FIG. 2.

nirS (A), cnorB (B), and nosZ (C) gene expression in P. mandelii grown in TSB medium supplemented with 0 mg (♦), 10 mg (▪),100 mg (⋄), or 1,000 mg (□) of KNO₃/liter. Error bars are ± 1 SEM (n = 6 for cnorB and nirS and n = 3 for nosZ). Values were calculated from the line of best fit described by the linear equation for cnorB: y = −4.112x + 46.661 (r² = 0.99) for the first experiment and y = −4.800x + 53.412 (r² = 0.99) for the second experiment. For nirS, y = −2.883x + 45.326 (r² = 0.99) for the first experiment and y = −2.377x + 42.393 (r² = 0.86) for the second experiment. For nosZ, y = −4.414x + 46.328 (r² = 0.99).