Variantes de mycosides caracterisees par des residus glycosidiques substitues par des chaines acyles-I: Spectres de masse des mycosides G′ et A′ peracetyles

Characterisation of phenolic glycolipids from Mycobacterium marinum

The phenolic glycolipids from two strains of Mycobacterium marinum have been isolated and characterised. The glycolipids from M. marinum MNC 170 were principally glycosides of diacyl C37, C39 and C41 phenolphthiocerols A, but in M. marinum MNC 842, these lipids were accompanied by glycosides of diacyl phenolphthiodiolones A and novel phthiotriols A with the same overall chain-lengths. The main acyl components of the phenolic glycolipids from M. marinum MNC 170 were C26 dimethyl and C27 and C29 trimethyl-branched fatty acids, but in the lipids of M. marinum MNC 842, the C27 trimethyl acid was the only principal component. The sugar composition of all these glycolipids had been previously shown to correspond to 3-O-methylrhamnose.

Monoglycosyldiacylphenol-phthiocerol of Mycobacterium tuberculosis and Mycobacterium bovis

The structure of a minor glycolipid of M. tuberculosis (strain Canetti) is shown to be 2-O-methyl-alpha-L-rhamnosyldiacylphenol-phthiocerol. A similar compound with non-methylated rhamnose as sugar moiety was also detected. In the course of this work, the structure of mycoside B from Mycobacterium bovis was reexamined, and was shown to be identical to that of the 2-O-methylrhamnosyldiacylphenol-phthiocerol of the Canetti strain, while it was described as a 2-O-methyl-beta-D-rhamnosyl derivative in the literature. This result is in agreement with the known close relationship between M. tuberculosis and M. bovis. Careful examination of chromatographic fractions containing the above mentioned lipids showed that the occurrence of mycoloyl residues in some phenol-phthiocerol glycolipids, postulated in the literature, was likely to be due to the presence of glycerol monomycolate contaminants.

Analysis of dimycocerosates of glycosylphenolphthiocerols in the identification of some clinically significant mycobacteria

Extracts of representative mycobacteria were examined by thin-layer chromatography for glycosylphenolphthiocerol dimycocerosates. The glycolipid typical of Mycobacterium bovis was also found in Mycobacterium africanum and Mycobacterium microti, but it was absent in Mycobacterium bovis AN 5. Mycobacterium gastri strains contained a glycolipid which was chromatographically similar to that in Mycobacterium kansasii. Representatives of Mycobacterium marinum produced a distinct glycolipid type, and one strain had major amounts of a more polar variant. The sugar moieties of purified lipids, including that from Mycobacterium leprae, were identified by thin-layer chromatography of methyl glycosides in acid methanolysates.