Vibrio fischeri as a model of bacterial colonization

描述（由申请人提供）：项目摘要：最近的研究表明，有益和致病微生物协会通常使用相同的宿主和细菌表面分子和生物活性化合物来介导它们在上皮细胞表面的相互作用。这些发现提出了一个问题：宿主如何通过同时阻止病原体和鼓励有益的微生物伴侣来促进健康？鱿鱼Euprymna spectopes的上皮组织与其革兰氏阴性细菌伙伴费氏弧菌（Vibrio fischeri）之间的共生关系正被用作解决这一关键问题的实验系统。在这种关联中，细菌伴侣的脂多糖和肽聚糖的衍生物与上皮细胞相互作用，以在共生关系的建立期间指导宿主发育。拟议的研究旨在确定这种通信的分子基础。主要目标是： 1.为了表征细菌产物的宿主模式识别受体在共生开始期间何时何地表达-将使用定位动物组织中特定mRNA和蛋白质的敏感技术来询问：宿主受体的表达如何介导或限制合作伙伴的相互作用以促进有益的关联？ 2.为了确定在V. fischeri的能力产生生物活性配体的缺陷对共生的影响-使用为V. fischeri开发的细菌遗传技术，将创建产量不足和过量的突变体，以询问：细菌配体合成的正常水平如何促进有益的相互作用？ 3.为了确定宿主反应细菌配体使用主机基因组分析-微阵列研究的基因表达的宿主组织在早期发展将地址：什么基因表达模式的主机与有益的合作伙伴的相互作用的基础？ 相关性：宿主-受体/细菌-配体相互作用在整个动物进化过程中一直是保守的。二进制鱿鱼弧菌共生提供了一个相对简单的模型，其中确定和定义基本的，共享的机制，基本细菌定殖人类和其他动物上皮细胞。它提供了一个强有力的补充，类似的，但更复杂的，无菌脊椎动物模型的有益协会。

DESCRIPTION (provided by applicant): Project Summary: Recent studies have demonstrated that beneficial and pathogenic microbial associations often use the same host and bacterial surface molecules and bioactive compounds to mediate their interactions at epithelial cell surfaces. These findings beg the question: how does the host promote health by simultaneously discouraging pathogens and encouraging beneficial microbial partners? The symbiosis between the epithelial tissues of the squid Euprymna scolopes and its Gram- negative bacterial partner Vibrio fischeri is being exploited as an experimental system by which to address this critical question. In this association, derivatives of lipopolysaccharide and peptidoglycan of the bacterial partner interact with epithelial cells to direct host development during the establishment of the symbiosis. The proposed research seeks to define the molecular underpinnings of this communication. The principal aims are: 1. To characterize when and where host pattern-recognition receptors for bacterial products are expressed during the onset of the symbiosis - Sensitive techniques to localize specific mRNAs and proteins in animal tissues will be used to ask: How does the expression of host receptors mediate or restrict the interaction of the partners to promote a beneficial association? 2. To determine the influence on symbiosis of defects in V. fischeri's capacity to produce bioactive ligands - Using bacterial genetic techniques developed for V. fischeri, under- and overproducing mutants will be created to ask: How does a normal level of bacterial ligand synthesis promote beneficial interactions? 3. To identify host responses to bacterial ligands using host genomic analyses - Microarray studies of genes of the host tissues expressed in early development will address: What gene-expression patterns of the host underlie the interactions with a beneficial partner? Relevance: Host-receptor/bacterial-ligand interactions have been conserved throughout animal evolution. The binary squid-vibrio symbiosis offers a relatively simple model in which to identify and define the basic, shared mechanisms by which essential bacteria colonize human and other animal epithelia. It provides a powerful complement to the similar, yet more complex, germ-free vertebrate models of beneficial associations.