FIG 6 .

Mucoid clinical isolates display differing levels of production and dependence on Psl. (A) Psl was isolated from stationary-phase cultures and quantified by immunoblotting. Three biological replicates were performed in triplicate. The average Psl concentration is depicted. Statistical significance was determined by a one-way ANOVA, followed by Dunnett’s multiple-comparison test (**, P ≤ 0.01; ***, P ≤ 0.001). Each mutant was compared to the mucoid Ppsl mutant PDO310. The dotted line depicts double the amount of Psl produced by strain PDO310 for reference. (B) Peg biofilm assays were performed to determine the biofilm-forming potential of mucoid clinical isolates. Biofilms were grown for 4 h, followed by a 1-h treatment with PBS (gray bars) or 86 nM PslG glycosyl hydrolase. Crystal violet staining revealed adherent biomass after treatment. Three biological replicates were treated in triplicate. Statistical significance was determined by a two-way ANOVA, followed by Bonferroni’s posthoc test to compare untreated to PslG-treated samples (*, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001).