Vibrio fischeri as a model of bacterial colonization

费氏弧菌作为细菌定植模型

基本信息

批准号：
6620358
负责人：
MARGARET J MC FALL-NGAI
金额：
$ 26.82万
依托单位：
UNIVERSITY OF HAWAII AT MANOA
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-12-01 至 2003-11-30
项目状态：
已结题

项目摘要

Many animal epithelial tissues are colonized by benign, often essential, bacterial symbionts, such as those in the oral cavity and along the apical surfaces of the cells lining the intestinal and respiratory tracts. These tissues, which occur at the interface between the environment and the body, are also the sites of infection by many bacterial pathogens (e.g., Haemophilus influenzae and Neisseria meningitidis). In both pathogenic and cooperative associations the bacteria and host cells communicate most commonly through interactions of their surface molecules or through the secretion of other bioactive compounds. The model symbiosis between the epithelial tissues of the squid Euprymna scolopes and its Gram-negative, luminous bacterial associate Vibrio fischeri is being exploited as a system by which to characterize these cross-Domain cell-cell interactions and to provide insight into the critical differences between beneficial and pathogenic animal-bacterial associations. Recent studies of this system have shown that lipopolysaccharide (LPS), the principal surface molecule of Gram-negative bacteria and the product responsible for the most dramatic mammalian responses to infective bacteria, induces specific changes in the squid host's cell biology and morphology during the initial stages of the relationship. In addition, characterization of host responses to LPS has revealed that this molecule works synergistically with proteinaceous compounds exported by the symbiont. The types of host cell 'behaviors' induced by these V. fischeri-derived factors include: the production of mucus to facilitate colonization of susceptible tissues, and the onset of a morphogenetic program that transforms host tissues from a morphology characteristic of the uncolonized juvenile to one characteristic of the mature, adult association. Several other identified responses of host cells to V. fischeri may also be affected by these compounds. The goal of this interdisciplinary project is to characterize bioactive molecules of V. fischeri, specifically LPS and the peptides that work in concert with LPS, that mediate host tissue responses during the early phases of the squid-vibrio association. The specific aims of this proposal are to: (1) characterize the structures of wild-type V. fischeri LPS and the LPS derived directly from the symbiosis, as well as characterize LPS derived from specific LPS-synthesis mutants that are associated with compromised host responses; (2) determine the precise biochemical identity and activity of bacterial molecules that act synergistically with LPS; and, (3) determine what aspects of LPS structure play a role in conferring resistance to host antimicrobial peptides.

许多动物上皮组织都被良性的、通常是必需的细菌共生体定植，例如口腔中以及沿着肠道和呼吸道内壁细胞顶端表面的共生体。这些组织位于环境和身体之间的界面，也是许多细菌病原体（例如流感嗜血杆菌和脑膜炎奈瑟菌）的感染部位。在致病关联和协同关联中，细菌和宿主细胞最常见地通过其表面分子的相互作用或通过其他生物活性化合物的分泌来进行交流。鱿鱼 Euprymna scolopes 的上皮组织与其革兰氏阴性发光细菌伙伴费氏弧菌 (Vibrio fischeri) 之间的共生模型被用作一个系统，通过该系统来表征这些跨域细胞间相互作用，并深入了解之间的关键差异有益和致病的动物-细菌关联。最近对该系统的研究表明，脂多糖（LPS）是革兰氏阴性细菌的主要表面分子，也是哺乳动物对感染性细菌做出最剧烈反应的产物，在初始阶段会引起鱿鱼宿主细胞生物学和形态学的特定变化。关系的阶段。此外，宿主对 LPS 反应的表征表明，该分子与共生体输出的蛋白质化合物具有协同作用。由这些费氏弧菌衍生因子诱导的宿主细胞“行为”类型包括：产生粘液以促进易感组织的定植，以及启动形态发生程序，将宿主组织从未定植幼体的形态特征转变为易感组织的形态发生程序。成熟、成人协会的特征之一。其他几种已确定的宿主细胞对费氏弧菌的反应也可能受到这些化合物的影响。这个跨学科项目的目标是表征费氏弧菌的生物活性分子，特别是脂多糖和与脂多糖协同作用的肽，它们在鱿鱼-弧菌关联的早期阶段介导宿主组织反应。该提案的具体目标是：（1）表征野生型费氏弧菌 LPS 和直接源自共生的 LPS 的结构，以及表征源自与受损宿主相关的特定 LPS 合成突变体的 LPS回应； (2) 确定与LPS协同作用的细菌分子的精确生化特性和活性； (3) 确定 LPS 结构的哪些方面在赋予宿主抗菌肽抗性方面发挥作用。