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.

Further characterization of the structure of GM1b ganglioside from rat ascites hepatoma

A ganglioside named GM1b (Hirabayashi, Y., Taki, T., and Matsumoto, M. (1979) FEBS Let. 100, 253-257) with a sugar composition identical with that of GM1, II3 alpha NeuAc-GgOse4Cer (Gal beta 1 leads to 3GalNAc beta 1 leads to 4Gal(3 leads from 2 alpha NeuAc) beta 1 leads to 4G1c beta 1 leads to 1'ceramide), isolated from rat ascites hepatoma was further characterized. In contrast to GM1, the sialic acid in this ganglioside was susceptible to clostridial sialidase in the absence of bile salts. Based on the sequential enzymic hydrolysis, permethylation analysis and direct probe mass spectrometric analysis, the structure of this ganglioside is determined to be: NeuAc alpha 2 leads to 3Gal beta 1 leads to 3GalNAc beta 1 leads to 4Gal beta 1 leads to 4Glc leads to ceramide. The structure of this ganglioside is identical with that biosynthesized in vitro (Stoffyn, A., Stoffyn, P., and Yip, M. C. M. (1975) Biochim. Biophys. Acta 409, 97-103).

Isolation of two endo-beta-N-acetylglucosaminidases from fig latex

Two endo-beta-N-acetylglucosaminidases (mannosyl-glycoprotein 1,4-N-acetamidodeoxy-beta-D-glycohydrolase, EC 3.2.1.96) (type F-I and type F-II) have been isolated from fig latex. At pH 7.0, type F-1 was retained by the DEAE-Sephadex A-50 column, whereas type F-II was not adsorbed by the column. The optimum pH of type F-I was found to be pH 5.9 and type F-II, pH 5.4. Type F-I enzyme hydrolyzes the tri-mannosyl derivatives di-N-acetylglucosaminylasparagine faster than the penta- or hexa-mannosyl compounds. Type F-II hydrolyzes the penta- and hexa-mannosyl derivatives, but not the tri-mannosyl compound.

Carbon-13 nuclear-magnetic-resonance spectroscopy of Forssman hapten

The 13C n.m.r. spectrum of Forssman hapten was obtained at 25.16 MHz in [3H] chloroform/[2H] methanol (1:1, v/v), using purified glycosphinogolipid from canine intestinal mucosa (glycolipid I). All amide, olefin, anomeric, intersaccharide glycosidic ether, amide linkage, methyl and many methylene resonances were resolved and assigned. Analysis of the anomeric region reveals the following pentaglycosylceramide structure as originally proposed [Siddiqui & Hakomori (1971) J. Biol. Chem. 246, 5766-5769]: GalNAc (alpha 1 leads to 3) GalNAc (beta 1 leads to 3) Gal (alpha 1 leads to 4) Gal (beta 1 leads to 1) ceramide. Analysis of the amide, olefin and methylene regions reveals no alpha-hydroxy fatty acyl group and less than or equal to 6 mol% unsaturated fatty acyl groups are present. Chemical-shift assignments are reported for the anomeric and glycosidic ether carbon atoms of intersaccharide-linked alpha-galactose and N-acetyl-alpha-galactosamine residues. Two rules are proposed for the assignment of the anomeric form of 1 leads to 3 and 1 leads to 4 linkages of galactose and N-acetylgalactosamine residues present in the glycone of glyco-conjugates. The present study emphasizes the importance of the anomeric "window" (80-120 p.p.m.) in studies of glycone structure.

Isolation and characterization of a novel monosialosylpentahexosyl ceramide from Tay-Sachs brain

A novel monosialoganglioside was isolated from Tay-Sachs brains. It represented about 0.1% of the total ganglioside mixture. Compositional analysis by gas-liquid chromatography indicated that it contained glucose, galactose, N-acetylgalactosamine, N-acetylneuraminic acid, and long chain base in the molar ratio of 1:2:2:1:1. The ganglioside was found to be resistant to neuraminidase (Clostridium perfringens), beta-hexosaminidase (jack bean), and beta-galactosidase. However, it could be degraded by a human liver beta-hexosaminidase preparation in the presence of an activator to produce a glycolipid chromatographically identical with authentic IV3NeuAc-GgOse4-ceramide. This glycolipid product was resistant to beta-galactosidase (jack bean), but could be readily degraded to GgOse4-ceramide by neuraminidase. Mild formic acid hydrolysis degraded the intact ganglioside to an asialo derivative chromatographically identical with the pentahexosyl ceramide (GalNAc-Gal-GalNAc-Gal-Glc-ceramide) derived from GD1a-GalNAc. The asialo derivative could then be degraded to GgOse4-ceramide and GgOse3-ceramide by sequential treatment with jack bean beta-hexosaminidase and beta-galactosidase. These data suggest that the novel ganglioside is a monosialosylpentahexosyl ceramide with the sialosyl group attached to the penultimate galactose moiety of the pentahexosyl ceramide backbone, and it has the following structure: GalNAc(beta 1-4)Gal(beta 1-3)GalNAc(beta 1-4)Gal(beta 1-4)Glc-ceramide (formula see text).

Isolation and characterization of an endo-beta-galactosidase from a new strain of Escherichia freundii

A new strain of Escherichia freundii was isolated from human feces. Compared with the previous strain (Kitamikado, M., and Ueno, R. (1970) Bull. Jpn. Soc. Sci. Fish. 36, 1175-1180), this strain releases comparable levels of endo-beta-galactosidase with lower levels of exoglycosidases in the culture medium containing 0.3% of keratan sulfate. Endo-beta-galactosidase was purified by an improved purification procedure involving Amicon H1P10 hollow fiber filtration, QAE-Sephadex A-50, and CM-Sephadex C-50 chromatographies. The purified enzyme is completely free from proteases and exoglycosidases. The general properties of this enzyme are: molecular weight, 28,000; optimal pH, 5.5 TO 5.8; PI, pH 8.0. This enzyme hydrolyzed keratan sulfates isolated from different sources to produce 6-O-sulfo-GlcNAc beta1 leads to 3Gal as the major product. In addition, the specificity of this enzyme toward various glycoconjugates was also studied.

Complement activation by iodinated contrast media

Activation of the complement system by iodinated contrast medium (ICM) infusion was studied in 25 children with congenital heart disease who received 76% Urographin during angiocardiographic studies. Total hemolytic activity (CH50), C1q, C3, C4 and C3 activator were determined before and 2, 5, 10, 15 and 20 minutes after Urographin infusion. Results showed that CH50 decreased in 16 patients (64%), C3 in 12 patients (48%), C3 activator in 12 patients (48%), C1q in 11 patients (44%) and C4 in 11 patients (44%). No side effect was encountered in all patients. It is therefore concluded that both the classic and alternative complement pathways could be activated by ICM and no causal relationship could be found between the presence of complement activation and the occurrence of adverse reactions to ICM infusion.

Evidence for the presence of two separate protein activators for the enzymic hydrolysis of GM1 and GM2 gangliosides

Two different protein activators were isolated simultaneously from human liver for the enzymic hydrolysis of GM1 (Gal beta 1 leads to 3GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-galactosidase and GM2 (GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-hexosaminidase A. The hydrolysis of GM1 is stimulated only by the GM1-specific activator which has very little effect on the hydrolysis of GM2. The same is also true for the hydrolysis of GM2. The antiserum raised against GM1 activator did not cross-react with GM2 activator and vice versa. These results suggest the presence of two different activators for the separate hydrolysis of GM1 and GM2. In connection with the enzymic hydrolysis of GM1 and GM2, we found that the hydrolysis of GM2 by human hepatic beta-N-acetylhexosaminidase A was severely inhibited by a buffer of high ionic strength, whereas no such inhibition was observed in the hydrolysis of GM1 by beta-galactosidase.

Isolation and characterization of a heptaglycosylceramide from bovine erythrocyte membranes

A heptaglycosylceramide was isolated from bovine erythrocyte membranes. The structure was characterized to be Gal(alpha 1-3)Gal(beta 1-4)GlcNAc(beta1-3)Gal(beta 1-4)Glc-NAc(beta 1-4)al(beta 1-4)GlcCer. A hexaglycosylceramide that has the same sequence except for the terminal alpha-galactosyl unit has also been isolated. We have previously found that gangliosides isolated from bovine erythrocyte membranes contain a keratan sulfate type repeating unit --[3Gal(beta 1-4)-GlcNAc beta]--n. This study shows that the keratan sulfate type repeating unit is also present in the neutral glycosphingolipids of bovine erythrocyte membranes.

Carbon 13 NMR spectroscopy of a cerebroside. Proof of the beta-pyranosyl structure of D-glucosylceramide

The first 13C nuclear magnetic resonance spectrum of a cerebroside is reported. All signals of D-glucosylceramide (I), the cerebroside from human Gaucher's diseased liver, have been assigned by comparison of their chemical shifts with those of model compounds. This data has been used to demonstrate for the first time directly: (a) that the glucosyl moiety must exist in the pyranoside ring form and have a beta anomeric linkage, and (b) that the fatty acyl composition of the aglycon is: alpha-hydroxy, 0%; saturated, 86 +/- 2%; unsaturated long chain, 14 +/- 2%; and unsaturated short chain, less than or equal to 2%. The use of 13C signal shifts in the delta 80 to 120 region (anomeric window) for the assignment of glycon anomeric and ring forms demonstrated herein should be applicable to other glycoconjugates.

Occurrence of glycosphingolipids in chicken egg yolk

Chicken egg yolk was found to contain a unique glycosphingolipid pattern not seen in other types of tissue or cell. These glycosphingolipids were isolated in pure form and their structures established by sequential enzymic hydrolysis and permethylation analysis. The major gangliosides in chicken egg yolk are N-acetylneuraminosylgalactosylceramide, N-acetylneuraminosyl-lactosylceramide and di-N-acetylneuraminosyl-lactosylceramide. The only neutral glycosphingolipid found in chicken egg yolk is galactosylceramide.

Increased glycosphingolipid excretion associated with proteinuria

The urine of patients with proteinuria of various etiologies was examined to determine if proteinuria alone was associated with significant glycosphingolipiduria. In all cases of proteinuria examined, the level of glycosphingolipids in the urine was found to be markedly elevated. There was no evidence of a glycosphingolipid storage disorder in any case. It was concluded that significant glycosphingolipiduria may occur in proteinuria as well as in the glycosphingolipid storage disorders.

Characterization of gangliosides from bovine erythrocyte membranes

Two glucosamine-containing gangliosides, sialosylhexaglycosylceramides, were isolated from bovine erythrocyte membranes. Both gangliosides were hydrolyzed by neuraminidase isolated from Clostridium perfringens to become neutral hexaglycosylceramides. Based on the results of sequential enzymatic hydrolysis and gas chromatography-mass spectrometric analyses of the methylated sugars, the structures of these two gangliosides were shown to be NeuAcalpha2 leads to 3Galbeta1 leads to 4GlcNAcbeta1 leads to 3Galbeta1 leads to 4GlcNAcbeta1 leads to 3Galbeta1 leads to 4Glc-ceramide and NeuGcalpha2 leads to 3Galbeta1 leads to 4GlcNAcbeta1 leads to 3Galbeta1 leads to 4GlcNAcbeta1 leads to 3Galbeta1 leads to 4Glc-ceramide, respectively. In addition, N-acetyl- and N-glycolylneuraminosyllacto-N-neotetraosylceramides, and N-acetyl- and N-glycolylneuraminosyllactosylceramides were also found in bovine erythrocytes. The predominant fatty acids in these two gangliosides were C 22:0 and C 24:0. C-18 sphingosine was the major base detected.