Bacterial persistence and proton-motive force

摘要 细菌持久性是细菌在抗生素压力下生存的一种强大机制，而且 很可能是慢性感染的主要原因。细菌的持久者与其他细菌在基因上是模糊的 种群，很可能是由于固有的随机表型变异而出现。尽管所有主要的 细菌病原体产生持久者，持久者的机制尚不清楚。持之以恒的人会这样做 没有表现出与其他细胞群体的任何明显的形态差异。这增加了 研究持久菌如何在自然细菌种群中出现的挑战。在已知的机制中 涉及毒素-抗毒素(TA)模块，它消散质子动力(PMF)并促进持久性 队形。持续体也可能是由于能量缺乏而产生的，这会导致细胞休眠。然而， 持久种群在许多方面是非常不同的，并确定了持久的机制 将继续具有挑战性，直到异质性的来源被确定。在拟议的工作中， 目的是量化持久者PMF的异质性，并研究影响适合度的关键因素 永久种群。我们的长期目标是发展对随机性的机械性理解 支配持久性的现象。拟议的工作具有创新性，因为它结合了单细胞生物物理 包括荧光技术的光学捕获和定量图像分析在内的分析-这些工具 将被用来量化PMF中可能盛行于Eschericia持久种群的异质性 Coli.提出的创新方法也将有助于测试被测量对象之间的相关性 不同抗生素胁迫下的异质性和持久性的发生。尤其是中央， 低能级可以预测持久形成的可能性的假设将得到检验。成功 该项目的实施将为未来确定细菌能量学如何影响 持久性机制。由于坚持者可能在疾病的临床复发中发挥重要作用，他们是一种 对公共医疗造成重大负担。再加上新出现的抗生素耐药性威胁，使得 提出的工作及时而关键。

ABSTRACT Bacterial persistence is a robust mechanism employed by bacteria to survive antibiotic stress, and is likely to be a major cause of chronic infections. Bacterial persisters are genetically indistinct from the rest of the population, and likely emerge due to phenotypic variations that are inherently stochastic. Although all major bacterial pathogens produce persisters, the mechanisms of persistence are poorly understood. Persisters do not exhibit any discernible morphological differences from the rest of the cell population. This adds to the challenges of studying how persisters emerge in natural bacterial populations. Among the known mechanisms involve toxin-antitoxin (TA) modules, which dissipate the proton-motive force (PMF) and promote persister formation. Persisters may also arise due to energetic deficiencies, which induce dormancy in cells. However, persister populations are quite heterogeneous in many regards and identifying the mechanisms of persistence will continue to remain challenging until the sources of heterogeneity are determined. In the proposed work, the objective is to quantify the heterogeneity in the PMF of persisters and study key factors that influence fitness in persister populations. The long-term goal is to develop a mechanistic understanding of the stochastic phenomenon governing persistence. The proposed work is innovative as it combines single-cell biophysical assays including optical trapping with fluorescence techniques and quantitative image analysis – these tools will be used to quantify the heterogeneities in the PMF that might prevail in persister populations of Escherichia coli. The innovative approaches proposed will also help test correlations between the measured heterogeneities and the occurrence of persistence under different antibiotic stresses. In particular, the central hypothesis that low energy levels can predict the probability of persister formation will be tested. Successful execution of this project will lay the foundation for future efforts to determine how bacterial energetics influence persistence mechanisms. As persisters likely play a major role in clinical recurrence of disease, they are a major burden on the public healthcare. This coupled with the emerging threat of antibiotic resistance makes the proposed work timely and critical.