Occurrence of ceramide-glycanase in the earthworm, Lumbricus terrestris

We have detected the presence of ceramide-glycanase in the earthworm, Lumbricus terrestris. We have also devised a simple method for the preparation of this enzyme from the earthworm. This enzyme cleaved the linkage between the ceramide and the glycan chain in LacCer, GbOse3Cer, GbOse4Cer, GbOse5Cer, GM3, GM2, GM1 and GD1a. By using tritium-labeled GM2 as substrate, the optimum pH of this enzyme was found to be between pH 4 and 4.5. In the earthworm, the ceramide-glycanase was mainly found in the muscle. The intestine was found to contain a very low level of this enzyme. Because of their easy availability, earthworms should become a convenient source for the preparation of ceramide-glycanase.

Absence of endo-beta-N-acetylglucosaminidase activity in the kidneys of sheep, cattle and pig

The kidneys of man, sheep, cattle and pig were all found to contain 1-aspartamido-beta-acetylglucosamine amidohydrolase activity. However, among these, only human kidney was found to contain endo-beta-N-acetylglucosaminidase activity. The absence of this enzyme in the kidneys of sheep and cattle explains why the oligosaccharides accumulated in, and excreted by, sheep and cattle afflicted with disorders of glycoprotein catabolism (i.e. alpha-mannosidosis and beta-mannosidosis) contain two N-acetylglucosamine residues at the reducing terminus instead of one, as is the case for human patients afflicted with similar disorders.

Structure of a new hexasaccharide from the coaggregation polysaccharide of Streptococcus sanguis 34

The major constituent of a coaggregation polysaccharide from Streptococcus sanguis 34 is a hexasaccharide, isolated as the alditol. The proposed structure is alpha-D-GalpNAc-(1----3)-beta-L-Rhap-(1----4)-beta-D-Glcp-(1----6) -beta-D-Galf- (1----6)-beta-D-GalpNAc-(1----3)-D-Galol, based upon g.l.c.-m.s. of alditol acetates and partially methylated alditol acetates, f.a.b.-m.s., 1H-n.m.r. spectroscopy, g.l.c.-m.s. of trimethylsilylated (+)- and (-)-2-butyl glycosides, and cleavage by alpha-N-acetylgalactosaminidase. The structural deduction was facilitated by cleavage of the hexasaccharide at the furanoside linkage by 48% hydrogen fluoride, and reduction of the product, to yield alpha-D-GalpNAc-(1----3)-beta-L-Rhap-(1----4)-beta-D-Glcp-(1----6) -D-Galol.

Biochemical basis of type AB GM2 gangliosidosis in a Japanese spaniel

The biochemical basis of a case of GM2 gangliosidosis in a Japanese Spaniel was studied. This dog had a massive accumulation of GM2 ganglioside in the brain. The beta-hexosaminidase activity in this affected dog brain was approximately 12 times higher than that of normal brain. However, the activity toward p-nitrophenyl-6-sulfo-2-acetamido-2-deoxyglucopyranoside was only four times higher in the affected brain than in normal brain. The GM2 activator preparation obtained from the normal dog brain could stimulate the hydrolysis of GM2 ganglioside by beta-hexosaminidase isolated from the affected dog. However, the corresponding activator fraction from the affected dog could not stimulate such a reaction. It was concluded that the biochemical basis of the GM2 gangliosidosis in this Japanese Spaniel was due to the attenuation in the stimulatory activity of GM2 activator. This case represents the first animal form similar to the activator deficiency (or defect) of Type AB GM2 gangliosidosis in humans.

Accumulation of globotriaosylceramide in a case of leiomyosarcoma

Analysis of the glycosphingolipid composition in one case of uterine leiomyosarcoma metastasized to the liver showed an accumulation of globotriaosylceramide as compared with normal liver and uterus from which the tumour originated. The structure and the amount of glycosphingolipids were established by using specific glycosidases, permethylation analysis and h.p.l.c. The reason for the accumulation of globotriaosylceramide in leiomyosarcoma remains to be answered.

A unique glycosphingolipid-splitting enzyme (ceramide-glycanase from leech) cleaves the linkage between the oligosaccharide and the ceramide

A novel type of enzyme which hydrolyzes the linkage between the ceramide and the sugar chain in various glycosphingolipids has been found in the leech, Hirudo medicinalis. This enzyme releases the intact oligosaccharide from LacCer, GbOse3Cer, GbOse4Cer, GbOse5Cer, nLcOse4Cer, GM3, GM2, GM1, GD1a and GT1 with the concurrent release of ceramides. By using tritium-labeled GM1 as substrate we found the optimum pH of this enzyme to be between pH 4 and 5. Since the enzyme cleaves the linkage between the ceramide and the sugar chain in various glycosphingolipids with no apparent preference toward the sugar chain, we propose to call this enzyme ceramide-glycanase.

Epidemiological studies on hemorrhagic fever with renal syndrome in China

Hemorrhagic fever with renal syndrome (HFRS) has been reported from greater than 20 provinces in China. The number of reported cases has increased markedly in recent years and surpassed 80,000 human cases in 1983. All of the cases reported before 1981 were from rural areas and were attributed to Apodemus rats. In 1981, outbreaks of cases associated with house rats were first reported. Cases associated with Apodemus agrarius were more severe than those associated with the house rat Rattus norvegicus. The rate of inapparent infection in the rural population of areas endemic for Apodemus-associated disease was lower than that of Rattus-associated urban disease. After the onset of the disease, IgG antibody levels increase rapidly, peak after one week, and persist for as long as 25 years. Lung tissues from 16 species of rodent, from two species of sorex, and from cats and weasels in the epidemic areas have been found to carry antigen. A. agrarius, Apodemus peninsulae, and R. norvegicus serve as the main reservoirs of HFRS in rural areas, forest areas, and urban areas, respectively.

Ganglioside patterns in normal and lepromatous armadillo tissues

Gangliosides derived from tissues of normal and lepromatous armadillos were examined by thin-layer chromatography. The ganglioside patterns produced by the Mycobacterium leprae-infected tissues varied from that of the normal tissue. Although increased levels of several gangliosides were observed in the infected tissues, there was an apparent preferential increase in GM3 gangliosides as determined by column chromatography and enzymatic hydrolysis.

Urinary endo-beta-galactosidase capable of depolymerizing polylactosaminoglycans

Human urine was found to contain an endo-beta-galactosidase capable of depolymerizing sulfated and non-sulfated polylactosaminoglycans. Using 0.05 M sodium phosphate buffer, pH 7.0, this enzyme was not retained by DEAE-Sephadex A-50 or concanavalin A-Sepharose. The urinary endo-beta-galactosidase liberated a disaccharide with chromatographic mobility identical to 6-O-sulfo-GlcNAc beta 1----3Gal as one of the major products from keratan sulfates isolated from whale nasal cartilage, bovine cornea, and human costal cartilage. It also liberated GlcNAc beta 1----3 Gal as one of the major oligosaccharides from erythroglycan. The oligosaccharide profiles produced from various keratan sulfates and erythroglycan by the action of urinary endo-beta-galactosidase are quite similar to those produced by Escherichia freundii endo-beta-galactosidase (Nakagawa, H., Yamada, T., Chien, J.-L., Gardas, A., Kitamikado, M., Li, S.-C., and Li, Y.-T. (1980) J. Biol. Chem. 255, 5955-5959). The presence of urinary endo-beta-galactosidase indicates the existence of a new catabolic pathway for polylactosaminoglycans. This pathway involves the cleavage of internal beta-galactosyl linkages of the glycan chain.

[Intracytoplasmic desmosome in squamous cancer cells of the lung in man]

Ultrastructure of intracytoplasmic (cytoplasmic) desmosomes in the squamous cancer cells of the human lung was studied by electron microscopy. In 17 cases of non-keratosic squamous cell carcinoma of the lung, intracytoplasmic (cytoplasmic) desmosomes were found in 4. In contrast to what previous investigators had proposed that the intracytoplasmic desmosomes are formed by cell fusion with the membrane being deep in the cell and cell digestion under the diffusion of hydrolytic enzymes, our result indicates that the intracytoplasmic desmosomes might be a structure formed by cell intima system itself during cell division. The structure suggests that the desmosomes originate from the cell intima system.

Presence of glycoproteins containing the polylactosamine structure in brain and liver of GM1 gangliosidosis patients. Comparative study between clinical types I and II, using endo-beta-galactosidase enzyme

The material derived from defective degradation of glycoproteins, which accumulates in brain and liver of a patient with GM1 gangliosidosis type I, was investigated, and the structure of the main storage compounds determined. For comparison, brain and liver of a patient with GM1 gangliosidosis type II were also analyzed. Analysis of the glycopeptides obtained after pronase digestion of the defatted residue indicates the storage of glycoprotein-like material in type I, but not in type II. Treatment with endo-beta-galactosidase showed that the stored material contained N-acetyllactosamine repeating units. Two major oligosaccharides, OS I and OS II, were isolated after the enzyme treatment, whose structures are: GlcNAc beta 1----3 Gal (OS I) and Gal beta l----4GlcNAc beta 1----3 Gal (OS II). Treatment with exo-beta-galactosidase transformed the trisaccharide OS II into the disaccharide OS I, indicating that the deficiency of beta-galactosidase in GM1 gangliosidosis type I, but not in type II, also affects glycoprotein catabolism, leading to the accumulation of glycopeptides containing terminal beta-galactosyl residues and N-acetyllactosamine repeating units. These results indicate the severe impairment in the catabolism of glycoconjugates with beta-linked galactose in type I, although this impairment is not as pronounced in type II.

[Preoperative radiotherapy and ultrastructural pathology of lung cancer]

The results of 26 patients with lung cancer treated by preoperative radiotherapy from March 1978 to October 1983 are reported. The pathological and ultrastructural findings as well as the reduction rate on the roentgenograph before and after radiation are observed in 8 patients. These 26 patients comprised 14 squamous cell carcinomas, 7 adenocarcinomas and 5 small cell carcinomas. The total tumor dose was 3,500-4,008 rad. The treatment results of 26 patients show that surgical resection rate was 92.3% and there were no operative mortality or death due to complications. The improvement in 1 year survival rate was 3.9% and 3 year survival rate was 17.5% as compared with resection alone in the same period. In pathology and ultrastructural studies, the preoperative radiation injuries directly the cancer cells in the tumor mass and also its surrounding tissues. Preoperative radiation is of benefit in the radical resection and the prevention of spread and metastasis of lung cancer.

Preparation and enzymatic degradation of monosulfogangliotriaosylceramide

Gangliotriaosylceramide 3'-sulfate (GgOse3Cer-II3-sulfate) contains the sugar sequence similar to that of GM2 ganglioside except that the NeuAc in GM2 is replaced by a sulfate group. Due to this structural similarity, we have studied the in vitro synthesis of GgOse3Cer-II3-sulfate using the system for GM2. Our results showed that GgOse3Cer-II3-sulfate could be synthesized from lactosylceramide 3'-sulfate and UDP-GalNAc catalyzed by N-acetylgalactosaminyltransferase prepared from rat brain (Dicesare, J. L., and Dain, J. A. (1971) Biochim. Biophys. Acta 231, 385-393). As in the case of GM2, the GgOse3Cer-II3-sulfate biosynthesized in vitro or isolated from rat kidney could also be cleaved by human beta-hexosaminidase A in the presence of GM2-activator (Li, S.-C., Hirabayashi, Y., and Li, Y.-T. (1981) J. Biol. Chem. 256, 6234-6240). The fact that the GM2-activator could stimulate beta-hexosaminidase A to hydrolyze both GM2 and Gg-Ose3Cer-II3-sulfate indicates that these two glycolipids may be catabolyzed by the same mechanism.

Activator protein required for the enzymatic hydrolysis of cerebroside sulfate. Deficiency in urine of patients affected with cerebroside sulfatase activator deficiency and identity with activators for the enzymatic hydrolysis of GM1 ganglioside and globotriaosylceramide

Urine specimens from two sibs affected with cerebroside sulfatase activator deficiency were examined to ascertain whether the deficiency of the supplementary activator protein required for the enzymatic hydrolysis of cerebroside sulfate was also evident in urine. Material from chromatographic fractionations was examined for the activator activity to avoid ambiguities resulting from protein inhibition. There were substantial deficits in all chromatographic fractions corresponding to activator-containing fractions of control urines. Since patient urines contained elevated amounts of lactosylceramide, digalactosylceramide, and globotriaosylceramide and since similarities between activators for cerebroside sulfate and GM1 ganglioside hydrolyses had been noted previously, the chromatographic fractions were also examined for activators in other glycosphingolipid hydrolase systems. There was coincidence of activators for the GM1 ganglioside/beta-galactosidase and the globotriaosylceramide/alpha-galactosidase A reactions with the cerebroside sulfatase activator in control urine fractions, and the patients' urines were deficient in activator activities for the three reactions. Identity of the three activators was suggested and antiserum to purified GM1 ganglioside activator was used to test this possibility. There were depressed levels of cross-reacting material in fractions of patient urines by Ouchterlony double diffusion and in unfractionated urine by enzyme-linked immunosorbent assay. Purified activators for the cerebroside sulfate and GM1 ganglioside systems showed lines of identity with no spurring on Ouchterlony double diffusion, identical mobility on immunoelectrophoresis, and similar stimulatory activities toward hydrolysis of the three glycosphingolipid species by their respective enzymes. Finally, the three activator activities were retained by anti-GM1-activator IgG coupled to Sepharose 4B. The results suggest strongly that the same protein entity serves as activator for the enzymatic hydrolysis of cerebroside sulfate, GM1 ganglioside, and globotriaosylceramide.

Characterization of human liver 3-O-beta-D-glucopyranuronosyl-cholesterol by mass spectrometry and nuclear magnetic resonance spectroscopy

We have isolated an unusual acidic glycolipid which was detected in the lower phase of the Folch partition of the total lipid extract of human liver during a routine isolation of glycosphingolipids. With the solvent systems commonly used for thin-layer chromatography of glycosphingolipids, this glycolipid has a mobility similar to GbOse3Cer, one of the major glycosphingolipids in human liver. Free cholesterol was released from this glycolipid upon treatment with beta-glucuronidase. The electron impact mass spectrum of the permethylated derivative of this glycolipid showed an intense peak at m/e 369 which is consistent with the cholesterol part of the molecule. It also showed m/e 233 and 201 which are derived from the permethylated glucopyranuronosyl residue. The final proof of the structure was accomplished by high resolution NMR spectroscopy which revealed the presence of beta-linked glucopyranuronosyl residue and cholesterol. Thus, the structure of this acidic glycolipid was conclusively established to be 3-O-beta-D-glucopyranuronosyl-cholesterol.

Isolation and characterization of a novel phytosphingosine-containing GM2 ganglioside from mullet roe (Mugil cephalus)

The major ganglioside from the roe of striped mullet (Mugil cephalus) has been isolated and purified. Compositional analysis of this ganglioside revealed that it contained an equimolar ratio of the following residues: N-acetylneuraminic acid, N-acetylgalactosamine, galactose, glucose, and the long-chain base. Further structural studies by sequential enzymatic hydrolysis, permethylation analysis, and proton NMR spectroscopy indicated that the structure of the oligosaccharide moiety was identical to that of GM2 ganglioside from human brain: GalNAc beta 1----4Gal beta 1----4(3----2 alpha NeuAc)-Glc----ceramide. This ganglioside, however, differed from brain GM2 in its ceramide portion. The most striking differences are the presence of large amounts of C18 and C20 phytosphingosine (over 80% of the total long-chain bases) and the preponderance of monounsaturated alpha-hydroxy fatty acids (over 80%). Such a phytosphingosine-containing GM2 ganglioside has never been reported.

Effect of modification of sialic acid on enzymic hydrolysis of gangliosides GM1 and GM2

In order to understand the mechanism of action of the activator proteins for the enzymic hydrolysis of GM1 (GM1-activator; Li, S.-C. and Li, Y.-T. (1976) J. Biol. Chem. 251, 1159-1163; for ganglioside designations, see Svennerholm, L. (1963) J. Neurochem. 10, 613) and GM2 (GM2-activator; Li, S.-C., Hirabayashi, Y., and Li, Y.-T. (1981) J. Biol. Chem. 256, 6234-6240), we have studied the effect of chemical modifications of GM1 and GM2 on their susceptibility to the activator-assisted enzymic hydrolysis. Chemically modified GM1 and GM2 were prepared by methyl esterification (Me-GM1 or Me-GM2) and reduction (HO-GM1 or HO-GM2) of the -COO- group of the sialic acid. Me-GM1 and HO-GM1 could be hydrolyzed by human hepatic beta-galactosidase in the presence of GM1-activator at rates comparable to that of the native GM1. However, in contrast to native GM2, Me-GM2 and HO-GM2 were resistant to the hydrolysis by human hepatic beta-hexosaminidase A in the presence of GM2-activator. When GM2-activator was replaced by sodium taurodeoxycholate, the native GM2 and both modified GM2 could be hydrolyzed by beta-hexosaminidase A. These results suggest that the carboxyl function of sialic acid in GM1 is not vital for beta-galactosidase or GM1-activator to carry out the cleavage of the terminal Gal. In the case of GM2 hydrolysis, the carboxyl function of sialic acid is involved in the interaction with GM2-activator. Our results also indicate that the mode of action of GM1-activator is different from that of GM2-activator and that the action of GM2-activator is different from that of sodium taurodeoxycholate.

Squamous cell carcinoma of the breast

Squamous cell carcinoma is a rare type of breast malignancy. Three patients are described. The clinical features, histologic findings, and postoperative course are described. All three patients had operation, and two received chemotherapy and radiotherapy. Two patients are well 2 and 6 years postoperatively, and the third patient died from extensive metastases within 34 months after radical mastectomy without postoperative chemotherapy and radiotherapy.

Comparative study of avian ovalbumins by means of glycosidase treatment and following HPLC analysis of their dansyl glycopeptides

Dansylated glycopeptides (DNS-GP) derived from ovalbumins (chicken, quail, goose and turkey) were treated with commercial endo-beta-N-acetyl-glucosaminidases (Endo-D and Endo-H). Susceptibility of DNS-GP components against those enzymes was examined by analysing the reaction product by HPLC. As reported previously (H. Iwase, Y. Kato and K. Hotta, 1984, Comp. Biochem. Physiol., 77B, 743-747), DNS-GP from chicken ovalbumin was separated into 13 peaks (C1-13) on HPLC. Beta-galactosidase treatment of the DNS-GP resulted in the disappearance of three peaks and the increase of their neighboring peaks. The results indicated that among 13 DNS-GP components from chicken ovalbumin, three (C6,8,11) were bearing galactose residue at the nonreducing terminal and another three (C7,9,12) would be bearing a galacto- sugar chain from each corresponded component.

The use of mannan-Sepharose 4B affinity chromatography for the purification of endo-beta-N-acetylglucosaminidase from Bacillus alvei

In order to facilitate the isolation of endo-beta-N-acetylglucosaminidase for the structural analysis of glycoconjugates, we have isolated a strain of Bacillus alvei which produces a high level of endo-beta-N-acetylglucosaminidase. We have also devised a simple procedure for the purification of endo-beta-N-acetylglucosaminidase from B. alvei using mannan-Sepharose affinity chromatography. By using this method, endo-beta-N-acetylglucosaminidase was purified 3300-fold with 85% yield from the crude enzyme obtained by ammonium sulfate precipitation of the culture medium. The molecular weight of this enzyme was estimated to be about 66 000 by gel filtration. When using (Man)6(GlcNAc)2-Asn-Dns as substrate, the optimal activity occurs at pH 6.5 with Km of 1.9 mM. The action of endo-beta-N-acetylglucosaminidase toward several glycopeptides was also studied.

Occurrence of a new hematoside in the kidney of guinea pig

We have isolated a new hematoside from guinea pig kidney. Like the usual hematoside (II3NeuAc LacCer), isolated from human erythrocytes, this new hematoside contained glucose, galactose, and N-acetylneuraminic acid in an equimolar proportion. By thin-layer chromatography (TLC), however, it migrated faster than the usual hematoside. After mild alkaline hydrolysis the TLC mobility of this ganglioside became identical to that of the usual hematoside. The sialic acid in this ganglioside was susceptible to Clostridial neuraminidase. Based on TLC mobility and the results of periodate oxidation, the sialic acid of the new hematoside was identified as 9-O-acetyl-N-acetylneuraminic acid. Therefore, the structure of this new hematoside is 9-O-Ac-NeuAc alpha 2 leads to 3Gal beta 1 leads to 4GLc beta 1 leads to 1'Cer.

Presence of activator proteins for the enzymic hydrolysis of GM1 and GM2 gangliosides in normal human urine

Normal human urine has been found to contain activator proteins that stimulate the enzymic hydrolysis of GM1 and GM2 gangliosides. These two activators were partially purified by Sephadex G-200 filtration and DEAE-Sephadex A-50 chromatography. The presence of these two activators was assayed by demonstrating the stimulation of the in vitro hydrolysis of GM1 and GM2 gangliosides. As little as 50 ml of urine is sufficient to detect the presence of these two activators. The crude activator preparation from normal urine was also found to stimulate the hydrolysis of galactosylceramide sulfate by arylsulfatase A.

Differentiation of two variants of type-AB GM2-gangliosidosis using chromogenic substrates

Two variants of type-ABGM2-gangliosidosis can be distinguished by using p-nitrophenyl-6-sulfo-2-acetamido-2-deoxy-beta-D-glucopyranoside (PNP-GlcNAc-6-SO4) as substrate. One of the variants is caused by a deficiency of the activator for the hydrolysis of GM2-ganglioside. The beta-hexosaminidase A from this variant has a normal activity toward both PNP-GlcNAc and PNP-GlcNAc-6-SO4. A second variant caused by a defect in the enzyme, beta-hexosaminidase A, exhibits severely attenuated activity toward PNP-GlcNAc-6-SO4 but normal activity toward PNP-GlcNAc.

The protein activator specific for the enzymic hydrolysis of GM2 ganglioside in normal human brain and brains of three types of GM2 gangliosidosis

In order to understand the etiology of Type AB GM2 gangliosidosis, we have purified and characterized the activator protein (GM2 activator) specific for the enzymic hydrolysis of GM ganglioside from normal human brain. The purified activator from human brain moved as one major protein band in various electrophoretic systems. We have also prepared the antiserum against this activator. The levels and the nature of GM2 activator and beta-hexosaminidase A were examined in the brains of five cases of GM2 gangliosidosis-one Type B, two O, and two Type AB. We found that the levels of GM2 activator in both Type B and Type O cases were markedly elevated, and that the two Type AB cases were the results of different causes. One case had a defective beta-hexosaminidase A and an elevated level of GM2 activator. Although this defective beta-hexosaminidase A could hydrolyze synthetic substrates, it was inactive in the cleavage of natural glycosphingolipids in the presence of the GM2 activator. It could, however, hydrolyze asialo-GM2 and GbOse4Cer in the presence of sodium taurodeoxycholate. The other case had normal beta-hexosaminidase A, but had a very low level of GM2 activator when analyzed by in vitro assay, suggesting the deficiency of this activator. By immunoelectrophoresis, this case was found to be completely devoid of the protein that cross-reacts with the antiserum against the GM2 activator.

Carbohydrate structure of human fibrinogen. Use of 300-MHz 1H-NMR to characterize glycosidase-treated glycopeptides

The carbohydrate composition of fibrinogen and constituent S-carboxymethylated chains was determined. All the carbohydrate on the parent molecule could be accounted for on the B beta and gamma chains. The A alpha chain was found to be devoid of carbohydrate. Glycopeptides were prepared from fibrinogen, B beta, and gamma chains by pronase digestion and subsequent chromatography on Sephadex G-50. The 300-MHz 1H-NMR spectra of glycopeptides from all three sources were consistent with biantennary type oligosaccharide chains. The glycopeptides resulting from exoglycosidase digestions were examined with 300-MHz 1H-NMR spectroscopy, and the changes in the signals caused by selective removal of sugar residues were studied. This technique enabled us to assign each anomeric proton to the corresponding monosaccharide unit independent of previous work. Our results indicate that fibrinogen glycopeptides are of the biantennary type, and are in complete agreement with the previously reported peak assignments (Vliegenthart, J. F. G., van Halbeek, H., and Dorland, L. (1981) Pure Appl. Chemn. 53, 45-77). Affinity chromatography of the glycopeptides on concanavalin A-Sepharose also showed that the glycopeptides from fibrinogen are greater than 95% biantennary oligosaccharide chains. Based on carbohydrate composition, 1H-NMR spectroscopy, sequential exoglycosidase digestion, and gas chromatography-mass spectrometry of derived partially methylated alditol acetates, we propose that fibrinogen contains four oligosaccharide chains of the structure shown below. (formula, see text)

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).