FIG 4.

Citrulline does not complement C. burnetii growth in ACCM-D lacking arginine. (A) Schematic of the arginine biosynthesis pathway. L. pneumophila contains argDEFGH with argG (lpg0494, argininosuccinate synthase), argH (lpg0495, argininosuccinate lyase), and argF (lpg0496, ornithine carbamoyltransferase) arranged in a predicted operon (32). (B) Growth of C. burnetii in ACCM-D, ACCM-D minus arginine, or ACCM-D minus arginine and supplemented with citrulline was assessed using qPCR to quantitate genome equivalents (GE) during a 14-day incubation. The results are expressed as the means of the results from three independent experiments, and the error bars indicate the standard deviations.