FIG. 8.

Analysis of wild-type and zwf mutant cell extracts for paraquat:NADPH and paraquat:NADH oxidoreductase activity. P. aeruginosa PAO1 and PAO9010 containing either pEX30 (vector control) or the zwf expression vector pJFM3 were grown in L broth minus NaCl containing 400 μg of carbenicillin per ml and 0.2 mM IPTG until mid-logarithmic phase (OD₆₀₀ = 0.6), and the culture was divided into two parts. One set was treated with 100 μM paraquat (PQ), and the other served as a control. These suspensions were incubated aerobically for an additional hour at 37°C prior to preparation of cell extracts. Extracts were separated by nondenaturing PAGE on 7.5% polyacrylamide gels and stained for paraquat:NADPH (A) and paraquat:NADH (B) oxidoreductase activities as previously described (40). Lanes 1 through 4, mid-logarithmic-phase organisms; lanes 5 through 8, mid-logarithmic-phase organisms plus 100 μM paraquat for 1 h. Lanes 1 and 5, PAO1(pEX30); lanes 2 and 6, PAO1(pJFM3); lanes 3 and 7, PAO1 zwf(pEX30); lanes 4 and 8, PAO1 zwf(pJFM3).