Host and symbiont determinants of colonization by a co-evolved gut community

共同进化的肠道群落定植的宿主和共生体决定因素 项目摘要 宿主特有的肠道细菌是动物生物学和健康的核心，但澄清 管理肠道群落的正常和非典型组装的过程是具有挑战性的。最有胆量的 社区，特别是人类的社区，令人望而生畏地复杂；而其他社区，如 果蝇的细菌具有不同的成分，主要由来自 其他环境。在蜜蜂中，后肠的回肠区域包含一个 密集但简单的群落，仅由三种专门的细菌物种主导，这三种细菌包括 -gt；95%的细菌，尽管食品中存在的各种环境微生物不断进入。 这三个物种只在蜜蜂的肠道中发现，而不同但相关的菌株在相关的 蜜蜂物种。我们的试点工作建立了无菌培养条件、官方命名和 所有蜜蜂肠道成员的参考菌株，基于转座子的诱变方法， 用特定菌株或突变体控制定殖的规程和定量方法 对群落组成的描述。此外，宿主还可以接受基因研究： 已测序的基因组和相关资源可用于蜜蜂和RNAi方法 已经建立起来了。在这些基础上，我们将使用蜜蜂回肠作为模型 肠道群落，以确定构成基础的特定细菌和宿主因素 寄主物种特有的持久肠道群落的。我们将使用表达式分析 以及基于高通量测序的全基因组突变和突变筛选 确定影响蜜蜂回肠定植的共生菌基因并阐明寄主的作用 关于殖民的基因和途径。我们将研究焦点先驱共生体如何影响 肠道群落的组装和随后的组成。这将通过监测来实现 在实验肠道群落中的演替和通过识别影响 其他细菌物种和菌株的定植，包括通常存在的两种共生体 以及通常被排除在外的机会性或致病性细菌。这些 结果将揭示基于宿主和共生体的过程，这些过程支配着正常的、宿主- 特定的肠道微生物区系，并将阐明肠道群落有时是如何以及为什么发展的 不正常，损害宿主健康。 好了！

Host and symbiont determinants of colonization by a co-evolved gut community Project Summary Host-specific gut bacteria are central to the biology and health of animals, but elucidating the processes that govern normal and atypical assembly of gut communities is challenging. Most gut communities, and specifically those of humans, are dauntingly complex; whereas others, such as that of Drosophila, have variable compositions dominated by opportunistic bacterial species from other environments. In the honey bee (Apis mellifera), the ileum region of the hindgut contains a dense but simple community dominated by only three specialized bacterial species that comprise >95% of bacteria despite the continual entry of diverse environmental microbes present in food. These three species are found only in bee guts, and distinct but related strains are found in related bee species. Our pilot work established axenic culture conditions, official nomenclature, and reference strains for all bee gut community members, transposon-based mutagenesis methods, protocols for controlling colonization with specific isolates or mutants, and methods for quantitative description of community composition. Furthermore, the host is amenable to genetic studies: sequenced genome and associated resources are available for the honey bee, and RNAi methods have been established. Building on these foundations, we will use the honey bee ileum as a model gut community to determine the specific bacterial and host factors that underlie the establishment of a persistent gut community characteristic of a host species. We will use expression analyses and genome-wide mutagenesis and mutant screening based on high-throughput sequencing to identify symbiont genes affecting colonization of the bee ileum and to elucidate the effects of host genes and pathways on colonization. We will examine how a focal pioneer symbiont influences the assembly and subsequent composition of the gut community. This will be achieved by monitoring succession in experimental gut communities and by identifying symbiont genes that affect colonization by other bacterial species and strains, including both the symbionts normally present in the community and the opportunistic or pathogenic bacteria that are typically excluded. These results will reveal host and symbiont-based processes that govern development of a normal, host- specific gut microbiota and will illuminate how and why gut communities sometimes develop abnormally, to the detriment of host health. !