FIG 4.
Relative expression of iutA, iutE, and iutD. Relative transcript levels for iutA (A), iutE (B), and iutD (C) were determined in the C. diphtheriae 1737 wild-type (wt) strain and isogenic ΔdtxR and Δzur mutants. Relative expression was determined using the ΔΔCq method comparing against the respective wild-type transcript levels following low-iron growth (wt 0.5 Fe set to 1); statistical significance was determined by two-way ANOVA and multiple-comparison test on ΔCq values. *, P < 0.05; **, P < 0.01 (when comparing the indicated sample against the wt 0.5 Fe sample; n = 3). n.s., not significant. Final concentrations of metals (micromolar) are indicated.