FIG 1 .

Effects of NO and NorR on the expression of NO detoxification genes. Strains containing a promoter-lacZ reporter were grown in minimal medium under microaerobic conditions. hmpA (A), nnrS (B), or norR (C) promoter activity was measured after the addition of a 50 µM concentration of the control compound diethylamine (white bars) or the NO donor DEA-NONOate (gray bars) and is reported in Miller units (34). Experiments were performed with wild-type (WT) strain C6706 or a strain containing a clean deletion of the entire norR open reading frame. Error bars represent standard deviations. *, P < 0.05; ***, P < 0.001 (for experiments performed in triplicate).