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PubMed1994

Isolation and structural characterization of beta-D-glucosyluronic acid and 4-O-methyl beta-D-glucosyluronic acid-containing oligosaccharides from the cell-wall pectic polysaccharide, rhamnogalacturonan I.

Rhamnogalacturonan I (RG-I), a pectic polysaccharide isolated from the walls of suspension-cultured sycamore cells, was shown by glycosyl-residue composition analysis to contain D-glucosyluronic acid (GlcpA) residues (1 mol%) and 4-O-methyl-D-glucosyluronic acid (4-O-Me-GlcpA) residues (0.5 mol%). These monosaccharides were shown, by glycosyl-linkage analysis, to be present in RG-I as terminal nonreducing residues. The glycosyl sequences containing GlcpA and 4-O-Me-GlcpA were determined by structurally characterizing the acidic oligosaccharides released by partial acid hydrolysis of RG-I. Six acidic oligosaccharides were purified by semipreparative high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and characterized by glycosyl-residue and glycosyl-linkage composition analyses, GLC-CIMS, GLC-EIMS, electrospray MS (ESMS), and 1H NMR spectroscopy. We propose that three of the acidic oligosaccharides characterized, 4-O-Me-beta-D-GlcpA-(1-->6)-D-Gal, beta-D-GlcpA-(1-->6)-D-Gal, and beta-D-GlcpA-(1-->4)-D-Gal, originate from the galactosyl-containing side chains of RG-I. The three other acidic oligosaccharides characterized, alpha-D-GalpA-(1-->2)-L-Rha, alpha-D-GalpA-(1-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalpA+ ++-(1-->2)-alpha-L-Rha, and alpha-D-GalpA-(1-->2)-alpha-L-Rhap-(1-->4)-alpha-D-GalpA+ ++-(1-->2)-alpha-L- Rhap-(1-->4)-alpha-D-GalpA-(1-->2)-alpha-L-Rha, were generated by partial hydrolysis of the RG-I backbone. No evidence was obtained for the presence of galactosyluronic acid in the side chains of RG-I.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Sequence↗
PubMed1983

Studies on the composition of urinary glycosaminoglycans and oligosaccharides in patients with mucopolysaccharidoses who were receiving fibroblast transplants.

This communication reports studies on the composition of the urinary glycosaminoglycans and oligosaccharides in mucopolysaccharidosis patients who were being treated by fibroblast transplantation. The urinary glycosaminoglycans were precipitated with 9-aminoacridine, the oligosaccharides remaining in solution. Both fractions were further subfractionated by gel filtration. The glycosaminoglycan subfractions were examined for their content of iduronic acid, glucuronic acid, galactosamine and glucosamine. We found no changes in these parameters in a patient who had been treated by repeated fibroblast transplantations over the course of 4 1/2 years. The amino sugar composition of the oligosaccharide fraction was examined and shown to be unchanged. We also found no changes in the degree of sulphation of the urinary glycosaminoglycans specifically related to the transplant in four patients with Hurler disease and two with Hunter disease. We conclude that fibroblast transplantation does not produce detectable changes in the carbohydrate content or degree of sulphation of the urinary glycosaminoglycans and oligosaccharides.

Child↗
PubMed1991

Two-dimensional mapping by high-performance liquid chromatography of pyridylamino oligosaccharides from various glycosphingolipids.

A method to map sugars two-dimensionally for the analysis of the structures of oligosaccharides from glycosphingolipids is described. Nine neutral and ten acidic oligosaccharides were obtained from glycosphingolipids by endoglycoceramidase digestion and labelled with 2-aminopyridine. The pyridylamino oligosaccharides were clearly separated by high-performance liquid chromatography on commercially available C18-silica and amide-silica column. All compounds tested were mapped without any overlapping. The separation of the pyridylamino oligosaccharides on the C18-silica column depended on the numbers and positions of sialic acid and N-acetylhexosamine residues; on the amide-silica column, the separation depended on the total number of sugar residues.

Carbohydrate Conformation↗
PubMed1991

Separation of fluorescent oligosaccharide derivatives by microcolumn techniques based on electrophoresis and liquid chromatography.

Various aldose oligosaccharides can be quantitatively derivatized into primary amines for subsequent reaction with fluorogenic reagents, such as 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde or 3-benzoyl-2-naphthaldehyde. Capillary electrophoresis (CE) and microcolumn liquid chromatography (LC), coupled with laser-induced fluorescence detection, were evaluated as a means of separating complex oligosaccharide mixtures. Whereas microcolumn LC and open-tubular CE appear confined in their utility to relatively small oligosaccharides, unprecedented results were obtained with polyacrylamide gel-filled capillaries on hydrolyzed malto-oligosaccharides and enzymatically degraded samples of chondroitin sulfate and hyaluronic acid.

Chromatography, Liquid↗
PubMed1995

Purification of preparative quantities of group B Streptococcus type III oligosaccharides.

Many bacterial capsular polysaccharides are regularly repeating units of oligosaccharides. Bacterial oligosaccharides have been used in neoglycoconjugate vaccines and as reagents in the study of specific antibody binding. Unfortunately, separation methods have not been adequate for the purification of preparative quantities of bacterial oligosaccharides. Here we describe a size-exclusion procedure that resulted in the resolution of group B Streptococcus type III oligosaccharides composed of 4-25 sugars.

Carbohydrate Sequence↗
PubMed1984

Studies with inhibitors of oligosaccharide processing indicate a functional role for complex sugars in the transport and proteolysis of Friend mink cell focus-inducing murine leukemia virus envelope proteins.

The functions of asparagine-linked oligosaccharides on the PrENV protein of Friend mink cell focus-inducing (FrMCF-1) murine leukemia virus were investigated by examining the effect of two inhibitors of different stages of the biosynthetic pathway of these sugar substituents on the synthesis and processing of the viral proteins. Treatment of virus-producing cells with tunicamycin totally inhibited the glycosylation of PrEnv, and resulted in the formation of a nonglycosylated form of the protein of molecular weight 62 kDa. This component was not proteolytically processed inside the cells, and neither it nor any derivative proteins were incorporated into extracellular virions. Treatment of cells with 1-deoxynojirimycin (DNM), which inhibits the cellular glucosidases normally involved in removal of the three glucose residues present on the initially transferred oligosaccharide chains, resulted in the intracellular accumulation of a slightly larger than normal form of PrENV, and decreased levels of cell-associated gp70. Only gp70 was detected on the cell surface. The bulk of the gp70 produced in the presence of the drug was aberrantly glycosylated, and contained decreased levels of complex and increased numbers of high mannose oligosaccharides; almost all of the gp70 molecules however, contained at least one complex sugar chain. Decreased incorporation of both env and gag proteins into extracellular virions was observed, despite the fact that the gag proteins were processed normally intracellularly; in contrast, DNM treatment of Gazdar murine sarcoma virus-infected HTG2 cells, which produce only gag but not env proteins, did not inhibit the release of extracellular virus. Ultrastructural examination of FrMCF-infected cells treated with DNM indicated the presence of large numbers of intracytoplasmic vacuoles, many of which contained viral particles. These studies indicate that the normal maturation process involved in the formation of complex oligosaccharides is necessary to obtain efficient transport to the plasma membrane and proteolysis of PrEnv, and also provide evidence suggesting a role for the env proteins in regulating assembly of gag proteins into virions.

1-Deoxynojirimycin↗
PubMed1988

Cell surface oligosaccharide modulation during differentiation: IV. Normal and transformed cell growth control.

In previous studies it was shown that cell surface oligosaccharide affinity class distributions and binding capacities were down-regulated as normal cells approach senescence. Using a sensitive, amplified, lectin/specific-ligand competition analysis three other growth regulation states were compared to that of cellular senescence. Non-senescent and senescent low-density and contact-induced growth inhibition was compared with neoplastic cell growth control. Non-senescent human fetal lung fibroblasts (IMR-90) down-regulated their mannosyl and galactosyl specificities in response to both low-density and contact-induced growth inhibition. Senescent IMR-90 down-regulate their mannosyl residues in response to contact conditions while they up-regulate their galactosyl residues under the same conditions. Growth-transformed transplantable canine glioma cells did not show density-dependent regulation of their cell surface oligosaccharide structures. Modulation of the CG cells with a specific alpha-mannosidase II inhibitor, Ricinus communis a galactosyl specific lectin, and pokeweed mitogen a cellular differentiating agent resulted in an altered growth phenotype and up-regulation of the mannosyl and galactosyl surface oligosaccharides. These data indicate a controller function for the cell surface oligosaccharides and a general influence on growth control.

Alkaloids↗
PubMed1992

Cell surface oligosaccharide modulation during differentiation: VI. The effect of biomodulation on the senescent and neoplastic cell phenotype.

These investigations test the hypothesis developed previously, that there are biomolecules which control and integrate cellular differentiation. Our specific interest in cellular differentiation lies in the area of what we refer to as basal or primitive cellular differentiation mechanisms. These mechanisms are common to all cells, and are required for simple recognition and growth regulation. We have investigated two models, the IMR-90 human fetal lung fibroblast model as a representative of normal growth control, and the CG model, canine glioma cells, a transplantable growth transformed cell line. These two models represent normal, and aberrant cellular differentiation control. In previous studies we have shown that the arrangement of the cell surface oligosaccharide structure on these cell types are predictive of phenotypic transition. We have developed, and partially characterized a series of BIOMODULATORS (BM) which delay the onset of display of neoplastic cells. Three classes of BIOMODULATOR have been explored; (1) a large molecular weight natural product (25-35 kDa), PokeWeed Mitogen (PWM); (2) a small molecular weight natural product (500 Da) Cellular Activator and Differentiator (CAD) and a number of natural and synthetic analogs; and (3) an indolizidine alkaloid natural product, Swainsonine (Sw) which has a known cellular target (oligosaccharide biosynthesis). Preliminary data is presented which structurally links some of these BIOMODULATORS in terms of their effective stereochemistry. These BIOMODULATORS, when used before PDL 38, prevent the cell surface oligosaccharide display changes typical of morphological senescence and delay their onset to PDL 100 or more. These BIOMODULATORS also appear to have regulatory effects on the neoplastic cell models. This re-regulation results in increases in generation time and an increase in the ability of these cells to be recognized by cytotoxic lymphocytes. Proton NMR linewidth measurements of the fraction of 'bound' water associated with the cellular surface of treated and untreated cell populations showed induced physical changes in the cell surface related to the use of the BIOMODULATOR and correlated to the oligosaccharide display changes. These data were interpreted as indicating an increase in the organizational level of these cells. The data for normal and neoplastic cell populations are compared and contrasted in an effort to form the basis for an analytical approach to the control and integration of differentiation mechanisms.

Animals↗
PubMed1985

O-linked oligosaccharides of mouse egg ZP3 account for its sperm receptor activity.

Previously, we reported that ZP3, one of three different glycoproteins present in the mouse egg's zona pellucida, serves as a sperm receptor. Furthermore, small glycopeptides derived from egg ZP3 retain full sperm receptor activity, suggesting a role for carbohydrate, rather than polypeptide chain in receptor function. Here, we report that removal of O-linked oligosaccharides from ZP3 destroys its sperm receptor activity, whereas removal of N-linked oligosaccharides has no effect. A specific size class of O-linked oligosaccharides, recovered following mild alkaline hydrolysis and reduction of ZP3, is shown to possess sperm receptor activity and to bind to sperm. The results presented strongly suggest that mouse sperm bind to eggs via O-linked oligosaccharides present on ZP3.

Acetylglucosaminidase↗
PubMed1985

Spin labelling of sialic acid and galactose residues on lymphocyte plasma membrane: effects of lectins on oligosaccharide dynamics.

To investigate the behaviour of glycoprotein and glycolipid receptors at the lymphocyte cell surface, a spin label probe has been introduced into either sialic acid or galactose residues on lymphocyte plasma membrane, using specific activation of sugars with periodate or galactose oxidase, followed by reductive amination. The extent of membrane labelling could be controlled by varying the mole ratios of reactants used. Chloroform-methanol extraction of the labelled membranes showed that approximately 17% of the label is bound to glycolipids. A large fraction of the spin label could be released from both sialic acid and galactose-labelled membrane by treatment with pronase, indicating attachment to membrane proteins. Rotational correlation times (tau c) for both labelled sialic acid and galactose residues were in the range 10-13 X 10(-10) sec, indicating a reduction in sugar headgroup mobility at the membrane surface. Isolated lymphocyte membrane glycoproteins spin labelled on galactose residues and reassembled into phospholipid bilayer vesicles showed similar motional characteristics. Prolonged incubation of conc. suspensions of labelled membrane resulted in cleavage of the sialic acid-bound (but not the galactose-bound) label. Binding of several lectins to labelled plasma membrane produced significant immobilization of cell surface oligosaccharides while others had no effect. This differential restriction in oligosaccharide motion following lectin binding appears to be at least partly related to the sugar specificity of the lectin. Binding of wheat germ agglutinin and Ricinus communis agglutinin to sialic acid and galactose-labelled membrane respectively produced a dramatic decrease in oligosaccharide mobility which was reversible on addition of the appropriate sugar inhibitor. The concn dependence of lectin-induced spin label immobilization suggested a cooperative interaction between the lectins and their oligosaccharide receptors. Binding of lectins to the lymphocyte cell surface thus seems to have distinct effects on the dynamic state of glycoproteins and glycolipids within the glycocalyx.

Animals↗
PubMed1982

Lectin affinity chromatography of Sindbis and Rous sarcoma virus glycopeptides and oligosaccharides.

Glycopeptides and endogly cosidase-digested oligosaccharides from [3H]mannose-labeled Rous sarcoma virus and Sinbis virus have been fractionated by lentil lectin-Sepharose and concanavalin A-agarose affinity chromatography and subsequently analyzed by BioGel P-4 gel filtration. Only a specific subset of the Con A-bound asparaginly-oligosaccharides from he two viruses was also bound to lentil lectin, and this freaction apparently represented fucose-containing, diantennary acidic-type structures ((NeuNAc +/- Gal-GlcNAc)2 Man3 -GlcNAc2 (fucose)-ASN). The largest glycopeptides from Rous sarcoma virus were unbound to either Con A or lentil lectin and presumably contained tri- and/or tetra-antennary acidic-type structures ((NeuNAc +/- Gal-GlcNAc)3--4 -Man 3GlcNAc2 (+/- fucose)-ASN). In contrast, the majority of 'hybrid'-type oligosaccharides and essentially all of the neutral oligomannosyl core structures (Man5--9 GlcNAc1 and Man3 GlcNAc1) from the endoglycosidase-digested glycopeptides of both viruses were specifically bound to Con A-agarose, with the largest neutral oligosaccharides (Man7--9GlcNAc1) bound more tightly and less efficiently eluted by alpha-methyl mannoside.

Avian Sarcoma Viruses↗
PubMed1983

Degradation of biogenic oligosaccharides by beta-N-acetyl-glucosaminidase secreted by Entamoeba histolytica.

beta-N-Acetylglucosaminidase secreted by Entamoeba histolytica was extracted from the growth medium by affinity chromatography on CH-Sepharose 4 B coupled to p-aminophenyl-1-thio-beta-2-acetamido-2-deoxyglucopyranoside. The enzyme was further purified by isoelectric focusing, by sequential chromatography on DEAE-cellulose and Sephadex G-150, and by preparative disc gel electrophoresis. Chitobiose (betaGlcNAc1-4GlcNAc) derived from chitin as well as the oligosaccharides betaGlcNAc1-4 betaGlcUA1-3GlcNAc, betaGlcNAc1-4 betaGlcUA1-3 betaGlcAc1-4GlcUA, and betaGlcNAc1-4 betaGlc-UA1-3 betaGlcNAc1-4 betaGlcUA1-3 betaGlcNAc1-4GlcUA derived from hyaluronic acid were tested as potential physiological substrates. All these oligosaccharides are susceptible to action of beta-N-acetylglucosaminidase from E. histolytica. Under identical conditions chitobiose is cleaved 38-48 times faster than hyhyauronate oligosaccharides. No release of N-acetylglucosamine was observed when glycopeptides from ovalbumin were used as substrate. The pH optimum of hydrolase activity was 4.5 when chitobiose was used as substrate. Optimal hydrolysis of aluronate oligosaccharides was observed at pH 3.0 for trisaccharide and pH 2.0 for tetra- and hexasaccharide, respectively. Estimation of molecular weight by means of gel filtration gave values of 75 000. The isoelectric point was 5.02 beta-N-Acetylglucosaminidase from E. histolytica does not act on macromolecular chitin and hyaluronic acid.

Acetylglucosaminidase↗
PubMed1986

Characterization of protein-linked oligosaccharides in trypanosomatid flagellates.

Protein-linked, endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides were isolated from several trypanosomatids incubated with [U-14C]glucose. Structural analysis of the compounds revealed that Man9GlcNAc2 was the oligosaccharide transferred from dolichol-P-P derivatives to proteins in Trypanosoma dionisii, Trypanosoma conorhini, Leptomonas samueli and Herpetomonas samuelpessoai and Man6GlcNAc2 in Blastocrithidia culicis and Leishmania adleri. In all cases, transiently glucosylated compounds were detected: Glc1Man7-9GlcNAc2 in T. dionisii, T. conorhini, L. samueli; Glc1Man9GlcNAc2 in H. samuelpessoai, Glc1Man6GlcNAc2 in B. culicis and Glc1Man6GlcNAc2 and Glc1Man5GlcNAc2 in L. adleri. The mechanism of protein glycosylation in T. dionisii and T. conorhini appeared to be similar to that described before for Trypanosoma cruzi epimastigotes, although some differences were found between the structures of the main isomers of Man7GlcNAc2 and Man8GlcNAc2 present in T. conorhini and T. cruzi. Differences between the mechanisms of glycosylation occurring in Leishmania mexicana and L. adleri were also found: Man6GlcNAc2 in the latter microorganism was demannosylated to Man5GlcNAc2, a step not detected in the former parasite. A novel substituent in N-linked high mannose-type oligosaccharides was found in L. samueli and H. samuelpessoai: galactose in the furanose configuration. In the latter trypanosomatid, Man9GlcNAc2 was demannosylated only to Man8GlcNAc2, whereas in all other parasites in which the same oligosaccharide was transferred to proteins, Man5-7GlcNAc2 were also detected.

Animals↗
PubMed1988

Characterization of the high mannose asparagine-linked oligosaccharides synthesized by Schistosoma mansoni adult male worms.

This report describes the structures of the high-mannose-type N-linked oligosaccharides in glycoproteins synthesized by Schistosoma mansoni adult male worms. Adult male schistosomes were incubated in vitro in media containing either [2-3H]mannose, [6-3H]glucosamine or [6-3H]galactose to allow metabolic radiolabeling of the oligosaccharide moieties of newly synthesized glycoproteins. Glycopeptides were prepared from the radiolabeled glycoproteins by digestion with Pronase and fractionation by chromatography on concanavalin A-Sepharose. Eleven percent of [3H]mannose incorporated into the schistosome glycopeptides was recovered in high mannose-type Asn-linked oligosaccharides which bound to the immobilized lectin. Upon treatment of [3H]mannose-labeled glycopeptide with endo-beta-N-acetylglucosaminidase H, the high mannose-type chains were released and their structures were determined by high performance liquid chromatography, methylation analysis, acetolysis and exoglycosidase digestion. The major species of high mannose-type chains synthesized by S. mansoni adult males have the composition Man7GlcNAc2, Man8GlcNac2 and Man9GlcNA2. Structural analyses indicate that these oligosaccharides are similar to high mannose-type chains synthesized by mammalian cells.

Animals↗
PubMed1995

The presence of complex-type oligosaccharides at the C-terminal domain glycosylation site of some molecules of cruzipain.

Cruzipain is a lysosomal enzyme of the flagellate Trypanosoma cruzi. It has three potential asparagine-glycosylation sites, two in the catalytic domain and one in the C-terminal domain. The latter appeared to have both high mannose- and complex-type oligosaccharides, whereas the catalytic domain only had compounds of the former type. The partial susceptibility of the complex-type compounds to endo-beta-N-acetylglucosaminidase H and their relative mannose and galactose content indicate that they had hybrid/monoantennary and biantennary structures. The same pattern of high mannose-type compounds was found at both domains, thus indicating that in cruzipain molecules having only high mannose-type compounds, all oligosaccharides were equally exposed to processing glycosidases and glycosyltransferases. As heterogenity of the protein C-terminal domain has already been detected, it is suggested that this feature might elicit an increased accessibility to processing enzymes responsible for complex-type oligosaccharide formation in certain cruzipain molecules or, alternatively, that a second glycosylation site with increased accessibility might be present in certain cruzipain molecules. Furthermore, the presence of complex-type oligosaccharides strongly suggests that, as in mammalian cells, T. cruzi lysosomal enzymes traverse the entire Golgi apparatus up to the trans-Golgi cisternae and the trans-Golgi network before reaching lysosomes.

Animals↗
PubMed1991

An FM3A mutant, G258, with a mutation that affects both cell growth and oligosaccharide-lipid synthesis.

I have previously isolated a temperature-sensitive FM3A mutant (G258) defective in asparagine-linked glycosylation. G258 shows not only the temperature sensitivity for cell growth, but also temperature sensitivity for synthesis of oligosaccharide-lipid (Nishikawa, Y. (1984) J. Cell. Physiol. 119, 260-266). In the present study, I isolated revertants for cell growth from G258 cells. All three growth revertants also showed reversion on the synthesis of oligosaccharide-lipid. These results imply that the temperature sensitivity for oligosaccharide-lipid synthesis of G258 couples with the temperature sensitivity for cell growth of the mutant. A possible mechanism of the coupling between impaired oligosaccharide-lipid synthesis and growth arrest of G258 cells at 39 degrees C is discussed.

Animals↗
PubMed1978

Biosynthesis and characterization of large dolichyl diphosphate-linked oligosaccharides in Saccharomyces cerevisiae.

Yeast membranes incorporate radioactivity from GDP[14C]mannose into various glycolipids. These can be separated by thin layer chromatography into at least seven components. The major component has been identified previously as dolichyl monophosphate mannose. Only one additional component is not sensitive to mild alkaline saponification, but is hydrolyzed instead under mild acidic conditions. This latter glycolipid has all the characteristics of a polyprenyl diphosphate oligosaccharide with a sugar moiety of more than 12 hexose units. It runs like dolichyl diphosphate derivatives on a DEAE column and evidence is presented that the lipid moiety is a polyprenol. When radioactive Dol-PP-di-N-acetylchitobiose is incubated with yeast membranes in the presence of non-radioactive GDPmannose a small amount of a larger lipid oligosaccharides is formed besides the previously-described Dol-PP-(GlcNAc)2 mannose. This oligosaccharide has all the properties of the glycolipid described above. Its formation is greatly increased when Triton is omitted from the incubation. Radioactivity of the polyprenyl diphosphate [14C]oligosaccharide is transferred to ethanol-insoluble material, most likely endogenous membrane glycoproteins.

Cell Membrane↗
PubMed1981

Isolation and partial characterization of the oligosaccharide moieties of rat preputial beta-glucuronidase.

The oligosaccharide alditols of rat preputial gland beta-glucuronidase have been isolated by reductive alkaline hydrolysis of the enzyme followed by gel filtration. Since the product was about decasaccharide in size, and as beta-glucuronidase contains about 20 sugar residues per subunit, the enzyme must contain two oligosaccharides per subunit. Two major subfractions were obtained. Chemical and enzymatic studies on the initial oligosaccharide alditol fraction and on the separated subfractions indicated the presence of a mannosyl-chitobiosyl core and permitted formulation of the following structures for the two different oligosaccharide alditols: Man3 leads to alpha [(alpha Man, GlcNAc) leads to Man] leads to beta GlcNAc leads to beta GlcNAc-ol Man 3 leads to 4 leads to alpha[Man2 leads to alpha Man] leads to beta GlcNAc leads to beta GLcNAc-ol.

Animals↗