Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
Environ Microbiol. 2018 Mar;20(3):1283-1295. doi: 10.1111/1462-2920.14074. Epub 2018 Mar 14.
The ability to survive conditions of low water activity is critical for the survival of many bacteria in the environment and facilitates disease transmission through food and contaminated surfaces. However, the molecular mechanisms that enable bacteria to withstand this condition remain poorly understood. Here we describe a network of regulators in Escherichia coli that are important for this bacterium to survive dehydration. We found that the transcriptional regulator DksA and the general stress response regulator RpoS play a critical role. From a plasmid genomic library screen, we identified two additional regulators, Crl and ArcZ, that promote dehydration tolerance through modulation of RpoS. We also found that LexA, RecA and ArcA contribute to survival. Our results identify key regulators that enable E. coli to tolerate dehydration and suggest a hierarchical network is involved in protection against cellular damage associated with this stress.
在低水活度条件下生存的能力对许多环境中的细菌的生存至关重要，并通过食物和受污染的表面促进疾病传播。然而，使细菌能够耐受这种条件的分子机制仍知之甚少。在这里，我们描述了大肠杆菌中一组对其脱水生存至关重要的调控因子。我们发现转录调控因子 DksA 和一般应激反应调控因子 RpoS 发挥了关键作用。通过质粒基因组文库筛选，我们发现了另外两个调控因子 Crl 和 ArcZ，它们通过调节 RpoS 促进脱水耐受性。我们还发现 LexA、RecA 和 ArcA 有助于存活。我们的结果确定了使大肠杆菌能够耐受脱水的关键调控因子，并表明一个分层网络参与了对与这种应激相关的细胞损伤的保护。
