Figure 4. Dose-response effects of TAC and related analogues on mycolic acid biosynthesis in M. tuberculosis.
The inhibitory effect on the incorporation of [2-14C]acetate was assayed by labeling in the presence of increasing concentrations of TAC, 15 or 16. The corresponding fatty acid methyl esters (FAME) and mycolic acid methyl esters (MAME) were extracted and equal counts were loaded onto a TLC plate. (A) 1D TLC profile of MAMEs. Radiolabeled lipids (40,000 cpm) were resolved with hexane/ethyl acetate (19/1, v/v, 2 runs) and exposed overnight to a film. (B) 2D TLC profile of MAMEs. Radiolabeled lipids (30, 000 cpm) were resolved with hexane/ethyl acetate (19/1, v/v, 2 runs) in the first dimension and petroleum ether/diethyl ether (17/3, v/v, 3 runs) in the second direction on 10% silver nitrate-impregnated plates and exposed for two days to a film. Α, α-mycolates; keto, ketomycolates, methoxy, methoxymycolates. Arrowheads indicate positions of the unsaturated mycolic acid species. OAME, oleic acid methyl ester.