Genetic Control of Growth on Surfaces

表面生长的遗传控制

• 批准号: 0077327
• 负责人: Linda McCarter
• 金额: $ 37.76万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0077327&HistoricalAwards=false
• 关键词: Genetic; Control; Growth; Surfaces

V. parahaemolyticus is adapted to communal life on surfaces. When grown on a surface or in a viscous layer, the organism induces a large gene system and differentiates into a swarmer cell. Differentiation to the swarmer cell allows movement over surfaces and through viscous environments. Cells recognize each other, and movement is coordinated or social in nature, resulting in complex multicellular behavior and growth in organized communities. The swarmer cell is well-equipped to move over and colonize surfaces: it is elongated and hyperflagellated. The focus of this work is to unravel the regulatory networks that participate in the surface-adapted lifestyle in order to gain insight into how bacteria form and maintain communities on surfaces. The hypothesis is that different gene sets are turned on and off during the development of these communities. One large set, encoding the lateral flagellar motility system, is known. The first aim will be to identify genes induced by growth on surfaces; a novel transposon and delivery system has been designed to implement search for surface-induced genes. Completion of this aim will result in the identification of genes involved in the lateral flagellar hierarchy, which has not been systematically dissected, and new genes not required for motility but pertinent to the surface-adapted lifestyle. A comprehensive picture of gene activity (gene identity and timing of expression) of surface-attached bacteria will be developed; this will likely reveal the existence of interconnecting regulatory circuits to coordinate gene expression. The second aim focuses on one potential circuit that has recently been discovered. Mutations in two linked operons cause uninducible expression of swarmer cell genes. One operon (fim) encodes a fimbrial-like chaperone-usher pair and proteins that may be outer-membrane associated. The second operon (fli) encodes an ABC periplasmic-type binding protein (similar to Escherichia coli FliY) and a product that resembles a number of proteins in the GGDEF-type sensor family. The interactions between these gene sets and swarmer cell differentiation will be dissected by using a combination of mutagenesis, overexpression, and protein localization experiments. These studies should define gene activity pertinent to growth on surfaces and trace the network of regulatory circuitry that enables bacteria to establish growth and develop communities on surfaces. Understanding the pattern of surface-induced gene expression should reveal important principles about how bacteria adapt to their environment, coordinate behavior, and develop structured communities or biofilms. Moreover, this project will have significant educational impact for genetic analysis in Vibrio, specifically transposon mutagenesis and the genome-wide search for surface-controlled genes, will be used as an undergraduate and graduate level teaching tool.

副溶血性弧菌适应于表面上的群体生活。当生长在表面或粘性层中时，生物体诱导一个大的基因系统并分化成蜂群细胞。向群集细胞的分化允许在表面上移动并通过粘性环境。细胞相互识别，运动是协调的或社会性的，导致复杂的多细胞行为和有组织的社区的增长。蜂群细胞装备精良，可以在表面移动和定居：它是细长的和超鞭毛的。这项工作的重点是解开参与表面适应生活方式的调控网络，以深入了解细菌如何在表面形成和维持群落。该假说认为，在这些群落的发育过程中，不同的基因组被打开和关闭。一个大的集合，编码侧鞭毛运动系统，是已知的。第一个目标将是识别表面生长诱导的基因;设计了一种新型转座子和传递系统来搜索表面诱导的基因。这一目标的完成将导致参与侧鞭毛层次，这还没有被系统地解剖，和新的基因不需要运动，但有关的表面适应的生活方式的基因的鉴定。一个全面的图片的基因活性（基因的身份和表达的时间）的表面附着的细菌将开发，这将可能揭示存在的相互连接的监管电路，以协调基因的表达。第二个目标集中在最近发现的一个潜在电路上。两个连锁操纵子的突变导致蜂群细胞基因的不可诱导表达。一个操纵子（fim）编码一个类似菌毛的伴侣-引导蛋白对和可能与外膜相关的蛋白质。第二个操纵子（fli）编码ABC周质型结合蛋白（类似于大肠杆菌FliY）和类似于GGDEF型传感器家族中许多蛋白质的产物。这些基因集和蜂群细胞分化之间的相互作用将通过使用诱变，过表达和蛋白质定位实验的组合进行解剖。这些研究应该确定与表面生长相关的基因活性，并追踪使细菌能够在表面上建立生长和发育群落的调控电路网络。了解表面诱导的基因表达模式应该揭示细菌如何适应环境，协调行为和发展结构化社区或生物膜的重要原则。此外，该项目将对弧菌的遗传分析产生重大的教育影响，特别是转座子诱变和表面控制基因的全基因组搜索，将用作本科生和研究生水平的教学工具。