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Biomedical subjects

B E Samuelsson

Publications and source records attributed to B E Samuelsson.

At least 73 records · Page 4Linked to original sources
PubMed1983

New gangliosides from human erythrocytes.

We have identified a number of gangliosides from human erythrocytes that have not previously been detected in these cells, including two new compounds. The gangliosides were separated into monosialo- and disialoganglioside fractions by DEAE-column chromatography. Two monosialogangliosides that have not been previously detected in these cells are GM2 and GM1. Two other monosialogangliosides have the same carbohydrate structure, NeuAc(alpha 2-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4) Glc-Cer, but they contain different fatty acids. The compound with higher chromatographic mobility (MG-5) contains a predominance of C22 and C24 fatty acids, whereas the principal fatty acid of the slower compound (MG-6) is C16. Both gangliosides are receptors for human anti-p and anti-Gd cold agglutinins. Six disialogangliosides not identifed previously in human red cells include GD3, GD1a, GD1b, DG-3, (formula: see text). The latter two are newly identified compounds and DG-4 contains a sugar sequence that has not been described previously, sialic acid residues linked to different hydroxyl groups of the same galactose.

Carbohydrate Conformation↗
PubMed1982

Lewis blood group fucolipids and their isomers from human and canine intestine.

Glycolipids containing fucose linked to N-acetylglucosamine were isolated and characterized from 14 individual human and 13 individual dog intestines. From 8 of the dog intestines, Lewis a isomer fucolipids were isolated, all identical and having the structure Gal(beta 1 leads to 4)[Fuc alpha 1 leads to 3]GlcNAc(beta 1 leads to 3)Gal(beta 1 leads to 4)Glc-ceramide. Lewis b isomer fucolipids were isolated from 12 of the intestines, all identical and having the structure Fuc(alpha 1 leads to 2)Gal(beta 1 leads to 4)[Fuc alpha 1 leads to 3]GlcNAc(beta 1 leads to 3)Gal(beta 1 leads to 4)Glc-ceramide. Lewis a-active glycolipids were isolated as the sole major fucolipid in 6 of the human intestines and differed from the canine isomer only in the position of the linkage of galactose to N-acetylglucosamine, having the beta 1 leads to 3 (type 1) rather than the beta 1 leads to 4 (type 2) linkage. Lewis b-active fucolipids were isolated from 8 human intestines and differed from their canine isomer only in that they, too, had the type 1 rather than the type 2 oligosaccharide chain. Lewis a and b glycolipid isomers commonly co-existed in canine intestine as major fucolipids whereas Lewis a and b glycolipids did not so co-exist in human intestine. In all of the fucolipids, only hydroxylated fatty acids were present and phytosphingosine and sphingosine were the predominant long chain bases. These findings are of interest in the biosynthesis of these substances and in their genetic expression.

Animals↗
PubMed1982

Chemical and clinical studies on the interaction of Escherichia coli with host glycolipid receptors in urinary tract infection.

The role of glycosphingolipids as host receptors, and fimbriae as bacterial ligands, for the adhesive and hemagglutinating reactions of uropathogenic E. coli was assessed. Glycolipids including globotetraosylceramide and globotriaosylceramide, which contain the disaccharide Gal alpha 1 leads to 4Gal were bound by many strains isolated from patients with pyelonephritis and cystitis. The fimbriae of one strain were shown to serve as ligands for these receptors. Although most pyelonephritic E. coli recognized globotetraosylceramide, as measured by the agglutination of glycolipid coated erythrocytes, some also recognized D-mannose residues (i.e. mannose-sensitive hemagglutination). Several strains were exclusively mannose-sensitive or bound neither globotetraosylceramide nor mannose. A genetic basis for susceptibility to infection was indicated. The erythrocytes of blood group P2 have lower amounts of Gal alpha 1 leads to 4Gal containing glycolipids than individuals of blood group P1. Blood group P2 was significantly less frequent (1/28) among patients with recurrent urinary tract infection compared to the normal population (10/40, p less than 0.02). Therefore, globoseries glycolipids may be determinants of susceptibility to urinary tract infection.

Binding Sites↗
PubMed1980

Mass spectra and NMR spectra of gangliosides containing fucose.

Two gangliosides containing fucose, prepared from minipig posterior root ganglion, were analyzed as methylated, methylated-reduced and methylated-reduced-trimethylsilylated derivatives by mass spectrometry and NMR spectroscopy and shown to have the following structures:Fuc alpha 1 leads to Hex beta 1 leads to 3HexNac (comes from NeuAc) beta 1 leads to Hex beta 1 leads to Hex beta 1 leads to 1Ceramide Fuc-Hex-HexNAc (NeuGc)-Hex-Hex-Ceramide.

Animals↗
PubMed1980

Structural analysis by mass spectrometry and NMR spectroscopy of the glycolipid sulfate from Halobacterium salinarium and a note on its possible function.

The major glycolipid sulfate of the extreme halophile Halobacterium salinarium was isolated and characterised mainly by mass spectrometry and NMR spectroscopy. The mass spectrum of the permethylated, desulfated and trimethylsilylated derivative showed the molecule to be a trihexosyl glycerol C20-diether with the sulfate group on the terminal hexose. A 3-position of the sulfate was indicated by the mass spectrum obtained after acetylation and trimethylsilylation (solvolysis of sulfate and replacement by a trimethylsilyl group). The NMR spectrum of the desulfated permethylated glycolipid gave conclusive evidence for the presence of one beta and two alpha anomeric protons. With the knowledge of degradation data it was possible to assign the beta signal to galactose (terminal hexose), and the alpha signals to glucose and mannose. These data together make it likely that the glycolipid sulfate is identical in structure with the glycolipid from Halobacterium cutirubrum characterised previously (M. Kates and P.W. Deroo, J. Lipid Res., 14 (1973) 438). On the basis of a suggested function of cerebroside sulfate of animal origin (identical polar end with the bacterial glycolipid: beta-galactopyranose-3-sulfate) and the present knowledge of ion transport in Halobacteria, it is proposed that the bacterial glycolipid may function as a selective K+ receptor for the K+ transport from a high-Na+ and low-K+ outside medium.

Glycolipids↗
PubMed1980

Blood group type glycosphingolipids of human cord blood erythrocytes.

The non-acid glycosphingolipids of cord blood erythrocytes, pooled from blood groups O and A respectively, were characterized by mass spectrometry in combination with immunologic and thin-layer chromatographic analyses. The glycosphingolipid pattern was compared to that of adult erythrocytes. Just as for adult blood, the major glycosphingolipid species were lactosylceramide and globotetraosylceramide (globoside). The triglycosylceramide fraction was quantitatively smaller in cord red blood cells and was also enriched in a triglycosylceramide with a terminal hexosamine, as conclusively shown by mass spectrometry. The amount of blood group A and H active glycosphingolipids appeared to be less in cord blood cells compared to adult cells was glycolipids with longer, probably branched chain structures were not detected. In contrast, increased amounts of penta- and hexaglycosylceramides lacking fucose and possibly being biosynthetic precursor substances to the ordinary blood group A and H glycosphingolipids were found typical for cord blood cells.

ABO Blood-Group System↗
PubMed1979

Characterization of cerebroside (monoglycosylceramide) from the sea anemone, Metridium senile. Identification of the major long-chain base as an unusual dienic base with a methyl branch at a double bond.

1. Cerebroside of the sea anemone, Metridium senile, has been isolated (0.6 mg/g dry tissue weight) and structurally characterized. 2. The structure was shown by mass spectrometry, NMR spectroscopy and degradative studies as beta-glucopyranosylceramide. The major fatty acids were 16 : 0 and 20 : 0 D-2-hydroxy fatty acids. The major base was a novel base, D-erythro-1,3-dihydroxy-2-amino-9-methyl-trans-4, trans-8-octadecadiene. 3. Some unusual fatty acids of marine origin are suggested to originate in this long-chain base by metabolic conversion. 4. The implication of the methyl branch position of the base on our current view of sphingolipid function in the plasma membrane is discussed.

Animals↗
PubMed1979

Selected ion monitoring of glycospingolipid mixtures. Identification of several blood group type glycolipids in the small intestine of an individual rabbit.

A novel application of selected ion monitoring was used for a mixture of non-acid glycosphingolipids of one rabbit small intestine. Earlier studies of permethylated and permethylated-reduced (LiAIH4) derivatives of model compounds have revealed a specificity and abundance of saccharide ions (terminal monosaccharide(s), disaccharide, trisaccharide, etc., and all sugars plus fatty acid) and of ceramide fragments that permit a conclusive detection of separate glycolipid species in a mixture. The sample (50-200 micrograms) was evaporated slowly (1-5 degrees C min-1 from 150-350 degrees C) from the direct inlet probe of an MS 902 mass spectrometer (electron ionization). Mass spectra with fragments up to about m/z 200 were collected on-line by a computer system. A successive partial separation was obtained for glycolipids with from one up to seven sugars. The structures of eight different compounds were identified. They all had 16:0, 22:0 and 24:0 2-hydroxy fatty acids and 18:0 trihydroxy base (phytosphingosine) as major ceramide components. The dominating complex glycolipid was a hexaglycosylceramide with a blood group B type of sequence. A blood group A type sequence was found in a second hexaglycosylceramide. In support of this, the native mixture showed blood group A and B activity. An intense peak, m/z 182, collected from methylated derivatives were evidence for a dominating type 2 carbohydrate chain of the core tetrasaccharide.

Animals↗