FIG 2 .

Role of the NorR regulon in NO resistance in vitro. To test the effect of NO on the growth of mutant strains, bacteria were inoculated in triplicate into a sealed 96-well plate in minimal medium at 37°C in the absence (A) or presence (B) of 10 µM DETA-NONOate. Growth was measured by determining the OD₆₀₀ every 10 min. The strains used were as follows: black, wild type (WT); blue, ΔhmpA mutant; green, ΔnnrS mutant; red, ΔnorR mutant; purple, ΔhmpA ΔnnrS double mutant. Error bars indicate standard deviations.