Investigation of microbial factors required for integrated functions of the Droso

描述（由申请人提供）：动物肠道的正常功能取决于与常驻共生微生物的代谢和调节相互作用。这种微生物群落，也称为肠道微生物群，促进其宿主对营养物质的加工和同化，并影响宿主免疫系统的发育和功能。为了充分了解人类的营养和健康，我们必须确定主机相关的微生物群落的组装，动态和功能的基础原则。本项目的中心目标是在无菌果蝇中构建一个确定的肠道微生物群，然后利用该模型系统研究肠道微生物群落组装和功能的机制基础。第一个目的是确定微生物群物种组成对肠道群落组装的影响。将果蝇的四种优势肠道细菌物种单独和成对地重新引入无菌苍蝇（重新关联），并确定每个物种的定殖水平和定位。该分析将确定影响肠道微生物群结构的微生物之间的相互作用，并将生成具有确定的肠道微生物群落的蝇线。第二个目标将测试定义的微生物群是否可以恢复无菌苍蝇的正常功能，与传统饲养的苍蝇相比，无菌苍蝇显示出可靠的营养成分改变和发育延迟。将通过Aim 1产生的重新关联的蝇系与无菌和常规饲养的对照进行这些表型的比较，并对免疫和代谢功能的指标进行分析。为了阐明共生的机制基础，最终的目标将确定特定的基因和代谢途径所需的持久性的一个突出的细菌物种在果蝇肠道使用转座子诱变和体内选择重新关联的苍蝇。这些研究的结果将为果蝇微生物群成员如何组装和相互作用产生一个全面而详细的模型。未来的研究将测试这种模型，以进一步研究宿主和微生物群如何整合，在肠道中形成功能性伙伴关系。该项目的完成将对肠道微生物群落如何组装和发挥作用产生根本性的见解，与人类营养和一系列疾病，包括肥胖，腹泻相关性腹泻和炎症性肠病有关。 公共卫生相关性：该项目的目的是通过将该群落中的单个物种重新引入无菌苍蝇中，深入表征黑腹果蝇消化道中的共生细菌群落。研究结果将深入了解动物如何将消化道功能与其常驻微生物群落整合在一起，并与人类营养以及肥胖、抗生素相关腹泻和炎症性肠道疾病等疾病相关。

DESCRIPTION (provided by applicant): Normal function of the animal gut depends on metabolic and regulatory interactions with resident, symbiotic microorganisms. This community of microbes, also called the gut microbiota, facilitates processing and assimilation of nutrients by its host, and impacts the development and function of the host immune system. To fully understand human nutrition and health we must ascertain the principals that underlie assembly, dynamics and function of host-associated microbial communities. The central goal of this project is to construct a defined gut microbiota in germ-free Drosophila, and then to utilize this model system to investigate the mechanistic basis of gut microbial community assembly and function. The first aim is to determine the effect of microbiota species composition on gut community assembly. The four dominant gut bacterial species of Drosophila will be reintroduced into germ-free flies (re-associated) singly and in pairs, and the colonization level and localization of each species determined. This analysis will identify interactions between microbes that impact gut microbiota structure, and will generate fly lines with defined gut microbial communities. The second aim will test if defined microbiota can restore normal functions to germ-free flies, which show a reliably altered nutrient profile and delayed development compared to conventionally-reared flies. Re-associated fly lines generated through Aim 1 will be compared to germ-free and conventionally reared controls for these phenotypes, and profiled for indicators of immune and metabolic function. To elucidate the mechanistic basis of symbiosis, the final aim will identify specific genes and metabolic pathways required for the persistence of a prominent bacterial species in the Drosophila gut using transposon mutagenesis and in vivo selection in re-associated flies. The results of these studies will generate a comprehensive and detailed model for how members of the Drosophila microbiota assemble and interact. Future research will test this model to further investigate how host and microbiota integrate to form a functional partnership in the gut. The completion of this project will yield fundamental insights into how gut microbial communities assemble and function, with relevance to human nutrition and a range of diseases including obesity, antibiotic-associated diarrhea, and inflammatory bowel disease. PUBLIC HEALTH RELEVANCE: The project aims to characterize in depth the symbiotic, bacterial community that resides in the digestive tract of Drosophila melanogaster by reintroducing individual species from this community into germ-free flies. The results will provide insight into how animals integrate functions of the digestive tract with its resident microbial community, and will be relevant to human nutrition, and diseases including obesity, antibiotic-associated diarrhea, and inflammatory bowel disease.