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J Asselineau

Publications and source records attributed to J Asselineau.

At least 19 recordsLinked to original sources
PubMed1998

Mycobacterial lipids: a historical perspective.

Mycobacterial lipids have been studied for more than 70 years, due to the fascinating diversity of their structures and biological activities. A historical perspective, and the present status on the structure and activity of major lipids of the outer envelope of mycobacterial cells are presented : mycolic acids, which are main constituents of the cell wall, and glycolipids known for toxic or immunological properties (cord factor, SL, DAT, PGL, GPL, LOS, LAM). As far as possible, it was tried to distinguish between experimentally established knowledge and currently accepted speculations.

Carbohydrate Sequence↗
PubMed1990

[Chemotaxonomy of gram-positive bacteria metabolizing beta-caryophyllene].

Chemotaxonomic identification of coryneform bacteria metabolizing b-caryophyllene was attempted. The following phospholipids were identified as main components of the bacterial extracts: cardiolipids, phosphatidylethanolamine, phosphatidylinositol and mannosides of phosphatidylinositol. Saponification of the lipid extracts gave a mixture of hydroxylated and nonhydroxylated fatty acids. Among the latter, oleic and tuberculostearic acids were identified. The hydroxylated fatty acids were analysed by thin-layer chromatography and mass spectrometry (as methyl esters). From the results thus obtained, the strains appeared to be more closely related to the genus Rhodococcus than to the genus Nocardia.

Chromatography, Gas↗
PubMed1990

[Lipid analysis in bacterial taxonomy: proposal for a standardized method].

To increase the application of lipid analysis for taxonomic purposes, a standardized method would be useful. This method has to be simple enough to be used routinely. Such a method, based on thin-layer and gas chromatography, is proposed. It can be applied to any kind of bacteria when a few milligrams of cells are available. Comparison of the results provided by this analysis with data found in the literature (given in a schematic form in six tables) allows the identification of the studied strain in the most favorable cases, or gives information for the choice of conclusive complementary tests in the other cases.

Bacteria↗
PubMed1985

Glycolipids from Nocardia rhodochrous grown on glucose.

Nocardia rhodochrous grown on glucose-supplemented medium produced a high yield of a glycolipid fraction (m.p. 65-70 degrees C and [alpha]25D = + 31.4 degrees), identified as 6-(C40-C46) nocardomycoloylglucose. It accounted for approx. 3.4% of the cell dry wt. and 41% of the diethyl ether soluble lipids obtained from ethanol-diethyl ether extract. Dimycoloyltrehalose (cord factor) was found in a very small amount (0.11%).

Chromatography↗
PubMed1985

Comparative studies of lipopolysaccharide and exopolysaccharide from a virulent strain of Pseudomonas solanacearum and from three avirulent mutants.

The composition of the Pseudomonas solanacearum lipolysaccharide (LPS) was found to be similar to that described for the LPS of enterobacteria. The lipid A contained fatty acids and glucosamine in a molar ratio of 5:2. The LPS fraction contained 2-keto-3-deoxyoctulosonic acid, L-glycero-D-mannoheptose, hexoses (glucose, rhamnose, and glucosamine), and a pentose (xylose). The LPSs from the wild-type strain (GMI1000), from the spontaneous rough mutant (GMI2000), and from their respective acridine orange-resistant (Acrr) mutants (GMI1178 and GMI2179) contained the same component sugars in their polysaccharide moieties, but the relative amounts of each sugar varied greatly. Spontaneous mutation to the rough type was characterized by a decrease in the ratio of rhamnose to glucose, whereas a reverse effect was seen for the acridine orange resistance mutation from the parent strains (GMI1000 and GMI2000) to the respective mutant strains (GMI1178 and GMI2179). The exopolysaccharide (EPS) from GMI1000 was found to be composed of two fractions: a heteropolysaccharide (galactosamine, glucose, and rhamnose) excluded from Sephadex G-50 and an additional glucan with a lower molecular weight. Strains GMI1000 and GMI1178 produced comparable amounts of EPS, GMI2179 synthesized less EPS, and GMI2000 produced no detectable EPS. High-pressure liquid chromatography and 13C nuclear magnetic resonance analyses revealed some differences between these EPSs. The glucan fraction seemed to be the major component of the EPS from GMI2179, whereas GMI1000 and GMI1178 EPSs contained both fractions and appeared to differ in the structures of their heteropolysaccharide fractions. Viscosity measurements confirmed differences between whole EPSs produced by the three strains.

Fatty Acids↗
PubMed1982

[Chemical composition of the Pseudomonas solanecearum lipopolysaccharide].

The structure of Pseudomonas solanacearum lipopolysaccharide is similar to those described for the LPS of enterobacteria. The lipid A contains fatty acids and glucosamine (5 fatty acids for 2 glucosamine residues). The polysaccharide part contains 2-keto-3-deoxy-octulosonate, L-glycero-D-mannoheptose, hexoses (glucose, rhamnose, glucosamine) and a pentose (xylose). Part of 3-hydroxy-myristic acid and the whole 2-hydroxy-octadecenoïc acid are linked to the glucosamine residue by an amide bond.

Carbohydrates↗
PubMed1980

Fatty acid composition of the lipids of Pseudomonas mildenbergii. Presence of a fatty acid containing two conjugated double bonds.

The whole cell fatty acids of Pseudomonas mildenbergii were extracted and separated, as methyl esters, into non-hydroxylated (60.6%) and hydroxylated (39.4%) esters. The main component of the hydroxy-ester fraction was methyl 3D-hydroxydecanoate. The non-hydroxylated fraction mainly consisted of methyl 2-decenoate, the methyl ester of a C-12 acid having two conjugated double bonds, methyl palmitate, methyl methylene-hexadecanoate and methyl vaccenate.

Chemical Phenomena↗
PubMed1976

Glycolipids of brevibacterium vitarumen.

Corynomycolic acids have been identified in the lipids of Brevibacterium vitarumen. The analogy between this strain and typical aerobic Corynebacteria is borne out by these complex lipids, corynomycolic acid being linked as 6,6'-dicorynomycoloyl-trehalose (cord-factor structure) and as 6-monocorynomycoloyl-trehalose.

Brevibacterium↗
PubMed1976

A study on the receptor for a mycobacteriophage : phage phlei.

From Mycobacterium phlei, glycolipid fractions have been isolated which inactivate phage Phlei. On the basis of the characteristics of the inactivation (specificity, kinetics, requirement for Ca++) typical of the phage-host cell system, it was concluded that these fractions contain the receptor sites for phage Phlei ; this conclusion was supported by electron microscopic studies. All the active fractions contain four kinds of components : fatty acids, glycerol, sugars (D-lyxose, 6-0-methyl-D-glucose, and low amounts of glucose and mannose), and water-soluble acids. These acids are isolated by degradation of the receptor fractions as oxalic and pyruvic acids. Variations of the ratio oxalic acid/pyruvic acid according to the mode of degradation and the absence of the peak characteristic of the protons of a pyruvic acid residue in the NMR spectrum, suggest that these acids might arise from the splitting of oxaloacetic acid. A tentative structure of the receptor is proposed, in many monoglycerides are linked through keto-acid to a polysaccharide core.

Binding Sites↗
PubMed1976

Immunization by an insoluble fraction extracted from Brucella melitensis: immunological and chemical characterization of the active substances.

A peptidoglycan-containing fraction called fraction P.I. (phenol insoluble), extracted from Brucella melitensis and previously described by some of us, had immunogenic and protective properties and did not produce any allergic reactions. Since it is well known that bacterial peptidoglycans studied so far have immunoadjuvant properties, the isolation of the active factor(s) of Brucella was undertaken. By successive enzymatic and chemical treatments, a new, much more purified fraction, called "4A" (approximately 5% of fraction P.I.), is obtained, retaining the same properties as P.I. and giving better protection against infection by Brucella. Immunogenicity, immunoadjuvant activity, allergizing capacity, and specific and nonspecific protective effects of fractions P.I. and 4A are compared. Chemically, fraction 4A is constituted by a lipoprotein covalently linked to peptidoglycan and by a few (lipo)proteins that could be solubilized by hot sodium dodecyl sulfate. Intrinsic properties of peptidoglycan could not be studied, but it does not seem to be essential for the activity. In conclusion, fractions P.I. and 4A are not agglutinogenic and, since fraction 4A induces better protection against infection by Brucella, it could advantageously replace fraction P.I. as a vaccine for humans.

Agglutination Tests↗
PubMed1974

A synthetic glycolipid with B-cell mitogenic activity.

A synthetic glycolipid, N-palmitoyl-D-glucosamine, (NPG) was found to be a potent B-cell mitogen, that stimulated spleen cells from nu/nu as well as from normal mice. The proper dispersion of the water insoluble preparation is critical for the elicitation of this mitogenic effect. Limulus lysate clotting assay indicated that the NPG preparation either contains only 0.001% endotoxin contamination, or that NPG itself is 10(-5) times less active in this assay than purified endotoxic LPS. Since such low levels of endotoxin concentration are not mitogenic, it is concluded that synthetic N-palmitoyl-D-glucosamine, when properly dispersed, is itself a B-cell mitogen.

Animals↗