Swimming, Swarming, or Sticking in Vibrio Parahaemolyticus

智力优势是什么调节过程决定了细菌是选择在液体中游动，是选择诱导特定的群集细胞程序以在表面上移动并定植，还是选择变得不那么移动而更粘接以形成生物膜？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，因为对这种生物来说，游泳、群集和精通粘性生物膜的细胞之间的区别是非常深刻的。表面相关的生长促进了基因表达的全局、全基因组重编程，导致细胞类型的改变，并诱导了游泳细胞不表达的全新运动系统。这个交替的系统允许在表面上极其快速的移动，这被称为群体。表面的生长也会导致强健的生物膜的形成。已经确定了在响应表面生长时相互调节的基因组；特别是运动和粘附基因以及控制这些基因表达的调控基因。这些调节基因被命名为scr，编码含有GGDEF和EAL特征域的潜在信号转导蛋白，它们具有酶活性，导致信号核苷酸c-di-GMP的合成和降解。本项目主要研究c-di-GMP在编程基因表达和行为中的作用。据推测，一组特定的Scr信号转导蛋白能够通过调节c-di-GMP水平来检测和整合各种环境信号，从而影响蜂群或粘附的决定。低浓度的c-二- gmp有利于表面迁移；然而，高水平的这种核苷酸促进了更具黏附性和无根性的细胞类型，或生物膜熟练的细胞类型。本项目重点研究：1、通过基因筛选检测潜在的scr传感器和荧光融合蛋白确定蛋白定位，明确scr c-di-GMP网络的范围；2、通过检测候选的蜂群和粘附转录调控因子，建立c-di-GMP调控基因表达的分子基础。因此，本研究旨在绘制细菌感知、整合和响应环境中多种信号的复杂调控回路控制过程，并将为细菌如何做出决策提供见解。这些研究将揭示使细菌能够成功定殖在表面的发育过程的一般原理，并指出副溶血性弧菌利用的特定表面适应策略。本项目旨在通过实施本科生驱动的发现项目来整合教学和研究，以检查环境信号输入并定义新的输出目标。这个发现计划将允许本科生直接参与研究过程。学生们将学会观察、提出假设并检验自己的想法；他们也将发展他们的写作和公共演讲技巧。重要的是，学生项目的制定方式也将使学生获得广泛的遗传、生理、分子生物学和基于生物信息学的技术知识，这些技术可用于揭示基因控制程序和细菌行为的潜在基础。

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.