Fig. 4.

The kynurenine pathway genes are not induced by kynurenine in a kynR mutant. β-Gal activity of kynA′-lacZ fusion (pJF03) (A) and (B) kynB′-lacZ fusion (pJF01) (B) in strains PAO1 (solid bars), PAΔKynR (striped bars), PAO-R1 (open bars), and PAO-R1ΔKynR (stippled bars) were assayed in cultures grown in VBG for 6 h and then supplemented with either water (as a control) or 1 mM l-kynurenine for 18 h. β-Gal activity is presented in Miller units as the mean ± σ^{(n − 1)} of results from duplicate assays from at least three separate experiments.