FIG 3.

Cells of the ΔoxyR strain on LB plates die quickly. Experiments were performed at least three times, and similar results were obtained. (A) Effects of catalase on the plating defect of indicated strains on LB plates. Cultures were serially diluted, and the indicated dilution of each strain was dropped on LB plates. Catalase (2,000 U) was applied to the drops at the indicated times. Production of AhpCF and KatB at various levels was induced by IPTG. (B) Catalase staining analysis. Cells were collected just before and 30 min after the addition of 0.2 mM H₂O₂. Proteins from the indicated cell lysates were separated by native PAGE and stained for catalase activity. Overproduction of KatB induced by 0.2 mM IPTG resulted in KatB aggregates, forming the supercomplex.