Swimming, Swarming, or Sticking in Vibrio Parahaemolyticus

副溶血性弧菌中的游泳、聚集或粘附

• 批准号: 0817593
• 负责人: Linda McCarter
• 金额: $ 44.98万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0817593&HistoricalAwards=false
• 关键词: Swimming; Swarming; Sticking; Vibrio; Parahaemolyticus

Intellectual Merit What regulatory processes govern whether a bacterium chooses to swim in liquid, to induce the specific swarmer cell program in order to move over and colonize surfaces, or to become less mobile and more adhesive in order to form biofilms? The marine bacterium Vibrio parahaemolyticus is an excellent model organism in which to address this question because the distinctions between the swimming, swarming, and sticky biofilm-proficient cells are very profound for this organism. Surface-associated growth promotes global, genome-wide reprogramming of gene expression resulting in an altered cell type and the induction of an entirely new motility system that is not expressed by the swimmer cell. This alternate system allows extremely rapid movement over surfaces, which is called swarming. Growth on surfaces can also result in robust biofilm formation. Gene sets have been identified that are reciprocally regulated in response to growth on surfaces; specifically motility and adhesive genes as well as the regulatory genes that govern the expression of these gene sets. These regulatory genes, named scr, encode potential signal transduction proteins containing GGDEF and EAL signature domains, which possess enzymatic activities causing synthesis and degradation of the signaling nucleotide c-di-GMP. This project focuses on the role of c-di-GMP in programming gene expression and behavior. It is hypothesized that a specific array of Scr signal transducing proteins, capable of detecting and integrating diverse environmental signals by modulating the level of c-di-GMP, influences the decision to swarm or stick. A low concentration of c-di-GMP favors surface mobility; whereas high levels of this nucleotide promote a more adhesive and sessile, or biofilm-proficient, cell type. This project focuses on: 1, defining the scope of the scr c-di-GMP network by using genetic screens to detect potential scr sensors and fluorescent fusion proteins to determine protein localization; and 2, establishing the molecular basis of c-di-GMP control of gene expression by examining candidate transcriptional regulators of swarming and sticking. Thus, this research is designed to map a complex regulatory circuit controlling processes by which bacteria sense, integrate, and respond to multiple signals in their environment, and will provide insight into how bacteria make decisions.Broader Impact These studies will reveal general principles with respect to the developmental program that enables bacteria to successfully colonize surfaces, as well as indicate the specific surface-adaptation strategies utilized by V. parahaemolyticus. This project is specifically designed to integrate teaching and research by implementing an undergraduate-driven discovery project to examine environmental signal input and define new output targets. This discovery plan will allow the direct participation of undergraduate students in the research process. Students will learn to make observations, formulate hypotheses and test their ideas; they will also develop their writing and public speaking skills. Importantly, the student projects are formulated in such a manner that the students will also gain knowledge of the broad arsenal of genetic, physiological, molecular biological, and bioinformatics-based techniques that can be applied to unravel programs of gene control and the underlying basis for bacterial behavior.

知识价值是什么调控过程决定了细菌是选择在液体中游泳，还是诱导特定的游动细胞程序在表面移动和定居，还是为了形成生物膜而变得更少移动和更具粘附性？海洋细菌副溶血性弧菌是解决这个问题的一个很好的模式生物，因为游泳、集群和粘性生物膜熟练细胞之间的区别对这种生物来说是非常深刻的。表面相关生长促进了基因表达的全球、全基因组重新编程，导致了细胞类型的改变，并诱导了一个全新的运动系统，而游泳者细胞并不表达这种运动系统。这种替代系统允许在表面上极快地移动，这被称为蜂群。在表面的生长也可以导致强大的生物膜形成。已经确定了与表面生长相互调控的基因组；特别是运动性和粘附性基因，以及控制这些基因组表达的调控基因。这些调控基因称为SCR，编码含有GGDEF和EAL特征结构域的潜在信号转导蛋白，具有导致信号核苷酸c-di-GMP合成和降解的酶活性。这个项目的重点是c-di-GMP在基因表达和行为编程中的作用。假设一个特定的SCR信号转导蛋白阵列，能够通过调节c-di-GMP的水平来检测和整合不同的环境信号，影响集群或粘连的决定。低浓度的c-di-GMP有利于细胞表面的流动性；而高浓度的c-di-GMP则促进更多的粘附性和固位性，或生物膜熟练的细胞类型。本项目的重点是：1，通过遗传筛选来检测潜在的SCR传感器和荧光融合蛋白来确定蛋白质定位，从而确定SCR c-di-GMP网络的范围；2，通过检测群集和粘连的候选转录调控因子，建立c-di-GMP控制基因表达的分子基础。因此，这项研究旨在绘制一个复杂的调控电路，控制细菌感知、整合和响应环境中的多种信号的过程，并将为细菌如何做出决定提供洞察。广泛影响这些研究将揭示关于使细菌能够成功在表面定植的发育程序的一般原理，以及副溶血性弧菌利用的特定表面适应策略。这个项目是专门设计的，通过实施一个本科生驱动的发现项目来检查环境信号输入并定义新的输出目标，从而将教学和研究结合起来。这一发现计划将允许本科生直接参与研究过程。学生将学会观察、提出假设和检验自己的想法；他们还将发展写作和公开演讲的技能。重要的是，学生项目的制定方式使学生还将获得基于遗传学、生理学、分子生物学和生物信息学的广泛武器库的知识，这些技术可以应用于揭开基因控制程序和细菌行为的潜在基础。