Plating defect of the oxyR mutant is not caused by iron starvation. Effects of indicated metal ions (Fe2+, FeSO4; Mn2+, MnCl2; Zn2+, ZnSO4; Mg2+, MgCl2; K+, KCl; and Fe3+, FeCl3) on the plating defect of indicated strains on LB plates. For each metal ion, five different concentrations (2× increases) were tested, and the results for the concentrations that had the most significant effect are shown.