Search PubMed⌕ Search

Biomedical subjects

B E Samuelsson

Publications and source records attributed to B E Samuelsson.

At least 91 records · Page 5Linked to original sources
PubMed1979

The lipid composition of the electric organ of the ray, Torpedo marmorata, with specific reference to sulfatides and Na+-K+-ATPase.

The lipids from the electric organ of the ray, Torpedo marmorata, have been isolated and characterized. The major lipids were cholesterol, choline phospholipids, ethanolamine phospholipids, and sphingomyelins. The major fatty acids of ethanolamine phospholipids were 18:1, 18:0, 22:6, and 20:4. More than 50% of the acids in choline phospholipids were 16:0. The sphingomyelins consisted of five major ceramide species, all with sphingosine and the fatty acids 14:0, 15:0, 16:0, 22:1, and 24:1. The fatty acid 15:0 was mostly branched (n-2), a fatty acid earlier identified in sphingomyelins of the rectal gland of spiny dogfish. All long-chain bases were dihydroxy bases with a small percentage of branched chains. Sulfatides (cerebroside sulfate) made up the largest glycolipid fraction. The polar moiety wase galactose-3-sulfate. The fatty acids were normal and 2-hydroxy; the homologue 24:1 was the most abundant in both types of fatty acids. Most fatty acids were higher homologues of mono-unsaturated acids, but normal 18:0 fatty acid was also found. The long-chain bases were both dihydroxy and trihydroxy, with very small amounts of branched chains. The two major ceramide species of sulfatides were sphingosine combined with normal and hydroxy 24:1 fatty acids, respectively. Smaller amounts of trihydroxy base (18:0) were found linked to hydroxy 24:1 fatty acid, but not to its normal homologue. The cerebrosides contained the two major species mentioned above but lacked the trihydroxy base-hydroxy fatty acid species. The ratio of the activity of Na+-K+-dependent ATPase (EC 3.6.1.3) and the concentration of sulfatides was similar to ratios found for other tissues with normal and increased Na+ and K+ transporting capacity. The significance of this finding is discussed.

Animals↗
PubMed1978

The identification of sulphatides in human erythrocyte membrane and their relation to sodium-potassium dependent adenosine triphosphatase.

Sulphatides (ceramide galactose-3-sulphate) were isolated from human erythrocyte membranes. The amount obtained was 3.3 mg from 6.7 kg of wet cells, or 1.5 X 10(-9) mol per g dry cells. The polar part was shown to be galactose-3-sulphate by chromatographic analysis, infrared spectrometry, and mass spectrometry after solvolytic desulphation. The ceramide part consisted of three major molecular species, sphingosine-palmitic acid, sphingosine-2-hydroxypalmitic acid, and phytosphingosine-2-hydroxypalmitic acid, as shown by thin-layer chromatography, mass spectrometry of galactosylceramides after desulphation, and gas chromatography of components after hydrolysis. The composition differed from other human erythrocyte sphingolipids. Although the amount of sulphatides is very low for erythrocyte, the ratio of sulphatide concentration and Na+-K+-ATPase activity [EC 3.6.1.3] is similar to the situation found for several animal tissues with an increased level of Na+ transport. This finding is discussed in relation to a recent model of sulphatide function in a transport unit for Na+ and K+ (cofactor site model).

Adenosine Triphosphatases↗
PubMed1977

Structural analysis by mass spectrometry of the major mammalian retinal ganglioside, a sialyl-sialyl-dihexosyl-ceramide.

The major mammalian retinal ganglioside was analysed by mass spectrometry. Three types of derivatives were used, the fully methylated, the methylated and reduced and the methylated, reduced and trimethylsilylated compound. The mass spectra unambiguously showed the ganglioside to be a sialyl-sialyl-dihexosyl-ceramide. This is the first conclusive proof that the two N-acetylneuraminic acids are bound to each other constituting the terminal disaccharide. The major species contained sphingosine and stearic acid.

Animals↗
PubMed1976

Studies of the ligand binding to cholera toxin, I. The lipophilic moiety of sialoglycolipids.

The fixation of cholera toxin by ganglioside GGtet1 is dependent on the nature of the carbohydrate as well as the lipid moiety of the glycolipid. The role of the lipid in binding to the toxin investigated with synthetic ganglioside analogues (gangliosidoides). The interaction between glycolipid and toxin was followed by precipitate formation, by inhibition of toxicity and in polyacrylamide gel electrophoresis. For specific precipitation, an aliphatic hydrocarbon chain at least 14 C-atoms in length is required. Some of the gangliosidoides form high molecular weight complexes with cholera toxin at lower molar ratios of ligand to protein than the natural compound. None of the synthetic gangliosidoides equalled natural ganglioside in its ability to inhibit the effects of the toxin in vivo, but some did show considerable inhibitory activity ih monosialo-gangliotetraose or corresponding sialo-glycolipids prevents the easy degradation of the B-protein of cholera toxin into protein subunits by sodium dodecylsulfate.

Bacterial Toxins↗
PubMed1975

Characterization of dog small intestinal fucolipids with human blood group H activity.

Fucolipids with human blood group H activity were isolated from several dog small intestines. On the basis of mass spectrometry, periodate oxidation, enzyme degradation, methylation, and immunologic studies the following structure is proposed: Fucalpha(1 yields2)Galbeta(1 yields 4)Glc-NAcbeta(1 yields 3)Galbeta(1 yields 4)Glc-ceramide. The ceramide was shown by mass spectrometry to contain hydroxyhexadecanoic acid and phytosphingosine as major consitutuents.

ABO Blood-Group System↗
PubMed1975

Main structures of the Forssman glycolipid hapten and a Leb-like glycolipid of dog small intestine, as revealed by mass spectrometry. Difference in ceramide structure related to tissue localization.

Two glycolipids of dog small intestine, one with Forssman activity and one with Leb-like activity, have been characterized by mass spectrometry of methylated, and methylated and reduced (LiAlH4) derivatives. The Forssman glycolipid was conclusively shown to be a pentaglycosylceramide with the carbohydrate sequence hexosamine-hexosamine-hexose-hexose-hexose-ceramide, and with sphingosine (dihydroxy base) as major long-chain base and normal fatty acids as the only fatty acids. The Leb-like glycolipid was a hexaglycosyl-ceramide with sequence fucose-hexose-[fucose-] hexosamine-hexose-hexose-ceramide and with phytosphingosine (trihydroxy base) as major long-chain base and only 2-hydroxy fatty acids as fatty acids. The difference of two hydroxy groups in the ceramide between the two glycolipids may be related to a different tissue localization. As shown by immunofluorescense study the Forssman activity was associated with the lamina propria and the Leb-like activity to the glandular epithelium of dog small intestine.

Aluminum↗
PubMed1975

Characterization by mass spectrometry of blood group A active glycolipids from human and dog small intestins.

Glycolipids with blood group A activity isolated from human and dog small intestine have been characterized by mass spectrometry of intact lipid in methylated and in methylated and reduced (LiAiH4) form. Without degradative studies the glycolipids were conclusively shown to be hexaglycosyleramides with phytosphingosine as the major long-chain base and hydroxypalmitic acid as the major fatty acid. The exact sugar ratio was hexose-hexosamine-deoxyhexose 3:2:1 and the sequence established as hexosamine-[deoxyhexose-]hexose-hexosamine-hexose-hexose-ceramide. Evidence is presented that mass spectrometry can differential between type ) and type 2 saccharide chains.

ABO Blood-Group System↗