Figure 5. Mtb Δfcr mutants are impaired in WE biosynthesis under combined MS.

A, Diminished incorporation of ¹⁴C-oleate into WE in Mtb Δfcr mutants under combined MS treatment. Mtb cultures exposed to combined MS for 9 days were metabolically labeled with ¹⁴C-oleic acid for 4 h. Total lipids (equal proportions across samples) were resolved on silica-TLC and autoradiograms from a typical experiment is shown. WT, wild type Mtb; d-fcr1, fcr1-deletion mutant; C-fcr1, complemented fcr1 mutant; d-fcr2, fcr2-deletion mutant; C-fcr2, complemented fcr2-deletion mutant. Arrows indicate relative positions of authentic lipid standards. WE, wax esters; TG, triacylglycerols; FA, fatty acids; FA-OH, fatty alcohols, PL, polar lipids. B. Loss of fcr1 or fcr2 results in diminished wax ester biosynthesis under combined MS. Complementation restores WE biosynthesis in fcr1-deletion mutant only. Radioactivity from ¹⁴C-oleate incorporated into fatty alcohol and WE after 9 days under combined MS was determined and normalized as percent of total radioactivity in the respective lipid extract. Values are average ± SD.