Fig 3. Characterization of ΔsdbA biofilms.

(a) Alcian blue binding assay for surface charge in cells grown to early stationary phase in HTVG medium (Inoculum), and (b) in cells grown in 24 h biofilms (Biofilm). Bars represent the percentage of unbound dye. (c) Total carbohydrate production. (d) Sensitivity to DNase I and trypsin. Biofilms were grown for 24 h prior to the addition of either DNase I or trypsin, and incubated for an additional 1 h before staining with crystal violet. Data were analyzed by one-way ANOVA and asterisks indicate a significant difference from the control biofilm for each strain (***P ≤ 0.001**P < 0.01, *P < 0.05).