Oxidative stress.

Much has been learnt about oxidative stress from studies of Escherichia coli. Key regulators of the adaptive responses in this organism are the SoxRS and OxyR transcription factors, which induce the expression of antioxidant activities in response to O2*- and H2O2 stress, respectively. Recently, a variety of biochemical assays together with the characterization of strains carrying mutations affecting the antioxidant activities and the regulators have given general insights into the sources of oxidative stress, the damage caused by oxidative stress, defenses against the oxidative stress, and the mechanisms by which the stress is perceived. These studies have also shown that the oxidative stress responses are intimately coupled to other regulatory networks in the cell.