Figure 2.

PQS production by P. aeruginosa. (a) PQS produced by wild-type PAO-1 Lo and a PQS-null mutant (PQS−) grown in N-minimal medium containing either 8 μM or 1 mM Mg²⁺. PQS is indicated by the arrow. (b) PQS production by P. aeruginosa isolates from five infants with CF and non-CF isolates from blood or urinary tract infection (UTI) grown in rich medium (TSB). (c) PQS production during growth in TSB by two laboratory P. aeruginosa strains (PAO-1 Ig and PAO-1 Lo) and isolates from four patients with CF. Absorbance of bacterial culture at 600 nm (OD) at which PQS was extracted is indicated. All strains had similar growth rates. Bacteria remained in logarithmic growth phase until OD 4.0, doubling every 120 min. (d) PQS production by sequential clonal P. aeruginosa isolates from a patient with CF grown in TSB. The patient's age in months (mo) is indicated.