Fig. 5.

Biofilm formation by wild-type (WT) and yidC mutant strains. Biofilms were allowed to develop for up to 48 h (pH 7.0) or 36 h (pH 5.0) in THYE 0.5 % sucrose using hexidium iodide-labelled mid-exponential-phase cultures at the pH conditions indicated. Two areas from each biofilm that formed on the cover glass were visualized and the thicknesses of three sections through each area were measured. Representative images of overhead and side views of biofilms made by each strain are shown. The measured thickness values of biofilm (in µm; mean±sd) of three cross-sections from each of two fields per well performed for duplicate wells are given on the figure. For WT, ΔYidC1 and ΔYidC2 at pH 7.0 after development for 24 h the values were 7.33±0.50, 8.75±0.89* and 6.14±0.71*, respectively (significance given below). Each experiment was performed twice. Statistically significant differences compared with the wild-type are indicated. *P≤0.001. ND, not determined, growth was too patchy to accurately measure thickness.