Molecular determinants of host-feeding manipulation and microbial colonization

项目摘要 所有的动物都生活在微生物包围的环境中，然而细菌对神经系统的影响 相对而言，系统研究较少。最近的数据表明，肠道细菌可能能够 调节宿主行为肠道细菌从宿主消耗的营养物质中获益， 细菌必须主要通过饮食传播，操纵宿主进食行为是一种主要模式， 哪些常驻微生物可以影响肠道微生物群落。由于这样的动态性质， 然而，在大多数系统中，研究喂食操纵要么具有挑战性，要么是不可能的。 首先，我们必须确定宿主和微生物都适合遗传操纵的系统， 其能够响应于限定的和自然的条件进行高通量行为筛选。这里我们 我建议在任何实验系统中首次全面研究这一现象，使用 蛔虫角线虫-与其天然相关的细菌-以获得机制的见解 转化为驱动宿主-微生物相互作用和决策的生物体间信号。C.线虫是一种细菌 经常在腐烂的植物材料中发现的食线虫，通常被微生物定殖。C. 在多细胞生物中，线虫拥有最广泛的分子、神经生物学和遗传学工具 真核生物，再加上这些蠕虫中的gnotobiotic文化，代表了一个非常有吸引力的 研究微生物对宿主行为影响的系统。 我最近证明了在C。肠道细菌可以影响化学感觉决定-一个代理 在某些情况下的进食行为-导致对这些气味产生的偏好增加 肠道微生物在平行的初步工作中，我发现嗅觉可塑性在肠道定植后， 在自然环境中，不同的微生物与肠道定植模式相关。总之，这些发现 表明C.线虫天然肠道微生物群可能能够通过以下方式影响微生物群组装： 影响进食行为。在这个建议中，我们的目标是建立C。作为一个系统来研究进食 通过开发工具来识别影响微生物组结构的行为参数， 自然主义的设置。我们建议通过实验将摄食与运动行为分离开来， 开发新型微流体成像装置。我们将在2-和3- 模拟蠕虫自然环境的微生物群落。然后我们将 利用自然微生物识别嗅觉行为中微生物依赖性变化的分子基础 社区.总之，我们建议开发一个新的领域的喂养操纵肠道微生物，与C。 以优雅为中心的杰出典范。我们预计，我们在本提案中确定的原则应 推广到多个系统，我们发现的神经活性化合物有可能影响 不同宿主的神经系统功能

Project Summary All animals live in environments surrounded by microbes, yet the impact of bacteria on nervous systems has been relatively under-studied. Recent data suggests that commensal gut bacteria may be capable of modulating host behavior. Gut bacteria benefit from nutrients consumed by their host and because these bacteria must be transmitted largely via diet, manipulation of host feeding behavior is a principal mode by which resident microbes can influence the gut microbial community. Due to the dynamic nature of such an interaction, studying feeding manipulation has been either challenging or impossible to date in most systems. First, we must identify systems in which both host and microbe are amenable to genetic manipulation, and which enable high-throughput behavioral screening in response to defined and naturalistic conditions. Here, we propose to comprehensively study this phenomenon for the first time in any experimental system, using the roundworm C. elegans — in combination with its natural associated bacteria — to gain mechanistic insights into inter-organismal signals driving host-microbe interactions and decision making. C. elegans is a bacterial- feeding nematode that is often found in rotting plant material and is commonly colonized by microbes. C. elegans has some of the most extensive molecular, neurobiological and genetic tools of any multicellular eukaryote, and, coupled with the ease of gnotobiotic culture in these worms, represents a highly attractive system in which to study microbial influence on host behavior. I have recently shown that in C. elegans, gut bacteria can influence chemosensory decisions — a proxy for feeding behavior in certain contexts — resulting in increased preference for odors produced by these enteric microbes. In parallel preliminary work, I have found that olfactory plasticity upon gut colonization by diverse microbes correlates with gut colonization patterns in naturalistic settings. Together, these findings suggest that the C. elegans native gut microbiota may be capable of impacting microbiome assembly by influencing feeding behavior. In this proposal, we aim to establish C. elegans as a system to study feeding manipulation by developing tools to identify the behavioral parameters which influence microbiome structure in naturalistic settings. We propose to experimentally isolate ingestion from locomotory behavior through the development of novel microfluidics imaging devices. We will develop new behavioral assays in 2- and 3- dimensional arenas to present microbial communities mimicking the worms’ natural environment. We will then identify the molecular basis of microbial-dependent changes in olfactory behaviors using naturalistic microbial communities. Together, we propose to develop a new field of feeding manipulation by gut microbes, with C. elegans centered as a preeminent model. We anticipate that the principles we identify in this proposal should generalize to multiple systems and the neuroactive compounds we identify have the potential to impact nervous system function in diverse hosts.