Figure 3
From: The serine protease HtrA plays a key role in heat-induced dispersal of pneumococcal biofilms
Role of protease activity in heat-induced biofilm dispersal. (a) D39 and (b) EF10175 biofilms were exposed to protease inhibitors PMSF (20 μM), leupeptin (10 μM), or E-64 (10 μM) at 34 °C or 38.5 °C for 4 h. Supernatants containing the released bacteria were enumerated by viable plate counts. The relative bacterial release is shown as a ratio of the CFU/ml at 38.5 °C compared to 34 °C and then normalized to the control without inhibitor. For reference, the average bacterial release for the control was approximately 6.5 × 107 CFU/ml for D39 and 9.7 × 107 CFU/ml for EF10175, which was 3.6 times or 2.8 times higher than the release at 34 °C, respectively. Data represent triplicates from four separate experiments, with the mean and SEM displayed. Statistical analysis was performed using Mann–Whitney U test by comparing to the control; *P < 0.05.
