FIGURE 1.

Sodium nitrate and sodium nitrite, but not sodium chloride, inhibit biofilm formation in Burkholderia pseudomallei 1026b. (A) Biofilm inhibition was assessed for static biofilm cultures growing at 37°C in the presence of sodium chloride, sodium nitrate, or sodium nitrite at 1, 2, 3, 5, 8, 10, 20, 50, and 100 mM. All experiments were performed with wild-type B. pseudomallei 1026b and inhibition was evaluated relative to wild-type biofilm formation in LB without additional salts added. Asterisks indicate a significant difference (^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001) calculated with an unpaired Student’s t-test using the Holm-Sidak method to account for multiple comparisons (n = 12). Growth curves were generated from cultures grown with shaking at 37°C in the presence of either sodium chloride (B) or sodium nitrate (C) using concentrations as indicated for the biofilm inhibition assay. Absorbance (OD₆₀₀) measurements were taken hourly for 30 continuous hours.