Collaborative research: Short-circuiting in bacterial quorum sensing

合作研究：细菌群体感应的短路

• 批准号: 1158553
• 负责人: Martin Schuster
• 金额: $ 50.45万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1158553&HistoricalAwards=false
• 关键词: Collaborative; research; Short; circuiting; bacterial

Intellectual meritBacterial cell-cell communication, also termed quorum sensing (QS) is a wide-spread process that coordinates multicellular behaviors such as virulence, biofilm formation, and nutrient acquisition in response to cell density, population structure and environmental viscosity. There has been an explosion in research directed at understanding the molecular mechanisms of QS, but there is a paucity of information on the ecophysiological implications and on the emergent properties of QS regulatory networks. The current project addresses this need by combining genetics, physiology, and systems biology in understanding QS in the model bacterium Pseudomonas aeruginosa. This bacterium communicates via diffusible acyl-homoserine lactone signals to control the expression of hundreds of genes. The particular focus is on two central properties of the P. aeruginosa QS network, antiactivation and co-regulation. Antiactivation, initially characterized in the plant pathogen Agrobacterium tumefaciens, inhibits the activity of cognate QS receptors through direct protein-protein interaction. Co-regulation permits the integration of other environmental signals into the quorum response. A key feature here is the starvation-dependent transcription of the main P. aeruginosa QS receptor, LasR. Because several QS-controlled products are costly extracellular enzymes involved in nutrient acquisition, co-regulation by starvation appears ecologically worthwhile. The roles of antiactivation and lasR regulation in modulating the quorum response and in preventing "short-circuiting" will be investigated. Short-circuiting, or self-induction, is a major unanswered question in bacterial QS: How is it that diffusible quorum-signals do not immediately bind to their cognate receptors in the same cell in which they are produced and activate gene expression independent of cell density? Based on recent modeling data, the PIs hypothesize that antiactivation and lasR regulation help prevent short-circuiting, and that the tight environmental control of lasR expression is key in modulating quorum responses that are either short-circuited, triggered by cell density, or triggered by starvation. The specific aims of the project, which integrate experimentation and computational modeling, are therefore to (1) directly observe short-circuiting of QS target gene expression in antiactivator-deficient and lasR overexpressing cells, (2) investigate the growth-rate dependence of QS gene induction and short-circuiting in wild-type cells, and (3) develop a model of the las QS network that, in addition to antiactivation and co-regulation, incorporates and evaluates key properties such as receptor-QS signal interaction, receptor dimerization, autoregulation, and active efflux. Broader impactsResearch. The research conducted by the PIs over the last decade, funded in part by NSF, has established P. aeruginosa QS as a global regulatory network, has provided insight into the function of the central QS regulator LasR, has demonstrated that QS is a cooperative behavior subject to social conflict, and has resulted in the first computational model of P. aeruginosa QS. The current project will incorporate and extend these findings to understand the basic design features of a QS network, including antiactivation and the integration of environmental cues. The work will broadly benefit and will find application in synthetic biology and biotechnology for the design of novel genetic response circuits. Education. The described project provides excellent educational opportunities for students. The PIs have and will continue to train graduate and undergraduate students. Dr. Schuster will also provide educational opportunities for high-school students through the Apprenticeship for Science and Engineering, an established summer internship program at Oregon State University. Many of the proposed experiments are conceptually and technically straight-forward and are particularly well suited for the engagement of high-school and undergraduate students in the scientific process.

智力绩效细胞 - 细胞 - 也称为法规传感（QS）是一个广泛的过程，它可以协调多细胞行为，例如毒力，生物膜形成和养分，以响应细胞密度，人群结构和环境粘度。 旨在理解QS的分子机制的研究中发生了爆炸，但是关于生态生理学意义以及QS调节网络的新兴特性的信息很少。当前的项目通过将遗传学，生理学和系统生物学结合在了解模型细菌铜绿假单胞菌中的QS中来满足这一需求。该细菌通过可扩散的酰基 - 耶洛舍碱内酯信号传达，以控制数百个基因的表达。特别的重点是铜绿假单胞菌QS网络的两个中心特性，抗活化和共调节。最初在植物病原体农业杆菌中表征的抗活化，通过直接蛋白质 - 蛋白质相互作用抑制了同源QS受体的活性。 共同调节允许将其他环境信号集成到法定人数响应中。 这里的关键特征是铜绿假单胞菌QS受体LASR的饥饿依赖性转录。 由于几种QS控制的产品是参与营养习得的昂贵的细胞外酶，因此在生态上似乎值得饥饿。 将研究抗活化和LASR调节在调节法定人数反应和防止“短路”中的作用。 短路或自我诱导是细菌QS中的主要未解决问题：在同一细胞中不会立即与其产生的基因表达和激活基因表达无关的基因表达，而独立于细胞密度的基因表达是如何立即与其同源受体结合的？ 基于最近的建模数据，PIS假设抗活菌和LASR调节有助于防止短路，而LASR表达的紧密环境控制对于调节群体响应的关键是调节短路，由细胞密度触发的短路，或者是由饥饿触发的。因此，该项目的具体目的是整合实验和计算模型，因此（1）直接观察QS目标基因表达在抗激活因缺乏症和LASR过表达的细胞中的短路，（2）研究QS基因诱导和短路的生长速率依赖性在野生型细胞和（3）中的QS基因诱导和短路，并在野生型细胞中添加了（3）QS QS QS QS QS QS的QS QS QS Q. 3）共同调节，结合并评估关键特性，例如受体QS信号相互作用，受体二聚体，自动调节和主动排出。更广泛的影响力搜索。 PIS在过去的十年中进行的一部分由NSF资助，由NSF资助，已将P. eruginosa QS建立为全球监管网络，已提供了对中央QS调节器LASR的功能的见解，证明了QS是符合社会冲突的合作行为，并且已经在P. eruguginosa Qs QS QS的首次计算模型中产生。当前的项目将结合并扩展这些发现，以了解QS网络的基本设计特征，包括抗激活和环境提示的整合。这项工作将广泛受益，并将在合成生物学和生物技术中找到用于设计新遗传反应电路的应用。 教育。所描述的项目为学生提供了极好的教育机会。 PIS并将继续培训毕业生和本科生。 Schuster博士还将通过俄勒冈州立大学的一项既定的暑期实习计划科学与工程学徒制，为高中生提供教育机会。许多拟议的实验在概念和技术上都是直截了当的，并且特别适合在科学过程中投入高中和本科生。