FIG 4.

P. aeruginosa dispersion is dependent on quinolone biosynthesis. Biofilms were grown in semibatch cultures in 24-well plates, and the fraction of microcolonies that had dispersed was determined. (A) PA14 wild type and pqsA mutant biofilms were assessed for dispersion after 4, 5, 6, and 7 days of growth. (B) Dispersion of the pqsA mutant overexpressing the pqsA gene was assessed after 6 days of growth and compared to that of the wild type and pqsA mutant. Representative images show microcolonies in PA14 wild-type (C), PA14 ΔpqsA (D), and PA14 ΔpqsA/pJN105-pqsA (E) biofilms after 6 days of growth. Central voids are clearly visible in panels C and E. Error bars represent the standard deviations calculated from at least three biological replicates. Scale bars, 100 μm. Statistical significance was determined using Student’s two-tailed t test for panel A and one-way ANOVA followed by Tukey’s post hoc test for panel B. n.s., P > 0.5; *, P < 0.05; **, P < 0.01.