Fig. 2.

dspB mediates dispersal in response to H₂O₂. (A) Quantitative microtiter dish assay for measuring biofilm dispersal. (1) Aa is incubated statically under anoxic conditions to promote attachment to the bottom of microtiter dish wells, (2) biofilms are incubated under oxic shaking conditions either with (+H₂O₂) or without H₂O₂ addition, and (3) biofilm mass is quantified using crystal violet. (B) Crystal violet incorporated into biofilms was solubilized and quantified by measuring absorbance. The y axis represents the absorbance reading for H₂O₂-treated biofilms divided by the reading for untreated biofilms. A value less than one thus indicates that dispersal occurred, whereas a value close to one indicates that dispersal was absent. Error bars represent SEM (n = 4). *P < 0.015 by a two-tailed Student t test.