Figure 5. Fatty acid composition analysis confirms that Mtb incorporates host TAG-derived fatty acids directly into TAG.

A and B, Macrophage TAG labeled with [¹⁴C]oleate is utilized by Mtb for TAG accumulation. A, AgNO₃-TLC of methyl esters of fatty acids (FAMEs) prepared from TAG of Mtb-infected macrophages (lane 1, from left) and TAG from Mtb recovered from such macrophages (lane 2). B, Reversed-phase TLC analysis of FAMEs prepared from macrophage TAG (lane 1) and Mtb TAG (lane 2). Autoradiograms of the TLC plates with authentic ¹⁴C-labeled C16:0, C18:0, C18:1 and C20:4 FAMEs are shown. The AgNO₃-TLC and reversed-phase TLC show that ¹⁴C-oleic acid is incorporated into THPM TAG which is utilized to accumulate [¹⁴C]oleate-labeled TAG inside Mtb. C, FAMEs prepared from THPM and Mtb TAG analyzed using a Varian CP-TAP CB capillary column attached to a Varian CP-3900 gas chromatograph under a temperature control program. Mtb TAG FAMEs are identical to THPM TAG FAMEs except for very long-chain derivatives seen only in the TAG from the pathogen.