Validation of the microarray data by Real Time PCR.

Relative mRNA levels of the genes indicated quantified by Real Time PCR in the P. aeruginosa ∆4AQ strain grown in LB supplemented with 1 mM IPTG to induce PqsE expression (light-grey bars), or with 40 μM PQS (white bars), HHQ (dark-grey bars), or HQNO (black bars), with respect to the same strain grown in LB. The average of two independent analyses each performed on three technical replicates is shown with standard deviations.