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Bibliography on: Biodiversity and Metagenomics

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ESP: PubMed Auto Bibliography 17 Sep 2021 at 01:30 Created: 

Biodiversity and Metagenomics

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

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

Citations The Papers (from PubMed®)

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RevDate: 2021-09-15

Guan H, Pu Y, Liu C, et al (2021)

Comparison of Fecal Collection Methods on Variation in Gut Metagenomics and Untargeted Metabolomics.

mSphere [Epub ahead of print].

Integrative analysis of high-quality metagenomics and metabolomics data from fecal samples provides novel clues for the mechanism underpinning gut microbe-human interactions. However, data regarding the influence of fecal collection methods on both metagenomics and metabolomics are sparse. Six fecal collection methods (the gold standard [GS] [i.e., immediate freezing at -80°C with no solution], 95% ethanol, RNAlater, OMNIgene Gut, fecal occult blood test [FOBT] cards, and Microlution) were used to collect 88 fecal samples from eight healthy volunteers for whole-genome shotgun sequencing (WGSS) and untargeted metabolomic profiling. Metrics assessed included the abundances of predominant phyla and α- and β-diversity at the species, gene, and pathway levels. Intraclass correlation coefficients (ICCs) were calculated for microbes and metabolites to estimate (i) stability (day 4 versus day 0 within each method), (ii) concordance (day 0 for each method versus the GS), and (iii) reliability (day 4 for each method versus the GS). For the top 4 phyla and microbial diversity metrics at the species, gene, and pathway levels, generally high stability and reliability were observed for most methods except for 95% ethanol; similar concordances were seen for different methods. For metabolomics data, 95% ethanol showed the highest stability, concordance, and reliability (median ICCs = 0.71, 0.71, and 0.65, respectively). Taken together, OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles. We recommend using separate collecting methods for gut metagenomic sequencing and fecal metabolomic profiling in large population studies. IMPORTANCE The choice of fecal collection method is essential for studying gut microbe-human interactions in large-scale population-based research. In this study, we examined the effects of fecal collection methods and storage time at ambient temperature on variations in the gut microbiome community composition; microbial diversity metrics at the species, gene, and pathway levels; antibiotic resistance genes; and metabolome profiling. Our findings suggest using different fecal sample collection methods for different data generation purposes. OMNIgene Gut, FOBT cards, RNAlater, and Microlution, but not 95% ethanol, were reliable collection methods for gut metagenomic studies. However, 95% ethanol was the best for preserving fecal metabolite profiles.

RevDate: 2021-09-15
CmpDate: 2021-09-15

Fu X, Ou Z, Zhang M, et al (2021)

Classroom microbiome, functional pathways and sick-building syndrome (SBS) in urban and rural schools - Potential roles of indoor microbial amino acids and vitamin metabolites.

The Science of the total environment, 795:148879.

Sick building symptoms (SBS) are defined as non-specific symptoms related to indoor exposures, including mucosal symptoms in eye, nose, throat, and skin, and general symptoms as headache and tiredness. Indoor microbial composition is associated with SBS symptoms, but the impact of microbial functional genes and potential metabolic products has not been characterized. We conducted a shotgun microbial metagenomic sequencing for vacuum dust collected in urban and rural schools in Shanxi province, China. SBS symptoms in students were surveyed, and microbial taxa and functional pathways related to the symptoms were identified using a multi-level linear regression model. SBS symptoms were common in students, and the prevalence of ocular and throat symptoms, headache, and tiredness was higher in urban than in rural areas (p < 0.05). A significant higher microbial α-diversity was found in rural areas than in urban areas (Chao1, p = 0.001; ACE, p = 0.002). Also, significant variation in microbial taxonomic and functional composition (β-diversity) was observed between urban and rural areas (p < 0.005). Five potential risk Actinobacteria species were associated with SBS symptoms (p < 0.01); students in the classrooms with a higher abundance of an unclassified Geodermatophilaceae, Geodermatophilus, Fridmanniella luteola, Microlunatus phosphovorus and Mycetocola reported more nasal and throat symptoms and tiredness. Students with a higher abundance of an unclassified flavobacteriaceae reported fewer throat symptoms and tiredness. The abundance of microbial metabolic pathways related to the synthesis of B vitamins (biotin and folate), gamma-aminobutyric acid (GABA), short-chain fatty acids (SCFAs), and peptidoglycan and were protectively (negatively) associated with SBS symptoms (FDR < 0.05). The result is consistent with human microbiota studies, which reported that these microbial products are extensively involved in immunological processes and anti-inflammatory effects. This is the first study to report the functional potential of the indoor microbiome and the occurrence of SBS, providing new insights into the potential etiologic mechanisms in chronic inflammatory diseases.

RevDate: 2021-09-15
CmpDate: 2021-09-15

Wippel K, Tao K, Niu Y, et al (2021)

Host preference and invasiveness of commensal bacteria in the Lotus and Arabidopsis root microbiota.

Nature microbiology, 6(9):1150-1162.

Roots of different plant species are colonized by bacterial communities, that are distinct even when hosts share the same habitat. It remains unclear to what extent the host actively selects these communities and whether commensals are adapted to a specific plant species. To address this question, we assembled a sequence-indexed bacterial culture collection from roots and nodules of Lotus japonicus that contains representatives of most species previously identified using metagenomics. We analysed taxonomically paired synthetic communities from L. japonicus and Arabidopsis thaliana in a multi-species gnotobiotic system and detected signatures of host preference among commensal bacteria in a community context, but not in mono-associations. Sequential inoculation experiments revealed priority effects during root microbiota assembly, where established communities are resilient to invasion by latecomers, and that host preference of commensal bacteria confers a competitive advantage in their cognate host. Our findings show that host preference in commensal bacteria from diverse taxonomic groups is associated with their invasiveness into standing root-associated communities.

RevDate: 2021-09-15
CmpDate: 2021-09-15

Hewson I, MA Sewell (2021)

Surveillance of densoviruses and mesomycetozoans inhabiting grossly normal tissues of three Aotearoa New Zealand asteroid species.

PloS one, 16(4):e0241026.

Asteroid wasting events and mass mortality have occurred for over a century. We currently lack a fundamental understanding of the microbial ecology of asteroid disease, with disease investigations hindered by sparse information about the microorganisms associated with grossly normal specimens. We surveilled viruses and protists associated with grossly normal specimens of three asteroid species (Patiriella regularis, Stichaster australis, Coscinasterias muricata) on the North Island / Te Ika-a-Māui, Aotearoa New Zealand, using metagenomes prepared from virus and ribosome-sized material. We discovered several densovirus-like genome fragments in our RNA and DNA metagenomic libraries. Subsequent survey of their prevalence within populations by quantitative PCR (qPCR) demonstrated their occurrence in only a few (13%) specimens (n = 36). Survey of large and small subunit rRNAs in metagenomes revealed the presence of a mesomycete (most closely matching Ichthyosporea sp.). Survey of large subunit prevalence and load by qPCR revealed that it is widely detectable (80%) and present predominately in body wall tissues across all 3 species of asteroid. Our results raise interesting questions about the roles of these microbiome constituents in host ecology and pathogenesis under changing ocean conditions.

RevDate: 2021-09-15
CmpDate: 2021-09-15

Dizzell S, Stearns JC, Li J, et al (2021)

Investigating colonization patterns of the infant gut microbiome during the introduction of solid food and weaning from breastmilk: A cohort study protocol.

PloS one, 16(4):e0248924.

The first exposures to microbes occur during infancy and it is suggested that this initial colonization influences the adult microbiota composition. Despite the important role that the gut microbiome may have in health outcomes later in life, the factors that influence its development during infancy and early childhood have not been characterized fully. Guidelines about the introduction of solid foods and cessation of breastfeeding, which is thought to have a significant role in the transition to a more adult-like microbiota, are not based on microbiome research. There is even less understanding of approaches used to transition to solid food in the preterm population. The purpose of this study is to identify the impact of early life dietary events on gut microbiome community structures and function among infants born at term and pre-term. We plan to prospectively monitor the gut microbiome of infants during two critical timepoints in microbial development: the introduction of solid foods and cessation from breastmilk. A total of 35 participants from three primary observational birth cohorts (two full-term cohorts and one pre-term cohort) will be enrolled in this sub-study. Participants will be asked to collect stool samples and fill out a study diary before, during and after the introduction of solids and again during weaning from breastmilk. We will use frequent fecal sampling analyzed using 16S rRNA gene profiling, metagenomics, metabolomics, and targeted bacterial culturing to identify and characterize the microbial communities, as well as provide insight into the phenotypic characteristics and functional capabilities of the microbes present during these transitional periods of infancy. This study will provide a comprehensive approach to detailing the effects of dietary transition from breastmilk to a more adult-like solid food diet on the microbiome and in doing so will contribute to evidence-based infant nutrition guidance.

RevDate: 2021-09-14
CmpDate: 2021-09-14

Li W, Gao J, Zhuang JL, et al (2021)

Metagenomics and metatranscriptomics uncover the microbial community associated with high S0 production in a denitrifying desulfurization granular sludge reactor.

Water research, 203:117505.

The denitrification desulfurization process is a promising technology for elemental sulfur (S0) production from sulfide containing wastewater. However, the microbial community associated with high S0 production still is not well studied. This study describes an efficient denitrification S0 production bioreactor based on inoculation with anaerobic granular sludge. At an optimal S/N molar ratio of 7:2, 80 % of the influent sulfide was transformed to high quality elemental sulfur with a purity of 92.5% while the total inorganic nitrogen removal efficiency was stable at ∼80%. Metatranscriptomic analysis found that community expression of the gene encoding the sulfide-quinone reductase (SQR) was 10-fold greater than that of the flavocytochrome-c sulfide dehydrogenase subunit B (fccB). Moreover, the expression level of SQR was also significantly higher than the Dsr gene encoding for dissimilatory sulfate reductase, which encodes a critical S0 oxidation enzyme. Metagenomic binning analysis confirmed that sulfide-oxidizing bacteria (SOB) utilizing SQR were common in the community and most likely accounted for high S0 production. An unexpected enrichment in methanogens and high expression activity of bacteria carrying out Stickland fermentation as well as in other bacteria with reduced genomes indicated a complex community supporting stable sulfide oxidation to S0, likely aiding in performance stability. This study establishes this treatment approach as an alternative biotechnology for sulfide containing wastewater treatment and sheds light on the microbial interactions associated with high S0 production.

RevDate: 2021-09-14
CmpDate: 2021-09-14

Pan Y, Zheng X, Y Xiang (2021)

Structure-function elucidation of a microbial consortium in degrading rice straw and producing acetic and butyric acids via metagenome combining 16S rDNA sequencing.

Bioresource technology, 340:125709.

The characterized microbial consortium can efficiently degrade rice straw to produce acetic and butyric acids in high yields. The rice straw lost 86.9% in weight and degradation rates of hemicellulose, cellulose, and lignin attained were 97.1%, 86.4% and 70.3% within 12 days, respectively. During biodegradation via fermentation of rice straw, average concentrations of acetic and butyric acids reached 1570 mg/L and 1270 mg/L, accounting for 47.2% and 35.4% of the total volatile fatty acids, respectively. The consortium mainly composed of Prevotella, Cellulosilyticum, Pseudomonas, Clostridium and Ruminococcaceae, etc. Metagenomic analyses indicated that glycoside hydrolases (GHs) were the largest enzyme group with a relative abundance of 54.5%. Various lignocellulose degrading enzymes were identified in the top 30 abundant GHs, and were primarily distributed in the dominant genera (Prevotella, Cellulosilyticum and Clostridium). These results provide a new route for the commercial recycling of rice straw to produce organic acids.

RevDate: 2021-09-14
CmpDate: 2021-09-14

Pérez-Sáez MJ, Uffing A, Leon J, et al (2021)

Immunological Impact of a Gluten-Free Dairy-Free Diet in Children With Kidney Disease: A Feasibility Study.

Frontiers in immunology, 12:624821.

Kidney disease affects 10% of the world population and is associated with increased mortality. Steroid-resistant nephrotic syndrome (SRNS) is a leading cause of end-stage kidney disease in children, often failing standard immunosuppression. Here, we report the results of a prospective study to investigate the immunological impact and safety of a gluten-free and dairy-free (GF/DF) diet in children with SRNS. The study was organized as a four-week summer camp implementing a strict GF/DF diet with prospective collection of blood, urine and stool in addition to whole exome sequencing WES of DNA of participants. Using flow cytometry, proteomic assays and microbiome metagenomics, we show that GF/DF diet had a major anti-inflammatory effect in all participants both at the protein and cellular level with 4-fold increase in T regulatory/T helper 17 cells ratio and the promotion of a favorable regulatory gut microbiota. Overall, GF/DF can have a significant anti-inflammatory effect in children with SRNS and further trials are warranted to investigate this potential dietary intervention in children with SRNS.

RevDate: 2021-09-14
CmpDate: 2021-09-14

Raiyani NM, SP Singh (2020)

Taxonomic and functional profiling of the microbial communities of Arabian Sea: A metagenomics approach.

Genomics, 112(6):4361-4369.

RevDate: 2021-09-13

Liu Y, Zheng K, Liu B, et al (2021)

Characterization and Genomic Analysis of Marinobacter Phage vB_MalS-PS3, Representing a New Lambda-Like Temperate Siphoviral Genus Infecting Algae-Associated Bacteria.

Frontiers in microbiology, 12:726074.

Marinobacter is the abundant and important algal-associated and hydrocarbon biodegradation bacteria in the ocean. However, little knowledge about their phages has been reported. Here, a novel siphovirus, vB_MalS-PS3, infecting Marinobacter algicola DG893(T), was isolated from the surface waters of the western Pacific Ocean. Transmission electron microscopy (TEM) indicated that vB_MalS-PS3 has the morphology of siphoviruses. VB_MalS-PS3 was stable from -20 to 55°C, and with the latent and rise periods of about 80 and 10 min, respectively. The genome sequence of VB_MalS-PS3 contains a linear, double-strand 42,168-bp DNA molecule with a G + C content of 56.23% and 54 putative open reading frames (ORFs). Nineteen conserved domains were predicted by BLASTp in NCBI. We found that vB_MalS-PS3 represent an understudied viral group with only one known isolate. The phylogenetic tree based on the amino acid sequences of whole genomes revealed that vB_MalS-PS3 has a distant evolutionary relationship with other siphoviruses, and can be grouped into a novel viral genus cluster with six uncultured assembled viral genomes from metagenomics, named here as Marinovirus. This study of the Marinobacter phage vB_MalS-PS3 genome enriched the genetic database of marine bacteriophages, in addition, will provide useful information for further research on the interaction between Marinobacter phages and their hosts, and their relationship with algal blooms and hydrocarbon biodegradation in the ocean.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Mehta S, Crane M, Leith E, et al (2021)

ASaiM-MT: a validated and optimized ASaiM workflow for metatranscriptomics analysis within Galaxy framework.

F1000Research, 10:103.

The Earth Microbiome Project (EMP) aided in understanding the role of microbial communities and the influence of collective genetic material (the 'microbiome') and microbial diversity patterns across the habitats of our planet. With the evolution of new sequencing technologies, researchers can now investigate the microbiome and map its influence on the environment and human health. Advances in bioinformatics methods for next-generation sequencing (NGS) data analysis have helped researchers to gain an in-depth knowledge about the taxonomic and genetic composition of microbial communities. Metagenomic-based methods have been the most commonly used approaches for microbiome analysis; however, it primarily extracts information about taxonomic composition and genetic potential of the microbiome under study, lacking quantification of the gene products (RNA and proteins). On the other hand, metatranscriptomics, the study of a microbial community's RNA expression, can reveal the dynamic gene expression of individual microbial populations and the community as a whole, ultimately providing information about the active pathways in the microbiome. In order to address the analysis of NGS data, the ASaiM analysis framework was previously developed and made available via the Galaxy platform. Although developed for both metagenomics and metatranscriptomics, the original publication demonstrated the use of ASaiM only for metagenomics, while thorough testing for metatranscriptomics data was lacking. In the current study, we have focused on validating and optimizing the tools within ASaiM for metatranscriptomics data. As a result, we deliver a robust workflow that will enable researchers to understand dynamic functional response of the microbiome in a wide variety of metatranscriptomics studies. This improved and optimized ASaiM-metatranscriptomics (ASaiM-MT) workflow is publicly available via the ASaiM framework, documented and supported with training material so that users can interrogate and characterize metatranscriptomic data, as part of larger meta-omic studies of microbiomes.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Gupta CL, Blum SE, Kattusamy K, et al (2021)

Longitudinal study on the effects of growth-promoting and therapeutic antibiotics on the dynamics of chicken cloacal and litter microbiomes and resistomes.

Microbiome, 9(1):178.

BACKGROUND: Therapeutic and growth-promoting antibiotics are frequently used in broiler production. Indirect evidence indicates that these practices are linked to the proliferation of antimicrobial resistance (AMR), the spread of antibiotic-resistant bacteria from food animals to humans, and the environment, but there is a lack of comprehensive experimental data supporting this. We investigated the effects of growth promotor (bacitracin) and therapeutic (enrofloxacin) antibiotic administration on AMR in broilers for the duration of a production cycle, using a holistic approach that integrated both culture-dependent and culture-independent methods. We specifically focused on pathogen-harboring families (Enterobacteriaceae, Enterococcaceae, and Staphylococcaceae).

RESULTS: Antibiotic-resistant bacteria and antibiotic resistance genes were ubiquitous in chicken cloaca and litter regardless of antibiotic administration. Environment (cloaca vs. litter) and growth stage were the primary drivers of variation in the microbiomes and resistomes, with increased bacterial diversity and a general decrease in abundance of the pathogen-harboring families with age. Bacitracin-fed groups had higher levels of bacitracin resistance genes and of vancomycin-resistant Enterococcaceae (total Enterococcaceae counts were not higher). Although metagenomic analyses classified 28-76% of the Enterococcaceae as the commensal human pathogens E. faecalis and E. faecium, culture-based analysis suggested that approximately 98% of the vancomycin-resistant Enterococcaceae were avian and not human-associated, suggesting differences in the taxonomic profiles of the resistant and non-resistant strains. Enrofloxacin treatments had varying effects, but generally facilitated increased relative abundance of multidrug-resistant Enterobacteriaceae strains, which were primarily E. coli. Metagenomic approaches revealed a diverse array of Staphylococcus spp., but the opportunistic pathogen S. aureus and methicillin resistance genes were not detected in culture-based or metagenomic analyses. Camphylobacteriaceae were significantly more abundant in the cloacal samples, especially in enrofloxacin-treated chickens, where a metagenome-assembled C. jejuni genome harboring fluoroquinolone and β-lactam resistance genes was identified.

CONCLUSIONS: Within a "farm-to-fork, one health" perspective, considering the evidence that bacitracin and enrofloxacin used in poultry production can select for resistance, we recommend their use be regulated. Furthermore, we suggest routine surveillance of ESBL E. coli, vancomycin-resistant E. faecalis and E. faecium, and fluoroquinolone-resistant C. jejuni strains considering their pathogenic nature and capacity to disseminate AMR to the environment. Video Abstract.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Xiong C, Singh BK, He JZ, et al (2021)

Plant developmental stage drives the differentiation in ecological role of the maize microbiome.

Microbiome, 9(1):171.

BACKGROUND: Plants live with diverse microbial communities which profoundly affect multiple facets of host performance, but if and how host development impacts the assembly, functions and microbial interactions of crop microbiomes are poorly understood. Here we examined both bacterial and fungal communities across soils, epiphytic and endophytic niches of leaf and root, and plastic leaf of fake plant (representing environment-originating microbes) at three developmental stages of maize at two contrasting sites, and further explored the potential function of phylloplane microbiomes based on metagenomics.

RESULTS: Our results suggested that plant developmental stage had a much stronger influence on the microbial diversity, composition and interkingdom networks in plant compartments than in soils, with the strongest effect in the phylloplane. Phylloplane microbiomes were co-shaped by both plant growth and seasonal environmental factors, with the air (represented by fake plants) as its important source. Further, we found that bacterial communities in plant compartments were more strongly driven by deterministic processes at the early stage but a similar pattern was for fungal communities at the late stage. Moreover, bacterial taxa played a more important role in microbial interkingdom network and crop yield prediction at the early stage, while fungal taxa did so at the late stage. Metagenomic analyses further indicated that phylloplane microbiomes possessed higher functional diversity at the early stage than the late stage, with functional genes related to nutrient provision enriched at the early stage and N assimilation and C degradation enriched at the late stage. Coincidently, more abundant beneficial bacterial taxa like Actinobacteria, Burkholderiaceae and Rhizobiaceae in plant microbiomes were observed at the early stage, but more saprophytic fungi at the late stage.

CONCLUSIONS: Our results suggest that host developmental stage profoundly influences plant microbiome assembly and functions, and the bacterial and fungal microbiomes take a differentiated ecological role at different stages of plant development. This study provides empirical evidence for host exerting strong effect on plant microbiomes by deterministic selection during plant growth and development. These findings have implications for the development of future tools to manipulate microbiome for sustainable increase in primary productivity. Video Abstract.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Roth-Schulze AJ, Penno MAS, Ngui KM, et al (2021)

Type 1 diabetes in pregnancy is associated with distinct changes in the composition and function of the gut microbiome.

Microbiome, 9(1):167.

BACKGROUND: The gut microbiome changes in response to a range of environmental conditions, life events and disease states. Pregnancy is a natural life event that involves major physiological adaptation yet studies of the microbiome in pregnancy are limited and their findings inconsistent. Pregnancy with type 1 diabetes (T1D) is associated with increased maternal and fetal risks but the gut microbiome in this context has not been characterized. By whole metagenome sequencing (WMS), we defined the taxonomic composition and function of the gut bacterial microbiome across 70 pregnancies, 36 in women with T1D.

RESULTS: Women with and without T1D exhibited compositional and functional changes in the gut microbiome across pregnancy. Profiles in women with T1D were distinct, with an increase in bacteria that produce lipopolysaccharides and a decrease in those that produce short-chain fatty acids, especially in the third trimester. In addition, women with T1D had elevated concentrations of fecal calprotectin, a marker of intestinal inflammation, and serum intestinal fatty acid-binding protein (I-FABP), a marker of intestinal epithelial damage.

CONCLUSIONS: Women with T1D exhibit a shift towards a more pro-inflammatory gut microbiome during pregnancy, associated with evidence of intestinal inflammation. These changes could contribute to the increased risk of pregnancy complications in women with T1D and are potentially modifiable by dietary means. Video abstract.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Oliva M, Mulet-Margalef N, Ochoa-De-Olza M, et al (2021)

Tumor-Associated Microbiome: Where Do We Stand?.

International journal of molecular sciences, 22(3):.

The study of the human microbiome in oncology is a growing and rapidly evolving field. In the past few years, there has been an exponential increase in the number of studies investigating associations of microbiome and cancer, from oncogenesis and cancer progression to resistance or sensitivity to specific anticancer therapies. The gut microbiome is now known to play a significant role in antitumor immune responses and in predicting the efficacy of immune-checkpoint inhibitors in cancer patients. Beyond the gut, the tumor-associated microbiome-microbe communities located either in the tumor or within its body compartment-seems to interact with the local microenvironment and the tumor immune contexture, ultimately impacting cancer progression and treatment outcome. However, pre-clinical research focusing on causality and mechanistic pathways as well as proof-of-concept studies are still needed to fully understand the potential clinical utility of microbiome in cancer patients. Moreover, there is a need for the standardization of methodology and the implementation of quality control across microbiome studies to allow for a better interpretation and greater comparability of the results reported between them. This review summarizes the accumulating evidence in the field and discusses the current and upcoming challenges of microbiome studies.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Casaburi G, Duar RM, Brown H, et al (2021)

Metagenomic insights of the infant microbiome community structure and function across multiple sites in the United States.

Scientific reports, 11(1):1472.

The gut microbiome plays an important role in early life, protecting newborns from enteric pathogens, promoting immune system development and providing key functions to the infant host. Currently, there are limited data to broadly assess the status of the US healthy infant gut microbiome. To address this gap, we performed a multi-state metagenomic survey and found high levels of bacteria associated with enteric inflammation (e.g. Escherichia, Klebsiella), antibiotic resistance genes, and signatures of dysbiosis, independent of location, age, and diet. Bifidobacterium were less abundant than generally expected and the species identified, including B. breve, B. longum and B. bifidum, had limited genetic capacity to metabolize human milk oligosaccharides (HMOs), while B. infantis strains with a complete capacity for HMOs utilization were found to be exceptionally rare. Considering microbiome composition and functional capacity, this survey revealed a previously unappreciated dysbiosis that is widespread in the contemporary US infant gut microbiome.

RevDate: 2021-09-13
CmpDate: 2021-09-13

Yu Z, Pei Y, Zhao S, et al (2021)

Metatranscriptomic analysis reveals active microbes and genes responded to short-term Cr(VI) stress.

Ecotoxicology (London, England), 30(8):1527-1537.

Heavy metals have been severely polluting the environment. However, the response mechanism of microbial communities to short-term heavy metals stress remains unclear. In this study, metagenomics (MG) and metatranscriptomics (MT) was performed to observe the microbial response to short-term Cr(VI) stress. MG data showed that 99.1% of species were similar in the control and Cr(VI) treated groups. However, MT data demonstrated that 83% of the microbes were active in which 58.7% increased, while the relative abundance of 41.3% decreased after short-term Cr(VI) incubation. The MT results also revealed 9% of microbes were dormant in samples. Genes associated with oxidative stress, Cr(VI) transport, resistance, and reduction, as well as genes with unknown functions were 2-10 times upregulated after Cr(VI) treatment. To further confirm the function of unknown genes, two genes (314 and 494) were selected to detect the Cr(VI) resistance and reduction ability. The results showed that these genes significantly increased the Cr(VI) remediation ability of Escherichia coli. MT results also revealed an increase in the expression of some rare genera (at least two times) after Cr(VI) treatment, indicating these rare species played a crucial role in microbial response to short-term Cr(VI) stress. In summary, MT is an efficient way to understand the role of active and dormant microbes in specific environmental conditions.

RevDate: 2021-09-10
CmpDate: 2021-09-10

Can-Herrera LA, Gutierrez-Canul CD, Dzul-Cervantes MAA, et al (2021)

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico.

Brazilian journal of biology = Revista brasleira de biologia, 83:e246038 pii:S1519-69842023000100213.

Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

RevDate: 2021-09-09
CmpDate: 2021-09-09

Epihov DZ, Saltonstall K, Batterman SA, et al (2021)

Legume-microbiome interactions unlock mineral nutrients in regrowing tropical forests.

Proceedings of the National Academy of Sciences of the United States of America, 118(11):.

Legume trees form an abundant and functionally important component of tropical forests worldwide with N2-fixing symbioses linked to enhanced growth and recruitment in early secondary succession. However, it remains unclear how N2-fixers meet the high demands for inorganic nutrients imposed by rapid biomass accumulation on nutrient-poor tropical soils. Here, we show that N2-fixing trees in secondary Neotropical forests triggered twofold higher in situ weathering of fresh primary silicates compared to non-N2-fixing trees and induced locally enhanced nutrient cycling by the soil microbiome community. Shotgun metagenomic data from weathered minerals support the role of enhanced nitrogen and carbon cycling in increasing acidity and weathering. Metagenomic and marker gene analyses further revealed increased microbial potential beneath N2-fixers for anaerobic iron reduction, a process regulating the pool of phosphorus bound to iron-bearing soil minerals. We find that the Fe(III)-reducing gene pool in soil is dominated by acidophilic Acidobacteria, including a highly abundant genus of previously undescribed bacteria, Candidatus Acidoferrum, genus novus. The resulting dependence of the Fe-cycling gene pool to pH determines the high iron-reducing potential encoded in the metagenome of the more acidic soils of N2-fixers and their nonfixing neighbors. We infer that by promoting the activities of a specialized local microbiome through changes in soil pH and C:N ratios, N2-fixing trees can influence the wider biogeochemical functioning of tropical forest ecosystems in a manner that enhances their ability to assimilate and store atmospheric carbon.

RevDate: 2021-09-09
CmpDate: 2021-09-09

Ewens SD, Gomberg AFS, Barnum TP, et al (2021)

The diversity and evolution of microbial dissimilatory phosphite oxidation.

Proceedings of the National Academy of Sciences of the United States of America, 118(11):.

Phosphite is the most energetically favorable chemotrophic electron donor known, with a half-cell potential (E o') of -650 mV for the PO4 3-/PO3 3- couple. Since the discovery of microbial dissimilatory phosphite oxidation (DPO) in 2000, the environmental distribution, evolution, and diversity of DPO microorganisms (DPOMs) have remained enigmatic, as only two species have been identified. Here, metagenomic sequencing of phosphite-enriched microbial communities enabled the genome reconstruction and metabolic characterization of 21 additional DPOMs. These DPOMs spanned six classes of bacteria, including the Negativicutes, Desulfotomaculia, Synergistia, Syntrophia, Desulfobacteria, and Desulfomonilia_A Comparing the DPO genes from the genomes of enriched organisms with over 17,000 publicly available metagenomes revealed the global existence of this metabolism in diverse anoxic environments, including wastewaters, sediments, and subsurface aquifers. Despite their newfound environmental and taxonomic diversity, metagenomic analyses suggested that the typical DPOM is a chemolithoautotroph that occupies low-oxygen environments and specializes in phosphite oxidation coupled to CO2 reduction. Phylogenetic analyses indicated that the DPO genes form a highly conserved cluster that likely has ancient origins predating the split of monoderm and diderm bacteria. By coupling microbial cultivation strategies with metagenomics, these studies highlighted the unsampled metabolic versatility latent in microbial communities. We have uncovered the unexpected prevalence, diversity, biochemical specialization, and ancient origins of a unique metabolism central to the redox cycling of phosphorus, a primary nutrient on Earth.

RevDate: 2021-09-09
CmpDate: 2021-09-09

Dmitrijeva M, Kahlert CR, Feigelman R, et al (2021)

Strain-Resolved Dynamics of the Lung Microbiome in Patients with Cystic Fibrosis.

mBio, 12(2):.

In cystic fibrosis, dynamic and complex communities of microbial pathogens and commensals can colonize the lung. Cultured isolates from lung sputum reveal high inter- and intraindividual variability in pathogen strains, sequence variants, and phenotypes; disease progression likely depends on the precise combination of infecting lineages. Routine clinical protocols, however, provide a limited overview of the colonizer populations. Therefore, a more comprehensive and precise identification and characterization of infecting lineages could assist in making corresponding decisions on treatment. Here, we describe longitudinal tracking for four cystic fibrosis patients who exhibited extreme clinical phenotypes and, thus, were selected from a pilot cohort of 11 patients with repeated sampling for more than a year. Following metagenomics sequencing of lung sputum, we find that the taxonomic identity of individual colonizer lineages can be easily established. Crucially, even superficially clonal pathogens can be subdivided into multiple sublineages at the sequence level. By tracking individual allelic differences over time, an assembly-free clustering approach allows us to reconstruct multiple lineage-specific genomes with clear structural differences. Our study showcases a culture-independent shotgun metagenomics approach for longitudinal tracking of sublineage pathogen dynamics, opening up the possibility of using such methods to assist in monitoring disease progression through providing high-resolution routine characterization of the cystic fibrosis lung microbiome.IMPORTANCE Cystic fibrosis patients frequently suffer from recurring respiratory infections caused by colonizing pathogenic and commensal bacteria. Although modern therapies can sometimes alleviate respiratory symptoms by ameliorating residual function of the protein responsible for the disorder, management of chronic respiratory infections remains an issue. Here, we propose a minimally invasive and culture-independent method to monitor microbial lung content in patients with cystic fibrosis at minimal additional effort on the patient's part. Through repeated sampling and metagenomics sequencing of our selected cystic fibrosis patients, we successfully classify infecting bacterial lineages and deconvolute multiple lineage variants of the same species within a given patient. This study explores the application of modern computational methods for deconvoluting lineages in the cystic fibrosis lung microbiome, an environment known to be inhabited by a heterogeneous pathogen population that complicates management of the disorder.

RevDate: 2021-09-09
CmpDate: 2021-09-09

Gushgari-Doyle S, Oremland RS, Keren R, et al (2021)

Acetylene-Fueled Trichloroethene Reductive Dechlorination in a Groundwater Enrichment Culture.

mBio, 12(1):.

In aquifers, acetylene (C2H2) is a product of abiotic degradation of trichloroethene (TCE) catalyzed by in situ minerals. C2H2 can, in turn, inhibit multiple microbial processes including TCE dechlorination and metabolisms that commonly support dechlorination, in addition to supporting the growth of acetylenotrophic microorganisms. Previously, C2H2 was shown to support TCE reductive dechlorination in synthetic, laboratory-constructed cocultures containing the acetylenotroph Pelobacter sp. strain SFB93 and Dehalococcoides mccartyi strain 195 or strain BAV1. In this study, we demonstrate TCE and perchloroethene (PCE) reductive dechlorination by a microbial community enriched from contaminated groundwater and amended with C2H2 as the sole electron donor and organic carbon source. The metagenome of the stable, enriched community was analyzed to elucidate putative community functions. A novel anaerobic acetylenotroph in the phylum Actinobacteria was identified using metagenomic analysis. These results demonstrate that the coupling of acetylenotrophy and reductive dechlorination can occur in the environment with native bacteria and broaden our understanding of biotransformation at contaminated sites containing both TCE and C2H2 IMPORTANCE Understanding the complex metabolisms of microbial communities in contaminated groundwaters is a challenge. PCE and TCE are among the most common groundwater contaminants in the United States that, when exposed to certain minerals, exhibit a unique abiotic degradation pathway in which C2H2 is a product. C2H2 can act as both an inhibitor of TCE dechlorination and of supporting metabolisms and an energy source for acetylenotrophic bacteria. Here, we combine laboratory microcosm studies with computational approaches to enrich and characterize an environmental microbial community that couples two uncommon metabolisms, demonstrating unique metabolic interactions only yet reported in synthetic, laboratory-constructed settings. Using this comprehensive approach, we have identified the first reported anaerobic acetylenotroph in the phylum Actinobacteria, demonstrating the yet-undescribed diversity of this metabolism that is widely considered to be uncommon.

RevDate: 2021-09-09
CmpDate: 2021-09-09

Khan S, Hauptman R, L Kelly (2021)

Engineering the Microbiome to Prevent Adverse Events: Challenges and Opportunities.

Annual review of pharmacology and toxicology, 61:159-179.

In the past decade of microbiome research, we have learned about numerous adverse interactions between the microbiome and medical interventions such as drugs, radiation, and surgery. What if we could alter our microbiomes to prevent these events? In this review, we discuss potential routes to mitigate microbiome adverse events, including applications from the emerging field of microbiome engineering. We highlight cases where the microbiome acts directly on a treatment, such as via differential drug metabolism, and cases where a treatment directly harms the microbiome, such as in radiation therapy. Understanding and preventing microbiome adverse events is a difficult challenge that will require a data-driven approach involving causal statistics, multiomics techniques, and a personalized means of mitigating adverse events. We propose research considerations to encourage productive work in preventing microbiome adverse events, and we highlight the many challenges and opportunities that await.

RevDate: 2021-09-08
CmpDate: 2021-09-08

Park YM, Ha E, Gu KN, et al (2020)

Host Genetic and Gut Microbial Signatures in Familial Inflammatory Bowel Disease.

Clinical and translational gastroenterology, 11(7):e00213.

INTRODUCTION: The family history of inflammatory bowel disease (IBD) has been strongly associated with risk of developing IBD. This study aimed to identify the host genetic and gut microbial signatures in familial IBD.

METHODS: Genetic analyses using genome-wide single nucleotide polymorphism genotyping and whole exome sequencing were performed to calculate weighted genetic risk scores from known IBD-associated common variants and to identify rare deleterious protein-altering variants specific to patients with familial IBD in 8 Korean families that each included more than 2 affected first-degree relatives (FDRs) and their unaffected FDR(s). In parallel, gut microbial community was analyzed by 16S rRNA sequencing of stools from the sample individuals.

RESULTS: The risk of familial IBD was not well explained by the genetic burden from common IBD-risk variants, suggesting the presence of family-shared genetic and environmental disease-risk factors. We identified 17 genes (AC113554.1, ACE, AKAP17A, AKAP9, ANK2, ASB16, ASIC3, DNPH1, DUS3L, FAM200A, FZD10, LAMA5, NUTM2F, PKN1, PRR26, WDR66, and ZC3H4) that each contained rare, potentially deleterious variants transmitted to the affected FDRs in multiple families. In addition, metagenomic analyses revealed significantly different diversity of gut microbiota and identified a number of differentially abundant taxa in affected FDRs, highlighting 22 novel familial disease-associated taxa with large abundance changes and the previously reported gut dysbiosis including low alpha diversity in IBD and 16 known IBD-specific taxa.

DISCUSSION: This study identified familial IBD-associated rare deleterious variants and gut microbial dysbiosis in familial IBD.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Li H, Zhao C, Yang Y, et al (2021)

The Influence of Gut Microbiota on the Fecundity of Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae).

Journal of insect science (Online), 21(4):.

The gut microbiota of insects usually plays an important role in the development and reproduction of their hosts. The fecundity of Henosepilachna vigintioctopunctata (Fabricius) varies greatly when they develop on different host plants. Whether and how the gut microbiota regulates the fecundity of H. vigintioctopunctata was unknown. To address this question, we used 16S rRNA sequencing to analyze the gut microbiomes of H. vigintioctopunctata adults fed on two host plant species (Solanum nigrum and Solanum melongena) and one artificial diet. The development of the ovaries and testes was also examined. Our results revealed that the diversity and abundance of gut microorganisms varied significantly in insects reared on different diets. The gut microbiota of H. vigintioctopunctata raised on the two host plants was similar, with Proteobacteria being the dominant phylum in both groups, whereas Firmicutes was the dominant phylum in the group reared on the artificial diet. The predominant microbiota in the S. nigrum group were Acinetobacter soli and Acinetobacter ursingii (Acinetobacter, Moraxellaceae); Moraxella osloensis (Enhydrobacter, Moraxellaceae); and Empedobacter brevis (Empedobacter, Weeksellaceae). The microbiota in this group are associated with high lipid metabolism. In addition, the beetles' ovaries and testes were more highly developed in the S. nigrum group than in the other two groups. These findings provide valuable information for elucidating the complex roles the gut microbiota play in the fecundity of H. vigintioctopunctata, and may also contribute to developing future novel control strategies involving this economically important pest.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Dall'Agnol B, McCulloch JA, Mayer FQ, et al (2021)

Molecular characterization of bacterial communities of two neotropical tick species (Amblyomma aureolatum and Ornithodoros brasiliensis) using rDNA 16S sequencing.

Ticks and tick-borne diseases, 12(5):101746.

Ticks are one of the main vectors of pathogens for humans and animals worldwide. However, they harbor non-pathogenic microorganisms that are important for their survival, facilitating both their nutrition and immunity. We investigated the bacterial communities associated with two neotropical tick species of human and veterinary potential health importance from Brazil: Amblyomma aureolatum and Ornithodoros brasiliensis. In A. aureolatum (adult ticks collected from wild canids from Southern Brazil), the predominant bacterial phyla were Proteobacteria (98.68%), Tenericutes (0.70%), Bacteroidetes (0.14%), Actinobacteria (0.13%), and Acidobacteria (0.05%). The predominant genera were Francisella (97.01%), Spiroplasma (0.70%), Wolbachia (0.51%), Candidatus Midichloria (0.25%), and Alkanindiges (0.13%). The predominant phyla in O. brasiliensis (adults, fed and unfed nymphs collected at the environment from Southern Brazil) were Proteobacteria (90.27%), Actinobacteria (7.38%), Firmicutes (0.77%), Bacteroidetes (0.44%), and Planctomycetes (0.22%). The predominant bacterial genera were Coxiella (87.71%), Nocardioides (1.73%), Saccharopolyspora (0.54%), Marmoricola (0.42%), and Staphylococcus (0.40%). Considering the genera with potential importance for human and animal health which can be transmitted by ticks, Coxiella sp. was found in all stages of O. brasiliensis, Francisella sp. in all stages of A. aureolatum and in unfed nymphs of O. brasiliensis, and Rickettsia sp. in females of A. aureolatum from Banhado dos Pachecos (BP) in Viamão municipality, Brazil, and in females and unfed nymphs of O. brasiliensis. These results deepen our understanding of the tick-microbiota relationship in Ixodidae and Argasidae, driving new studies with the focus on the manipulation of tick microbiota to prevent outbreaks of tick-borne diseases in South America.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Fujimoto K, Kimura Y, Allegretti JR, et al (2021)

Functional Restoration of Bacteriomes and Viromes by Fecal Microbiota Transplantation.

Gastroenterology, 160(6):2089-2102.e12.

BACKGROUND & AIMS: Fecal microbiota transplantation (FMT) is an effective therapy for recurrent Clostridioides difficile infection (rCDI). However, the overall mechanisms underlying FMT success await comprehensive elucidation, and the safety of FMT has recently become a serious concern because of the occurrence of drug-resistant bacteremia transmitted by FMT. We investigated whether functional restoration of the bacteriomes and viromes by FMT could be an indicator of successful FMT.

METHODS: The human intestinal bacteriomes and viromes from 9 patients with rCDI who had undergone successful FMT and their donors were analyzed. Prophage-based and CRISPR spacer-based host bacteria-phage associations in samples from recipients before and after FMT and in donor samples were examined. The gene functions of intestinal microorganisms affected by FMT were evaluated.

RESULTS: Metagenomic sequencing of both the viromes and bacteriomes revealed that FMT does change the characteristics of intestinal bacteriomes and viromes in recipients after FMT compared with those before FMT. In particular, many Proteobacteria, the fecal abundance of which was high before FMT, were eliminated, and the proportion of Microviridae increased in recipients. Most temperate phages also behaved in parallel with the host bacteria that were altered by FMT. Furthermore, the identification of bacterial and viral gene functions before and after FMT revealed that some distinctive pathways, including fluorobenzoate degradation and secondary bile acid biosynthesis, were significantly represented.

CONCLUSIONS: The coordinated action of phages and their host bacteria restored the recipients' intestinal flora. These findings show that the restoration of intestinal microflora functions reflects the success of FMT.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Kumar M, Kumar A, Sahu KP, et al (2021)

Deciphering core-microbiome of rice leaf endosphere: Revelation by metagenomic and microbiological analysis of aromatic and non-aromatic genotypes grown in three geographical zones.

Microbiological research, 246:126704.

We have deciphered the leaf endophytic-microbiome of aromatic (cv. Pusa Basmati-1) and non-aromatic (cv. BPT-5204) rice-genotypes grown in the mountain and plateau-zones of India by both metagenomic NGS (mNGS) and conventional microbiological methods. Microbiome analysis by sequencing V3-V4 region of ribosomal gene revealed marginally more bacterial operational taxonomic units (OTU) in the mountain zone at Palampur and Almora than plateau zone at Hazaribagh. Interestingly, the rice leaf endophytic microbiomes in mountain zone were found clustered separately from that of plateau-zone. The Bray-Curtis dissimilarity indices indicated influence of geographical location as compared to genotype per se for shaping rice endophytic microbiome composition. Bacterial phyla, Proteobacteria followed by Bacteroidetes, Firmicutes, and Actinobacteria were found abundant in all three locations. The core-microbiome analysis devulged association of Acidovorax; Acinetobacter; Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium; Aureimonas; Bradyrhizobium; Burkholderia-Caballeronia-Paraburkholderia; Enterobacter; Pantoea; Pseudomonas; Sphingomonas; and Stenotrophomonas with the leaf endosphere. The phyllosphere and spermosphere microbiota appears to have contributed to endophytic microbiota of rice leaf. SparCC network analysis of the endophytic-microbiome showed complex cooperative and competitive intra-microbial interactions among the microbial communities. Microbiological validation of mNGS data further confirmed the presence of core and transient genera such as Acidovorax, Alcaligenes, Bacillus, Chryseobacterium, Comamonas, Curtobacterium, Delftia, Microbacterium, Ochrobactrum, Pantoea, Pseudomonas, Rhizobium, Rhodococcus, Sphingobacterium, Staphylococcus, Stenotrophomonas, and Xanthomonas in the rice genotypes. We isolated, characterized and identified core-endophytic microbial communities of rice leaf for developing microbiome assisted crop management by microbiome reengineering in future.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Brand EC, Klaassen MAY, Gacesa R, et al (2021)

Healthy Cotwins Share Gut Microbiome Signatures With Their Inflammatory Bowel Disease Twins and Unrelated Patients.

Gastroenterology, 160(6):1970-1985.

BACKGROUND & AIMS: It is currently unclear whether reported changes in the gut microbiome are cause or consequence of inflammatory bowel disease (IBD). Therefore, we studied the gut microbiome of IBD-discordant and -concordant twin pairs, which offers the unique opportunity to assess individuals at increased risk of developing IBD, namely healthy cotwins from IBD-discordant twin pairs.

METHODS: Fecal samples were obtained from 99 twins (belonging to 51 twin pairs), 495 healthy age-, sex-, and body mass index-matched controls, and 99 unrelated patients with IBD. Whole-genome metagenomic shotgun sequencing was performed. Taxonomic and functional (pathways) composition was compared among healthy cotwins, IBD-twins, unrelated patients with IBD, and healthy controls with multivariable (ie, adjusted for potential confounding) generalized linear models.

RESULTS: No significant differences were observed in the relative abundance of species and pathways between healthy cotwins and their IBD-twins (false discovery rate <0.10). Compared with healthy controls, 13, 19, and 18 species, and 78, 105, and 153 pathways were found to be differentially abundant in healthy cotwins, IBD-twins, and unrelated patients with IBD, respectively (false discovery rate <0.10). Of these, 8 (42.1%) of 19 and 1 (5.6%) of 18 species, and 37 (35.2%) of 105 and 30 (19.6%) of 153 pathways overlapped between healthy cotwins and IBD-twins, and healthy cotwins and unrelated patients with IBD, respectively. Many of the shared species and pathways have previously been associated with IBD. The shared pathways include potentially inflammation-related pathways, for example, an increase in propionate degradation and L-arginine degradation pathways.

CONCLUSIONS: The gut microbiome of healthy cotwins from IBD-discordant twin pairs displays IBD-like signatures. These IBD-like microbiome signatures might precede the onset of IBD. However, longitudinal follow-up studies are needed to infer a causal relationship.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Omori K, Miyakawa H, Watanabe A, et al (2021)

The Combined Effects of Magnesium Oxide and Inulin on Intestinal Microbiota and Cecal Short-Chain Fatty Acids.

Nutrients, 13(1):.

Constipation is a common condition that occurs in many people worldwide. While magnesium oxide (MgO) is often used as the first-line drug for chronic constipation in Japan, dietary fiber intake is also recommended. Dietary fiber is fermented by microbiota to produce short-chain fatty acids (SCFAs). SCFAs are involved in regulating systemic physiological functions and circadian rhythm. We examined the effect of combining MgO and the water-soluble dietary fiber, inulin, on cecal SCFA concentration and microbiota in mice. We also examined the MgO administration timing effect on cecal SCFAs. The cecal SCFA concentrations were measured by gas chromatography, and the microbiota was determined using next-generation sequencing. Inulin intake decreased cecal pH and increased cecal SCFA concentrations while combining MgO increased the cecal pH lowered by inulin and decreased the cecal SCFA concentrations elevated by inulin. When inulin and MgO were combined, significant changes in the microbiota composition were observed compared with inulin alone. The MgO effect on the cecal acetic acid concentration was less when administered at ZT12 than at ZT0. In conclusion, this study suggests that MgO affects cecal SCFA and microbiota during inulin feeding, and the effect on acetic acid concentration is time-dependent.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Griesenauer B, González-Beiras C, Fortney KR, et al (2021)

Streptococcus pyogenes Is Associated with Idiopathic Cutaneous Ulcers in Children on a Yaws-Endemic Island.

mBio, 12(1):.

Exudative cutaneous ulcers (CU) in yaws-endemic areas are associated with Treponema pallidum subsp. pertenue (TP) and Haemophilus ducreyi (HD), but one-third of CU cases are idiopathic (IU). Using mass drug administration (MDA) of azithromycin, a yaws eradication campaign on Lihir Island in Papua New Guinea reduced but failed to eradicate yaws; IU rates remained constant throughout the campaign. To identify potential etiologies of IU, we obtained swabs of CU lesions (n = 279) and of the skin of asymptomatic controls (AC; n = 233) from the Lihir Island cohort and characterized their microbiomes using a metagenomics approach. CU bacterial communities were less diverse than those of the AC. Using real-time multiplex PCR with pathogen-specific primers, we separated CU specimens into HD-positive (HD+), TP+, HD+TP+, and IU groups. Each CU subgroup formed a distinct bacterial community, defined by the species detected and/or the relative abundances of species within each group. Streptococcus pyogenes was the most abundant organism in IU (22.65%) and was enriched in IU compared to other ulcer groups. Follow-up samples (n = 31) were obtained from nonhealed ulcers; the average relative abundance of S. pyogenes was 30.11% in not improved ulcers and 0.88% in improved ulcers, suggesting that S. pyogenes in the not improved ulcers may be azithromycin resistant. Catonella morbi was enriched in IU that lacked S. pyogenes As some S. pyogenes and TP strains are macrolide resistant, penicillin may be the drug of choice for CU azithromycin treatment failures. Our study will aid in the design of diagnostic tests and selective therapies for CU.IMPORTANCE Cutaneous ulcers (CU) affect approximately 100,000 children in the tropics each year. While two-thirds of CU are caused by Treponema pallidum subspecies pertenue and Haemophilus ducreyi, the cause(s) of the remaining one-third is unknown. Given the failure of mass drug administration of azithromycin to eradicate CU, the World Health Organization recently proposed an integrated disease management strategy to control CU. Success of this strategy requires determining the unknown cause(s) of CU. By using 16S rRNA gene sequencing of swabs obtained from CU and the skin of asymptomatic children, we identified another possible cause of skin ulcers, Streptococcus pyogenes Although S. pyogenes is known to cause impetigo and cellulitis, this is the first report implicating the organism as a causal agent of CU. Inclusion of S. pyogenes into the integrated disease management plan will improve diagnostic testing and treatment of this painful and debilitating disease of children and strengthen elimination efforts.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Debesa-Tur G, Pérez-Brocal V, Ruiz-Ruiz S, et al (2021)

Metagenomic analysis of formalin-fixed paraffin-embedded tumor and normal mucosa reveals differences in the microbiome of colorectal cancer patients.

Scientific reports, 11(1):391.

An increased risk of developing colorectal cancer (CRC) and other types of tumor is associated to Lynch syndrome (LS), an inherited condition caused by germline mutations in mismatch repair genes. We selected a cohort of LS patients that had developed CRC and had undergone surgical resection. Formalin-fixed paraffin embedded (FFPE) tissue blocks from matched colorectal and normal mucosa were used for genomic DNA extraction with a commercial kit and sequenced by high-throughput sequencing. A metagenomic approach enabled the taxonomic and functional identification of the microbial community and associated genes detected in the specimens. Slightly lower taxonomic diversity was observed in the tumor compared to the non-tumor tissue. Furthermore, the most remarkable differences between tumors and healthy tissue was the significant increase in the genus Fusobacterium in the former, in particular the species F. nucleatum, as well as Camplylobacter or Bacteroides fragilis, in accordance with previous studies of CRC. However, unlike prior studies, the present work is not based on directed detection by qPCR but instead uses a metagenomic approach to retrieve the whole bacterial community, and addresses the additional difficulty of using long-term stored FFPE samples.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Galipeau HJ, Caminero A, Turpin W, et al (2021)

Novel Fecal Biomarkers That Precede Clinical Diagnosis of Ulcerative Colitis.

Gastroenterology, 160(5):1532-1545.

BACKGROUND & AIMS: Altered gut microbiota composition and function have been associated with inflammatory bowel diseases, including ulcerative colitis (UC), but the causality and mechanisms remain unknown.

METHODS: We applied 16S ribosomal RNA gene sequencing, shotgun metagenomic sequencing, in vitro functional assays, and gnotobiotic colonizations to define the microbial composition and function in fecal samples obtained from a cohort of healthy individuals at risk for inflammatory bowel diseases (pre-UC) who later developed UC (post-UC) and matched healthy control individuals (HCs).

RESULTS: Microbiota composition of post-UC samples was different from HC and pre-UC samples; however, functional analysis showed increased fecal proteolytic and elastase activity before UC onset. Metagenomics identified more than 22,000 gene families that were significantly different between HC, pre-UC, and post-UC samples. Of these, 237 related to proteases and peptidases, suggesting a bacterial component to the pre-UC proteolytic signature. Elastase activity inversely correlated with the relative abundance of Adlercreutzia and other potentially beneficial taxa and directly correlated with known proteolytic taxa, such as Bacteroides vulgatus. High elastase activity was confirmed in Bacteroides isolates from fecal samples. The bacterial contribution and functional significance of the proteolytic signature were investigated in germ-free adult mice and in dams colonized with HC, pre-UC, or post-UC microbiota. Mice colonized with or born from pre-UC-colonized dams developed higher fecal proteolytic activity and an inflammatory immune tone compared with HC-colonized mice.

CONCLUSIONS: We have identified increased fecal proteolytic activity that precedes the clinical diagnosis of UC and associates with gut microbiota changes. This proteolytic signature may constitute a noninvasive biomarker of inflammation to monitor at-risk populations that can be targeted therapeutically with antiproteases.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Hugerth LW, Pereira M, Zha Y, et al (2020)

Assessment of In Vitro and In Silico Protocols for Sequence-Based Characterization of the Human Vaginal Microbiome.

mSphere, 5(6):.

The vaginal microbiome has been connected to a wide range of health outcomes. This has led to a thriving research environment but also to the use of conflicting methodologies to study its microbial composition. Here, we systematically assessed best practices for the sequencing-based characterization of the human vaginal microbiome. As far as 16S rRNA gene sequencing is concerned, the V1-V3 region performed best in silico, but limitations of current sequencing technologies meant that the V3-V4 region performed equally well. Both approaches presented very good agreement with qPCR quantification of key taxa, provided that an appropriate bioinformatic pipeline was used. Shotgun metagenomic sequencing presents an interesting alternative to 16S rRNA gene amplification and sequencing but requires deeper sequencing and more bioinformatic expertise and infrastructure. We assessed different tools for the removal of host reads and the taxonomic annotation of metagenomic reads, including a new, easy-to-build and -use reference database of vaginal taxa. This curated database performed as well as the best-performing previously published strategies. Despite the many advantages of shotgun sequencing, none of the shotgun approaches assessed here agreed with the qPCR data as well as the 16S rRNA gene sequencing.IMPORTANCE The vaginal microbiome has been connected to various aspects of host health, including susceptibility to sexually transmitted infections as well as gynecological cancers and pregnancy outcomes. This has led to a thriving research environment but also to conflicting available methodologies, including many studies that do not report their molecular biological and bioinformatic methods in sufficient detail to be considered reproducible. This can lead to conflicting messages and delay progress from descriptive to intervention studies. By systematically assessing best practices for the characterization of the human vaginal microbiome, this study will enable past studies to be assessed more critically and assist future studies in the selection of appropriate methods for their specific research questions.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Patin NV, Peña-Gonzalez A, Hatt JK, et al (2020)

The Role of the Gut Microbiome in Resisting Norovirus Infection as Revealed by a Human Challenge Study.

mBio, 11(6):.

Norovirus infections take a heavy toll on worldwide public health. While progress has been made toward understanding host responses to infection, the role of the gut microbiome in determining infection outcome is unknown. Moreover, data are lacking on the nature and duration of the microbiome response to norovirus infection, which has important implications for diagnostics and host recovery. Here, we characterized the gut microbiomes of subjects enrolled in a norovirus challenge study. We analyzed microbiome features of asymptomatic and symptomatic individuals at the genome (population) and gene levels and assessed their response over time in symptomatic individuals. We show that the preinfection microbiomes of subjects with asymptomatic infections were enriched in Bacteroidetes and depleted in Clostridia relative to the microbiomes of symptomatic subjects. These compositional differences were accompanied by differences in genes involved in the metabolism of glycans and sphingolipids that may aid in host resilience to infection. We further show that microbiomes shifted in composition following infection and that recovery times were variable among human hosts. In particular, Firmicutes increased immediately following the challenge, while Bacteroidetes and Proteobacteria decreased over the same time. Genes enriched in the microbiomes of symptomatic subjects, including the adenylyltransferase glgC, were linked to glycan metabolism and cell-cell signaling, suggesting as-yet unknown roles for these processes in determining infection outcome. These results provide important context for understanding the gut microbiome role in host susceptibility to symptomatic norovirus infection and long-term health outcomes.IMPORTANCE The role of the human gut microbiome in determining whether an individual infected with norovirus will be symptomatic is poorly understood. This study provides important data on microbes that distinguish asymptomatic from symptomatic microbiomes and links these features to infection responses in a human challenge study. The results have implications for understanding resistance to and treatment of norovirus infections.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Gong G, Zhou S, Luo R, et al (2020)

Metagenomic insights into the diversity of carbohydrate-degrading enzymes in the yak fecal microbial community.

BMC microbiology, 20(1):302.

BACKGROUND: Yaks are able to utilize the gastrointestinal microbiota to digest plant materials. Although the cellulolytic bacteria in the yak rumen have been reported, there is still limited information on the diversity of the major microorganisms and putative carbohydrate-metabolizing enzymes for the degradation of complex lignocellulosic biomass in its gut ecosystem.

RESULTS: Here, this study aimed to decode biomass-degrading genes and genomes in the yak fecal microbiota using deep metagenome sequencing. A comprehensive catalog comprising 4.5 million microbial genes from the yak feces were established based on metagenomic assemblies from 92 Gb sequencing data. We identified a full spectrum of genes encoding carbohydrate-active enzymes, three-quarters of which were assigned to highly diversified enzyme families involved in the breakdown of complex dietary carbohydrates, including 120 families of glycoside hydrolases, 25 families of polysaccharide lyases, and 15 families of carbohydrate esterases. Inference of taxonomic assignments to the carbohydrate-degrading genes revealed the major microbial contributors were Bacteroidaceae, Ruminococcaceae, Rikenellaceae, Clostridiaceae, and Prevotellaceae. Furthermore, 68 prokaryotic genomes were reconstructed and the genes encoding glycoside hydrolases involved in plant-derived polysaccharide degradation were identified in these uncultured genomes, many of which were novel species with lignocellulolytic capability.

CONCLUSIONS: Our findings shed light on a great diversity of carbohydrate-degrading enzymes in the yak gut microbial community and uncultured species, which provides a useful genetic resource for future studies on the discovery of novel enzymes for industrial applications.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Mokkala K, Paulin N, Houttu N, et al (2021)

Metagenomics analysis of gut microbiota in response to diet intervention and gestational diabetes in overweight and obese women: a randomised, double-blind, placebo-controlled clinical trial.

Gut, 70(2):309-318.

OBJECTIVE: Gut microbiota and diet are known to contribute to human metabolism. We investigated whether the metagenomic gut microbiota composition and function changes over pregnancy are related to gestational diabetes mellitus (GDM) and can be modified by dietary supplements, fish oil and/or probiotics.

DESIGN: The gut microbiota of 270 overweight/obese women participating in a mother-infant clinical study were analysed with metagenomics approach in early (mean gestational weeks 13.9) and late (gestational weeks 35.2) pregnancy. GDM was diagnosed with a 2 hour 75 g oral glucose tolerance test.

RESULTS: Unlike women with GDM, women without GDM manifested changes in relative abundance of bacterial species over the pregnancy, particularly those receiving the fish oil + probiotics combination. The specific bacterial species or function did not predict the onset of GDM nor did it differ according to GDM status, except for the higher abundance of Ruminococcus obeum in late pregnancy in the combination group in women with GDM compared with women without GDM. In the combination group, weak decreases over the pregnancy were observed in basic bacterial housekeeping functions.

CONCLUSIONS: The specific gut microbiota species do not contribute to GDM in overweight/obese women. Nevertheless, the GDM status may disturb maternal gut microbiota flexibility and thus limit the capacity of women with GDM to respond to diet, as evidenced by alterations in gut microbiota observed only in women without GDM. These findings may be important when considering the metabolic complications during pregnancy, but further studies with larger populations are called for to verify the findings.

RevDate: 2021-09-07
CmpDate: 2021-09-07

Hu S, Vich Vila A, Gacesa R, et al (2021)

Whole exome sequencing analyses reveal gene-microbiota interactions in the context of IBD.

Gut, 70(2):285-296.

OBJECTIVE: Both the gut microbiome and host genetics are known to play significant roles in the pathogenesis of IBD. However, the interaction between these two factors and its implications in the aetiology of IBD remain underexplored. Here, we report on the influence of host genetics on the gut microbiome in IBD.

DESIGN: To evaluate the impact of host genetics on the gut microbiota of patients with IBD, we combined whole exome sequencing of the host genome and whole genome shotgun sequencing of 1464 faecal samples from 525 patients with IBD and 939 population-based controls. We followed a four-step analysis: (1) exome-wide microbial quantitative trait loci (mbQTL) analyses, (2) a targeted approach focusing on IBD-associated genomic regions and protein truncating variants (PTVs, minor allele frequency (MAF) >5%), (3) gene-based burden tests on PTVs with MAF <5% and exome copy number variations (CNVs) with site frequency <1%, (4) joint analysis of both cohorts to identify the interactions between disease and host genetics.

RESULTS: We identified 12 mbQTLs, including variants in the IBD-associated genes IL17REL, MYRF, SEC16A and WDR78. For example, the decrease of the pathway acetyl-coenzyme A biosynthesis, which is involved in short chain fatty acids production, was associated with variants in the gene MYRF (false discovery rate <0.05). Changes in functional pathways involved in the metabolic potential were also observed in participants carrying rare PTVs or CNVs in CYP2D6, GPR151 and CD160 genes. These genes are known for their function in the immune system. Moreover, interaction analyses confirmed previously known IBD disease-specific mbQTLs in TNFSF15.

CONCLUSION: This study highlights that both common and rare genetic variants affecting the immune system are key factors in shaping the gut microbiota in the context of IBD and pinpoints towards potential mechanisms for disease treatment.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Chen J, Li H, Hird SM, et al (2021)

Sex Differences in Gut Microbial Development of Preterm Infant Twins in Early Life: A Longitudinal Analysis.

Frontiers in cellular and infection microbiology, 11:671074.

Infant gut microbiota plays a vital role in immune response, mediates neurobehavioral development and health maintenance. Studies of twins' gut microbiota found that gut microbiota composition and diversity tend to be mature and stable with increasing postnatal age (PNA). Preterm infant gut microbiome shifts dramatically when they were staying in the neonatal intensive care unit (NICU). Compositions and shifting characteristics of gut microbiota among neonatal preterm twins and triplets during their early life are still unknown, which impedes a better understanding of the mechanism underpinning neurobehavioral development and precise intervention/health of preterm neonates. This longitudinal cohort study used a twins/triplets design to investigate the interaction of genetic (e.g., male vs. female) and environmental factors influencing the development of the gut microbiome in early life. We included 39 preterm infants, 12 were Female twins/triplets (Female T/T) including 3 twins pairs and 2 triplets, 12 were male twins (Male T) including 6 twins pairs, and 15 were mixed-sex twins/triplets (Mix T/T) including 6 twins pairs and 1 triplet (8 females and 7 males) during the first four weeks of NICU stay. Weekly gut microbiota patterns between females and males were compared by linear discriminant analysis (LDA) effect size (LEfSe). Metagenomics function of gut microbiota was predicted by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Weekly function (KEGG pathways) differences between females and males were detected by using Statistical Analysis of Metagenomic Profiles (STAMP). Results found that female pairs and male pairs were significantly different in gut microbiome diversity, compositions, and predicted metabolic profiles, importantly, females and males were also significantly dissimilar within their co-twin/triplet pairs of the mixed-sex group, infants of co-twins/triplets shared more similar features than un-related infants from different twins' pair. Future research developing personalized interventions for vulnerable high-risk infants should consider sex, and the interaction of sex and environmental factors.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Zhang YZ, Jiang DY, Zhang C, et al (2021)

Pathological Impact on the Phyllosphere Microbiota of Artemisia argyi by Haze.

Journal of microbiology and biotechnology, 31(4):510-519.

The pathological impact of haze upon the phyllosphere microbiota awaits investigation. A moderate degree of haze environment and a clean control were selected in Chengdu, China. Artemisia argyi, a ubiquitously distributed and extensively applied Chinese herb, was also chosen for experiment. Total genome DNA was extracted from leaf samples, and for metagenome sequencing, an Illumina HiSeq 2500 platform was applied. The results showed that the gene numbers of phyllosphere microbiota derived from haze leaves were lower than those of the clean control. The phyllosphere microbiota derived from both haze and clean groups shared the same top ten phyla; the abundances of Proteobacteria, Actinomycetes and Anorthococcuso of the haze group were substantially increased, while Ascomycetes and Basidiomycetes decreased. At the genus level, the abundances of Nocardia, Paracoccus, Marmoricola and Knoelia from haze leaves were markedly increased, while the yeasts were statistically decreased. KEGG retrieval demonstrated that the functional genes were most annotated to metabolism. An interesting find of this work is that the phyllosphere microbiota responsible for the synthesis of primary and secondary metabolites in A. argyi were significantly increased under a haze environment. Relatively enriched genes annotated by eggNOG belong to replication, recombination and repair, and genes classified into the glycoside hydrolase and glycosyltransferase enzymes were significantly increased. In summary, we found that both structure and function of phyllosphere microbiota are globally impacted by haze, while primary and secondary metabolites responsible for haze tolerance were considerably increased. These results suggest an adaptive strategy of plants for tolerating and confronting haze damage.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Santus W, Devlin JR, J Behnsen (2021)

Crossing Kingdoms: How the Mycobiota and Fungal-Bacterial Interactions Impact Host Health and Disease.

Infection and immunity, 89(4):.

The term "microbiota" invokes images of mucosal surfaces densely populated with bacteria. These surfaces and the luminal compartments they form indeed predominantly harbor bacteria. However, research from this past decade has started to complete the picture by focusing on important but largely neglected constituents of the microbiota: fungi, viruses, and archaea. The community of commensal fungi, also called the mycobiota, interacts with commensal bacteria and the host. It is thus not surprising that changes in the mycobiota have significant impact on host health and are associated with pathological conditions such as inflammatory bowel disease (IBD). In this review we will give an overview of why the mycobiota is an important research area and different mycobiota research tools. We will specifically focus on distinguishing transient and actively colonizing fungi of the oral and gut mycobiota and their roles in health and disease. In addition to correlative and observational studies, we will discuss mechanistic studies on specific cross-kingdom interactions of fungi, bacteria, and the host.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Tan JY, Wang S, Dick GJ, et al (2020)

Co-cultivation of microbial sub-communities in microfluidic droplets facilitates high-resolution genomic dissection of microbial 'dark matter'.

Integrative biology : quantitative biosciences from nano to macro, 12(11):263-274.

While the 'unculturable' majority of the bacterial world is accessible with culture-independent tools, the inability to study these bacteria using culture-dependent approaches has severely limited our understanding of their ecological roles and interactions. To circumvent cultivation barriers, we utilize microfluidic droplets as localized, nanoliter-size bioreactors to co-cultivate subsets of microbial communities. This co-localization can support ecological interactions between a reduced number of encapsulated cells. We demonstrated the utility of this approach in the encapsulation and co-cultivation of droplet sub-communities from a fecal sample collected from a healthy human subject. With the whole genome amplification and metagenomic shotgun sequencing of co-cultivated sub-communities from 22 droplets, we observed that this approach provides accessibility to uncharacterized gut commensals for study. The recovery of metagenome-assembled genomes from one droplet sub-community demonstrated the capability to dissect the sub-communities with high-genomic resolution. In particular, genomic characterization of one novel member of the family Neisseriaceae revealed implications regarding its participation in fatty acid degradation and production of atherogenic intermediates in the human gut. The demonstrated genomic resolution and accessibility to the microbial 'dark matter' with this methodology can be applied to study the interactions of rare or previously uncultivated members of microbial communities.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Levade I, Saber MM, Midani FS, et al (2021)

Predicting Vibrio cholerae Infection and Disease Severity Using Metagenomics in a Prospective Cohort Study.

The Journal of infectious diseases, 223(2):342-351.

BACKGROUND: Susceptibility to Vibrio cholerae infection is affected by blood group, age, and preexisting immunity, but these factors only partially explain who becomes infected. A recent study used 16S ribosomal RNA amplicon sequencing to quantify the composition of the gut microbiome and identify predictive biomarkers of infection with limited taxonomic resolution.

METHODS: To achieve increased resolution of gut microbial factors associated with V. cholerae susceptibility and identify predictors of symptomatic disease, we applied deep shotgun metagenomic sequencing to a cohort of household contacts of patients with cholera.

RESULTS: Using machine learning, we resolved species, strains, gene families, and cellular pathways in the microbiome at the time of exposure to V. cholerae to identify markers that predict infection and symptoms. Use of metagenomic features improved the precision and accuracy of prediction relative to 16S sequencing. We also predicted disease severity, although with greater uncertainty than our infection prediction. Species within the genera Prevotella and Bifidobacterium predicted protection from infection, and genes involved in iron metabolism were also correlated with protection.

CONCLUSION: Our results highlight the power of metagenomics to predict disease outcomes and suggest specific species and genes for experimental testing to investigate mechanisms of microbiome-related protection from cholera.

RevDate: 2021-09-06
CmpDate: 2021-09-06

Delbeke H, Younas S, Casteels I, et al (2021)

Current knowledge on the human eye microbiome: a systematic review of available amplicon and metagenomic sequencing data.

Acta ophthalmologica, 99(1):16-25.

Insights in the ocular surface microbiome are still at an early stage and many more questions remain unanswered compared with other human-associated microbial communities. The current knowledge on the human microbiome changed our viewpoint on bacteria and human health and significantly enhanced our understanding of human pathophysiology. Also in ocular medicine, microbiome research might impact treatment. Here, we summarize the current knowledge on ocular microbiome research with a particular focus on potential confounding factors and their effects on microbiome composition. Moreover, we present the ocular surface core microbiome based on current available data and defined it as genera present in almost half of the published control cohorts with a relative abundance of at least 1%.

RevDate: 2021-09-03
CmpDate: 2021-09-03

Liu J, Liu C, J Yue (2021)

Radiotherapy and the gut microbiome: facts and fiction.

Radiation oncology (London, England), 16(1):9.

An ever-growing body of evidence has linked the gut microbiome with both the effectiveness and the toxicity of cancer therapies. Radiotherapy is an effective way to treat tumors, although large variations exist among patients in tumor radio-responsiveness and in the incidence and severity of radiotherapy-induced side effects. Relatively little is known about whether and how the microbiome regulates the response to radiotherapy. Gut microbiota may be an important player in modulating "hot" versus "cold" tumor microenvironment, ultimately affecting treatment efficacy. The interaction of the gut microbiome and radiotherapy is a bidirectional function, in that radiotherapy can disrupt the microbiome and those disruptions can influence the effectiveness of the anticancer treatments. Limited data have shown that interactions between the radiation and the microbiome can have positive effects on oncotherapy. On the other hand, exposure to ionizing radiation leads to changes in the gut microbiome that contribute to radiation enteropathy. The gut microbiome can influence radiation-induced gastrointestinal mucositis through two mechanisms including translocation and dysbiosis. We propose that the gut microbiome can be modified to maximize the response to treatment and minimize adverse effects through the use of personalized probiotics, prebiotics, or fecal microbial transplantation. 16S rRNA sequencing is the most commonly used approach to investigate distribution and diversity of gut microbiome between individuals though it only identifies bacteria level other than strain level. The functional gut microbiome can be studied using methods involving metagenomics, metatranscriptomics, metaproteomics, as well as metabolomics. Multiple '-omic' approaches can be applied simultaneously to the same sample to obtain integrated results. That said, challenges and remaining unknowns in the future that persist at this time include the mechanisms by which the gut microbiome affects radiosensitivity, interactions between the gut microbiome and combination treatments, the role of the gut microbiome with regard to predictive and prognostic biomarkers, the need for multi "-omic" approach for in-depth exploration of functional changes and their effects on host-microbiome interactions, and interactions between gut microbiome, microbial metabolites and immune microenvironment.

RevDate: 2021-09-03
CmpDate: 2021-09-03

Van Olden CC, Van de Laar AW, Meijnikman AS, et al (2021)

A systems biology approach to understand gut microbiota and host metabolism in morbid obesity: design of the BARIA Longitudinal Cohort Study.

Journal of internal medicine, 289(3):340-354.

INTRODUCTION: Prevalence of obesity and associated diseases, including type 2 diabetes mellitus, dyslipidaemia and non-alcoholic fatty liver disease (NAFLD), are increasing. Underlying mechanisms, especially in humans, are unclear. Bariatric surgery provides the unique opportunity to obtain biopsies and portal vein blood-samples.

METHODS: The BARIA Study aims to assess how microbiota and their metabolites affect transcription in key tissues and clinical outcome in obese subjects and how baseline anthropometric and metabolic characteristics determine weight loss and glucose homeostasis after bariatric surgery. We phenotype patients undergoing bariatric surgery (predominantly laparoscopic Roux-en-Y gastric bypass), before weight loss, with biometrics, dietary and psychological questionnaires, mixed meal test (MMT) and collect fecal-samples and intra-operative biopsies from liver, adipose tissues and jejunum. We aim to include 1500 patients. A subset (approximately 25%) will undergo intra-operative portal vein blood-sampling. Fecal-samples are analyzed with shotgun metagenomics and targeted metabolomics, fasted and postprandial plasma-samples are subjected to metabolomics, and RNA is extracted from the tissues for RNAseq-analyses. Data will be integrated using state-of-the-art neuronal networks and metabolic modeling. Patient follow-up will be ten years.

RESULTS: Preoperative MMT of 170 patients were analysed and clear differences were observed in glucose homeostasis between individuals. Repeated MMT in 10 patients showed satisfactory intra-individual reproducibility, with differences in plasma glucose, insulin and triglycerides within 20% of the mean difference.

CONCLUSION: The BARIA study can add more understanding in how gut-microbiota affect metabolism, especially with regard to obesity, glucose metabolism and NAFLD. Identification of key factors may provide diagnostic and therapeutic leads to control the obesity-associated disease epidemic.

RevDate: 2021-09-02

Wu X, Chauhan A, Layton AC, et al (2021)

Comparative Metagenomics of the Active Layer and Permafrost from Low-Carbon Soil in the Canadian High Arctic.

Environmental science & technology [Epub ahead of print].

Approximately 87% of the Arctic consists of low-organic carbon mineral soil, but knowledge of microbial activity in low-carbon permafrost (PF) and active layer soils remains limited. This study investigated the taxonomic composition and genetic potential of microbial communities at contrasting depths of the active layer (5, 35, and 65 cm below surface, bls) and PF (80 cm bls). We showed microbial communities in PF to be taxonomically and functionally different from those in the active layer. 16S rRNA gene sequence analysis revealed higher biodiversity in the active layer than in PF, and biodiversity decreased significantly with depth. The reconstructed 91 metagenome-assembled genomes showed that PF was dominated by heterotrophic, fermenting Bacteroidota using nitrite as their main electron acceptor. Prevalent microbes identified in the active layer belonged to bacterial taxa, gaining energy via aerobic respiration. Gene abundance in metagenomes revealed enrichment of genes encoding the plant-derived polysaccharide degradation and metabolism of nitrate and sulfate in PF, whereas genes encoding methane/ammonia oxidation, cold-shock protein, and two-component systems were generally more abundant in the active layer, particularly at 5 cm bls. The results of this study deepen our understanding of the low-carbon Arctic soil microbiome and improve prediction of the impacts of thawing PF.

RevDate: 2021-09-02
CmpDate: 2021-09-02

Dalcin Martins P, de Jong A, Lenstra WK, et al (2021)

Enrichment of novel Verrucomicrobia, Bacteroidetes, and Krumholzibacteria in an oxygen-limited methane- and iron-fed bioreactor inoculated with Bothnian Sea sediments.

MicrobiologyOpen, 10(1):e1175.

Microbial methane oxidation is a major biofilter preventing larger emissions of this powerful greenhouse gas from marine coastal areas into the atmosphere. In these zones, various electron acceptors such as sulfate, metal oxides, nitrate, or oxygen can be used. However, the key microbial players and mechanisms of methane oxidation are poorly understood. In this study, we inoculated a bioreactor with methane- and iron-rich sediments from the Bothnian Sea to investigate microbial methane and iron cycling under low oxygen concentrations. Using metagenomics, we investigated shifts in microbial community composition after approximately 2.5 years of bioreactor operation. Marker genes for methane and iron cycling, as well as respiratory and fermentative metabolism, were identified and used to infer putative microbial metabolism. Metagenome-assembled genomes representing novel Verrucomicrobia, Bacteroidetes, and Krumholzibacteria were recovered and revealed a potential for methane oxidation, organic matter degradation, and iron cycling, respectively. This work brings new hypotheses on the identity and metabolic versatility of microorganisms that may be members of such functional guilds in coastal marine sediments and highlights that microorganisms potentially composing the methane biofilter in these sediments may be more diverse than previously appreciated.

RevDate: 2021-09-02
CmpDate: 2021-09-02

Alexyuk M, Bogoyavlenskiy A, Alexyuk P, et al (2021)

Epipelagic microbiome of the Small Aral Sea: Metagenomic structure and ecological diversity.

MicrobiologyOpen, 10(1):e1142.

Microbial diversity studies regarding the aquatic communities that experienced or are experiencing environmental problems are essential for the comprehension of the remediation dynamics. In this pilot study, we present data on the phylogenetic and ecological structure of microorganisms from epipelagic water samples collected in the Small Aral Sea (SAS). The raw data were generated by massive parallel sequencing using the shotgun approach. As expected, most of the identified DNA sequences belonged to Terrabacteria and Actinobacteria (40% and 37% of the total reads, respectively). The occurrence of Deinococcus-Thermus, Armatimonadetes, Chloroflexi in the epipelagic SAS waters was less anticipated. Surprising was also the detection of sequences, which are characteristic for strict anaerobes-Ignavibacteria, hydrogen-oxidizing bacteria, and archaeal methanogenic species. We suppose that the observed very broad range of phylogenetic and ecological features displayed by the SAS reads demonstrates a more intensive mixing of water masses originating from diverse ecological niches of the Aral-Syr Darya River basin than presumed before.

RevDate: 2021-09-02
CmpDate: 2021-09-02

Castillo-Álvarez F, Pérez-Matute P, Oteo JA, et al (2021)

The influence of interferon β-1b on gut microbiota composition in patients with multiple sclerosis.

Neurologia (Barcelona, Spain), 36(7):495-503.

INTRODUCTION: The association between gut microbiota and animal models of multiple sclerosis has been well established; however, studies in humans are scarce.

METHODS: We performed a descriptive, cross-sectional study comparing the relative composition of gut microbiota in 30 patients with multiple sclerosis (15 treated with interferon β-1b, 15 not receiving this treatment) and 14 healthy controls using next generation sequencing.

RESULTS: Patients with multiple sclerosis and controls showed differences in the proportion of Euryarchaeota, Firmicutes, Proteobacteria, Actinobacteria, and Lentisphaerae phyla and in 17 bacterial species. More specifically, we found significant differences in the proportion of Firmicutes, Actinobacteria, and Lentisphaerae and 6 bacteria species between controls and untreated patients; however, these differences disappeared when compared with treated patients. Untreated patients showed a significant reduction in the proportion of Prevotella copri compared to controls, while the bacteria was significantly more abundant in patients treated with interferon β-1b than in untreated patients, with levels resembling those observed in the healthy control group.

CONCLUSION: We observed differences in gut microbiota composition between patients with multiple sclerosis and controls, and between patients treated and not treated with interferon β-1b. In most cases, no differences were observed between treated patients and healthy controls, particularly for P. copri levels. This suggests that the clinical improvements observed in patients with multiple sclerosis receiving interferon β-1b may result from the effect of the drug on gut microbiota. Longitudinal and functional studies are necessary to establish a causal relationship.

RevDate: 2021-09-01
CmpDate: 2021-09-01

Koponen KK, Salosensaari A, Ruuskanen MO, et al (2021)

Associations of healthy food choices with gut microbiota profiles.

The American journal of clinical nutrition, 114(2):605-616.

BACKGROUND: Diet has a major influence on the human gut microbiota, which has been linked to health and disease. However, epidemiological studies on associations of a healthy diet with the microbiota utilizing a whole-diet approach are still scant.

OBJECTIVES: To assess associations between healthy food choices and human gut microbiota composition, and to determine the strength of association with functional potential.

METHODS: This population-based study sample consisted of 4930 participants (ages 25-74; 53% women) in the FINRISK 2002 study. Intakes of recommended foods were assessed using a food propensity questionnaire, and responses were transformed into healthy food choices (HFC) scores. Microbial diversity (alpha diversity) and compositional differences (beta diversity) and their associations with the HFC score and its components were assessed using linear regression. Multiple permutational multivariate ANOVAs were run from whole-metagenome shallow shotgun-sequenced samples. Associations between specific taxa and HFC were analyzed using linear regression. Functional associations were derived from Kyoto Encyclopedia of Genes and Genomes orthologies with linear regression models.

RESULTS: Both microbial alpha diversity (β/SD, 0.044; SE, 6.18 × 10-5; P = 2.21 × 10-3) and beta diversity (R2, 0.12; P ≤ 1.00 × 10-3) were associated with the HFC score. For alpha diversity, the strongest associations were observed for fiber-rich breads, poultry, fruits, and low-fat cheeses (all positive). For beta diversity, the most prominent associations were observed for vegetables, followed by berries and fruits. Genera with fiber-degrading and SCFA-producing capacities were positively associated with the HFC score. The HFC score was associated positively with functions such as SCFA metabolism and synthesis, and inversely with functions such as fatty acid biosynthesis and the sulfur relay system.

CONCLUSIONS: Our results from a large, population-based survey confirm and extend findings of other, smaller-scale studies that plant- and fiber-rich dietary choices are associated with a more diverse and compositionally distinct microbiota, and with a greater potential to produce SCFAs.

RevDate: 2021-08-31
CmpDate: 2021-08-31

Silver A, Perez S, Gee M, et al (2021)

Persistence of the ground beetle (Coleoptera: Carabidae) microbiome to diet manipulation.

PloS one, 16(3):e0241529.

Host-associated microbiomes can play important roles in the ecology and evolution of their insect hosts, but bacterial diversity in many insect groups remains poorly understood. Here we examine the relationship between host environment, host traits, and microbial diversity in three species in the ground beetle family (Coleoptera: Carabidae), a group of roughly 40,000 species that synthesize a wide diversity of defensive compounds. This study used 16S amplicon sequencing to profile three species that are phylogenetically distantly related, trophically distinct, and whose defensive chemical secretions differ: Anisodactylus similis LeConte, 1851, Pterostichus serripes (LeConte, 1875), and Brachinus elongatulus Chaudoir, 1876. Wild-caught beetles were compared to individuals maintained in the lab for two weeks on carnivorous, herbivorous, or starvation diets (n = 3 beetles for each species-diet combination). Metagenomic samples from two highly active tissue types-guts, and pygidial gland secretory cells (which produce defensive compounds)-were processed and sequenced separately from those of the remaining body. Bacterial composition and diversity of these ground beetles were largely resilient to controlled changes to host diet. Different tissues within the same beetle harbor unique microbial communities, and secretory cells in particular were remarkably similar across species. We also found that these three carabid species have patterns of microbial diversity similar to those previously found in carabid beetles. These results provide a baseline for future studies of the role of microbes in the diversification of carabids.

RevDate: 2021-08-31
CmpDate: 2021-08-31

Zhao W, Ren Z, Luo Y, et al (2021)

Metagenomics analysis of the gut microbiome in healthy and bacterial pneumonia forest musk deer.

Genes & genomics, 43(1):43-53.

BACKGROUND: The forest musk deer (FMD, Moschus berezovskii) is an threatened species in China. Bacterial pneumonia was found to seriously restrict the development of FMD captive breeding. Historical evidence has demonstrated the relationship between immune system and intestinal Lactobacillus in FMD.

OBJECTIVE: We sought to elucidate the differences in the gut microbiota of healthy and bacterial pneumonia FMD.

METHODS: The bacterial pneumonia FMD was demonstrated by bacterial and pathological diagnosis, and the gut microbiome of healthy and bacterial pneumonia FMD was sequenced and analysed.

RESULTS: There are three pathogens (Pseudomonas aeruginosa, Streptococcus equinus and Trueperella pyogenes) isolated from the bacterial pneumonia FMD individuals. Compared with the healthy group, the abundance of Firmicutes and Proteobacteria in the pneumonia group was changed, and a high level of Proteobacteria was found in the pneumonia group. In addition, a higher abundance of Acinetobacter (p = 0.01) was observed in the population of the pneumonia group compared with the healthy group. Several potentially harmful bacteria and disease-related KEGG subsystems were only found in the gut of the bacterial pneumonia group. Analysis of KEGG revealed that many genes related to type IV secretion system, type IV pilus, lipopolysaccharide export system, HTH-type transcriptional regulator/antitoxin MqsA, and ArsR family transcriptional regulator were significantly enriched in the metagenome of the bacterial pneumonia FMD.

CONCLUSION: Our results demonstrated that the gut microbiome was significantly altered in the bacterial pneumonia group. Overall, our research improves the understanding of the potential role of the gut microbiota in the FMD bacterial pneumonia.

RevDate: 2021-08-31
CmpDate: 2021-08-31

Mehtani R, Roy A, V Singh (2021)

Gut Microbial Metagenomics in ACLF: The Causality-Association Conundrum.

Gastroenterology, 160(6):2205.

RevDate: 2021-08-31
CmpDate: 2021-08-31

Ngo ST, Restuadi R, McCrae AF, et al (2020)

Progression and survival of patients with motor neuron disease relative to their fecal microbiota.

Amyotrophic lateral sclerosis & frontotemporal degeneration, 21(7-8):549-562.

Gut microbiota studies have been well-investigated for neurodegenerative diseases such as Alzheimer's and Parkinson's disease, however, fewer studies have comprehensively examined the gut microbiome in Motor Neuron Disease (MND), with none examining its impact on disease prognosis. Here, we investigate MND prognosis and the fecal microbiota, using 16S rRNA case-control data from 100 individuals with extensive medical histories and metabolic measurements. We contrast the composition and diversity of fecal microbiome signatures from 49 MND and 51 healthy controls by combining current gold-standard 16S microbiome pipelines. Using stringent quality control thresholds, we conducted qualitative assessment approaches including; direct comparison of taxa, PICRUSt2 predicted metagenomics, Shannon and Chao1-index and Firmicutes/Bacteroidetes ratio. We show that the fecal microbiome of patients with MND is not significantly different from that of healthy controls that were matched by age, sex, and BMI, however there are distinct differences in Beta-diversity in some patients with MND. Weight, BMI, and metabolic and clinical features of disease in patients with MND were not related to the composition of their fecal microbiome, however, we observe a greater risk for earlier death in patients with MND with increased richness and diversity of the microbiome, and in those with greater Firmicutes to Bacteroidetes ratio. This was independent of anthropometric, metabolic, or clinical features of disease, and warrants support for further gut microbiota studies in MND. Given the disease heterogeneity in MND, and complexity of the gut microbiota, large studies are necessary to determine the detailed role of the gut microbiota and MND prognosis.

RevDate: 2021-08-30
CmpDate: 2021-08-30

Kummen M, Thingholm LB, Rühlemann MC, et al (2021)

Altered Gut Microbial Metabolism of Essential Nutrients in Primary Sclerosing Cholangitis.

Gastroenterology, 160(5):1784-1798.e0.

BACKGROUND & AIMS: To influence host and disease phenotype, compositional microbiome changes, which have been demonstrated in patients with primary sclerosing cholangitis (PSC), must be accompanied by functional changes. We therefore aimed to characterize the genetic potential of the gut microbiome in patients with PSC compared with healthy controls (HCs) and patients with inflammatory bowel disease (IBD).

METHODS: Fecal DNA from 2 cohorts (1 Norwegian and 1 German), in total comprising 136 patients with PSC (58% with IBD), 158 HCs, and 93 patients with IBD without PSC, were subjected to metagenomic shotgun sequencing, generating 17 billion paired-end sequences, which were processed using HUMAnN2 and MetaPhlAn2, and analyzed using generalized linear models and random effects meta-analyses.

RESULTS: Patients with PSC had fewer microbial genes compared with HCs (P < .0001). Compared with HCs, patients with PSC showed enrichment and increased prevalence of Clostridium species and a depletion of, for example, Eubacterium spp and Ruminococcus obeum. Patients with PSC showed marked differences in the abundance of genes related to vitamin B6 synthesis and branched-chain amino acid synthesis (Qfdr < .05). Targeted metabolomics of plasma from an independent set of patients with PSC and controls found reduced concentrations of vitamin B6 and branched-chain amino acids in PSC (P < .0001), which strongly associated with reduced liver transplantation-free survival (log-rank P < .001). No taxonomic or functional differences were detected between patients with PSC with and without IBD.

CONCLUSIONS: The gut microbiome in patients with PSC exhibits large functional differences compared with that in HCs, including microbial metabolism of essential nutrients. Alterations in related circulating metabolites associated with disease course, suggesting that microbial functions may be relevant for the disease process in PSC.

RevDate: 2021-08-30
CmpDate: 2021-08-30

De Filippis F, Pasolli E, D Ercolini (2020)

Newly Explored Faecalibacterium Diversity Is Connected to Age, Lifestyle, Geography, and Disease.

Current biology : CB, 30(24):4932-4943.e4.

Faecalibacterium is prevalent in the human gut and a promising microbe for the development of next-generation probiotics (NGPs) or biotherapeutics. Analyzing reference Faecalibacterium genomes and almost 3,000 Faecalibacterium-like metagenome-assembled genomes (MAGs) reconstructed from 7,907 human and 203 non-human primate gut metagenomes, we identified the presence of 22 different Faecalibacterium-like species-level genome bins (SGBs), some further divided in different strains according to the subject geographical origin. Twelve SGBs are globally spread in the human gut and show different genomic potential in the utilization of complex polysaccharides, suggesting that higher SGB diversity may be related with increased utilization of plant-based foods. Moreover, up to 11 different species may co-occur in the same subject, with lower diversity in Western populations, as well as intestinal inflammatory states and obesity. The newly explored Faecalibacterium diversity will be able to support the choice of strains suitable as NGPs, guided by the consideration of the differences existing in their functional potential.

RevDate: 2021-08-27
CmpDate: 2021-08-27

Aguirre-von-Wobeser E, Alonso-Sánchez A, Méndez-Bravo A, et al (2021)

Barks from avocado trees of different geographic locations have consistent microbial communities.

Archives of microbiology, 203(7):4593-4607.

Bark is a permanent surface for microbial colonization at the interface of trees and the surrounding air, but little is known about its microbial communities. We used shotgun metagenomic sequencing to analyze the bark microbiomes of avocado trees from two orchards, and compared one of them to rhizospheric soil. It was shown that the microbial communities of avocado bark have a well-defined taxonomic structure, with consistent patterns of abundance of bacteria, fungi, and archaea, even in trees from two different locations. Bark microbial communities were distinct from rhizospheric soil, although they showed overlap in some taxa. Thus, avocado bark is a well-defined environment, providing niches for specific taxonomic groups, many of which are also found in other aerial plant tissues. The present in-depth characterization of bark microbial communities can form a basis for their future manipulation for agronomical purposes.

RevDate: 2021-08-27
CmpDate: 2021-08-27

Sun Z, Huang S, Zhang M, et al (2021)

Challenges in benchmarking metagenomic profilers.

Nature methods, 18(6):618-626.

Accurate microbial identification and abundance estimation are crucial for metagenomics analysis. Various methods for classification of metagenomic data and estimation of taxonomic profiles, broadly referred to as metagenomic profilers, have been developed. Nevertheless, benchmarking of metagenomic profilers remains challenging because some tools are designed to report relative sequence abundance while others report relative taxonomic abundance. Here we show how misleading conclusions can be drawn by neglecting this distinction between relative abundance types when benchmarking metagenomic profilers. Moreover, we show compelling evidence that interchanging sequence abundance and taxonomic abundance will influence both per-sample summary statistics and cross-sample comparisons. We suggest that the microbiome research community pay attention to potentially misleading biological conclusions arising from this issue when benchmarking metagenomic profilers, by carefully considering the type of abundance data that were analyzed and interpreted and clearly stating the strategy used for metagenomic profiling.

RevDate: 2021-08-27
CmpDate: 2021-08-27

Olm MR, Crits-Christoph A, Bouma-Gregson K, et al (2021)

inStrain profiles population microdiversity from metagenomic data and sensitively detects shared microbial strains.

Nature biotechnology, 39(6):727-736.

Coexisting microbial cells of the same species often exhibit genetic variation that can affect phenotypes ranging from nutrient preference to pathogenicity. Here we present inStrain, a program that uses metagenomic paired reads to profile intra-population genetic diversity (microdiversity) across whole genomes and compares microbial populations in a microdiversity-aware manner, greatly increasing the accuracy of genomic comparisons when benchmarked against existing methods. We use inStrain to profile >1,000 fecal metagenomes from newborn premature infants and find that siblings share significantly more strains than unrelated infants, although identical twins share no more strains than fraternal siblings. Infants born by cesarean section harbor Klebsiella with significantly higher nucleotide diversity than infants delivered vaginally, potentially reflecting acquisition from hospital rather than maternal microbiomes. Genomic loci that show diversity in individual infants include variants found between other infants, possibly reflecting inoculation from diverse hospital-associated sources. inStrain can be applied to any metagenomic dataset for microdiversity analysis and rigorous strain comparison.

RevDate: 2021-08-27
CmpDate: 2021-08-27

Zhang HT, Wang H, Wu HS, et al (2021)

Comparison of viromes in vaginal secretion from pregnant women with and without vaginitis.

Virology journal, 18(1):11.

BACKGROUND: Although some studies have investigated the bacterial community in vaginal tract of pregnant women, there are few reports about the viral community (virome) in this type of microenvironment.

METHODS: To investigate the composition of virome in vaginal secretion samples, 40 vaginal secretion samples from pregnant women with vaginitis and 20 vaginal secretion samples from pregnant women without vaginitis, pooled into 4 and 2 sample pools, respectively, were subjected to viral metagenomic analysis.

RESULTS: Results indicated virus sequences showing similarity to human papillomavirus (HPV), anellovirus, and norovirus were recovered from this cohort of pregnant women. Further analysis indicated that 15 different defined types and one unclassified type of HPV were detected from pregnant women with vaginitis while only 3 defined types of HPV were detected in pregnant women without vaginitis. Five different groups of viruses from the family Anelloviridae were present in pregnant women with but none of them were detected in pregnant women without vaginitis. Norovirus was detected in 3 out of the 4 sample pools from pregnant women with vaginitis but none in the pregnant women without vaginitis. Twelve complete genomes belonging to 10 different types of HPV, and 5 novel anllovirus genomes belonging 2 different genera in Anelloviridae were acquired from these libraries, based on which phylogenetical analysis and pairwise sequence comparison were performed. Phageome in these samples was also briefly characterized and compared between two groups.

CONCLUSION: Our data suggested that virome might play an important role in the progression of vaginitis in pregnant women.

RevDate: 2021-08-26
CmpDate: 2021-08-26

Das Q, Shay J, Gauthier M, et al (2021)

Effects of Vaccination Against Coccidiosis on Gut Microbiota and Immunity in Broiler Fed Bacitracin and Berry Pomace.

Frontiers in immunology, 12:621803.

Feeding practices have been found to influence gut microbiota which play a major role in immunity of poultry. In the present study, changes in cecal microbiota and humoral responses resulting in the 55 ppm bacitracin (BACI), 1% each of cranberry (CP1) and wild blueberry (BP1) pomace alone or in combination (CP+BP) feeding in broiler Cobb 500 vaccinated or not against coccidiosis were investigated. In the non-vaccinated group, no significant treatment effects were observed on performance parameters. Vaccination significantly affected bird's performance parameters particularly during the growing phase from 10 to 20 days of age. In general, the prevalence of coccidiosis and necrotic enteritis (NE) was reduced by vaccination (P < 0.05). BACI-treated birds showed low intestinal lesion scores, and both CP1 and BP1 feed supplementations reduced Eimeria acervulina and Clostridium perfringens incidences similar to BACI. Vaccination induced change in serum enzymes, minerals, and lipid levels in 21-day old birds while, levels of triglyceride (TRIG) and non-esterified fatty acids (NEFA) were higher (P < 0.05) in CP1 treated non-vaccinated group than in the control. The levels of NEFA were lower in BACI- and CP1-fed birds than in the control in non-vaccinated day 28 old birds. The highest levels of all estimated three immunoglobulins (IgY, IgM, and IgA) were found in the vaccinated birds. Metagenomics analysis of the cecal bacterial community in 21-day old birds showed the presence of Firmicutes (90%), Proteobacteria (5%), Actinobacteria (2%), and Bacteroidetes (2%). In the vaccinated group, an effect of BACI was noted on Proteobacteria (P = 0.03). Vaccination and/or dietary treatments influenced the population of Lactobacillaceae, Enterobacteriaceae, Clostridiaceae, and Streptococcaceae which were among the most abundant families. Overall, this study revealed that besides their beneficial effects on performance, alike bacitracin, berry pomaces in poultry feed have profound impacts on the chicken cecal microbiota and blood metabolites that could be influenced by vaccination against coccidiosis.

RevDate: 2021-08-26
CmpDate: 2021-06-25

Amar Y, Lagkouvardos I, Silva RL, et al (2021)

Pre-digest of unprotected DNA by Benzonase improves the representation of living skin bacteria and efficiently depletes host DNA.

Microbiome, 9(1):123.

BACKGROUND: The identification of microbiota based on next-generation sequencing (NGS) of extracted DNA has drastically improved our understanding of the role of microbial communities in health and disease. However, DNA-based microbiome analysis cannot per se differentiate between living and dead microorganisms. In environments such as the skin, host defense mechanisms including antimicrobial peptides and low cutaneous pH result in a high microbial turnover, likely resulting in high numbers of dead cells present and releasing substantial amounts of microbial DNA. NGS analyses may thus lead to inaccurate estimations of microbiome structures and consequently functional capacities.

RESULTS: We investigated in this study the feasibility of a Benzonase-based approach (BDA) to pre-digest unprotected DNA, i.e., of dead microbial cells, as a method to overcome these limitations, thus offering a more accurate assessment of the living microbiome. A skin mock community as well as skin microbiome samples were analyzed using 16S rRNA gene sequencing and metagenomics sequencing after DNA extraction with and without a Benzonase digest to assess bacterial diversity patterns. The BDA method resulted in less reads from dead bacteria both in the skin mock community and skin swabs spiked with either heat-inactivated bacteria or bacterial-free DNA. This approach also efficiently depleted host DNA reads in samples with high human-to-microbial DNA ratios, with no obvious impact on the microbiome profile. We further observed that low biomass samples generate an α-diversity bias when the bacterial load is lower than 105 CFU and that Benzonase digest is not sufficient to overcome this bias.

CONCLUSIONS: The BDA approach enables both a better assessment of the living microbiota and depletion of host DNA reads. Video abstract.

RevDate: 2021-08-26
CmpDate: 2021-08-26

Ali P, Chen F, Hassan F, et al (2021)

Bacterial community characterization of Batura Glacier in the Karakoram Range of Pakistan.

International microbiology : the official journal of the Spanish Society for Microbiology, 24(2):183-196.

High-altitude cold habitats of the Karakoram are rarely explored for their bacterial community characterization and metabolite productions. In the present study, bacterial communities in ice, water, and sediments of Batura Glacier were investigated using culture-dependent and culture-independent methods. Twenty-seven cold-adapted bacterial strains (mostly psychrotrophic) were isolated using R2A, Tryptic Soy Agar (TSA), and Luria-Bertani (LB) media, at 4 °C and 15 °C. Most of the isolates exhibited growth at a wide range of temperature (4-35 °C), pH (5-12), and salinity (1-6%). Among the bacterial isolates, 52% were identified as Gram-positive and the remaining 48% represented as Gram-negative. The results of phylogenetic analysis indicated that all the culturable bacteria belonged to 3 major phylogenetic groups, i.e., Actinobacteria (48%), Bacteroidetes (26%), and Proteobacteria (22%), while Flavobacterium (26%), Arthrobacter (22%), and Pseudomonas (19%) were represented as the dominant genera. Similarly, Illumina amplicon sequencing of 16S rRNA genes after PCR amplification of DNA from the whole community revealed dominance of the same phylogenetic groups, Proteobacteria, Actinobacteria, and Bacteroidetes, while Arthrobacter, Mycoplana, Ochrobactrum, Kaistobacter, Janthinobacterium, and Flavobacterium were found as the dominant genera. Among the culturable isolates, 70% demonstrated activity for cellulases, 48% lipases, 41% proteases, 41% DNases, and only 7% for amylases. Most of the glacial isolates demonstrated antimicrobial activity against other microorganisms including the multiple-drug-resistant strains of Candida albicans, Klebsiella pneumoniae, Acinetobacter sp., and Bacillus sp. 67% of Gram-negative while 46% of Gram-positive glacial bacteria were resistant to trimethoprim/sulfamethoxazole. Resistance against methicillin and vancomycin among the Gram-positive isolates was 23% and 15%, respectively, while 11% of the Gram-negative isolates exhibited resistance against both colistin sulfate and nalidixic acid.

RevDate: 2021-08-26
CmpDate: 2021-08-26

Afolayan AO, FA Ayeni (2020)

Metagenomic Analysis of Bacterial Communities in Water and Soil of the Fulani and non-Fulani in Nigeria.

Journal of infection in developing countries, 14(12):.

INTRODUCTION: Interactions between environmental factors (water and soil) and humans are inevitable, particularly in rural and semi-urbanized regions. As such, knowledge on the microbial constituents of these environmental factors is key to understanding potential risk to public health. However, the microbial profile of soil and water present in vulnerable human communities in Nigeria is currently unknown. This study sought to investigate the composition of soil and water microbiota in the environment inhabited by recently studied human communities (the Fulani nomadic group and the urbanized Jarawa ethnic group) and estimate the contribution of these environmental factors to the microbiome of the aforementioned human communities.

METHODOLOGY: Soil and water samples were collected from the Fulani and non-Fulani community in Jengre (Plateau State, Nigeria) and Jos (Plateau State, Nigeria), respectively. Genomic DNA was extracted from these environmental samples, followed by Illumina sequencing of the V4 region of the 16S rRNA gene and bioinformatics analysis via Quantitative Insights into Microbial Ecology QIIME.

RESULTS: There is abundance of Proteobacteria (43%) signature members in soil samples obtained from both human communities. Analysis of the water samples revealed the abundance of Proteobacteria, particularly in water sourced from the borehole (Fulani). Pseudomonas (30%) had higher relative abundance in the drinking water of the Fulani.

CONCLUSIONS: The drinking water of the Fulani could be a potential health risk to the studied Fulani community. Factors that increase the abundance of public health threats and health risk, such as hygiene practices, soil and water quality need to be studied further for the improvement of health in vulnerable populations.

RevDate: 2021-08-25
CmpDate: 2021-08-25

Rai A, A Bhattacharjee (2021)

Molecular profiling of microbial community structure and their CAZymes via metagenomics, from Tsomgo lake in the Eastern Himalayas.

Archives of microbiology, 203(6):3135-3146.

The present study is the first of its kind which is focused on Tsomgo lake, a high-altitude lake, located in the Eastern Himalayas of Sikkim. To get a major insight into the bacterial diversity, the shotgun sequencing was carried out in Illumina platform. Our results showed that both the samples TLSS1 (soil) and TLSW1 (water), had Proteobacteria as the most abundant taxa. Cluster of Orthologous group (COG) functional category of TLSS1 has 1,46,965 predicted functions. Cluster of Orthologous Group (COG) functional category of TLSW1 has 1,34,773 predicted functions. Kyoto Encyclopedia of Gene and Genomes (KEGG) functional category of TLSS1 has 1,76,825 predicted functions, most of the sequence fall in metabolism followed by Environmental information processing function. (KEGG) functional category of TLSW1 has 1,62,696 predicted functions and it follows the same pattern as TLSS1. Our studies also provide insight into the presence of distribution of different carbohydrate-active enzymes (CAZymes) present in Tsomgo lake. We have found that in case of both the samples TLSW1 and TLSS1, GlycosylTransferases were active followed by GlycosylHydrolase. The result found, represents for the first time very important findings related to the microbial diversity and the abundance of CAZymes in Tsomgo lake one of the pristine high-altitude lakes in Sikkim.

RevDate: 2021-08-25
CmpDate: 2021-08-25

Camarillo-Guerrero LF, Almeida A, Rangel-Pineros G, et al (2021)

Massive expansion of human gut bacteriophage diversity.

Cell, 184(4):1098-1109.e9.

Bacteriophages drive evolutionary change in bacterial communities by creating gene flow networks that fuel ecological adaptions. However, the extent of viral diversity and its prevalence in the human gut remains largely unknown. Here, we introduce the Gut Phage Database, a collection of ∼142,000 non-redundant viral genomes (>10 kb) obtained by mining a dataset of 28,060 globally distributed human gut metagenomes and 2,898 reference genomes of cultured gut bacteria. Host assignment revealed that viral diversity is highest in the Firmicutes phyla and that ∼36% of viral clusters (VCs) are not restricted to a single species, creating gene flow networks across phylogenetically distinct bacterial species. Epidemiological analysis uncovered 280 globally distributed VCs found in at least 5 continents and a highly prevalent phage clade with features reminiscent of p-crAssphage. This high-quality, large-scale catalog of phage genomes will improve future virome studies and enable ecological and evolutionary analysis of human gut bacteriophages.

RevDate: 2021-08-25
CmpDate: 2021-08-25

Villmones HC, Halland A, Stenstad T, et al (2021)

The cultivable microbiota of the human distal ileum.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 27(6):912.e7-912.e13.

OBJECTIVES: The existing literature on the microbiota of the ileum is inconsistent. To further characterize the microbiota, we analysed samples obtained directly from resected ileums used for urinary diversion after radical cystectomy.

METHODS: We included 150 patients with bladder cancer operated on from March 2016 to March 2019. Samples obtained by rubbing a swab against the ileal mucosa 25 cm from the ileocecal valve were cultivated at the local laboratory. Microbial colonies were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF).

RESULTS: The microbial density of the distal ileum was low. Among our samples, 79% (95% confidence interval (CI) 71%, 84%) harboured less than 1.6 × 104 cfu/mL, whereas 36% (95% CI 28%, 44%) harboured less than 1.6 × 103 cfu/mL. The flora was dominated by viridans streptococci, Candida, Actinomyces, Rothia and Lactobacillus species. Colon-related bacteria i.e. strict anaerobic bacteria, Enterobacteriales and enterococci, were recovered from 14% of the samples. Constipation was associated with increased recovery of colon-related bacteria. Antibiotic treatment prior to surgical procedures did not affect culture results. Increased age was significantly associated with more substantial fungal growth and use of proton pump inhibitors seemed to increase both bacterial and fungal growth.

CONCLUSIONS: The microbiota of the human distal ileum is sparse and differs significantly from the colonic microbiota both quantitatively and by composition. These findings contradict recent metagenomics studies based on samples collected by retrograde colonoscopy and emphasize the crucial importance of adequate sampling techniques.

RevDate: 2021-08-25
CmpDate: 2021-08-25

Alferink LJM, Radjabzadeh D, Erler NS, et al (2021)

Microbiomics, Metabolomics, Predicted Metagenomics, and Hepatic Steatosis in a Population-Based Study of 1,355 Adults.

Hepatology (Baltimore, Md.), 73(3):968-982.

BACKGROUND AND AIMS: Previous small studies have appraised the gut microbiome (GM) in steatosis, but large-scale studies are lacking. We studied the association of the GM diversity and composition, plasma metabolites, predicted functional metagenomics, and steatosis.

APPROACH AND RESULTS: This is a cross-sectional analysis of the prospective population-based Rotterdam Study. We used 16S ribosomal RNA gene sequencing and determined taxonomy using the SILVA reference database. Alpha diversity and beta diversity were calculated using the Shannon diversity index and Bray-Curtis dissimilarities. Differences were tested across steatosis using permutational multivariate analysis of variance. Hepatic steatosis was diagnosed by ultrasonography. We subsequently selected genera using regularized regression. The functional metagenome was predicted based on the GM using Kyoto Encyclopedia of Genes and Genomes pathways. Serum metabolomics were assessed using high-throughput proton nuclear magnetic resonance. All analyses were adjusted for age, sex, body mass index, alcohol, diet, and proton-pump inhibitors. We included 1,355 participants, of whom 472 had steatosis. Alpha diversity was lower in steatosis (P = 1.1∙10-9), and beta diversity varied across steatosis strata (P = 0.001). Lasso selected 37 genera of which three remained significantly associated after adjustment (Coprococcus3: β = -65; Ruminococcus Gauvreauiigroup: β = 62; and Ruminococcus Gnavusgroup: β = 45, Q-value = 0.037). Predicted metagenome analyses revealed that pathways of secondary bile-acid synthesis and biotin metabolism were present, and D-alanine metabolism was absent in steatosis. Metabolic profiles showed positive associations for aromatic and branched chain amino acids and glycoprotein acetyls with steatosis and R. Gnavusgroup, whereas these metabolites were inversely associated with alpha diversity and Coprococcus3.

CONCLUSIONS: We confirmed, on a large-scale, the lower microbial diversity and association of Coprococcus and Ruminococcus Gnavus with steatosis. We additionally showed that steatosis and alpha diversity share opposite metabolic profiles.

RevDate: 2021-08-24
CmpDate: 2021-08-24

Christiansen H, Heindler FM, Hellemans B, et al (2021)

Facilitating population genomics of non-model organisms through optimized experimental design for reduced representation sequencing.

BMC genomics, 22(1):625.

BACKGROUND: Genome-wide data are invaluable to characterize differentiation and adaptation of natural populations. Reduced representation sequencing (RRS) subsamples a genome repeatedly across many individuals. However, RRS requires careful optimization and fine-tuning to deliver high marker density while being cost-efficient. The number of genomic fragments created through restriction enzyme digestion and the sequencing library setup must match to achieve sufficient sequencing coverage per locus. Here, we present a workflow based on published information and computational and experimental procedures to investigate and streamline the applicability of RRS.

RESULTS: In an iterative process genome size estimates, restriction enzymes and size selection windows were tested and scaled in six classes of Antarctic animals (Ostracoda, Malacostraca, Bivalvia, Asteroidea, Actinopterygii, Aves). Achieving high marker density would be expensive in amphipods, the malacostracan target taxon, due to the large genome size. We propose alternative approaches such as mitogenome or target capture sequencing for this group. Pilot libraries were sequenced for all other target taxa. Ostracods, bivalves, sea stars, and fish showed overall good coverage and marker numbers for downstream population genomic analyses. In contrast, the bird test library produced low coverage and few polymorphic loci, likely due to degraded DNA.

CONCLUSIONS: Prior testing and optimization are important to identify which groups are amenable for RRS and where alternative methods may currently offer better cost-benefit ratios. The steps outlined here are easy to follow for other non-model taxa with little genomic resources, thus stimulating efficient resource use for the many pressing research questions in molecular ecology.

RevDate: 2021-08-24
CmpDate: 2021-08-24

Wille M, Geoghegan JL, EC Holmes (2021)

How accurately can we assess zoonotic risk?.

PLoS biology, 19(4):e3001135.

Identifying the animal reservoirs from which zoonotic viruses will likely emerge is central to understanding the determinants of disease emergence. Accordingly, there has been an increase in studies attempting zoonotic "risk assessment." Herein, we demonstrate that the virological data on which these analyses are conducted are incomplete, biased, and rapidly changing with ongoing virus discovery. Together, these shortcomings suggest that attempts to assess zoonotic risk using available virological data are likely to be inaccurate and largely only identify those host taxa that have been studied most extensively. We suggest that virus surveillance at the human-animal interface may be more productive.

RevDate: 2021-08-24
CmpDate: 2021-08-24

Guk J, Guedj J, Burdet C, et al (2021)

Modeling the Effect of DAV132, a Novel Colon-Targeted Adsorbent, on Fecal Concentrations of Moxifloxacin and Gut Microbiota Diversity in Healthy Volunteers.

Clinical pharmacology and therapeutics, 109(4):1045-1054.

To prevent antibiotic-induced perturbations on gut microbiota, DAV132, a novel colon-targeted adsorbent, which sequesters antibiotic residues in the lower gastrointestinal tract, was developed. We built an integrated pharmacological model of how DAV132 reduces fecal free moxifloxacin and preserves gut microbiota. We used plasma and fecal free moxifloxacin concentrations, and Shannon diversity index from 16S ribosomal RNA gene metagenomics analysis of fecal microbiota, of 143 healthy volunteers assigned randomly to receive moxifloxacin only, or with 10 DAV132 dose regimens, or to a control group. We modeled reduced fecal moxifloxacin concentrations using a transit model for DAV132 kinetics and a Michaelis-Menten model with an effect of the amount of activated charcoal on adsorption efficacy. Changes in moxifloxacin-induced perturbations on gut microbiota diversity were then quantified through a turnover model with the Emax model. With the developed model, the efficiency of pharmacokinetic antagonism and its consequences on gut microbiota diversity were quantified.

RevDate: 2021-08-24
CmpDate: 2021-08-24

Gambardella J, Castellanos V, G Santulli (2021)

Standardizing translational microbiome studies and metagenomic analyses.

Cardiovascular research, 117(3):640-642.

RevDate: 2021-08-23
CmpDate: 2021-08-23

Stražar M, Temba GS, Vlamakis H, et al (2021)

Gut microbiome-mediated metabolism effects on immunity in rural and urban African populations.

Nature communications, 12(1):4845.

The human gut microbiota is increasingly recognized as an important factor in modulating innate and adaptive immunity through release of ligands and metabolites that translocate into circulation. Urbanizing African populations harbor large intestinal diversity due to a range of lifestyles, providing the necessary variation to gauge immunomodulatory factors. Here, we uncover a gradient of intestinal microbial compositions from rural through urban Tanzanian, towards European samples, manifested both in relative abundance and genomic variation observed in stool metagenomics. The rural population shows increased Bacteroidetes, led by Prevotella copri, but also presence of fungi. Measured ex vivo cytokine responses were significantly associated with 34 immunomodulatory microbes, which have a larger impact on circulating metabolites than non-significant microbes. Pathway effects on cytokines, notably TNF-α and IFN-γ, differential metabolome analysis and enzyme copy number enrichment converge on histidine and arginine metabolism as potential immunomodulatory pathways mediated by Bifidobacterium longum and Akkermansia muciniphila.

RevDate: 2021-08-23
CmpDate: 2021-08-23

Mota-Gutierrez J, Ferrocino I, Giordano M, et al (2021)

Influence of Taxonomic and Functional Content of Microbial Communities on the Quality of Fermented Cocoa Pulp-Bean Mass.

Applied and environmental microbiology, 87(14):e0042521.

Microbial metabolism drives changes in the physicochemical properties and, consequently, the sensory characteristics of fermented cocoa beans. In this context, information regarding the structure, function, and metabolic potential of microbial communities' present during cocoa pulp-bean mass fermentation is limited, especially concerning the formation of aromatic compounds. To bridge the gap, the metagenome of fermented cocoa pulp-bean mass (Criollo and Forastero) has been investigated using shotgun metagenomics coupled with physicochemical, microbiological, quality, and sensory analyses to explore the impact of microbial communities on the quality of fermented cocoa pulp-bean mass on one farm in one season and in one region under the same environmental conditions. Our findings showed that the metagenomic diversity in cocoa, the fermentation length, and the diversity and function of metagenome-assembled genomes (MAGs) greatly influence the resulting distinctive flavors. From the metabolic perspective, multiple indicators suggest that the heterolactic metabolism was more dominant in Criollo fermentations. KEGG genes were linked with the biosynthesis of acetic acid, ethanol, lactic acid, acetoin, and phenylacetaldehyde during Criollo and Forastero fermentations. MAGs belonging to Lactiplantibacillus plantarum, Limosilactobacillus reuteri, and Acetobacter pasteurianus were the most prevalent. Fermentation time and roasting are the most important determinants of cocoa quality, while the difference between the two varieties are relatively minor. The assessment of microbiological and chemical analysis is urgently needed for developing fermentation protocols according to regions, countries, and cocoa varieties to guarantee safety and desirable flavor development. IMPORTANCE Monitoring the composition, structure, functionalities, and metabolic potential encoded at the level of DNA of fermented cocoa pulp-bean mass metagenome is of great importance for food safety and quality implications.

RevDate: 2021-08-23
CmpDate: 2021-08-23

Paul AA, Hoffman KL, Hagan JL, et al (2020)

Fungal cutaneous microbiome and host determinants in preterm and term neonates.

Pediatric research, 88(2):225-233.

BACKGROUND: The neonatal cutaneous mycobiome has not been characterized in preterm infants. Invasive fungal infections in preterm neonates are associated with high mortality. The immaturity of the preterm skin predisposes neonates to invasive infection by skin colonizers. We report the clinical and host determinants that influence the skin mycobiome.

METHODS: Skin swabs from the antecubital fossa, forehead, and gluteal region of 15 preterm and 15 term neonates were obtained during the first 5 weeks of life. The mycobiome was sequenced using the conserved pan-fungal ITS2 region. Blood samples were used to genotype immune modulating genes. Clinical metadata was collected to determine the clinical predictors of the abundance and diversity of the skin mycobiome.

RESULTS: The neonatal mycobiome is characterized by few taxa. Alpha diversity of the mycobiome is influenced by antibiotic exposure, the forehead body site, and the neonatal intensive care unit (NICU) environment. Beta diversity varies with mode of delivery, diet, and body site. The host determinants of the cutaneous microbiome include single-nucleotide polymorphisms in TLR4, NLRP3,CARD8, and NOD2.

CONCLUSION: The neonatal cutaneous mycobiome is composed of few genera and is influenced by clinical factors and host genetics, the understanding of which will inform preventive strategies against invasive fungal infections.

RevDate: 2021-08-20
CmpDate: 2021-08-20

Whon TW, Shin NR, Kim JY, et al (2021)

Omics in gut microbiome analysis.

Journal of microbiology (Seoul, Korea), 59(3):292-297.

Our understanding of the interactions between microbial communities and their niche in the host gut has improved owing to recent advances in environmental microbial genomics. Integration of metagenomic and metataxonomic sequencing data with other omics data to study the gut microbiome has become increasingly common, but downstream analysis after data integration and interpretation of complex omics data remain challenging. Here, we review studies that have explored the gut microbiome signature using omics approaches, including metagenomics, metataxonomics, metatranscriptomics, and metabolomics. We further discuss recent analytics programs to analyze and integrate multi-omics datasets and further utilization of omics data with other advanced techniques, such as adaptive immune receptor repertoire sequencing, microbial culturomics, and machine learning, to evaluate important microbiome characteristics in the gut.

RevDate: 2021-08-20
CmpDate: 2021-08-20

Gwak HJ, Lee SJ, M Rho (2021)

Application of computational approaches to analyze metagenomic data.

Journal of microbiology (Seoul, Korea), 59(3):233-241.

Microorganisms play a vital role in living systems in numerous ways. In the soil or ocean environment, microbes are involved in diverse processes, such as carbon and nitrogen cycle, nutrient recycling, and energy acquisition. The relation between microbial dysbiosis and disease developments has been extensively studied. In particular, microbial communities in the human gut are associated with the pathophysiology of several chronic diseases such as inflammatory bowel disease and diabetes. Therefore, analyzing the distribution of microorganisms and their associations with the environment is a key step in understanding nature. With the advent of next-generation sequencing technology, a vast amount of metagenomic data on unculturable microbes in addition to culturable microbes has been produced. To reconstruct microbial genomes, several assembly algorithms have been developed by incorporating metagenomic features, such as uneven depth. Since it is difficult to reconstruct complete microbial genomes from metagenomic reads, contig binning approaches were suggested to collect contigs that originate from the same genome. To estimate the microbial composition in the environment, various methods have been developed to classify individual reads or contigs and profile bacterial proportions. Since microbial communities affect their hosts and environments through metabolites, metabolic profiles from metagenomic or metatranscriptomic data have been estimated. Here, we provide a comprehensive review of computational methods that can be applied to investigate microbiomes using metagenomic and metatranscriptomic sequencing data. The limitations of metagenomic studies and the key approaches to overcome such problems are discussed.

RevDate: 2021-08-20
CmpDate: 2021-08-20

Liu J, Deng XC, Li XY, et al (2020)

Intramuscular injection of tetracycline decreased gut microbial diversity in mouse.

Mammalian genome : official journal of the International Mammalian Genome Society, 31(9-12):295-308.

Antibiotics contribute a lot to human beings and can kill bacteria effectively. However, more and more studies show that antibiotics can disturb the intestinal microbial community. It has been widely reported that oral antibiotics can reduce the diversity of intestinal microflora, but the effect of intramuscular injection on intestinal microflora is less studied. In this study, we sequenced the intestinal microflora of mice treated with tetracycline by 16SrRNA method, and found that intramuscular injection of tetracycline (TET) can also reduce the intestinal microbial richness of mice. In addition, the results showed that within a certain range (3 mg), with the increase of TET injection concentration, the wind of intestinal microflora in mice decreased significantly. When the injection concentration reached saturation, although the amount of TET injection was increased, the degree of intestinal flora affected was not increased. The results showed that the degree of diversity decrease was in direct proportion to the amount of tetracycline injection in the saturated concentration, but not positively related to the high amount of TET injection after exceeding the saturated concentration.

RevDate: 2021-08-20
CmpDate: 2021-08-20

Zhang H, Wang Q, Zhao J, et al (2020)

Quantitative microbiome profiling links microbial community variation to the intestine regeneration rate of the sea cucumber Apostichopus japonicus.

Genomics, 112(6):5012-5020.

The intestinal microbiota may play important roles in regenerating intestine of the sea cucumber Apostichopus japonicus, the underlying mechanism remains unclear. In the present study, a germ-free sea cucumber model was developed, and the intestinal microbial differentiation of faster and slower regenerating A. japonicus individuals during intestine regeneration was analyzed. The results revealed that depletion of the intestinal microbiota resulted in elevated abundance of the potential key players Flavobacteriaceae and Rhodobacteraceae during intestine regeneration and thus promoted the intestine regeneration rate of A. japonicus. Metagenomic analysis revealed that the increased abundance of Flavobacteriaceae elevated the enrichment of genes associated with carbohydrate utilization, whereas the abundant Rhodobacteraceae-enriched genes were associated with polyhydroxybutyrate production. We identified microbiota abundance as a key driver of microbial community alterations, especially beneficial microbiota members, in the developing intestine of A. japonicus. This study provides new insights into the mechanism of host-microbiota interactions related to organ regeneration.

RevDate: 2021-08-20
CmpDate: 2021-08-20

Kovtun AS, Averina OV, Alekseeva MG, et al (2020)

Antibiotic Resistance Genes in the Gut Microbiota of Children with Autistic Spectrum Disorder as Possible Predictors of the Disease.

Microbial drug resistance (Larchmont, N.Y.), 26(11):1307-1320.

The gut microbiota (GM), which contains thousands of bacterial species, is a reservoir of antibiotic resistance genes (ARGs) called resistome. Early life exposure to antibiotics alters significantly the composition and function of the gut microbiota of children, which may trigger symptoms of autism spectrum disorder (ASD). This is because the GM plays an important role in the bidirectional communication between the gut and the brain and influences the brain normal functioning through multiple pathways. The goal of this article is to study the distribution of ARGs in the GM of 3- to 5-year-old healthy children and children with ASD living in Moscow, Russia. The metagenomic analysis of samples from both groups revealed differences in the signatures between them. The signatures consisted of the bacterial genera and aminoglycoside, β-lactam, macrolide, and tetracycline resistance genes that they harbored. Our results show an increase in ARGs in the resistome of the GM of children with ASD. These findings emphasize the negative influence of early-life antibiotic therapy. We found three ARGs, aac(6')-aph(2''), cepA-49, and tet(40), which could serve as markers of ASD. The additional functions carried out by the enzymes, encoded by these genes, are being discussed.

RevDate: 2021-08-19

Xue CX, Lin H, Zhu XY, et al (2021)

DiTing: A Pipeline to Infer and Compare Biogeochemical Pathways From Metagenomic and Metatranscriptomic Data.

Frontiers in microbiology, 12:698286.

Metagenomics and metatranscriptomics are powerful methods to uncover key micro-organisms and processes driving biogeochemical cycling in natural ecosystems. Databases dedicated to depicting biogeochemical pathways (for example, metabolism of dimethylsulfoniopropionate (DMSP), which is an abundant organosulfur compound) from metagenomic/metatranscriptomic data are rarely seen. Additionally, a recognized normalization model to estimate the relative abundance and environmental importance of pathways from metagenomic and metatranscriptomic data has not been organized to date. These limitations impact the ability to accurately relate key microbial-driven biogeochemical processes to differences in environmental conditions. Thus, an easy-to-use, specialized tool that infers and visually compares the potential for biogeochemical processes, including DMSP cycling, is urgently required. To solve these issues, we developed DiTing, a tool wrapper to infer and compare biogeochemical pathways among a set of given metagenomic or metatranscriptomic reads in one step, based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) and a manually created DMSP cycling gene database. Accurate and specific formulae for over 100 pathways were developed to calculate their relative abundance. Output reports detail the relative abundance of biogeochemical pathways in both text and graphical format. DiTing was applied to simulated metagenomic data and resulted in consistent genetic features of simulated benchmark genomic data. Subsequently, when applied to natural metagenomic and metatranscriptomic data from hydrothermal vents and the Tara Ocean project, the functional profiles predicted by DiTing were correlated with environmental condition changes. DiTing can now be confidently applied to wider metagenomic and metatranscriptomic datasets, and it is available at https://github.com/xuechunxu/DiTing.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Wang M, Sun Y, Zeng Z, et al (2021)

Metagenomics of wastewater phageome identifies an extensively cored antibiotic resistome in a swine feedlot water treatment environment.

Ecotoxicology and environmental safety, 222:112552.

Huge number of antibiotic resistance genes (ARGs) have been widely detected in phage genomes from anthropogenic environment or animal farms, whereas little is known about the dynamic changes of phage contribution to resistance under a feedlot wastewater treatment facility (WTF) pressure. Here, a metagenomics method was used to characterize the sewage phageome and identifies the antibiotic resistome. The results showed that the phage families of Siphoviridae, Myoviridae, and Podoviridae were always the most dominant. Analysis of ARGs carried by bacterial and phages showed that MLS and tetracycline resistance genes always had the highest abundances and the other ARG types also have a fixed hierarchy, showing that there is no significant change in overall ARGs abundance distribution. However, an extensively cored antibiotic resistome were specifically identified in aerobic environment. ARGs encoding ribosomal protection proteins, especially for the ARG subtypes lsaE, tet44, tetM, tetP, macB, MdlB and rpoB2, were more inclined to be selected by phages, suggesting that a more refined mechanism, such as specialized transduction and lateral transduction, was probably involved. In all, these results suggest that monitoring of dynamic changes of phage contribution to resistance should be given more attention and ARGs-carrying phage management should focus on using technologies for controlling cored ARGs rather than only the overall distribution of ARGs in phages.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Matsushita M, Fujita K, Motooka D, et al (2021)

The gut microbiota associated with high-Gleason prostate cancer.

Cancer science, 112(8):3125-3135.

We have found that intestinal bacteria and their metabolites, short-chain fatty acids (SCFAs), promote cancer growth in prostate cancer (PCa) mouse models. To clarify the association between gut microbiota and PCa in humans, we analyzed the gut microbiota profiles of men with suspected PCa. One hundred and fifty-two Japanese men undergoing prostate biopsies (96 with cancer and 56 without cancer) were included in the study and randomly divided into two cohorts: a discovery cohort (114 samples) and a test cohort (38 samples). The gut microbiota was compared between two groups, a high-risk group (men with Grade group 2 or higher PCa) and a negative + low-risk group (men with negative biopsy or Grade group 1 PCa), using 16S rRNA gene sequencing. The relative abundances of Rikenellaceae, Alistipes, and Lachnospira, all SCFA-producing bacteria, were significantly increased in high-risk group. In receiver operating characteristic curve analysis, the index calculated from the abundance of 18 bacterial genera which were selected by least absolute shrinkage and selection operator regression detected high-risk PCa in the discovery cohort with higher accuracy than the prostate specific antigen test (area under the curve [AUC] = 0.85 vs 0.74). Validation of the index in the test cohort showed similar results (AUC = 0.81 vs 0.67). The specific bacterial taxa were associated with high-risk PCa. The gut microbiota profile could be a novel useful marker for the detection of high-risk PCa and could contribute to the carcinogenesis of PCa.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Gil P, Dupuy V, Koual R, et al (2021)

A library preparation optimized for metagenomics of RNA viruses.

Molecular ecology resources, 21(6):1788-1807.

Our understanding of the viral communities associated to animals has not yet reached the level attained on the bacteriome. This situation is due to, among others, technical challenges in adapting metagenomics using high-throughput sequencing to the study of RNA viromes in animals. Although important developments have been achieved in most steps of viral metagenomics, there is yet a key step that has received little attention: the library preparation. This situation differs from bacteriome studies in which developments in library preparation have largely contributed to the democratisation of metagenomics. Here, we present a library preparation optimized for metagenomics of RNA viruses from insect vectors of viral diseases. The library design allows a simple PCR-based preparation, such as those routinely used in bacterial metabarcoding, that is adapted to shotgun sequencing as required in viral metagenomics. We first optimized our library preparation using mock viral communities and then validated a full metagenomic approach incorporating our preparation in two pilot studies with field-caught insect vectors; one including a comparison with a published metagenomic protocol. Our approach provided a fold increase in virus-like sequences compared to other studies, and nearly-full genomes from new virus species. Moreover, our results suggested conserved trends in virome composition within a population of a mosquito species. Finally, the sensitivity of our approach was compared to a commercial diagnostic PCR for the detection of an arbovirus in field-caught insect vectors. Our approach could facilitate studies on viral communities from animals and the democratization of metagenomics in community ecology of viruses.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Fishbein SRS, Hink T, Reske KA, et al (2021)

Randomized Controlled Trial of Oral Vancomycin Treatment in Clostridioides difficile-Colonized Patients.

mSphere, 6(1):.

Clostridioides difficile infection (CDI) is most commonly diagnosed using nucleic acid amplification tests (NAAT); the low positive predictive value of these assays results in patients colonized with C. difficile unnecessarily receiving CDI treatment antibiotics. The risks and benefits of antibiotic treatment in individuals with such cases are unknown. Fecal samples of NAAT-positive, toxin enzyme immunoassay (EIA)-negative patients were collected before, during, and after randomization to vancomycin (n = 8) or placebo (n = 7). C. difficile and antibiotic-resistant organisms (AROs) were selectively cultured from fecal and environmental samples. Shotgun metagenomics and comparative isolate genomics were used to understand the impact of oral vancomycin on the microbiome and environmental contamination. Overall, 80% of placebo patients and 71% of vancomycin patients were colonized with C. difficile posttreatment. One person randomized to placebo subsequently received treatment for CDI. In the vancomycin-treated group, beta-diversity (P = 0.0059) and macrolide-lincosamide-streptogramin (MLS) resistance genes (P = 0.037) increased after treatment; C. difficile and vancomycin-resistant enterococci (VRE) environmental contamination was found in 53% of patients and 26% of patients, respectively. We found that vancomycin alters the gut microbiota, does not permanently clear C. difficile, and is associated with VRE colonization/environmental contamination. (This study has been registered at ClinicalTrials.gov under registration no. NCT03388268.)IMPORTANCE A gold standard diagnostic for Clostridioides difficile infection (CDI) does not exist. An area of controversy is how to manage patients whose stool tests positive by nucleic acid amplification tests but negative by toxin enzyme immunoassay. Existing data suggest most of these patients do not have CDI, but most are treated with oral vancomycin. Potential benefits to treatment include a decreased risk for adverse outcomes if the patient does have CDI and the potential to decrease C. difficile shedding/transmission. However, oral vancomycin perturbs the intestinal microbiota and promotes antibiotic-resistant organism colonization/transmission. We conducted a double-blinded randomized controlled trial to assess the risk-benefit of oral vancomycin treatment in this population. Oral vancomycin did not result in long-term clearance of C. difficile, perturbed the microbiota, and was associated with colonization/shedding of vancomycin-resistant enterococci. This work underscores the need to better understand this population of patients in the context of C. difficile/ARO-related outcomes and transmission.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Hashimoto K, Yamazaki F, Kohyama N, et al (2020)

Analysis of Fungal Flora in the Dust of Bedding in Japanese Houses and Genetic Identification of Yeasts Isolated from the Dust.

Biocontrol science, 25(4):193-202.

This study examined the fungal flora contained in the dust of bedding used in 50 houses in Japan. The result showed that the mycoflora having the largest isolation rate was yeasts, which were isolated by 42 out of 50 houses (84%), and exceeded the isolation rate of Cladosporium spp. (80%) and Aspergillus spp. (66%). In addition, the isolation rate of Alternaria, which was an important fungus causing asthma, 66% was being considered as a high isolation rate, and this result was very interesting. The isolation rate of xerophilic fungi such as Aspergillus restrictus and Wallemia often found in house dust on the floor, was not very high. Forty-one strains of yeasts isolated from each dust sample were identified, and Naganishia diffluens species complex and Filobasidium magnum had a larger number of 13 strains, respectively. Since N. diffluens was the yeasts often isolated from human skin, it was thought to be an association between the fungal skin flora and fungal flora of bed dust. Meanwhile, there was no report of isolation of F. magnum from house dust previously. To the best of our knowledge, this is the first study showing its isolation from bedding with relatively high frequency.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Berggrund M, Gustavsson I, Aarnio R, et al (2020)

Temporal changes in the vaginal microbiota in self-samples and its association with persistent HPV16 infection and CIN2.

Virology journal, 17(1):147.

BACKGROUND: The vaginal microbiota has been reported to be associated with HPV infection and cervical cancer. This study was performed to compare the vaginal microbiota at two timepoints in women performing self-sampling and had a persistent or transient HPV16 infection. The women were tested for 12 high-risk HPV (hrHPV) types but only women with single type (HPV16) were included to reduce confounding variables.

METHODS: In total 96 women were included in this study. Of these, 26 were single positive for HPV16 in the baseline test and HPV negative in the follow-up test and 38 were single positive for HPV16 in both tests and diagnosed with CIN2+ in histology. In addition, 32 women that were negative for all 12 HPV tested were included. The samples of vaginal fluid were analyzed with the Ion 16S™ Metagenomics Kit and Ion 16S™ metagenomics module within the Ion Reporter™ software.

RESULTS: K-means clustering resulted in two Lactobacillus-dominated groups, one with Lactobacillus sp. and the other specifically with Lactobacillus iners. The two remaining clusters were dominated by a mixed non-Lactobacillus microbiota. HPV negative women had lower prevalence (28%) of the non-Lactobacill dominant cluster in the baseline test, as compared to women with HPV16 infection (42%) (p value = 0.0173). Transition between clusters were more frequent in women with persistent HPV16 infection (34%) as compared in women who cleared the HPV16 infection (19%) (p value = 0.036).

CONCLUSIONS: The vaginal microbiota showed a higher rate of transitioning between bacterial profiles in women with persistent HPV16 infection as compared to women with transient infection. This indicate an instability in the microenvironment in women with persistent HPV infection and development of CIN2+.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Hoque MN, Istiaq A, Rahman MS, et al (2020)

Microbiome dynamics and genomic determinants of bovine mastitis.

Genomics, 112(6):5188-5203.

The milk of lactating cows presents a complex ecosystem of interconnected microbial communities which can influence the pathophysiology of mastitis. We hypothesized possible dynamic shifts of microbiome composition and genomic features with different pathological conditions of mastitis (Clinical Mastitis; CM, Recurrent CM; RCM, Subclinical Mastitis; SCM). To evaluate this hypothesis, we employed whole metagenome sequencing (WMS) in 20 milk samples (CM, 5; RCM, 6; SCM, 4; H, 5) to unravel the microbiome dynamics, interrelation, and relevant metabolic functions. The WMS data mapped to 442 bacterial, 58 archaeal and 48 viral genomes with distinct variation in microbiome composition (CM > H > RCM > SCM). Furthermore, we identified a number of microbial genomic features, including 333, 304, 183 and 50 virulence factors-associated genes (VFGs) and 48, 31, 11 and 6 antibiotic resistance genes (ARGs) in CM, RCM, SCM, and H-microbiomes, respectively. We also detected different metabolic pathway and functional genes associated with mastitis pathogenesis. Therefore, profiling microbiome dynamics in different conditions of mastitis and associated microbial genomic features contributes to developing microbiome-based diagnostics and therapeutics for bovine mastitis.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Ryan MJ, Schloter M, Berg G, et al (2021)

Development of Microbiome Biobanks - Challenges and Opportunities.

Trends in microbiology, 29(2):89-92.

The microbiome research field is rapidly evolving, but the required biobanking infrastructure is currently fragmented and not prepared for the biobanking of microbiomes. The rapid advancement of technologies requires an urgent assessment of how biobanks can underpin research by preserving microbiome samples and their functional potential.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Khan Mirzaei M, Xue J, Costa R, et al (2021)

Challenges of Studying the Human Virome - Relevant Emerging Technologies.

Trends in microbiology, 29(2):171-181.

In this review we provide an overview of current challenges and advances in bacteriophage research within the growing field of viromics. In particular, we discuss, from a human virome study perspective, the current and emerging technologies available, their limitations in terms of de novo discoveries, and possible solutions to overcome present experimental and computational biases associated with low abundance of viral DNA or RNA. We summarize recent breakthroughs in metagenomics assembling tools and single-cell analysis, which have the potential to increase our understanding of phage biology, diversity, and interactions with both the microbial community and the human body. We expect that these recent and future advances in the field of viromics will have a strong impact on how we develop phage-based therapeutic approaches.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Carr VR, Shkoporov A, Hill C, et al (2021)

Probing the Mobilome: Discoveries in the Dynamic Microbiome.

Trends in microbiology, 29(2):158-170.

There has been an explosion of metagenomic data representing human, animal, and environmental microbiomes. This provides an unprecedented opportunity for comparative and longitudinal studies of many functional aspects of the microbiome that go beyond taxonomic classification, such as profiling genetic determinants of antimicrobial resistance, interactions with the host, potentially clinically relevant functions, and the role of mobile genetic elements (MGEs). One of the most important but least studied of these aspects are the MGEs, collectively referred to as the 'mobilome'. Here we elaborate on the benefits and limitations of using different metagenomic protocols, discuss the relative merits of various sequencing technologies, and highlight relevant bioinformatics tools and pipelines to predict the presence of MGEs and their microbial hosts.

RevDate: 2021-08-19
CmpDate: 2021-08-19

Bender JM, Li F, Purswani H, et al (2021)

Early exposure to antibiotics in the neonatal intensive care unit alters the taxonomic and functional infant gut microbiome.

The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, 34(20):3335-3343.

INTRODUCTION: The infant gut microbiome is thought to play a key role in developing metabolic and immunologic pathways. Antibiotics have been shown to disrupt the human microbiome, but the impact they have on infants during this key window of development remains poorly understood. Through this study, we further characterize the effect antibiotics have on the gut microbiome of infants by looking at metagenomic sequencing data over time.

MATERIALS AND METHODS: Stool samples were collected on infants from a large tertiary care neonatal intensive care unit. After DNA extraction, metagenomics libraries were generated and sequenced. Taxonomic and functional analyses were then performed. Further directed specimen sequencing for fungal species was also performed.

RESULTS: A total of 51 stool samples from 25 infants were analyzed: seven infants were on antibiotics during at least one of their collection time points. Antibiotics given at birth altered the microbiome (PERMANOVA R2 = 0.044, p = .002) but later courses did not (R2 = 0.023, p = .114). Longitudinal samples collected while off antibiotics were more similar than those collected during a transition on or off antibiotics (mean Bray-Curtis distance 0.29 vs. 0.63, Wilcoxon p = .06). Functional analysis revealed four microbial pathways that were disrupted by antibiotics given at-birth (p < .1, folate synthesis, glycerolipid metabolism, fatty acid biosynthesis, and glycolysis). No functional changes associated with current antibiotic use were identified. In a limited sample set, we saw little evidence of fungal involvement in the overall infant microbiome.

CONCLUSION: Through this study, we have further characterized the role antibiotics have in the development of the infant microbiome. Antibiotics given at birth were associated with alterations in the microbiome and had significant impact on the functional pathways involved in folate synthesis and multiple metabolic pathways. Later courses of antibiotics led to stochastic dysbiosis and a significant decrease in Escherichia coli. Further characterization of the infant mycobiome is still needed.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Zhang L, Gong X, Wang L, et al (2021)

Metagenomic insights into the effect of thermal hydrolysis pre-treatment on microbial community of an anaerobic digestion system.

The Science of the total environment, 791:148096.

Thermal hydrolysis process (THP) is an effective pre-treatment method to reduce solids volume and improve biogas production during anaerobic digestion (AD) via increasing the biodegradability of waste activated sludge (WAS). However, the effects of THP pre-treated sludge on microbial diversity, interspecies interactions, and metabolism in AD systems remain largely unknown. We therefore setup and operated an anaerobic digester during a long-term period to shed light on the effect of THP pre-treatment on AD microbial ecology in comparison to conventional AD via Illumina based 16S rRNA gene amplicon sequencing and genome-centric metagenomics analysis. Results showed THP sludge significantly reduced the microbial diversity, shaped the microbial community structure, and resulted in more intense microbial interactions. Compared to WAS as the feed sludge, THP sludge shaped the core functional groups, but functional redundancy ensured the system's stability. The metabolic interactions between methanogens and syntrophic bacteria as well as the specific metabolic pathways were further elucidated. Hydrogenotrophic methanogens, Methanospirillum sp. and Methanolinea sp., were the primary contributors for methane production when treating THP and WAS, respectively, which also have potential for acetate oxidation to methane. Collectively, this study provides in-depth information on the interspecies interactions to better understand how THP pre-treatment influences AD microbial community.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Alanin KWS, Junco LMF, Jørgensen JB, et al (2021)

Metaviromes Reveal the Dynamics of Pseudomonas Host-Specific Phages Cultured and Uncultured by Plaque Assay.

Viruses, 13(6):.

Isolating single phages using plaque assays is a laborious and time-consuming process. Whether single isolated phages are the most lyse-effective, the most abundant in viromes, or those with the highest ability to make plaques in solid media is not well known. With the increasing accessibility of high-throughput sequencing, metaviromics is often used to describe viruses in environmental samples. By extracting and sequencing metaviromes from organic waste with and without exposure to a host-of-interest, we show a host-related phage community's shift, as well as identify the most enriched phages. Moreover, we isolated plaque-forming single phages using the same virome-host matrix to observe how enrichments in liquid media correspond to the metaviromic data. In this study, we observed a significant shift (p = 0.015) of the 47 identified putative Pseudomonas phages with a minimum twofold change above zero in read abundance when adding a Pseudomonas&nbsp;syringae DC3000 host. Surprisingly, it appears that only two out of five plaque-forming phages from the same organic waste sample, targeting the Pseudomonas strain, were highly abundant in the metavirome, while the other three were almost absent despite host exposure. Lastly, our sequencing results highlight how long reads from Oxford Nanopore elevates the assembly quality of metaviromes, compared to short reads alone.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Muturi EJ, Njoroge TM, Dunlap C, et al (2021)

Blood meal source and mixed blood-feeding influence gut bacterial community composition in Aedes aegypti.

Parasites & vectors, 14(1):83.

BACKGROUND: The guts of blood-sucking insects host a community of bacteria that can shift dramatically in response to biotic and abiotic factors. Identifying the key factors structuring these microbial communities has important ecological and epidemiological implications.

METHODS: We used the yellow fever mosquito, Aedes aegypti, to investigate the impact of mixed blood meals on gut microbiota of vector mosquitoes. Adult females were experimentally fed on sugar or blood from chicken, rabbit or a mixture of chicken and rabbit blood, and their gut microbiota were characterized using 16S rRNA gene amplification and MiSeq sequencing.

RESULTS: The gut bacterial communities of mosquitoes fed on the three blood meal treatments clustered separately, suggesting that host species identity and mixed blood-feeding are key determinants of gut bacterial community composition in mosquitoes. Mixed blood meal had a synergistic effect on both operational taxonomic unit (OTU) richness and the Shannon diversity index, suggesting that mixed blood-feeding can offset the nutritional deficit of blood meals from certain host species. The microbial communities observed in this study were distinct from those identified from similarly fed Ae. aegypti from our previous study.

CONCLUSIONS: These findings demonstrate that vector host-feeding preferences can influence gut microbial composition and diversity, which could potentially impact pathogen acquisition and transmission by the vector. The results also demonstrate that different microenvironmental conditions within the laboratory may play an important role in structuring the microbial communities of independently reared mosquito colonies.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Fadiji AE, Ayangbenro AS, OO Babalola (2021)

Unveiling the putative functional genes present in root-associated endophytic microbiome from maize plant using the shotgun approach.

Journal of applied genetics, 62(2):339-351.

To ensure food security for the ever-increasing world's population, it is important to explore other alternatives for enhancing plant productivity. This study is aimed at identifying the putative plant growth-promoting (PGP) and endophytic gene clusters in root-associated endophytic microbes from maize root and to also verify if their abundance is affected by different farming practices. To achieve this, we characterize endophytic microbiome genes involved in PGP and endophytic lifestyle inside maize root using the shotgun metagenomic approach. Our results revealed the presence of genes involved in PGP activities such as nitrogen fixation, HCN biosynthesis, siderophore, 4-hydroxybenzoate, ACC deaminase, phenazine, phosphate solubilization, butanediol, methanol utilization, acetoin, nitrogen metabolism, and IAA biosynthesis. We also identify genes involved in stress resistance such as glutathione, catalase, and peroxidase. Our results further revealed the presence of putative genes involved in endophytic behaviors such as aerotaxis, regulator proteins, motility mechanisms, flagellum biosynthesis, nitrogen regulation, regulation of carbon storage, formation of biofilm, reduction of nitric oxide, regulation of beta-lactamase resistance, type III secretion, type IV conjugal DNA, type I pilus assembly, phosphotransferase system (PTS), and ATP-binding cassette (ABC). Our study suggests a high possibility in the utilization of endophytic microbial community for plant growth promotion, biocontrol activities, and stress mitigation. Further studies in ascertaining this claim through culturing of the beneficial isolates as well as pot and field experiments are necessary.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Tiew PY, Jaggi TK, Chan LLY, et al (2021)

The airway microbiome in COPD, bronchiectasis and bronchiectasis-COPD overlap.

The clinical respiratory journal, 15(2):123-133.

OBJECTIVE: To review the airway microbiome in chronic obstructive pulmonary disease (COPD), bronchiectasis and bronchiectasis-COPD overlap (BCO).

Relevant studies were selected from PubMed, Google scholar, EMBASE and Web of Science. All studies involving human microbiomes, published in the English language, and using the search terms "COPD", "Chronic Obstructive Pulmonary Disease", "Bronchiectasis", "BCO" or "Bronchiectasis and COPD overlap", AND "microbiome", "mycobiome" or "metagenomics" were included.

RESULTS: Despite variability in sampling methods and specimen types used, microbiome composition remains relatively comparable in COPD and bronchiectasis with prominence of Proteobacteria, Firmicutes and Bacteroidetes. Alterations to airway microbiomes occur in association to disease severity and/or exacerbations in COPD and bronchiectasis. Decreased alpha diversity and Haemophilus-predominant microbiomes are associated with poorer survival in COPD, while, in bronchiectasis, Pseudomonas-predominant microbiomes demonstrate high exacerbation frequency and greater symptom burden while Aspergillus-dominant mycobiome profiles associate with exacerbations. The role of the microbiome in BCO remains understudied.

CONCLUSION: Use of next-generation sequencing has revolutionised our detection and understanding of the airway microbiome in chronic respiratory diseases such as COPD and bronchiectasis. Targeted amplicon sequencing reveals important associations between the respiratory microbiome and disease outcome while metagenomics may elucidate functional pathways. How best to apply this information into patient care, monitoring and treatment, however, remains challenging and necessitates further study.

RevDate: 2021-08-18
CmpDate: 2021-08-18

Urban RJ, Pyles RB, Stewart CJ, et al (2020)

Altered Fecal Microbiome Years after Traumatic Brain Injury.

Journal of neurotrauma, 37(8):1037-1051.

Patients with chronic traumatic brain injury (TBI) requiring long-term, permanent care suffer a myriad of clinical symptoms (i.e., impaired cognition, fatigue, and other conditions) that persist for years beyond the acute brain injury. In addition to these comorbid clinical symptoms, chronic TBI patients exhibit altered amino acid and hormonal profiles with distinct cytokine patterns suggesting chronic inflammation. This metabolic link suggests a role of the gut-brain axis in chronic TBI. Thus, we utilized a two-site trial to investigate the role of the gut-brain axis in comorbidities of chronic TBI. The fecal microbiome profile of 22 moderate/severe TBI patients residing in permanent care facilities in Texas and California was compared to 18 healthy age-matched control subjects working within the participating facilities. Each fecal microbiome was characterized by 16S(V4) ribosomal RNA (rRNA) gene sequencing and metagenomic genome sequencing approaches followed by confirmatory full 16S rRNA gene sequencing or focused tuf gene speciation and specific quantitative polymerase chain reaction evaluation of selected genera or species. The average chronic TBI patient fecal microbiome structure was significantly different compared to the control cohort, and these differences persisted after group stratification analysis to identify any unexpected confounders. Notably, the fecal microbiome of the chronic TBI cohort had absent or reduced Prevotella spp. and Bacteroidies spp. Conversely, bacteria in the Ruminococcaceae family were higher in abundance in TBI compared to control profiles. Previously reported hypoaminoacidemia, including significantly reduced levels of l-tryptophan, l-sarcosine, ß-alanine, and alanine, positively correlated with the reduced levels of Prevotella spp. in the TBI cohort samples compared to controls. Although the sequelae of gut-brain axis disruption after TBI is not fully understood, characterizing TBI-related alterations in the fecal microbiome may provide biomarkers and therapeutic targets to address patient morbidity.

RevDate: 2021-08-17
CmpDate: 2021-08-17

Ruscheweyh HJ, Milanese A, Paoli L, et al (2021)

mOTUs: Profiling Taxonomic Composition, Transcriptional Activity and Strain Populations of Microbial Communities.

Current protocols, 1(8):e218.

The mOTU profiler, or mOTUs for short, is a software tool that enables the profiling of microbial communities in terms of their taxonomic composition, relative abundance of metabolically active members, and diversity of strain populations. To this end, it maintains a database of single-copy phylogenetic marker gene sequences, which are used as a reference to which short read metagenomic and metatranscriptomic reads are mapped for the identification and quantification of microbial taxa. Here, we describe the most common use cases of the mOTU profiler in two basic protocols. Additional supporting protocols provide information on its installation and in-depth guidance on adjusting its settings for increasing or decreasing the stringency with which taxa are detected and quantified, as well as for customizing the output file format. Guidelines for understanding the profiling results are provided, along with additional information on unique features, methodological details, and the development history of the tool. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Metagenomic and metatranscriptomic mOTU profiling Basic Protocol 2: Metagenomic SNV profiling Support Protocol 1: Installing mOTUs Support Protocol 2: Profiling pipeline-step by step Support Protocol 3: The mOTUs profiling routine using advanced parameters Support Protocol 4: Metagenomic SNV calling: advanced parameters.

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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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