Project description:We aim to study the unusual TMA metabolism mechanism of ducks, and further explore the hidden reasons that led to the weakening TMA metabolism ability. To achieve this, transcriptome, proteome, and metagenome analyses were integrated based on the constructed duck populations with high TMA metabolism ability and low TMA metabolism ability. In addition, further experiments were followed to validate the hypothesis on the limited flavin-containing monooxygenase 3 (FMO3) metabolism ability of ducks. The study demonstrated that both cecal microbe, including Akkermansia and Mucispirillum, and liver FMO3 participated in the TMA metabolism process of ducks. The limited oxidation ability of FMO3 explained the weakening TMA metabolism ability of ducks. Nevertheless, it contributed to the duck’s survival and reproduction during the evolutional adaption process.
Project description:We aim to study the unusual TMA metabolism mechanism of ducks, and further explore the hidden reasons that led to the weakening TMA metabolism ability.To achieve this, transcriptome, proteome, and metagenome analyses were integrated based on the constructed duck populations with high TMA metabolism ability and low TMA metabolism ability.
Project description:Improper use of antibiotics in swine could reduce commensal bacteria and possibly increase pathogen infections via the gut resistome. This study aimed to compare the metaproteomic profiles of gut resistome and related metabolism in the cecal microbiota of fattening pigs raised under antibiotic-free (ABF) conditions with those of ordinary industrial pigs (CTRL).
Project description:This study in rats was designed to investigate whether whole rhye (WR) can influence the metabolism of n-3 and n-6 long-chain fatty acids (LCFA) and gut microbiota composition. For 12 weeks, rats were fed a diet containing either 50% WR or 50% refined rye (RR). Total bacterial DNA was extracted from fecal and cecal samples (n=5 per group). 16S PCR amplification was performed to assess the microbial diversity at the family level using the HuGChip. Amplified DNA was purified and labelled with either Cy3 or Cy5 dye and hybridized on the microarray. A 15 chip study was realized, each corresponding to hybridization with 250ng of labelled 16S rRNA gene amplicons from either mice fecal and cecal samples. Each probe (4441) was synthetized in three replicates.
Project description:Trimethylamine (TMA) is an important gut microbial metabolite strongly associated with human disease. There are prominent gaps in our understanding of how TMA is produced from the essential dietary nutrient L-carnitine, particularly in the anoxic environment of the human gut where oxygen-dependent L-carnitine-metabolizing enzymes are likely inactive. Here, we elucidate the chemical and genetic basis for anaerobic TMA generation from the L-carnitine-derived metabolite γ-butyrobetaine (γbb) by the human gut bacterium Emergencia timonensis. We identify a set of genes upregulated by γbb and demonstrate that the enzymes encoded by the induced γbb utilization (bbu) gene cluster convert γbb to TMA. The key TMA-generating step is catalyzed by a previously unknown type of TMA-lyase enzyme that utilizes a flavin cofactor to catalyze a redox neutral transformation. We identify additional cultured and uncultured host-associated bacteria that possess the bbu gene cluster, providing insights into the distribution of anaerobic γbb metabolism. Lastly, we present genetic, transcriptional, and metabolomic evidence that confirms the relevance of this metabolic pathway in the human gut microbiota. These analyses indicate that the anaerobic pathway is a more substantial contributor to TMA generation from L-carnitine in the human gut than the previously proposed aerobic pathway. The discovery and characterization of the bbu pathway provides the critical missing link in anaerobic metabolism of L-carnitine to TMA, enabling investigation into the connection between this microbial function and human disease.
Project description:Abdominal fat deposition is an important trait in meat-producing ducks. F2 generations of 304 Cherry Valley and Runzhou Crested White ducks were studied to identify genes and lncRNAs affecting abdominal fat deposition. RNA sequencing was used to study abdominal fat tissue of four ducks each with high or low abdominal fat rates. In all, 336 upregulated and 297 downregu-lated mRNAs, and 95 upregulated and 119 downregulated lncRNAs were identified. Target gene prediction of differentially expressed lncRNAs identified 602 genes that were further subjected to Gene Ontology and KEGG pathway analysis. The target genes were enriched in pathways associ-ated with fat synthesis and metabolism and participated in biological processes, including Linoleic acid metabolism, lipid storage, and fat cell differentiation, indicating that these lncRNAs play an important role in abdominal fat deposition. This study lays foundations for exploring molecu-lar mechanisms underlying the regulation of abdominal fat deposition in ducks and provides a theoretical basis for breeding high-quality meat-producing ducks.
Project description:Choline is a water-soluble nutrient essential for human life. Gut microbial metabolism of choline results in the production of trimethylamine (TMA), which upon absorption by the host is converted in the liver to trimethylamine N-oxide (TMAO). Recent studies revealed that TMAO exacerbates atherosclerosis in mice, and positively correlates with the severity of this disease in human. However, which microbes contribute to TMA production in the human gut; the extent to which host factors, e.g., genotype and diet, affect TMA production and colonization of these microbes; as well as the effects TMA-producing microbes have on bioavailability of dietary choline remain largely unknown. We screened a collection of 78 sequenced human intestinal isolates encompassing the major phyla found in the human gut and identified eight strains capable of producing TMA from choline in vitro. Gnotobiotic mouse studies showed that TMAO accumulates in the serum of animals colonized with TMA-producing species, but not in the serum of animals colonized with intestinal isolates that do not generate TMA from choline in vitro. Remarkably, low levels of colonization of TMA-producing bacteria significantly reduced choline levels available to the host. This effect was more pronounced as the abundance of TMA-producing bacteria increased. Our findings provide a framework for designing strategies aimed at changing the representation or activity of TMA-producing bacteria in the human gut and suggest the TMA producing status of the gut microbiota should be considered when making recommendations about choline intake requirements for humans.
Project description:BACKGROUND & AIMS: There is mounting evidence that microbes resident in the human intestine contribute to diverse alcohol-associated liver diseases (ALD) including the most deadly form known as alcoholic hepatitis (AH). However, mechanisms by which gut microbiota synergize with excessive alcohol intake to promote liver injury are poorly understood. Furthermore, whether drugs that selectively target gut microbial metabolism can improve ALD has never been tested. METHODS: We used liquid chromatography tandem mass spectrometry to quantify the levels of microbe and host choline co-metabolites in healthy controls and AH patients, and identified the metabolite trimethylamine (TMA) as a gut microbe-derived biomarker of AH. In subsequent studies, we treated mice with non-lethal mechanism-based bacterial choline TMA lyase inhibitors to blunt gut microbe-dependent production of TMA in the context of chronic ethanol administration. Indices of liver injury were quantified by complementary RNA sequencing, biochemical, and histological approaches. In addition, we examined the impact of ethanol consumption and TMA lyase inhibition on gut microbiome structure via 16S rRNA sequencing. RESULTS: We show the gut microbial choline metabolite trimethylamine (TMA) is elevated in AH patients, which is correlated with reduced hepatic expression of the TMA oxygenase flavin-containing monooxygenase 3 (FMO3). Provocatively, we find that small molecule inhibition of gut microbial choline TMA lyase activity protects mice from ethanol-induced liver injury. TMA lyase inhibitor-driven improvement in ethanol-induced liver injury is associated with distinct reorganization of the gut microbiome community and host liver transcriptome. CONCLUSIONS: The microbial metabolite TMA is a biomarker of AH, and blocking TMA production from gut microbes can blunt ALD in mice.
Project description:We compared gene expression in the small intestine (ileum) of mice that were either (i) germ-free, (ii) colonized with a conventional mouse cecal microbiota, (iii) colonized with a conventional zebrafish gut microbiota, or (iv) colonized with Pseudomonas aeruginosa PAO1. Experiment Overall Design: Adult germ-free NMRI mice were colonized with either (i) a conventional mouse cecal microbiota harvested from adult Swiss-Webster mice (5 biological replicates), (ii) a conventional zebrafish intestinal microbiota harvested from adult C32 zebrafish (3 biological replicates), or (iii) a culture of Pseudomonas aeruginosa PAO1 (5 biological replicates). 14 days after colonization, total RNA was prepared from the ileum of each animal, with total RNA prepared from adult germ-free NMRI mouse ileum serving as negative controls (5 biological replicates). RNA was used as template to generate cRNA for hybridization to Affymetrix 430 v2 Mouse GeneChips.