REQUIREMENTS FOR BACTERIAL COLONIZATION OF ANIMAL TISSUE

动物组织细菌定植的要求

• 批准号: 7094591
• 负责人: Karen L Visick
• 金额: $ 28.4万
• 依托单位: LOYOLA UNIVERSITY CHICAGO
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7094591
• 关键词: Vibrio; bacterial genetics; biological signal transduction; bioluminescence; growth /development; host organism interaction; microorganism growth; molecular cloning; mutant; nucleic acid sequence; southern blotting; squid; symbiosis; transposon /insertion element

DESCRIPTION (provided by applicant): The long-term objective of our research is to define signals that allow bacteria to communicate with a host and to identify the pathways by which they respond to the host environment. The symbiotic association between the Hawaiian squid, Euprymna scolopes, and its bacterial partner, Vibrio fischeri, provides a simple, elegant model system for studying bacteria-animal interactions. Only V. fischeri colonizes the squid. The evidence to date suggests that V. fischeri actively participates in achieving the observed specificity of the association. The factors that dictate this specificity, however, are not yet understood. We have identified a cluster of genes (syp, symbiosis polysaccharide locus) that is required for V. fischeri to initiate symbiosis, and an unlinked sensor kinase regulator, rscS, that controls syp transcription. Four additional regulators are proposed or known to also control syp transcription, including a ?54-dependent response regulator, SypG, and 2 additional 2-component regulators. Thus, syp is controlled by at least 3 proteins that are predicted to sense and respond to the environment. Multi-copy expression of a particular allele (rscS*) causes V. fischeri to express syp-dependent novel phenotypes consistent with altered cell-cell interactions: wrinkled colonies on solid complex media and pellicle formation in liquid minimal medium. We propose to elucidate the major regulatory mechanisms controlling syp transcription and identify additional genes associated with syp-dependent phenotypes. We will identify the polysaccharide produced by the syp locus and identify any differences in cell surface properties. Finally, we will examine in more detail the nature of the symbiosis defect of syp mutants and explore possible explanations to account for it. The experiments proposed here will expand our understanding of how colonization is initiated and how signal exchange occurs between a prokaryote and a eukaryote during the establishment of a long-term association. The relevance to public health lies in the potential of this model system to reveal novel mechanisms by which bacteria interact with an animal host. Such information could potentially allow the design of new antimicrobial agents. Our research organism is closely related to bacteria that cause gastroenteritis in humans, including the emerging pathogens, V. parahaemolyticus and V. vulnificus. Studying this model may also lead to approaches that prevent, reduce or treat such infections.

描述（由申请人提供）：我们研究的长期目标是定义允许细菌与宿主通信的信号，并确定它们对宿主环境做出反应的途径。夏威夷鱿鱼（Euprymna scolopes）与其细菌伙伴费氏弧菌（Vibrio fischeri）之间的共生关系为研究细菌与动物之间的相互作用提供了一个简单而优雅的模型系统。只有费氏弧菌 (V. fischeri) 寄居在乌贼中。迄今为止的证据表明，V. fischeri 积极参与实现所观察到的关联特异性。然而，决定这种特殊性的因素尚不清楚。我们已经确定了费氏弧菌启动共生所需的一组基因（syp，共生多糖基因座），以及控制 syp 转录的未连接的传感器激酶调节因子 rscS。提出或已知四个额外的调节器也控制 syp 转录，包括 ?54 依赖性反应调节器 SypG 和 2 个额外的 2 组分调节器。因此，syp 受至少 3 种蛋白质控制，预计这些蛋白质能够感知环境并对环境做出反应。特定等位基因 (rscS*) 的多拷贝表达导致 V. fischeri 表达与细胞间相互作用改变一致的 syp 依赖性新表型：固体复合培养基上的皱纹集落和液体基本培养基中的薄膜形成。我们建议阐明控制 syp 转录的主要调控机制，并鉴定与 syp 依赖性表型相关的其他基因。我们将鉴定 syp 位点产生的多糖，并鉴定细胞表面特性的任何差异。最后，我们将更详细地研究 syp 突变体共生缺陷的本质，并探索可能的解释。这里提出的实验将扩大我们对定植如何启动以及在建立长期关联过程中原核生物和真核生物之间如何发生信号交换的理解。与公共卫生的相关性在于该模型系统有可能揭示细菌与动物宿主相互作用的新机制。这些信息可能有助于设计新的抗菌药物。我们的研究微生物与引起人类胃肠炎的细菌密切相关，包括新出现的病原体副溶血弧菌和创伤弧菌。研究该模型还可能导致找到预防、减少或治疗此类感染的方法。