Regulation of Light Directed Movement in Cyanobacteria

蓝藻中光定向运动的调节

• 批准号: 0110544
• 负责人: Devaki Bhaya
• 金额: $ 36.95万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-15 至 2005-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0110544&HistoricalAwards=false
• 关键词: Regulation; Light; Directed; Movement; Cyanobacteria

Cyanobacteria can survive and flourish in a broad range of environments, and often dominate in marine habitats as well as in microbial mats and biofilms. Their ubiquitous global distribution reflects, in part, their ability to cope with wide fluctuations in temperature, nutrient, and light levels. Dr. Bhaya is particularly interested in the ability of cyanobacteria to perceive and move towards or away from a light source and thereby optimize conditions for photosynthesis. This project will help the scientific community understand the molecular basis of this critically important trait.This phenomenon, termed phototaxis, is well-known but little understood. Recently Dr.Bhaya and her colleagues have demonstrated that phototaxis in Synechocystis is a surface-dependent phenomenon that requires type IV pili, surface appendages implicated in both twitching and social motility and the association of bacterial pathogens with their hosts. This investigator has taken advantage of the fact that the Synechocystis genome has been entirely sequenced to generate a library of tagged motility mutants. She will focus her work on a class of mutants that map to chemotaxis-like (che) genes. While the role of chemotaxis proteins is fairly well-understood in enteric bacteria, it is not clear whether many of the paradigms that have been established extend to the operation of Che proteins in other systems. Synechocystis has at least three che loci, two of which are involved in motility responses. Furthermore, one of the mutants that the investigator has isolated has a lesion in a gene encoding a protein with a domain reminiscent of the chromophore-binding domain of phytochrome in vascular plants. To elucidate the elements involved in generating and controlling motility, Dr.Bhaya will use time-lapse video microscopy to record movement in real time in both wild type and mutant strains. This will allow her to observe, for the first time, movement of single cells and cell populations, and thus to ask fundamental questions about the parameters that govern motility. The second aspect of the work is to use molecular and biochemical tools to tag and/or mutate specific proteins, such that the interactions among the proteins that regulate phototaxis can be better understood.

蓝藻可以在广泛的环境中生存和繁衍，并且通常在海洋栖息地以及微生物垫和生物膜中占主导地位。它们在全球范围内无处不在，这在一定程度上反映了它们应对温度、养分和光照水平大幅波动的能力。 Bhaya 博士对蓝藻感知光源、靠近或远离光源从而优化光合作用条件的能力特别感兴趣。 该项目将帮助科学界了解这一至关重要的性状的分子基础。这种称为趋光性的现象众所周知，但知之甚少。最近，Bhaya 博士和她的同事们证明，集胞藻的趋光性是一种表面依赖性现象，需要 IV 型菌毛、涉及抽搐和社会运动以及细菌病原体与其宿主关联的表面附属物。该研究人员利用集胞藻基因组已完全测序的事实来生成标记的运动突变体文库。 她将把工作重点放在一类映射到趋化性 (che) 基因的突变体上。虽然趋化蛋白在肠道细菌中的作用已得到相当多的了解，但尚不清楚已建立的许多范例是否可以扩展到其他系统中 Che 蛋白的操作。集胞藻至少有三个基因座，其中两个与运动反应有关。此外，研究人员分离出的突变体之一在编码蛋白质的基因中存在损伤，该蛋白质的结构域让人想起维管植物光敏色素的发色团结合结构域。 为了阐明参与产生和控制运动的元素，Bhaya 博士将使用延时视频显微镜实时记录野生型和突变株的运动。这将使她第一次观察到单细胞和细胞群的运动，从而提出有关控制运动的参数的基本问题。该工作的第二个方面是使用分子和生化工具来标记和/或突变特定蛋白质，以便更好地理解调节趋光性的蛋白质之间的相互作用。