Various stresses affect rpos transcription differently with or without the aid of other cellular regulatory proteins. RpoS con trols transcription of more than 35 genes and plays a key role in stationary phase stress response as well as most other stress re- sponses, but other sigma factors and regulatory systems are also coordinated with specific physical stresses. A diagram of general stress response in E. coli is described in Figure 1. The regulatory aspect of each physical stress is discussed as follows.