FIGURE 2.

Fatty acids of differing chain lengths rescue the Δicl1 strain from propionate toxicity. Acetate, short chain fatty acids, and long chain fatty acids similar to those found in the host macrophage can rescue propionate toxicity in Δicl1 Mtb. A and B, the C2 compound, acetate, rescues propionate toxicity in Δicl1 Mtb in a dose-dependent manner. Bacteria were grown for 18 days in medium containing 10 mm glycerol (G) and 0.05 mm propionate supplemented with acetate across the range from 0.05 to 4 mm. C, short to mid-length and long chain fatty acids also rescue propionate toxicity in Δicl1 Mtb. Bacteria were grown for 18 days in medium containing 10 mm glycerol and 0.05 mm propionate (GP) supplemented with saturated even chain length fatty acids (C2–C24) at the following concentrations. Acetate (C2) was added at 1 mm, short chain fatty acids (C4–C8) at 0.5 mm, and intermediate and long chain fatty acids (C10–C24) at 0.05 mm. Bacterial growth was measured by absorbance at 600 nm, and results are representative of three replicates. Error bars, Standard Deviation.