Figure 2.

Phenotypic characterization of hrpB mutant in P. aeruginosa PAO1. (A) Growth properties of wild-type PAO1 (solid symbols) and ΔhrpB mutant (empty symbols) in LB medium at 43°C (triangles), 37°C (circles) and 25°C (diamonds). (B) Survival assays of wild-type PAO1 and ΔhrpB mutant to cold shock (16°C), oxidative stress (2 mM H₂O₂) and osmotic stress (0.5 M NaCl) as compared to 37°C growth. (C) Surface area covered by the swimming, swarming, and twitching cells (±standard deviation) of wild-type PAO1 or ΔhrpB mutant as calculated by averaging data from four individual plates. (D) Biofilm formation of wild-type PAO1 or ΔhrpB mutant measured by crystal violet staining or by Congo-red staining. (E) Survival curves of G. mellonella larvae infected with wild-type PAO1, ΔhrpB or hfq- mutant. PBS, larvae injected with sterile physiological solution. Each experiment (A-D) was repeated at least with three different independent cultures for each strain, values indicated average from biological replicates ± standard deviation. For experimental details see Material and Methods.