Evolution of bacterial communication systems

细菌通讯系统的进化

• 批准号: 10703396
• 负责人: Samantha Wellington Miranda
• 金额: $ 12.5万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-12 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10703396
• 关键词: Advisory Committees; Affect; Amino Acid Sequence; Amino Acids; Antibiotics; Architecture; Award; Bacteria; Bacterial Physiology; Behavior; Biological Models; Biostatistical Methods; Cell Density; Cell Membrane Permeability; Characteristics; Clinical; Coculture Techniques; Communication; Communities; Complement; Complex; Costs and Benefits; Coupled; DNA Sequence; Data Set; Engineering; Ensure; Environment; Equilibrium; Evolution; Faculty; Foundations; Funding; Future; Gene Activation; Gene Expression; Genes; Goals; Growth; Human; Hypersensitivity; Impairment; In Vitro; Infection; Knowledge; Measures; Mentors; Mentorship; Microbial Biofilms; Modeling; Organism; Phase; Physiology; Positioning Attribute; Postdoctoral Fellow; Predisposition; Production; Property; Proteins; Proteobacteria; Pseudomonas aeruginosa; Regulon; Research; Research Proposals; Role; Signal Transduction; Signaling Molecule; System; Testing; Toxin; Training; Variant; Virulence; Work; bacterial community; behavior influence; career development; cytosolic receptor; experience; experimental study; fitness; homoserine lactone; insight; intercellular communication; laboratory experiment; metagenome; multidisciplinary; mutant; non-Native; opportunistic pathogen; pathogen; pathogenic bacteria; premature; pressure; programs; quorum sensing; receptor; receptor sensitivity; response; skills; small molecule; tool; transcription factor

PROJECT SUMMARY/ ABSTRACT Quorum sensing (QS) is an important form of bacterial communication used to coordinate gene expression and group behaviors in a cell density-dependent manner. Many bacteria use a form of QS in which a signal synthase produces a membrane-permeable small molecule to which a paired cytosolic receptor responds. Hundreds of QS systems with diverse properties have been identified, many of which are important for the virulence of pathogenic bacteria. How this diversity evolved is a question of fundamental importance to the field. In my early postdoctoral work on the model QS system LasI-LasR from Pseudomonas aeruginosa, I observed that the receptor, LasR, has not evolved to maximal signal sensitivity and that variants of both LasI and LasR tend to be less selective than wildtype. Further, QS systems are often tightly regulated to ensure activity only occurs at a specific cell density. Based on these observations, I hypothesize that QS systems evolve to balance signal sensitivity, selectivity, and fitness. This proposal tests that hypothesis using the LasI-LasR model system. Aim 1 will investigate the costs and benefits of signal sensitivity using hyper- and hypo-sensitive LasR variants I identified previously. I will measure the timing and level of QS activity in these mutants, the susceptibility of the mutants to signal interference, and ultimately the fitness of the mutants in monoculture and in competition with wildtype P. aeruginosa. Aim 2 will evaluate how P. aeruginosa responds to pressure on LasI-LasR signal selectivity. I will use my recently identified non-selective LasI and LasR variants as a starting point for the in vitro evolution of new signal selectivity. This aim will illuminate additional determinants of QS selectivity and will generate tools for future research on the trajectory by which QS signal selectivity evolves. Together these aims will deepen our understanding of the evolution of bacterial communication systems, are expected to facilitate future research into the roles of these systems in polymicrobial communities, and will lead to new avenues for understanding and treating infections. This research proposal will form the foundation of my applications for an independent faculty position and the results I obtain are expected to help me successfully compete for future funding. These experiments will be initiated during the K99 phase of the award and will include training in bacterial co-culture, in vitro evolution, and biostatistical methods. Additionally, this proposal includes a career development and training plan to complement my prior experience. I have assembled a multidisciplinary advisory team to help me achieve my goals and my mentor, Dr. Greenberg, is a pioneer and expert in bacterial communication with a long track record of successful mentorship. The training and support provided by this award will enable me to achieve my long-term goal of establishing an independent research program focused on bacterial signaling and physiology in complex environments.

项目概要/摘要 群体感应（QS）是细菌通讯的一种重要形式，用于协调基因表达和 以细胞密度依赖的方式进行群体行为。许多细菌使用一种 QS 形式，其中信号合酶 产生一种可渗透膜的小分子，配对的胞质受体对其做出反应。数百个 已鉴定出具有多种特性的 QS 系统，其中许多特性对于细菌的毒力很重要 致病菌。这种多样性如何演变是该领域的一个至关重要的问题。在我的早期 博士后研究铜绿假单胞菌 QS 系统 LasI-LasR 模型时，我观察到 受体 LasR 尚未进化到最大信号敏感性，并且 LasI 和 LasR 的变体往往是 选择性低于野生型。此外，QS 系统通常受到严格监管，以确保活动仅发生在 特定细胞密度。基于这些观察，我假设 QS 系统进化到平衡信号 敏感性、选择性和适应性。该提案使用 LasI-LasR 模型系统测试该假设。目标1 将研究使用高敏感度和低敏感度 LasR 变体 I 的信号敏感度的成本和收益 先前已识别。我将测量这些突变体中 QS 活动的时间和水平，以及这些突变体的易感性 突变体发出信号干扰，最终影响突变体在单一栽培中的适应性以及与其他物种的竞争 野生型铜绿假单胞菌。目标 2 将评估铜绿假单胞菌如何响应 LasI-LasR 信号压力 选择性。我将使用我最近发现的非选择性 LasI 和 LasR 变体作为体外实验的起点 新信号选择性的演变。这一目标将阐明 QS 选择性的其他决定因素，并将 为未来研究 QS 信号选择性演变的轨迹生成工具。这些目标共同实现 将加深我们对细菌通讯系统进化的理解，有望促进 未来对这些系统在多微生物群落中的作用的研究，并将带来新的途径 了解和治疗感染。该研究计划将构成我申请的基础 独立的教职职位和我获得的成绩预计将帮助我成功竞争未来 资金。这些实验将在奖励的 K99 阶段启动，并将包括以下方面的培训： 细菌共培养、体外进化和生物统计学方法。此外，该提案还包括职业 发展和培训计划来补充我之前的经验。我整理了一份多学科咨询 团队帮助我实现我的目标，我的导师格林伯格博士是细菌领域的先驱和专家 具有长期成功指导记录的沟通。本次活动提供的培训和支持 该奖项将使我能够实现建立一个独立研究项目的长期目标 复杂环境中的细菌信号传导和生理学。