CAREER: Bacterial heterogeneity in stress survival

细菌持留菌具有令人难以置信的生存压力的能力，是反复细菌感染，抗生素药物治疗失败和抗生素耐药性演变的主要原因。细菌群体中的大多数细胞在暴露于主要压力（如抗生素）时死亡，但一小部分细胞存活很长时间。这些幸存者，也被称为坚持者，似乎是由于整个群体中细胞行为的变异性而产生的。该项目的目标是发现允许细菌持久性的形成，维持和生存的机制，从而帮助理解细菌生存的关键特征。 这项工作将涉及学生研究人员，包括那些来自代表性不足的群体，他们将参与合成生物学研究经验，作为该项目教育目标的一部分。此外，该项目将为K-12科学教师提供专业发展研讨会，以提高他们将合成生物学模块融入课堂的能力。这项研究的总体目标是确定使一些细菌细胞在暴露于压力后存活的机制。有待检验的一个假设是，生存取决于建立某种类型的表观遗传决定的“记忆”的压力，导致更高的持久性数字后，暴露于压力。为了了解使持续生存的长期，致命的压力的监管过程，该项目将使用一套实验方法，如荧光显微镜，微流体，和修改Luria-Delbrück波动测试，与合成生物学和定量建模。此外，转录分析，单细胞实验和高通量技术将用于量化细菌中的表观遗传模式。这项研究将产生一个定量框架，用于理解表型异质性的机制，这种异质性被认为是细菌固有的生存策略。这项工作将影响细菌如何在突然的致命压力下生存以及如何应对恶劣环境波动的基础知识。该研究结果有望为细胞如何从致命压力中恢复的基本分子机制提供新的见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Bacterial persisters have an incredible ability to survive stress and are a major cause of recurrent bacterial infections, failures in antibiotic drug therapy, and evolution of antibiotic resistance. Most cells in a bacterial population die when exposed to a major stress, such as antibiotics, but a small fraction of cells survive for a long time. These survivors, also known as persisters, appear to arise as a result of variability in cell behaviors across the population. The goal of this project is to discover the mechanisms that allow the formation, maintenance, and survival of bacterial persisters and thus to help understand key features of bacterial survival. The work will involve student researchers, including those from underrepresented groups, who will participate in synthetic biology research experiences as part of the project's educational objectives. In addition, the project will provide professional development workshops for K-12 science teachers to enhance their ability to integrate synthetic biology modules into their classrooms. The overall goal of this research is to identify the mechanism that enables some bacterial cells to survive after exposure to stress. One hypothesis to be tested is that survival depends on establishment of some type of epigenetically-determined ‘memory’ of stress that results in higher persister numbers after exposure to the stress. To understand the regulatory processes that enable persisters to survive long-term, lethal stress, the project will use a suite of experimental approaches, such as fluorescence microscopy, microfluidics, and a modified Luria–Delbrück fluctuation test, with synthetic biology and quantitative modeling. In addition, transcriptional analysis, single-cell experiments, and high-throughput techniques will be used to quantify epigenetic patterns in bacteria. The research will produce a quantitative framework for understanding the mechanism responsible for the phenotypic heterogeneity thought to serve as an inherent survival strategy of bacteria. This work will impact fundamental knowledge of how bacteria survive sudden lethal stress and how they deal with harsh environmental fluctuations. The results are expected to offer new insights into the fundamental molecular mechanisms of how cells revive from lethal stress.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.