FIG. 5.
Effect of relA overexpression on the production of 3-oxo-C12-HSL and C4-HSL. The concentrations of autoinducers were determined in bacterial supernatants of either strain PAO1(pMMB67) (squares) or PAO1(pMRL4) (diamonds). Overnight cell cultures were washed and resuspended in LB medium at an initial turbidity at 600 nm of 0.05. Supernatants were collected at regular intervals, extracted with ethyl acetate, and assayed for the presence of both autoinducer molecules using specific bioassays as described in Materials and Methods. Shown are the means (± SDs) of results from three independent experiments performed in triplicate. (A) Bioassay for 3-oxo-C12-HSL. (B) Bioassay for C4-HSL.