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依赖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区系，促进宿主对营养物质的处理和吸收，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，我们必须确定与宿主相关的微生物群落的组装、动态和功能的基本原理。本项目的中心目标是在无菌果蝇体内构建一个明确的肠道微生物区系，然后利用该模型系统来研究肠道微生物群落组装和功能的机制基础。第一个目标是确定微生物区系物种组成对肠道群落组装的影响。果蝇的四种主要肠道细菌将被单独和成对地重新引入无菌果蝇中，并确定每个物种的定植水平和定位。这项分析将确定影响肠道微生物区系结构的微生物之间的相互作用，并将产生具有定义的肠道微生物群落的苍蝇线。第二个目标是测试定义的微生物区系是否能恢复无菌果蝇的正常功能，与传统饲养的果蝇相比，无菌果蝇的营养状况发生了可靠的变化，发育延迟。通过AIM 1产生的重新关联的苍蝇品系将与这些表型的无细菌和传统饲养的对照进行比较，并分析免疫和代谢功能的指标。为了阐明共生的机制基础，最终目的是利用转座子突变和在重新关联的果蝇中进行体内选择，确定果蝇肠道中一个主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组装和相互作用产生一个全面和详细的模型。未来的研究将测试这一模型，以进一步研究宿主和微生物区系是如何整合在肠道中形成功能伙伴关系的。该项目的完成将产生对肠道微生物群落如何组装和功能的基本见解，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。 与公共卫生相关：该项目旨在通过将该群落中的个别物种重新引入无菌果蝇来深入表征驻留在黑腹果蝇消化道的共生细菌群落。这些结果将为动物如何将消化道的功能与其驻留的微生物群落整合在一起提供洞察，并将与人类营养以及肥胖、抗生素相关性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.