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Bibliography on: Metagenomics

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ESP: PubMed Auto Bibliography 22 Aug 2019 at 01:30 Created: 

Metagenomics

While genomics is the study of DNA extracted from individuals — individual cells, tissues, or organisms — metagenomics is a more recent refinement that analyzes samples of pooled DNA taken from the environment, not from an individual. Like genomics, metagenomic methods have great potential in many areas of biology, but none so much as in providing access to the hitherto invisible world of unculturable microbes, often estimated to comprise 90% or more of bacterial species and, in some ecosystems, the bulk of the biomass. A recent describes how this new science of metagenomics is beginning to reveal the secrets of our microbial world: The opportunity that stands before microbiologists today is akin to a reinvention of the microscope in the expanse of research questions it opens to investigation. Metagenomics provides a new way of examining the microbial world that not only will transform modern microbiology but has the potential to revolutionize understanding of the entire living world. In metagenomics, the power of genomic analysis is applied to entire communities of microbes, bypassing the need to isolate and culture individual bacterial community members.

Created with PubMed® Query: metagenomic OR metagenomics OR metagenome NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2019-08-20

Alves LF, Borelli TC, Westmann CA, et al (2019)

[PROVISIONAL] Boundaries in metagenomic screenings using lacZα-based vectors.

Genetics and molecular biology pii:S1415-47572019005031101 [Epub ahead of print].

Metagenomics approaches have been of high relevance for providing enzymes used in diverse industrial applications. In the current study, we have focused on the prospection of protease and glycosyl hydrolase activities from a soil sample by using the lacZα -based plasmid pSEVA232. For this, we used a functional screen based on skimmed milk agar and a pH indicator dye for detection of both enzymes, as previously reported in literature. Although we effectively identified positive clones in the screenings, subsequent experiments revealed that this phenotype was not because of the hydrolytic activity encoded in the metagenomic fragments, but rather due to the insertion of small metagenomic DNA fragments in frame within the coding region of the lacZ gene present in the original vector. Analyses of the thermodynamic stability of mRNA secondary structures indicated that recovering of positive clones was probably due to higher expression levels of the chimeric lacZα-genes in respect to the original from empty vector. We concluded that this method has a higher tendency for recovery false positive clones, when used in combination with a lacZα-based vector. As these vectors are massively used in functional metagenomic screenings, we highlight the importance of reporting boundaries in established metagenomic screenings methodologies.

RevDate: 2019-08-20

Casimiro-Soriguer CS, Loucera C, Perez Florido J, et al (2019)

Antibiotic resistance and metabolic profiles as functional biomarkers that accurately predict the geographic origin of city metagenomics samples.

Biology direct, 14(1):15 pii:10.1186/s13062-019-0246-9.

BACKGROUND: The availability of hundreds of city microbiome profiles allows the development of increasingly accurate predictors of the origin of a sample based on its microbiota composition. Typical microbiome studies involve the analysis of bacterial abundance profiles.

RESULTS: Here we use a transformation of the conventional bacterial strain or gene abundance profiles to functional profiles that account for bacterial metabolism and other cell functionalities. These profiles are used as features for city classification in a machine learning algorithm that allows the extraction of the most relevant features for the classification.

CONCLUSIONS: We demonstrate here that the use of functional profiles not only predict accurately the most likely origin of a sample but also to provide an interesting functional point of view of the biogeography of the microbiota. Interestingly, we show how cities can be classified based on the observed profile of antibiotic resistances.

REVIEWERS: Open peer review: Reviewed by Jin Zhuang Dou, Jing Zhou, Torsten Semmler and Eran Elhaik.

RevDate: 2019-08-20

Yue S, He T, Li B, et al (2019)

Effectiveness of Yi-Zhi-An-Shen granules on cognition and sleep quality in older adults with amnestic mild cognitive impairment: protocol for a randomized, double-blind, placebo-controlled trial.

Trials, 20(1):518 pii:10.1186/s13063-019-3607-x.

BACKGROUND: Amnestic mild cognitive impairment (aMCI) is a syndrome characterized by significant forgetfulness that does not meet the criteria of dementia. Individuals with aMCI are at greater risk of progressing to dementia. Current studies suggest that good sleep quality is linked with preserved cognition in the elderly, and sleep complaints are common among the elderly with amnesia. Therefore, improving their sleep may be helpful for maintaining and improving their cognitive capacity. According to the theory of traditional Chinese medicine, Yi-Zhi-An-Shen is an herbal compound which may ameliorate forgetfulness and sleep disorders. As growing evidence indicates that the gut microbiome is associated with major mental symptoms, a hypothesis was proposed that Yi-Zhi-An-Shen granules (YZASG) might work by alternating microbial abundance and diversity. In this study, the investigators intend to assess the efficacy of YZASG on global cognition in the elderly suffering from aMCI and evaluate its safety as well as its potential mechanisms via sleep quality, fecal microbial 16S ribosomal DNA and metagenomics analyses, and serum markers.

METHODS/DESIGN: This study is a randomized, double-blind, placebo-controlled clinical trial. A total of 80 patients (aged 60-85 years) will be recruited and allocated randomly to a treatment group and a placebo group in a 1:1 ratio and will then be administered YZASG or isodose placebo three times a day. The intervention course is 16 weeks, with an 18 months follow-up. The primary outcome is the Alzheimer's Disease Assessment Scale-Cognitive Subscale. Secondary outcome measures are the Mini-Mental State Examination, Montreal Cognitive Assessment, Pittsburgh Sleep Quality Index, serum concentrations of immunological factors and inflammatory cytokines, and fecal microbiota. Fecal microbiota will only be collected at the baseline and endpoint of the intervention.

DISCUSSION: The results of this trial will be conducive to assessing the safety and effectiveness on cognition of YZASG in intervening aMCI among the elderly and determining if it takes effect via the improvement of sleep quality, regulation of gut microbiota, and concentration of certain serum markers.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT03601000 . Registered on 26 July 2018.

RevDate: 2019-08-20

Vital M, Rud T, Rath S, et al (2019)

Diversity of Bacteria Exhibiting Bile Acid-inducible 7α-dehydroxylation Genes in the Human Gut.

Computational and structural biotechnology journal, 17:1016-1019 pii:S2001-0370(19)30223-5.

The secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA), formed by gut microbiota from primary bile acids via a multi-step 7α-dehydroxylation reaction, have wide-ranging effects on host metabolism and play an important role in health and disease. A few 7α-dehydroxylating strains have been isolated, where bile acid-inducible (bai) genes were organized in a gene cluster and encoded major enzymes involved. However, only little is known on diversity and abundance of intestinal bacteria catalysing DCA/LCA formation in the human gut in situ. In this study, we took the opportunity to screen metagenome-assembled genomes (MAGs) from sequence data of stool samples provided by two recent studies along with newly available gut-derived isolates for the presence of the bai gene cluster. We revealed in total 765 and 620 MAGs encoding the potential to form DCA/LCA that grouped into 21 and 26 metagenomic species, respectively. The majority of MAGs (92.4 and 90.3%) were associated with a Ruminococcaceae clade that still lacks an isolate, whereas less MAGs belonged to Lachnospiraceae along with eight new isolates (n total = 11) that contained the bai genes. Only a few MAGs were linked to Peptostreptococcaceae. Signatures for horizontal transfer of bai genes were observed. This study gives a comprehensive overview of the diversity of bai-exhibiting bacteria in the human gut highlighting the application of metagenomics to unravel potential functions hidden from current isolates. Eventually, isolates of the identified main MAG clade are required in order to prove their capability of 7α-dehydroxylating primary bile acids.

RevDate: 2019-08-20

Jiang X, Cui X, Xu H, et al (2019)

Whole Genome Sequencing of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli Isolated From a Wastewater Treatment Plant in China.

Frontiers in microbiology, 10:1797.

Background and Objectives: Wastewater treatment plants (WWTPs) are one of the major reservoirs for antimicrobial resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in the environment. Thus, the investigation on ARB and ARGs from WWTPs has attracted increasing attention in recent years. In order to uncover the resistome in a WWTP treating effluents from a pharmaceutical industry in China, the extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains were isolated and their whole genome sequences were obtained and analyzed. Moreover, metagenomic sequencing was applied to give a comprehensive view of antibiotic resistance in this WWTP.

Methods: 18 ESBL-producing E. coli strains were isolated from a WWTP located in Taizhou, China on April, 2017. All strains were sequenced using Illumina HiSeq 2000 sequencer. The whole genome sequences were assembled using SPAdes software and annotated with RAST server. Sequence types (STs), plasmids, ARGs and virulence genes were predicted from the genomes using MLST, Plasmid Finder, ResFinder and Virulence Finder, respectively. Metagenomic DNA of the same sample was extracted and sequenced using Illumina Hiseq X Ten platform. Metagenomic sequences were assembled using SOAPdenovo software.

Results: All 18 ESBL-producing E. coli strains were resistant to ampicillin, cefazolin, and ceftriaxone. Analysis of their genomes revealed that all strains carried beta-lactamase encoding genes and the most prevalent type was blaCTX-M . Various virulence genes and ARGs confronting resistance to other types of antimicrobial agents were also predicted. Further investigation on the metagenomics data indicated 11 ARGs with high amino acid identities to the known ARGs. Five of these ARGs, aadA1, aac(6')-lb-cr, flo(R), sul2 and sul1, were also present in the genomes of the ESBL-producing E. coli isolated from the same sample.

Conclusion: Our study revealed the resistome of a pharmaceutical WWTP by both culture-dependent and metegenomic methods. The existence of ESBL-producing E. coli strains, indicating that pharmaceutical WWTP can play a significant role in the emergence of ARB. The occurrence of ARGs annotated from the metagenomic data suggests that pharmaceutical WWTP can play a significant role in the emergence of ARGs. Our findings highlight the need for strengthening the active surveillance of ARB and ARGs from pharmaceutical industry.

RevDate: 2019-08-20

Kumar J, Sharma N, Kaushal G, et al (2019)

Metagenomic Insights Into the Taxonomic and Functional Features of Kinema, a Traditional Fermented Soybean Product of Sikkim Himalaya.

Frontiers in microbiology, 10:1744.

Kinema is an ethnic, naturally fermented soybean product consumed in the Sikkim Himalayan region of India. In the present study, the whole metagenome sequencing approach was adopted to examine the microbial diversity and related functional potential of Kinema, consumed in different seasons. Firmicutes was the abundant phylum in Kinema, ranging from 82.31 to 93.99% in different seasons, followed by Actinobacteria and Proteobacteria. At the species level, the prevalent microorganisms were Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, Corynebacterium glutamicum, Bacillus pumilus, and Lactococcus lactis. The abundance of microbial species varied significantly in different seasons. Further, the genomic presence of some undesirable microbes like Bacillus cereus, Proteus mirabilis, Staphylococcus aureus, Proteus penneri, Enterococcus faecalis, and Staphylococcus saprophyticus, were also detected in the specific season. The metagenomic analysis also revealed the existence of bacteriophages belonging to the family Siphoviridae, Myoviridae, and Podoviridae. Examination of the metabolic potential of the Kinema metagenome depicted information about the biocatalysts, presumably involved in the transformation of protein and carbohydrate polymers into bioactive molecules of health-beneficial effects. The genomic resource of several desirable enzymes was identified, such as β-galactosidase, β-glucosidase, β-xylosidase, and glutamate decarboxylase, etc. The catalytic function of a novel glutamate decarboxylase gene was validated for the biosynthesis of γ-aminobutyric acid (GABA). The results of the present study highlight the microbial and genomic resources associated with Kinema, and its importance in functional food industry.

RevDate: 2019-08-20

Kjeldsen KU, Schreiber L, Thorup CA, et al (2019)

On the evolution and physiology of cable bacteria.

Proceedings of the National Academy of Sciences of the United States of America pii:1903514116 [Epub ahead of print].

Cable bacteria of the family Desulfobulbaceae form centimeter-long filaments comprising thousands of cells. They occur worldwide in the surface of aquatic sediments, where they connect sulfide oxidation with oxygen or nitrate reduction via long-distance electron transport. In the absence of pure cultures, we used single-filament genomics and metagenomics to retrieve draft genomes of 3 marine Candidatus Electrothrix and 1 freshwater Ca. Electronema species. These genomes contain >50% unknown genes but still share their core genomic makeup with sulfate-reducing and sulfur-disproportionating Desulfobulbaceae, with few core genes lost and 212 unique genes (from 197 gene families) conserved among cable bacteria. Last common ancestor analysis indicates gene divergence and lateral gene transfer as equally important origins of these unique genes. With support from metaproteomics of a Ca. Electronema enrichment, the genomes suggest that cable bacteria oxidize sulfide by reversing the canonical sulfate reduction pathway and fix CO2 using the Wood-Ljungdahl pathway. Cable bacteria show limited organotrophic potential, may assimilate smaller organic acids and alcohols, fix N2, and synthesize polyphosphates and polyglucose as storage compounds; several of these traits were confirmed by cell-level experimental analyses. We propose a model for electron flow from sulfide to oxygen that involves periplasmic cytochromes, yet-unidentified conductive periplasmic fibers, and periplasmic oxygen reduction. This model proposes that an active cable bacterium gains energy in the anodic, sulfide-oxidizing cells, whereas cells in the oxic zone flare off electrons through intense cathodic oxygen respiration without energy conservation; this peculiar form of multicellularity seems unparalleled in the microbial world.

RevDate: 2019-08-20

Li H, Li H, Wang J, et al (2019)

The altered gut virome community in rhesus monkeys is correlated with the gut bacterial microbiome and associated metabolites.

Virology journal, 16(1):105 pii:10.1186/s12985-019-1211-z.

BACKGROUND: The gut microbiome is closely associated with the health of the host; although the interaction between the bacterial microbiome and the whole virome has rarely been studied, it is likely of medical importance. Examination of the interactions between the gut bacterial microbiome and virome of rhesus monkey would significantly contribute to revealing the gut microbiome composition.

METHODS: Here, we conducted a metagenomic analysis of the gut microbiome of rhesus monkeys in a longitudinal cohort treated with an antibiotic cocktail, and we documented the interactions between the bacterial microbiome and virome. The depletion of viral populations was confirmed at the species level by real-time PCR. We also detected changes in the gut metabolome by GC-MS and LC-MS.

RESULTS: A majority of bacteria were depleted after treatment with antibiotics, and the Shannon diversity index decreased from 2.95 to 0.22. Furthermore, the abundance-based coverage estimator (ACE) decreased from 104.47 to 33.84, and the abundance of eukaryotic viruses also changed substantially. In the annotation, 6 families of DNA viruses and 1 bacteriophage family were present in the normal monkeys but absent after gut bacterial microbiome depletion. Intriguingly, we discovered that changes in the gut bacterial microbiome composition may promote changes in the gut virome composition, and tryptophan, arginine, and quinone may play roles in the interaction between the bacterial microbiome and virome.

CONCLUSION: Our results indicated that the clearly altered composition of the virome was correlated with depletion in the bacterial community and that metabolites produced by bacteria possibly play important roles in the interaction.

RevDate: 2019-08-20

Shean RC, AL Greninger (2019)

One future of clinical metagenomic sequencing for infectious diseases.

Expert review of molecular diagnostics [Epub ahead of print].

RevDate: 2019-08-20

Hernández-Beeftink T, Guillen-Guio B, Villar J, et al (2019)

Genomics and the Acute Respiratory Distress Syndrome: Current and Future Directions.

International journal of molecular sciences, 20(16): pii:ijms20164004.

The excessive hospital mortality associated with acute respiratory distress syndrome (ARDS) in adults mandates an urgent need for developing new therapies and tools for the early risk assessment of these patients. ARDS is a heterogeneous syndrome with multiple different pathogenetic processes contributing differently in different patients depending on clinical as well as genetic factors. Identifying genetic-based biomarkers holds the promise for establishing effective predictive and prognostic stratification methods and for targeting new therapies to improve ARDS outcomes. Here we provide an updated review of the available evidence supporting the presence of genetic factors that are predictive of ARDS development and of fatal outcomes in adult critically ill patients and that have been identified by applying different genomic and genetic approaches. We also introduce other incipient genomics approximations, such as admixture mapping, metagenomics and genome sequencing, among others, that will allow to boost this knowledge and likely reveal new genetic predictors of ARDS susceptibility and prognosis among critically ill patients.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Ghani MI, Ali A, Atif MJ, et al (2019)

Changes in the Soil Microbiome in Eggplant Monoculture Revealed by High-Throughput Illumina MiSeq Sequencing as Influenced by Raw Garlic Stalk Amendment.

International journal of molecular sciences, 20(9): pii:ijms20092125.

The incorporation of plant residues into soil can be considered a keystone sustainability factor in improving soil structure function. However, the effects of plant residue addition on the soil microbial communities involved in biochemical cycles and abiotic stress phenomena are poorly understood. In this study, experiments were conducted to evaluate the role of raw garlic stalk (RGS) amendment in avoiding monoculture-related production constraints by studying the changes in soil chemical properties and microbial community structures. RGS was applied in four different doses, namely the control (RGS0), 1% (RGS1), 3% (RGS2), and 5% (RGS3) per 100 g of soil. The RGS amendment significantly increased soil electrical conductivity (EC), N, P, K, and enzyme activity. The soil pH significantly decreased with RGS application. High-throughput Illumina MiSeq sequencing revealed significant alterations in bacterial community structures in response to RGS application. Among the 23 major taxa detected, Anaerolineaceae, Acidobacteria, and Cyanobacteria exhibited an increased abundance level. RGS2 increased some bacteria reported to be beneficial including Acidobacteria, Bacillus, and Planctomyces (by 42%, 64%, and 1% respectively). Furthermore, internal transcribed spacer (ITS) fungal regions revealed significant diversity among the different treatments, with taxa such as Chaetomium (56.2%), Acremonium (4.3%), Fusarium (4%), Aspergillus (3.4%), Sordariomycetes (3%), and Plectosphaerellaceae (2%) showing much abundance. Interestingly, Coprinellus (14%) was observed only in RGS-amended soil. RGS treatments effectively altered soil fungal community structures and reduced certain known pathogenic fungal genera, i.e., Fusarium and Acremonium. The results of the present study suggest that RGS amendment potentially affects the microbial community structures that probably affect the physiological and morphological attributes of eggplant under a plastic greenhouse vegetable cultivation system (PGVC) in monoculture.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Chibani CM, Farr A, Klama S, et al (2019)

Classifying the Unclassified: A Phage Classification Method.

Viruses, 11(2): pii:v11020195.

This work reports the method ClassiPhage to classify phage genomes using sequence derived taxonomic features. ClassiPhage uses a set of phage specific Hidden Markov Models (HMMs) generated from clusters of related proteins. The method was validated on all publicly available genomes of phages that are known to infect Vibrionaceae. The phages belong to the well-described phage families of Myoviridae, Podoviridae, Siphoviridae, and Inoviridae. The achieved classification is consistent with the assignments of the International Committee on Taxonomy of Viruses (ICTV), all tested phages were assigned to the corresponding group of the ICTV-database. In addition, 44 out of 58 genomes of Vibrio phages not yet classified could be assigned to a phage family. The remaining 14 genomes may represent phages of new families or subfamilies. Comparative genomics indicates that the ability of the approach to identify and classify phages is correlated to the conserved genomic organization. ClassiPhage classifies phages exclusively based on genome sequence data and can be applied on distinct phage genomes as well as on prophage regions within host genomes. Possible applications include (a) classifying phages from assembled metagenomes; and (b) the identification and classification of integrated prophages and the splitting of phage families into subfamilies.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Tan S, Cheung S, Ho TY, et al (2019)

Metatranscriptomics of the bacterial community in response to atmospheric deposition in the Western North Pacific Ocean.

Marine genomics, 45:57-63.

Atmospheric deposition represents a major vector of both macro- and micro-nutrients to the oligotrophic open oceans, potentially imposing a profound impact on the functioning of the microbial community. Whereas bacterial responses to atmospheric deposition are being studied at the community level, corresponding functional changes are essentially unknown. Here we conducted a microcosm experiment coupled with metatranscriptomic analyses to elucidate taxonomic and functional profiles of the bacterial community in response to East Asian aerosols in the Western North Pacific Ocean (WNPO). While the abundance of heterotrophic bacteria showed a minor change, cyanobacterial cell count number decreased dramatically, with Prochlorococcus and Synechococcus counts reduced by 83.2% and 21.5% in the aerosol treatment in relation to the control. Expression of transcripts related with Prochlorococcus, Synechococcus, Trichodesmium and Crocosphaera both were lower in the treatment (5.7%, 2.3%, 0.5% and 0.02%, respectively) than in the control (18.6%, 2.7%, 9.8% and 0.14%, respectively). Aerosol addition led to an increase in transcripts involved in iron metabolism (tonB, feoB, irr, exbB), indicating Fe limitation. Heavy metal toxicity was evidenced by an elevated expression of resistance genes, such as czcC, czcB, czcA and a probable Co/Zn/Cd efflux protein, and a range of genes functioning against oxidative stress. Our findings provide insights into an inhibitory effect of high-flux East Asian aerosols on cyanobacteria in the WNPO likely due to Fe scavenging and heavy metal toxicity.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Ribeiro ÂM, Canchaya CA, Penaloza F, et al (2019)

Population genomic footprints of environmental pollution pressure in natural populations of the Mediterranean mussel.

Marine genomics, 45:11-15.

Bivalve molluscs of the genus Mytilus are considered a model organism in ecotoxicology and are known to be well adapted to marine ecosystems affected by multiple anthropogenic factors, including pollution. In order to assess whether pollution interferes with the reproductive success of Mytilus and affects the diversity within and between populations, we sequenced the transcriptomes of 72 individuals from 9 populations of Mytilus galloprovincialis collected along a ca. 130-km north-south transect on the Western coast of the Iberian Peninsula. We found that polluted areas are acting as a barrier to gene flow, potentially because of the detrimental effect of anthropogenic chemicals on larvae carried from more pristine environments. Furthermore, we observed an increase in genetic diversity in populations from polluted site, which could be indicative of higher mutagenicity driven by the environment. We propose that a microevolutionary perspective is essential for a full characterization of human activities on the dispersal of M. galloprovincialis and that it should be incorporated into management, and conservation plans and policies in the context of the effects of pollution on populations.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Foster ZSL, Chamberlain S, NJ Grünwald (2018)

Taxa: An R package implementing data standards and methods for taxonomic data.

F1000Research, 7:272.

The taxa R package provides a set of tools for defining and manipulating taxonomic data. The recent and widespread application of DNA sequencing to community composition studies is making large data sets with taxonomic information commonplace. However, compared to typical tabular data, this information is encoded in many different ways and the hierarchical nature of taxonomic classifications makes it difficult to work with. There are many R packages that use taxonomic data to varying degrees but there is currently no cross-package standard for how this information is encoded and manipulated. We developed the R package taxa to provide a robust and flexible solution to storing and manipulating taxonomic data in R and any application-specific information associated with it. Taxa provides parsers that can read common sources of taxonomic information (taxon IDs, sequence IDs, taxon names, and classifications) from nearly any format while preserving associated data. Once parsed, the taxonomic data and any associated data can be manipulated using a cohesive set of functions modeled after the popular R package dplyr. These functions take into account the hierarchical nature of taxa and can modify the taxonomy or associated data in such a way that both are kept in sync. Taxa is currently being used by the metacoder and taxize packages, which provide broadly useful functionality that we hope will speed adoption by users and developers.

RevDate: 2019-08-20
CmpDate: 2019-08-20

Xu W, You Y, Wang Z, et al (2018)

Dibutyl phthalate alters the metabolic pathways of microbes in black soils.

Scientific reports, 8(1):2605.

Dibutyl phthalate (DBP) is well known as a high-priority pollutant. This study explored the impacts of DBP on the metabolic pathways of microbes in black soils in the short term (20 days). The results showed that the microbial communities were changed in black soils with DBP. In nitrogen cycling, the abundances of the genes were elevated by DBP. DBP contamination facilitated 3'-phosphoadenosine-5'-phosphosulfate (PAPS) formation, and the gene flux of sulfate metabolism was increased. The total abundances of ABC transporters and the gene abundances of the monosaccharide-transporting ATPases MalK and MsmK were increased by DBP. The total abundance of two-component system (TCS) genes and the gene abundances of malate dehydrogenase, histidine kinase and citryl-CoA lyase were increased after DBP contamination. The total abundance of phosphotransferase system (PTS) genes and the gene abundances of phosphotransferase, Crr and BglF were raised by DBP. The increased gene abundances of ABC transporters, TCS and PTS could be the reasons for the acceleration of nitrogen, carbon and sulfate metabolism. The degrading-genes of DBP were increased markedly in soil exposed to DBP. In summary, DBP contamination altered the microbial community and enhanced the gene abundances of the carbon, nitrogen and sulfur metabolism in black soils in the short term.

RevDate: 2019-08-19

Mougeot JC, Stevens CB, Morton DS, et al (2019)

Oral Microbiome and Cancer Therapy-Induced Oral Mucositis.

Journal of the National Cancer Institute. Monographs, 2019(53):.

Characterization of the role of oral microbiome in cancer therapy-induced oral mucositis (CTOM) is critical in preventing the clinically deleterious effects on patients' health that are associated with CTOM. Funding initiatives related to the National Institutes of Health human microbiome project have resulted in groundbreaking advancements in biology and medicine during the last decade. These advancements have shown that a human being is in fact a superorganism made of human cells and associated symbiotic or commensal microbiota. In this review, we describe the state of science as it relates to fundamental knowledge on oral microbiome and its role in CTOM. We also discuss how state-of-the-art technologies and systems biology tools may be used to help tackle the difficult challenges ahead to develop effective treatments or preventive therapies for oral mucositis. We make a clear distinction between disease processes pertaining to the oral microbiome, which includes opportunistic pathogens that may be defined as pathobionts, and those infectious disease processes initiated by exogenous pathogens. We also explored the extent to which knowledge from the gastrointestinal tract in disease and intestinal mucositis could help us better understand CTOM pathobiology. Finally, we propose a model in which the oral microbiome participates in the current five-step CTOM pathobiology model. With the advent of more sophisticated metagenomics technologies and methods of analysis, much hope lies ahead to implement an effective holistic approach to treat cancer patients affected by CTOM.

RevDate: 2019-08-19

Pattabiraman S, T Warnow (2019)

Profile Hidden Markov Models are Not Identifiable.

IEEE/ACM transactions on computational biology and bioinformatics [Epub ahead of print].

Profile Hidden Markov Models (HMMs) are graphical models that can be used to produce finite length sequences from a distribution. They have multiple applications, including protein structure and function prediction, classifications of novel proteins into existing protein families and superfamilies, metagenomics, and multiple sequence alignment. The standard use of profile HMMs in bioinformatics has two steps: first a profile HMM is built for a collection of molecular sequences (which may not be in a multiple sequence alignment), and then the profile HMM is used in some subsequent analysis of new molecular sequences. The construction of the profile thus is itself a statistical estimation problem, since any given set of sequences might potentially fit more than one model well. Hence a basic question about profile HMMs is whether they are statistically identifiable, which means that no two profile HMMs can produce the same distribution on finite length sequences. Indeed, statistical identifiability is a fundamental aspect of any statistical model, and yet it is not known whether profile HMMs are statistically identifiable. In this paper, we report on preliminary results towards characterizing the statistical identifiability of profile HMMs in one of the standard forms used in bioinformatics.

RevDate: 2019-08-19

Kanehisa M, Y Sato (2019)

KEGG Mapper for inferring cellular functions from protein sequences.

Protein science : a publication of the Protein Society [Epub ahead of print].

KEGG is a reference knowledge base for biological interpretation of large-scale molecular datasets, such as genome and metagenome sequences. It accumulates experimental knowledge about high-level functions of the cell and the organism represented in terms of KEGG molecular networks, including KEGG pathway maps, BRITE hierarchies, and KEGG modules. By the process called KEGG mapping, a set of protein coding genes in the genome, for example, can be converted to KEGG molecular networks enabling interpretation of cellular functions and other high-level features. Here we report a new version of KEGG Mapper, a suite of KEGG mapping tools available at the KEGG website (https://www.kegg.jp/ or https://www.genome.jp/kegg/), together with the KOALA family tools for automatic assignment of KO (KEGG Orthology) identifiers used in the mapping.

RevDate: 2019-08-19

Casaburi G, Duar RM, Vance DP, et al (2019)

Early-life gut microbiome modulation reduces the abundance of antibiotic-resistant bacteria.

Antimicrobial resistance and infection control, 8:131 pii:583.

Background: Antibiotic-resistant (AR) bacteria are a global threat. AR bacteria can be acquired in early life and have long-term sequelae. Limiting the spread of antibiotic resistance without triggering the development of additional resistance mechanisms is of immense clinical value. Here, we show how the infant gut microbiome can be modified, resulting in a significant reduction of AR genes (ARGs) and the potentially pathogenic bacteria that harbor them.

Methods: The gut microbiome was characterized using shotgun metagenomics of fecal samples from two groups of healthy, term breastfed infants. One group was fed B. infantis EVC001 in addition to receiving lactation support (n = 29, EVC001-fed), while the other received lactation support alone (n = 31, controls). Coliforms were isolated from fecal samples and genome sequenced, as well as tested for minimal inhibitory concentrations against clinically relevant antibiotics.

Results: Infants fed B. infantis EVC001 exhibited a change to the gut microbiome, resulting in a 90% lower level of ARGs compared to controls. ARGs that differed significantly between groups were predicted to confer resistance to beta lactams, fluoroquinolones, or multiple drug classes, the majority of which belonged to Escherichia, Clostridium, and Staphylococcus. Minimal inhibitory concentration assays confirmed the resistance phenotypes among isolates with these genes. Notably, we found extended-spectrum beta lactamases among healthy, vaginally delivered breastfed infants who had never been exposed to antibiotics.

Conclusions: Colonization of the gut of breastfed infants by a single strain of B. longum subsp. infantis had a profound impact on the fecal metagenome, including a reduction in ARGs. This highlights the importance of developing novel approaches to limit the spread of these genes among clinically relevant bacteria. Future studies are needed to determine whether colonization with B. infantis EVC001 decreases the incidence of AR infections in breastfed infants.

Trial registration: This clinical trial was registered at ClinicalTrials.gov, NCT02457338.

RevDate: 2019-08-19

Wong YKE, Lam KW, Ho KY, et al (2019)

The applications of Big Data in molecular diagnostics.

Expert review of molecular diagnostics [Epub ahead of print].

Introduction: Big Data technologies instilled an informational perspective to our understanding of the world. However, fundamental issues such as the management and storage of data can create privacy concerns. Heterogeneous types of data pose challenges in reproducibility and standardization. It is now an opportunity for us to help the healthcare professionals, educators, and policy-makers understand the impact of Big Data, and steer the development roadmap to positively impact the molecular diagnostic industry. Area covered: In this review, we discuss the latest trends in applying Big Data to several key areas of molecular diagnostics: metagenomics, Mendelian disease screening, personalised medicine, and metabolomics. The limitations of utilising bioinformatics and Big Data analytic tools are also summarised. We further propose an action plan on how to prepare a new generation of healthcare professionals to step into the age of Big Data through a tailor-made bioinformatics training program. Expert opinion: In order to cope with the development of these powerful technologies, issues of ethics, regulations and data format standardization are urgently needed. Besides, a long-term planning to train medical scientists, pathologists and specialists on bioinformatics are necessary. It is an appropriate time to review all these issues before implementing these tests for patients' diagnosis, prognosis and treatment efficacy.

RevDate: 2019-08-18

Seitzman GD, Hinterwirth A, Zhong L, et al (2019)

Metagenomic Deep Sequencing for the Diagnosis of Corneal and External Disease Infections.

Ophthalmology pii:S0161-6420(19)30831-0 [Epub ahead of print].

RevDate: 2019-08-17

Piotrowski Y, Berg K, Klebl DP, et al (2019)

Characterization of an intertidal zone metagenome oligoribonuclease and the role of the intermolecular disulfide bond for homodimer formation and nuclease activity.

FEBS open bio [Epub ahead of print].

The gene encoding MG Orn has been identified from a metagenomic library created from the intertidal zone in Svalbard and encodes a protein of 184 amino-acid residues. The mg orn gene has been cloned, recombinantly expressed in Escherichia coli and purified to homogeneity. Biochemical characterization of the enzyme showed that it efficiently degrades short RNA oligonucleotide substrates of 2mer to 10mer of length and has an absolute requirement for divalent cations for optimal activity. The enzyme is more heat labile than its counterpart from Escherichia coli and exists as a homodimer in solution. The crystal structure of the enzyme has been determined to a resolution of 3.15 Å, indicating an important role of a disulfide bridge for the homodimer formation, and as such for the function of MG Orn. Substitution of the Cys110 residue with either Gly or Ala hampered the dimer formation and severely affected the enzyme's ability to act on RNA. A conserved loop containing His128-Tyr129-Arg130 in the neighboring monomer is probably involved in efficient binding and processing of longer RNA substrates than diribonucleotides.

RevDate: 2019-08-17

Carabeo-Pérez A, Guerra-Rivera G, Ramos-Leal M, et al (2019)

Metagenomic approaches: effective tools for monitoring the structure and functionality of microbiomes in anaerobic digestion systems.

Applied microbiology and biotechnology pii:10.1007/s00253-019-10052-5 [Epub ahead of print].

Microbial metagenome analysis has proven its usefulness to investigate the microbiomes present in technical engineered ecosystems such as anaerobic digestion systems. The analysis of the total microbial genomic DNA allows the detailed determination of both the microbial community structure and its functionality. In addition, it enables to study the response of the microbiome to alterations in technical process parameters. Strategies of functional microbial networks to face abiotic stressors, e.g., resistance, resilience, and reorganization, can be evaluated with respect to overall process optimization. The objective of this paper is to review the main metagenomic tools used for effective studies on anaerobic digestion systems in monitoring the dynamic of the microbiomes, as well as the factors that have been identified so far as limiting the metagenomic studies in this ecosystems.

RevDate: 2019-08-17

In 't Zandt MH, Kip N, Frank J, et al (2019)

High abundance of Methanobacteriales and Syntrophobacterales may help to prevent corrosion of metal sheet piles.

Applied and environmental microbiology pii:AEM.01369-19 [Epub ahead of print].

Iron sheet piles are widely used in flood protection, dike construction and river bank reinforcement. Their corrosion leads to gradual deterioration and often makes replacement necessary. Natural deposit layers on these sheet piles can prevent degradation and significantly increase their lifespan. However, little is known about the mechanisms of natural protective layer formation. Here, we studied the microbial diversity of corrosion-protective deposit layers on iron sheet piles at the Gouderak pumping station in Zuid-Holland, the Netherlands. Deposit layers, surrounding sediment and top sediment samples were analyzed for soil physicochemical parameters, microbial diversity and metabolic potential. Methanogens appeared to be enriched 18-fold in the deposit layers. After sequencing, metagenome assembly and binning, we obtained four near-complete draft genomes of microorganisms (Methanobacteriales, two Coriobacteriales and Syntrophobacterales) that were highly enriched in the deposit layers, strongly indicating a potential role in corrosion protection. Coriobacteriales and Syntrophobacterales could be part of a microbial foodweb degrading organic matter to supply methanogenic substrates. Methane-producing Methanobacteriales could metabolize iron which may initially lead to mild corrosion but potentially stimulates the formation of a carbonate-rich protective deposit layer in the long term. In addition, Methanobacteriales and Coriobacteriales have the potential to interact with metal surfaces via direct interspecies or extracellular electron transfer. In conclusion, our study provides valuable insights into microbial populations involved in iron corrosion protection and potentially enables the development of novel strategies for in-situ screening of iron sheet piles in order to reduce risks and develop more sustainable replacement practices.Importance Iron sheet piles are widely used to reinforce dikes and river banks. Damage due to iron corrosion poses a significant safety risk and has major economical impacts. Different groups of microorganisms are known to either stimulate or inhibit the corrosion process. Recently, natural corrosion-protective deposit layers were found on sheet piles. Analyses of the microbial composition indicated a potential role for methane-producing archaea. However, the full metabolic potential of the microbial communities within these protective layers has not been determined. The significance of this work lies in the reconstruction of the microbial food web of natural corrosion-protective layers isolated from non-corroding metal sheet piles. With this work, we provide insights into the microbiological mechanisms that potentially promote corrosion protection in freshwater ecosystems. Our findings could support the development of screening protocols to assess the integrity of iron sheet piles to decide whether replacement is required.

RevDate: 2019-08-17

Ryan FJ (2019)

Application of machine learning techniques for creating urban microbial fingerprints.

Biology direct, 14(1):13 pii:10.1186/s13062-019-0245-x.

BACKGROUND: Research has found that human associated microbial communities play a role in homeostasis and the disruption of these communities may be important in an array of medical conditions. However outside of the human body many of these communities remain poorly studied. The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) International Consortium is characterizing the microbiomes of urban environments with the aim to improve design of mass transit systems. As part of the CAMDA 2018 MetaSUB Forensics Challenge 311 city microbiome samples were provided to create urban microbial fingerprints, as well as a further 3 mystery datasets for validation.

RESULTS: MetaSUB samples were clustered using t-SNE in an unsupervised fashion to almost discrete groups, which upon inspection represented city of origin. Based on this clustering, geographically close metropolitan areas appear to display similar microbial profiles such as those of Auckland and Hamilton. Mystery unlabeled samples were provided part of the challenge. A random forest classifier built on the initial dataset of 311 samples was capable of correctly classifying 83.3% of the mystery samples to their city of origin. Random Forest analyses also identified features with the highest discriminatory power, ranking bacterial species such as Campylobacter jejuni and Staphylococcus argenteus as highly predictive of city of origin. The surface from which the sample was collected displayed little detectable impact on the microbial profiles in the data generated here. The proportion of reads classified per sample varied greatly and so de-novo assembly was applied to recover genomic fragments representing organisms not captured in reference databases.

CONCLUSIONS: Current methods can differentiate urban microbiome profiles from each other with relative ease. De-novo assembly indicated that the MetaSUB metagenomic data contains adequate depth to recover metagenomic assembled genomes and that current databases are not sufficient to fully characterize urban microbiomes. Profiles found here indicate there may be a relationship between geographical distance between areas and the urban microbiome composition although this will need further research. The impact of these different profiles on public health is currently unknown but the MetaSUB consortium is uniquely suited to evaluate these and provide a roadmap for the inclusion of urban microbiome information for city planning and public health policy.

REVIEWERS: This article was reviewed by Dimitar Vassilev, Eran Elhaik and Chengsheng Zhu.

RevDate: 2019-08-17

Shami A, Al-Mijalli S, Pongchaikul P, et al (2019)

The prevalence of the culturable human skin aerobic bacteria in Riyadh, Saudi Arabia.

BMC microbiology, 19(1):189 pii:10.1186/s12866-019-1569-5.

BACKGROUND: Human skin is an appropriate environment for the growth of different types of microbes that may inhabit the skin as commensal flora. This study aims at identifying the diversity of skin microbiota in healthy Saudi population. In this study, 80 Saudi subjects of both males and females, from different habitat, and different ages (elderly and young), were recruited to determine the aerobic bacterial flora from their three skin sites; hand, scalp and foot. A single colony obtained from aerobic culture was identified using Biomérieux VITEK® 2 system. For those not being identified by VITEK® 2 system, the identification was conducted using 16 s rRNA sequence.

RESULTS: Thirty-three bacterial species were isolated from males, whilst 24 species were isolated from females. Micrococci are the predominant organisms, followed by Staphylococci, Pantoea species, and lastly Enterococcus faecium. Acinetobacter baumannii, Enterococcus faecalis, and Klebsiella pneumoniae were only found in elder subjects, while Pseudomonas aeruginosa was isolated from the young only. The number of bacterial isolates in the elders was higher that of the young. The average number of flora was larger in foot, then hand and lastly scalp.

CONCLUSION: Here we show the difference in the number of cultivable bacteria across age and gender that may result in the variety of local skin infection. This study paves the way to further investigation in the aspect of in-depth metagenomics analysis and host-pathogen interaction.

RevDate: 2019-08-19
CmpDate: 2019-08-19

Zeevi D, Korem T, Godneva A, et al (2019)

Structural variation in the gut microbiome associates with host health.

Nature, 568(7750):43-48.

Differences in the presence of even a few genes between otherwise identical bacterial strains may result in critical phenotypic differences. Here we systematically identify microbial genomic structural variants (SVs) and find them to be prevalent in the human gut microbiome across phyla and to replicate in different cohorts. SVs are enriched for CRISPR-associated and antibiotic-producing functions and depleted from housekeeping genes, suggesting that they have a role in microbial adaptation. We find multiple associations between SVs and host disease risk factors, many of which replicate in an independent cohort. Exploring genes that are clustered in the same SV, we uncover several possible mechanistic links between the microbiome and its host, including a region in Anaerostipes hadrus that encodes a composite inositol catabolism-butyrate biosynthesis pathway, the presence of which is associated with lower host metabolic disease risk. Overall, our results uncover a nascent layer of variability in the microbiome that is associated with microbial adaptation and host health.

RevDate: 2019-08-16

Ramayo-Caldas Y, Zingaretti L, Popova M, et al (2019)

Identification of rumen microbial biomarkers linked to methane emission in Holstein dairy cows.

Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie [Epub ahead of print].

Mitigation of greenhouse gas emissions is relevant for reducing the environmental impact of ruminant production. In this study, the rumen microbiome from Holstein cows was characterized through a combination of 16S rRNA gene and shotgun metagenomic sequencing. Methane production (CH4) and dry matter intake (DMI) were individually measured over 4-6 weeks to calculate the CH4 yield (CH4 y = CH4 /DMI) per cow. We implemented a combination of clustering, multivariate and mixed model analyses to identify a set of operational taxonomic unit (OTU) jointly associated with CH4 y and the structure of ruminal microbial communities. Three ruminotype clusters (R1, R2 and R3) were identified, and R2 was associated with higher CH4 y. The taxonomic composition on R2 had lower abundance of Succinivibrionaceae and Methanosphaera, and higher abundance of Ruminococcaceae, Christensenellaceae and Lachnospiraceae. Metagenomic data confirmed the lower abundance of Succinivibrionaceae and Methanosphaera in R2 and identified genera (Fibrobacter and unclassified Bacteroidales) not highlighted by metataxonomic analysis. In addition, the functional metagenomic analysis revealed that samples classified in cluster R2 were overrepresented by genes coding for KEGG modules associated with methanogenesis, including a significant relative abundance of the methyl-coenzyme M reductase enzyme. Based on the cluster assignment, we applied a sparse partial least-squares discriminant analysis at the taxonomic and functional levels. In addition, we implemented a sPLS regression model using the phenotypic variation of CH4 y. By combining these two approaches, we identified 86 discriminant bacterial OTUs, notably including families linked to CH4 emission such as Succinivibrionaceae, Ruminococcaceae, Christensenellaceae, Lachnospiraceae and Rikenellaceae. These selected OTUs explained 24% of the CH4 y phenotypic variance, whereas the host genome contribution was ~14%. In summary, we identified rumen microbial biomarkers associated with the methane production of dairy cows; these biomarkers could be used for targeted methane-reduction selection programmes in the dairy cattle industry provided they are heritable.

RevDate: 2019-08-16

Allen JM, Jaggers RM, Solden LM, et al (2019)

Dietary Oligosaccharides Attenuate Stress-Induced Disruptions in Immune Reactivity and Microbial B-Vitamin Metabolism.

Frontiers in immunology, 10:1774.

Background: Exposure to stressful stimuli dysregulates inflammatory processes and alters the gut microbiota. Prebiotics, including long-chain fermentable fibers and milk oligosaccharides, have the potential to limit inflammation through modulation of the gut microbiota. To determine whether prebiotics attenuate stress-induced inflammation and microbiota perturbations, mice were fed either a control diet or a diet supplemented with galactooligosaccharides, polydextrose and sialyllactose (GOS+PDX+SL) or sialyllactose (SL) for 2 weeks prior to and during a 6-day exposure to a social disruption stressor. Spleens were collected for immunoreactivity assays. Colon contents were examined for stressor- and diet- induced changes in the gut microbiome and metabolome through 16S rRNA gene sequencing, shotgun metagenomic sequencing and UPLC-MS/MS. Results: Stress increased circulating IL-6 and enhanced splenocyte immunoreactivity to an ex vivo LPS challenge. Diets containing GOS+PDX+SL or SL alone attenuated these responses. Stress exposure resulted in large changes to the gut metabolome, including robust shifts in amino acids, peptides, nucleotides/nucleosides, tryptophan metabolites, and B vitamins. Multiple B vitamins were inversely associated with IL-6 and were augmented in mice fed either GOS+PDX+SL or SL diets. Stressed mice exhibited distinct microbial communities with lower abundances of Lactobacillus spp. and higher abundances of Bacteroides spp. Diet supplementation with GOS+PDX+SL, but not SL alone, orthogonally altered the microbiome and enhanced the growth of Bifidobacterium spp. Metagenome-assembled genomes (MAGs) from mice fed the GOS+PDX+SL diet unveiled genes in a Bifidobacterium MAG for de novo B vitamin synthesis. B vitamers directly attenuated the stressor-induced exacerbation of cytokine production in LPS-stimulated splenocytes. Conclusions: Overall, these data indicate that colonic metabolites, including B vitamins, are responsive to psychosocial stress. Dietary prebiotics reestablish colonic B vitamins and limit stress-induced inflammation.

RevDate: 2019-08-16

Conteville LC, Oliveira-Ferreira J, ACP Vicente (2019)

Gut Microbiome Biomarkers and Functional Diversity Within an Amazonian Semi-Nomadic Hunter-Gatherer Group.

Frontiers in microbiology, 10:1743.

Human groups that still maintain traditional modes of subsistence (hunter-gatherers and rural agriculturalists) represent human groups non-impacted by urban-industrialized lifestyles, and therefore their gut microbiome provides the basis for understanding the human microbiome evolution and its association with human health and disease. The Yanomami is the largest semi-nomadic hunter-gatherer group of the Americas, exploring different niches of the Amazon rainforest in Brazil and Venezuela. Here, based on shotgun metagenomic data, we characterized the gut microbiome of the Yanomami from Brazil and compared taxonomically and functionally with the Yanomami from Venezuela, with other traditional groups from the Amazon and an urban-industrialized group. Taxonomic biomarkers were identified to each South American traditional group studied, including each Yanomami group. Broader levels of functional categories poorly discriminated the traditional and urban-industrialized groups, but the stratification of these categories revealed clear segregation of these groups. The Yanomami/Brazil gut microbiome presented unique functional features, such as a higher abundance of gene families involved in regulation/cell signaling, motility/chemotaxis, and virulence, contrasting with the gut microbiomes from the Yanomami/Venezuela and the other groups. Our study revealed biomarkers, and taxonomic and functional features that distinguished the gut microbiome of Yanomami/Brazil and Yanomami/Venezuela individuals, despite their shared lifestyle, culture, and genetic background. These differences may be a reflection of the environmental and seasonal diversity of the niches they explore. Overall, their microbiome profiles are shared with South American and African traditional groups, probably due to their lifestyle. The unique features identified within the Yanomami highlight the bias imposed by underrepresented sampling, and factors such as variations over space and time (seasonality) that impact, mainly, the hunter-gatherers.

RevDate: 2019-08-16

Abbondio M, Palomba A, Tanca A, et al (2019)

Fecal Metaproteomic Analysis Reveals Unique Changes of the Gut Microbiome Functions After Consumption of Sourdough Carasau Bread.

Frontiers in microbiology, 10:1733.

Sourdough-leavened bread (SB) is acknowledged for its great variety of valuable effects on consumer's metabolism and health, including a low glycemic index and a reduced content of the possible carcinogen acrylamide. Here, we aimed to investigate how these effects influence the gut microbiota composition and functions. Therefore, we subjected rats to a diet supplemented with SB, baker's yeast leavened bread (BB), or unsupplemented diet (chow), and, after 4 weeks of treatment, their gut microbiota was analyzed using a metaproteogenomic approach. As a result, diet supplementation with SB led to a reduction of specific members of the intestinal microbiota previously associated to low protein diets, namely Alistipes and Mucispirillum, or known as intestinal pathobionts, i.e., Mycoplasma. Concerning functions, asparaginases expressed by Bacteroides were observed as more abundant in SB-fed rats, leading to hypothesize that in their colonic microbiota the enzyme substrate, asparagine, was available in higher amounts than in BB- and chow-fed rats. Another group of protein families, expressed by Clostridium, was detected as more abundant in animal fed SB-supplemented diet. Of these, manganese catalase, small acid-soluble proteins (SASP), Ser/Thr kinase PrkA, and V-ATPase proteolipid subunit have been all reported to take part in Clostridium sporulation, strongly suggesting that the diet supplementation with SB might promote environmental conditions inducing metabolic dormancy of Clostridium spp. within the gut microbiota. In conclusion, our data describe the effects of SB consumption on the intestinal microbiota taxonomy and functions in rats. Moreover, our results suggest that a metaproteogenomic approach can provide evidence of the interplay between metabolites deriving from bread digestion and microbial metabolism.

RevDate: 2019-08-16

Chen J, Wu X, Zhu D, et al (2019)

Microbiota in Human Periodontal Abscess Revealed by 16S rDNA Sequencing.

Frontiers in microbiology, 10:1723.

Periodontal abscess is an oral infective disease caused by various kinds of bacteria. We aimed to characterize the microbiota composition of periodontal abscesses by metagenomic methods and compare it to that of the corresponding pocket and healthy gingival crevice to investigate the specific bacteria associated with this disease. Samples from abscess pus (AB), periodontal pocket coronally above the abscess (PO), and the gingival crevice of the periodontal healthy tooth were obtained from 20 periodontal abscess patients. Furthermore, healthy gingival crevice samples were obtained from 25 healthy individuals. Bacterial DNA was extracted and 16S rRNA gene fragments were sequenced to characterize the microbiota and determine taxonomic classification. The beta-diversity analysis results showed that the AB and PO groups had similar compositions. Porphyromonas gingivalis, Prevotella intermedia, and other Prevotella spp. were the predominant bacteria of human periodontal abscesses. The abundances of Filifactor alocis and Atopobium rimae were significantly higher in periodontal abscesses than in the periodontal pocket, suggesting their association with periodontal abscess formation. In conclusion, we characterized the microbiota in periodontal abscess and identified some species that are positively associated with this disease. This provides a better understanding of the components of periodontal abscesses, which will help facilitate the development of antibiotic therapy strategies.

RevDate: 2019-08-16

de Chaves MG, Silva GGZ, Rossetto R, et al (2019)

Acidobacteria Subgroups and Their Metabolic Potential for Carbon Degradation in Sugarcane Soil Amended With Vinasse and Nitrogen Fertilizers.

Frontiers in microbiology, 10:1680.

Acidobacteria is a predominant bacterial phylum in tropical agricultural soils, including sugarcane cultivated soils. The increased need for fertilizers due to the expansion of sugarcane production is a threat to the ability of the soil to maintain its potential for self-regulation in the long term, in witch carbon degradation has essential role. In this study, a culture-independent approach based on high-throughput DNA sequencing and microarray technology was used to perform taxonomic and functional profiling of the Acidobacteria community in a tropical soil under sugarcane (Saccharum spp.) that was supplemented with nitrogen (N) combined with vinasse. These analyses were conducted to identify the subgroup-level responses to chemical changes and the carbon (C) degradation potential of the different Acidobacteria subgroups. Eighteen Acidobacteria subgroups from a total of 26 phylogenetically distinct subgroups were detected based on high-throughput DNA sequencing, and 16 gene families associated with C degradation were quantified using Acidobacteria-derived DNA microarray probes. The subgroups Gp13 and Gp18 presented the most positive correlations with the gene families associated with C degradation, especially those involved in hemicellulose degradation. However, both subgroups presented low abundance in the treatment containing vinasse. In turn, the Gp4 subgroup was the most abundant in the treatment that received vinasse, but did not present positive correlations with the gene families for C degradation analyzed in this study. The metabolic potential for C degradation of the different Acidobacteria subgroups in sugarcane soil amended with N and vinasse can be driven in part through the increase in soil nutrient availability, especially calcium (Ca), magnesium (Mg), potassium (K), aluminum (Al), boron (B) and zinc (Zn). This soil management practice reduces the abundance of Acidobacteria subgroups, including those potentially involved with C degradation in this agricultural soil.

RevDate: 2019-08-16

Khan I, Yasir M, Farman M, et al (2019)

Evaluation of gut bacterial community composition and antimicrobial resistome in pregnant and non-pregnant women from Saudi population.

Infection and drug resistance, 12:1749-1761 pii:200213.

Background: Gut microbiota (GM) has recently been described as a functional reservoir of antimicrobial resistant genes (ARGs). However, the ARG-carrying bacterial species in the human gut has been poorly studied. This study, for the first time, is reporting bacterial communities' composition and antimicrobial resistome in the stool samples of pregnant and non-pregnant (NP) Saudi females. Methods: Gut bacterial community composition was analyzed by 16S amplicon sequencing and culturomics. High throughput MALDI-TOF technique was used for identification of the isolates from stool samples and evaluated for resistance against 13 antibiotics using the agar dilution method. Clinically important ARGs were PCR amplified from genomic DNA of the stool samples using gene-specific primers. Results: 16S amplicon sequencing revealed that GM of pregnant and NP women were predominantly comprised of phyla Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. Bacterial diversity decreased in pregnant groups, whereas phylum Bacteroidetes declined significantly (p<0.05) in the first trimester. We noticed a relatively high abundance of butyrate-producing bacteria (eg, Faecalibacterium spp. and Eubacterium spp.) in the gut of pregnant women, whereas Prevotella copri was found at significantly (p<0.01) higher abundance in NP women. Moreover, about 14,694 isolates were identified and classified into 132 distinct species. The majority of the species belonged to phyla Firmicutes and Proteobacteria. About 8,125 isolates exhibited resistance against antibiotics. Out of 73 resistant-species, Enterococcus was the most diverse genus and Escherichia coli was the highly prevalent bacterium. The majority of the isolates were resistant to antibiotics; trimethoprim/sulfamethoxazole, cycloserine, and cefixime. ARGs encoding resistance against aminoglycoside, macrolide, quinolone, β-lactam, and tetracycline antibiotics were predominantly found in genomic DNA of the stool samples. Conclusion: We conclude that pregnancy-associated GM modulations may help to sustain a healthy pregnancy, but a higher proportion of antibiotic resistance could be deleterious for both maternal and fetal health.

RevDate: 2019-08-15

Sturød K, Dhariwal A, Dahle UR, et al (2019)

Impact of narrow spectrum Penicillin V on the oral and fecal resistome in a young child treated for otitis media.

Journal of global antimicrobial resistance pii:S2213-7165(19)30202-4 [Epub ahead of print].

BACKGROUND: Antibiotic overuse has led to a global emergence of resistant bacteria, and children are among the frequent users. Most studies with broad-spectrum antibiotics show severe impact on the resistome development of patients. Although narrow-spectrum antibiotics are believed to have less side-effects, their impact on the microbiome and resistome is mostly unknown. The aim of this study was to investigate the impact of the narrow-spectrum antibiotic phenoxymethylpenicillin (Penicillin V) on the microbiome and resistome of a child treated for acute otitis media (OM).

METHODS: Oral and fecal samples were collected from a one-year child before (day 0) and after (day 5 and 30) receiving Penicillin V against OM. Metagenomic sequencing data was analysed to determine taxonomic profiling, using Kraken and Bracken software, and resistance profiling, using KMA in combination with the ResFinder database.

RESULTS: In the oral samples, antimicrobial resistance genes (ARGs) belonging to four classes were identified at baseline. At day 5, the abundance of some ARGs was increased; some remained unchanged, while others disappeared. At day 30, most ARGs had returned to baseline levels, or lower. In the fecal samples, we observed seven ARGs at baseline and five at day 5. At day 30, the number increased to 21 ARGs from seven different classes.

CONCLUSIONS: Penicillin V had a remarkable impact on the fecal resistome indicating that even narrow-spectrum antibiotics may have important consequences in selecting for a more resistant microbiome.

RevDate: 2019-08-15

Tierney BT, Yang Z, Luber JM, et al (2019)

The Landscape of Genetic Content in the Gut and Oral Human Microbiome.

Cell host & microbe, 26(2):283-295.e8.

Despite substantial interest in the species diversity of the human microbiome and its role in disease, the scale of its genetic diversity, which is fundamental to deciphering human-microbe interactions, has not been quantified. Here, we conducted a cross-study meta-analysis of metagenomes from two human body niches, the mouth and gut, covering 3,655 samples from 13 studies. We found staggering genetic heterogeneity in the dataset, identifying a total of 45,666,334 non-redundant genes (23,961,508 oral and 22,254,436 gut) at the 95% identity level. Fifty percent of all genes were "singletons," or unique to a single metagenomic sample. Singletons were enriched for different functions (compared with non-singletons) and arose from sub-population-specific microbial strains. Overall, these results provide potential bases for the unexplained heterogeneity observed in microbiome-derived human phenotypes. One the basis of these data, we built a resource, which can be accessed at https://microbial-genes.bio.

RevDate: 2019-08-15

Ward LM, Idei A, Nakagawa M, et al (2019)

Geochemical and Metagenomic Characterization of Jinata Onsen, a Proterozoic-Analog Hot Spring, Reveals Novel Microbial Diversity including Iron-Tolerant Phototrophs and Thermophilic Lithotrophs.

Microbes and environments [Epub ahead of print].

Hydrothermal systems, including terrestrial hot springs, contain diverse geochemical conditions that vary over short spatial scales due to progressive interactions between reducing hydrothermal fluids, the oxygenated atmosphere, and, in some cases, seawater. At Jinata Onsen on Shikinejima Island, Japan, an intertidal, anoxic, iron-rich hot spring mixes with the oxygenated atmosphere and seawater over short spatial scales, creating diverse chemical potentials and redox pairs over a distance of ~10 m. We characterized geochemical conditions along the outflow of Jinata Onsen as well as the microbial communities present in biofilms, mats, and mineral crusts along its traverse using 16S rRNA gene amplicon and genome-resolved shotgun metagenomic sequencing. Microbial communities significantly changed downstream as temperatures and dissolved iron concentrations decreased and dissolved oxygen increased. Biomass was more limited near the spring source than downstream, and primary productivity appeared to be fueled by the oxidation of ferrous iron and molecular hydrogen by members of Zetaproteobacteria and Aquificae. The microbial community downstream was dominated by oxygenic Cyanobacteria. Cyanobacteria are abundant and active even at ferrous iron concentrations of ~150 μM, which challenges the idea that iron toxicity limited cyanobacterial expansion in Precambrian oceans. Several novel lineages of Bacteria are also present at Jinata Onsen, including previously uncharacterized members of the phyla Chloroflexi and Calditrichaeota, positioning Jinata Onsen as a valuable site for the future characterization of these clades.

RevDate: 2019-08-14

Nanto-Hara F, Kanemitsu Y, Fukuda S, et al (2019)

The guanylate cyclase C agonist linaclotide ameliorates the gut-cardio-renal axis in an adenine-induced mouse model of chronic kidney disease.

Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association pii:5549874 [Epub ahead of print].

BACKGROUND: Cardiorenal syndrome is a major cause of mortality in patients with chronic kidney disease (CKD). However, the involvement of detrimental humoral mediators in the pathogenesis of cardiorenal syndrome is still controversial. Trimethylamine-N-oxide (TMAO), a hepatic metabolic product of trimethylamine generated from dietary phosphatidylcholine or carnitine derived by the gut microbiota, has been linked directly with progression of cardiovascular disease and renal dysfunction. Thus, targeting TMAO may be a novel strategy for the prevention of cardiovascular disease and chronic kidney disease.

METHODS: Linaclotide, a guanylate cyclase C agonist, was administered to adenine-induced renal failure (RF) mice and changes in renal function and levels of gut-derived uremic toxins, as well as the gut microbiota community, were analyzed using metabolomic and metagenomic methods to reveal its cardiorenal effect.

RESULTS: Linaclotide decreased the plasma levels of TMAO at a clinically used low dose of 10 μg/kg in the adenine-induced RF mouse model. At a high concentration of 100 μg/kg, linaclotide clearly improved renal function and reduced the levels of various uremic toxins. A reduction in TMAO levels following linaclotide treatment was also observed in a choline-fed pro-atherosclerotic model. Linaclotide ameliorated renal inflammation and fibrosis and cardiac fibrosis, as well as decreased the expression of collagen I, transforming growth factor-β, galectin-3 (Gal-3) and ST2 genes. Plasma levels of Gal-3 and ST2 were also reduced. Because exposure of cardiomyocytes to TMAO increased fibronectin expression, these data suggest that linaclotide reduced the levels of TMAO and various uremic toxins and may result in not only renal, but also cardiac, fibrosis. F4/80-positive macrophages were abundant in small intestinal crypts in RF mice, and this increased expression was decreased by linaclotide. Reduced colonic claudin-1 levels were also restored by linaclotide, suggesting that linaclotide ameliorated the 'leaky gut' in RF mice. Metagenomic analysis revealed that the microbial order Clostridiales could be responsible for the change in TMAO levels.

CONCLUSION: Linaclotide reduced TMAO and uremic toxin levels and could be a powerful tool for the prevention and control of the cardiorenal syndrome by modification of the gut-cardio-renal axis.

RevDate: 2019-08-14

Peng M, Tabashsum Z, Patel P, et al (2019)

Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice.

Gut microbes [Epub ahead of print].

Probiotics are recognized for outcompeting pathogenic bacteria by competitive receptor-mediated colonization and secretion of functional metabolites which are antimicrobial against certain microbes as well as improving host's gut health and immunity. Recently, we have constructed a bioactive Lactobacillus casei (LC) strain, LC+mcra, by inserting mcra (myosin cross-reactive antigen) gene, which stimulates the conversion of conjugated linoleic acids. In this study, we evaluated the modulation of gut microbiome and protective roles of LC+mcra against pathogenic Salmonella enterica serovar Typhimurium (ST) and enterohemorrhagic E. coli (EHEC) infections in BALB/cJ mice. We observed that LC+mcra colonized efficiently in mice gut intestine and competitively reduced the infection with ST and EHEC in various locations of small and large intestine, specifically cecum, jejunum, and ileum (p < 0.05). Positive modulation of the cecal microbiota, for example, higher relative abundances of Firmicutes, lower relative abundances of Proteobacteria, and increased bacterial species diversity/richness, was detected in ST-challenged mice pretreated with LC+mcra based on 16S metagenomic sequencing. Cytokine gene expression analysis indicated that mice pretreated with LC+mcra associated with attenuated bacterial pathogen-induced gut inflammation. Furthermore, mice fed daily with LC+mcra for one week could protect themselves from the impairments caused by enteric infections with ST or EHEC. These impairments include weight loss, negative hematological changes, intestinal histological alterations, and potential death. This in vivo study suggests that daily consumption of novel conjugated linoleic acids over-producing probiotic effectively improves intestinal microbiota composition and prevents/combats foodborne enteric bacterial infections with pathogenic Salmonella and diarrheagenic E. coli.

RevDate: 2019-08-14

Petrovich ML, Ben Maamar S, Hartmann EM, et al (2019)

Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants.

Microbial biotechnology [Epub ahead of print].

Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.

RevDate: 2019-08-14

Sahoo RK, Das A, Sahoo K, et al (2019)

Characterization of novel metagenomic-derived lipase from Indian hot spring.

International microbiology : the official journal of the Spanish Society for Microbiology pii:10.1007/s10123-019-00095-z [Epub ahead of print].

Extreme environments are the main source of industrially suitable biocatalysts. The non-cultivable approach of searching enzymes is known to provide ample scope to accomplish novelty for their industrial applications. Lip479 clone out of seven lipase-producing clones obtained from Taptapani hot spring was found to be optimally active at pH 8.0 and temperature 65 °C. The recombinant Lip479 was highly stable in organic solvents, methanol, DMF, DMSO, acetone, and dichloromethane. Lip479 lipase activity was enhanced in the presence of K+, Mn2+, Na+, Zn2+, and Ca2+ except for Fe3+. The ability of Lip479 lipase to act on long carbon chain of 4-nitrophenyl myristate suggests it might be a true lipase. Lip479 clone was found to have ORF of 1251 bp encoding 416 amino acid residues of 42.57 KDa size (theoretically calculated). The presence of conserved motif Ala-His-Ser-Gln-Gly and Zn2+-binding consensus sequence (GAAHAAKH) of the clone assigns the protein to lipase family 1.5. Phylogenetic lineage of the protein sequence of Lip479 was traced to family 1.5 as it was clubbed up with those of reported lipases of the same family. The above biochemical features indicated that Lip479 lipase can be a potential biocatalyst for its use in various industries.

RevDate: 2019-08-14

Wang Z, Shi LD, Lai CY, et al (2019)

Methane oxidation coupled to vanadate reduction in a membrane biofilm batch reactor under hypoxic condition.

Biodegradation pii:10.1007/s10532-019-09887-6 [Epub ahead of print].

This study shows vanadate (V(V)) reduction in a methane (CH4) based membrane biofilm batch reactor when the concentration of dissolved oxygen (O2) was extremely low. V(IV) was the dominant products formed from V(V) bio-reduction, and majority of produced V(IV) transformed into precipitates with green color. Quantitative polymerase chain reaction and Illumina sequencing analysis showed that archaea methanosarcina were significantly enriched. Metagenomic predictive analysis further showed the enrichment of genes associated with reverse methanogenesis pathway, the key CH4-activating mechanism for anaerobic methane oxidation (AnMO), as well as the enrichment of genes related to acetate synthesis, in archaea. The enrichment of aerobic methanotrophs Methylococcus and Methylomonas implied their role in CH4 activation using trace level of O2, or their participation in V(V) reduction.

RevDate: 2019-08-14

Swe PM, Zakrzewski M, Waddell R, et al (2019)

High-throughput metagenome analysis of the Sarcoptes scabiei internal microbiota and in-situ identification of intestinal Streptomyces sp.

Scientific reports, 9(1):11744 pii:10.1038/s41598-019-47892-0.

Multiple parasitic arthropods of medical importance depend on symbiotic bacteria. While the link between scabies and secondary bacterial infections causing post infective complications of Group A streptococcal and staphylococcal pyoderma is increasingly recognized, very little is known about the microbiota of Sarcoptes scabiei. Here we analyze adult female mite and egg metagenome datasets. The majority of adult mite bacterial reads matched with Enterobacteriaceae (phylum Proteobacteria), followed by Corynebacteriaceae (phylum Actinobacteria). Klebsiella was the most dominant genus (78%) and Corynebacterium constituted 9% of the assigned sequences. Scabies mite eggs had a more diverse microbial composition with sequences from Proteobacteria being the most dominant (75%), while Actinobacteria, Bacteroidetes and Firmicutes accounted for 23% of the egg microbiome sequences. DNA sequences of a potential endosymbiont, namely Streptomyces, were identified in the metagenome sequence data of both life stages. The presence of Streptomyces was confirmed by conventional PCR. Digital droplet PCR indicated higher Streptomyces numbers in adult mites compared to eggs. Streptomyces were localized histologically in the scabies mite gut and faecal pellets by Fluorescent In Situ Hybridization (FISH). Streptomyces may have essential symbiotic roles in the scabies parasite intestinal system requiring further investigation.

RevDate: 2019-08-14

Posada-Perlaza CE, Ramírez-Rojas A, Porras P, et al (2019)

Bogotá River anthropogenic contamination alters microbial communities and promotes spread of antibiotic resistance genes.

Scientific reports, 9(1):11764 pii:10.1038/s41598-019-48200-6.

The increase in antibiotic resistant bacteria has raised global concern regarding the future effectiveness of antibiotics. Human activities that influence microbial communities and environmental resistomes can generate additional risks to human health. In this work, we characterized aquatic microbial communities and their resistomes in samples collected at three sites along the Bogotá River and from wastewaters at three city hospitals, and investigated community profiles and antibiotic resistance genes (ARGs) as a function of anthropogenic contamination. The presence of antibiotics and other commonly used drugs increased in locations highly impacted by human activities, while the diverse microbial communities varied among sites and sampling times, separating upstream river samples from more contaminated hospital and river samples. Clinically relevant antibiotic resistant pathogens and ARGs were more abundant in contaminated water samples. Tracking of resistant determinants to upstream river waters and city sources suggested that human activities foster the spread of ARGs, some of which were co-localized with mobile genetic elements in assembled metagenomic contigs. Human contamination of this water ecosystem changed both community structure and environmental resistomes that can pose a risk to human health.

RevDate: 2019-08-14

Zhang S, Song W, Wemheuer B, et al (2019)

Comparative Genomics Reveals Ecological and Evolutionary Insights into Sponge-Associated Thaumarchaeota.

mSystems, 4(4): pii:4/4/e00288-19.

Thaumarchaeota are frequently reported to associate with marine sponges (phylum Porifera); however, little is known about the features that distinguish them from their free-living thaumarchaeal counterparts. In this study, thaumarchaeal metagenome-assembled genomes (MAGs) were reconstructed from metagenomic data sets derived from the marine sponges Hexadella detritifera, Hexadella cf. detritifera, and Stylissa flabelliformis Phylogenetic and taxonomic analyses revealed that the three thaumarchaeal MAGs represent two new species within the genus Nitrosopumilus and one novel genus, for which we propose the names "CandidatusUNitrosopumilus hexadellus," "CandidatusUNitrosopumilus detritiferus," and "CandidatusUCenporiarchaeum stylissum" (the U superscript indicates that the taxon is uncultured). Comparison of these genomes to data from the Sponge Earth Microbiome Project revealed that "CaUCenporiarchaeum stylissum" has been exclusively detected in sponges and can hence be classified as a specialist, while "CaUNitrosopumilus detritiferus" and "CaUNitrosopumilus hexadellus" are also detected outside the sponge holobiont and likely lead a generalist lifestyle. Comparison of the sponge-associated MAGs to genomes of free-living Thaumarchaeota revealed signatures that indicate functional features of a sponge-associated lifestyle, and these features were related to nutrient transport and metabolism, restriction-modification, defense mechanisms, and host interactions. Each species exhibited distinct functional traits, suggesting that they have reached different stages of evolutionary adaptation and/or occupy distinct ecological niches within their sponge hosts. Our study therefore offers new evolutionary and ecological insights into the symbiosis between sponges and their thaumarchaeal symbionts.IMPORTANCE Sponges represent ecologically important models to understand the evolution of symbiotic interactions of metazoans with microbial symbionts. Thaumarchaeota are commonly found in sponges, but their potential adaptations to a host-associated lifestyle are largely unknown. Here, we present three novel sponge-associated thaumarchaeal species and compare their genomic and predicted functional features with those of closely related free-living counterparts. We found different degrees of specialization of these thaumarchaeal species to the sponge environment that is reflected in their host distribution and their predicted molecular and metabolic properties. Our results indicate that Thaumarchaeota may have reached different stages of evolutionary adaptation in their symbiosis with sponges.

RevDate: 2019-08-14
CmpDate: 2019-08-14

Kim YE, Ki CS, MA Jang (2019)

Challenges and Considerations in Sequence Variant Interpretation for Mendelian Disorders.

Annals of laboratory medicine, 39(5):421-429.

In 2015, the American College of Medical Genetics and Genomics (ACMG), together with the Association for Molecular Pathology (AMP), published the latest guidelines for the interpretation of sequence variants, which have been widely adopted into clinical practice. Despite these standardized efforts, the degrees of subjectivity and uncertainty allowed by the guidelines can lead to inconsistent variant classification across clinical laboratories, making it difficult to assess the pathogenicity of identified variants. We describe the critical elements of variant interpretation processes and potential pitfalls through practical examples and provide updated information based on a review of recent literature. The variant classification we describe is meant to be applicable to sequence variants for Mendelian disorders, whether identified by single-gene tests, multi-gene panels, exome sequencing, or genome sequencing. Continuing efforts to improve the reproducibility and objectivity of sequence variant interpretation across individuals and laboratories are needed.

RevDate: 2019-08-14
CmpDate: 2019-08-14

Kale SD (2019)

PenSeq: coverage you can count on.

The New phytologist, 221(3):1177-1179.

RevDate: 2019-08-13

Ari O, Karabudak S, Kalcioglu MT, et al (2019)

The bacteriome of otitis media with effusion: Does it originate from the adenoid?.

International journal of pediatric otorhinolaryngology, 126:109624 pii:S0165-5876(19)30368-4 [Epub ahead of print].

OBJECTIVE: The aim of this study was to evaluate the composition and the diversity of bacteriome in middle ear effusion (MEE) and adenoid specimens of pediatric patients having otitis media with effusion (OME).

MATERIALS AND METHODS: Sample collection from children with OME followed by next generation sequencing. Seventeen adenoid and 43 middle ear effusion specimens from 25 children having OME were evaluated. Microbiome analysis was performed via Ion 16S rRNA metagenomics kit.

RESULTS: Twenty-two different bacterial species were identified from all of the samples analyzed. There were variations in the prevalence and relative abundance of the bacteriome observed between adenoid and MEE samples. MEE microbiome was significantly dominated by Alloicoccus otitis (44%), Turicella otitidis (6%), and Staphylococcus auricularis (3%). Whereas, Rothia mucilaginosa (39%), R. dentocariosa (11%), S. aureus (5%), Veillonella rogosae (2%), Granulicatella elegans (2%), Granulicatella adiacens (2%), Eikenella corrodens (1%), and Prevotella nanceiensis (1%) had significantly higher relative abundance in adenoid samples. Overall, there was no statistically significant difference in alpha diversity of MEE and adenoid samples, whereas adenoid samples constituted a cluster in the beta diversity graph.

CONCLUSION: Bacteriome of MEE is mostly dominated by A. otitis yet accompanied by other bacteria with lower relative abundances suggests that OME is likely to be a polymicrobial process. Despite similarities, significant differences in relative abundances of several predominant species between bacteriome in the MEE and adenoid put the theory that OME in children is originated from the adenoids under question.

RevDate: 2019-08-13

Sofyan A, Uyeno Y, Shinkai T, et al (2019)

Metagenomic profiles of the rumen microbiota during the transition period in low-yield and high-yield dairy cows.

Animal science journal = Nihon chikusan Gakkaiho [Epub ahead of print].

We investigated potential relationships between rumen microbiota and milk production in dairy cows during the transition period. Twelve dairy cows were divided into a low-yield (LY) or high-yield (HY) group based on their milk yield. Rumen samples were taken from dairy cows at 3 weeks before parturition, and at 4, 8, and 12 weeks after parturition. 16S rDNA-based metagenomic analysis showed that diversities of rumen microbiota in both groups were similar and the number of operational taxonomic units (OTUs) was lower in the postpartum than prepartum period in both groups. The abundance of Bacteroidetes and ratio of Bacteroidetes:Firmicutes was higher in the HY than the LY group. OTUs assigned to Prevotella bryantii, Fibrobacter succinogenes, Ruminococcus albus, Butyrivibrio fibrisolvens, and Succinivibrio sp. were abundant in the HY group. These OTUs were significantly related to the propionate molar proportion of rumen fluids in the HY group. OTUs assigned to Lachnospiraceae, Bifidobacterium sp. and Saccharofermentans were dominant in the LY group. Predictive functional profiling revealed that abundance of gene families involved in amino acid and vitamin metabolism was higher in the HY than the LY group. These results suggest that the community structure and fermentation products of rumen microbiota could be associated with milk production of dairy cows.

RevDate: 2019-08-13

Li Y, Zhang C, Bell EW, et al (2019)

Ensembling multiple raw coevolutionary features with deep residual neural networks for contact-map prediction in CASP13.

Proteins [Epub ahead of print].

We report the results of residue-residue contact prediction of a new pipeline built purely on the learning of coevolutionary features in the CASP13 experiment. For a query sequence, the pipeline starts with the collection of multiple sequence alignments (MSAs) from multiple genome and metagenome sequence databases using two complementary HMM-based searching tools. Three profile matrices, built on covariance, precision, and pseudolikelihood maximization respectively, are then created from the MSAs, which are used as the input features of a deep residual convolutional neural network architecture for contact-map training and prediction. Two ensembling strategies have been proposed to integrate the matrix features through end-to-end training and stacking, resulting in two complementary programs called TripletRes and ResTriplet, respectively. For the 31 free-modeling (FM) domains that do not have homologous templates in the PDB, TripletRes and ResTriplet generated comparable results with an average accuracy of 0.640 and 0.646, respectively, for the top L/5 long-range predictions, where 71% and 74% of the cases have an accuracy above 0.5. Detailed data analyses showed that the strength of the pipeline is due to the sensitive MSA construction and the advanced strategies for coevolutionary feature ensembling. Domain splitting was also found to help enhance the contact prediction performance. Nevertheless, contact models for tail regions, which often involve a high number of alignment gaps, and for targets with few homologous sequences are still suboptimal. Development of new approaches where the model is specifically trained on these regions and targets might help address these problems. This article is protected by copyright. All rights reserved.

RevDate: 2019-08-13

Hu M, Lee M, Zhong L, et al (2019)

Method Development for DNA and Proteome SIP Analysis of Activated Sludge for Anaerobic Dichloromethane Biodegradation.

Methods in molecular biology (Clifton, N.J.), 2046:207-219.

Dichloromethane (DCM) is a toxic, dense non-aqueous phase liquid (DNAPL) that pollutes groundwater in all industrialized countries. Fortunately, DCM can be used as the sole source of energy and organic carbon by anaerobic microorganisms and be transformed to benign end products such as acetate, formate, and bicarbonate. However, knowledge around the phylogenetic diversity of anaerobic microorganisms capable of DCM metabolism is limited. The genes and enzymes involved and details of the reaction mechanism are not known. Stable isotope probing (SIP) is a technique used to identify microbes involved in assimilation of elements. The isotopically labeled substrate can be recovered in DNA and protein (i.e., DNA-SIP and protein-SIP) which enables identification of both the microbial taxa and their respective proteins involved in the substrate degradation. Therefore, by applying a combination of SIP techniques with molecular approaches (i.e., Illumina Miseq sequencing and metaproteomics), DCM degrading organisms can be identified and characterized in a manner independent of anaerobic enrichment cultures. In our research, activated sludge from wastewater treatment plant was fed with unlabeled and 13C-labeled DCM, respectively. Here, we provide protocols and technical notes for DNA and protein extraction from activated sludge and present analysis pipelines for downstream molecular techniques.

RevDate: 2019-08-13

Kröber E, Ö Eyice (2019)

Profiling of Active Microorganisms by Stable Isotope Probing-Metagenomics.

Methods in molecular biology (Clifton, N.J.), 2046:151-161.

Stable isotope probing (SIP) provides researchers a culture-independent method to retrieve nucleic acids from active microbial populations performing a specific metabolic activity in complex ecosystems. In recent years, the use of the SIP method in microbial ecology studies has been accelerated. This is partly due to the advances in sequencing and bioinformatics tools, which enable fast and reliable analysis of DNA and RNA from the SIP experiments. One of these sequencing tools, metagenomics, has contributed significantly to the body of knowledge by providing data not only on taxonomy but also on the key functional genes in specific metabolic pathways and their relative abundances. In this chapter, we provide a general background on the application of the SIP-metagenomics approach in microbial ecology and a workflow for the analysis of metagenomic datasets using the most up-to-date bioinformatics tools.

RevDate: 2019-08-13

Qi Z, Shi S, Tu J, et al (2019)

Comparative metagenomic sequencing analysis of cecum microbiotal diversity and function in broilers and layers.

3 Biotech, 9(8):316.

The composition of the gastrointestinal microorganisms in poultry is closely associated with the host and its environment. In this study, using 16S rRNA and metagenomic techniques, we comprehensively analyzed the structure and diversity of the cecal microbiota of broiler chickens (BC) and laying hens (LH). The 16S rRNA sequencing analysis showed Firmicutes, Bacteroidetes, and Proteobacteria were the main cecal bacterial phyla in BC and LH. However, at the genus level, LH had a greater abundance of Bacteroides (P < 0.05), Rikenellaceae_RC9_gut_group (P < 0.01), Phascolarctobacterium (P < 0.05), Desulfovibrio (P < 0.05), Prevotellaceae_UCG-001 (P < 0.05), and unclassified_o_Bacteroidales (P < 0.05), whereas BC had a greater abundance of Alistipes (P < 0.05), Rikenella (P < 0.05), Ruminococcaceae_UCG-005 (P < 0.05), Lachnoclostridium (P < 0.05), and unclassified_f_Ruminococcaceae (P < 0.05). It is particularly noteworthy that the genus Desulfovibrio was significantly more abundant in the LH cecum than in the BC cecum (P < 0.05). A metagenomic analysis showed that the annotations in the LH dataset were significantly more abundant than in the BC dataset, and included replication, recombination and repair, energy production and transformation, cell wall/membrane/envelope biogenesis, and amino acid transport and metabolism-related functions (P < 0.05). This study indicates that microbial genotypic differences in chickens of the same species can cause changes in the abundances of the gut microbiota, but do not alter the structural composition or major functional characteristics of the gut microbiota.

RevDate: 2019-08-13

Doan T, Hinterwirth A, Worden L, et al (2019)

Gut microbiome alteration in MORDOR I: a community-randomized trial of mass azithromycin distribution.

Nature medicine pii:10.1038/s41591-019-0533-0 [Epub ahead of print].

The MORDOR I trial1, conducted in Niger, Malawi and Tanzania, demonstrated that mass azithromycin distribution to preschool children reduced childhood mortality1. However, the large but simple trial design precluded determination of the mechanisms involved. Here we examined the gut microbiome of preschool children from 30 Nigerien communities randomized to either biannual azithromycin or placebo. Gut microbiome γ-diversity was not significantly altered (P = 0.08), but the relative abundances of two Campylobacter species, along with another 33 gut bacteria, were significantly reduced in children treated with azithromycin at the 24-month follow-up. Metagenomic analysis revealed functional differences in gut bacteria between treatment groups. Resistome analysis showed an increase in macrolide resistance gene expression in gut microbiota in communities treated with azithromycin (P = 0.004). These results suggest that prolonged mass azithromycin distribution to reduce childhood mortality reduces certain gut bacteria, including known pathogens, while selecting for antibiotic resistance.

RevDate: 2019-08-13

Gaia ASC, de Sá PHCG, de Oliveira MS, et al (2019)

NGSReadsTreatment - A Cuckoo Filter-based Tool for Removing Duplicate Reads in NGS Data.

Scientific reports, 9(1):11681 pii:10.1038/s41598-019-48242-w.

The Next-Generation Sequencing (NGS) platforms provide a major approach to obtaining millions of short reads from samples. NGS has been used in a wide range of analyses, such as for determining genome sequences, analyzing evolutionary processes, identifying gene expression and resolving metagenomic analyses. Usually, the quality of NGS data impacts the final study conclusions. Moreover, quality assessment is generally considered the first step in data analyses to ensure the use of only reliable reads for further studies. In NGS platforms, the presence of duplicated reads (redundancy) that are usually introduced during library sequencing is a major issue. These might have a serious impact on research application, as redundancies in reads can lead to difficulties in subsequent analysis (e.g., de novo genome assembly). Herein, we present NGSReadsTreatment, a computational tool for the removal of duplicated reads in paired-end or single-end datasets. NGSReadsTreatment can handle reads from any platform with the same or different sequence lengths. Using the probabilistic structure Cuckoo Filter, the redundant reads are identified and removed by comparing the reads with themselves. Thus, no prerequisite is required beyond the set of reads. NGSReadsTreatment was compared with other redundancy removal tools in analyzing different sets of reads. The results demonstrated that NGSReadsTreatment was better than the other tools in both the amount of redundancies removed and the use of computational memory for all analyses performed. Available in https://sourceforge.net/projects/ngsreadstreatment/ .

RevDate: 2019-08-13

Shang L, Hu Z, Deng Y, et al (2019)

Metagenomic Sequencing Identifies Highly Diverse Assemblages of Dinoflagellate Cysts in Sediments from Ships' Ballast Tanks.

Microorganisms, 7(8): pii:microorganisms7080250.

Ships' ballast tanks have long been known as vectors for the introduction of organisms. We applied next-generation sequencing to detect dinoflagellates (mainly as cysts) in 32 ballast tank sediments collected during 2001-2003 from ships entering the Great Lakes or Chesapeake Bay and subsequently archived. Seventy-three dinoflagellates were fully identified to species level by this metagenomic approach and single-cell polymerase chain reaction (PCR)-based sequencing, including 19 toxic species, 36 harmful algal bloom (HAB) forming species, 22 previously unreported as producing cysts, and 55 reported from ballast tank sediments for the first time (including 13 freshwater species), plus 545 operational taxonomic units (OTUs) not fully identified due to a lack of reference sequences, indicating tank sediments are repositories of many previously undocumented taxa. Analyses indicated great heterogeneity of species composition among samples from different sources. Light and scanning electron microscopy and single-cell PCR sequencing supported and confirmed results of the metagenomic approach. This study increases the number of fully identified dinoflagellate species from ballast tank sediments to 142 (> 50% increase). From the perspective of ballast water management, the high diversity and spatiotemporal heterogeneity of dinoflagellates in ballast tanks argues for continuing research and stringent adherence to procedures intended to prevent unintended introduction of non-indigenous toxic and HAB-forming species.

RevDate: 2019-08-12

Chiu KP, AL Yu (2019)

Application of cell-free DNA sequencing in characterization of bloodborne microbes and the study of microbe-disease interactions.

PeerJ, 7:e7426 pii:7426.

It is an important issue whether microorganisms can live harmoniously with normal cells in the cardiovascular system. The answer to the question will have enormous impact on medical microbiology. To address the issue, it is essential to identify and characterize the bloodborne microbes in an efficient and comprehensive manner. Due to microbial sequence complexity and the composition of significant number of unknown microbial species in the circulatory system, traditional approaches using cell culture, PCR, or microarray are not suitable for the purpose. Recent reports indicate that cell-free DNA (cfDNA) sequencing using next-generation sequencing (NGS) or single-molecule sequencing (SMS), together with bioinformatics approaches, possesses a strong potential enabling us to distinguish microbial species at the nucleotide level. Multiple studies using microbial cfDNA sequencing to identify microbes for septic patients have shown strong agreement with cell culture. Similar approaches have also been applied to reveal previously unidentified microorganisms or to demonstrate the feasibility of comprehensive assessment of bloodborne microorganisms for healthy and/or diseased individuals. SMS using either SMRT (single-molecule real-time) sequencing or Nanopore sequencing are providing new momentum to reinforce this line of investigation. Taken together, microbial cfDNA sequencing provides a novel opportunity allowing us to further understand the involvement of bloodborne microbes in development of diseases. Similar approaches should also be applicable to the study of metagenomics for sufficient and comprehensive analysis of microbial species living in various environments. This article reviews this line of research and discuss the methodological approaches that have been developed, or are likely to be developed in the future, which may have strong potential to facilitate cfDNA- and cfRNA-based studies of cancer and acute/chronic diseases, in the hope that a better understanding of the hidden microbes in the circulatory system will improve diagnosis, prevention and treatment of problematic diseases.

RevDate: 2019-08-12

Yurgel SN, Nearing JT, Douglas GM, et al (2019)

Metagenomic Functional Shifts to Plant Induced Environmental Changes.

Frontiers in microbiology, 10:1682.

The Vaccinium angustifolium (wild blueberry) agricultural system involves transformation of the environment surrounding the plant to intensify plant propagation and to improve fruit yield, and therefore is an advantageous model to study the interaction between soil microorganisms and plant-host interactions. We studied this system to address the question of a trade-off between microbial adaptation to a plant-influenced environment and its general metabolic capabilities. We found that many basic metabolic functions were similarly represented in bulk soil and rhizosphere microbiomes overall. However, we identified a niche-specific difference in functions potentially beneficial for microbial survival in the rhizosphere but that might also reduce the ability of microbes to withstand stresses in bulk soils. These functions could provide the microbiome with additional capabilities to respond to environmental fluctuations in the rhizosphere triggered by changes in the composition of root exudates. Based on our analysis we hypothesize that the rhizosphere-specific pathways involved in xenobiotics biodegradation could provide the microbiome with functional flexibility to respond to plant stress status.

RevDate: 2019-08-12

Abdelfattah A, Sanzani SM, Wisniewski M, et al (2019)

Revealing Cues for Fungal Interplay in the Plant-Air Interface in Vineyards.

Frontiers in plant science, 10:922.

Plant-associated microorganisms play a crucial role in plant health and productivity. Belowground microbial diversity is widely reported as a major factor in determining the composition of the plant microbiome. In contrast, much less is known about the role of the atmosphere in relation to the plant microbiome. The current study examined the hypothesis that the atmospheric microbiome influences the composition of fungal communities of the aboveground organs (flowers, fruit, and leaves) of table grape and vice versa. The atmosphere surrounding grape plantings exhibited a significantly higher level of fungal diversity relative to the nearby plant organs and shared a higher number of phylotypes (5,536 OTUs, 40.3%) with the plant than between organs of the same plant. Using a Bayesian source tracking approach, plant organs were determined to be the major source of the atmospheric fungal community (92%). In contrast, airborne microbiota had only a minor contribution to the grape microbiome, representing the source of 15, 4, and 35% of the fungal communities of leaves, flowers, and fruits, respectively. Moreover, data indicate that plant organs and the surrounding atmosphere shared a fraction of each other's fungal communities, and this shared pool of fungal taxa serves as a two-way reservoir of microorganisms. Microbial association analysis highlighted more positive than negative interactions between fungal phylotypes. Positive interactions were more common within the same environment, while negative interactions appeared to occur more frequently between different environments, i.e., atmosphere, leaf, flower, and fruit. The current study revealed the interplay between the fungal communities of the grape phyllosphere with the surrounding air. Plants were identified as a major source of recruitment for the atmospheric microbiome, while the surrounding atmosphere contributed only a small fraction of the plant fungal community. The results of the study suggested that the plant-air interface modulates the plant recruitment of atmospheric fungi, taking a step forward in understanding the plant holobiont assembly and how the atmosphere surrounding plants plays a role in this process. The impact of plants on the atmospheric microbiota has several biological and epidemiological implications for plants and humans.

RevDate: 2019-08-12

Beck BR, Park GS, Jeong DY, et al (2019)

Multidisciplinary and Comparative Investigations of Potential Psychobiotic Effects of Lactobacillus Strains Isolated From Newborns and Their Impact on Gut Microbiota and Ileal Transcriptome in a Healthy Murine Model.

Frontiers in cellular and infection microbiology, 9:269.

Psychobiotics are probiotic microorganisms that may exert positive influence on the psychological status of the host. Studies have revealed immunological and microbiological correlations of gut microbiota and the gut-brain axis, and have investigated psychobiotics based on the findings of the gut-brain axis. Considering their mode of actions, the present study sets anti-inflammatory effect, neurotransmitter modulation, and gut microbiota modulation as three essential criteria to evaluate Lactobacillus casei ATG-F1 (F1), L. reuteri ATG-F3 (F3), and L. reuteri ATG-F4 (F4) isolated from newborns as psychobiotics candidates in a healthy mouse model and compares the results with a non-treated control group and an ampicillin-induced gut dysbiosis (Amp) group as a negative control. The F3 and F4 strains showed anti-inflammatory effects in vitro in RAW264.7 murine macrophages, and the level of anti-inflammatory cytokine interleukin (IL)-10 increased in ileums of mice orally administered with the F4 strain. Serum dopamine level significantly increased only in the F4-treated group as compared with the control group. Serum serotonin level was unaffected in Lactobacillus-treated groups, while a significant decrease in serum serotonin level was observed in the Amp group. Bacteroidetes population increased in fecal samples of the F4-treated group as compared with the control, and Bacteroidales S24-7 and Prevotellaceae population significantly increased at family level in fecal samples from the F4-treated group as compared with the control. In contrast, the Amp group showed an increase in the level of Proteobacteria and a decrease in the level of Bacteroidetes as compared with the control group. Transcriptome analysis revealed a distinctive clustering in ileums from the F4-treated group as compared to other experimental groups. In addition, the circadian rhythm pathway showed maximum enrichment in ileums of Lactobacillus-treated mice, and the F4-treated group showed the highest fold changes in circadian rhythm-related genes (Dbp, Per1, Per2, and Per3). Conclusively, L. reuteri ATG-F4 is suggested as a potential psychobiotics through demonstrations of anti-inflammatory effects, serum dopamine modulation, and gut microbiota modulation in a healthy murine model in the present study. Moreover, we carefully suggest gut circadian rhythm modulation as another important criterion of psychobiotics, which may have an important role in the gut-brain axis.

RevDate: 2019-08-12

Mora D, Filardi R, Arioli S, et al (2019)

Development of omics-based protocols for the microbiological characterization of multi-strain formulations marketed as probiotics: the case of VSL#3.

Microbial biotechnology [Epub ahead of print].

The growing commercial interest in multi-strain formulations marketed as probiotics has not been accompanied by an equal increase in the evaluation of quality levels of these biotechnological products. The multi-strain product VSL#3 was used as a model to setup a microbiological characterization that could be extended to other formulations with high complexity. Shotgun metagenomics by deep Illumina sequencing was applied to DNA isolated from the commercial VSL#3 product to confirm strains identity safety and composition. Single-cell analysis was used to evaluate the cell viability, and β-galactosidase and urease activity have been used as marker to monitor the reproducibility of the production process. Similarly, these lots were characterized in detail by a metaproteomics approach for which a robust protein extraction protocol was combined with advanced mass spectrometry. The results identified over 1600 protein groups belonging to all strains present in the VSL#3 formulation. Of interest, only 3.2 % proteins showed significant differences mainly related to small variations in strain abundance. The protocols developed in this study addressed several quality criteria that are relevant for marketed multi-strain products and these represent the first efforts to define the quality of complex probiotic formulations such as VSL#3.

RevDate: 2019-08-12
CmpDate: 2019-08-12

Estrada-Peña A, Cabezas-Cruz A, Pollet T, et al (2018)

High Throughput Sequencing and Network Analysis Disentangle the Microbial Communities of Ticks and Hosts Within and Between Ecosystems.

Frontiers in cellular and infection microbiology, 8:236.

We aimed to develop a framework, based on graph theory, to capture the ecological meaning behind pure pair comparisons of microbiome-derived data. As a proof of concept, we applied the framework to analyze the co-occurrence of bacteria in either Ixodes ricinus ticks or the spleen of one of their main hosts, the vole Myodes glareolus. As a secondary lymphoid organ, the spleen acts as a filter of blood and represents well the exposure to microorganisms circulating in the blood; including those acquired and transmitted by ticks during feeding. The microbiome of 301 and 269 individual tick and vole samples, respectively, were analyzed using next generation sequencing (NGS) of 16S rRNA. To assess the effect of habitat on ecological communities of bacteria associated to ticks and voles, two different biotopes were included in the study, forest, and ecotone. An innovative approach of NGS data analysis combining network analysis and phylogenies of co-occuring of bacteria was used to study associations between bacteria in individual samples. Of the 126 bacterial genera found in ticks and voles, 62% were shared by both species. Communities of co-occurring bacteria were always more phylogenetically diverse in ticks than in voles. Interestingly, ~80% of bacterial phylogenetic diversity was found in ~20% of ticks. This pattern was not observed in vole-associated bacteria. Results revealed that the microbiome of I. ricinus is only slightly related to that of M. glareolus and that the biotope plays the most important role in shaping the bacterial communities of either ticks or voles. The analysis of the phylogenetic signal of the network indexes across the 16S rRNA-derived tree of bacteria suggests that the microbiome of both ticks and voles has high phylogenetic diversity and that closest bacterial genera do not co-occur. This study shows that network analysis is a promising tool to unravel complex microbial communities associated to arthropod vectors and vertebrate hosts.

RevDate: 2019-08-13
CmpDate: 2019-08-13

Cooke NP, S Nakagome (2018)

Fine-tuning of Approximate Bayesian Computation for human population genomics.

Current opinion in genetics & development, 53:60-69.

Approximate Bayesian Computation (ABC) is a flexible statistical tool widely applied to addressing a variety of questions regarding the origin and evolution of humans. The significant growth of genomic scale data from diverse geographic populations has facilitated the use of ABC in modelling the complex processes that underlie human demography and local adaptation. However, a fundamental issue still remains in how to efficiently capture patterns of genetic variation with a set of summary statistics in order to achieve better approximation of Bayesian inference. Here, we review recent advances in ABC methodology and its applications for human population genomics, with a particular focus on optimal tuning of ABC approaches for different types of genetic data and different sets of evolutionary parameters.

RevDate: 2019-08-11

Yeruva T, Vankadara S, Ramasamy S, et al (2019)

Identification of Potential Probiotics in the Midgut of Mulberry Silkworm, Bombyx mori Through Metagenomic Approach.

Probiotics and antimicrobial proteins pii:10.1007/s12602-019-09580-3 [Epub ahead of print].

Microorganisms play an important role in the growth and development of numerous insect species. The mulberry silkworm, Bombyx mori (Lepidoptera), harbors several bacteria in its midgut aiding the metabolic processes; however, the variability of bacterial spp. present in the midgut and their role(s) in the growth and development of the silkworm are poorly understood. The present work compares the diversity of midgut bacterial communities in silkworms of variable voltinism (Pure Mysore, PM: multivoltine; CSR2: bivoltine and PM × CSR2: crossbreed) through metagenomics. The predominance of Enterococcus (30.30%) followed by Bacillus (16.96%) was observed in PM, whereas Lactobacillus (56.56%) followed by Enterococcus (10.58%) was seen only in CSR2. Interestingly, crossbreed midgut harbored diverse bacterial communities (36.21% Lactobacillus, 25.94% Bacillus, 8.1% Enterococcus, and 18.37% uncultured bacteria). Metagenomic profiles indicate variability in the gut bacterial population in different kinds of silkworms influencing the physiological activities accordingly. The dominant bacteria, particularly lactobacilli, bacilli, and enterococci could be further explored for identifying the potential probiotic consortia based on a literature survey and potential involvement in nutrient absorption, disease/stress tolerance, and improved economic traits.

RevDate: 2019-08-11

Chen R, Wang J, Zhan R, et al (2019)

Fecal metabonomics combined with 16S rRNA gene sequencing to analyze the changes of gut microbiota in rats with kidney-yang deficiency syndrome and the intervention effect of You-gui pill.

Journal of ethnopharmacology pii:S0378-8741(19)31428-X [Epub ahead of print].

A myriad of evidence have shown that kidney-yang deficiency syndrome (KYDS) is associated with metabolic disorders of the intestinal microbiota, while TCMs can treat KYDS by regulating gut microbiota metabolism. However, the specific interplay between KYDS and intestinal microbiota, and the intrinsic regulation mechanism of You-gui pill (YGP) on KYDS' gut microbiota remains largely unknown so far.

MATERIALS AND METHODS: In the present study, fecal metabonomics combined with 16S rRNA gene sequencing analysis were used to explore the mutual effect between KYDS and intestinal flora, and the intrinsic regulation mechanism of YGP on KYDS's gut microbiota. Rats' feces from control (CON) group, KYDS group and YGP group were collected, and metabolomic analysis was performed using 1H NMR technique combined with multivariate statistical analysis to obtain differential metabolites. Simultaneously, 16S rRNA gene sequencing analysis based on the Illumina HiSeq sequencing platform and ANOVA analysis were used to analyze the composition of the intestinal microbiota in the stool samples and to screen for the significant altered microbiota at the genus level. After that, MetaboAnalyst database and PICRUSt software were apply to conduct metabolic pathway analysis and functional prediction analysis of the screened differential metabolites and intestinal microbiota, respectively. What's more, Pearson correlation analysis was performed on these differential metabolites and gut microbiota.

RESULTS: Using fecal metabonomics, KYDS was found to be associated with 21 differential metabolites and seven potential metabolic pathways. These metabolites and metabolic pathways were mainly involved in amino acid metabolism, energy metabolism, methylamine metabolism, bile acid metabolism and urea cycle, and short-chain fatty acid metabolism. Through 16S rRNA gene sequencing analysis, we found that KYDS was related to eleven different intestinal microbiotas. These gut microbiota were mostly involved in amino acid metabolism, energy metabolism, nervous, endocrine, immune and digestive system, lipid metabolism, and carbohydrate metabolism. Combined fecal metabonomics and 16S rRNA gene sequencing analysis, we further discovered that KYDS was primarily linked to three gut microbiotas (i.e. Bacteroides, Desulfovibrio and [Eubacterium]_coprostanoligenes_group) and eleven related metabolites (i.e. deoxycholate, n-butyrate, valine, isoleucine, acetate, taurine, glycine, α-gluconse, β-glucose, glycerol and tryptophan) mediated various metabolic disorders (amino acid metabolism, energy metabolism, especially methylamine metabolism, bile acid metabolism and urea cycle, short-chain fatty acid metabolism. nervous, endocrine, immune and digestive system, lipid metabolism, and carbohydrate metabolism). YGP, however, had the ability to mediate four kinds of microbes (i.e. Ruminiclostridium_9, Ruminococcaceae_UCG-007, Ruminococcaceae_UCG-010, and uncultured_bacterium_f_Bacteroidales_S24-7_group) and ten related metabolites (i.e. deoxycholate, valine, isoleucine, alanine, citrulline, acetate, DMA, TMA, phenylalanine and tryptophan) mediated amino acid metabolism, especially methylamine metabolism, bile acid metabolism and urea cycle, short-chain fatty acid metabolism, endocrine, immune and digestive system, and lipid metabolism, thereby exerting a therapeutic effect on KYDS rats.

CONCLUSION: Overall, our findings have preliminary confirmed that KYDS is closely related to metabolic and microbial dysbiosis, whereas YGP can improve the metabolic disorder of KYDS by acting on intestinal microbiota. Meanwhile, this will lay the foundation for the further KYDS's metagenomic research and the use of intestinal microbiotas as drug targets to treat KYDS.

RevDate: 2019-08-10

Ceccon DM, Faoro H, Lana PDC, et al (2019)

Metataxonomic and metagenomic analysis of mangrove microbiomes reveals community patterns driven by salinity and pH gradients in Paranaguá Bay, Brazil.

The Science of the total environment, 694:133609 pii:S0048-9697(19)33534-X [Epub ahead of print].

While environmental drivers regulate the structure of mangrove microbial communities, their exact nature and the extent of their influence require further elucidation. By means of 16S rRNA gene-based sequencing, we determined the microbial taxonomic profiles of mangroves in the subtropical Paranaguá Bay, Brazil, considering as potential drivers: salinity, as represented by two sectors in the extremes of a salinity gradient (<5 PSU and >30 PSU); proximity to/absence of the prevailing plants, Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, and Spartina alterniflora; and the chemical composition of the sediments. Salinity levels within the estuary had the strongest influence on microbial structure, and pH was important to separate two communities within the high salinity environment. About one fourth of the total variation in community structure resulted from covariation of salinity and the overall chemical composition, which might indicate that the chemical profile was also related to salinity. The most prevalent bacterial phyla associated with the mangrove soils analyzed included Proteobacteria, Actinobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, and Cyanobacteria. Taxonomic and functional comparisons of our results for whole-genome sequencing with available data from other biomes showed that the studied microbiomes cluster first according to biome type, then to matrix type and salinity status. Metabolic functions were more conserved than organisms within mangroves and across all biomes, indicating that core functions are preserved in any of the given conditions regardless of the specific organisms harboring them.

RevDate: 2019-08-10

Mougari S, Sahmi-Bounsiar D, Levasseur A, et al (2019)

Virophages of Giant Viruses: An Update at Eleven.

Viruses, 11(8): pii:v11080733.

The last decade has been marked by two eminent discoveries that have changed our perception of the virology field: The discovery of giant viruses and a distinct new class of viral agents that parasitize their viral factories, the virophages. Coculture and metagenomics have actively contributed to the expansion of the virophage family by isolating dozens of new members. This increase in the body of data on virophage not only revealed the diversity of the virophage group, but also the relevant ecological impact of these small viruses and their potential role in the dynamics of the microbial network. In addition, the isolation of virophages has led us to discover previously unknown features displayed by their host viruses and cells. In this review, we present an update of all the knowledge on the isolation, biology, genomics, and morphological features of the virophages, a decade after the discovery of their first member, the Sputnik virophage. We discuss their parasitic lifestyle as bona fide viruses of the giant virus factories, genetic parasites of their genomes, and then their role as a key component or target for some host defense mechanisms during the tripartite virophage-giant virus-host cell interaction. We also present the latest advances regarding their origin, classification, and definition that have been widely discussed.

RevDate: 2019-08-09

Kneis D, Berendonk TU, S Heß (2019)

High prevalence of colistin resistance genes in German municipal wastewater.

The Science of the total environment, 694:133454 pii:S0048-9697(19)33374-1 [Epub ahead of print].

Bacterial resistance against the last-resort antibiotic colistin is of increasing concern on a global scale. Wastewater is suspected to be one of the pathways by which resistant bacteria and the respective genes are disseminated. We employed a metagenomics approach to detect and quantify colistin resistance genes in raw municipal wastewater sampled at 9 locations all over Germany (14 samples in total, collected in 2016/2017). Our data support the findings of earlier studies according to which the prevalence of the colistin resistance gene mcr-1 is still low. However, we were able to demonstrate that the total prevalence of colistin resistance genes is dramatically underestimated if the focus is put on that specific gene alone. In comparison to mcr-1, other gene variants like mcr-3 and mcr-7 proved to be 10 to 100 times more abundant in samples of untreated wastewater. The average relative abundances expressed as copies per 16S rRNA gene copies were 2.3×10-3 for mcr-3, 2.2×10-4 for mcr-4, 3.0×10-4 for mcr-5, and 4.4×10-4 for mcr-7. While these four gene variants were ubiquitous in all 14 samples, mcr-1 was detected only once at a relative abundance of 1.4×10-5. Our results suggest a high risk of increasing incidence of colistin resistance as large amounts of mcr genes are continuously disseminated to diverse microbial communities via the wastewater path.

RevDate: 2019-08-09

Jerome H, Taylor C, Sreenu VB, et al (2019)

Metagenomic next-generation sequencing aids the diagnosis of viral infections in febrile returning travellers.

The Journal of infection pii:S0163-4453(19)30242-7 [Epub ahead of print].

OBJECTIVES: Travel-associated infections are challenging to diagnose because of the broad spectrum of potential aetiologies. As a proof-of-principle study, we used MNGS to identify viral pathogens in clinical samples from returning travellers in a single centre to explore its suitability as a diagnostic tool.

METHODS: Plasma samples from 40 returning travellers presenting with a fever of ≥38°C were retrospectively sequenced using MNGS on the Illumina MiSeq platform and compared with standard-of-care diagnostic assays.

RESULTS: In total, 11/40 patients were diagnosed with a viral infection. Standard of care diagnostics revealed 5 viral infections using plasma samples; dengue virus 1 (n=2), hepatitis E (n=1), Ebola virus (n=1) and hepatitis A (n=1), all of which were detected by MNGS. Three additional patients with Chikungunya virus (n=2) and mumps virus were diagnosed by MNGS only. Respiratory infections detected by nasal/throat swabs only were not detected by MNGS of plasma. One patient had infection with malaria and mumps virus during the same admission.

CONCLUSIONS: MNGS analysis of plasma samples improves the sensitivity of diagnosis of viral infections and has potential as an all-in-one diagnostic test. It can be used to identify infections that have not been considered by the treating physician, co-infections and new or emerging pathogens.

SUMMARY: Next generation sequencing (NGS) has potential as an all-in-one diagnostic test. In this study we used NGS to diagnose returning travellers with acute febrile illness in the UK, highlighting cases where the diagnosis was missed using standard methods.

RevDate: 2019-08-09

Katsuta R, Sunaga F, Oi T, et al (2019)

First identification of Sapoviruses in wild boar.

Virus research pii:S0168-1702(19)30431-9 [Epub ahead of print].

Sapoviruses (SaVs) are enteric viruses that have been detected in human and animals previously; however, SaVs have not been identified in wild boar yet. Using a metagenomics approach, we identified SaVs in fecal samples of free-living wild boars in Japan for the first time. Six of the 48 specimens identified belonged to one genogroup (G)III, one GV and four GVI SaV sequence reads. We successfully determined complete genome of GV and GVI SaV strains using the long reverse transcription PCR strategy and the 5' rapid amplification of cDNA end method. Phylogenetic tree analysis and pairwise distance calculation revealed that GV SaV detected from wild boar was related to recently assigned GV.5 strains from pig, while GVI SaV was assigned to a new genotype within GVI. Moreover, wild boar may act as a reservoir for transmission of SaVs to the pig population (and vice versa) because GIII, GV, and GVI SaVs were all detected in pigs previously.

RevDate: 2019-08-09

Ye SH, Siddle KJ, Park DJ, et al (2019)

Benchmarking Metagenomics Tools for Taxonomic Classification.

Cell, 178(4):779-794.

Metagenomic sequencing is revolutionizing the detection and characterization of microbial species, and a wide variety of software tools are available to perform taxonomic classification of these data. The fast pace of development of these tools and the complexity of metagenomic data make it important that researchers are able to benchmark their performance. Here, we review current approaches for metagenomic analysis and evaluate the performance of 20 metagenomic classifiers using simulated and experimental datasets. We describe the key metrics used to assess performance, offer a framework for the comparison of additional classifiers, and discuss the future of metagenomic data analysis.

RevDate: 2019-08-09

Lendemer JC, Keepers KG, Tripp EA, et al (2019)

A taxonomically broad metagenomic survey of 339 species spanning 57 families suggests cystobasidiomycete yeasts are not ubiquitous across all lichens.

American journal of botany [Epub ahead of print].

PREMISE: Lichens are fungi that enter into obligate symbioses with photosynthesizing organisms (algae, cyanobacteria). Traditional narratives of lichens as binary symbiont pairs have given way to their recognition as dynamic metacommunities. Basidiomycete yeasts, particularly of the genus Cyphobasidium, have been inferred to be widespread and important components of lichen metacommunities. Yet, the presence of basidiomycete yeasts across a wide diversity of lichen lineages has not previously been tested.

METHODS: We searched for lichen-associated cystobasidiomycete yeasts in newly generated metagenomic data from 413 samples of 339 lichen species spanning 57 families and 25 orders. The data set was generated as part of a large-scale project to study lichen biodiversity gradients in the southern Appalachian Mountains Biodiversity Hotspot of southeastern North America.

RESULTS: Our efforts detected cystobasidiomycete yeasts in nine taxa (Bryoria nadvornikiana, Heterodermia leucomelos, Lecidea roseotincta, Opegrapha vulgata, Parmotrema hypotropum, P. subsumptum, Usnea cornuta, U. strigosa, and U. subgracilis), representing 2.7% of all species sampled. Seven of these taxa (78%) are foliose (leaf-like) or fruticose (shrubby) lichens that belong to families where basidiomycete yeasts have been previously detected. In several of the nine cases, cystobasidiomycete rDNA coverage was comparable to, or greater than, that of the primary lichen fungus single-copy nuclear genomic rDNA, suggesting sampling artifacts are unlikely to account for our results.

CONCLUSIONS: Studies from diverse areas of the natural sciences have led to the need to reconceptualize lichens as dynamic metacommunities. However, our failure to detect cystobasidiomycetes in 97.3% (330 species) of the sampled species suggests that basidiomycete yeasts are not ubiquitous in lichens.

RevDate: 2019-08-09

Happel EM, Markussen T, Teikari JE, et al (2019)

Effects of allochthonous DOM input on microbial composition and nitrogen cycling genes at two contrasting estuarine sites.

FEMS microbiology ecology pii:5545591 [Epub ahead of print].

Heterotrophic bacteria are important drivers of nitrogen (N) cycling and the processing of dissolved organic matter (DOM). Projected increases in precipitation will potentially cause increased loads of riverine DOM to the Baltic Sea and likely affect the composition and function of bacterioplankton communities. To investigate this, the effects of riverine DOM from two different catchment areas (agricultural and forest) on natural bacterioplankton assemblages from two contrasting sites in the Baltic Sea were examined. Two microcosm experiments were carried out, where the community composition (16S rRNA gene sequencing), the composition of a suite of N cycling genes (metagenomics), and the abundance and transcription of ammonia monooxygenase (amoA) genes involved in nitrification (quantitative PCR) were investigated. The river water treatments evoked a significant response in bacterial growth, but effects on overall community composition and the representation of N cycling genes were limited. Instead, treatment effects were reflected in the prevalence of specific taxonomic families, specific N related functions, and in the transcription of amoA genes. The study suggests that bacterioplankton responses to changes in the DOM pool are constrained to part of the bacterial community, whereas most taxa remain relatively unaffected.

RevDate: 2019-08-09

Lv Y, Qin X, Jia H, et al (2019)

The Association between Gut Microbiota Composition and Body Mass Index in Chinese Male College Students, as Analyzed by Next-generation Sequencing.

The British journal of nutrition pii:S0007114519001909 [Epub ahead of print].

Altered gut microbial ecology contributes to the development of metabolic diseases including obesity. However, studies based on different populations have generated conflicting results due to diet, environment, methodologies, etc. The aim of our study was to explore the association between gut microbiota and Body Mass Index (BMI) in Chinese college students. 16S next-generation sequencing (NGS) was used to test the gut microbiota of 9 lean, 9 overweight/obesity, and 10 normal-weight male college students. The differences of gut microbiota distribution among three groups were compared, and the relationship between the richness, diversity, composition of gut microbiota and BMI were analyzed. The predominant phyla Bacteroidetes and Firmicutes were further confirmed by real-time PCR. Metagenomic biomarker discovery was conducted by Linear discriminant analysis (LDA) Effect Size (LEfSe). NGS revealed that gut microbiota composition was different among three groups, but there was no difference in the abundance ratio of Firmicutes/ Bacteroidetes. Several bacterial taxa were in linear relationship with BMI (positive relationship: uncultured bacterium (Bacteroides genus); negative relationship: Porphyromonadaceae, Acidaminococcaceae, Rikenellaceae, Desulfovibrionaceae, Blautia, Anaerotruncus, Parabacteroides, Alistipes). Moreover, gut microbiota diversity decreased with the increase of BMI. And LEfSe analyze indicated that Blautia, Anaerotruncus and its uncultured species were significantly enriched in the lean group (LDA score≥3), Parasuterella and its uncultured species were significantly enriched in the overweight/obese groups(LDA score≥3). In general, gut microbiota composition and microbial diversity were associated with BMI in Chinese male college students. Our results might enrich the understanding between gut microbiota and obesity.

RevDate: 2019-08-09

Payne D, Dunham EC, Mohr E, et al (2019)

Geologic legacy spanning >90 years explains unique Yellowstone hot spring geochemistry and biodiversity.

Environmental microbiology [Epub ahead of print].

Little is known about how the geological history of an environment shapes its physical and chemical properties and how these, in turn, influence the assembly of communities. Evening Primrose (EP), a moderately acidic hot spring (pH 5.6, 77.4°C) in Yellowstone National Park (YNP), has undergone dramatic physicochemical change linked to seismic activity. Here, we show that this legacy of geologic change led to the development of an unusual sulfur-rich, anoxic chemical environment that supports a unique archaeal-dominated and anaerobic microbial community. Metagenomic sequencing and informatics analyses reveal that >96% of this community is supported by dissimilatory reduction or disproportionation of inorganic sulfur compounds, including a novel, deeply diverging sulfate reducing thaumarchaeote. When compared to other YNP metagenomes, the inferred functions of EP populations were like those from sulfur-rich acidic springs, suggesting that sulfur may overprint the predominant influence of pH on the composition of hydrothermal communities. Together, these observations indicate that the dynamic geological history of EP underpins its unique geochemistry and biodiversity, emphasizing the need to consider the legacy of geologic change when describing processes that shape the assembly of communities. Originality-Significance Statement All environments are geologically dynamic over varying timescales. However, how the legacy of geologic change influences the physical and chemical properties of an environment and how these, in turn, influence the assembly of microbiomes is understudied. Here, we examine the recent geologic history of a well-studied hydrothermal system in Yellowstone National Park and show that its legacy of geologic change led to the development of an unusual sulfur-rich, anoxic chemical environment that supports a unique archaeal-dominated microbiome. The energy metabolism of >96% of the community is supported by anaerobic dissimilation of inorganic sulfur, including that of a novel sulfate reducing thaumarchaote. The results provide new insight into thermophilic sulfur cycling and underscore the need to consider the legacy of geologic and environmental change when describing processes that shape the assembly of communities. This article is protected by copyright. All rights reserved.

RevDate: 2019-08-09

Sutton KM, Lahmers KK, Harris SP, et al (2019)

Detection of Atypical Porcine Pestivirus Genome in Newborn Piglets Affected by Congenital Tremor and High Pre-weaning Mortality.

Journal of animal science pii:5545417 [Epub ahead of print].

Recently, piglets from a high-health status farm began exhibiting congenital tremors, high pre-weaning mortality and incidence of splayed legs. Postmortem histological examination identified a small number of scattered white matter vacuoles in the cerebellum and underlying brainstem of affected piglets. Presence of potential viral sources associated with this neurologic condition was initially infirmed using quantitative PCR (qPCR) for atypical porcine pestivirus (APPV), porcine teschovirus, and porcine sapelovirus. Using metagenomic analysis, APPV was identified as the main microbial species in serum obtained from piglets affected by congenital tremor. These piglets had higher pre-weaning mortality rates (46.4% vs 15.3%) and incidence of splayed legs (33.0 % vs 0.8 %) compared to unaffected piglets. Piglets affected by congenital tremor had higher viral titer (P < 0.15) and larger birth weights (P < 0.05) compared to normal litter-mates. Whole genome sequencing and genome assembly of the novel APPV strain (MK728876) was carried out using Oxford Nanopore and related bioinformatics pipelines. Phylogenic analysis demonstrated that this strain along with other completely sequenced APPV strains were grouped into two clades, both including strains inducing congenital tremor. Strains appear to cluster based on region but there were still significant differences within regions. Future research needs to address potential under-diagnosis due to genetic diversity but also to understand mode of transmission, variation in virulence, and the role of host genetics in APPV susceptibility.

RevDate: 2019-08-09

Lakin SM, Kuhnle A, Alipanahi B, et al (2019)

Hierarchical Hidden Markov models enable accurate and diverse detection of antimicrobial resistance sequences.

Communications biology, 2:294 pii:545.

The characterization of antimicrobial resistance genes from high-throughput sequencing data has become foundational in public health research and regulation. This requires mapping sequence reads to databases of known antimicrobial resistance genes to determine the genes present in the sample. Mapping sequence reads to known genes is traditionally accomplished using alignment. Alignment methods have high specificity but are limited in their ability to detect sequences that are divergent from the reference database, which can result in a substantial false negative rate. We address this shortcoming through the creation of Meta-MARC, which enables detection of diverse resistance sequences using hierarchical, DNA-based Hidden Markov Models. We first describe Meta-MARC and then demonstrate its efficacy on simulated and functional metagenomic datasets. Meta-MARC has higher sensitivity relative to competing methods. This sensitivity allows for detection of sequences that are divergent from known antimicrobial resistance genes. This functionality is imperative to expanding existing antimicrobial gene databases.

RevDate: 2019-08-09

Kauer RV, Koch MC, Hierweger MM, et al (2019)

Discovery of novel astrovirus genotype species in small ruminants.

PeerJ, 7:e7338 pii:7338.

Astroviruses (AstV) are single-stranded, positive-sense RNA viruses, best known for causing diarrhea in humans and are also found in many other mammals; in those, the relevance in gastroenteritis remains unclear. Recently described neurotropic AstV showed associations with encephalitis in humans as well as in other mammals. In Switzerland, two different neurotropic AstV were identified in cattle, as well as one in a sheep. The high genetic similarity between the ovine and one of the bovine AstV strengthens the hypothesis of an interspecies transmission. In humans, AstV associated with encephalitis were found also in human stool samples, suggesting that in these patients the infection spreads from the gastrointestinal tract to the brain under certain conditions, such as immunosuppression. Whether a similar pathogenesis occurs in ruminants remains unknown. The aims of this study were (1) the investigation of the potential occurrence of neurotropic AstV in feces samples, (2) the discovery and analysis of so far unknown AstV in small ruminants and other ruminant species' fecal samples and (3) the examination of a potential interspecies transmission of AstV. To achieve these aims, RNA extraction out of 164 fecal samples from different ruminant species was performed and all samples were screened for known neurotropic AstV occurring in Switzerland, as well as for various AstV using RT-PCR. Positive tested samples were submitted to next generation sequencing. The generated sequences were compared to nucleotide- and amino acid databases, virus properties were identified, and phylogenetic analyses as well as recombination analysis were performed. The excretion of neurotropic AstV in small ruminants' feces could not be demonstrated, but this work suggests the first identification of AstV in goats as well as the discovery of multiple and highly diverse new genetic variants in small ruminants, which lead to a classification into novel genotype-species. Additionally, the prediction of multiple recombination events in four of five newly discovered full or almost full-length genome sequences suggests a plausible interspecies transmission. The findings point out the occurrence and fecal shedding of previously unknown AstV in sheep and goats and pave the way towards a better understanding of the diversity and transmission of AstV in small ruminants.

RevDate: 2019-08-09

Ward LM, Cardona T, H Holland-Moritz (2019)

Evolutionary Implications of Anoxygenic Phototrophy in the Bacterial Phylum Candidatus Eremiobacterota (WPS-2).

Frontiers in microbiology, 10:1658.

Genome-resolved environmental metagenomic sequencing has uncovered substantial previously unrecognized microbial diversity relevant for understanding the ecology and evolution of the biosphere, providing a more nuanced view of the distribution and ecological significance of traits including phototrophy across diverse niches. Recently, the capacity for bacteriochlorophyll-based anoxygenic photosynthesis has been proposed in the uncultured bacterial WPS-2 phylum (recently proposed as Candidatus Eremiobacterota) that are in close association with boreal moss. Here, we use phylogenomic analysis to investigate the diversity and evolution of phototrophic WPS-2. We demonstrate that phototrophic WPS-2 show significant genetic and metabolic divergence from other phototrophic and non-phototrophic lineages. The genomes of these organisms encode a new family of anoxygenic Type II photochemical reaction centers and other phototrophy-related proteins that are both phylogenetically and structurally distinct from those found in previously described phototrophs. We propose the name Candidatus Baltobacterales for the order-level aerobic WPS-2 clade which contains phototrophic lineages, from the Greek for "bog" or "swamp," in reference to the typical habitat of phototrophic members of this clade.

RevDate: 2019-08-09

Guarino C, Zuzolo D, Marziano M, et al (2019)

Investigation and Assessment for an effective approach to the reclamation of Polycyclic Aromatic Hydrocarbon (PAHs) contaminated site: SIN Bagnoli, Italy.

Scientific reports, 9(1):11522 pii:10.1038/s41598-019-48005-7.

Native plant species were screened for their remediation potential for the removal of Polycyclic Aromatic Hydrocarbons (PAHs) contaminated soil of Bagnoli brownfield site (Southern Italy). Soils at this site contain all of the PAHs congeners at concentration levels well above the contamination threshold limits established by Italian environmental legislation for residential/recreational land use, which represent the remediation target. The concentration of 13 High Molecular Weight Polycyclic Aromatic Hydrocarbons in soil rhizosphere, plants roots and plants leaves was assessed in order to evaluate native plants suitability for a gentle remediation of the study area. Analysis of soil microorganisms are provides important knowledge about bioremediation approach. Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria are the main phyla of bacteria observed in polluted soil. Functional metagenomics showed changes in dioxygenases, laccase, protocatechuate, and benzoate-degrading enzyme genes. Indolacetic acid production, siderophores release, exopolysaccharides production and ammonia production are the key for the selection of the rhizosphere bacterial population. Our data demonstrated that the natural plant-bacteria partnership is the best strategy for the remediation of a PAHs-contaminated soil.

RevDate: 2019-08-09
CmpDate: 2019-08-09

Laitinen K, K Mokkala (2019)

Overall Dietary Quality Relates to Gut Microbiota Diversity and Abundance.

International journal of molecular sciences, 20(8): pii:ijms20081835.

Disturbances in gut microbiota homeostasis may have metabolic consequences with potentially serious clinical manifestations. Diet influences the host's metabolic health in several ways, either directly or indirectly by modulating the composition and function of gut microbiota. This study investigated the extent to which dietary quality is reflected in gut microbiota diversity in overweight and obese pregnant women at risk for metabolic complications. Dietary quality was measured by a validated index of diet quality (IDQ) and microbiota composition was analyzed using 16SrRNA gene sequencing from 84 women pregnant less than 18 weeks. The alpha diversity, measured as Chao1, observed operational taxonomic units (OTUs), phylogenetic diversity, and the Shannon index were calculated. The IDQ score correlated positively with the Shannon index (rho = 0.319, p = 0.003), but not with the other indexes. The women who had the highest dietary quality (highest IDQ quartile) had higher gut microbiota diversity in all the investigated indexes, when compared to the women with the lowest dietary quality (lowest IDQ quartile; p < 0.032). Consequently, a higher dietary quality was reflected in a higher gut microbiota diversity. The presented approach may aid in devising new tools for dietary counseling aiming at holistic health, as well as in microbiome studies, to control for dietary variance.

RevDate: 2019-08-08

Sánchez-Quinto A, LI Falcón (2019)

Metagenome of Acropora palmata coral rubble: Potential metabolic pathways and diversity in the reef ecosystem.

PloS one, 14(8):e0220117 pii:PONE-D-18-35292.

Over the past 30 years, the stony coral Acropora palmata has experienced an excessive loss of individuals showing few signs of recovery throughout the Mexican Caribbean, resulting in long stretches of coral rubble structures. When the coral dies, the skeleton begins to be colonized by algae, sponges, virus, bacteria and other microorganisms, forming a new community. Here we analyze, using a metagenomic approach, the diversity and biogeochemical cycles associated to coral rubble in La Bocana (Puerto Morelos, QRoo, Mexico). This study provides the first broad characterization of coral rubble associated communities and their role in biogeochemical cycling, suggesting a potential view of a world where coral reefs are no longer dominated by corals.

RevDate: 2019-08-08

Li G, Zhou Z, Yao L, et al (2019)

Full annotation of serum virome in Chinese blood donors with elevated alanine aminotransferase levels.

Transfusion [Epub ahead of print].

BACKGROUND: A serum alanine aminotransferase (ALT) test is currently demanded for blood donation in China. One of the major reasons to include such a test is possible etiology of known or unknown hepatotropic viruses. However, this hypothesis has never been examined convincingly.

STUDY DESIGN AND METHODS: The study recruited 90 Chinese blood donors that were divided into three groups based on their ALT values. Serum virome from these donors was explored using a metagenomics approach with enhanced sensitivity resolved at single sequencing reads.

RESULTS: Anellovirus and pegivirus C (GBV-C) were detected among these donors. None of them were found solely in donors with abnormal liver enzyme. Anellovirus was highly prevalent (93.3%) and the co-infection with multiple genera (alpha, beta, and gammatorquevirus) were more common in the donors with normal ALT values in comparison to those with elevated ALT (single/double/triple Anellovirus genera, 1/3/24 vs. 7/7/14 or 6/7/13, p = 0.009). For unmapped reads that accounted for 15 ± 14.9% of the data, similarity-based (BLASTN, BLASTP, and HMMER3) and similarity-independent (k-mer frequency) analysis identified several circular rep encoding ssDNA (CRESS-DNA) genomes. Direct PCR testing indicated these genomes were likely reagent contaminants.

CONCLUSION: Viral etiology is not responsible for elevated ALT levels in Chinese blood donors. The ALT test, if not abandoned, should be adjusted for its cutoff in response to donor shortage in China.

RevDate: 2019-08-08

Kori JA, Mahar RB, Vistro MR, et al (2019)

Metagenomic analysis of drinking water samples collected from treatment plants of Hyderabad City and Mehran University Employees Cooperative Housing Society.

Environmental science and pollution research international pii:10.1007/s11356-019-05859-8 [Epub ahead of print].

The quality assessment of water, supplied to the end user, is an essential part to assess the physical, chemical, and biological status of water, which impacts on human health. For the quality assessment of drinking water treatment plants and distribution systems of Hyderabad City and Mehran University of Engineering and Technology, Jamshoro, Pakistan, 13 surface drinking water samples were collected from three treatment plants, two of Hyderabad City, including WASA treatment plant and its distribution system (n = 5), Hala Nakka treatment plant and its distribution system (n = 6), and Mehran University Employees Cooperative Housing Society (MUECHS) treatment plant and its distribution system (n = 2). Physicochemical parameters of all drinking water samples were in the range compared to EPA and WHO guidelines, except in L-12 sample. Notably, no free-chlorine was detected in all samples. In metagenomics analysis, targeting V3-V4 hypervariable region of 16S rRNA gene, in QIIME2 environment, high bacterial prevalence was observed in all samples. On average, 348 OTUs were observed per sample. Among all samples, treated water sample from the Hala Nakka Treatment Plant (HNTR) was the most diverse sample in bacterial composition (Shannon 7.51 and Simpsons reciprocal indices 0.98). Overall, Proteobacteria, Bacteroidetes, Cyanobacteria, Verrucomicrobia, and Actinobacteria were the five most abundant phyla (relative abundances of 43.6, 37.9, 8.5, 2.5, and 2.4 percent, respectively). Notably, Cyanobacteria are well-known toxin producers which effect the human, and animal health. At genus level, Flavobacterium (4.86%) and Aquirestis (3.77%) were the most abundant genera. Functional predictions, based on 16S rRNA gene by PICRUSt, predicted 6909 KEGG orthologies, relating to 245 KEGG pathways. Among the predicted pathways of KEGG orthologies, pathways to human infections were also found. In conclusion, this study gave a deep insight into bacterial contamination in drinking water samples of Hyderabad City and MUECHS treatment plants and water quality status in Hyderabad and Mehran University of Engineering and Technology.

RevDate: 2019-08-08

Hovhannisyan H, Hafez A, Llorens C, et al (2019)

CROSSMAPPER: estimating cross-mapping rates and optimizing experimental design in multi-species sequencing studies.

Bioinformatics (Oxford, England) pii:5544929 [Epub ahead of print].

MOTIVATION: Numerous sequencing studies, including transcriptomics of host-pathogen systems, sequencing of hybrid genomes, xenografts, mixed species systems, metagenomics, and metatranscriptomics, involve samples containing genetic material from divergent organisms. A crucial step in these studies is identifying from which organism each sequencing read originated, and the experimental design should be directed to minimize biases caused by cross-mapping of reads to incorrect source genomes. Additionally, pooling of sufficiently different genetic material into a single sequencing library could significantly reduce experimental costs but requires careful planning and assessment of the impact of cross-mapping. Having these applications in mind we designed Crossmapper, the first to our knowledge tool able to assess cross-mapping prior to sequencing, therefore allowing optimization of experimental design.

RESULTS: Using any combination of reference genomes, Crossmapper performs read simulation and back-mapping of those reads to the pool of references, quantifies and reports the cross-mapping rates for each organism. Crossmapper performs these analyses with numerous user-specified parameters, including, among others, read length, read layout, coverage, mapping parameters, genomic or transcriptomic data. Additionally, it outputs the results in highly interactive and publication-ready reports. This allows the user to perform multiple comparisons at once and choose the experimental setup minimizing cross-mapping rates. Moreover, Crossmapper can be used for resource optimization in sequencing facilities by pooling different samples into one sequencing library.

AVAILABILITY: Crossmapper is a command line tool implemented in Python 3.6 and available as a conda package, allowing effortless installation. The source code, detailed information and a step-by-step tutorial is available at our GitHub page https://github.com/Gabaldonlab/crossmapper.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2019-08-08

Ai D, Pan H, Li X, et al (2019)

Association network analysis identifies enzymatic components of gut microbiota that significantly differ between colorectal cancer patients and healthy controls.

PeerJ, 7:e7315 pii:7315.

The human gut microbiota plays a major role in maintaining human health and was recently recognized as a promising target for disease prevention and treatment. Many diseases are traceable to microbiota dysbiosis, implicating altered gut microbial ecosystems, or, in many cases, disrupted microbial enzymes carrying out essential physio-biochemical reactions. Thus, the changes of essential microbial enzyme levels may predict human disorders. With the rapid development of high-throughput sequencing technologies, metagenomics analysis has emerged as an important method to explore the microbial communities in the human body, as well as their functionalities. In this study, we analyzed 156 gut metagenomics samples from patients with colorectal cancer (CRC) and adenoma, as well as that from healthy controls. We estimated the abundance of microbial enzymes using the HMP Unified Metabolic Analysis Network method and identified the differentially abundant enzymes between CRCs and controls. We constructed enzymatic association networks using the extended local similarity analysis algorithm. We identified CRC-associated enzymic changes by analyzing the topological features of the enzymatic association networks, including the clustering coefficient, the betweenness centrality, and the closeness centrality of network nodes. The network topology of enzymatic association network exhibited a difference between the healthy and the CRC environments. The ABC (ATP binding cassette) transporter and small subunit ribosomal protein S19 enzymes, had the highest clustering coefficient in the healthy enzymatic networks. In contrast, the Adenosylhomocysteinase enzyme had the highest clustering coefficient in the CRC enzymatic networks. These enzymic and metabolic differences may serve as risk predictors for CRCs and are worthy of further research.

RevDate: 2019-08-08
CmpDate: 2019-08-08

Zhang H, Yohe T, Huang L, et al (2018)

dbCAN2: a meta server for automated carbohydrate-active enzyme annotation.

Nucleic acids research, 46(W1):W95-W101.

Complex carbohydrates of plants are the main food sources of animals and microbes, and serve as promising renewable feedstock for biofuel and biomaterial production. Carbohydrate active enzymes (CAZymes) are the most important enzymes for complex carbohydrate metabolism. With an increasing number of plant and plant-associated microbial genomes and metagenomes being sequenced, there is an urgent need of automatic tools for genomic data mining of CAZymes. We developed the dbCAN web server in 2012 to provide a public service for automated CAZyme annotation for newly sequenced genomes. Here, dbCAN2 (http://cys.bios.niu.edu/dbCAN2) is presented as an updated meta server, which integrates three state-of-the-art tools for CAZome (all CAZymes of a genome) annotation: (i) HMMER search against the dbCAN HMM (hidden Markov model) database; (ii) DIAMOND search against the CAZy pre-annotated CAZyme sequence database and (iii) Hotpep search against the conserved CAZyme short peptide database. Combining the three outputs and removing CAZymes found by only one tool can significantly improve the CAZome annotation accuracy. In addition, dbCAN2 now also accepts nucleotide sequence submission, and offers the service to predict physically linked CAZyme gene clusters (CGCs), which will be a very useful online tool for identifying putative polysaccharide utilization loci (PULs) in microbial genomes or metagenomes.

RevDate: 2019-08-07

Agyirifo DS, Wamalwa M, Otwe EP, et al (2019)

Metagenomics analysis of cocoa bean fermentation microbiome identifying species diversity and putative functional capabilities.

Heliyon, 5(7):e02170 pii:e02170.

Fermentation of Theobroma cacao L. beans is the most critical stage in the production of cocoa products such as chocolates and its derivatives. There is a limited understanding of the complex response of microbial diversity during cocoa bean fermentation. The aim of the present study was to investigate microbial communities in the cocoa bean fermentation heap using a culture-independent approach to elucidate microbial diversity, structure, functional annotation and mapping unto metabolic pathways. Genomic DNA was extracted and purified from a sample of cocoa beans fermentation heap and was followed by library preparations. Sequence data was generated on Illumina Hiseq 2000 paired-end technology (Macrogen Inc). Taxonomic analysis based on genes predicted from the metagenome identified a high percentage of Bacteria (90.0%), Yeast (9%), and bacteriophages (1%) from the cocoa microbiome. Lactobacillus (20%), Gluconacetobacter (9%), Acetobacter (7%) and Gluconobacter (6%) dominated this study. The mean species diversity, measured by Shannon alpha-diversity index, was estimated at 142.81. Assignment of metagenomic sequences to SEED database categories at 97% sequence similarity identified a genetic profile characteristic of heterotrophic lactic acid fermentation of carbohydrates and aromatic amino acids. Metabolism of aromatic compounds, amino acids and their derivatives and carbohydrates occupied 0.6%, 8% and 13% respectively. Overall, these results provide insights into the cocoa microbiome, identifying fermentation processes carried out broadly by complex microbial communities and metabolic pathways encoding aromatic compounds such as phenylacetaldehyde, butanediol, acetoin, and theobromine that are required for flavour and aroma production. The results obtained will help develop targeted inoculations to produce desired chocolate flavour or targeted metabolic pathways for the selection of microbes for good aroma and flavour compounds formation.

RevDate: 2019-08-07

Kang DD, Li F, Kirton E, et al (2019)

MetaBAT 2: an adaptive binning algorithm for robust and efficient genome reconstruction from metagenome assemblies.

PeerJ, 7:e7359 pii:7359.

We previously reported on MetaBAT, an automated metagenome binning software tool to reconstruct single genomes from microbial communities for subsequent analyses of uncultivated microbial species. MetaBAT has become one of the most popular binning tools largely due to its computational efficiency and ease of use, especially in binning experiments with a large number of samples and a large assembly. MetaBAT requires users to choose parameters to fine-tune its sensitivity and specificity. If those parameters are not chosen properly, binning accuracy can suffer, especially on assemblies of poor quality. Here, we developed MetaBAT 2 to overcome this problem. MetaBAT 2 uses a new adaptive binning algorithm to eliminate manual parameter tuning. We also performed extensive software engineering optimization to increase both computational and memory efficiency. Comparing MetaBAT 2 to alternative software tools on over 100 real world metagenome assemblies shows superior accuracy and computing speed. Binning a typical metagenome assembly takes only a few minutes on a single commodity workstation. We therefore recommend the community adopts MetaBAT 2 for their metagenome binning experiments. MetaBAT 2 is open source software and available at https://bitbucket.org/berkeleylab/metabat.

RevDate: 2019-08-07

Ziels RM, Nobu MK, DZ Sousa (2019)

Elucidating Syntrophic Butyrate-Degrading Populations in Anaerobic Digesters Using Stable-Isotope-Informed Genome-Resolved Metagenomics.

mSystems, 4(4): pii:4/4/e00159-19.

Linking the genomic content of uncultivated microbes to their metabolic functions remains a critical challenge in microbial ecology. Resolving this challenge has implications for improving our management of key microbial interactions in biotechnologies such as anaerobic digestion, which relies on slow-growing syntrophic and methanogenic communities to produce renewable methane from organic waste. In this study, we combined DNA stable-isotope probing (SIP) with genome-centric metagenomics to recover the genomes of populations enriched in 13C after growing on [13C]butyrate. Differential abundance analysis of recovered genomic bins across the SIP metagenomes identified two metagenome-assembled genomes (MAGs) that were significantly enriched in heavy [13C]DNA. Phylogenomic analysis assigned one MAG to the genus Syntrophomonas and the other MAG to the genus Methanothrix. Metabolic reconstruction of the annotated genomes showed that the Syntrophomonas genome encoded all the enzymes for beta-oxidizing butyrate, as well as several mechanisms for interspecies electron transfer via electron transfer flavoproteins, hydrogenases, and formate dehydrogenases. The Syntrophomonas genome shared low average nucleotide identity (<95%) with any cultured representative species, indicating that it is a novel species that plays a significant role in syntrophic butyrate degradation within anaerobic digesters. The Methanothrix genome contained the complete pathway for acetoclastic methanogenesis, indicating that it was enriched in 13C from syntrophic acetate transfer. This study demonstrates the potential of stable-isotope-informed genome-resolved metagenomics to identify in situ interspecies metabolic cooperation within syntrophic consortia important to anaerobic waste treatment as well as global carbon cycling.IMPORTANCE Predicting the metabolic potential and ecophysiology of mixed microbial communities remains a major challenge, especially for slow-growing anaerobes that are difficult to isolate. Unraveling the in situ metabolic activities of uncultured species may enable a more descriptive framework to model substrate transformations by microbiomes, which has broad implications for advancing the fields of biotechnology, global biogeochemistry, and human health. Here, we investigated the in situ function of mixed microbiomes by combining stable-isotope probing with metagenomics to identify the genomes of active syntrophic populations converting butyrate, a C4 fatty acid, into methane within anaerobic digesters. This approach thus moves beyond the mere presence of metabolic genes to resolve "who is doing what" by obtaining confirmatory assimilation of the labeled substrate into the DNA signature. Our findings provide a framework to further link the genomic identities of uncultured microbes with their ecological function within microbiomes driving many important biotechnological and global processes.

RevDate: 2019-08-07

Joseph SM, Battaglia T, Maritz JM, et al (2019)

Longitudinal Comparison of Bacterial Diversity and Antibiotic Resistance Genes in New York City Sewage.

mSystems, 4(4): pii:4/4/e00327-19.

Bacterial resistance to antibiotics is a pressing health issue around the world, not only in health care settings but also in the community and environment, particularly in crowded urban populations. The aim of our work was to characterize the microbial populations in sewage and the spread of antibiotic resistance within New York City (NYC). Here, we investigated the structure of the microbiome and the prevalence of antibiotic resistance genes in raw sewage samples collected from the fourteen NYC Department of Environmental Protection wastewater treatment plants, distributed across the five NYC boroughs. Sewage, a direct output of anthropogenic activity and a reservoir of microbes, provides an ecological niche to examine the spread of antibiotic resistance. Taxonomic diversity analysis revealed a largely similar and stable bacterial population structure across all the samples, which was found to be similar over three time points in an annual cycle, as well as in the five NYC boroughs. All samples were positive for the presence of the seven antibiotic resistance genes tested, based on real-time quantitative PCR assays, with higher levels observed for tetracycline resistance genes at all time points. For five of the seven genes, abundances were significantly higher in May than in February and August. This study provides characteristics of the NYC sewage resistome in the context of the overall bacterial populations.IMPORTANCE Urban sewage or wastewater is a diverse source of bacterial growth, as well as a hot spot for the development of environmental antibiotic resistance, which can in turn influence the health of the residents of the city. As part of a larger study to characterize the urban New York City microbial metagenome, we collected raw sewage samples representing three seasonal time points spanning the five boroughs of NYC and went on to characterize the microbiome and the presence of a range of antibiotic resistance genes. Through this study, we have established a baseline microbial population and antibiotic resistance abundance in NYC sewage which can prove to be very useful in studying the load of antibiotic usage, as well as for developing effective measures in antibiotic stewardship.

RevDate: 2019-08-07

Zhu Z, Ren J, Michail S, et al (2019)

MicroPro: using metagenomic unmapped reads to provide insights into human microbiota and disease associations.

Genome biology, 20(1):154 pii:10.1186/s13059-019-1773-5.

We develop a metagenomic data analysis pipeline, MicroPro, that takes into account all reads from known and unknown microbial organisms and associates viruses with complex diseases. We utilize MicroPro to analyze four metagenomic datasets relating to colorectal cancer, type 2 diabetes, and liver cirrhosis and show that including reads from unknown organisms significantly increases the prediction accuracy of the disease status for three of the four datasets. We identify new microbial organisms associated with these diseases and show viruses play important prediction roles in colorectal cancer and liver cirrhosis, but not in type 2 diabetes. MicroPro is freely available at https://github.com/zifanzhu/MicroPro .

RevDate: 2019-08-07

Qi K, Men X, Wu J, et al (2019)

Rearing pattern alters porcine myofiber type, fat deposition, associated microbial communities and functional capacity.

BMC microbiology, 19(1):181 pii:10.1186/s12866-019-1556-x.

BACKGROUND: The Chinese believe that the meat of pigs reared in the past with free range tastes better than that of the pigs reared indoor on a large scale today. Gastrointestinal microflora is closely associated with the main factor of meat flavour, including fibre characteristics and lipid metabolism. Our method in this study involved different raising patterns within the semi free-grazing farm (FF) or indoor feeding farm (DF), the measurement of fat deposition and myofiber type by paraffin section and reverse transcription polymerase chain reaction and the identification of microbiome and functional capacities associated with meat quality through metagenomic sequencing.

RESULTS: Results showed that the fat area in muscle and adipose tissue and the myofiber density significantly increased in the pigs of the FF group. The relative abundance of bacteria associated with lipid metabolism, such as g_Oscillibacter, in the feces of the FF group was higher than that in DF group, and the relative abundance of some bacteria with probiotic function, including g_Lactobacillus and g_Clostridium, was lower than that in DF group. The abundance of g_Clostridium was significantly positively correlated with the intramuscular fat area, whereas health-related bacteria, such as g_Butyricicoccus, g_Eubacterium, g_Phascolarctobacterium and g_Oribacterium, was significantly negatively correlated with abdominal fat area, myofiber density and adipose triglyceride lipase (ATGL) mRNA expression. KEGG analysis showed that pigs raised in semi free-grazing farm can activate the pathway of inosine monophosphate (IMP) biosynthesis, glycolysis/gluconeogenesis and alanine, aspartate and glutamate metabolism.

CONCLUSIONS: Free range feeding improves meat quality by changing the fibre type, myofiber density and metabolic pathways related to flavour amino acids, IMP or glycolysis/gluconeogenesis in muscle. However, prolonged feeding cycle increases fat deposition and associated microbial communities.

RevDate: 2019-08-06

Fishman JA (2019)

Infection in xenotransplantation: opportunities and challenges.

Current opinion in organ transplantation [Epub ahead of print].

PURPOSE OF REVIEW: Posttransplantation infections are common. It is anticipated that infection will be no less common in xenotransplantation recipients. Prolonged xenograft survivals have resulted from advances in immunosuppressive strategies and development of swine that decrease host immune responses via genetic manipulation, notably CRISPR/cas9 manipulation. As prospects for clinical trials improve, consideration of the unique infectious risks posed by xenotransplantation reemerge.

RECENT FINDINGS: Organisms likely to cause infection in human recipients of porcine xenografts are unknown in advance of clinical trials. Microbiological screening of swine intended as xenograft donors can be more intensive than is currently feasible for human allograft donors. Monitoring infection in recipients will also be more intensive. Key opportunities in infectious diseases of xenotransplantation include major technological advances in evaluation of the microbiome by unbiased metagenomic sequencing, assessments of some risks posed by porcine endogenous retroviruses (PERVs) including antiretroviral susceptibilities, availability of swine with deletion of genomic PERVs, and recognition of the rapidly changing epidemiology of infection in swine worldwide.

SUMMARY: Unknown infectious risks in xenotransplantation requires application of advanced microbiological techniques to discern and prevent infection in graft recipients. Clinical trials will provide an opportunity to advance the safety of all of organ transplantation.

RevDate: 2019-08-06

Ellilä S, Bromann P, Nyyssönen M, et al (2019)

Cloning of novel bacterial xylanases from lignocellulose-enriched compost metagenomic libraries.

AMB Express, 9(1):124 pii:10.1186/s13568-019-0847-9.

Xylanases are in important class of industrial enzymes that are essential for the complete hydrolysis of lignocellulosic biomass into fermentable sugars. In the present study, we report the cloning of novel xylanases with interesting properties from compost metagenomics libraries. Controlled composting of lignocellulosic materials was used to enrich the microbial population in lignocellulolytic organisms. DNA extracted from the compost samples was used to construct metagenomics libraries, which were screened for xylanase activity. In total, 40 clones exhibiting xylanase activity were identified and the thermostability of the discovered xylanases was assayed directly from the library clones. Five genes, including one belonging to the more rare family GH8, were selected for subcloning and the enzymes were expressed in recombinant form in E. coli. Preliminary characterization of the metagenome-derived xylanases revealed interesting properties of the novel enzymes, such as high thermostability and specific activity, and differences in hydrolysis profiles. One enzyme was found to perform better than a standard Trichoderma reesei xylanase in the hydrolysis of lignocellulose at elevated temperatures.

RevDate: 2019-08-06

Brun P (2019)

The profiles of dysbiotic microbial communities.

AIMS microbiology, 5(1):87-101 pii:microbiol-05-01-087.

Alterations in the human gut microbiota play an important role in disease pathogenesis. Although next-generation sequencing has provided observational evidence linking shifts in gut microbiota composition to alterations in the human host, underlying mechanisms remain elusive. Metabolites generated within complex microbial communities and at the crossroads with host cells may be able to explain the impact of the gut microbiome on human homeostasis. Emerging technologies including novel culturing protocols, microfluidic systems, engineered organoids, and single-cell imaging approaches are providing new perspectives from which the gut microbiome can be studied paving the way to new diagnostic markers and personalized therapeutic interventions.

RevDate: 2019-08-06

MacLeod F, Kindler GS, Wong HL, et al (2019)

Asgard archaea: Diversity, function, and evolutionary implications in a range of microbiomes.

AIMS microbiology, 5(1):48-61 pii:microbiol-05-01-048.

Elucidating the diversity of the Archaea has many important ecological and evolutionary implications. The Asgard superphylum of the archaea, described recently from metagenomic data, has reignited the decades-old debate surrounding the topology of the tree of life. This review synthesizes recent findings through publicly available genomes and literature to describe the current ecological and evolutionary significance of the Asgard superphylum. Asgard archaea have been found in a diverse range of microbiomes across the globe, primarily from sedimentary environments. Within these environments, positive correlations between specific members of the Asgard archaea and Candidate Division TA06 bacteria have been observed, opening up the possibility of symbiotic interactions between the groupings. Asgard archaeal genomes encode functionally diverse metabolic pathways, including the Wood-Ljungdahl pathway as a carbon-fixation strategy, putative nucleotide salvaging pathways, and novel mechanisms of phototrophy including new rhodopsins. Asgard archaea also appear to be active in nitrogen cycling. Asgard archaea encode genes involved in both dissimilatory nitrate reduction and denitrification, and for the potential to use atmospheric nitrogen or nitrite as nitrogen sources. Asgard archaea also may be involved in the transformation of sulfur compounds, indicating a putative role in sulfur cycling. To date, all Asgard archaeal genomes identified were described as obligately anaerobic. The Asgard archaea also appear to have important evolutionary implications. The presence of eukaryotic signature proteins and the affiliation of Asgard archaea in phylogenetic analyses appears to support two-domain topologies of the tree of life with eukaryotes emerging from within the domain of archaea, as opposed to the eukaryotes being a separate domain of life. Thus far, Heimdallarchaeota appears as the closest archaeal relative of eukaryotes.

RevDate: 2019-08-06

Krystel J, Shi Q, Shaw J, et al (2019)

An in vitro protocol for rapidly assessing the effects of antimicrobial compounds on the unculturable bacterial plant pathogen, Candidatus Liberibacter asiaticus.

Plant methods, 15:85 pii:465.

Background: Most bacteria are not culturable, but can be identified through molecular methods such as metagenomics studies. Due to specific metabolic requirements and symbiotic relationships, these bacteria cannot survive on typical laboratory media. Many economically and medically important bacteria are unculturable; including phloem-limited plant pathogens like Candidatus Liberibacter asiaticus (CLas). CLas is the most impactful pathogen on citrus production, is vectored by the Asian citrus psyllid (ACP, Diaphorina citri), and lacks an effective treatment or resistant cultivars. Research into CLas pathogenicity and therapy has been hindered by the lack of persistent pure cultures. Work to date has been mostly limited to in planta studies that are time and resource intensive.

Results: We developed and optimized an in vitro protocol to quickly test the effectiveness of potential therapeutic agents against CLas. The assay uses intact bacterial cells contained in homogenized tissue from CLas-infected ACP and a propidium monoazide (PMA) assay to measure antimicrobial activity. The applicability of PMA was evaluated; with the ability to differentiate between intact and disrupted CLas cells confirmed using multiple bactericidal treatments. We identified light activation conditions to prevent PCR interference and identified a suitable positive control for nearly complete CLas disruption (0.1% Triton-X 100). Isolation buffer components were optimized with 72 mM salt mixture, 1 mM phosphate buffer and 1% glycerol serving to minimize unwanted interactions with treatment and PMA chemistries and to maximize recovery of intact CLas cells. The mature protocol was used to compare a panel of peptides already under study for potential CLas targeting bactericidal activity and identify which were most effective.

Conclusion: This psyllid homogenate assay allows for a quick assessment of potential CLas-disrupting peptides. Comparison within a uniform isolate largely eliminates experimental error arising from variation in CLas titer between and within individual host organisms. Use of an intact vs. disrupted assay permits direct assessment of potential therapeutic compounds without generating pure cultures or conducting extensive in planta or field studies.

RevDate: 2019-08-06

Mitchell SL, PJ Simner (2019)

Next-Generation Sequencing in Clinical Microbiology: Are We There Yet?.

Clinics in laboratory medicine, 39(3):405-418.

Next-generation sequencing (NGS) applications have been transitioning from research tools to diagnostic methods and are becoming more commonplace in clinical microbiology laboratories. These applications include (1) whole-genome sequencing, (2) targeted next-generation sequencing methods, and (3) metagenomic next-generation sequencing. The introduction of these methods into the clinical microbiology laboratory has led to the theoretic question of "Will NGS-based methods supplant traditional methods for strain typing, identification, and antimicrobial susceptibility prediction?" The authors address this question and discuss where we are at now with clinical NGS applications for infectious diseases, what does the future hold, and at what cost?

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ESP Quick Facts

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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.

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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
21454 NE 143rd Street
Woodinville, WA 98077

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 )