Project description:We recruited 24 Mongolian volunteers,6 of which were T2D cases(sample T1-T6), 6 were prediabetes cases(sample P1-P6), and 12 were health cases(sample C1-C12). The metagenomic analysis of gut microbiota from the volunteers’ fecal samples was performed. We compared the microbial differences in the three groups, and analyzed the differences of the stool microbial function.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw. A 2m deep permafrost sample and it overlying active layer were sampled and their metagenome analysed. For microarray analyses, 8 other soil samples from the same region were used for comparison purposes.
Project description:Background: As a worldwide threat to mental health, depression affects about 322 million people globally. Recently, the role of gut microbiota dysbiosis on the pathogenesis of depression has received widespread attention, but the underlying mechanism remains elusive.Results: Corticosterone (CORT)-treated mice showed depressive-like behaviors, a reduction in hippocampal neurogenesis, and an altered composition of gut microbiota (GM). Fecal microbial transplantation (FMT) from CORT-treated mice transferred depressive-like phenotypes and their dominant GM, especially bifidobacterium and lactobacillus, to the recipients. Fecal metabolic profiling showed that the relative abundances of fecal ceramides were significantly increased in CORT-treated and the recipient mice. Metagenomic sequencing exposed that bifidobacterium and lactobacillus might be responsible for gut ceramides production in CORT-treated mice. We then found that treatment with ceramides via oral gavage was sufficient to recapitulate the depressive-like phenotypes in wild -type mice. Finally, RNA-sequencing data exposed that most of the differentially expressed genes (DEGs) between ceramides-treated mice and the control group were enriched in oxidative phosphorylation (OXPHOS) pathway. Conclusion: We conclude that chronic exposure to CORT leads to an altered GM composition and consequent ceramides production, thus leading to subtle mitochondrial OXPHOS dysfunction in hippocampus, which may contribute to the development of depressive disorders.
Project description:Metagenomic sequencing of mice with different treatments: Mice were randomly divided into donor control group (Donor + MRS), constipation model group (STC + MRS), or a Lactobacillus acidophilus treated group (STC + La): A humanized mouse model was established by intragastric administration of fecal bacterial liquid from healthy donors or STC patients on alternate days, followed by continuous administration of Lactobacillus acidophilus in treatment group. Finally, the feces of each group of mice were collected, and the intestinal microbial communities of the mice were analyzed through metagenomic sequencing. 16S rRNA sequencing of mice before and after the use antibiotics: Before and after treating the mice with antibiotics, the mice's feces were collected for 16s rRNA sequencing respectively.
Project description:Distal gut bacteria play a pivotal role in the digestion of dietary polysaccharides by producing a large number of carbohydrate-active enzymes (CAZymes) that the host otherwise does not produce. We report here the design of a high density custom microarray that we used to spot non-redundant DNA probes for more than 6,500 genes encoding glycoside hydrolases and lyases selected from 174 reference genomes from distal gut bacteria. The custom microarray was tested and validated by the hybridization of bacterial DNA extracted from the stool samples of lean, obese and anorexic individuals. Our results suggest that a microarray-based study can detect genes from low-abundance bacteria better than metagenomic-based studies. A striking example was the finding that a gene encoding a GH6-family cellulase was present in all subjects examined, whereas metagenomic studies have consistently failed to detect this gene in both human and animal gut microbiomes. In addition, an examination of eight stool samples allowed the identification of a corresponding CAZome core containing 46 families of glycoside hydrolases and polysaccharide lyases, which suggests the functional stability of the gut microbiota despite large taxonomical variations between individuals. Fecal samples were collected from eight female subjects. Three were obese subjects of BMI kg m-2: 35, 46.8 and 51.3, respectively; age: 42, 21 and 65 years old, respectively. Three were anorexic women of BMI kg m-2: 9.8, 10 and 13.7, respectively; age: 19, 23 and 49 years old, respectively. Finally, two fecal samples from lean women of BMI kg m-2: 18.6 and 23.42 were analyzed.
Project description:<p>Traveler's diarrhea (TD) is caused by enterotoxigenic Escherichia coli (ETEC), other pathogenic gram-negative pathogens, norovirus and some parasites. Nevertheless, standard diagnostic methods fail to identify pathogens in more than 30% of TD patients, so it is predicted that new pathogens or groups of pathogens may be causative agents of disease. A comprehensive metagenomic study of the fecal microbiomes from 23 TD patients and seven healthy travelers was performed, all of which tested negative for the known etiologic agents of TD in standard tests. Metagenomic reads were assembled and the resulting contigs were subjected to semi-manual binning to assemble independent genomes from metagenomic pools. Taxonomic and functional annotations were conducted to assist identification of putative pathogens. We extracted 560 draft genomes, 320 of which were complete enough to be enough characterized as cellular genomes and 160 of which were bacteriophage genomes. We made predictions of the etiology of disease in individual subjects based on the properties and features of the recovered cellular genomes. Three subtypes of samples were observed. First were four patients with low diversity metagenomes that were predominated by one or more pathogenic E. coli strains. Annotation allowed prediction of pathogenic type in most cases. Second, five patients were co-infected with E. coli and other members of the Enterobacteriaceae, including antibiotic resistant Enterobacter, Klebsiella, and Citrobacter. Finally, several samples contained genomes that represented dark matter. In one of these samples we identified a TM7 genome that phylogenetically clustered with a strain isolated from wastewater and carries genes encoding potential virulence factors. We also observed a very high proportion of bacteriophage reads in some samples. The relative abundance of phage was significantly higher in healthy travelers when compared to TD patients. Our results highlight that assembly-based analysis revealed that diarrhea is often polymicrobial and includes members of the Enterobacteriaceae not normally associated with TD and have implicated a new member of the TM7 phylum as a potential player in diarrheal disease. </p>
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw.
Project description:In this study we investigated whether gut microbiota profile of Italian healthy volunteers could differ based on their geaographical origin. To this purpose, fecal samples were collected from 31 healthy individuals living in 3 different italian regions (Lombardy, North; Lazio, Center; Apulia, South) and their respective microbiota profiles were analyzed employing 16S metagenomic sequencing method. This study identifies differences in the gut microbiota content and richness among individuals with the same ethnicity coming from three different Italian regions.