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At least 19 recordsLinked to original sources
PubMed1978

Structural studies on glycolipid of shellfish. II. Occurrence of 3-O-methylgalactosamine in oyster glycolipid.

3-O-Methyl hexosamine was found for the first time and characterized as one of the sugar components of oyster glycolipid. The alditol acetate of this sugar was identified as 3-O-methyl-N-acetylgalactosaminitol acetate by comparing its retention time on gas chromatography and mass spectrum with those of the authentic sample synthesized in this laboratory. The new sugar, 3-O-methylgalactosamine, occupied the non-reducing terminal position of the carbohydrate moiety of the lipid and was linked to the penultimate hexose by a (1 leads to 3) bond.

Animals↗
PubMed1979

Threshold effects on the lectin-mediated aggregation of synthetic glycolipid-containing liposomes.

Cholesterol analogs containing sugar residues linked by spacer groups to the cholesterol O can be incorporated into egg yolk lecithin small unilamellar liposomes. The synthetic glycolipid analogs distribute evenly on both sides of the bilayer. These liposomes are aggregated by the appropriate lectin. For example, when the sugar residue is a beta-galactoside the liposomes are aggregated by ricin and when it is an alpha-mannoside they are aggregated by Con A. The lectin-mediated aggregation of these liposomes is reversed by the addition of the appropriate sugar. The rates but not the extents of aggregation of these liposomes are highly sensitive to the amount of glycolipid incorporated. Below approximately 5% glycolipid incorporation the rate of the lectin-mediated aggregation of these liposomes is exceedingly slow, whereas above this level rapid aggregation proceeds. At all concentrations studied the synthetic glycolipids are incorporated in a unimodal fashion so that the observed threshold effects cannot be based on possible differences in the manner in which the glycolipids are incorporated at different concentrations. This conclusion is based on 1) studies with galactose oxidase that show that the percentage of galactose oxidation in a liposome prepared from a galactosyl-containing glycolipid is independent of glycolipid concentration, and 2) studies on the aggregation of liposomes containing mixed glycolipids in which the glycolipids are shown to behave independently. The importance of a critical density of membrane-bound receptors in order for aggregation to occur is discussed.

Chemical Phenomena↗
PubMed1978

The composition and biosynthesis of the glycoproteins and glycolipids of the rabbit small-intestinal brush border.

1. The glycoprotein and glycolipid composition of isolated rabbit small-intestinal brush borders has been studied. 2. The total glycoprotein fraction contains an average 95 microgram carbohydrate per mg protein, composed of mannose, galactose, fucose, N-acetylglucosamine and N-acetylgalactosamine. Glucose is also present but sialic acid is absent. 3. The isolated glycolipids include ceramide lactoside, ceramide trihexoside and two N-acetylglucosamine-containing glycolipids. Sialic acid containing glycolipid (gangliosides) is present only in trace quantities. 4. The biosynthesis of the brush border-bound glycoproteins and glycolipids has been studied following intraperitoneal injection with D-[1-14C]glucosamine and isolation of the brush borders at intervals between 3 and 24 h. 5. The total glycoprotein fraction labels maximally 7.5 h after injection and subsequently exhibits an exponential loss of radioactivity with a half-life of 11.2 h. The labelling kinetics of one of the glucosamine-containing glycolipids is similar to that of the glycoproteins in that it labels maximally between 7.5 and 12 h, but the second glucosamine-containing glycolipid labels later at approximately 18 h. These results indicate that the glycoproteins and glycolipids are actively synthesized and degraded within the mature small intestinal enterocyte and that individual glycolipids turn over independently.

Animals↗
PubMed1979

Production of monoclonal antibodies specific for two distinct steric portions of the glycolipid ganglio-N-triosylceramide (asialo GM2).

Two hybrid cell lines were prepared by the fusion of mouse myeloma cells with the spleen cells of BALB/c mice that had been immunized with the glycolipid ganglio-N-triosylceramide (asialo GM2). The specificity of the monoclonal antibodies produced by these hybridomas, one an IgM and the other an IgG3, has been defined by hemagglutination inhibition, complement fixation, and lysis of glycolipid liposomes by antibody and complement. A major determinant recognized by the IgM antibody is the nonreducing terminal N-acetylgalactosamine including the C6 primary hydroxyl group, but excluding the C2-acetamide group of N-acetylgalactosamine, because oxidation with galactose oxidase produced a structure showing only minimal cross-reaction with the IgM but replacement of the N-acetyl group with an N-n-butyryl group produced a glycolipid that reacts with IgM antibody to the same extent as with the unmodified glycoplipd. A major determinant recognized by the IgG3 antibody is the terminal N-acetylgalactosamine including the C2-acetamido group, but excluding the C6 primary hydroxyl group of N-acetylgalactosamine, because replacement of the N-acetyl group with an N-n-butyryl group produced a glycolipid that did not react with the IgG3 antibody; in striking contrast the IgG3 antibody reacted with the C6-oxidized glycolipid as well as with the native glycolipid. Neither antibody reacted significantly with any other natural glycolipids tested including several that are structurally related to asialo GM2 such as ganglioside GM2, ganglio-N-tetraosylceramide (asialo GM1), or ceramide dihexoside. These results indicated that in addition to the fine structure specificity described above both antibodies recognize the nonreducing terminal GalNAc beta 1 leads to 4Gal structure. The strict antigenic specificity of these monoclonal anti-glycolipid antibodies indicates their great potential as specific probes for cell surface studies.

Animals↗
PubMed1979

Binding of Salmonella minnesota R-form glycolipid mR595 to rat fibroblasts and its effect on cell metabolism and cell behaviour.

Trypsinized normal rat embryo fibroblasts and untrypsinized and trypsinized transformed rat fibroblasts have two orders of binding sites for bacterial glycolipid mR595. The high order sites fix 1--3 micrograms glycolipid mR595/10(5) cells and those of the low order fix about 6 microgram glycolipids mR595/10(6) cells. Ca++ is required for the low order glycolipid mR595 binding to be trypsinized but not to the untrypsinized transformed rat fibroblasts. The low order binding is temperature dependent with the transition temperature lying between 25 and 37 degrees C. Exogenously added ganglioside and glycoproteins contained in the fetal calf serum do not inhibit fixation of glycolipid mR595. Only beta-lipoprotein at high concentrations is slightly inhibitory. Glycolipid mR595 fixation to transformed fibroblast does not alter their morphology and appears to slightly improve cell attachment to substratum. Glycolipid mR595 fixation results in a lengthening of the S-phase of the cell cycle and a reduction in 2-deoxyglucose uptake. Uptake of inorganic phosphate is not affected. Inhibition of phospholipid synthesis is observed in mR595 fixed fibroblasts whereas synthesis of cell surface glycoproteins and the content of cellular gangliosides is not affected.

Binding Sites↗
PubMed1979

Glycolipids and fatty acids of two dog kidney cell lines.

Glycolipid and fatty acid compositions were studied in whole cells and plasma membranes from two dog kidney cell lines (Madin-Darby and SV40-transformed cells) grown in monolayer and suspension cultures. Glycolipids, which account for 5% or less of the total lipids in dog kidney cells, were substantially increased in plasma membranes relative to whole cells. Sialoglycolipids more complex than a Tay-Sachs-like ganglioside were not found in any whole-cell or plasma-membrane preparation of this study. Dog kidney cells transformed by SV40 virus contained primarily a less complex sialoglycolipid, haematoside. Neutral glycolipids comprised 26-43% of the total glycolipid content in Madin-Darby preparations, whereas in transformed cells and membranes neutral glycolipids constituted only 1-22% of the total glycolipid content. Ceramide trihexoside was found in Madin-Darby cultures, but not in transformed cultures. The values for short-chain fatty acids from neutral glycolipids and for saturated fatty acids were generally higher than the values for these fatty acids in calf serum.

Animals↗
PubMed1978

Enzymatic synthesis of blood-group Lewis-specific glycolipids.

A blood-group Lewis precursor glycolipid was isolated from the plasma of a Lewis-negative individual [Le(a--b--)] and treated with fucosyltransferases from human gastric mucosa and GDP-fucose. Subsequently the glycolipid was adsorbed onto Le(a--b--) erythrocytes and the presence of blood-group Lewis antigens was assessed by passive hemagglutination with anti-Lewis sera. It was shown that the precursor glycolipid was enzymatically transformed to blood-group Lewis a (Lea) and Lewis b (Leb) specific glycolipids. Leb-glycolipid was also synthesized by fucosylation of an isolated Lea-glycolipid. Moreover Le(a--b--) erythrocytes were shown to develop Lea and Leb activities when subjected to enzymatic fucosylation, thus showing that Lewis-negative cells carry blood-group Lewis precursor glycolipid on the surface of their membrane. Le(a + b--) erthrocytes, upon enzymatic fucosylation, acquired Leb activity.

Epitopes↗
PubMed1978

Possible role of macrophage glycolipids as receptors for migration inhibitory factor (MIF).

Guinea pig peritoneal exudate cells incubated with water soluble glycolipids obtained from macrophages show an enhanced response to migration inhibitory factor. Incorporation of these glycolipids into liposomes greatly facilitates their interaction with indicator cells. Enhancement of peritoneal exudate cell responsiveness to migration inhibitory factor was specific for glycolipids from guinea pig macrophages. Glycolipids extracted from guinea pig brain and polymorphonuclear leukocytes as well as several bovine and porcine glycolipids had no effect. Specificity of enhancement was not due merely to a preferential association of macrophage glycolipids with indicator cells. The possible role of macrophage glycolipids as receptors for MIF is discussed.

Animals↗
PubMed1979

Radioimmunoassay of glycosphingolipids: application for the detection of forssman glycolipid in tissue extracts and cell membranes.

Development of a radioimmunoassay for detecting glycosphingolipids has been difficult, primarily because of transfer of radiolabeled glycolipid antigen to the unlabeled antigen pool. This difficulty has been overcome by the use of a radiolabeled glycolipid-polymer. Thus, an assay system has been developed for measuring picomolar quantities of Forssman hapten glycolipid. This assay is based on competition for rabbit anti-Forssman antibodies between Forssman glycolipid and a radiolabeled Forssman polyacrylic hydrazide polymer. Antigen-antibody complexes are removed quickly and efficiently by binding to formalin-fixed Staphylococcus aureus and subsequent centrifugation. One nanogram of Forssman glycolipid can be readily detected both in plasma membrane preparations and in purified glycolipid fractions. The isoantigenic expression of Forssman glycolipid in human gastrointestinal tissues has been reported previously (Hakomori et al., 1977). Using the radioimmunoassay, the Forssman status of several additional cases has been determined quantitatively.

Animals↗
PubMed1979

[Study on glycolipids in human lung carcinoma of histologically different types (author's transl)].

Human lung carcinoma tissues with histological types of adenocarcinoma, squamous cell and small cell undifferentiated carcinomas were investigated for glycolipids. Carcinoma tissues, as well as normal adult and embryonic lungs contained ceramide mono-, di- and trihexosides, globoside and hematoside as major glycolipids. In addition to them, sulfatide which was identified as ceramide 3-sulfate-galactoside, was isolated in much lesser amount. The content of sulfatide was markedly increased in adenocarcinoma than that in other carcinomas and normal lung. Adenocarcinoma was also characterized by significantly lower level of total glycolipids which was largely due to the diminished contents of ceramide mono- and dihexosides, and hematoside, as compared to those in other two carcinomas. Squamous cell carcinoma had a characteristic pattern with an increment of hematoside. In small cell undifferentiated carcinoma, glycolipid contents were similar with those in squamous cell carcinoma but the relative composition of major glycolipids was markedly differed from that in other types. All the types of carcinoma examined showed marked increase of ceramide mono- and dihexosides (except for ceramide dihexoside in adenocarcinoma) compared to those in normal adult lung. Overall feature of glycolipids in embryonic lung appeared to be an intermediate between carcinomas and normal adult lung.

Adenocarcinoma↗
PubMed1977

SV40 tumor rejection induced by vesicular stomatitis virus bearing SV40 tumor-specific transplantation antigen (SV40-TSTA). II. Association of SV40-TSTA activity with liposomes containing VSV glycolipids.

Highly purified vesicular stomatitis virus (VSV) was obtained from VSV-infected SV40-transformed and from "normal" hamster cell lines. A glycolipid extract was prepared from these VSV preparations according to the Folch partition procedure. These glycolipids were rendered immunogenic to the Syrian hamsters when incorporated within liposomal membranes composed of lecithin/sphingomyelin/cholesterol (1/1/2 by weight). When the glycolipids were extracted from VSV grown on cell lines (TSV5-cl2 and EHSVi-cl1) which contained the SV40 tumor-specific transplantation antigen (SV40-TSTA), it was possible either to induce a tumor rejection or at least to slow the growth of the tumor in Syrian hamsters challenged with TSV5-cl2 cells. No protection was obtained in animals treated with liposomes containing glycolipids extracted from purified VSV grown on SV40-TSTA-negative cells (EHB). The SV40-TSTA could be a glycolipid of the transformed cell membrane which is incorporated within the VSV envelope.

Animals↗
PubMed1979

Specific inhibition of macrophage migration inhibition factor by fucosylated glycolipid RM.

The effects of glycolipids on the interaction of the MIF (migration inhibition factor) with rat macrophages were examined using a migration inhibition assay system. MIF activity was specifically blocked by fucosylated Glycolipid RM [Gal alpha 1-3Gal(2-1 alpha Fuc) beta 1-3GalNAc beta 1-3Gal beta 1-4Glc beta 1-1ceramide, (1978) J. Biochem. 83, 85-90], but not by Cytolipin R, hematoside, or blood group B active glycolipid [Gal alpha 1-3Gal(2-1 alpha Fuc) beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1ceramide]. Inhibition of MIF activity was proportional to the concentration of Glycolipid RM. These findings suggest that Glycolipid RM acts as a receptor for MIF.

Animals↗
PubMed1976

Relationship of structure to function in bacterial endotoxins. IX. Differences in the lipid moiety of endotoxic glycolipids.

Chemical, immunochemical, chromatographic, and endotoxic properties of five chromatographically pure glycolipids were compared. The preparations were extracted by chloroform-methanol from three Escherichia coli, one Salmonella minnesota, and one S. typhimurium Re heptoseless mutant strains. The local Shwartzman skin assay, the nonspecific resistance-enhancing effect, and the Limulus assays could not distinguish among the five glycolipids, all five being active in all three assays. Significant differences could be seen when the tumor resistance-enhancing effect of the glycolipids in mice was compared with the nonspecific TA3-Ha murine mammary adenocarcinoma growing in ascites form. Even greater variation was observed in the capacity of the preparations to enhance the nonspecific resistance of mice to virulent S. typhi 0901 infections. The data show that the five glycolipids are quite dissimilar in their biological effects. Similarly, thin-layer chromatography and molecular ratio determinations showed that differences exist in the chemical structure of the glycolipids. Accordingly, we claim that not only the polysaccharide but the lipid moiety as well may vary in various gram-negative endotoxin preparations.

Animals↗
PubMed1977

Alterations of neutral glycolipids in cells infected with syncytium-producing mutants of herpes simplex virus type 1.

The isolation of syncytium-producing mutants of herpes simplex virus type 1 (KOS strain), which cause extensive cell fusion during otherwise normal infections, has been reported previously (S. Person, R. W. Knowles, G. S. Read, S. C. Warner, and V. C. Bond, J. Virol. 17:183-190, 1976). Seven of these mutants, plus two syncytial strains obtained elsewhere, were used to compare the incorporation of labeled galactose into neutral glycolipids of mock-infected, wild-type-infected, and syncytially infected human embryonic lung cells. Five predominant cellular glycolipid species were observed, denoted GL-1 through GL-5 in order of increasing oligosaccharide chain length; for example, GL-1 and GL-2 correspond to glycolipids that contain mono- and disaccharide units, respectively. Wild-type virus infection caused an increase in galactose incorporation into GL-1 and GL-2 relative to GL-3 through GL-5. For a single labeling interval from 4 to 10 h after adsorption, syncytial infections generally resulted in a relatively greater incorporation into more complex glycolipids than did wild-type infections. One mutant, syn 20, was compared with wild-type virus throughout infection by using a series of shorter labeling pulses and appeared to delay by at least 2 h the alterations observed during wild-type infections. These alterations are apparently due to defects in synthesis, since prelabeled cellular glycolipids were not differentially degraded during mock or virus infection.

Cell Fusion↗
PubMed1978

Comparative study on glycolipid composition between two cell types of rat ascites hepatoma cells.

A comparative study of the glycolipids was performed on two cell lines of rat ascites hepatomas, island-forming and free cell types, and several marked differences were found as follows: 1. Hexose content in glycolipids derived from AH 7974F (free cell type) was about 3.6-fold as much as that from AH 7974 (island-forming cell type) on the basis of dry cell weight. 2. The glycolipids in the cells of AH 7974 were tentatively identified as glucosylceramide, lactosylceramide, galactosylgalactosylglucosylceramide, globoside and hematoside (GM3) by both thin-layer and gas-liquid chromatography. 3. On the other hand, the glycolipids in AH 7974F cells were glucosylceramide, lactosylceramide and at least four unknown lipids. 4. Structure of one of these unknown lipids was shown to be asialo-GM2 by methylation and enzymatic degradation studies. Moreover, the presence of asialo-GM1 was suggested by immunoprecipitation test with anti-asialo-GM1 serum. 5. Glucosylceramide and lactosylceramide from AH 7974F cells were found to possess hydroxy fatty acids as major fatty acids components, which were rare in these glycolipids from AH 7974 cells.

Animals↗
PubMed1979

Immunochemical studies of lipids. V. Effect of modified hydrophobic moiety on immunogenicity and immunologic reactivity of Forssman glycolipid.

The role of hydrophobic moiety in determining the immunologic properties of glycolipid haptens was studied with the derivatives of Forssman glycolipid modified by ozonolytic cleavage of double bonds in hydrocarbon chains. The immunogenicity was not affected by this modification; comparable antibody responses were elicited in rabbits immunized with intact or modified Forssman glycolipid, regardless of its different hydrophobicity, in complete Freunds adjuvant. Modified hydrophobic portions did not affect the class and specificity of antibodies produced. On the other hand, immunologic reactivity was strongly influenced by hydrophobic moiety; the ability to form immune precipitates with antibodies decreased as the hydrophobicity of glycolipid decreased. The reactivity in complement fixation and hemolysis inhibition tests also showed parallel decreases, though the addition of auxiliary lipids greatly reduced these differences in reactivity. The results indicate the different influences of hydrophobic moiety of glycolipids on their immunogenicity and immunologic reactivity in vitro.

Animals↗