Fig 4.

Addition of tryptophan causes disassembly of existing P. aeruginosa biofilms. P. aeruginosa biofilms were allowed to form in wells with M63 medium incubated at 30°C for 48 (A) or 72 h (B). The medium was removed, fresh medium with the indicated amounts of d-/l-tryptophan (0.0 to 10.0 mM) was added, and the plate was incubated for an additional 24 h at 30°C. Biofilm formation (crystal violet stain) was evaluated for the initial biofilm and after 24 h of incubation with or without tryptophan. *, P < 0.05 compared to the initial biofilm.