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M Daffé

Publications and source records attributed to M Daffé.

68 records · Page 4Linked to original sources
PubMed1987

Structure of the major triglycosyl phenol-phthiocerol of Mycobacterium tuberculosis (strain Canetti).

Phenol-phthiocerol glycolipids have been found previously in Mycobacterium leprae, M. kansasii, M. bovis and M. marinum, but not in M. tuberculosis. A search for glycolipids in this latter species showed that the Canetti strains of M. tuberculosis synthesize a major triglycosyl phenol-phthiocerol, accompanied by minor amounts of other glycolipids with a similar aglycone moiety. The triglycoside moiety has the following structure: 2,3,4-tri-O-methyl L-fucopyranosyl(alpha 1----3)L-rhamnopyranosyl(alpha 1----3)2-O-methyl L-rhamnopyranosyl(alpha 1-. The aglycone moiety consists in phenol-phthiocerol (two homologs). Its two secondary alcohol functions are esterified by mycocerosic acids (homologs with 26-32 carbon atoms and with 2-4 methyl branches). The proposed structure differs on several points from the M. leprae glycolipids, but presents some analogy with the major glycolipid of M. kansasii. A minor monoglycosyl phenol-phthiocerol was also studied. Its overall structure is very similar to that of M. bovis, with 2-O-methyl rhamnose as sugar moiety.

Antigens, Bacterial↗
PubMed1987

[Structural and metabolic study of the mycolic acids of Mycobacterium fortuitum].

The biosynthesis of mycolic acids was studied in whole cells of Mycobacterium fortuitum. At first the structures of the main mycolates produced by the used strain were established as diunsaturated and epoxymycolates. By using [1-14C]acetate as a radiotracer of the lipid synthesis, it was observed that the turnover of the mycolates during the exponential phase of growth of M. fortuitum is fast enough to make very difficult the identification of their precursors. If the growth of the bacterial cells is stopped or highly diminished, by the removal of a large part of their nutritional medium, mycolate synthesis, in contrast to the synthesis of other fatty acids, is stopped as shown by incubation of the concentrated bacterial culture with [1-14C]acetate. After removal of aliquots of the sedimented bacteria at intervals, during several hours, mycolate synthesis resumes when the cell concentration becomes lighter. In these conditions the sequence of radiolabeling of mycolates and of their potential precursors (tetracosanoate and meromycolates) can be observed. In spite of their low accumulation, tetracosanoate and meromycolates were isolated and purified and their specific radioactivity, after different incubation times, could be measured. The results are in agreement with the hypothesis that meromycolates are condensed with tetracosanoate to produce mycolates. However, because of the large differences of isotopic dilution of these two precursors inside the mycolate molecule, this hypothesis, generally taken as evidence, has to be modified. A hypothetical pathway of the mycolate synthesis is proposed, taking into account all these observations.

Acetates↗
PubMed1986

A cooperative taxonomic study of mycobacteria isolated from armadillos infected with Mycobacterium leprae.

Seventeen strains of mycobacteria, recovered from six armadillos experimentally infected with Mycobacterium leprae, were examined in ten different laboratories. This collaborative study included use of conventional bacteriological tests, lipid analyses, determination of mycobactins and peptidoglycans, characterization by Py-MS, and immunological, metabolic, pathological and DNA studies. These armadillo-derived mycobacteria (ADM) formed five homogeneous groups (numbered ADM 1 to 5) on the basis of phenetic analyses. However, DNA studies revealed only four homogeneous groups since group ADM 1 and one of the two strains in group ADM 3 showed a high level of DNA relatedness. The phenetic and DNA studies confirmed that the ADM strains differed from all other known mycobacteria. Cultural, biochemical, metabolic and pathogenic properties as well as DNA-DNA hybridizations clearly differentiated these ADM from M. leprae.

Amino Acids↗
PubMed1984

Induction of polyploid nuclei in the plasmodium of Physarum polycephalum by platinum antitumor compounds.

The intranuclear mitosis of the plasmodial nuclei of myxomycetes permits the observation of defects in chromosomal repartition which would probably be lethal in other eukaryotic cells with open mitosis. We found that antitumoral platinum-amine compounds perturbed late mitotic events and induced the formation of giant nuclei which were polyploid in plasmodia of Physarum polycephalum. Using 26 platinum-amine complexes, we have shown that all antitumoral compounds induced the formation of polyploid nuclei for drug concentrations at least three times lower than the amount necessary to block the overall plasmodial growth, whereas platinum compounds without antitumor activity did not behave this way. DNA replication appeared to be quantitatively normal during formation of giant nuclei by antitumoral compounds. These observations suggest that platinum-amine compounds exert their antitumor activity by interfering with mitosis rather than by a gross inhibition of DNA synthesis.

Cell Nucleolus↗
PubMed1983

Identification of Mycobacterium fortuitum and Mycobacterium chelonei.

The study of 52 strains of rapidly growing mycobacteria showed that Mycobacterium fortuitum and M. chelonei were clearly distinguished by the aid of seven key tests (nitrate reductase, iron uptake, beta-glucosidase, penicillinase, growth on fructose, resistance to pipemidic acid, and resistance to capreomycin) and by analysis of their respective mycolic acids. However, the subdivision of these species into M. fortuitum var. fortuitum and M. fortuitum var. peregrinum and M. chelonei subsp. chelonei and M. chelonei subsp. abscessus was not satisfactorily accomplished.

Capreomycin↗
PubMedDate not supplied

Differentiation of Mycobacterium thermoresistibile from Mycobacterium phlei and other rapidly growing mycobacteria.

Mycobacterium thermoresistibile is the only chromogenic rapidly growing mycobacterial species reported to cause infections in humans and animals. DNA-DNA hybridization (S1 nuclease method) showed that M. thermoresistibile formed a DNA relatedness group which was only 24 to 30% related to M. phlei. Alkaline phosphatase and beta-galactosidase differentiated M. thermoresistibile from M. phlei. Among the rapidly growing mycobacteria, the mycolic acid pattern of M. thermoresistibile was unique (alpha-, alpha'-, methoxy-and keto-mycolates). Fourteen other species of chromogenic rapidly growing mycobacteria, including M. phlei, produced different mycolic acid patterns which always included dicarboxylic mycolate. Nine species of non-chromogenic rapidly growing mycobacteria produced mycolic acid patterns devoid of ketomycolate.

Alkaline Phosphatase↗
PubMedDate not supplied

Taxonomy of mycobacterial strains isolated from the tissues of leprosy patients.

Thirty-six slowly growing mycobacteria isolated from the tissues of leprosy patients were studied using 40 characteristics as well as susceptibility to 27 distinct mycobacteriophages. The composition in mycolic acids of selected strains was also studied. According to the data, the strains formed 5 clusters. Some of the clusters were possibly as yet undescribed species; however, comparison of the data with the known properties of Mycobacterium leprae leads to the conclusion that none of the strains were identical to the leprosy bacillus.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Lipid composition of cultivable Mycobacteria isolated from livers of armadillos infected by Mycobacterium leprae].

Four bacterial strains isolated from two livers of armadillos experimentally infected with Mycobacterium leprae were studied. Lipids obtained after saponification and methylation and complex lipids obtained by solvent extraction were examined. The presence of mycolates showed that the four strains belonged to the genus Mycobacterium, but the mycolate patterns, identical for the four strains, were different from those of all strains studied so far. Three of these strains contained phthioceranic acids, which were not found in the fourth one. Only the last strain contained mycosides of the C type, while the three others contained a new type of glycolipid. Their content in mycolates and in glycolipids demonstrated a clear-cut difference between these strains, on the one hand, and M. leprae on the other.

Animals↗
PubMedDate not supplied

Lipids as taxonomic markers for bacteria derived from leprosy infections.

Lipid analysis allows the specific detection of M. leprae among various other bacteria isolated from leprosy lesions. In this report mycolates and glycolipid compositions were used for such a discrimination. Comparative studies of the lipid composition of tissue fragments from different organs of experimentally infected armadillos, and of cultivable strains isolated from these tissues showed that the last ones did not multiply extensively in the tissues of the animals.

Animals↗
PubMedDate not supplied

[Taxonomic value of mycobacterial fatty acids: proposal for a method of analysis].

A simple and quantitative method for the alkaline hydrolysis of fatty acid derivatives occurring in the lipids of mycobacteria is described. After methylation, the lipidic mixtures were chromatographed on a thin layer of silicagel. The contents in mycolates and secondary alcohols allowed the distinction of 9 groups among the 27 species studied. Such an analysis is generally insufficient to identify a species, but its discriminating power differs from that of other commonly-used methods. Complementary tests chosen according to each particular situation are necessary, including vapour phase chromatography applied to the same lipidic mixture as that used for thin-layer chromatography. Coupling of the two chromatographic methods would allow the recognition of 22 groups among the 27 species of mycobacteria studied.

Chromatography, Gas↗
PubMedDate not supplied

[Specific lipids from Mycobacterium ulcerans].

The main lipids synthesized by Mycobacterium ulcerans are specific for the species. Three products were isolated by chromatography. Their structures were determined by means of spectrographic methods performed on the natural substances or on their split products. The most abundant products were phthiodiolone diphthioceranate and phenolphthiodiolone diphthioceranate . These structures have some analogies with those of phthiocerol dimycocerosate synthesized by M. tuberculosis and M. bovis, and with those of phenolphthiocerol mycocerosate synthesized by M. bovis. The reverse configuration of the polymethyl-branched-chain fatty acids isolated from the substances, according to their origin, remains to be pointed out. Little attention has generally been paid to the stereochemistry of such molecules. We verified that the branched-chain fatty acids found in diacyl phthiocerol and in the mycoside of M. leprae have the same configuration as in the analogous molecules isolated from M. tuberculosis or M. bovis, contrary to M. ulcerans. Another peculiarity of phenolphthiodiolone isolated from M. ulcerans is the occurrence of the phenol group in free form.

Chemical Fractionation↗
PubMedDate not supplied

[Lipidic constituents of "Mycobacterium leprae" isolated from experimentally infected armadillo (author's transl)].

Mycobacterium leprae (obtained from experimentally infected armadillo) was submitted to saponification. The liposoluble part was methylated and fractionated by chromatographic methods. Each fraction was studied by gas-liquid chromatography. Cholesterol (from the infected host) and the main fatty acids were identified. Mycolic acids were isolated, and their structures determined, using mass spectrometry. These structures are useful to make a comparison of M. leprae with some other mycobacteria. Some of these comparisons are discussed here. The absence-or, at least, the very low level-of tuberculostearate suggests comparative studies of M. leprae and M. gordonae.

Animals↗
PubMedDate not supplied

[Studies on the lipids of "Mycobacterium gordonae" in comparison with those of "M. leprae" and of some other scotochromogenic mycobacteria (author's transl)].

The mycolic acids were isolated from Mycobacterium gordonae (strain ATCC 14470), and purified by thin layer chromatography. Three species were studied by mass spectrometry. The analogy between M. gordonae and M. leprae, based on the lack of tuberculostearic acid, was supported by the comparison of the structures of their mycolic acids. Succinct analyses of the lipids of three other scotochromogenic strains of mycobacteria, using thin layer chromatography and gas-liquid chromatography, were performed. These strains were more remote from M. gordonae than is M. leprae, as far as the lipid content is concerned.

Chromatography↗