Vibrio Virulence Determinants in a Benign Colonization

该研究的长期目标是了解人类与其微生物群之间发生的复杂对话，以及这种分子对话如何随着宿主成熟而支持其动态稳定性。为了实现这一目标，需要清楚地了解这些基本的微生物群落如何形成，它们如何发挥作用，以及它们在日常生活的自然生物节律中发挥什么作用。为了帮助发现存在于人体内和人体上的数百或数千种微生物之间复杂相互作用的基本规则，科学家们使用简单的模型系统来提供一个窗口，以了解不同细菌与宿主一起发挥作用的基本原理。一个这样的模型系统是发光细菌，费氏弧菌，和它的鱿鱼宿主，Euprymna spleopes之间的光器官共生。这种关联的一个基本特征是细菌与它们所关联的上皮组织之间的关系具有深刻的每日节律。由于这种组织很容易成像，并且被一种单一的、可遗传操纵的细菌物种所定殖，共生提供了难得的机会，以高的时间和空间分辨率来破译相互的分子和生物化学对话，这对自然共生的持续性至关重要。 拟议研究的具体目标是（i）表征允许伴侣启动其节律性相互作用的步骤，（ii）定义代谢循环的发展如何成为这种节律的基础，以及（iii）确定分子机制（即，“时钟”）驱动着进化上保守的共生节奏。这些目标将通过多种方法的组合来实现，包括成像和分析宿主组织重塑，构建细菌突变体以探测定植事件，以及在共生开始时跟踪和探测共生，以及随着其节奏模式从不成熟状态发展到成熟状态。

DESCRIPTION (provided by applicant): The long-term objectives of the proposed research are to understand the complex dialogue that occurs between humans and their microbiota, and how this molecular conversation supports their dynamic stability as the host matures. To achieve this goal requires a clear understanding of how these essential microbial communities form, how they function, and what role they play in the natural biological rhythms that characterize daily life. To help discover the rules underlying the complex interactions between the hundreds or thousands of microbial species present in and on the human body, scientists use simple model systems to provide a window into the fundamental principles by which different bacteria function with their host. One such model system is the light- organ symbiosis between the bioluminescent bacterium, Vibrio fischeri, and its squid host, Euprymna scolopes. A fundamental characteristic of this association is a profound daily rhythm in the relationship between the bacteria and the epithelial tissue with which they associate. Because this tissue is easily imaged, and is colonized by a single, genetically manipulable bacterial species, the symbiosis offers the rare opportunity to decipher, with high temporal and spatial resolution, the reciprocal molecular and biochemical dialogue that is essential for persistence of a natural symbiosis. The specific aims of the proposed research are to (i) characterize the steps that allow the partners to initiate their rhythmic interaction, (ii) define how the development of metabolic cycling underlies this rhythm, and (iii) determine the molecular mechanisms (i.e., 'clocks') that drive evolutionarily conserved symbiotic rhythms. These aims will be achieved by a combination of approaches including imaging and analysis of host-tissue remodeling, construction of bacterial mutants for probing colonization events, and tracking and probing the symbiosis as it is initiated, and as its rhythmic patterns develop from the immature into mature state.