Fig. 6.

Acidification of pHi provides advantage in NO resistance of E. coli strains. To modulate pHi to pH 7.1 and pH 7.6, the LB media were prepared in 50 mM HEPES buffer with the indicated pH values containing 100 μM monensin and 10 μM nigericin. When necessary, 5 mM DETA NONOate (a long-acting NO donor) was added at the points indicated by arrows. Cell viability assay was performed by monitoring the optical density at 600 nm (A₆₀₀ nm). Standard deviations were calculated from three independent biological replicates.