mechanism. In animals, a common antimicrobial mechanism of innate immunity is iron sequestration, which is based on the development of transferrin (TF)-like proteins. To understand this mechanism of host-microbe interaction, we attempted to characterize the role of transferrin in bigfin reef squid (Sepioteuthis lessoniana) during bacterial transmission. qPCR analysis showed that Tf was exclusively expressed in the outer layer of ANG,and this was confirmed by in situ hybridization, which showed that Tf was localized in the outer epithelial cell layer of the ANG. Western blot analysis indicated that TF is a soluble glycoprotein. Immunohistochemical staining also showed that TF is localized in the outer epithelial cell layer of the ANG and that it is mainly expressed in the outer layer during ANG growth. These results suggest that robust Tf mRNA and TF protein expression in the outer layer of the ANG plays an important role in microbe selection by the host during bacterial transmission.

RevDate: 2020-11-16

Wood TE, Aksoy E, A Hachani (2020)

From Welfare to Warfare: The Arbitration of Host-Microbiota Interplay by the Type VI Secretion System.

Frontiers in cellular and infection microbiology, 10:587948.

The health of mammals depends on a complex interplay with their microbial ecosystems. Compartments exposed to external environments such as the mucosal surfaces of the gastrointestinal tract accommodate the gut microbiota, composed by a wide range of bacteria. The gut microbiome confers benefits to the host, including expansion of metabolic potential and the development of an immune system that can robustly protect from external and internal insults. The cooperation between gut microbiome and host is enabled in part by the formation of partitioned niches that harbor diverse bacterial phyla. Bacterial secretion systems are commonly employed to manipulate the composition of these local environments. Here, we explore the roles of the bacterial type VI secretion system (T6SS), present in ~25% of gram-negative bacteria, including many symbionts, in the establishment and perturbation of bacterial commensalism, and symbiosis in host mucosal sites. This versatile apparatus drives bacterial competition, although in some cases can also interfere directly with host cells and facilitate nutrient acquisition. In addition, some bacterial pathogens cause disease when their T6SS leads to dysbiosis and subverts host immune responses in defined animal models. This review explores our knowledge of the T6SS in the context of the "host-microbiota-pathogen" triumvirate and examines contexts in which the importance of this secretion system may be underappreciated.

RevDate: 2020-11-16

Arora G, Chaudhary D, Kidwai S, et al (2020)

Corrigendum: CitE Enzymes Are Essential for Mycobacterium tuberculosis to Establish Infection in Macrophages and Guinea Pigs.

Frontiers in cellular and infection microbiology, 10:587907.

[This corrects the article DOI: 10.3389/fcimb.2018.00385.].

RevDate: 2020-11-16

Qu YF, Wu YQ, Zhao YT, et al (2020)

The invasive red-eared slider turtle is more successful than the native Chinese three-keeled pond turtle: evidence from the gut microbiota.

PeerJ, 8:e10271 pii:10271.

Background: The mutualistic symbiosis between the gut microbial communities (microbiota) and their host animals has attracted much attention. Many factors potentially affect the gut microbiota, which also varies among host animals. The native Chinese three-keeled pond turtle (Chinemys reevesii) and the invasive red-eared slider turtle (Trachemys scripta elegans) are two common farm-raised species in China, with the latter generally considered a more successful species. However, supporting evidence from the gut microbiota has yet to be collected.

Methods: We collected feces samples from these two turtle species raised in a farm under identical conditions, and analyzed the composition and relative abundance of the gut microbes using bacterial 16S rRNA sequencing on the Roach/454 platform.

Results: The gut microbiota was mainly composed of Bacteroidetes and Firmicutes at the phylum level, and Porphyromonadaceae, Bacteroidaceae and Lachnospiraceae at the family level in both species. The relative abundance of the microbes and gene functions in the gut microbiota differed between the two species, whereas alpha or beta diversity did not. Microbes of the families Bacteroidaceae, Clostridiaceae and Lachnospiraceae were comparatively more abundant in C. reevesii, whereas those of the families Porphyromonadaceae and Fusobacteriaceae were comparatively more abundant in T. s. elegans. In both species the gut microbiota had functional roles in enhancing metabolism, genetic information processing and environmental information processing according to the Kyoto Encyclopedia of Genes and Genomes database. The potential to gain mass is greater in T. s. elegans than in C. reevesii, as revealed by the fact that the Firmicutes/Bacteroidetes ratio was lower in the former species. The percentage of human disease-related functional genes was lower in T. s. elegans than in C. reevesii, presumably suggesting an enhanced potential to colonize new habitats in the former species.

RevDate: 2020-11-16

Peng SE, Moret A, Chang C, et al (2020)

A shift away from mutualism under food-deprived conditions in an anemone-dinoflagellate association.

PeerJ, 8:e9745 pii:9745.

The mutualistic symbiosis between anthozoans and intra-gastrodermal dinoflagellates of the family Symbiodiniaceae is the functional basis of all coral reef ecosystems, with the latter providing up to 95% of their fixed photosynthate to their hosts in exchange for nutrients. However, recent studies of sponges, jellyfish, and anemones have revealed the potential for this mutualistic relationship to shift to parasitism under stressful conditions. Over a period of eight weeks, we compared the physiological conditions of both inoculated and aposymbiotic anemones (Exaiptasia pallida) that were either fed or starved. By the sixth week, both fed groups of anemones were significantly larger than their starved counterparts. Moreover, inoculated and starved anemones tended to disintegrate into "tissue balls" within eight weeks, and 25% of the samples died; in contrast, starved aposymbiotic anemones required six months to form tissue balls, and no anemones from this group died. Our results show that the dinoflagellates within inoculated anemones may have posed a fatal metabolic burden on their hosts during starvation; this may be because of the need to prioritize their own metabolism and nourishment at the expense of their hosts. Collectively, our study reveals the potential of this dynamic symbiotic association to shift away from mutualism during food-deprived conditions.

RevDate: 2020-11-16

Maire J, Chouaia B, Zaidman-Rémy A, et al (2020)

Endosymbiosis morphological reorganization during metamorphosis diverges in weevils.

Communicative & integrative biology, 13(1):184-188 pii:1840707.

Virtually all animals associate with beneficial symbiotic bacteria. Whether and how these associations are modulated across a host's lifecycle is an important question in disentangling animal-bacteria interactions. We recently reported a case of complete morphological reorganization of symbiosis during metamorphosis of the cereal weevil, Sitophilus oryzae. In this model, the bacteriome, a specialized organ that houses the intracellular bacterium Sodalis pierantonius, undergoes a two-phase remodeling program synchronously driven by host and endosymbiont, resulting in a localization shift and the formation of multiple new bacteriomes. Here, we provide comparative data in a closely-related coleopteran, the red palm weevil Rhynchophorus ferrugineus, which is associated with the ancestral endosymbiont Nardonella. Using cell imaging experiments, we show that the red pal weevil bacteriome remains unchanged during metamorphosis, hence contrasting with what we reported in the cereal weevil S. oryzae. These findings highlight the complexity and divergence of host-symbiont interactions and their intertwining with host development, even in closely-related species. Abbreviations: DAPI: 4',6-diamidino-2-phenylindole; FISH: Fluorescence in situ hybridization; T3SS: Type III secretion system.

RevDate: 2020-11-16

Liu A, Ku YS, Contador CA, et al (2020)

The Impacts of Domestication and Agricultural Practices on Legume Nutrient Acquisition Through Symbiosis With Rhizobia and Arbuscular Mycorrhizal Fungi.

Frontiers in genetics, 11:583954.

Legumes are unique among plants as they can obtain nitrogen through symbiosis with nitrogen-fixing rhizobia that form root nodules in the host plants. Therefore they are valuable crops for sustainable agriculture. Increasing nitrogen fixation efficiency is not only important for achieving better plant growth and yield, but it is also crucial for reducing the use of nitrogen fertilizer. Arbuscular mycorrhizal fungi (AMF) are another group of important beneficial microorganisms that form symbiotic relationships with legumes. AMF can promote host plant growth by providing mineral nutrients and improving the soil ecosystem. The trilateral legume-rhizobia-AMF symbiotic relationships also enhance plant development and tolerance against biotic and abiotic stresses. It is known that domestication and agricultural activities have led to the reduced genetic diversity of cultivated germplasms and higher sensitivity to nutrient deficiencies in crop plants, but how domestication has impacted the capability of legumes to establish beneficial associations with rhizospheric microbes (including rhizobia and fungi) is not well-studied. In this review, we will discuss the impacts of domestication and agricultural practices on the interactions between legumes and soil microbes, focusing on the effects on AMF and rhizobial symbioses and hence nutrient acquisition by host legumes. In addition, we will summarize the genes involved in legume-microbe interactions and studies that have contributed to a better understanding of legume symbiotic associations using metabolic modeling.

RevDate: 2020-11-16

Cibils-Stewart X, Powell JR, Popay AJ, et al (2020)

Reciprocal Effects of Silicon Supply and Endophytes on Silicon Accumulation and Epichloë Colonization in Grasses.

Frontiers in plant science, 11:593198.

Cool season grasses associate asymptomatically with foliar Epichloë endophytic fungi in a symbiosis where Epichloë spp. protects the plant from a number of biotic and abiotic stresses. Furthermore, many grass species can accumulate large quantities of silicon (Si), which also alleviates a similar range of stresses. While Epichloë endophytes may improve uptake of minerals and nutrients, their impact on Si is largely unknown. Likewise, the effect of Si availability on Epichloë colonization remains untested. To assess the bidirectional relationship, we grew tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) hydroponically with or without Si. Grasses were associated with five different Epichloë endophyte strains [tall fescue: AR584 or wild type (WT); perennial ryegrass: AR37, AR1, or WT] or as Epichloë-free controls. Reciprocally beneficial effects were observed for tall fescue associations. Specifically, Epichloë presence increased Si concentration in the foliage of tall fescue by at least 31%, regardless of endophyte strain. In perennial ryegrass, an increase in foliar Si was observed only for plants associated with the AR37. Epichloë promotion of Si was (i) independent of responses in plant growth, and (ii) positively correlated with endophyte colonization, which lends support to an endophyte effect independent of their impacts on root growth. Moreover, Epichloë colonization in tall fescue increased by more than 60% in the presence of silicon; however, this was not observed in perennial ryegrass. The reciprocal benefits of Epichloë-endophytes and foliar Si accumulation reported here, especially for tall fescue, might further increase grass tolerance to stress.

RevDate: 2020-11-16

Wu Z, Huang W, Qin E, et al (2020)

Comprehensive Identification and Expression Profiling of Circular RNAs During Nodule Development in Phaseolus vulgaris.

Frontiers in plant science, 11:587185.

Symbiotic nitrogen fixation by legume nodules provides an abundant nitrogen source for plants, and understanding this process is key for developing green agriculture. Circular RNA (circRNA), a type of endogenous RNA produced by reverse splicing of mRNA precursors, plays important regulatory roles in plants at the transcriptional and post-transcriptional levels. However, the relationship between circRNAs and legume-rhizobium is unknown. Here, we performed comprehensive identification and expression profiling of circRNAs during nodulation in common bean (Phaseolus vulgaris) compared to uninoculated roots of corresponding ages by constructing circRNA-seq and mRNA-seq libraries. We identified 8,842 high-confident circRNAs, 3,448 of which were specifically produced during symbiosis, with the highest number at the nitrogen-fixing stage. Significantly, more circRNAs were derived from exons than from intergenic regions or introns in all samples. The lengths and GC contents of the circRNAs were similar in roots and nodules. However, circRNAs showed specific spatiotemporal expression patterns during nodule and root development. GO and other functional annotation of parental genes of differentially expressed circRNAs indicated their potential involvement in different biological processes. The expression of major circRNAs during symbiosis is independent of parental genes' expression to a certain degree, while expression of the remaining minor circRNAs showed positive correlation to parental genes. Functional annotation of the targeted mRNAs in the circRNA-miRNA-mRNA network showed that circRNAs may be involved in transmembrane transport and positive regulation of kinase activity during nodulation and nitrogen fixation as miRNA sponges. Our comprehensive analysis of the expression profile of circRNAs and their potential functions suggests that circRNAs may function as new post-transcriptional regulators in legume-rhizobium symbiosis.

RevDate: 2020-11-16

Hirota B, Meng XY, T Fukatsu (2020)

Bacteriome-Associated Endosymbiotic Bacteria of Nosodendron Tree Sap Beetles (Coleoptera: Nosodendridae).

Frontiers in microbiology, 11:588841.

The family Nosodendridae is a small group of tree sap beetles with only 91 described species representing three genera from the world. In 1930s, bacteria-harboring symbiotic organs, called bacteriomes, were briefly described in a European species Nosodendron fasciculare. Since then, however, no studies have been conducted on the nosodendrid endosymbiosis for decades. Here we investigated the bacteriomes and the endosymbiotic bacteria of Nosodendron coenosum and Nosodendron asiaticum using molecular phylogenetic and histological approaches. In adults and larvae, a pair of slender bacteriomes were found along both sides of the midgut. The bacteriomes consisted of large bacteriocytes at the center and flat sheath cells on the surface. Fluorescence in situ hybridization detected preferential localization of the endosymbiotic bacteria in the cytoplasm of the bacteriocytes. In reproductive adult females, the endosymbiotic bacteria were also detected at the infection zone in the ovarioles and on the surface of growing oocytes, indicating vertical symbiont transmission via ovarial passage. Transmission electron microscopy unveiled bizarre structural features of the bacteriocytes, whose cytoplasm exhibited degenerate cytology with deformed endosymbiont cells. Molecular phylogenetic analysis revealed that the nosodendrid endosymbionts formed a distinct clade in the Bacteroidetes. The nosodendrid endosymbionts were the most closely related to the bacteriome endosymbionts of bostrichid powderpost beetles and also allied to the bacteriome endosymbionts of silvanid grain beetles, uncovering an unexpected endosymbiont relationship across the unrelated beetle families Nosodendridae, Bostrichidae and Silvanidae. Host-symbiont co-evolution and presumable biological roles of the endosymbiotic bacteria are discussed.

RevDate: 2020-11-16

Compton KK, Hildreth SB, Helm RF, et al (2020)

An Updated Perspective on Sinorhizobium meliloti Chemotaxis to Alfalfa Flavonoids.

Frontiers in microbiology, 11:581482.

The symbiotic interaction between leguminous plants and their cognate rhizobia allows for the fixation of gaseous dinitrogen into bioavailable ammonia. The perception of host-derived flavonoids is a key initial step for the signaling events that must occur preceding the formation of the nitrogen-fixing organ. Past work investigating chemotaxis - the directed movement of bacteria through chemical gradients - of Bradyrhizobium japonicum, Rhizobium leguminosarum, and Rhizobium meliloti discovered chemotaxis to various organic compounds, but focused on chemotaxis to flavonoids because of their relevance to the symbiosis biochemistry. The current work sought to replicate and further examine Sinorhizobium (Ensifer) meliloti chemotaxis to the flavonoids previously thought to act as the principal attractant molecules prior to the initial signaling stage. Exudate from germinating alfalfa seedlings was analyzed for composition and quantities of different flavonoid compounds using mass spectrometry. The abundance of four prevalent flavonoids in germinating alfalfa seed exudates (SEs) was at a ratio of 200:5:5:1 for hyperoside, luteolin, luteolin-7-glucoside, and chrysoeriol. Using quantitative chemotaxis capillary assays, we did not detect chemotaxis of motile S. meliloti cells to these, and two other flavonoids identified in seed exudates. In support of these findings, the flavonoid fraction of seed exudates was found to be an insignificant attractant relative to the more hydrophilic fraction. Additionally, we observed that cosolvents commonly used to dissolve flavonoids confound the results. We propose that the role flavonoids play in S. meliloti chemotaxis is insignificant relative to other components released by alfalfa seeds.

RevDate: 2020-11-16

Maruyama S, VM Weis (2020)

Limitations of using cultured algae to study cnidarian-algal symbioses and suggestions for future studies.

Journal of phycology [Epub ahead of print].

Much of our understanding of the cellular mechanisms underlying cnidarian-algal symbiosis comes from comparing the biology of the partners when they are engaged in symbiosis with when they are isolated from one another. When comparing the in hospite and ex hospite state in Symbiodiniaceae, the in hospite state is represented by algae sampled from hosts, and the ex hospite state is commonly represented by cultured algae. The use of cultured algae in this comparison may introduce nutrition as a confounding variable because, while hosts are kept in nutrient depleted conditions, culture media is nutrient rich and designed to facilitate algal growth. In this perspective, we reexamine how nutrition may be a confounding variable in studies that compare the biology of Symbiodiniaceae in hospite and in culture. We also suggest several innovations in experimental design to strengthen the comparison of the two lifestyles, including the adoption of nutritional controls, alternatives to culture for the representation of Symbiodiniaceae ex hospite, and the adoption of several proteomic approaches to find novel Symbiodiniaceae genes important for symbiosis.

RevDate: 2020-11-16

Singh P, Itankar N, Y Patil (2020)

Biomanagement of hexavalent chromium: Current trends and promising perspectives.

Journal of environmental management pii:S0301-4797(20)31472-9 [Epub ahead of print].

Chromium (Cr) is most widely used heavy metal with vast applications in industrial sectors such as metallurgy, automobile, leather, electroplating, etc. Subsequently, these industries discharge large volumes of toxic Cr containing industrial wastewaters without proper treatment/management into the environment, causing severe damage to human health and ecology. This review gives some novel insights on the existing, successful and promising bio-based approaches for Cr remediation. In lieu of the multiple limitations of the physical and chemical methods for remediation, various biological means have been deciphered, wherein dead and live biomass have shown immense capabilities of removing/reducing and/or remediating Cr from polluted environmental niches. Adsorption of Cr by various agro-based waste and reduction/precipitation by different microbial groups have shown promising results in chromium removal/recovery. Various microbial based agents and aquatic plants like duckweeds are emerging as efficient adsorbents of metals and their role in chromium bioremediation is an effective green technology that needs to be harnessed effectively. The role of iron and sulphur reducing bacteria have shown potential for enhanced Cr remediation. Biosurfactants have revealed immense scope as enhancers of microbial metal bioremediation and have been reported to have potential for use in chromium recovery as well. The authors also explore the combined use of biochar and biosurfactants as a potential strategy for chromium bioremediation for the development of technology worth adopting. Cr is non-renewable and finite resource, therefore its safe removal/recovery from wastes is of major significance for achieving social, economic and environmental sustainability.

RevDate: 2020-11-15

Mohamed AYA, Welles L, Siggins A, et al (2020)

Effects of substrate stress and light intensity on enhanced biological phosphorus removal in a photo-activated sludge system.

Water research, 189:116606 pii:S0043-1354(20)31141-6 [Epub ahead of print].

Photo-activated sludge (PAS) systems are an emerging wastewater treatment technology where microalgae provide oxygen to bacteria without the need for external aeration. There is limited knowledge on the optimal conditions for enhanced biological phosphorus removal (EBPR) in systems containing a mixture of polyphosphate accumulating organisms (PAOs) and microalgae. This research aimed to study the effects of substrate composition and light intensity on the performance of a laboratory-scale EBPR-PAS system. Initially, a model-based design was developed to study the effect of organic carbon (COD), inorganic carbon (HCO3) and ammonium-nitrogen (NH4-N) in nitrification deprived conditions on phosphorus (P) removal. Based on the mathematical model, two different synthetic wastewater compositions (COD:HCO3:NH4-N: 10:20:1 and 10:10:4) were examined at a light intensity of 350 µmol m-2 sec-1. Add to this, the performance of the system was also investigated at light intensities: 87.5, 175, and 262.5 µmol m-2 sec-1 for short terms. Results showed that wastewater having a high level of HCO3 and low level of NH4-N (ratio of 10:20:1) favored only microalgal growth, and had poor P removal due to a shortage of NH4-N for PAOs growth. However, lowering the HCO3 level and increasing the NH4-N level (ratio of 10:10:4) balanced PAOs and microalgae symbiosis, and had a positive influence on P removal. Under this mode of operation, the system was able to operate without external aeration and achieved a net P removal of 10.33 ±1.45 mg L-1 at an influent COD of 100 mg L-1. No significant variation was observed in the reactor performance for different light intensities, indicating the EBPR-PAS system can be operated at low light intensities with a positive influence on P removal.

RevDate: 2020-11-15

Wang G, Wang L, Ma F, et al (2020)

Earthworm and arbuscular mycorrhiza interactions: Strategies to motivate antioxidant responses and improve soil functionality.

Environmental pollution (Barking, Essex : 1987) pii:S0269-7491(20)36669-0 [Epub ahead of print].

Earthworms and arbuscular mycorrhizal fungi (AMF) act synergistically in the rhizosphere and may increase host plant tolerance to Cd. However, mechanisms by which earthworm-AMF-plant partnerships counteract Cd phytotoxicity are unknown. Thus, we evaluated individual and interactive effects of these soil organisms on photosynthesis, antioxidant capacity, and essential nutrient uptake by Solanum nigrum, as well as on soil quality following Cd exposure (0-120 mg kg-1). Decreases in biomass and photosynthetic activity, as well as nutrient imbalances were observed in Cd-stressed plants; however, the addition of AMF and earthworms reversed these effects. Cd exposure increased superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, whereas inoculation with Rhizophagus intraradices decreased those. Soil enzymatic activity decreased by 15-60% with increasing Cd concentrations. However, Cd-mediated toxicity was partially reversed by soil organisms. Earthworms and AMF ameliorated soil quality based on soil enzyme activity. At 120 mg kg-1 Cd, the urease, catalase, and acid phosphatase activities were 1.6-, 1.4-, and 1.2-fold higher, respectively, in soils co-incubated with earthworms and AMF than in uninoculated soil. Cd inhibited shoot Fe and Ca phytoaccumulation, whereas AMF and earthworms normalized the status of essential elements in plants. Cd detoxification by earthworm-AMF-S. nigrum symbiosis was manifested by increases in plant biomass accumulation (22-117%), chlorophyll content (17-63%), antioxidant levels (SOD 10-18%, POD 9-25%, total polyphenols 17-22%, flavonoids 15-29%, and glutathione 7-61%). It also ameliorated the photosynthetic capacity, and macro- and micronutrient statuses of plants; markedly reduced the levels of malondialdehyde (20-27%), superoxide anion (29-36%), and hydrogen peroxide (19-30%); and upregulated the transcription level of FeSOD. Thus, the combined action of earthworms and AMF feasibly enhances metal tolerance of hyperaccumulating plants and improves the quality of polluted soil.

RevDate: 2020-11-14

Ma X, Geng Q, Zhang H, et al (2020)

Global negative effects of nutrient enrichment on arbuscular mycorrhizal fungi, plant diversity and ecosystem multi-functionality.

The New phytologist [Epub ahead of print].

Despite widespread anthropogenic nutrient enrichment, it remains unclear how nutrient enrichment influences plant- arbuscular mycorrhizal fungi (AMF) symbiosis and ecosystem multi-functionality at the global scale. Here, we conducted a meta-analysis to examine the worldwide effects of nutrient enrichment on AMF and plant diversity and ecosystem multi-functionality using data of field experiments from 136 papers. Our analyses showed that nutrient addition simultaneously decreased AMF diversity and abundance belowground and plant diversity aboveground at the global scale. The decreases in AMF diversity and abundance associated with nutrient addition were more pronounced with increasing experimental duration, mean annual temperature (MAT) and mean annual precipitation (MAP). Nutrient addition-induced changes in soil pH and available phosphorus (P) predominantly regulated the responses of AMF diversity and abundance. Furthermore, AMF diversity correlated with ecosystem multi-functionality under nutrient addition worldwide. Our findings identify the negative effects of nutrient enrichment on AMF and plant diversity and suggest that AMF diversity is closely linked with ecosystem function. This study offers an important advancement in our understanding of plant-AMF interactions and their likely responses to ongoing global change.

RevDate: 2020-11-16

Shelomi M, MJ Chen (2020)

Culturing-Enriched Metabarcoding Analysis of the Oryctes rhinoceros Gut Microbiome.

Insects, 11(11): pii:insects11110782.

Wood-feeding insects should have a source of enzymes like cellulases to digest their food. These enzymes can be produced by the insect, or by microbes living in the wood and/or inside the insect gut. The coconut rhinoceros beetle, Oryctes rhinoceros, is a pest whose digestive microbes are of considerable interest. This study describes the compartments of the O. rhinoceros gut and compares their microbiomes using culturing-enriched metabarcoding. Beetle larvae were collected from a coconut grove in southern Taiwan. Gut contents from the midgut and hindgut were plated on nutrient agar and selective carboxymethylcellulose agar plates. DNA was extracted from gut and fat body samples and 16S rDNA metabarcoding performed to identify unculturable bacteria. Cellulase activity tests were performed on gut fluids and microbe isolates. The midgut and hindgut both showed cellulolytic activity. Bacillus cereus, Citrobacter koseri, and the cellulolytic fungus Candida xylanilytica were cultured from both gut sections in most larvae. Metabarcoding did not find Bacillus cereus, and found that either Citrobacter koseri or Paracoccus sp. were the dominant gut microbes in any given larva. No significant differences were found between midgut and hindgut microbiomes. Bacillus cereus and Citrobacter koseri are common animal gut microbes frequently found in Oryctes rhinoceros studies while Candida xylanilytica and the uncultured Paracoccus sp. had not been identified in this insect before. Some or all of these may well have digestive functions for the beetle, and are most likely acquired from the diet, meaning they may be transient commensalists rather than obligate mutualists. Broader collection efforts and tests with antibiotics will resolve ambiguities in the beetle-microbe interactions.

RevDate: 2020-11-13

Yoshioka Y, Yamashita H, Suzuki G, et al (2020)

Whole-genome transcriptome analyses of native symbionts reveal host coral genomic novelties for establishing coral-algae symbioses.

Genome biology and evolution pii:5981117 [Epub ahead of print].

Reef-building corals and photosynthetic, endosymbiotic algae of the family Symbiodiniaceae establish mutualistic relationships that are fundamental to coral biology, enabling coral reefs to support a vast diversity of marine species. Although numerous types of Symbiodiniaceae occur in coral reef environments, Acropora corals select specific types in early life stages. In order to study molecular mechanisms of coral-algal symbioses occurring in nature, we performed whole-genome transcriptomic analyses of Acropora tenuis larvae inoculated with Symbiodinium microadriaticum strains isolated from Acropora. In order to identify genes specifically involved in symbioses with native symbionts in early life stages, we also investigated transcriptomic responses of Acropora larvae exposed to closely related, non-symbiotic, and occasionally symbiotic Symbiodinium strains. We found that the number of differentially expressed genes was largest when larvae acquired native symbionts. Repertoires of differentially expressed genes indicated that corals reduced amino acid, sugar, and lipid metabolism, such that metabolic enzymes performing these functions were derived primarily from S. microadriaticum rather than from A. tenuis. Up-regulated gene expression of transporters for those metabolites occurred only when coral larvae acquired their natural symbionts, suggesting active utilization of native symbionts by host corals. We also discovered that in Acropora, genes for sugar and amino acid transporters, prosaposin-like, and Notch ligand-like, were up-regulated only in response to native symbionts, and included tandemly duplicated genes. Gene duplications in coral genomes may have been essential to establish genomic novelties for coral-algae symbiosis.

RevDate: 2020-11-16
CmpDate: 2020-11-16

Bukharin OV, Kuzmin MD, Perunova NB, et al (2020)

[Characterization of the microbiota and cytokine profile of sperm plasma in men with chronic bacterial prostatitis].

Urologiia (Moscow, Russia : 1999).

BACKGROUND: One of the leading causes of the occurrence of chronic bacterial prostatitis (CBP) in men is infection, microecological disorders of the urogenital tract and cytokine-mediated mechanisms of inflammation of the prostate gland, which actualizes a comprehensive study of the clinical and bacteriological features of CBP from the perspective of a symbiotic approach in the framework of a new scientific field - "infectious symbiology".

OBJECTIVE: to study the characteristics of spermogram, microbiota, and the cytokine profile in men with chronic bacterial prostatitis (CBP) and CBP complicated by infertility.

MATERIALS AND METHODS: A comprehensive study of patients with CBP and CBP complicated by infertility, in comparison with conditionally healthy individuals, was conducted. Species identification of microorganisms was carried out according to biochemical characteristics and the genetic method (sequencing of strains). The biological properties of the microbiota were evaluated: growth properties, biofilm formation, antipeptide activity against the cytokines IL-10, RAIL-1, TNF-, INF- and IL-17 (8 parameters). Immunological parameters of sperm plasma included 13 parameters: the content of cytokines TNF-, INF-, Rail, interleukins (IL) -1, 2, 4, 6, 8, 10, 17, immunoglobulin (Ig) A, lactoferrin and lysozyme. To evaluate sperm plasma, the following quantities were determined: ejaculate volume, pH, sperm plasma liquefaction, total sperm count, sperm count per 1 ml, motility, number of progressively motile, non-progressive motile and motionless spermatozoa, number of round cells, white blood cells, spermatogenesis cells, erythrocytes, erythrocytes, cells, sperm agglutination and aggregation (16 parameters in total). The results are statistically processed.

RESULTS: Data were obtained on changes in biofilm formation, antipeptide activity of microbiota (especially pronounced in corynebacteria), sperm plasma cytokine profile (increased TNF , IL-2, 6, 17), as well as IgA and lactoferrin, which can be used to build a prognostic model of reproductive pathology tract of men and their fertile activity.

CONCLUSION: The study of the antipeptide activity of microbiota in combination with the cytokine profile of ejaculate allows us to recommend them as a "biotarget" for diagnostic, preventive and therapeutic measures for chronic prostatitis in men, which contribute to solving the medical and social problem of preventing male infertility and contributes to the development of health-saving technologies with incorporating elements of personalized medicine.

RevDate: 2020-11-13

Braunberger P (2020)

Symbiosis and survival: Xanthoria elegans.

Journal of the Canadian Academy of Child and Adolescent Psychiatry = Journal de l'Academie canadienne de psychiatrie de l'enfant et de l'adolescent, 29(4):256-259.

RevDate: 2020-11-13

Kagawa O, Uchida S, Yamazaki D, et al (2020)

Citizen science via social media revealed conditions of symbiosis between a marine gastropod and an epibiotic alga.

Scientific reports, 10(1):19647 pii:10.1038/s41598-020-74946-5.

Environmental factors promote symbiosis, but its mechanism is not yet well understood. The alga Pseudocladophora conchopheria grows only on the shell of an intertidal gastropod Lunella correensis, and these species have a close symbiotic relationship which the alga reduces heat stress of the gastropod. In collaboration with general public, we investigated how environmental conditions alter the symbiotic interaction between the alga and the gastropod. Information about the habitats of each gastropod and images of shells was obtained from the Japanese and Korean coasts via social media. We constructed the hierarchical Bayesian model using the data. The results indicated that the proportion of shell area covered by P. conchopheria increased as the substrate size utilized by the gastropod increased. Meanwhile, temperature did not affect the proportion of P. conchopheria on the shell. These suggested that the alga provides no benefits for the gastropod on small substrates because gastropod can reduce the heat stress by diving into the small sediment. Further, the gastropod's cost incurred by growing the alga on the shell seems to be low as the algae can grow even in cooler places where no benefits of heat resistance for gastropods. Different environments can yield variable conditions in symbiosis.

RevDate: 2020-11-13

Yuan S, Ke D, Li R, et al (2020)

Genome-wide survey of soybean papain-like cysteine proteases and their expression analysis in root nodule symbiosis.

BMC plant biology, 20(1):517 pii:10.1186/s12870-020-02725-5.

BACKGROUND: Plant papain-like cysteine proteases (PLCPs) are a large class of proteolytic enzymes and play important roles in root nodule symbiosis (RNS), while the whole-genome studies of PLCP family genes in legume are quite limited, and the roles of Glycine max PLCPs (GmPLCPs) in nodulation, nodule development and senescence are not fully understood.

RESULTS: In the present study, we identified 97 GmPLCPs and performed a genome-wide survey to explore the expansion of soybean PLCP family genes and their relationships to RNS. Nineteen paralogous pairs of genomic segments, consisting of 77 GmPLCPs, formed by whole-genome duplication (WGD) events were identified, showing a high degree of complexity in duplication. Phylogenetic analysis among different species showed that the lineage differentiation of GmPLCPs occurred after family expansion, and large tandem repeat segment were specifically in soybean. The expression patterns of GmPLCPs in symbiosis-related tissues and nodules identified RNS-related GmPLCPs and provided insights into their putative symbiotic functions in soybean. The symbiotic function analyses showed that a RNS-related GmPLCP gene (Glyma.04G190700) really participate in nodulation and nodule development.

CONCLUSIONS: Our findings improved our understanding of the functional diversity of legume PLCP family genes, and provided insights into the putative roles of the legume PLCPs in nodulation, nodule development and senescence.

RevDate: 2020-11-13
CmpDate: 2020-11-13

Ramin E, Bestuzheva K, Gargalo CL, et al (2021)

Incremental design of water symbiosis networks with prior knowledge: The case of an industrial park in Kenya.

The Science of the total environment, 751:141706.

Industrial parks have a high potential for recycling and reusing resources such as water across companies by creating symbiosis networks. In this study, we introduce a mathematical optimization framework for the design of water network integration in industrial parks formulated as a large-scale standard mixed-integer non-linear programming (MINLP) problem. The novelty of our approach relies on i) developing a multi-level incremental optimization framework for water network synthesis, ii) including prior knowledge of water demand growth and projected water scarcity to evaluate the significance of water-saving solutions, iii) incorporating a comprehensive formulation of the water network synthesis problem including multiple pollutants and different treatment units and iv) performing a multi-objective optimization of the network including freshwater savings and relative cost of the network. The significance of the proposed optimization framework is illustrated by applying it to an existing industrial park in a water-scarce region in Kenya. Firstly, we illustrated the benefits of including prior knowledge to prevent an over-design of the network at the early stages. In the case study, we achieved a more flexible and expandable water network with 36% lower unit cost at the early stage and 15% lower unit cost at later stages for overall maximum freshwater savings of 25%. Secondly, multi-objective analysis suggests an optimum freshwater savings of 14% to reduce the unit cost of the network by half. Moreover, the significance of symbiosis networks is highlighted by showing that intra-company connections can only achieve a maximum freshwater savings of 17% with significantly higher unit cost (+45%). Finally, we showed that the values of symbiosis connectivity index in the Pareto front correspond to higher freshwater savings, indicating the significant role of the symbiosis network in the industrial park under study. This is the first study, where all the above elements have been taken into account simultaneously for the design of a water reuse network.

RevDate: 2020-11-13
CmpDate: 2020-11-13

Rivera MJ, Martini X, Conover D, et al (2020)

Evaluation of semiochemical based push-pull strategy for population suppression of ambrosia beetle vectors of laurel wilt disease in avocado.

Scientific reports, 10(1):2670.

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) bore into tree xylem to complete their life cycle, feeding on symbiotic fungi. Ambrosia beetles are a threat to avocado where they have been found to vector a symbiotic fungus, Raffaelea lauricola, the causal agent of the laurel wilt disease. We assessed the repellency of methyl salicylate and verbenone to two putative laurel wilt vectors in avocado, Xyleborus volvulus (Fabricius) and Xyleborus bispinatus (Eichhoff), under laboratory conditions. Then, we tested the same two chemicals released from SPLAT flowable matrix with and without low-dose ethanol dispensers for manipulation of ambrosia beetle populations occurring in commercial avocado. The potential active space of repellents was assessed by quantifying beetle catch on traps placed 'close' (~5-10 cm) and 'far' (~1-1.5 m) away from repellent dispensers. Ambrosia beetles collected on traps associated with all in-field treatments were identified to species to assess beetle diversity and community variation. Xyleborus volvulus was not repelled by methyl salicylate (MeSA) or verbenone in laboratory assays, while X. bispinatus was repelled by MeSA but not verbenone. Ambrosia beetle trap catches were reduced in the field more when plots were treated with verbenone dispensers (SPLAT) co-deployed with low-dose ethanol dispensers than when treated with verbenone alone. Beetle diversity was highest on traps deployed with low-dose ethanol lures. The repellent treatments and ethanol lures significantly altered the species composition of beetles captured in experiment plots. Our results indicate that verbenone co-deployed with ethanol lures holds potential for manipulating ambrosia beetle vectors via push-pull management in avocado. This tactic could discourage immigration and/or population establishment of ambrosia beetles in commercial avocado and function as an additional tool for management programs of laurel wilt.

RevDate: 2020-11-12

Tahayori B (2020)

Prokaryote-Eukaryote Symbiosis to Produce RNA-Based Therapeutics.

Frontiers in genetics, 11:583464.

RevDate: 2020-11-12

Bengoa AA, Dardis C, Gagliarini N, et al (2020)

Exopolysaccharides From Lactobacillus paracasei Isolated From Kefir as Potential Bioactive Compounds for Microbiota Modulation.

Frontiers in microbiology, 11:583254.

Microbiota coexists in true symbiosis with the host playing pivotal roles as a key element for well-being and health. Exopolysaccharides from lactic acid bacteria are an alternative as novel potential prebiotics that increase microbiota diversity. Considering this, the aim of the present work was to evaluate the capacity of the EPS produced by two L. paracasei strains isolated from kefir grains, to be metabolized in vitro by fecal microbiota producing short chain fatty acids. For this purpose, fecal samples from healthy children were inoculated in a basal medium with EPS and incubated in anaerobiosis at 37°C for 24, 48, and 72 h. DGGE profiles and the production of SCFA after fermentation were analyzed. Additionally, three selected samples were sequenced by mass sequencing analysis using Ion Torrent PGM. EPS produced by L. paracasei CIDCA 8339 (EPS8339) and CIDCA 83124 (EPS83124) are metabolized by fecal microbiota producing a significant increase in SCFA. EPS8339 fermentation led to an increment of propionate and butyrate, while fermentation of EPS83124 increased butyrate levels. Both EPS led to a profile of SCFA different from the ones obtained with inulin or glucose fermentation. DGGE profiles of 72 h fermentation demonstrated that both EPS showed a different band profile when compared to the controls; EPS profiles grouped in a cluster that have only 65% similarity with glucose or inulin profiles. Mass sequencing analysis demonstrated that the fermentation of EPS8339 leads to an increase in the proportion of the genera Victivallis, Acidaminococcus and Comamonas and a significant drop in the proportion of enterobacteria. In the same direction, the fermentation of EPS83124 also resulted in a marked reduction of Enterobacteriaceae with a significant increase in the genus Comamonas. It was observed that the changes in fecal microbiota and SCFA profile exerted by both polymers are different probably due to differences in their structural characteristics. It can be concluded that EPS synthesized by both L. paracasei strains, could be potentially used as bioactive compound that modify the microbiota increasing the production of propionic and butyric acid, two metabolites highly associated with beneficial effects both at the gastrointestinal and extra-intestinal level.

RevDate: 2020-11-12

Goto S, Ohbayashi T, Takeshita K, et al (2020)

A Peptidoglycan Amidase Mutant of Burkholderia insecticola Adapts an L-form-like Shape in the Gut Symbiotic Organ of the Bean Bug Riptortus pedestris.

Microbes and environments, 35(4):.

Bacterial cell shapes may be altered by the cell cycle, nutrient availability, environmental stress, and interactions with other organisms. The bean bug Riptortus pedestris possesses a symbiotic bacterium, Burkholderia insecticola, in its midgut crypts. This symbiont is a typical rod-shaped bacterium under in vitro culture conditions, but changes to a spherical shape inside the gut symbiotic organ of the host insect, suggesting the induction of morphological alterations in B. insecticola by host factors. The present study revealed that a deletion mutant of a peptidoglycan amidase gene (amiC), showing a filamentous chain form in vitro, adapted a swollen L-form-like cell shape in midgut crypts. Spatiotemporal observations of the ΔamiC mutant in midgut crypts revealed the induction of swollen cells, particularly prior to the molting of insects. To elucidate the mechanisms underlying in vivo-specific morphological alterations, the symbiont was cultured under 13 different conditions and its cell shape was examined. Swollen cells, similar to symbiont cells in midgut crypts, were induced when the mutant was treated with fosfomycin, an inhibitor of peptidoglycan precursor biosynthesis. Collectively, these results strongly suggest that the Burkholderia symbiont in midgut crypts is under the control of the host insect via a cell wall-attacking agent.

RevDate: 2020-11-12

Masson F, B Lemaitre (2020)

Growing Ungrowable Bacteria: Overview and Perspectives on Insect Symbiont Culturability.

Microbiology and molecular biology reviews : MMBR, 84(4):.

SUMMARYInsects are often involved in endosymbiosis, that is, the housing of symbiotic microbes within their tissues or within their cells. Endosymbionts are a major driving force in insects' evolution, because they dramatically affect their host physiology and allow them to adapt to new niches, for example, by complementing their diet or by protecting them against pathogens. Endosymbiotic bacteria are, however, fastidious and therefore difficult to manipulate outside of their hosts, especially intracellular species. The coevolution between hosts and endosymbionts leads to alterations in the genomes of endosymbionts, limiting their ability to cope with changing environments. Consequently, few insect endosymbionts are culturable in vitro and genetically tractable, making functional genetics studies impracticable on most endosymbiotic bacteria. However, recently, major progress has been made in manipulating several intracellular endosymbiont species in vitro, leading to astonishing discoveries on their physiology and the way they interact with their host. This review establishes a comprehensive picture of the in vitro tractability of insect endosymbiotic bacteria and addresses the reason why most species are not culturable. By compiling and discussing the latest developments in the design of custom media and genetic manipulation protocols, it aims at providing new leads to expand the range of tractable endosymbionts and foster genetic research on these models.

RevDate: 2020-11-11

Prasad S, Rajan A, Pasha SA, et al (2020)

Abnormal structural connectivity in progressive supranuclear palsy - Richardson syndrome.

Acta neurologica Scandinavica [Epub ahead of print].

OBJECTIVES: Progressive supranuclear palsy-Richardson syndrome (PSP-RS) is characterized by symmetrical parkinsonism with postural instability and frontal dysfunction. This study aims to use the whole brain structural connectome (SC) to gain insights into the underlying disconnectivity which may be implicated in the clinical features of PSP-RS.

METHODS: Sixteen patients of PSP-RS and 12 healthy controls were recruited. Disease severity was quantified using PSP rating scale (PSPRS), and mini-mental scale was applied to evaluate cognition. Thirty-two direction diffusion MRIs were acquired and used to compute the structural connectome of the whole brain using deterministic fiber tracking. Group analyses were performed at the edge-wise, nodal and global levels. Age and gender were used as nuisance covariates for all the subsequent analyses, and FDR correction was applied.

RESULTS: Network based statistics revealed a 34-edge network with significantly abnormal edge-wise connectivity in the patient group. Of these, 25 edges were cortical connections, of which 68% were frontal connections. Abnormal deep gray matter connections were predominantly comprised of connections between structures of the basal ganglia. The characteristic path length of the SC was lower in PSP-RS, and nodal analysis revealed abnormal degree, strength, local efficiency, betweenness centrality and participation coefficient in several nodes.

CONCLUSIONS: Significant alterations in the structural connectivity of the whole brain connectome were observed in PSP-RS. The higher degree of abnormality observed in nodes belonging to the frontal lobe and basal ganglia substantiates the predominant frontal dysfunction and parkinsonism observed in PSP-RS. The findings of this study support the concept that PSP-RS may be a network-based disorder.

RevDate: 2020-11-11

Avadhanam V, Ingavle G, Zheng Y, et al (2020)

Biomimetic bone-like composites as osteo-odonto-keratoprosthesis skirt substitutes.

Journal of biomaterials applications [Epub ahead of print].

Osteo-odonto-keratoprostheses, incorporating dental laminate material as an anchoring skirt around a central poly(methyl methacrylate) (PMMA) optic, have been used to replace the cornea for many years. However, there are many intricacies associated with the use of autologous dental laminate material, surgical complexity and skirt erosion. Tissue engineering approaches to bone replacement may offer suitable alternatives in osteo-odonto-keratoprosthesis (OOKP) surgery. In this study, a hydrogel polymer composite was investigated as a synthetic substitute for the OOKP skirt. A novel high strength interpenetrating network (IPN) hydrogel composite with nano-crystalline hydroxyapatite (nHAp) coated poly (lactic-co-glycolic acid) PLGA microspheres was created to mimic the alveo-dental lamina by employing agarose and poly(ethylene glycol) diacrylate (PEGDA) polymers. The incorporation of nHAp coated PLGA microspheres into the hybrid IPN network provide a micro-environment similar to that of skeletal tissues and improve cellular response. Agarose was used as a first network to encapsulate keratocytes/3T3 fibroblasts and PEGDA (6000 Da) was used as a second network with varying concentrations (20 and 40 wt %) to produce a strong and biocompatible scaffold. An increased concentration of either agarose or PEG-DA and incorporation of nHAp coated PLGA microspheres led to an increase in the elastic modulus. The IPN hydrogel combinations supported the adhesion and proliferation of both fibroblast and ocular human keratocyte cell types during in in-vitro testing. The cells endured the encapsulation process into the IPN and remained viable at 1 week post-encapsulation in the presence of nHAp coated microspheres. The material did not induce significant production of inflammatory cytokine IL-6 in comparison to a positive control (p < 0.05) indicating non-inflammatory potential. The nHAp encapsulated composite IPN hydrogels are mechanically strong, cell supportive, non-inflammatory materials supporting their development as OOKP skirt substitutes using a new approach to dental laminate biomimicry in the OOKP skirt material.

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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.

ESP Content

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.

ESP Help

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.

ESP Plans

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.

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @ gmail.com

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

ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.

Biographies

Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 07 JUL 2018 )