Bacterial persistence and proton-motive force

摘要 细菌持久性是细菌在抗生素胁迫下生存的一种稳健机制， 可能是慢性感染的主要原因。细菌坚持者在遗传上与其余的细菌没有区别。 群体，并可能出现由于表型变异，这是固有的随机性。虽然所有主要 细菌病原体产生持久性，持久性的机制知之甚少。佩瑟斯特斯做的 与细胞群的其余部分没有表现出任何可辨别的形态学差异。这增加了 研究持留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，其消散质子动力（PMF）并促进持久性 阵宿存也可能是由于能量不足引起的，这会诱导细胞休眠。然而，在这方面， 持久性种群在许多方面是相当异质的， 在异质性的来源被确定之前，将继续保持挑战性。在拟议的工作中， 目的是量化持久者PMF的异质性，并研究影响适应性的关键因素。 持久种群。长期的目标是发展一个机械的理解随机 持续性现象。拟议的工作是创新的，因为它结合了单细胞生物物理 分析包括具有荧光技术的光学捕获和定量图像分析-这些工具 将用于量化可能在大肠杆菌持久种群中流行的PMF中的异质性 杆菌所提出的创新方法也将有助于测试所测量的 异质性和不同抗生素胁迫下持久性的发生。特别是中央 将检验较低能量水平可以预测持久性形成的概率的假设。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起主要作用，因此它们是一种 这是公共医疗的沉重负担。再加上抗生素耐药性的威胁， 提出的工作及时和关键。

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.