Figure 8. Effect of Proteinase K on biofilms and measurement of extracellular protease activity in AIP-detached biofilms.

(A) Proteinase K (proK, 2 µg/ml) was added to a 2 day old biofilm (strain AH500) and the biofilm integrity was monitored with CLSM at 6 and 12 hr. (B) Levels of protease activity detected in biofilm effluent collected from wild type (SH1000) or Δagr (SH1001) biofilms supplemented with indicated AIP's. Protease activity was referenced to wild-type without AIP addition. (C) The effect of inhibitors or activators on the proteolytic activity in an AIP-I detached biofilm effluent. Activity assay was supplemented with either the metalloprotease inhibitor EGTA (1 mM), serine protease inhibitor PMSF (10 µM), or the reducing agent DTT (1 mM). Error bars show SEM.