Figure 6

Relative siderophore production by wild-type MR-1 and Δ so2426 mutant cells under chromate conditions. A final chromate concentration of 0.3 mM was added to mid-log-phase (OD₆₀₀, 0.5) wild-type MR-1 (●) and Δso2426 mutant (○) cultures cultivated in LB broth, and relative siderophore synthesis by each culture was monitored over time using the CAS assay. The relative siderophore production was calculated by subtracting the supernatant A₆₃₀ for the wild type or mutant from the uninoculated control and then determining the ratio of corrected supernatant A₆₃₀ to control A₆₃₀. The graphed values represent mean ratios ± standard errors (bars) for three replicate CAS measurements.