Enhanced OMV production by the oprF mutant, but not the oprI mutant, is due to increased PQS production. (A) Representative growth curves of wt P. aeruginosa (PA14), the oprI pqsH double mutant, the oprF pqsH double mutant, and the pqsH mutant (pqsH) grown with shaking (250 rpm) at 37°C in BHI. (B) OMV production by wt P. aeruginosa, the oprF mutant, the oprF pqsH double mutant, the oprI mutant, the oprI pqsH double mutant, and the pqsH mutant. The majority of samples from strains lacking pqsH did not produce detectable amounts of OMVs. (C) OMV production upon addition of increasing levels of PQS. Synthetic PQS was added exogenously to cultures to a final concentration of 0.5, 10, 20, or 40 μM, and OMV levels were quantified. All cultures were grown with shaking (250 rpm) at 37°C to an OD600 of ∼3.5, and OMVs were quantified using the lipid assay. *, P ≤ 0.01 compared to wild type (B) or the pqsH mutant (C) via two-tailed Student's t test, assuming equal variance (n ≥ 3).