FIG 4.

Clotrimazole, clofoctol, and miconazole inhibit PqsR functionality. (A) Real-time RT-PCR analysis showing the mRNA level of pqsR in PAO1 cultures treated with 100 μM concentrations of the indicated drugs relative to untreated PAO1 cultures. The PAO1 ΔpqsR strain was used as a negative control. The average from three independent experiments is reported, along with the SD. ns, nonsignificant difference; ***, P < 0.001 (ANOVA). (B) Western immunoblotting performed with anti-6×His antibody on crude protein extracts of PAO1 ΔpqsAHR(pPqsR-6H) grown in LB supplemented with 10 μM PQS and 20 μM IPTG, in the absence (untreated) or in the presence of the indicated drugs (100 μM). The PAO1 ΔpqsAHR strain carrying the empty vector pME6032 was used as a control. The data are representative of three independent experiments. (C) Effect of 100 μM clotrimazole (white bars), clofoctol (light gray bars), and miconazole (dark gray bars) on PpqsA::lux activity in the PAO1 ΔpqsA ΔpqsH ΔpqsR mutant carrying the pPqsR-6H plasmid, grown in LB supplemented with 10 μM PQS and different concentrations of IPTG as indicated in the graph. The averages from three independent experiments are reported, along with the SD.