Identifying the mechanisms of mechanosensing by the bacterial flagellar motor

项目摘要/摘要 自由游动的细菌以生物膜或菌群的形式在表面定植是 许多细菌感染，但细菌如何感知表面仍不清楚。细菌鞭毛马达具有 成为表面传感领域的关键参与者。传统上被认为只涉及通过旋转螺旋运动 细丝，新的证据表明，马达作为机械传感器来感知细菌表面 互动。然而，运动介导的机械感觉通路的组件很大程度上仍然 身份不明。为了制定有效的战略来预防和治疗有害生物膜，迫切需要 了解马达如何感知力并将信息传递给下游过程。目标是 这一建议的目的是描述电机介导的机械传感及其相关电路的功能。 这项拟议的工作将利用新的生物物理方法来精确控制作用于 并测量电机的响应。以往的结果和初步数据表明，电机自适应 通过产生扭矩的定子单元的动态自组装改变其扭矩输出来加载，提供 一种可能的机械接收机制。在信号转导方面，目前还不清楚 机械感应信息从马达传输到生物膜形成途径，生物膜形成途径受到调节。 通过细菌第二信使环二鸟酸酯(c-di-GMP)。中心假设是机械的 对马达的刺激会激活局部和整体反应，从而触发c-di-GMP信号。中环 假说将通过实验表征电机的机械接收和使用高通量来检验 描述机械转导途径的遗传学。这些目标将利用生物物理、 成像、分子和基因组工具。这项工作的预期结果是更好地理解 细菌的鞭毛马达参与了表面感知。长期目标是研究细菌是如何产生 使用简单的分子结构来实现复杂的行为。该职业发展奖的培训阶段 概述了获得技术和专业技能的全面计划，以使PI能够 过渡到独立的研究岗位。该项目的成功完成将提供一个平台 未来的研究旨在揭示分子相互作用和潜在的物理生物学，使 细菌行为复杂，如生物被膜形成。

PROJECT SUMMARY/ABSTRACT Surface colonization in the form of biofilms or swarms by otherwise free-swimming bacteria is the first step in many bacterial infections, but how bacteria sense surfaces remains unknown. The bacterial flagellar motor has emerged as a key player in surface sensing. Seen traditionally as involved only in motility by rotating helical filaments, new evidence suggests that the motor acts as a mechanosensor to sense bacterial surface interactions. However, the components of the motor-mediated mechanosensing pathway largely remain unidentified. To develop effective strategies for preventing and treating harmful biofilms, there is a critical need to understand how the motor senses forces and transmits information to downstream processes. The objective of this proposal is to characterize the function of motor-mediated mechanosensing and its associated circuitry. The proposed work will utilize novel biophysical methods to precisely control the mechanical load acting on the motor and to measure the motor’s response. Previous results and preliminary data show that the motor adapts to load by changing its torque output via the dynamic self-assembly of torque-generating stator units, providing a possible mechanism for mechanoreception. On the signal transduction side, it is unclear how the mechanosensing information is transmitted from the motor to the biofilm formation pathways, which are regulated by the bacterial second messenger cyclic diguanylate (c-di-GMP). The central hypothesis is that mechanical stimulation of the motor activates local and global responses that trigger c-di-GMP signaling. The central hypothesis will be tested by experimentally characterizing motor mechanoreception and using high-throughput genetics to delineate the mechano-transduction pathways. These goals will utilize a combination of biophysical, imaging, molecular, and genomic tools. The expected outcome of this work is an improved understanding of how the flagellar motor of bacteria is involved in surface sensing. The long-term goal is to study how bacteria generate complex behaviors using simple molecular machinery. The training phase of this career development award outlines a comprehensive plan for the acquisition of technical and professional skills that will enable the PI’s transition into an independent research position. The successful completion of this project will provide a platform for future research aimed at revealing the molecular interactions and the underlying physical biology that enable complex bacterial behavior such as biofilm formation.