FIGURE 4.

Nitric oxide production capacity (A) and N₂O accumulation (B) by R. etli narB, narB + NarB⁺, nirK, and norC mutants. In (A) cells incubated microoxically with NO₃⁻ were transferred to a reaction chamber with NO₂⁻. In (B) cells were cultured microoxically with NO₃⁻ or NO₂⁻ as the sole N-source. Data are expressed as the mean value and error bars from two different cultures assayed in triplicate.