Serum cholesterol, its lipoprotein fractions among survivors of cerebrovascular disease. A case-control study

A case-control study was conducted in 1983 on 210 cerebrovascular disease (CVD) patients identified from a retrospective cross-sectional door-to-door survey of four cities in the People's Republic of China. One hundred and eleven male (mean age 63.8 +/- 8.9 years) and 99 female (mean age 63.5 +/- 11.1 years) CVD survivors and controls matched for sex, age, race and area were selected. Total serum cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol were measured to see if there were differences between lipids in survivors of CVD and their matched controls. There was a higher level of total cholesterol in cerebral thrombotic patients (n = 114) and a lower level of total cholesterol and high-density lipoprotein cholesterol in cerebral hemorrhagic patients (n = 35) than in controls, although the results were not statistically significant. The only higher level of total serum cholesterol that might be important was in the group of male thrombotic patients of age greater than 70 years (n = 22; nominal p value less than 0.05). The implication of this finding needs further clarification.

Virulence of wild-type E. coli uroisolates in experimental pyelonephritis

This study was designed to analyze the colonizing and invasive properties of wild-type bacteriuric E. coli possessing a variety of phenotypic characteristics in experimental nonobstructive pyelonephritis (P and Type 1 [T] fimbriae, hemolysin [Hly], presence of K capsules, flagella [H], serotype, biotype, human and mouse serumcidal resistance). Special emphasis was on the role of Gal-Gal adhesin (P fimbriae) of non-genetically engineered uroisolates. It was shown that organisms that are P+ or T+ or Hly+ are more likely to colonize bladders than strains negative for those parameters (P less than 0.001). Additionally, P+ strains were more often associated with kidney histopathology than P- E. coli (P less than 0.05). However, the data also indicated that fimbriae (P and Type 1) were not sole determinants of virulence since two strains devoid of fimbriae, hemolysin, K capsules and sensitive to human serumcidal activity caused incipient and acute pyelonephritis. Even among identical serotypes and biotypes, the presence/absence of fimbriae did not appear to be the critical factor in urovirulence, nor did the presence of several positive characteristics (hemolysin, K capsule, flagella, serum resistance) in a given strain enhance uropathogenicity. Therefore, these properties do not need to work together to render an E. coli urovirulent. These phenotypic characters may simply represent associated or serologic markers with the host serving as the dominant determinant of susceptibility to urinary infection. The findings emphasize the inherent limitations in relating and extrapolating colonizing and invasive properties of genetically engineered strains to those of naturally occurring, wild-type E. coli human uroisolates causing pyelonephritis.

Characterization of a nonspecific activator protein for the enzymatic hydrolysis of glycolipids

We have studied the substrate specificities of a non-specific activator protein on the enzymatic hydrolyses of the following compounds: GM1 and GM2, as well as several of their derivatives including oligosaccharides, GgOse3Cer-II3-sulfate and LacCer-II3-sulfate, Gb-Ose3Cer and GbOse4Cer, three neolacto-series glycosphingolipids, and two non-ceramide glycolipids. Our results show that this activator protein has a broad spectrum of activity and exhibits the properties of a nonspecific natural detergent. The evidence of non-specificity was the ability of this activator protein to stimulate the hydrolyses of glycolipids, regardless of glycosphingolipids or non-ceramide glycolipids, carried out by glycosidases from animals, plants, and microorganisms. Its activity was, however, limited to substrates that had a lipid moiety. The oligosaccharide of GM1 and deacetyl-fatty acid free GM1 (II3-NeuGg-Ose4-sphingosine) were hydrolyzed by beta-galactosidase in the absence of this activator protein.

Gangliosides GM2, IV4GalNAcGM1b, and IV4GalNAcGC1a as antigens for monoclonal immunoglobulin M in neuropathy associated with gammopathy

It was previously reported that monoclonal IgM from two patients with gammopathy and neuropathy showed similar specificity by reacting with the same group of unidentified minor components in the ganglioside fractions of human nervous tissues (Ilyas, A. A., Quarles, R. H., Dalakas, M. C., and Brady, R. O. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 6697-6700). Enzymatic degradation, ion-exchange chromatography, and immunostaining of purified ganglioside standards on thin-layer chromatograms have now revealed that the antigenic glycolipids recognized by the IgM from these patients are gangliosides GalNAc beta 1-4Gal(3-2 alpha NeuAc)beta 1-4Glc beta 1-1Cer(GM2), GalNAc beta 1-4Gal(3-2 alpha NeuAc)beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1-1Cer (IV4GalNAcGM1b), and GalNAc beta 1-4Gal(3-2 alpha NeuAc)beta 1-3GalNAc beta 1-4 beta Gal(3-2 alpha NeuAc)beta 1-4Glc beta 1-1-Cer (IV4GalNAcGD1a). The monoclonal IgM appears to be reacting with the terminal [GalNAc beta 1-4Gal(3-2 alpha NeuAc)beta 1-] moiety shared by these three gangliosides and is a useful probe for detecting small amounts of GM2, IV4GalNAcGM1b, IV4GalNAcGD1a, and other gangliosides with the same terminal sugar configuration in tissues. Species distribution studies using the antibody revealed that GM2 is present in the brains and nerves of all species examined, while IV4GalNAcGM1b and IV4GalNAcGD1a exhibit some striking species specificity. GM2, but not IV4GalNAcGD1a, is enriched in purified myelin from human brain.

A GM2-specific beta-hexosaminidase from the roe of striped mullet (Mugil cephalus)

The roe of striped mullet (Mugil cephalus) was found to contain a beta-hexosaminidase different from the beta-hexosaminidases isolated from other sources. The enzyme from mullet roe is able to cleave GalNAc from GM2 without the assistance of either an activator protein or a detergent. It also cleaves the oligosaccharide derived from GM2 and other oligosaccharides containing the GM2 sequence GalNAc beta 4(NeuAc alpha 3)Gal-. However, it is not effective in hydrolyzing neutral glycosphingolipids containing terminal GalNAc or GlcNAc, such as GbOse4Cer, GgOse3Cer, or LcOse3Cer. These results indicate that mullet roe beta-hexosaminidase can specifically cleave GalNAc from the glycoconjugates containing the GM2 sequence. No beta-hexosaminidase with such specificity has been previously described. Thus, this unique enzyme should be very useful for the detection and analysis of glycoconjugates containing the oligosaccharide chains with GM2 sequence.

Isolation and characterization of gangliosides with hybrid neolacto-ganglio-type sugar chains

We have previously reported the presence of GM2 as the major ganglioside in the roe of striped mullet, Mugil cephalus, (Li, Y.-T., Hirabayashi, Y., DeGasperi, R., Yu, R. K., Ariga, T., Koerner, T. A. W., and Li, S.-C. (1984) J. Biol. Chem. 259, 8980-8985). In addition to GM2, mullet roe also contain a series of gangliosides with thin-layer chromatographic mobilities slower than GM2. Besides enzymatic hydrolysis and NMR spectroscopy, we have employed the thin-layer chromatography overlay technique using a human monoclonal IgM antibody which recognizes the GM2 epitope to study the nature of these gangliosides. Using these methods we have isolated and characterized three novel mullet roe gangliosides with the following structures: (Formula: see text). These three gangliosides all contain neolacto-series sugar chains. However, the unique feature of gangliosides 5 and 10 is that the terminal portion of the sugar chain is of the ganglio-series while the internal portion is of the neolacto series structure. Due to the substitution of a GalNAc on the internal Gal in 9 and 10 in the inner core, these two gangliosides also contain the gangliotriaosyl structure. Thus, the sugar chains in these gangliosides are of novel type and can be considered a hybrid between the two series which can be defined as the neolacto-ganglio series.

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.

A prevalence survey of 'incapacitating headache' in the People's Republic of China

Two Chinese populations over age 15 were surveyed as to the point prevalence of "incapacitating" headaches in an urban population of 1,525 persons and a rural one of 1,203. Personal interviews were carried out by a team of instructed interviewers; there was 100% cooperation. In both populations, prevalence in women was twice that in men except in the urban population in the youngest age group. Prevalence in the urban was almost exactly twice that of the rural population, with the highest figure occurring in traders.

Brain injury due to head trauma. Epidemiology in urban areas of the People's Republic of China

A door-to-door survey was carried out in six cities of the People's Republic of China during 1983 in a well-defined population of 63,195 to determine the prevalence of frequently occurring neurologic disorders, including brain injury. In the survey, trained health workers conducted a complete census and administered a questionnaire that had been pretested to assure a high level of sensitivity in identifying individuals suffering from brain injury due to head trauma. All those with responses suggesting brain injury were examined by senior neurosurgeons who used uniform diagnostic criteria and reviewed available medical records to establish a diagnosis. There was 100% cooperation with the screening and diagnostic phases of the survey. Based on this investigation, the age-adjusted (to the 1960 US population) prevalence ratio for brain injury due to head trauma is seven per 1,000, and the incidence rate is 56 per 100,000 per year. The ratios and rates are higher in male than female subjects. The main cause of brain injury due to head trauma in the People's Republic of China is bicycle accidents.

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.

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.

Cerebrovascular disease in the People's Republic of China: epidemiologic and clinical features

A door-to-door survey was carried out in six cities of the People's Republic of China (PRC). There was 100% cooperation with the survey. Among 63,195 screened individuals, there were 392 prevalent cases of completed stroke and 115 incidence cases. Prevalence ratios and incidence rates for completed stroke showed a south-to-north gradient. The highest point prevalence ratio and incidence rate (age-adjusted to the 1960 US population) were documented in Harbin in northeast PRC (1,249/100,000; 441/100,000/yr). The majority of new completed strokes were cerebral infarction, but the percentage of intracerebral hemorrhage (44%) was much greater than that reported among Caucasian populations.

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.

Epidemiology of epilepsy in urban areas of the People's Republic of China

To determine the prevalence of major neurologic disorders, a door-to-door survey was conducted in six cities of the People's Republic of China during 1983 in a well-defined population of 63,195. The survey included a complete census and a screening interview together with an examination having high sensitivity for detecting individuals with frequently occurring neurologic disorders, including epilepsy. All individuals with responses or findings suggesting neurologic disease were examined by senior neurologists using standardized diagnostic criteria. There was 100% cooperation among the study subjects. Two hundred eighty-nine individuals alive on prevalence day (January 1, 1983) were identified as having epilepsy, yielding a lifetime age-adjusted (to the 1960 U.S. population) point prevalence ratio of 4.4/1,000. There were 16 people who developed epilepsy in the sample population during 1982, providing an age-adjusted incidence rate of 35/100,000 per year. The most frequent type identified was generalized convulsive seizures. Brain injury, intracranial infection, and cerebrovascular disease, in that order, were the leading putative causes of epilepsy.

A prevalence survey of Parkinson's disease and other movement disorders in the People's Republic of China

A door-to-door survey was conducted in six cities of the People's Republic of China. A total of 63,195 individuals were sampled during 1983 to determine the prevalence of major neurologic disorders. The survey involved a complete census, followed by a pretested interview and brief screening examination with a high level of sensitivity for detecting individuals with frequently occurring neurologic diseases, including movement disorders. Subjects with abnormal responses or findings were examined by a neurologist. There was 100% cooperation among the study subjects. Twenty-eight individuals alive on prevalence day (Jan 1, 1983) were identified as having Parkinson's disease, yielding an age-adjusted (to the 1960 US population) prevalence ratio of 57 per 100,000 population. All subjects were older than the age of 50 years. After the fifth decade of life, the age-specific prevalence ratios increased with age.

Glycosphingolipids in insects. Chemical structures of ceramide tetra-, penta-, hexa-, and heptasaccharides from Calliphora vicina pupae (Insecta: Diptera)

Four neutal fraction glycosphingolipids, designated components 4-7, were purified from the pupae of Calliphora vicina and isolated by the use of high performance liquid chromatography. Their chemical structures were determined to be: GalNAc(beta 1-4)GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)Cer; GalNAc(alpha 1-4)GalNAc(beta 1-4)GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)Cer and Gal(alpha 1-3)GalNAc(beta 1-4)GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)Cer; Gal(beta 1-3)GalNAc(alpha 1-4)GalNAc(beta 1-4)GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)Cer; and GlcNAC(beta 1-3)Gal(beta 1-3)GalNAc(alpha 1-4)GalNAc(beta 1-4)GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)Cer. By the use of specific exoglycosidases, it was possible to assign anomeric configurations to all the sugar residues present. Analysis of the ceramide moiety by electron-impact mass spectrometry revealed the dominant fatty acid and sphingoid to be arachidic acid (C20:0) and tetradecasphing-4-enine, respectively.

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.

Antitermination of E. coli rRNA transcription is caused by a control region segment containing lambda nut-like sequences

We have localized the antitermination system involved in E. coli ribosomal RNA transcription and compared it with antitermination in the lamboid bacteriophages. In vivo experiments with gene-fusion plasmids were used to examine the ability of specific areas of the rrnG control region to convert an ordinary transcription complex into antitermination transcription complex. A 67 bp restriction fragment immediately following the rrnG P2 promoter decreased transcription termination about 50%. This fragment contains box A-, box B-, and box C-like sequences similar to those in lambda nut loci. It also caused transcripts from lac and hybrid trp-lac promoters to read through a transcription terminator. Translation through the 67 bp segment or reversal of its orientation resulted in complete loss of antitermination activity. We conclude that the E. coli ribosomal RNA operons possess an antitermination system similar to that used by the bacteriophage lambda.

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.

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.