Fig. 6.

Production of NO and N₂O from NO₂⁻ by wild-type and mutant strains of M. catarrhalis O35E. Cell suspensions of the wild-type strain (A), the norB mutant (B), the aniA norB mutant (C), and the aniA norB mutant (D) in BHI medium supplemented with 500 μM NaNO₂ were monitored for 15 min for the presence of NO· (blue lines) using an NO· -specific electrode. Probe specificity was affirmed by the ability of an NO· scavenger, Carboxy-PTIO, to quench measurable signal (not shown). The presence of N₂O (green lines) was measured simultaneously using an oxygen-insensitive, N₂O-specific probe as described in Materials and Methods. The data shown are a representative set of results from two independent experiments.