Changing of expression of antioxidant genes in Escherichia coli during growth on various sources of carbon and energy

In bacteria various stresses are accompanied by an increased production of reactive oxygen species (ROS). Consequently, the level of expression of antioxidant genes may play an important role in bacterial adaptation to changing environments. In this paper, using aerobically growing cultures of Escherichia coli, we have evaluated the effect of carbon and energy sources on expression of antioxidant genes katG, katE and sodA, coding, respectively, catalases HPI, HPII and Mn-superoxide dismutase. When grown on succinate, malate, а-ketoglutarate or acetate as a sole source of carbon and energy, katG gene expression was, respectively, 1.5, 1.6, 1.7 and 2.3 times higher than during growth on glucose. Expression of the katE gene during growth on succinate, malate, а-ketoglutarate or acetate was higher than that during growth on glucose, in 1.8, 1.95, 1.5 and 2.1 times, respectively. Expression of the sodA gene decreased during the periodic growth on glucose, succinate and malate. Under growth on acetate, sodA expression maintained constant and 1.2 - 1.8 times exceeded the level on glucose. The rate of superoxide production and the level of H2O2 in the medium decreased under conditions, which promoted enhanced expression of antioxidant genes.