Abrogation of SOS mutagenesis by the

Most bacteria are capable of living and surviving under a wide range of conditions, including exposures to chemical and physical stressors. A key to survival under adverse conditions is their ability to induce specific stress response systems that mitigate harmful effects. Examples are the well-studied SOS system induced under replication stress caused by DNA damage and the OxyR response induced by oxidative stress (e.g., hydroxyl radicals). In the present study, we have investigated interactions between these two systems under the assumption that harmful conditions may generally induce more than one bacterial response, and in such a case, their combined effect might feature additional factors critical for survival. We used IMPORTANCE: Many microorganisms such as pathogenic bacteria that attempt to invade a host will encounter a series of host-produced challenges that try to thwart their entry into and establishment within the host. As a countermeasure, the invading organisms have evolutionarily developed a range of stress responses that will help them to counter such challenges. The current study explores what happens in the bacterium