FIG. 5.

Effects of individual carbon source levels on C. burnetii metabolic activity. The effect of supplementing CCM with efficiently oxidized carbon sources (16) on C. burnetii de novo protein synthesis was measured. Organisms were incubated for 3 h in CCM containing [³⁵S]Cys-Met and supplemented with 1 or 5 mM glutamate, succinate, or pyruvate. Incorporation of radiolabel was quantified by scintillation counting and is expressed as the increase relative to the incorporation of C. burnetii incubated in CCM (pH 7.0) (negative control). Asterisks indicate statistically significant (P < 0.05) differences between radiolabel incorporation by C. burnetii incubated in CCM and in CCM supplemented with a 1 or 5 mM concentration of the carbon source. The broken line represents the level of radiolabel incorporation in CCM (pH 7.0) normalized to 1.