美国华盛顿大学Joseph D. Mougous和Elhanan Borenstein等研究人员的一项最新合作研究，发现了人类肠道细菌含有获得性细菌间防御系统。相关论文于10月30日在线发表于《自然》杂志。

研究人员报道了在人类肠道微生物组内的拟杆菌属物种中获得性细菌防御（AID）基因簇的出现。这些簇编码免疫基因的阵列，这些基因可防御VI型分泌系统（T6SS）介导的种内和种间细菌拮抗作用。此外，这些簇位于移动元件上，研究人员证明了它们的转移足以在体外和致癌小鼠中产生毒素抗性。最后，研究人员确定并验证了在拟杆菌属基因组中广泛存在的重组酶相关AID亚型（rAID-1）的保护能力。这些rAID-1基因簇具有活跃基因获取的结构，并包括源自多种生物的毒素的潜在免疫因子。这些数据表明，通过AID系统中和接触依赖性细菌拮抗作用有助于塑造人体肠道微生物组生态。

据介绍，人类的胃肠道由密集而多样的微生物群落组成，其组成与健康息息相关。饮食和宿主免疫力等外在因素不足以解释该群落的组成，并且共存微生物之间的直接相互作用已被认为是微生物组组成的重要驱动因素。来自肠道微生物组的细菌基因组包含几种介导接触依赖性细菌拮抗作用的途径。革兰氏阴性细菌的许多成员编码VI型分泌系统（T6SS），这有助于将毒性效应蛋白递送到相邻细胞中。

附：英文原文

Title: Human gut bacteria contain acquired interbacterial defence systems

Author: Benjamin D. Ross, Adrian J. Verster, Matthew C. Radey, Danica T. Schmidtke, Christopher E. Pope, Lucas R. Hoffman, Adeline M. Hajjar, S. Brook Peterson, Elhanan Borenstein, Joseph D. Mougous

Issue&Volume: 2019-10-30

Abstract: The human gastrointestinal tract consists of a dense and diverse microbial community, the composition of which is intimately linked to health. Extrinsic factors such as diet and host immunity are insufficient to explain the constituents of this community, and direct interactions between co-resident microorganisms have been implicated as important drivers of microbiome composition. The genomes of bacteria derived from the gut microbiome contain several pathways that mediate contact-dependent interbacterial antagonism13. Many members of the Gram-negative order Bacteroidales encode the type VI secretion system (T6SS), which facilitates the delivery of toxic effector proteins into adjacent cells4,5. Here we report the occurrence of acquired interbacterial defence (AID) gene clusters in Bacteroidales species that reside within the human gut microbiome. These clusters encode arrays of immunity genes that protect against T6SS-mediated intra- and inter-species bacterial antagonism. Moreover, the clusters reside on mobile elements, and we show that their transfer is sufficient to confer resistance to toxins in vitro and in gnotobiotic mice. Finally, we identify and validate the protective capability of a recombinase-associated AID subtype (rAID-1) that is present broadly in Bacteroidales genomes. These rAID-1 gene clusters have a structure suggestive of active gene acquisition and include predicted immunity factors of toxins derived from diverse organisms. Our data suggest that neutralization of contact-dependent interbacterial antagonism by AID systems helps to shape human gut microbiome ecology. An interbacterial defence strategy, involving clusters of immunity genes against toxins released by the type VI secretion system of the same or different species, is widespread among Bacteroides species, and transfer of these gene clusters confers resistance to toxins in vitro and in the mammalian gut.

DOI: 10.1038/s41586-019-1708-z

Source:https://www.nature.com/articles/s41586-019-1708-z