科研之友
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摘要
Recent research has disclosed a tight connection between obesity, metabolic gut microbial activities and host health. Obtaining a complete understanding of this relationship remains a major goal. Here, we conducted a comparative metagenomic and metaproteomic investigation of gut microbial communities in faecal samples taken from an obese and a lean adolescent. By analysing the diversity of 16S rDNA amplicons (10% operational phylogenetic units being common), 22 Mbp of consensus metagenome sequences (similar to 70% common) and the expression profiles of 613 distinct proteins (82% common), we found that in the obese gut, the total microbiota was more abundant on the phylum Firmicutes (94.6%) as compared with Bacteroidetes (3.2%), although the metabolically active microbiota clearly behaves in a more homogeneous manner with both contributing equally. The lean gut showed a remarkable shift towards Bacteroidetes (18.9% total 16S rDNA), which become the most active fraction (81% proteins). Although the two gut communities maintained largely similar gene repertoires and functional profiles, improved pili-and flagella-mediated host colonization and improved capacity for both complementary aerobic and anaerobic de novo B-12 synthesis, 1,2-propanediol catabolism (most likely participating in de novo B-12 synthesis) and butyrate production were observed in the obese gut, whereas bacteria from lean gut seem to be more engaged in vitamin B-6 synthesis. Furthermore, this study provides functional evidence that variable combinations of species from different phyla could %26apos;presumptively%26apos; fulfil overlapping and/or complementary functional roles required by the host, a scenario where minor bacterial taxa seem to be significant active contributors.
- 出版日期2013-1
