Identification of a General O-linked Protein Glycosylation System in Acinetobacter baumannii and Its Role in Virulence and Biofilm Formation
Figure 5
A. baumannii requires PglLAb for biofilm formation.
A) Quantitative biofilm formation on polystyrene 96 well plates by strains incubated without perturbation in LB at 30°C. The bars indicate the means for 8 replicates. The error bars indicate the standard deviation of the means. Asterisks indicate significant differences (*, P<0.005 [t test; n = 8]; **, P<0.001 [t test; n = 8]). B) The median surface coverage after incubation for 2 h in flow cell chambers of the WT, ΔpglL, ΔpglL pWH1266 and ΔpglL ppglL was determined by the COMSTAT software. For each strain at least six micrographs from three independent experiments were analyzed. The error bars indicate the interquartile range. Asterisks indicate significant differences (*, P<0.05 [Mann-Whitney U test; n = 6]). C)–E) Image stacks of the WT, ΔpglL, ΔpglL pWH1266 and ΔpglL ppglL biofilms grown in flow cells for 24 h were analyzed for the biomass as well as the maximum and average thickness using the COMSTAT software. Shown are the medians of at least six image stacks from three independent experiments for each strain. The error bars indicate the interquartile range. Asterisks indicate significant differences (*, P<0.05 [Mann-Whitney U test; n = 6]). F) Shown are representative confocal laser scanning microscopy images of the WT (upper row) and ΔpglL mutant (lower row) biofilms grown in flow cells for 24 h. The first three images represent horizontal (xy, large panel) and vertical (xz and yz, side panels) projections at different z-levels (from left to right 0.2 µm, 3 µm and 6 µm). The fourth micrograph of each row represents a three-dimensional image analyzed by the AMIRA software package of the WT and ΔpglL mutant biofilms, respectively.