• 合作表型是微生物群落功能的核心,肠道菌群的内部合作对其生态系统十分重要;
  • 模型成员拟杆菌B. thetaiotaomicron在某些膳食多糖中生长时表现出有限的合作,其可以在细胞外消化多糖,而无消化能力的突变菌没有竞争能力;
  • 肠道共生的卵形拟杆菌B. ovatus中存在着一种专门的交互共生酶系统,其自身消化多糖,同时对另一种物种有益;
  • B. ovatus细胞外消化菊粉的产物可供其他肠道物种如B. vulgatus利用,反过来互惠地增加自身的适应性。
蓝灿辉 | 热心肠先生
Nature [IF:42.778]

The evolution of cooperation within the gut microbiota



2016-04-25, Article

Abstract & Authors:展开

Cooperative phenotypes are considered central to the functioning of microbial communities in many contexts, including communication via quorum sensing, biofilm formation, antibiotic resistance, and pathogenesis. The human intestine houses a dense and diverse microbial community critical to health, yet we know little about cooperation within this important ecosystem. Here we test experimentally for evolved cooperation within the Bacteroidales, the dominant Gram-negative bacteria of the human intestine. We show that during growth on certain dietary polysaccharides, the model member Bacteroides thetaiotaomicron exhibits only limited cooperation. Although this organism digests these polysaccharides extracellularly, mutants lacking this ability are outcompeted. In contrast, we discovered a dedicated cross-feeding enzyme system in the prominent gut symbiont Bacteroides ovatus, which digests polysaccharide at a cost to itself but at a benefit to another species. Using in vitro systems and gnotobiotic mouse colonization models, we find that extracellular digestion of inulin increases the fitness of B. ovatus owing to reciprocal benefits when it feeds other gut species such as Bacteroides vulgatus. This is a rare example of naturally-evolved cooperation between microbial species. Our study reveals both the complexity and importance of cooperative phenotypes within the mammalian intestinal microbiota.

First Authors:
Seth Rakoff-Nahoum

Correspondence Authors:
Seth Rakoff-Nahoum

All Authors:
Seth Rakoff-Nahoum,K R Foster,Laurie E Comstock