REQUIREMENTS FOR BACTERIAL COLONIZATION OF ANIMAL TISSUE

动物组织细菌定植的要求

• 批准号: 6732660
• 负责人: Karen L Visick
• 金额: $ 21.28万
• 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 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6732660
• 关键词: Vibrio; bacterial genetics; biological signal transduction; bioluminescence; growth /development; microorganism growth; molecular cloning; mutant; nucleic acid sequence; southern blotting; squid; symbiosis; transposon /insertion element

There is a fine line between symbiosis (mutualism) and pathogenesis. Most, if not all, animals are colonized by bacteria, many of which-the organism's "normal flora"-are tolerated or even encouraged. To establish a symbiotic relationship with an animal, a prokaryotic organism must be able to recognize and respond to a specific environment, establish communication with the host, colonize the host tissue, evade defense mechanisms, persist and multiply. Each of these steps is mirrored in pathogenic interactions, whether primary or opportunistic-and even normal flora have pathogenic potential in the event of excessive multiplication or introduction into areas they do not ordinarily inhabit. Despite the ubiquity of bacterium-animal symbioses, little is known about the genetic and molecular details of these interactions. In addition to increasing basic understanding of these important prokaryote-eukaryote alliances, the study of symbiotic interactions is expected to improve understanding of how pathogenic organisms adopt, subvert, or bypass the mechanisms leading to symbiosis and why they provoke dissimilar responses from the eukaryotic cell. The symbiosis between the bioluminescent marine bacterium Vibrio fischeri and its host, the squid Euprymna scolopes, provides an excellent opportunity to study the biology of a bacterium which can form a long- term, mutualistic association with an animal host. The symbiosis has been well-characterized at the organismal level. We now propose to begin the detailed molecular characterization of the interactions between these organisms, including establishment of the symbiotic state, signalling between the two organisms and developmental changes occurring in both partners as the symbiosis progresses. The proposed research will investigate the requirements for V fischeri colonization of host tissue, using a straightforward screen for transposon-insertion mutants defective in the initial symbiotic events. Identification and characterization of the critical colonization genes will lay the foundation for understanding signal exchange between a prokaryote and a eukaryote during the establishment of a long-term association.

共生（互惠）和发病机制之间只有一线之隔。大多数（如果不是全部的话）动物都被细菌寄生，其中许多细菌——生物体的“正常菌群”——是可以容忍的，甚至是被鼓励的。为了与动物建立共生关系，原核生物必须能够识别和响应特定的环境，与宿主建立通信，定殖宿主组织，逃避防御机制，持续生存和繁殖。这些步骤中的每一步都反映在致病的相互作用中，无论是原生的还是机会性的——即使是正常的菌群，在过度繁殖或被引入它们通常不栖息的地区时，也有致病的潜力。尽管细菌-动物共生无处不在，但对这些相互作用的遗传和分子细节知之甚少。除了增加对这些重要的原核-真核生物联盟的基本了解外，共生相互作用的研究有望提高对病原生物如何采用、破坏或绕过导致共生的机制以及为什么它们会引起真核细胞不同反应的理解。生物发光的海洋细菌费氏弧菌（Vibrio fischeri）与其宿主乌贼（Euprymna scolopes）之间的共生关系，为研究一种可以与动物宿主形成长期互惠关系的细菌的生物学提供了极好的机会。这种共生关系在有机体水平上已经有了很好的特征。我们现在提议开始这些生物之间相互作用的详细分子表征，包括共生状态的建立，两种生物之间的信号传递以及在共生过程中双方发生的发育变化。拟议的研究将通过直接筛选在初始共生事件中存在缺陷的转座子插入突变体，来研究费氏弧菌在宿主组织中定植的要求。鉴定和鉴定关键的定殖基因将为理解原核生物和真核生物之间的信号交换奠定基础，并建立长期的联系。