Fig 6. Dispersal of mature biofilms of [P.] pneumotropica biotypes Jawetz (A) and Heyl (B) by DNase I.

The supernatants of 24 h old biofilms of the strains indicated along the x-axis were replaced for 2 h by buffer alone (black bars) or buffer containing 50 μg/ml DNase I (grey bars). Biofilm quantity was then recorded using a standard crystal violet assay by measuring the absorbance at 540 nm. Bars represent mean values + standard deviation of at least three independent experiments. Asterisks (*) designate a p-value less than 0.05 between the treated group and the corresponding control.