Stress responses are crucial for bacteria to survive harmful conditions that they encounter in the environment. Although gene regulatory mechanisms underlying stress responses in bacteria have been thoroughly characterised for decades, recent advances in imaging technologies helped to uncover previously hidden dynamics and heterogeneity that become visible at the single-cell level. Despite the diversity of stress response mechanisms, certain dynamic regulatory features are frequently seen in single cells, such as pulses, delays, stress anticipation, and memory effects. Often, these dynamics are highly variable across cells. While any individual cell may not achieve an optimal stress response, phenotypic diversity can provide a benefit at the population level. In this review, we highlight microscopy studies that offer novel insights into how bacteria sense stress, regulate protective mechanisms, cope with response delays, and prepare for future environmental challenges. These studies showcase developments in the single-cell imaging toolbox including gene expression reporters, FRET, super-resolution microscopy, and single-molecule tracking, as well as microfluidic techniques to manipulate cells and create defined stress conditions.

中文翻译：

---

脉冲和延迟，预期和记忆：从单细胞角度观察细菌的应激反应。

压力反应对于细菌在环境中生存的有害条件的生存至关重要。尽管数十年来细菌的应激反应所基于的基因调控机制已被彻底表征，但成像技术的最新进展有助于揭示先前隐藏的动力学和异质性，这些动力学和异质性在单细胞水平上变得可见。尽管应激反应机制各不相同，但某些动态调节功能还是经常在单个细胞中看到，例如脉冲，延迟，应激预期和记忆效应。通常，这些动力学在细胞之间变化很大。尽管任何单个细胞都可能无法达到最佳的应激反应，但表型多样性可以在种群水平上带来益处。在这篇评论中 我们重点介绍了显微镜研究，这些研究为细菌如何感测压力，调节保护机制，应对响应延迟以及为未来的环境挑战做准备提供了新颖的见解。这些研究展示了单细胞成像工具箱中的发展，包括基因表达报告子，FRET，超分辨率显微镜和单分子跟踪，以及用于控制细胞和创建确定的应激条件的微流体技术。