Fig. 3.

Nitrite represses mycobacterial growth. (A and B) Strains of Mtb designated as in Fig. 1 (OD₅₈₀ 0.1, as marked by horizontal dotted lines) were incubated in the presence of the indicated concentrations of nitrite (A) or nitrate (B) for 3 d in 1% oxygen and then transferred to 21% oxygen for 5 d before growth was assessed by measuring OD₅₈₀. Means ± SD, n = 2 experiments. (C) As in A and B, except that cfus were determined at the end of the 3-d incubation in 1% oxygen for WT Mtb. Means ± SD, n = 2 experiments.