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PubMed1989

Antibodies to Escherichia coli J5 core glycolipids in gnotobiotic and conventionally reared piglets.

Antibody titers to Escherichia coli J5 endotoxin core glycolipids were determined in 5-week-old, unvaccinated, conventionally reared and gnotobiotic pigs in a micro-ELISA. Both groups of pigs had naturally occurring antibody of all major isotypes. The conventionally reared pigs had significantly (P less than 0.05) more serum antibody to J5 endotoxin glycolipids (geometric mean titer, GMT = 2.07) than gnotobiotes (GMT = 0.85). This relationship was not necessarily true in fluids from various anatomical structures. In gnotobiotes, mucosal-associated, anti-J5 glycolipid immunoglobulin was primarily IgM. In conventionally reared piglets, the mucosal-associated, anti-J5 glycolipid antibody contained more IgA. Such naturally occurring antibody could confer partial to complete immunity from challenge with Gram-negative bacteria.

Animals↗
PubMed2004

Structural and serological characterization of the major glycolipid from Rothia mucilaginosa.

Structural studies on the major glycolipid isolated from Rothia mucilaginosa were carried out utilising specific chemical degradation, NMR spectroscopy and matrix-assisted laser-desorption/ionization time of flight mass spectrometry (MALDI TOF-MS). The glycolipid was found to be a dimannosylacylmonoglyceride in which the carbohydrate part was the glycerol-linked dimannoside alpha-D-Manp-(1-->3)-alpha-D-Manp-(1-->3)-sn-Gro (Man A-Man B-Gro), of which Man B was esterified at O-6 by a fatty acid residue. A second fatty acid substituted the secondary methylene position of the glycerol residue, in contrast to the glycolipid previously found in R. dentocariosa and Saccharopolyspora strains, in which the second fatty acid esterified the primary methylene position of glycerol. Results of the ELISA experiment with rabbit specific antibacterial sera indicate that these two major glycolipids are antigenic, and the patterns of serological reactivity are similar but not identical.

Animals↗
PubMed2004

Inhibition of glycolipid biosynthesis by N-(5-adamantane-1-yl-methoxy-pentyl)-deoxynojirimycin protects against the inflammatory response in hapten-induced colitis.

Since glycolipid biosynthesis is potentially involved in immunological and inflammatory responses, we tested the effect of a novel inhibitor of intracellular glycolipid biosynthesis N-(5-adamantane-1-yl-methoxy-pentyl)-deoxynojirimycin (AMP-DNM) in two hapten-induced colitis models: trinitrobenzene sulphonic acid (TNBS)- and oxazolone (4-ethoxymethylene-2phenyl-2oxazoline-5-one; Oxa)-induced colitis. AMP-DNM was given either by intraperitoneal injection or orally via the diet. Mice treated with AMP-DNM had less severe colitis and a more rapid weight recovery, less edema and less wall thickness. Cellular infiltration, goblet cell loss and myeloperoxidase (MPO) activity were reduced in colons of AMP-DNM-treated animals. Intralesional IFN-gamma and IL-18 production were lower in mice of the AMP-DNM-treated groups. Furthermore, AMP-DNM treatment reduced the serum anti-TNBS and anti-Oxa antibody levels. Our findings show that the glycolipid biosynthesis inhibitor AMP-DNM has a strong anti-inflammatory and immune suppressive activity on both TNBS- and Oxa-induced colitis. The data also provide evidence that glycolipid biosynthesis is involved in the inflammatory cascade in these inflammatory bowel disease (IBD) models.

1-Deoxynojirimycin↗
PubMed2005

Effects of DNA polymerase inhibitory and antitumor activities of lipase-hydrolyzed glycolipid fractions from spinach.

We succeeded in purifying the major glycolipid fraction in the class of sulfoquinovosyl diacylglycerol, monogalactosyl diacylglycerol and digalactosyl diacylglycerol (DGDG) from a green vegetable, spinach (Spinacia oleracea L.). This glycolipid fraction was an inhibitor of DNA polymerases and a growth inhibitor of NUGC-3 human gastric cancer cells, and, interestingly, the activities were much stronger when the fraction was hydrolyzed by lipase. Glycolipids in the hydrolyzed fraction consisted of sulfoquinovosyl monoacylglycerol (SQMG), monogalactosyl monoacylglycerol (MGMG) and DGDG. In the in vivo antitumor assay using Greene's melanoma, the fraction containing SQMG, MGMG and DGDG showed to be a promising suppressor of solid tumors. Spinach glycolipid fraction might be a potent antitumor compound if directly injected into a tumor-carrying body, and this fraction may be a healthy food material that has antitumor activity.

Animals↗
PubMed1975

Determination of position of substitution on 2-acetamido-2-deoxy-D-galactosyl residues in glycolipids.

The substitution site on 2-acetamido-2-deoxy-D-galactosyl residues in oligosaccharide chains of glycolipids was determined by permethylation of the glycolipid with methyl iodide in the presence of dimethylsulfinyl carbanion, methanolysis of the permethylated product under mild conditions, acetylation with acetic anhydride-pyridine, and identification of the resulting substituted methyl glycosides of 2-deoxy-2(N-methylacetamido)-D-galactose by g.l.c. The method was applied to glycolipids of known structure, including normal brain ganglioside, Tay-Sachs ganglioside, and Forssman glycolipid.

Acetylgalactosamine↗
PubMed1996

Synthesis of glycolipids containing disaccharides and two longer alkyl chains and their applications as enzyme modifiers.

The aminolysis between p-(aminomethyl)benzoic acid and lactobiono-1,5-lactone was carried out in Me2SO in quantitative yield. The amide formed thus was used directly for the final reaction without isolation of the intermediate from the reaction mixture. This simple one-pot procedure finished a convenient and useful synthesis of the target N-[p-(dialkyl-L-glutamatecarbonyl)-benzyl]lactobionamides. The phase-transition temperature of glycolipids was shown to greatly depend on the structure between the hydrophilic moiety and the hydrophobic segment of the glycolipids. The yield of proteins of lipases coated with the glycolipids containing disaccharides remarkably increased with alkyl-chain length, which was higher than that with glycolipids containing monosaccharides. The yields were also closely correlated to the origin of the lipases. The enzymatic reactivity of lipid-coated lipase PS was seldom affected by the hydrophobic segment of lipids, but its enantioselectivity was mainly affected by the hydrophilic moiety of lipids.

Amides↗
PubMed2001

An ELISA for five glycolipids from the cell wall of Mycobacterium tuberculosis: Tween 20 interference in the assay.

Mycobacterium tuberculosis cell wall contains antigenic glycolipids: phenol-glycolipid (PGL), diacyltrehalose (DAT), triacyltrehalose (TAT), cord-factor (CF), and sulpholipid-I (SL-I). In the last decade, the usefulness of these antigens for the serodiagnosis of tuberculosis has been evaluated mainly using enzyme-linked immunosorbent assays (ELISA). Currently, there are no conclusive results about the utility of these glycolipidic antigens, because the results obtained by different groups are discrepant. In order to explain these discrepancies, we have investigated the methodological variations in the ELISAs used previously. Specifically, we have studied the following: the coating solvent, the optimum amount of glycolipid coated per well, the blocking agent, and the use of detergent (Tween 20) in the washing buffer. The most significant finding was that Tween 20 detaches PGL, DAT, TAT and SL-I from microtitre wells. However, Tween 20 does not remove CF from the wells. In addition, we have found that the best solvent for coating is n-hexane, that the optimum antigen coating concentration is 1000 ng/well, and that BSA and gelatin are equally effective blocking agents. We can therefore conclude that the use of Tween 20 as a detergent, and the lower antigen coating concentrations (100-200 ng/well), may well explain some of the discrepancies in previous studies.

Antibodies, Bacterial↗
PubMed2006

Identification and analysis of novel glycolipids in vertebrate brains by HPLC/mass spectrometry.

Glycosphingolipids are a major component of microdomains or lipid rafts in biological membranes. A new member of raft glycolipids, phosphatidylglucoside (PtdGlc), as well as 6-O-Ac-PtdGlc, a form of PtdGlc O-acetylated at position 6 of its glucopyranose ring, is present in central nervous system tissues. Because the glycolipids represent a minor constituent of lipid rafts and because their mass numbers are the same as that of phosphatidylinositol (PI), the glycolipids are difficult to detect and purify. Here we describe methods to purify and identify glycolipids from rodent brain and methods to discriminate PtdGlc from PI in chick spinal cord using HPLC/electrospray ionization ion-trap mass spectrometry.

Animals↗
PubMed2002

Structure and antigenicity of the major glycolipid from Taenia solium cysticerci.

Lipids were extracted from cysticerci of the human tapeworm Taenia solium isolated from various infected pigs and analysed by two-dimensional thin-layer chromatography. These consisted of both alkali-labile and alkali-stable glycolipids, and phosphorylated non-glycosylated lipids. Because abundant and immunogenic glycolipids of parasites have been implicated in host-parasite interactions, the major lipid, an alkali-stable glycolipid, was purified by chromatography and its structure and antigenicity were determined. The structure of the major glycolipid of T. solium, GSL-I, was elucidated through a combination of chemical degradative methods, gas chromatography/mass spectrometry analyses of the degradative products, matrix-assisted-laser desorption/ionisation time of flight mass spectrometry and nuclear magnetic resonance spectroscopy. This analytical strategy led to the identification of a family of beta-galactosylceramides composed mainly of phytosphinganine (2-hydroxylated sphinganine) N-acylated by C16-C24 fatty acids, with the predominance of 2-hydroxylated homologues. Enzyme-linked immunosorbent assay showed no correlation between the antibody titres directed against GSL-I in the human sera and the infective status; in contrast, a very high specific immunoreactivity and a sensitivity above 50% were observed when GSL-I was tested with cerebrospinal fluids from well characterised infected humans. Thus, although these results do not support the use of GSL-I alone as an antigen for the detection of neurocysticercosis, its use as part of an antigen cocktail for the diagnosis of the disease in cerebrospinal fluids merits further investigations.

Animals↗
PubMed1999

Multi-enzyme kinetic analysis of glycolipid biosynthesis.

Gangliosides are acidic glycosphingolipids synthesized sequentially by a series of glycosyltransferases acting in parallel biosynthetic pathways. While most glycosyltransferases are highly specific, some, however, may catalyze equivalent steps in each pathway using different gangliosides as substrates (e.g. N-acetylgalactosaminyltransferase, sialyltransferase-IV). A multi-enzyme kinetic analysis was developed on the condition that serial enzymatic reactions operate below substrate saturation. A multi-enzyme kinetic analysis enabled a simultaneous calculation of the Vmax/Km value of each enzyme derived from the equilibrium concentration of the respective substrate. Substrate concentrations [S] were determined by radioactive labelling of gangliosides in intact cells with the precursor sugars [14C]galactose and [14C]glucosamine, followed by high-performance thin-layer chromatography and autoradiography of the radiolabelled glycolipids. On the basis of Michaelis-Menten kinetics, Vmax/Km values were derived from [S] by a system of linear equations. The procedure was used to analyze the development of the glycolipid composition during differentiation of rat gliomaxmurine neuroblastoma (NG108-15) cells. The Vmax/Km values calculated by multi-enzyme kinetic analysis were consistent with the kinetic data obtained with solubilized enzymes. Application of multi-enzyme kinetic analysis to published data on the correlation of enzyme activities with ganglioside levels in various cell lines and tissues indicated the validity of this method for analysis of the glycolipid biosynthesis, in particular, of its initial steps. On the basis of the kinetic analysis, it is suggested that the cell lines can be divided into two groups with respect to the substrate pools of GM3 used by sialyltransferase-II and N-acetylgalactosaminyltransferase-I. The first group encompasses the majority of the neuroblastoma cell lines and the embryonic rat brain where the two enzymes share a common pool of GM3. In the second group, the two enzymes do not compete for the same pool of GM3, indicating a different subcellular localization of CMP-NeuAc:GM3 alpha2-8-sialyltransferase and UDP-N-acetylgalactosaminyl:GM3 N-acetylgalactosaminyltransferase. In this study, the theory of a multi-enzyme kinetic analysis is discussed and its application to analysis of the glycolipid biosynthesis in neuroblastoma cells is demonstrated. A multi-enzyme kinetic analysis can be applied to other biosynthetic pathways and provides the advantage of analyzing kinetic data with intact cells or tissue samples.

Animals↗
PubMed1993

Thin-layer chromatographic analysis of glycolipids and mycolic acids from Mycobacterium farcinogenes, Mycobacterium senegalense and related taxa.

Seventy-nine representative strains of Mycobacterium farcinogenes, Mycobacterium fortuitum, Mycobacterium peregrinum and Mycobacterium senegalense were analysed by thin-layer chromatography for diagnostic glycolipid and mycolic acid patterns. On the basis of glycolipid patterns the 16 M. senegalense strains were assigned to four groups (I, II, III and IV); one strain received as M. farcinogenes had glycolipids that corresponded to those given by the M. senegalense group III strain. Representatives of M. fortuitum produced alkalilabile glycolipids whereas the M. peregrinum strains produced alkali-stable glycopeptidolipids related to those of M. senegalense group I. Members of M. senegalense groups I, III and IV and the M. farcinogenes strains gave the characteristic pattern consisting of alpha- and epoxymycolates on thin-layer chromatographic analysis of the products of alkaline hydrolysis with 5% aqueous tetrabutylammonium hydroxide. Extraction of mycolates from the same strains using acid methanolysis revealed alpha-mycolates and characteristic more polar long-chain components originating from epoxymycolates. In contrast, the M. senegalense group II strains contained an additional more polar omega-1 methoxymycolate that was detected from both acid and alkaline hydrolysates; this spot was also seen in some M. fortuitum and M. peregrinum strains. Preliminary investigations, using a combination of thin-layer chromatography and immunostaining, showed that glycopeptidolipids from M. peregrinum and M. senegalense group I strains were antigenic, a cross-reaction between members of these taxa was shown. In contrast, no reaction was detected between glycopeptidolipids extracted from M. peregrinum and M. senegalense group I strains with antisera from either M. farcinogenes or M. fortuitum.

Animals↗
PubMed1997

Myelin glycolipids and their functions.

During myelination, oligodendrocytes in the CNS and Schwann cells in the PNS synthesise myelin-specific proteins and lipids for the assembly of the axon myelin sheath. A dominant class of lipids in the myelin bilayer are the glycolipids, which include galactocerebroside (GalC), galactosulfatide (sGalC) and galactodiglyceride (GalDG). A promising approach for unravelling the roles played by various lipids in the myelin membrane involves knocking out the genes encoding important enzymes in lipid biosynthesis. The recent ablation of the ceramide galactosyltransferase ( cgt) gene in mice is the first example. The cgt gene encodes a key enzyme in glycolipid biosynthesis. Its absence causes glycolipid deficiency in the lipid bilayer, breakdown of axon insulation and loss of saltatory conduction. Additional knock-out studies should provide important insights into the various functions of glycolipids in myelinogenesis and myelin structure.

Animals↗
PubMed2003

ATP leakage from yeast cells treated by extracellular glycolipids of Pseudozyma fusiformata.

The ustilaginaceous yeast Pseudozyma fusiformata secreted glycolipids which were lethal to many yeasts and fungi more active at pH of about 4.0, and in the temperature range of 20-30 degrees C. Purified glycolipids enhanced non-specific permeability of the cytoplasmic membrane in sensitive cells, which resulted in ATP leakage and susceptibility of the cells to staining with bromocresol purple. Cells of Saccharomyces cerevisiae lost the ability to acidify the medium. Basidiomycetous yeasts were more sensitive to the glycolipids than ascomycetous ones. The minimal effective glycolipid concentration was 0.13 and 0.26 mg ml(-1) for Cryptococcus terreus and Filobasidiella neoformans, while for Candida albicans and Saccharomyces cerevisiae it was 1.0 and 1.6 mg ml(-1).

Adenosine Triphosphate↗
PubMed1989

Plasma desorption mass spectrometric analysis of mycobacterial glycolipids.

Mycobacteria are characterized by species- or type-specific glycolipid antigens. These are generally of the following three types: the trehalose-containing, acylated lipooligosaccharides (LOS), the C-mycoside glycopeptidolipids (GPL), and the phenolic glycolipids (PGL). To date, convenient mass spectrometric analysis of the intact form of these complex glycolipids has proved to be difficult. The successful plasma desorption mass spectrometric analysis of intact mycobacterial glycolipids of the LOS, GPL, and PGL types is now reported, allowing location of the acyl residues and providing oligosaccharide sequence and molecular weight information.

Chemical Phenomena↗
PubMed1991

Structural elucidation and antigenicity of a novel phenolic glycolipid antigen from Mycobacterium haemophilum.

The structure of a novel antigenic glycolipid that distinguishes the opportunistic pathogen Mycobacterium haemophilum from all other mycobacteria was established by a series of degradation reactions leading to products that were analyzed by gas/liquid chromatography-mass spectrometry. The complete structure of the oligosaccharide unit was determined as 2,3-di-O-CH3-alpha-L-Rhap(1----2)3-O-CH3-alpha-L-Rhap(1----4 )-2,3-di-O-CH3-alpha-L-Rhap(1----. The lipid portion of the phenolic glycolipid was composed of two component phenolphthiocerols differing by two methylene groups, as determined by analysis of their per-O-trideuteriomethylated derivatives. The diol unit of the phenolphthiocerols has a threo relative configuration. The absolute stereochemistry of the asymmetric centers of the phenolphthiocerols is uncertain, but the centers are probably 3R, 4S, 9R, and 11R as found for phthiocerol A from Mycobacterium tuberculosis. The hydroxyl functions of the branched glycolic chain are esterified to a complex mixture of multi-methyl branched mycocerosic acids, C27, C30, C32, C34, and C37 with molecular weights (as methyl esters) of 424, 466, 494, 522, and 564, respectively. The stereochemistry of the methyl branches of the mycocerosates have R absolute configuration. The glycolipid is highly antigenic and appears to be specific for M. haemophilum. There are intriguing similarities between the product from M. haemophilum and the well-known phenolic glycolipid I of Mycobacterium leprae, a matter that is discussed.

Animals↗
PubMed1989

Glycolipid glycosyltransferases in human embryonal carcinoma cells during retinoic acid induced differentiation.

Retinoic acid induced differentiation of TERA-2-derived human embryonal carcinoma cells is accompanied by a dramatic reduction of extended globo-series glycolipids, including galactosyl globoside, sialylgalactosyl globoside, and globo-A antigen (each recognized by specific MoAbs). Associated with these glycolipid changes, the activities of two key enzymes, alpha 1----4 galactosyltransferase (for synthesis of globotriaosyl core structure) and beta 1----3 galactosyltransferase (for synthesis of galactosyl globoside), were found to be reduced 3- to 4-fold. The latter enzyme plays a key role in the synthesis of extended globo-series structures, and its characterization has not been reported previously. Therefore, its catalytic activity was studied in detail, including substrate specificity, detergent and phospholipid effects, pH and cation requirements, and apparent Km. During retinoic acid induced differentiation, a series of Lex glycolipid antigens (recognized by anti-SSEA-1 antibody) and their core structures (lacto-series type 2 chains) increase dramatically. In parallel with these changes in glycolipid expression, the activities of two key enzymes, beta 1----3 N-acetylglucosaminyltransferase (for extension of lacto-series type 2 chain) and alpha 1----3 fucosyltransferase (for synthesis of Lex structure), were found to increase by 4- and 2-fold, respectively. Similarly, an increase in the expression of several gangliosides (e.g., GD3 and GT3) during retinoic acid induced differentiation was mirrored by a 4-fold increase in the activity of alpha 2----3 sialyltransferase (for synthesis of ganglio core structure, GM3). The results suggest a coordinate regulation of key glycosyltransferases involved in core structure assembly and terminal chain modification.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Structure elucidation of marker glycolipids of alloantigen-activated murine T lymphocytes.

DBA/2 mouse spleen cells were stimulated in vitro by (a) alloantigen (mitomycin-treated CBA/J splenocytes), (b) the T cell mitogen concanavalin A (Con A), and (c) the B cell mitogen lipopolysaccharide (LPS). The cultures were pulsed for 10 h with (14)C-labeled galactose and glucosamine. Radiolabeled glycosphingolipids (GSL's) were extracted from the cells and the neutral GSL's isolated and analyzed by high-performance thin-layer chromatography. Two of the radioactive neutral GSL's, 9 and 12a, were found to be prominent in the alloantigen-stimulated cells but not in T cells stimulated by Con A. GSL 9 was also present as a minor component in LPS-stimulated B lymphocytes. GSL's 9 and 12a were purified by preparative column chromatography on Iatrobeads. The sequence and anomeric linkages of the carbohydrate moiety of these glycolipids were determined by successive degradation with exoglycosidases. The structures were shown to be Gal(alpha1-x)Gal(beta1-x)GlcCer (glycolipid 9) and GalNAc(beta1-x)Gal(alpha1-x)Gal(beta1-x)GlcCer (glycolipid 12a), respectively. The latter glycolipid may serve as a marker for alloantigen-activated T cell subpopulations.

Animals↗
PubMed1982

Chemical synthesis of alpha-L-fucopyranosylceramide and its analogues and preparation of antibodies directed to this glycolipid.

A novel glycolipid, alpha-L-fucopyranosylceramide, was previously isolated and characterized from metastatic human adenocarcinoma [Watanabe, K., Matsubara, T., & Hakomori, S. (1976) J. Biol. Chem. 251, 2385-2387]. For further investigation of the pathobiological significance of this glycolipid with its specific antibodies, the antigen glycolipid alpha-L-fucopyranosylceramide was chemically synthesized by Königs-Knorr-type condensation of 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide and a ceramide, followed by removal of benzyl groups by catalytic hydrogenation. alpha-L-Fucopyranosyl-N-palmitoylethanolamine and 2,3,4-tri-O-benzyl-alpha-L-fucopyranosylsphingosine were also synthesized. The antibodies prepared against a synthetic alpha-L-fucopyranosyl-ceramide included in liposome reacted very well with the synthetic as well as the natural alpha-L-fucopyranosylceramide isolated from human adenocarcinoma, but the kinetics of the complement-dependent liposome lysis and the complement fixation pattern with the synthetic fucosylceramide were significantly different from those with the natural fucosylceramide. The natural fucosylceramide showed a much weaker immunogenicity than the synthetic fucosylceramide. The remarkable difference in liposome lysis, complement fixation, and immunogenicity between the synthetic and the natural fucosylceramide must be due to the difference in ceramide structures. The results indicate that the strength of antigenicity and immunogenicity of glycolipids may greatly depend on ceramide structure, whereas the specificity is solely determined by the sugar moiety. The anti-alpha-L-fucosylceramide antibodies display cross-reactivity with galactosylceramide, ceramide, and liposome alone that was eliminated by absorption with galactosylceramide liposomes.

Complement Activation↗