Fig 2.

Effect of d-/l-tryptophan on growth of P. aeruginosa and biofilms. (A) Bacterial growth in M63 media with the indicated concentrations of tryptophan was assessed by measuring absorbance at 595 nm. Significant reductions (P < 0.05) were observed at 40 to 60 h for the 5.0 mM treatment group and at 32 to 72 h for the 10.0 mM treatment group. (B) Reduction in CFU/ml was also observed with 5.0 mM tryptophan at 48 to 60 h and with 10.0 mM tryptophan at 48 to 72 h (P < 0.05). (C) Dose-dependent inhibition of biofilm formation (crystal violet stain). Each data point is plotted as the mean ± standard error of 3 independent experiments.