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The molecular mechanisms and physiological consequences of oxidative stress: lessons from a model bacterium

2013; Nature Portfolio; Volume: 11; Issue: 7 Linguagem: Inglês

10.1038/nrmicro3032

1740-1534

James A. Imlay,

Bacterial Genetics and Biotechnology

To survive in oxic environments, all organisms require mechanisms to degrade toxic reactive oxygen species (ROS). In this Review, James Imlay describes the oxidative stress response ofEscherichia coliand considers the damage caused by ROS and the adaptive strategies used by this bacterium to minimize intracellular ROS accumulation. Oxic environments are hazardous. Molecular oxygen adventitiously abstracts electrons from many redox enzymes, continuously forming intracellular superoxide and hydrogen peroxide. These species can destroy the activities of metalloenzymes and the integrity of DNA, forcing organisms to protect themselves with scavenging enzymes and repair systems. Nevertheless, elevated levels of oxidants quickly poison bacteria, and both microbial competitors and hostile eukaryotic hosts exploit this vulnerability by assaulting these bacteria with peroxides or superoxide-forming antibiotics. In response, bacteria activate elegant adaptive strategies. In this Review, I summarize our current knowledge of oxidative stress in Escherichia coli, the model organism for which our understanding of damage and defence is most well developed.