Vibrio Virulence Determinants in a Benign Colonization

描述（由申请人提供）：拟议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在宿主成熟时支持其动态稳定性。要实现这一目标，需要清楚地了解这些基本微生物群落是如何形成的，它们是如何运作的，以及它们在日常生活的自然生物节律中扮演什么角色。为了帮助发现存在于人体内外的数百或数千种微生物之间复杂相互作用的规则，科学家们使用简单的模型系统为了解不同细菌与宿主相互作用的基本原理提供了一个窗口。一个这样的模式系统是生物发光的细菌，费氏弧菌和它的宿主鱿鱼之间的光器官共生。这种关联的一个基本特征是细菌和与其相关的上皮组织之间的关系具有深刻的日常节律。因为这种组织很容易成像，并且是由单一的、遗传上可操纵的细菌物种定植的，所以共生关系提供了难得的机会，以高时间和空间分辨率破译相互的分子和生化对话，这对自然共生关系的持久性至关重要。拟议研究的具体目标是：(i)描述允许伴侣启动其节律相互作用的步骤，（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，包括对宿主组织重塑的成像和分析，构建细菌突变体以探测定植事件，以及跟踪和探测共生关系的启动，以及其节律模式从未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.