Colony morphology and AQ production of various QS mutants. A. Colony morphology of the ZK wild-type (WT), lasR, pqsH, lasR pqsH double mutant, and lasR pqsA::Tn suppressor mutant after 5 days at 37°C. B. TLC analysis of AQ production by the respective strains. Approximately 5 μl of each sample (normalized to total amount of protein) was loaded. Note that samples towards the center of the plate ran more slowly than those near the edges. HHQ and PQS, representing Series A and B congeners, respectively, were included as synthetic controls. C. Densitometric analysis of TLC spot intensities in the wild-type and the lasR mutant from two independent experiments.