Figure 4
CA439 inhibitory effect on PmrA/PmrB activity depends on PhoP/PhoQ. (a) Transcriptional activity from arn::gfp (left) or pmrCAB::gfp (right) fusions in the wild type strain grown in the presence of 100 μM FeCl3, 5 mM MgCl2 or 25 μM CA439. (b) Transcriptional activity from pmrCAB::gfp fusion in a phoP (left) or phoPQ (right) mutant strain background grown in the presence of increasing concentrations of FeCl3 (25, 50, 75, 100 μM) with or without the addition of 25 μM CA439. Bacteria were grown at 37 °C for 16 h in the condition indicated in each assay. Transcriptional activity was calculated from the ratio between the fluorescence values (FU) and OD600 values (FU/OD600). The results represent the average of at least three independent experiments and error bars correspond to standard deviation (SD). Statistical analysis was performed using a, one-way ANOVA with Tukey’s correction multiple comparison test (****P < 0.0001, ***P < 0.001, **P < 0.01) or (b) unpaired t test (ns, no significant differences).
