Fig 1.

dksA mutant Salmonella strains are hypersusceptible to the bacteriostatic activity of NO. (A) The concentrations of NO released by 5 mM DETA NONOate (dNO) in LB broth incubated with 2 × 10⁷ CFU/ml of Salmonella Typhimurium strain 14028s were measured polarographically over time at 37°C in a shaker incubator. Data from two independent observations are expressed as means ± standard deviations (SD). (B and C) Wild-type (WT) and the isogenic ΔdksA Salmonella strain AV09294 grown overnight in LB broth were diluted to 2 × 10⁷ CFU/ml in fresh LB broth and treated with 5 mM polyamine DETA (control) (B) or dNO (C). (D and E) Selected control (D) and dNO-treated (E) cultures were supplemented with 0.1% Casamino Acids (AA). Bacterial growth is expressed as the OD₆₀₀ over time, and the data are represented as the means of 10 independent observations from 2 separate experiments. The P value for the difference between the ΔdksA and wild-type strains was <0.0001 as determined by one-way ANOVA of all data points in the curve followed by Bonferroni's posttest.