FIGURE 2.

Malate utilization represses alternative carbon sources of arginine catabolism and fatty acid β-oxidation, which is partially mediated by CRP. The relative expression of genes encoding various amino acid transporters were compared in WT strain under malate present (WT + M) and absent (WT-M) conditions (A), and between WT and Δcrp strains with malate supplementation (WT + M; Δcrp + M) (B). Each dot is representative of a single gene. The dashed lines represent a twofold over-expression (black, upper line), equal-expression (red, middle line) and –2-fold expression (black, lower line) of ratio of axis Y/X defined by log₂ of FPKM. (C) Comparison of the transcriptional profiles encoding arc operons and fatty acid β-oxidation in WT and Δcrp, aerobically cultured in modified minimal medium M63 with (WT + M; Δcrp + M) or without malate addition (WT-M); as well as in WT and Δfnr, aerobically (WT_AE) and/or anaerobically (WT_ AN; Δfnr_AN) cultured in Lytic/10 Anaerobic/F Medium. (D) Under the above conditions (C), the transcript levels of two randomly selected genes that encode for arginine catabolism were determined by qRT-PCR. Error bars represent means ± SEM of three independent experiments (^∗P < 0.05; ^∗∗P < 0.01; ^∗∗∗P < 0.001).