Phthiocerol dimycocerosate

The distribution of these substances in the various species of Mycobacteria is as follows. (a) Phthiocerol dimycocerosate is present in the lipids of 28 out of 30 human strains studied, (b) A compound first called Gb is present in the lipids of 7 out of 7 bovine strains studied (Gb is accompanied by phthiocerol dimycocerosate in virulent, bovine strains), (c) A compound first called Ga is present in the lipids of 17 out of 17 photochromogenic strains, (d) A compound first called Jav is present in the lipids of 11 out of 13 avian strains, and also in the lipids of 3 out of 6 non-photochromogenic strains. 

Specific polyketide hpids present in M. tuberculosis interact with the host and are required for virulence. Mass spectrometric analysis was conducted to monitor this type of lipids [53]. It was discovered that the size and abundance of two lipid virulence factors, phthiocerol dimycocerosate and sulfolipid-1, were controlled by the availability of a common precursor, methyl malonyl CoA. These results suggested that growth of M. tuberculosis on fatty acids during infection led to increased flux of methyl malonyl CoA through lipid biosynthetic pathways, resulting in increased virulence lipid synthesis. 

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