Fig 3. The addition of tryptophan to a stationary phase BW25113 culture leads to further indole synthesis.

Stationary phase (24 hours) BW25113 cells were incubated with no additional tryptophan or 2 mM tryptophan added every subsequent 24 hours (arrows indicate times of addition). Samples were removed then centrifuged to remove cells. The supernatant was assayed for external indole using Kovacs assay. Data shown are the mean values ± standard deviation for three independent repeats.