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M Daffé

Publications and source records attributed to M Daffé.

At least 55 records · Page 3Linked to original sources
PubMed1992

The phenolic mycoside of Mycobacterium ulcerans: structure and taxonomic implications.

Mycobacterium ulcerans and some pathogenic mycobacterial species elaborate wax A consisting of related long-chain beta-diol components (phthiocerol and related compounds) esterified by multimethyl-branched fatty acids. With the exception of M. ulcerans, wax A-containing mycobacteria also synthesize glycosylated phenol phthiocerol diester and related compounds: the so-called phenolic mycosides. In a deliberate effort to characterize this latter class of compounds in M. ulcerans, 20 strains were examined. Phenolic mycosides were found in two strains. Application of chemical analyses, including one- and two-dimensional NMR spectroscopy, allowed the structural elucidation of glycolipids identified as 3-O-methyl-alpha-L-rhamnosyl phenol phthiocerol diphthioceranate investigators. As phenolic mycosides are highly species-specific molecules, this finding stresses the close phylogenetic link between M. marinum and M. ulcerans. Incidentally, a survey of the mycolate content of M. ulcerans showed that methoxymycolate could not be detected in three strains.

Fatty Acids↗
PubMed1992

Lack of correlation between colony morphology and lipooligosaccharide content in the Mycobacterium tuberculosis complex.

Rough and smooth colony variants of the Mycobacterium tuberculosis complex were compared with respect to their composition in trehalose-containing glycolipid antigens in view of the results of a recent investigation suggesting that the chemical basis of rough and smooth colony morphology in mycobacteria may reside in the occurrence of lipooligosaccharides. A careful chemical characterization of the individual glycolipids of the selected strains allowed the identification of the major glycolipids. The comparative study of the glycolipid content of the smooth Canetti strain, its spontaneous rough variant, and 16 additional strains of M. tuberculosis, M. bovis and M. africanum showed that the presence of lipooligosaccharides was not related to the morphology of the colonies.

Glycolipids↗
PubMed1991

Glycopeptidolipids from Mycobacterium fortuitum: a variant in the structure of C-mycoside.

Strains from the Mycobacterium fortuitum complex contain surface species-specific lipids allowing their precise identification. In M. fortuitum biovar. peregrinum two major glycopeptidolipids, of the C-mycoside type, were characterized by a combination of chemical analyses, NMR, and FAB mass spectrometry. Important information was obtained by mass spectrometry both on their molecular weight and on the peptide and saccharide sequences without any derivatization. The basic structure of the two compounds was shown to be [formula: see text] The disaccharide part linked O-glycosidically to alaninol was either 3,4-di-O-methyl-alpha-L-rhamnopyranosyl (1----2) 3,4-di-O-methyl-alpha-L-rhamnopyranoside (mycoside I) or 3-O-methyl-alpha-L-rhamnopyranosyl (1----2) 3,4-di-O-methyl-alpha-L-rhamnopyranoside (mycoside II). This is an unusual structure of a C-mycoside since neither 6-deoxytalose nor its derivatives are present. Moreover, the oligosaccharide part is linked to the alaninol residue instead of the allo-threonine.

Chromatography, Thin Layer↗
PubMed1991

Revised structure of a trehalose-containing immunoreactive glycolipid of Mycobacterium tuberculosis.

Nuclear magnetic resonance spectroscopy, fast-atom bombardment mass spectrometry as well as various chemical degradations and chromatographic techniques were used to re-examine the structure of a highly immunoreactive glycolipid previously described in Mycobacterium tuberculosis (strain Canetti) as a 2,3-diacyl trehalose 2'-sulfate (labelled SL-IV). Ion exchange chromatography allowed the recognition of a neutral and an acidic glycolipid, indistinguishable on conventional silica gel. The neutral glycolipid was shown to be serologically identical to SL-IV and its structure was established as 2,3-diacyl trehalose. It corresponded to the non-chemically defined highly observed immunoreactive lipid previously recognized by others in M. tuberculosis (H37Rv).

Antigens, Bacterial↗
PubMed1991

Structure and stereochemistry of mycolic acids of Mycobacterium marinum and Mycobacterium ulcerans.

Mycobacterium marinum and M. ulcerans were previously shown to synthesize lipid compounds which are stereochemically different from the corresponding molecules isolated from M. tuberculosis and other species. Stereochemical and biogenetic studies of mycolic acids isolated from M. marinum showed that the absolute configurations of the chiral centres occurring in the mycolates are identical to those of the other mycobacterial species examined so far. Furthermore, all the methyl branches were found to come from methionine whatever the configuration of the centre. The structures of the mycolates synthesized by M. marinum and M. ulcerans were found to be identical, consisting of dicyclopropyl and monocyclopropyl monoenoic mycolates, monoenoic keto- and methoxymycolates, thus reinforcing the taxonomical relationship between the two species.

Magnetic Resonance Spectroscopy↗
PubMed1991

Further stereochemical studies of phthiocerol and phenol phthiocerol in mycobacteria.

Mycobacterium tuberculosis, M. marinum and some other pathogenic species elaborate waxes A, based on a long-chain beta-diol (phthiocerol and companion compounds) and polymethyl-branched fatty acids. The stereochemical studies conducted on waxes A showed that those of M. tuberculosis, M. leprae and M. kansasii differ from waxes A isolated from M. marinum and M. ulcerans by the absolute configuration of the methyl-branched chiral centres occurring in both the long-chain beta-diols and the fatty acyls. Furthermore, the two mycobacterial groups also differ in the stereochemistry of the beta-diol chiral centres.

Fatty Alcohols↗
PubMed1989

Scalar, dipolar-correlated and J-resolved 2D-NMR spectroscopy of the specific phenolic mycoside of Mycobacterium tuberculosis.

Two-dimensional chemical shift correlated (COSY), nuclear Overhauser (NOESY) and J-resolved spectroscopy were used to determine the complete structure of the major triglycosyl dimycocerosyl phenol phthiocerol of the tubercle bacillus (strain Canetti) without any other analytical technique. The COSY spectrum of the native glycolipid allowed the composition of the trisaccharide and the location of one methoxyl group to be determined through the assignment of the resonances of the non-anomeric methine protons. Information with respect to the configuration of the sugar residues, the pyranose structure and the linkage sites of the trisaccharide were obtained by the analysis of the COSY spectrum of the peracetylated glycolipid. The NOESY spectrum confirmed the linkage sites through the inter-residue connectivity across glycosidic linkages and allowed the determination of the sequence of the oligosaccharide and the configuration of its sugar residues from the through-space connectivities. The J-resolved spectroscopy was used to elucidate the structure of the glycolipid and gave additional data showing the presence of 11 non-equivalent methyl groups and allowing the recognition of two other analogues of the phenol phthiocerol derivative in the mixture. Thus, the non-destructive 2D-NMR spectroscopy was found to be satisfactory for the analysis of mycobacterial mycosides.

Glycolipids↗
PubMed1989

Diglycosyl phenol phthiocerol diester of Mycobacterium leprae.

A diglycosyl phenol phthiocerol diester that had not been previously detected was isolated from M. leprae-infected armadillo tissues. Spectroscopy methods allowed the elucidation of its structure. The diglycoside was a 2,3-di-O-methylrhamnopyranosyl (alpha 1----2)3-O-methylrhamnopyranosyl (alpha 1-linked to the phenolic hydroxyl of phthiocerol dimycocerosates). It differs from the major phenolic glycolipid (PGL I) only by the absence of the terminal 3,6-di-O-methylglucopyranosyl unit. The diglycoside could be an intermediate in the synthesis of the latter antigen or a degradative product in the host detoxification process.

Animals↗
PubMed1989

Further specific triglycosyl phenol phthiocerol diester from Mycobacterium tuberculosis.

Mono- and two-dimensional 1H-NMR allowed the structural elucidation of a glycolipid belonging to the phenolic mycosides series: 2,3,4-tri-0-methyl fucopyranosyl (alpha 1----3) rhamnopyranosyl (alpha 1----3) rhamnopyranosyl (alpha 1----dimycocerosyl) phenol phthiocerol. It shares with the major phenolic glycolipid the two terminal sugar residues, suggesting its potential antigenicity. The glycolipid may also represent an intermediate in the biosynthesis of the major one.

Acetylation↗
PubMed1989

Glycolipids of recent clinical isolates of Mycobacterium tuberculosis: chemical characterization and immunoreactivity.

Five distinct glycolipids were readily detected in isolates of Mycobacterium tuberculosis. Spectroscopic methods and chemical degradation techniques allowed the structural identification of four of these glycolipids. The specific phenolic glycolipid antigen previously characterized from the Canetti strain was found in all the strains examined, with identical structural features (triglycosyl phenol phthiocerol dimycocerosate). The other three glycolipids identified were acylated trehaloses: penta-acyl trehalose (containing phthienoyl substituents), tetra-acyl trehalose 2'-sulphate (with C40-C50 hydroxyphthioceranoyl substituents) and diacyl trehalose 2'-sulphate (with C16 and C18 substituents). The two latter glycolipids as well as the phenolic glycolipid immunoreacted with whole-cell antiserum, indicating their surface location. The occurrence of these glycolipid antigens in recent clinical isolates suggests their possible utilization in the serodiagnosis of tuberculosis and the rapid identification of M. tuberculosis with specific antisera.

Chromatography, Thin Layer↗
PubMed1989

Specificity and antigenicity of mycoside G and other glycolipids from Mycobacterium marinum.

The purpose of this work was to examine the immunologic properties of the phenolicglycolipid produced by M. marinum (mycoside G). Cell mass processed with organic solvents yielded a lipid extract containing mycoside G and four other glycolipid fractions (G2 to G5). No mycoside G was found in the Mycobacterium marinum type strain. Neither mycoside G, nor fractions G2, G3 and G4 were immunogenic in the rabbit whereas fraction G5 was very immunogenic. The immune serum raised in the rabbit showed that fraction G5 is species specific since it was consistently detected in all Mycobacterium marinum strains examined so far.

Animals↗
PubMed1989

Serological specificity of Mycobacterium tuberculosis glycolipids.

Six glycolipid fractions can be extracted from lipid crude extracts of Canetti type strains of M. tuberculosis. Among these fractions are two phenolglycolipids. The major component is a triglycosyl phenolphthiocerol dimycocerosate (PGL-Tb 1) and the second is a monoglycosyl diacyl phenolphthiocerol identical to mycoside B of M. bovis. Similar glycolipid compounds can also be found in wild strains of M. tuberculosis recently isolated from tuberculous patients. One of these compounds has been identified as PGL-Tb 1.

Antibodies, Bacterial↗
PubMed1988

Mycolic acids of Mycobacterium aurum. Structure and biogenetic implications.

Mycobacterium aurum (type strain) was analyzed for its mycolate content. Three types of mycolates were identified: di-unsaturated, oxo and dicarboxy mycolates, each type being constituted by two subtypes. The acid released by pyrolysis was identified as docosanoic acid. By use of mass spectrometry and oxidation techniques, the structures of these six subtypes of mycolates were elucidated. They contain Z and E double bonds, the latter having an adjacent methyl branch. No cyclopropane ring was observed. All the methyl branches occurring in these mycolates derived from methionine, the methyl-branched chiral center adjacent to the double bond having an R configuration. The structures of the major di-unsaturated mycolates suggest that they cannot be the precursors of oxo mycolates. The amount of long-chain secondary alcohol (2-octadecanol) obtained from the whole cells was found to be much greater than that expected from hydrolysis of wax ester mycolate (ester of 2-octadecanol and dicarboxy-mycolic acid). Further investigations showed that 2-octadecanol was also present in triacylglycerols, esterifying the omega-carboxyl group of long-chain fatty acids structurally related to dicarboxy-mycolates.

Hydrolysis↗
PubMed1988

Tetraenoic and pentaenoic mycolic acids from Mycobacterium thamnopheos. Structure, taxonomic and biosynthetic implications.

On the basis of the analysis of mycolates, the type strain of Mycobacterium thamnopheos has been considered as a member of the genus Nocardia. In a comparative study conducted on mycobacterial species we found that M. thamnopheos synthesized two types of mycolate having the same mobilities on thin-layer chromatography as those of mycobacteria, but different from nocardomycolates. Mass spectrometry analyzes showed that the major series of both types consisted of polyunsaturated mycolic acids, ranging from C72 to C78 with four or five double bonds. On pyrolytic mass spectrometry or gas chromatography, the least polar mycolates released mainly monounsaturated C22 esters whereas the other type yielded saturated C20 and C22 esters. These results suggested that M. thamnopheos might be more related to the Aurantiaca taxon than to mycobacteria and Nocardia. The permanganate-periodate oxidation products of esters obtained by pyrolysis of the least polar mycolates showed that they contained docosen-4-oic and docosen-6-oic acids. Both types of mycolate esters yielded the same set of long-chain meroaldehydes on pyrolysis. These meroaldehydes were significantly distinct from those of mycobacterial mycolates in the location of the double bonds. After hydrogenation of the double bond located in the alkyl-branched chain, the two types of mycolates had the same mobility on thin-layer chromatography, indicating that the difference of migration was due to the additional double bond found in the least polar mycolates. Based on stereochemical data, the relative configuration of both mycolates was found to be threo, like that established for all mycolates studied so far.

Chromatography↗
PubMed1988

Polyphthienoyl trehalose, glycolipids specific for virulent strains of the tubercle bacillus.

Phthienoic acids constitute a family of dextro-rotary odd-numbered unsaturated fatty acids isolated exclusively from virulent strains of human and bovine tubercle bacilli. In the bacterial cell they are not free and a search for their linked form in complex wall lipids of Mycobacterium tuberculosis (strain Canetti) showed that they esterified trehalose. Structural elucidation of the major phthienoyl trehalose showed the occurrence of five acyl residues located at 2, 2', 3', 4 and 6' positions of trehalose. The acyl substituents were mainly 2,4,6-trimethyl tetracos-2-enoic acid (C27 phthienoic acid) accompanied by its homologs. In addition to these branched fatty acids, straight-chain C16 and C18 acyls composed about 20% of the substituents. The proposed structure is a new one, both for the mycobacterial-specific glycolipid and for the substituted positions on trehalose. Other minor acyl trehaloses were detected in M. tuberculosis (strain Canetti), differing from the major component by the occurrence of an additional hydroxy fatty acid (3-hydroxy-2,4,6-trimethyl tetracosanoic acid) or by the number of acyl substituents. The major glycolipid presented a weak activity in vitro on mitochondrial oxidative phosphorylation. These glycolipids and phthienoic acids could serve as virulence indicators.

Acylation↗
PubMed1988

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.

Carbohydrates↗
PubMed1988

Distribution of phthiocerol diester, phenolic mycosides and related compounds in mycobacteria.

Among 28 mycobacterial species studied, only Mycobacterium tuberculosis, M. bovis, M. africanum, M. marinum, M. kansasii, M. gastri and M. ulcerans produced waxes yielding long-chain beta-diol components (called phthiocerol and companions) and polymethyl-branched fatty acids on saponification. The same mycobacterial species also produced diesters of phenol phthiocerol and companions. Fatty acids esterifying these fatty alcohols in M. marinum and M. ulcerans were found to belong to the phthioceranic series (dextrorotatory fatty acids), in contrast to those of the other species (laevorotatory fatty acids called mycocerosic acids), both groups having the same chain length and methyl-branched positions. M. kansasii and M. gastri contained the same waxes with identical structures, as did M. tuberculosis, M. bovis and M. africanum. Neither the type strain of M. tuberculosis, nor that of M. bovis or M. marinum accumulated the strain-specific phenolic glycolipids.

Fatty Alcohols↗