Genetics and Photophysiology of Novel Anoxyphototrophs

新型无氧光养生物的遗传学和光生理学

• 批准号: 9303836
• 负责人: Carl Bauer
• 金额: $ 37.76万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9303836&HistoricalAwards=false
• 关键词: Genetics; Photophysiology; Novel; Anoxyphototrophs

9303836 Bauer The recently described nonsulfur purple photosynthetic bacterium Rhodospirillum centenum exhibits several physiological traits previously unknown among photosynthetic eubacteria. One feature is the existence of a life cycle involving the formation of heat and desiccation resistant cysts. Germination of Rsp. centenum cysts leads to cell differentiation characterized by swarm cell behavior on solid media. Swarm cells grown on solid agar medium have numerous lateral flagella and are distinct from non-swarm cells which bear a single polar flagellum. Swarm cell differentiation appears to be a stage of a life cycle and to be a specific response to an increase in medium viscosity. A second unusual feature of Rsp. centenum is that swarm cell colonies have the capacity to migrate rapidly either towards or away from light; rates as high as 45 mm/hour have been observed. An action spectrum has demonstrated that 585 nm light repels whereas light over the region 800-880 nm attracts. Major goals of this proposal include the physiological characterization of swarm cells as well as an analysis of phototactic behavior of Rsp. centenum. In addition, genetic analyses of swarm cell formation as well as phototaxis will be undertaken to determine the number and nature of the genetic loci involved in these processes. These studies will also be augmented by biochemical and molecular genetic characterization of the photoreceptor(s) involved. It is anticipated that the proposed research will provide significant information on prokaryotic cell differentiation and in addition, should provide the first molecular analysis of the mechanism of phototaxis in eubacteria. We also propose to extend genetic analysis of bacterial photosynthesis to evolutionarily divers species of eubacterial phototrophs. The aim of this area of research is to obtain clones of bacteriochlorophyll biosynthesis genes from Chlorobium tepidum, Heliobacterium gestii, Rhodopseudomonas viridis and cyanobacteria for the purpose of determining the extent to which a Photosynthesis Gene Cluster is conserved among various genera and species of phototrophic prokaryotes. The clones obtained will also be used to generate sequence analyses of genetic loci common to bacterial and plant chlorophyll biosynthetic pathways for use in subsequent studies of chlorophyll biosynthesis in plant systems. ***

9303836鲍尔，最近被描述的非硫紫色光合细菌，中央红螺菌显示了几个以前在光合作用真细菌中未知的生理特性。一个特征是存在一个生命周期，包括形成耐高温和耐干燥的包囊。RSP的萌发。百里香胞囊导致细胞分化，其特征是细胞在固体培养基上的聚集行为。在固体琼脂上生长的群体细胞有大量的侧鞭毛，与非群体细胞不同，非群体细胞只有一根极生鞭毛。群体细胞分化似乎是生命周期的一个阶段，是对介质粘度增加的一种特殊反应。RSP的第二个不同寻常的特征。百分之一是群体细胞菌落有能力快速地向光或远离光迁移；观察到高达45毫米/小时的速率。作用光谱表明，585 nm的光相互排斥，而800-880 nm区域的光相互吸引。这一建议的主要目标包括群体细胞的生理特征以及对RSP趋光行为的分析。百分制。此外，还将进行群体细胞形成和趋光性的遗传分析，以确定参与这些过程的遗传基因座的数量和性质。这些研究还将通过所涉及的光感受器(S)的生化和分子遗传特征来加强。预计这项拟议的研究将提供有关原核细胞分化的重要信息，此外，还将提供真细菌趋光性机制的第一个分子分析。我们还建议将细菌光合作用的遗传分析扩展到进化上不同种类的优生细菌光养生物。本研究的目的是从毛状氯杆菌、幽门螺杆菌、绿色红假单胞菌和蓝藻中获得细菌-叶绿素生物合成基因的克隆，以确定光合作用基因簇在不同属和种的光养原核生物中的保守程度。获得的克隆还将用于对细菌和植物叶绿素生物合成途径共同的遗传位点进行序列分析，以用于后续植物系统中叶绿素生物合成的研究。***