[Glycosphingolipids of human aorta]. / Glikosfingolipidy aorty cheloveka.

The structures of the main gangliosides of human aorta (intima and media) were elucidated. The main component (67%) was identified as N-acetylneuraminosyl-lactosylceramide (ganglioside GM3). The aorta tissue contained also gangliosides GM1, GD3, GD1a, and GT1. All sialic acid residues in gangliosides were present as N-acetyl-neuraminosyl derivatives. Among neutral glycosphingolipids of human aorta, the main components were identified as glucosylceramide, lactosylceramide, globotriaosylceramide and globotetraosylceramide. The preliminary data suggest that the composition of the investigated glycosphingolipids in tissue might vary upon atherosclerosis lesions of aorta.

[Study of prostaglandins and thromboxanes B2 using mass-spectrometry of secondary ions]. / Issledovanie prostaglandinov i tromboksanov B2 metodom mass-spektrometrii vtorichnykh ionov.

Prostaglandins E, F, I2 and thromboxane B2 have been studied by secondary ion mass spectrometry. It is shown that the method is suitable for direct identification of these compounds either as free acids or as their sodium salts. The spectra of the former reveal their structural features, while with the latter information on the molecular weight can be obtained. The limit of detection (about 1 microgram) allows the analysis of prostaglandin solutions of 1 microgram/microliter concentrations used in pharmacological tests.

[Chromatographic-mass spectrometric analysis of sialic acids of disialosyllactosylceramides from the calf thymus]. / Khromatomass-spektrometricheskii analiz sialovykh kislot disialozillaktoziltseramidov timusa telenka.

Gas-liquid chromatography/mass spectrometry of the compounds obtained on methanolysis and deuterioacetylation of the permethylated gangliosides has demonstrated that disialosyllactosyl ceramides of calf thymus contain three components - NeuAc alpha 2----8NeuAc alpha 2----LacCer, NeuAc alpha 2----8NeuGc alpha 2----LacCer and NeuGc alpha 2----8NeuGc alpha 2----LacCer.

[Gangliosides of murine B-lymphoma MORC-406]. / Gangliozidy B-limfomy MORC-406 myshei.

Gangliosides of murine B-lymphoma MOPC-406 were studied, using biochemical methods and specific antibodies. The lymphoma was found to contain 12 ganglioside components which were identified as N-acetyl and N-glycoloyl forms of SiaLacCer, SiaGgOse3Cer, II3SiaGgOse4Cer, IV3SiaGgOse4Cer and II3IV3Sia2GgOse4Cer.

[Gangliosides from human placenta]. / Gangliozidy platsenty cheloveka.

Gangliosides of human placenta were studied, using biochemical methods and specific antibodies. The placenta was found to contain three types of gangliosides with oligosaccharide chains Lac, GgOse4 and nLcOse4.

Antiproliferative activity of ceramides isolated from normal human ovary and ovarian tumor.

Ceramides modulate cell growth, differentiation and apoptosis. We have previously demonstrated that human epithelial ovarian tumors contain dihydroceramides that are absent from normal ovary. Dihydroceramides differ in their biological effects from ceramides; therefore antiproliferative activity of ceramides isolated from normal human ovary and ovarian tumors was studied. Ceramides (3 microM) of normal ovary are more potent inhibitors of [3H]thymidine incorporation into human ovarian carcinoma cells (CaOv) than ceramides of ovarian tumors. Effects of various pools of tumor ceramides were similar regardless of significant differences in the contents of sphingenine and sphinganine. It is suggested that antiproliferative activity of ceramides depends not only on the sphingoid base structure but also on the fatty acid structure.

[Structure of lymphoma gangliosides in EL-4 mice]. / Struktura gangliozidov limfomy EL-4 myshei.

The structure of the major gangliosides from murine lymphoma EL-4 was established by acid hydrolysis, methanolysis, methylation analysis, neuraminidase treatment and chromium trioxide oxidation. Two of these gangliosides were identified as the N-acetyl and N-glycoloyl forms of the GM2 ganglioside. The third ganglioside making up to 40% of the total ganglioside pool contained two sialic acid residues and was identified as a GD2 ganglioside which up to now had not been reported in extraneural tissues.

The gangliosides of adult human aorta: intima, media and plaque.

The composition, structure and localization of gangliosides of aorta taken from subjects who had died after myocardial infarction were studied. Individual gangliosides were purified by high-performance liquid chromatography and high-performance thin-layer chromatography and were characterized on the basis of their chromatographic mobility, carbohydrate composition, neuraminidase hydrolysis and methylation analysis. The main aortic gangliosides were identified as GM3, GM1, GD3, GD1a and GT1b. Significant differences in the ganglioside composition of intima and media were detected and the ganglioside profile of atherosclerotic plaques was found to differ markedly from that of unaffected intima. The latter was characterized by high content of GD3, a ganglioside thought to be associated with membrane permeability, cell interaction, adhesiveness and growth and to suppress unspecific immune responses. Possible implications of the results in low-density lipoprotein binding to the arterial wall and in immunological changes induced by atherosclerotic lesions are discussed.

Content and structure of ceramide and sphingomyelin and sphingomyelinase activity in mouse hepatoma-22.

The relative content of phosphatidylcholine is lower and that of sphingomyelin is higher in transplantable fast growing mouse hepatoma-22, thus decreasing their ratio approximately 2.5-fold versus normal liver. The ceramide content and the neutral sphingomyelinase activity is markedly higher (3- and 6.5-fold, respectively), whereas the acid sphingomyelinase activity is 4-fold lower in hepatoma-22 versus normal liver. The content of saturated fatty acids in ceramide and sphingomyelin of hepatoma-22 is higher than in normal liver. All sphingolipids of hepatoma-22 contain a considerable amount (25-37%) of sphinganine (dihydrosphingosine) along with sphingenine (sphingosine), whereas sphingolipids of normal liver contain predominantly sphingenine (over 95%). These results indicate that the activity of enzymes involved in sphingolipid biosynthesis and catabolism is disturbed in the transplantable mouse hepatoma-22 compared to normal liver.

Interaction of influenza virus with gangliosides and liposomes containing gangliosides.

It has already been shown that influenza virus binds unspecifically to liposomes containing ganglioside GM1 wheras with gangliosides GD1b and GT1b binding occurs in a specific and saturable manner [Slepushkin et al. (1986) Biol. Membr. 3, 229-235]. In the present study the mode of interaction between influenza virus and various gangliosides or phospholipid liposomes containing cholesterol and gangliosides has been investigated. The influence of exogenous gangliosides on the structure of the viral envelope was studied using fluorescent and photoactivatable phospholipids incorporated into the viral membrane. With both types of probes maximal effects of gangliosides were caused by GT1b. Addition of that ganglioside resulted in a marked decrease in the fluorescence polarization (P) of fluorescent labeled virus as well as in substantial changes in the binding of photoactivatable analogues of sphingomyelin and phosphatidylcholine to virus proteins, mainly hemagglutinin. The effects of GT1b and GD1b on P value were comparable, whereas gangliosides with other oligosaccharide chains caused much smaller changes in P. Furthermore GT1b but not GM1 influenced phospholipid-hemagglutinin cross-linking. Interaction of the virus with large unilamellar liposomes was monitored by two fluorescence assays based on resonance-energy transfer from the tryptophans and tyrosines of viral proteins to vesicles labeled with a triacylglycerol (anthrylvinyldioleoylglycerol) or from these labeled vesicles to virions labeled with a perylenoyl derivative of galactosylcerebroside (PGalSph). A third fluorescence assay was based on relief of self-quenching in PGalSph-labeled virions, upon low-pH-induced virus-liposome fusion. With all three fusion assays the changes of fluorescence caused by GT1b were more pronounced than those induced by GM1. On the other hand, virus-induced release of [14C]glucose from multilamellar liposomes was enhanced by GM1 but not by GT1b or GD1b. It is concluded that the interaction of GT1b or GD1b with virus hemagglutinin induces a rearrangement of the viral lipids rendering lipid bilayer areas of the viral envelope significantly fluid, which in turn promotes fusion of the virus with target membranes. Probably virus-liposome fusion and virus-induced liposome leakage are brought about by different mechanisms depending on specific or unspecific binding of the virions to the target.