Mtb cells under multiple-stress incorporate [14C]oleic acid primarily into triglycerides.

At 0, 9 or 18 days under multiple-stress, Mtb cultures were metabolically labeled with [1-14C]oleic acid for 6 h and total lipids were extracted and resolved on TLC as described previously [12] using hexane∶diethyl ether∶formic acid (80∶20∶2, v/v/v) as the solvent system. Regions of the TLC plates corresponding to standard triolein (for triglycerides) or oleyl oleate (for wax esters) or the origin (for polar lipids) were scraped and radioactivity was quantified by liquid scintillation counting. Radioactivity in individual lipid subclasses is expressed as a fraction of the radioactivity in total lipid extracts prior to TLC procedures.