FIG 3.

Biofilm formation of B. subtilis. (A) Colony of B. subtilis on agar surface. (B) B. subtilis biofilm surfaces are highly hydrophobic. A drop of colored water (5 μL) is placed on top of the colony. (C) Scanning electron microscopy of a B. subtilis biofilm. Note the evenly covered surface of the biofilm, which occurs because of the hydrophobic protein BslA. (D) Transmission electron microscopy image of a thin section through a B. subtilis biofilm. Cells at the bottom of the biofilm tend to lyse and appear lighter. Scale bars are 0.5 cm (A) and 10 μm (C and D).