Vibrio Virulence Determinants in a Benign Colonization

描述(申请人提供)：拟议研究的长期目标是了解人类与其微生物区系之间发生的复杂对话，以及随着宿主的成熟，这种分子对话如何支持它们的动态稳定性。为了实现这一目标，需要清楚地了解这些基本微生物群落是如何形成的，它们是如何发挥作用的，以及它们在日常生活中的自然生物节奏中扮演着什么角色。为了帮助发现人体内和体内数百或数千种微生物物种之间复杂相互作用的规则，科学家们使用简单的模型系统来提供一个窗口，了解不同细菌与宿主之间发挥作用的基本原理。一种这样的模式系统是生物发光细菌费氏弧菌与其鱿鱼宿主Euprymna scolope之间的发光器官共生。这种联系的一个基本特征是细菌和它们所关联的上皮组织之间的关系具有深刻的日常节律。由于这种组织很容易成像，并被单一的、基因可操纵的细菌物种定居，因此共生提供了难得的机会，以高时间和空间分辨率破译相互的分子和生化对话，这对自然共生的持续至关重要。拟议研究的具体目标是：(I)描述允许伴侣启动节律相互作用的步骤，(Ii)确定代谢循环的发展是如何支撑这种节律的，以及(Iii)确定驱动进化保守的共生节律的分子机制(即“时钟”)。这些目标将通过多种方法的结合来实现，包括宿主组织重塑的成像和分析，构建用于探测定植事件的细菌突变体，以及在共生开始时跟踪和探测共生，以及随着其节律模式从不成熟发展到成熟状态。

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.