FIG. 5.

(A) Effects of various inorganic nitrogen sources on the RDX degradation activity (closed symbols) and growth (open symbols) of KTR9. A 4 mM concentration of (NH₄)₂SO₄ (triangles), KNO₃ (squares), or KNO₂ (diamonds) was included as a competing nitrogen source compared to RDX alone (circles). Error bars are the standard errors of three samples. (B) Quantitative real-time PCR expression analysis using primers for xplR, cyp151C, glnA-xplB, xplA, and a 16S rRNA. RNA was harvested from KTR9 cells grown for 24 h on media containing the indicated nitrogen sources: RDX alone (diagonally striped bars), RDX plus (NH₄)₂SO₄ (white bars), RDX plus KNO₂ (black bars), and RDX plus KNO₃ (horizontally striped bars). Relative expression of gene targets was normalized to corresponding gene expression levels for cultures in which RDX was the sole nitrogen source.