FIG. 4.
Thin-layer chromatography of FAMEs and MAMEs from various strains of M. tuberculosis. M. tuberculosis, MtbΔvirS, Mtbmym::hyg, and MtbΔvirS_virS strains were grown to an A600 of 1.5 in MB 7H9 medium, adjusted either to pH 7.0 or to pH 5.0, and labeled with 1 μCi/ml [1,2-14C]acetate for 12 h. Labeled lipids were extracted, derivatized to methyl esters, and resolved by normal phase TLC using petroleum ether/diethyl ether (17:3). Equal counts (200,000 cpm) were loaded in each lane, and a phosphorimager was used to quantify the proportion of FAMEs and MAMEs derived from various strains of M. tuberculosis. Shown are TLC profiles of total fatty acid esters (FAMEs and MAMEs) extracted from M. tuberculosis, MtbΔvirS, Mtbmym::hyg, and MtbΔvirS_virS strains growing at (A) neutral pH (7.0) or (B) acidic pH (5.0). These experiments were repeated four times, and similar results were obtained.