Derepression of the alternative cytochrome <i>bd</i> oxidase contributes to Zn(II) resistance.

<p>(A and B) Susceptibility of WT and mutant strains to Zn(II) as assessed by disk diffusion assay. The data are expressed as the diameter of the zone of inhibition (ZOI) as measured in millimeters. The mean and standard error of three independent experiments is shown. Asterisks indicate significance as determined by a Student’s <i>t</i>-test (P<0.05). (C) Model of the contribution of the Rex regulon to Zn(II) resistance.