Role of ArcA in modulating the redox status in aerobiosis and in response to H
. Strains 14028s and ΔarcA were grown to OD600 ~ 0.4 and treated with 1.0 mM H2O2 for 20 min. Control cells received no treatment. The levels of (A) glutathione reductase (GR) activity, (B) reduced glutathione (GSH), oxidized glutathione (GSSG), (C) the GSH/GSSG ratio and (D) the NADH/NAD+ ratio were measured. (E) Total ROS amount was measured under aerobic conditions. Values are the mean ± SD of three independent experiments. Values were normalized by protein concentration (A, B, C, D) or OD600(E). AU: arbitrary units. GR activity: nmol NADPH min-1 ml-1 mg protein-1. *p ≤ 0.05, **p ≤ 0.01, as compared to aerobically grown wild type cells.