FIG 1.
P. aeruginosa inoculated into expectorated CF sputum from different donors exhibits a zinc starvation response. (A) P. aeruginosa strain PAO1 PrpmJ2-lacZ was grown in LB (Control), LB with 50 μM TPEN (TPEN), or LB with 50 μM TPEN and 1 mM ZnSO4 · 7 H2O (TPEN+Zn) for 3 h. The data shown represent the mean ± standard deviation (SD) from three independent experiments. (B) P. aeruginosa strain PAO1 PrpmJ2-lacZ was grown in M63 (Control), M63 with 50 μM TPEN (TPEN), or expectorated CF sputum (Sputum) for 3 h. Each point in the sputum set indicates a separate sample from a different donor. The data were analyzed by Brown-Forsythe and Welch ANOVA with Dunnett’s T3 multiple-comparison test. (C) P. aeruginosa strain PAO1 was inoculated into M63 (M63) or into sputum from two different donors (Sputum 1 and Sputum 2). The sputum was divided and left untreated (Sputum), treated with 1 mM ZnSO4 · 7 H2O (Sputum+Zn), or treated with 1 mM (NH4)2Fe(SO4)2 · 6 H2O (Sputum+Fe). Each condition was analyzed in triplicate. Expression of select Zur-regulated genes was measured by NanoString (codeset PAV4). Expression values are normalized to the geometric mean of loading controls and Z-score was scaled by gene. The data in panel A and panel C were analyzed by one-way ANOVA with Tukey’s multiple-comparison test. Samples marked with the same letter are not significantly different; samples marked with different letters are significantly different (P < 0.05). *, P < 0.05, **, P < 0.01.