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。这个微生物群落，也被称为肠道微生物群，促进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。为了充分了解人类营养和健康，我们必须确定宿主相关微生物群落的组装、动态和功能的基本原理。本项目的中心目标是在无菌果蝇中构建一个明确的肠道微生物群，并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单独或成对重新引入无菌蝇（重新结合），并确定每种细菌的定植水平和定位。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，并将产生具有确定肠道微生物群落的蝇系。第二个目标是测试确定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状况改变和发育延迟。通过Aim 1产生的重关联蝇系将与无菌和常规饲养的这些表型对照进行比较，并对免疫和代谢功能指标进行分析。为了阐明共生的机制基础，最终目的是利用转座子诱变和重关联果蝇的体内选择，确定果蝇肠道中一个重要细菌物种持续存在所需的特定基因和代谢途径。这些研究的结果将为果蝇微生物群的成员如何聚集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一模型，以进一步研究宿主和微生物群如何在肠道中整合形成功能伙伴关系。该项目的完成将对肠道微生物群落如何聚集和功能产生根本性的见解，与人类营养和一系列疾病相关，包括肥胖、抗生素相关性腹泻和炎症性肠病。

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.