Fig 4. Microscopic observation of biofilms treated with high concentrations of polypyrrole.

GtfBC mutant was incubated with 0 (control), 8, 16, 32 and 63 x 10 μg/ml polypyrrole and stained without (A) or with (B) a Gram staining kit. The aggregates were observed by microscopy. Squares were presented as an enlarged view. Representative data from more than three independent experiments were presented in the images.