Ecology of the intestinal microbe, Faecalibacterium prausnitzii

肠道中的微生物群落(微生物区系)消化我们的食物，保护我们免受传染病的侵袭。微生物区系对这些过程的贡献只在少数几个具体情况下才为人所知，部分原因是微生物的巨大多样性(我们肠道中的1000多个物种)以及它们相互作用以及与我们相互作用的复杂性。在这项拟议的研究中，我将在一个简化的微生物区系(12个物种)的背景下探索其中一些相互作用，重点是一种关键微生物--普鲁斯尼茨杆菌。实验将在老鼠和社区培养系统中进行。*细菌种类，普鲁斯尼茨杆菌，是健康成年人结肠微生物区系中的主要成员。这是肠道中消化和吸收复杂食物的部分，普氏福氏杆菌被认为是这些过程的关键贡献者。普氏酵母菌消化膳食纤维作为能量来源，并产生一种重要的代谢物丁酸盐，对结肠健康有好处。此外，普氏疟原虫还能分泌多种分子，通过与肠道免疫系统的通讯机制减少肠道炎症，这些机制目前只有部分人知道。促进这些功能的必要条件尚不清楚。肠道炎症是对感染的正常反应，是对微生物区系的重大压力，可能导致群落组成的短暂或有时长期变化(即一些物种死亡，而另一些物种繁荣)和行为(即切换到生存模式)。在发炎的肠道中，普氏金黄色葡萄球菌的水平显著降低，这表明这种生物对肠道生态系统的变化很敏感。目前，人们对开发基于恢复该物种健康特性的治疗方法非常感兴趣，这些患者患有慢性炎症性疾病，如克罗恩病。要做到这一点，需要更好地了解普鲁斯尼茨菌以及微生物区系的其他成员如何调节它们与肠道环境、微生物区系其他成员和肠道免疫系统的相互作用，以恢复肠道过程。这一理解将有助于我们对健康肠道的整体理解。

Microbial communities (microbiota) in the gut digest our food and protect us against infectious organisms. How the microbiota contribute to these processes is known in only a few specific cases, partly due to the enormous diversity of microbes (more than 1000 species in our gut) and the complexity of their interactions with each other and with us. In this proposed research, I will explore some of these interactions in the context of a simplified microbiota (12 species), with a focus on a key microbe, Faecalibacterium prausnitzii. Experiments will be conducted in mice and in community culture systems. ******The bacterial species, F. prausnitzii, is a dominant member of the microbiota in the colon of healthy adults. This is the part of the gut where complex foods are digested and absorbed, and F. prausnitzii is thought to be a key contributor to these processes. F. prausnitzii digests dietary fiber as a source of energy and produces an important metabolite, butyrate, which has beneficial effects on colon health. In addition, F. prausnitzii has been shown to secrete a variety of molecules that reduce gut inflammation through mechanisms of communication with the intestinal immune system that are only partially known. The conditions necessary for promoting these functions are not known.******Intestinal inflammation, which is a normal response to infection, is a significant stress on the microbiota and can lead to transient or sometimes long-term changes in community composition (i.e. some species die while others flourish) and behavior (i.e. switch to survival mode). F. prausnitzii levels are dramatically reduced in the inflamed gut, suggesting that this organism is sensitive to changes in the gut ecosystem. There is currently great interest in developing therapies based on restoring the healthful qualities of this species for patients with chronic inflammatory diseases such as Crohn's disease. To do so will require a better understanding of how F. prausnitzii, as well as other members of the microbiota, regulate their interactions with the intestinal environment, other members of the microbiota and the intestinal immune system to restore gut processes. This understanding will contribute to our overall understanding of a healthy gut.**