Figure 7.

Analysis of the activation of promoters involved in QSSMs synthesis. Time-course of (A) PlasI, (B) PrhlI, and (C) PpqsA expression was analyzed in PAO1, ΔmexL, and ΔmexK strains growing in LB medium for 20 h, using a chromosomal insertion of the reporter construction of each promoter followed by the operon luxCDABE. The total area under the curve was quantified and is represented. As shown, luminesce driven by the pqsA promoter was strongly impaired in the strain that overproduces the MexJK efflux system. Values that are significantly different with respect to those obtained in the PAO1 strain by an unpaired two-tail t-test are indicated by asterisks as follows: * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001.