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PubMed1985

Analysis of gangliosides using fast atom bombardment mass spectrometry.

The native gangliosides GM3, GM1, Fuc-GM1, GD1a, GD1b, Fuc-GD1b, GT1b and GQ1b were analysed by fast atom bombardment mass spectrometry (FAB-MS) in the negative ion mode in a matrix of thioglycerol. After permethylation the same gangliosides were analysed by electron impact (EI) and FAB-MS in the positive ion mode. The negative ion mass spectra furnished information on the molecular weight, the ceramide moiety and the sequence of carbohydrate residues. The sites of attachment and the number of sialic acids present could be deduced directly from the pattern of sequence ions. After addition of sodium acetate positive ion FAB-spectra of the permethylated samples show intense pseudomolecular ions M + Na, that provide evidence on the homogeneity of the samples. In addition, the ceramide part, the oligosaccharide moiety obtained after cleavage of the glycosidic bond of the hexosamine residue, the whole carbohydrate chain and the sialic acids are represented by specific fragment ions. With EI-MS further information can be obtained on the sphingosine and fatty acid components of the ceramide residue. The data show, that the combination of soft ionization mass spectrometry with classical EI-MS gives valuable information on the structure and homogeneity of gangliosides. The method is also applicable to the structural elucidation or quantitation of more complex gangliosides or glycolipid mixtures using only micrograms of material.

Animals↗
PubMedDate not supplied

Light scattering measurements on gangliosides: dependence of micellar properties on molecular structure and temperature.

Static and dynamic laser light scattering measurements on micellar aqueous solutions of gangliosides GM2, GM1, GD1a are reported. The aggregation number, the hydrodynamic radius and the micellar shape depend on the type of ganglioside and the unsaturation degree of the hydrocarbon chains. At a temperature of 25 degrees C the molecular weights of GM2, GM1 and GD1a are 740,000, 470,000 and 418,000 DA respectively. A significant decrease of micellar size with temperature has been found for saturated GM1 in the region 25 degrees-40 degrees C. The strong sensitivity of the micellar parameters to the ganglioside structure is explained by making reference to some simple model which takes into account geometrical packing considerations. By measuring the scattered light intensity at low ionic strength of the solution (0.1-30 mE) it was possible to evaluate the ganglioside micellar charge, 100 electronic units for GM2, 48 for GM1 and 60 for GD1a.

Gangliosides↗
PubMed1994

Aggregative properties of gangliosides in solution.

The aggregative properties of gangliosides in diluted aqueous solutions are discussed on the basis of simple and well-established thermodynamic concepts. Theoretical assumptions are compared with experimental data obtained, mainly by scattering techniques, on GM3, GM2, GM1, GD1a, GalNAc-GD1a, GD1b, GD1b lactone and GT1b gangliosides, all containing ceramide portions of similar composition, and on GM1 molecular species containing different well-defined ceramide structures. We also report on mixed aggregates with amphiphilic compounds and on the ganglioside aggregate-soluble protein interaction effects which give rise to very stable lipoproteic complexes of well-defined ganglioside-protein composition.

Carbohydrate Conformation↗
PubMed1994

Synthesis and aggregative properties of GM1 ganglioside (IV3Neu5AcGgOse4Cer) containing D-(+)-2-hydroxystearic acid.

GM1 ganglioside containing a hydroxylated fatty acid moiety, GM1(OH), was synthesized starting from lyso-GM1 and D-(+)-2-hydroxystearic acid. The aggregative, geometrical and distribution properties of GM1(OH) were compared with those of stearic acid containing GM1 ganglioside; laser light scattering measurements, differential scanning calorimetry and fluorescence spectroscopy were used. GM1 and GM1(OH) are present in solution as micelles with a hydrodynamic radius of 58.7 and 60.0 A, and molecular mass of 470 and 570 kDa, respectively. The surface area occupied by the monomer of GM1(OH) at the lipid-water interface of the aggregate was calculated to be 117 A2, which is 3 A2 lower than that determined for GM1. Proton NMR analyses of GM1 and GM1(OH) suggest different three-dimensional structures at the ganglioside lipid-water interface. Both GM1(OH) and GM1 inserted into dipalmitoylphosphatidylcholine (DPPC) vesicles undergo segregation phenomena, with the formation of ganglioside-enriched microdomains, but GM1(OH) shows a higher degree of dispersion in the DPPC matrix and exerts a lower rigidifying effect than does GM1.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

Observation of ganglioside lactone formation with CD spectrometry.

Monolactone (NeuAc1-9NeuAc linkage) formation of a ganglioside, GD1b, was observed at 20 degrees C on solutions ranging in concentration from 0.008 to 1.7 mM and in pH from 2 to 8.1, by following the change of ellipicity at 235 nm, where lactonized gangliosides showed a strong Cotton effect. The lactonization was found to be a first-order reaction in both GD1b and H+ in the initial stage but was affected later by a backward reaction, hydrolysis of the lactone linkage. The rate constant was 0.08 h-1 at pH 3. At this pH the reaction went close to equilibrium in 24 h at approximately 70% lactonization. At pH higher than 5.9 no change was observed in the ellipticity within 30 h, suggesting the possibility that at most 0.6% of the ganglioside lactonized. Lactonization of another ganglioside, GD3, in glacial acetic acid was observed with a 0.2-mm cell, agreeing well with a reported result.

Animals↗
PubMed1995

Ganglioside GD1a generates domains of high curvature in phosphatidylethanolamine liposomes as determined by solid state 31P-NMR spectroscopy.

We have studied the effects of gangliosides on the polymorphic behaviour of phosphatidylethanolamines. The ganglioside GD1a promotes the formation of phases which give rise to isotropic 31P-NMR resonance lines, particularly in the temperature range of the L alpha to HII transition. In addition, higher mol fractions of ganglioside raise the L alpha to HII phase transition temperature. Our results demonstrate that small mol fractions of gangliosides can have profound effects on the molecular organization of phosphatidylethanolamines.

Calorimetry, Differential Scanning↗
PubMed1996

Experimental evidence of a temperature-related conformational change of the hydrophilic portion of gangliosides.

The present paper reports the experimental observation of an interesting thermodynamic process which could be biologically important: such behaviour, shown by some gangliosides, is likely to be peculiar of these glycosidic compounds as it has never been observed for other membrane-type amphiphilic molecules. In water solution, gangliosides have been found to present a bistable behaviour between two stable states (called A and B) which does not involve any change in the primary structure of the molecule. The interconversion between state A and state B, and vice versa, does not occur spontaneously, but has to be triggered by some external agent, which makes this system a potentially regulated process with important biological correlations. In the present experiments, state B is reached from state A with a temperature rise in the range 30-55 degrees C. The new state is stable regardless of any possible temperature cycle. The initial state A is then regained when the ganglioside solution is dried and the solute is redissolved. The two states are believed to correspond to two different conformations of the hydrophilic portion of the molecule. The bistable behaviour is shown by the gangliosides GM2, GM1, GD1a, GD1b and Fuc-GD1b, GT1b, however, does not show such an effect.

Animals↗
PubMed1984

Changes in ganglioside metabolism during in vitro differentiation of quail embryo myoblasts.

The metabolism of gangliosides was studied during the in vitro differentiation of both normal quail myoblasts and myoblasts which have been transformed by a temperature-sensitive mutant of Rous sarcoma virus (RSV). These transformed cells can be maintained undifferentiated if incubated at 35 degrees C, but they will differentiate when shifted to 41 degrees C. (D. Montarras and M. Y. Fiszman (1983) J. Biol. Chem. 258, 3882-3888). The analysis of [14C]Glucosamine-labeled gangliosides by two-dimensional thin-layer chromatography reveals variations in the metabolism of the gangliosides during the process of differentiation. During the formation of myotubes, it was observed that the accumulation of GD1a is reduced, while the accumulation of GD3 is increased. Therefore, this results in the variation of the ratio GD3/GD1a which increases from 1.8 to 25 in the case of clones of transformed myoblasts, and from 0.5 to 1.7 in the case of uninfected myoblasts. These variations which have been observed seem to be specific of the myogenic differentiation since they cannot be reproduced when differentiation is inhibited by BUdR treatment or when fibroblasts reach confluency and are blocked in the G1 phase of cell cycle. Furthermore, the transformed myoblasts in vitro are shown to be a good model system since their gangliosides composition is very similar to that of muscle cells in vivo.

Animals↗
PubMed1987

The improved efficient method for introducing macromolecules into cells using HVJ (Sendai virus) liposomes with gangliosides.

Macromolecules such as DNA and RNA can be entrapped within liposomes associated with gangliosides by reverse-phase evaporation. When these liposomes are incubated with HVJ2 (Sendai virus), they deliver their contents into cultured cells efficiently. More than 95% cells of a Ltk- cell line (thymidine kinase-deficient cells) transiently expressed thymidine kinase activity by thymidine kinase gene transfer using HVJ liposomes with gangliosides. Stable transformants could be obtained efficiently from various cell lines by use of HVJ liposomes containing the neoR gene. The neo+ transformants were obtained at frequencies of about 0.2-1.0, 0.06-0.25, and 0.06-0.1% in monolayers of L, CHO-Kl, and HeLa-S3 cells, respectively. Moreover, in Ehrlich ascites tumor cells which grow in suspension, the frequency was more than 0.01%. On introduction of plasmid pTK4 into Ltk- cells, about 0.5-1.0% TK+ transformants were obtained. Cosmid DNA containing the neoR gene (about 45 kbp) was also introduced into L cells by this method and neo+ transformants were obtained at a frequency of 0.1%. When rat liver mRNA was introduced into L cells by HVJ liposomes with gangliosides, immunoprecipitation studies showed that the L cells secreted rat albumin and some other proteins into the cultured medium. Moreover, using erythrocyte membrane vesicles containing IgM that had been incubated with HVJ empty liposomes with gangliosides, the IgM could be introduced into all the L cells.

DNA↗
PubMed1994

Exposure to galactose oxidase of GM1 ganglioside molecular species embedded into phospholipid vesicles.

The exposure of GM1 molecular species present in the native ganglioside, carrying C18:1 or C20:1 long-chain bases (LCB), to Dactylium dendroides galactose oxidase was studied. When native GM1 (49.3% C18:1 and 50.7% C20:1 LCB, respectively), was inserted in dipalmitoylphosphatidylcholine vesicles and partially oxidized (10%), the proportion of C18:1 and C20:1 species in the oxidized GM1 was 59.6% and 40.4%, respectively, suggesting a preferential action of the enzyme on the shorter species. The Vmax of the enzyme was higher on C18:1 GM1 than on C20:1 GM1. The molecular species were affected without any preference after partial (10%) oxidation of GM1 incorporated in egg phosphatidylcholine vesicles or in micellar form. These data indicate that the exposure of the terminal galactose moiety of GM1 ganglioside to galactose oxidase is affected by the ganglioside ceramide composition as well as the phospholipid environment, that presumably determine the distribution (molecular dispersion, segregation) of the ganglioside within the membrane.

Animals↗
PubMed1994

Ganglioside antigen of DU-PAN-2 in a human pancreatic cancer.

DU-PAN-2 reactive gangliosides were isolated from the tumor of a patient with pancreatic cancer (duct cell carcinoma, moderately differentiated adenocarcinoma), having a negative Lewis blood phenotype, and were analyzed by means of TLC-immunostaining, enzyme-linked immunosorbent assay (ELISA), permethylation study, 1H NMR spectroscopy and fast atom bombardment mass spectrometry. The structures of the gangliosides were found to be NeuAc alpha 2-3Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1'Cer, containing normal and hydroxy fatty acids. By TLC-immunostaining and ELISA with chemically synthesized gangliosides, DU-PAN-2 was demonstrated to react strongly with IV3 alpha NeuAc-Lc4Cer, weakly with IV3 alpha NeuAc-nLc4Cer, and moderately with IV6 alpha NeuAc-Lc4Cer and IV6 alpha NeuAc-nLc4Cer. Thus it was concluded that the DU-PAN-2 reactive ganglioside in the tumor is IV3 alpha NeuAc-Lc4Cer and that DU-PAN-2 has a rather broad specificity.

Aged↗
PubMed1995

Influence of extracellular matrices on ganglioside pattern of two hepatoma cell lines with different adhesive properties.

A cell culture model was developed to investigate the involvement of gangliosides in cell-matrix adhesion. Two cell lines with different adhesive properties derived from solid Morris hepatoma 7777 were established. Cultured in horse serum-containing medium, the adhesive cell line (MH 7777A) adheres and spreads on uncoated culture dishes, whereas the revertant cell line (MH 7777A > N) does not adhere and grows in suspension. The adhesiveness of both cell lines is dependent on the coating protein used (none, bovine serum albumin, fibronectin or collagen I) and the horse serum concentration in the culture medium. Both cell lines, although of the same origin, differed in their ganglioside composition. The most abundant ganglioside of both MH 7777A and MH 7777A > N cell lines was fucosyl-GM1, 0.78 and 0.72 microgram per mg cellular protein, respectively. The GM3 and GD1a content of MH 7777A > N cells was significantly higher than that of MH 7777A cells. Furthermore, a matrix-dependency of the ganglioside pattern of both cell lines was demonstrated.

Animals↗
PubMed1993

Separation of gangliosides using cyclodextrin in capillary zone electrophoresis.

Gangliosides are glycosphingolipids containing sialic acid. These glycolipids have been suggested to play important roles in biological processes such as cell growth, differentiation and malignant transformation. Based on these proposed biological functions, gangliosides can be used as diagnostic tools and therapeutics for various human diseases. In this study, capillary zone electrophoresis (CZE) was used to determine the major gangliosides GM1, GD1a, GD1b and GT1b in mammalian brains, in addition to GM3 and Lac. Enhancement of selectivity and efficiency of separation was obtained by using 50 mM borate-phosphate buffer containing 16.5 mM alpha-cyclodextrin (alpha-CD). Under this condition, several forms of gangliosides were successfully separated from extracts of deer antler, apricot seed and rat brain. The results demonstrate that the CD-modified CZE is a useful method for detecting glycolipids from various biological matrices.

Animals↗
PubMed1995

Capillary electrophoresis of carboxylated carbohydrates. I. Selective precolumn derivatization of gangliosides with UV absorbing and fluorescent tags.

We demonstrate that the precolumn derivatization reaction, recently introduced by our laboratory for the selective labeling of carboxylated monosaccharides, can be readily transposed to other glycoconjugates containing carboxylated sugar residues, namely sialogangliosides. The selective derivatization reaction described here involved the attachment of sulfanilic acid (a UV-absorbing tag) or 7-aminonaphthalene-1,3-disulfonic acid (a UV-absorbing and also fluorescing tag) to the sialic acid moiety of the gangliosides via the carboxylic group in the presence of water-soluble carbodiimide. This labeling of the sialic acid moiety of the gangliosides with a chromophore and/or fluorophore leads to the formation of an amide bond between the carboxylic group of the sugar residue and the amino group of the derivatizing agent, thus replacing the weak carboxylic acid group of the carbohydrate species by the stronger sulfonic acid group which is ionized over the entire pH range. Furthermore, novel electrolyte systems were introduced and evaluated for the separation of the derivatized and underivatized gangliosides. The addition of acetonitrile or alpha-cyclodextrin (alpha-CD) to the running electrolyte was necessary to break-up the aggregation of amphiphilic gangliosides and allowed for their efficient separation as monomers in aqueous media using capillary electrophoresis. Several operating parameters were investigated with these electrolyte systems including the additive concentration as well as the ionic strength, pH and nature of the running electrolyte. Acetonitrile at 50% (v/v) in 5 mM sodium phosphate at high and low pH or 15 mM alpha-CD in 100 mM sodium borate, pH 10.0, proved ideal, in terms of resolution and separation efficiency, for the group separation of mono-, di- and trisialogangliosides. On the other hand, the complete resolution of disialoganglioside isomers (e.g., GD1a and GD1b) necessitated the superimposition of a chromatographic component on the electrophoretic process. This was achieved by adding either a hydrophobic (e.g., decanoyl-N-methylglucamide-borate surfactant complex) or hydrophilic [e.g., poly(vinyl alcohol) or hydroxypropyl cellulose] selectors to the running electrolyte.

Animals↗
PubMed1985

Direct sensitive immunocharacterization of gangliosides on plastic thin-layer plates using peroxidase staining.

A technique for the immunocharacterization of gangliosides on thin-layer plates using a peroxidase-labelled anti-Ig antibody is described. The technique uses plastic plates and does not necessitate any transfer of the antigen onto nitrocellulose for immunodetection. Being extremely sensitive, it permits the characterization of gangliosides which cannot be detected by classical densitometric techniques and allows the detection of gangliosides even in trace amounts in ganglioside mixtures. It appears to be useful for the screening of monoclonal antibodies because of its rapidity. Its specificity was found to be analogous to other immunological techniques such as complement fixation and agglutination.

Antibody Specificity↗
PubMed1977

VCN-releasable sialic acid and gangliosides in human neuroblastomas.

The ganglioside pattern and VCN-releasable sialic acid residues of six human neuroblastomas were studied. There was no correlation between VCN-releasable sialic acid and prognosis. The ganglioside patterns were more complex in those cases with an expected good prognosis as reflected by the presence of trisialoganglioside. The complexity of the ganglioside pattern did not always correlate with the histologic grade of the tumor. These results suggest the ganglioside pattern may serve as a chemical marker for predicting the prognosis in patients with neuroblastomas.

Abdominal Neoplasms↗
PubMed1992

The effect of mixed bovine brain gangliosides on hypoxic conduction block in control and streptozotocin-diabetic rats.

This study describes the electrophysiological responses of endoneurial preparations derived from rat sciatic nerve to acute hypoxia in vitro. Preparations from control rats exhibited a 40% decline in compound action potential (CAP) amplitude after 40 min exposure to medium gassed with 8% O2. In preparations from 4 week streptozotocin-diabetic rats CAP declined by only 29%, indicating a resistance to hypoxic conduction blockade. Treating diabetic rats with mixed bovine brain gangliosides (10 mg/kg/day i.p.) exaggerated this resistance to hypoxic conduction blockade as CAP amplitude fell to only 18% of initial values. In a separate experiment, treating non-diabetic rats with gangliosides (10 mg/kg/day i.p.) or adding gangliosides (400 micrograms/ml) directly to the medium in which control nerves were maintained during in vitro recording also significantly attenuated the decline in CAP amplitude after 40 min hypoxia, thus effectively inducing a resistance to hypoxic conduction blockade similar to that observed in nerves from diabetic rats. These studies demonstrate that the systemic or acute local administration of gangliosides induces a resistance to hypoxic conduction block in normal nerve and exaggerates the resistance to hypoxic conduction block of diabetic rats.

Action Potentials↗
PubMed1992

Gangliosides and sialoglycoproteins in hypothalamus of normal, postnatal, and pre- and postnatal protein undernourished rats.

Total ganglioside and sialoglycoprotein concentrations were determined in the hypothalamus of normal (diet: 25% casein), postnatal undernourished (diet: 8% casein since birth), and pre- and postnatal undernourished rats (diet: 8% casein since pregnancy). Hypothalamic weights for the two low protein diet groups were lower than for the normal diet groups at all ages studied. Total hypothalamic ganglioside and sialoglycoproteins (mumol NANA) of postnatal undernourished rats were lower than control at day 10, while in pre- and postnatal undernourished rats this difference occurred at day 7. The reduction in gangliosides and sialoglycoprotein contents was not solely a consequence of the decrease in hypothalamic weight since, when the data were expressed as nmol NANA/mg tissue, similar reductions were observed principally in the pre- and postnatal protein undernutrition group. These results suggest that the effects of pre- and postnatal undernutrition on hypothalamic gangliosides and sialoglycoproteins are more pronounced than those that occur as a result of postnatal undernutrition.

Aging↗