Figure 1.

Lucigenin luminescence elicited by sodA sodB (JI132) and parental (AB1157) E. coli as a function of carbon source. Overnight cultures were diluted 40-fold with fresh LB and were grown for 90 min, at which point A₆₀₀ was 0.25 for JI132 and 1.0 for AB1157. Cells were collected, washed in 50 mM sodium phosphate (pH 7.3), and resuspended in this buffer, or in LB medium at pH 7.0, to equal densities. Reaction mixtures contained 0.72 ml of medium, 40 μl of cell suspension, and 40 μl of 2.0 mM Luc⁺⁺. Luc⁺⁺ was the last component added. A₆₀₀ in the reaction mixture was 0.5. Luminescence yield from five sequential 10-sec integration times, separated by 5-sec delay times, were averaged. Bars 1 and 2 represent JI132 and AB1157, respectively, both in 50 mM sodium phosphate (pH 7.3) plus 0.25% glucose. Bars 3 and 4 represent JI132 and AB1157, respectively, both in LB medium. Bars 5 and 6 represent JI132 and AB1157, respectively, both in 50 mM sodium phosphate (pH 7.3) plus 0.25% succinate.