Fig. 7
From: BrlR from Pseudomonas aeruginosa is a receptor for both cyclic di-GMP and pyocyanin
The correlation between pyocyanin and c-di-GMP in regulation of BrlR. a Elevated pyocyanin and decreased c-di-GMP levels render the planktonic P. aeruginosa PAO1 cells, but not ΔbrlR cells, resistant to tobramycin. All strains were grown planktonically to the mid-log phase in the presence or absence of 0.2 mM pyocyanin, which was purified from stationary phase cultures of PAO1. Susceptibility of P. aeruginosa strains was determined by the treatment of 50 μg/ml tobramycin for 1 h. Strain PAO1 harboring the empty plasmid pHERD20T was established as a control, and strain PAO1 or ΔbrlR containing pHERD20T-PA2133 was shown to contain a low level of c-di-GMP5. Error bars, s.d., obtained from triplicate experiments. The data were analyzed with a one-tailed t-test (***P ≤ 0.001). b c-di-GMP and pyocyanin can cooperatively enhance BrlR-DNA binding. EMSA for the interaction between FAM-labeled PbrlR DNA and BrlR in the presence of c-di-GMP, pyocyanin, and both. The concentration of each component is indicated. The BrlR-DNA complexes were quantified by band densitometry (right). Error bars, s.d., obtained from triplicate experiments
