Figure 1.

Elevated NO^• consumption by NO^•-resistant mutants of E. coli. (A) Cultures were grown in phosphate-buffered LB medium with minimal aeration (open bars), with vigorous shaking under air (hatched bars), or under an atmosphere containing 960 ppm NO^• in 21% O₂ balanced with N₂ for 60 min (filled bars), and cells were harvested and washed and NO^• consumption was measured. (B) A total of 2.5 million cells from logarithmic cultures of AB1157, PG110, and PG118 were plated on phosphate-buffered LB agar medium containing phanazine methosulfate (50 μM) and were exposed to 960 ppm NO^• under an atmosphere of 10% air balanced with N₂ or to air at 37°C for 16 h. Cultures were then incubated at 37°C under a normal air atmosphere for 24 h to allow the outgrowth of bacterial colonies. Colonies were counted and percent survival was calculated relative to air exposed controls (n = 2; ±SD).