Marine Biotech Fellowship: Molecular Analysis of Bacterial Genes Involved in Establishing the Vibrio Fischeri/Euprymna Scolopes Symbiotic Relationship

9212452吉尔森这个项目的长期目标是了解建立细菌/动物共生的机制。费氏弧菌既是一种自由生活的海洋细菌，也是海泡鱼、鱿鱼和单中心鱼发光器官的生物发光居民。费斯切里乌贼和小乌贼Euprymna scolope的结合提供了一种互惠互利的模式关系，并已被证明服从于实验室和分子遗传学方法。该项目旨在识别表达为费氏弧菌的基因和基因产物，并对宿主内的条件做出反应。只有当细菌与鱿鱼相关时才表达的基因，将通过与一种基因的融合来识别，该基因的表达对细菌在宿主内的生存至关重要，但在选择性条件下，在宿主外是致命的。蛋白质凝胶(2-D)将被用来识别在这两种不同环境中优先合成的蛋白质。由于生物发光在共生条件下优先表现，并受密度依赖的信息素样分子控制，因此也是该调节子一部分的其他基因将通过泥胶融合技术进行鉴定。费氏弧菌与棘球藻之间的关系显然是一种互惠互利的关系，但这种关系的建立和维持在进化上与共生、寄生和致病关联有关。细胞间通讯、信号转导和基因激活机制的遗传基础信息将适用于所有这些系统。***

9212452 GILSON The long term objective of this project is to understand the mechanisms involved in establishing a bacterial/animal symbiosis. Vibrio fischeri exists both as a free-living marine bacteria and as a bioluminescent inhabitant of the light organ of sepiolid squid and monocentrid fish. The association of V. fischeri and the small squid, Euprymna scolopes, offers a model mutualistic relationship and has already proven to be amenable to laboratory and molecular genetic methodologies. This project is directed at identifying the genes and gene products that are expressed as V. fischeri senses and responds to the conditions within the host. Genes that are expressed only when the bacteria is in association with the squid will be identified by fusions with a gene whose expression is essential for bacterial survival within the host, but, under selective conditions, is lethal outside the host. Protein gels (2-D) will be used to identify proteins that are preferentially synthesized in these two different environments. And since bioluminescence is preferentially exhibited under symbiotic conditions and is controlled by a density-dependent, pheromone-like molecule, other genes that are also part of this regulon will be identified through mudlac fusion technology. The relationship between V. fischeri and E. scolopes is apparently a mutualistic one, however its establishment and maintenance is evolutionarily related to commensal, parasitic and pathogenic associations. Information of the genetic basis for mechanisms of cell-cell communications, signal transduction and gene activation will be applicable to all of these systems. ***