Stress sensing and processing by bacterial cytoplasmic megacomplexes

项目摘要 细菌可以在非常广泛的快速变化的环境中生长和分裂，适应恶劣的环境。 通过感知外部压力源并应用该信息来建立适当的反应。压力- 传感过程与人类健康有关：具有激活应激反应的病原菌较少 对许多抗菌治疗敏感，每年有近10万美国人死于感染 抗药性细菌事实上，环境抗生素是细菌细胞的一种应激源（在许多应激源中）， 欣然回应。一个持续的挑战是，尽管环境中的分子成分 应激反应系统是众所周知的，但是关于这些应激反应的动力学很少被发现 特别是在单个细胞中。PI将细菌遗传学与微流体技术相结合， 直接观察单细胞谱系在严格控制的环境应激条件下的反应， 揭示了应激反应系统能够引发几种不同的反应， 动力学取决于细胞中存在哪些应力传感器。这些结果提出了额外的基本 问题.位于细胞质中的压力感应蛋白如何有效地响应压力源的发生 细胞外的细胞吗应激反应蛋白的哪些分子特征指定了它们所处的应激源？ 以及它们引发的动态反应模式？不同的动态应力-响应 模式有助于细胞的健康和生存在不利的条件下？拟议的研究解决这些问题 利用枯草芽孢杆菌作为一种高度易处理的环境模型， 应力通过将经典的细菌遗传学、分子技术、荧光显微镜和 微流控技术，这些研究将产生一个新的和更机械的理解的原则， 控制细菌细胞如何感知环境压力，处理这些感觉输入，并产生有效的 反应研究结果将对理解压力反应的一般特征具有广泛的意义 在许多生物系统中。他们还将提供知识，将有助于设计抗菌 干扰环境压力感知的治疗策略。

PROJECT SUMMARY Bacteria can grow and divide in a remarkably wide range of quickly changing environments, adapting to harsh conditions by sensing external stressors and applying that information to mount an appropriate response. Stress- sensing processes are relevant to human health: pathogenic bacteria with activated stress responses are less susceptible to many antimicrobial treatments, and nearly 100,000 Americans die each year from infections with drug-resistant bacteria. Indeed, environmental antibiotics are one stressor (among many) to which bacterial cells readily respond. A persistent challenge has been that, although the molecular components of the environmental stress response system are well known, little has been discovered about the dynamics of these stress responses over time, particularly in individual cells. The PI has combined bacterial genetics with microfluidic technology to directly observe the responses of single-cell lineages under tightly controlled environmental stress conditions, revealing that the stress-response system is capable of eliciting several distinct responses with different dynamics that depend on which stress sensors are present in the cell. These results raise additional fundamental questions. How do stress-sensing proteins located in the cytoplasm effectively respond to the onset of stressors that are outside the cell? Which molecular features of stress-response proteins specify the stressors they respond to and the dynamic response patterns they instigate? How do different dynamic stress-response patterns contribute to cellular fitness and survival in adverse conditions? The proposed studies tackle these questions by taking advantage of the bacterium Bacillus subtilis as a highly tractable model for environmental stress. By bringing together classical bacterial genetics, molecular techniques, fluorescence microscopy, and microfluidic technology, these studies will yield a new and more mechanistic understanding of the principles that govern how bacterial cells sense environmental stress, process those sensory inputs, and produce an effective response. The results will have broad implications for understanding the general features of stress responses across many biological systems. They will also furnish knowledge that will be useful for devising antimicrobial treatment strategies that interfere with environmental stress sensing.