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PubMed1994

Synthesis of the Forssman pentasaccharide and terminal tetra-, tri-, and di-saccharide fragments.

The 2-(trimethylsilyl)ethyl (TMSEt) beta-glycosides of the Forssman pentasaccharide [alpha-D-GalNAc-(1-->3)-beta-D-GalNAc-(1-->3)-alpha-D-Gal- (1-->4)-beta-D-Gal-(1-->4)-D-Glc] and the terminal tetrasaccharide, as well as the methyl glycosides 1 and 2 of the terminal di- and tri-saccharides, were synthesised by silver trifluoromethanesulfonate-promoted alpha-glycosylation of suitably protected mono-, di-, tri-, and tetrasaccharide alcohols with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl bromide, followed by removal of protecting groups. The anomeric TMSEt group of the Forssman pentasaccharide and terminal tetrasaccharide was removed with trifluoroacetic acid-dichloromethane, to give the corresponding hemiacetal sugars 4 and 6.

Carbohydrate Sequence↗
PubMed1983

Inhibition of human lymphocyte activation by wheat germ agglutinin: a model for saccharide-specific suppressor factors.

The suppressive effect of wheat germ agglutinin (WGA) on lectin-stimulated blastogenesis and immunoglobulin production was studied. Addition of WGA at 10 micrograms/ml inhibited phytohemagglutinin (PHA)-, concanavalin-A (Con-A)-, and pokeweed mitogen (PWM)-induced mitogenic responses by 70-80%. PWM-driven immunoglobulin synthesis was suppressed by 45% with WGA. The inhibitory effects of WGA were not due to cell death or to interference with lectin binding at the cell surface. Inhibition was dependent on the presence of WGA in the cell culture during the first 24 hr of mitogen exposure and was observed in cultures of both monocyte-depleted peripheral blood mononuclear cells as well as T-cell-enriched populations. WGA-induced inhibition of blastogenesis was blocked by the addition of N-acetylglucosamine (GluNAc) which prevents WGA binding to the cell surface. WGA was found to mimic the suppressive effect of a soluble immune suppressor supernatant (SISS) derived from Con-A-activated mononuclear cell cultures. PHA responses were inhibited by 80 and 95% with SISS and WGA, respectively. The inhibition by both WGA and SISS was totally reversed with addition of GluNAc. Furthermore, WGA and SISS demonstrated competition for the same cell surface receptor site. WGA may therefore be useful as an in vitro model of a saccharide-specific, biologically relevant, soluble mediator for the investigation of mechanisms of immunologic suppression.

Cells, Cultured↗
PubMed1986

Primary structure of a major sialyl-saccharide alditol from human amniotic mucins expressing the tumor-associated sialyl-X antigenic determinant.

A major sialyl-saccharide alditol isolated from mucins of human amniotic fluid was purified by high-performance liquid chromatography followed by high-performance thin-layer chromatography of the methylated derivative and subjected to structural analyses which comprised fast atom bombardment and electron impact-mass spectrometry, methylation analysis, exoglycosidase digestion and CrO3 oxidation. The structure of a disialylated pentasaccharide characterized by a sialyl-X antigenic determinant was established: (formula; see text)

Amniotic Fluid↗
PubMed1996

Development of protamine-bonded phase for separation of saccharides in liquid chromatography.

A protamine-bonded polymer gel was synthesized by passing this protein through an activated carbamate polyamine polymer gel layer. This new packing material was suitable for versatile separation of monosaccharides, oligosaccharides, sugar alcohols and uronic acids in liquid chromatography. The column packed with this gel could be operated at room temperature and gave excellent recovery for the reducing monosaccharides such as 2-deoxyribose, 2-deoxyglucose, ribose and mannose for which the conventional alkylamine-bonded phase column gave poor recovery. This column was used for the analysis of saccharides in urine using a post-column reaction detection system.

Amino Acid Sequence↗
PubMed1975

Electron microscopic demonstration of a saccharide moieties in the hypophase of the alveolar surfactant system.

For electron microscopic demonstration of complex carbohydrates and simple sugars in the mouse lung, anionic dye and lectins were used. After immersion fixation of small lung tissue blocks, the alveolar surfactant system was destroyed and only membrane bound carbohydrates (cell coat) could be demonstrated by means of colloidal iron and ruthenium red. Fixation of the whole lung via the visceral pleura preserved the alveolar surfactant system. Only this technique afforded a distinction between cell coat components and hypophase components. After performance of the Concanavalin A-peroxidase technique and after incubation in ferritin-labed Concanavalin A, Lens culinaris lectin or Ricinus communis lectin, various saccharide moieties were demonstrable by immune electron microscopy in the hypophase of the alveolar surfactant system.

Animals↗
PubMed1988

Influence of saccharides and sodium chloride on growth and differentiation of Trypanosoma cruzi.

The influence of saccharides, especially glucose and fructose, on the metacyclogenesis and growth of Trypanosoma cruzi has been investigated. In the absence of glucose and fructose in the media, both the percentage of metacyclic forms and the growth increased significantly. Furthermore, the addition of NaCl to the medium without monosaccharides strongly increased the formation of metacyclic forms. Presence of NaCl and absence of monosaccharides showed a synergic effect on differentiation of T. cruzi.

Animals↗
PubMed1986

Characterization of dolichol monophosphate- and dolichol diphosphate-linked saccharides in trypanosomatid flagellates.

Dolichol-P- and dolichol-P-P-linked saccharides were isolated from several trypanosomatid flagellates incubated with [U-14C]glucose. Formation of Glc-P-dolichol and Man-P-dolichol was observed in Herpetomonas muscarum and Leishmania adleri, whereas only the latter derivative was synthesized in Trypanosoma dionisii and Leptomonas samueli. The main and largest dolichol-P-P-linked oligosaccharide formed in Trypanosoma conorhini, T. dionisii, L. samueli, Herpetomonas samuelpessoai and H. muscarum appeared to be Man9GlcNAc2, whereas in Blastocrithidia culicis it was Man6GlcNAc2. In L. adleri there were two main oligosaccharides linked to dolichol-P-P, Man6GlcNAc2 and Man5GlcNAc2. The The structures of the oligosaccharides were identical with those of the intermediates in the formation of Glc3Man9GlcNAc2-P-P-dolichol in higher eucaryotes. It was concluded that similarly to Trypanosoma cruzi, Crithidia fasciculata and Leishmania mexicana, no glucosylated derivatives of dolichol-P-P were formed in the additional seven trypanosomatids studied here. The results obtained suggest that the defective step could be in some cases the formation of Glc-P-dolichol and in others, the transfer of glucose residues from the latter compound to dolichol-P-P-linked oligosaccharides.

Acetates↗
PubMed1983

Thermodynamics of binding between saccharides and Helix pomatia A hemagglutinin.

Binding constants for the interactions between Helix pomatia A hemagglutinin and the following saccharides were estimated at pH 7.0 and 25 degree C, using the circular dichroism method: N-acetyl-D-galactosamine, 5700 M-1; N-acetyl-D-glucosamine, 1000 M-1; melibiose, 86 M-1; raffinose, 350 M-1. The binding of N-acetyl-D-galactosamine to Helix pomatia A hemagglutinin was investigated in detail, using the circular dichroism and fluorescence methods, over the temperature range 5-50 degree C and pH range 7.0-2.5. The thermodynamic parameters, delta H degree (kcal . mol-1), delta G degree (kcal . mol-1), and delta S degree (e.u.), for this binding reaction at 25 degrees C were estimated as follows: -11.3, -5.24, -20.3 at pH 7.0; -9.1, -5.71, -11.2 at pH 4.5; -38.3, -3.19, -118 at pH 2.5. The negative values of delta H degrees and delta S degrees at pH 2.5 were especially large. This may be related to the restoration of the Helix pomatia A hemagglutinin molecule or its binding site from an unstable configuration caused by lowering the pH of the reaction medium to the original configuration of the presence of N-acetyl-D-galactosamine.

Animals↗
PubMed1993

Activation of enzymes in organic media at low water activity by polyols and saccharides.

Horse liver alcohol dehydrogenase and alpha-chymotrypsin were deposited on a porous support material, Celite. After equilibration at a well-defined water activity, the catalytic activity was measured with diisopropyl ether as reaction medium. The effects of the presence of polyols and simple saccharides in the preparations were investigated. The additives caused a considerable increase in the amount of water bound to the preparation at a fixed water activity. At low water activities the catalytic activity was increased and at high water activity it was decreased by the additives. The presence of additives increased the ratio of alcoholysis-to-hydrolysis activity of chymotrypsin.

Alcohol Dehydrogenase↗
PubMed1992

Binding of endotoxin to macrophages; interactions of spin-labelled saccharide residues.

The molecular mechanisms of endotoxin action are poorly understood. A prerequisite to cellular activation by this agent must be interaction (binding) with the plasma membrane. In this study we have investigated the role of the polysaccharide region of endotoxin (LPS) in binding to macrophages and macrophage-like cell lines. The LPS molecules, from Escherichia coli O111.B4, J5 and the lipid-A, were spin labelled with 2,2,6,6-tetramethylpiperidine-N-oxyl] (Tempo) free radical in their sugar residues, and examined by electron spin resonance spectroscopy. This is the first report of the synthesis of spin-labelled endotoxins. Measurement of the rotational correlation times (Tc) indicated that the saccharide resides do not bind to membrane surface structures and suggests that the binding of LPS to macrophages is mediated by the lipid acyl chains. Anti-sera to LPS from E. coli O111.B4 was effective in binding to the polysaccharide of the same LPS bound to the cell surface.

Animals↗
PubMed1987

The mono- and difucosyl blood group B glycosphingolipids of rat large intestine differ in type of core saccharide.

Two blood group B-active glycosphingolipids were isolated from rat large intestine and characterized by mass spectrometry, proton NMR spectroscopy and methylation analysis. The following structures were concluded: Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer and Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer. The two glycolipids thus differ in their core saccharides (type 1 and type 2 chain, respectively) and therefore must have different pathways for biosynthesis.

ABO Blood-Group System↗
PubMed1989

The barrier function of the outer membrane of Pseudomonas maltophilia in the diffusion of saccharides and beta-lactam antibiotics.

This paper reports that the efficiency of solute diffusion through the outer membrane of Pseudomonas maltophilia is roughly 3 to 5% of that of Escherichia coli. This is despite the fact that the outer membrane pore(s) is only a little smaller than that of E. coli. These results suggest that P. maltophilia has a low copy number of porin(s). The outer membrane of antibiotic resistant clinical isolates showed even less efficient permeability towards saccharides and antibiotics than the laboratory strains.

Anti-Bacterial Agents↗
PubMed1993

Enhancement of mitral regurgitation and normal left atrial color Doppler flow signals with peripheral venous injection of a saccharide-based contrast agent.

OBJECTIVES: The saccharide ultrasound contrast agent SHU 508 A was used to test the hypothesis that an intravenous, transpulmonary contrast method can enhance color Doppler flow signals in the left atrium in a clinically useful manner. BACKGROUND: Color Doppler display of mitral regurgitation may be unreliable because of variable signal to noise ratios that are at times poor. Traditional contrast agents enhance color Doppler flow signals in the right heart chambers. This study describes our observation of a recently developed contrast agent, SHU 508 A, capable of pulmonary transit after peripheral venous injection. METHODS: Control subjects (n = 10) and patients with suspected mitral regurgitation (n = 23) were studied by color Doppler flow imaging before and after 3-g intravenous doses of SHU 508 A. Reference grading of mitral regurgitation (0 to 3) was formulated from left ventricular angiography. In the four-chamber view of the left atrium, we selected for analysis the systolic frame with the maximal retrograde jet of mitral regurgitation (aliased/blue) and the diastolic frame with the maximal color coding from anterograde pulmonary venous flow (red) for planimetry and for grading the intensity of the color Doppler signal (0 to 5). RESULTS: The score of the color Doppler signal intensity increased by > or = 2.5 after 3 g of SHU 508 A (p < 0.001). Flow detection improved, as shown by the increased jet area of mitral regurgitation (> or = 170%), after 3 g of SHU 508 A (3 +/- 3 vs. 12 +/- 8 cm2, p < 0.001) and by a > or = 200% increase in normal anterograde flow area (p < 0.001) in both the mitral regurgitation group and the control group. After contrast enhancement, the correlation between angiographic grading and the relation of jet area to the left atrial area increased from r = 0.79 to r = 0.91. CONCLUSIONS: Contrast-mediated increased echogenicity of the left atrial blood pool improves the signal to noise ratio of Doppler images of mitral regurgitation and anterograde atrial flow. The technique is safe and simple and seems to minimize variability due to instrument design and anatomic signal attenuation.

Adult↗
PubMed1991

Studies of the permeability of isolated porcine peritoneum to nutrients: saccharides.

Isolated peritoneal membrane, freshly harvested from pigs, was studied in vitro to determine the permeability of the membrane to saccharide nutrients. Studies were performed with glucose and sucrose at various transmembrane gradients ranging from 150 to 600 mosm/liter (mmol/liter) and with polysaccharide at a 300 mosm/liter gradient. Findings indicate that flux of these nutrients across the isolated peritoneum is related to molecular weight and that sufficient kilocalories will traverse the membrane to provide for adequate carbohydrate nutrition (calculated to deliver more than 3000 kcal/day at gradients of 150 mosm/liter). Polysaccharide flux studies suggest that carbohydrate calories may be provided in the form of complex molecules and not only in the form of glucose. Studies of 1:1 serum and polysaccharide mixtures showed the conversion of polysaccharide to glucose by serum in vitro. When rats were given intraperitoneal polysaccharide their blood glucose levels rose promptly although they remained fasting, suggesting an in vivo conversion also occurs. These findings provide support for use of polysaccharides intraperitoneally as means to reduce the osmolarity of fluid administered for nutritional support; this would increase tolerance while still providing ample calories. The in vitro apparatus used in these studies provides a mechanism to study individual nutrients and yields highly reproducible results. These studies add further evidence that intraperitoneal nutrition is feasible.

Animals↗
PubMed2005

Determination of saccharide content in pneumococcal polysaccharides and conjugate vaccines by GC-MSD.

A simple and sensitive gas chromatographic method was designed for quantitative analysis of Streptococcus pneumoniae capsular polysaccharides, activated polysaccharides, and polysaccharide conjugates. Pneumococcal serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F polysaccharide or conjugate were subjected to methanolysis in 3N hydrochloric acid in methanol followed by re-N-acetylation and trimethylsilylation. Derivatized samples were chromatographed and detected using gas chromatography with mass selective detector. Gas chromatographic results were compared with colorimetric values with agreement of 92 to 123% over the range of all samples tested. Monosaccharides released during methanolysis included hexoses, uronic acids, 6-deoxy-hexoses, amino sugars, and alditols. Quantitative recovery of monosaccharides was achieved for all serotypes by the use of a single methanolysis, derivatization, and chromatography procedure. Response factors generated from authentic monosaccharide standards were used for quantitation of pneumococcal polysaccharides and conjugates with confirmation of peak assignments by retention time and mass spectral analysis. This method allows saccharide quantitation in multivalent pneumococcal vaccine intermediates and final drug products with low-level detection (10 pg) and peak purity.

Carbohydrate Sequence↗
PubMedDate not supplied

Effects of polyvalency of glycotopes and natural modifications of human blood group ABH/Lewis sugars at the Galbeta1-terminated core saccharides on the binding of domain-I of recombinant tandem-repeat-type galectin-4 from rat gastrointestinal tract (G4-N).

In our recent publication, we defined core aspects of the carbohydrate specificity of domain-I of recombinant tandem-repeat-type galectin-4 from rat gastrointestinal tract (G4-N), especially its potent interaction with the linear tetrasaccharide Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc (Ibeta1-3L). The assumed role of galectin-4 as a microvillar raft stabilizer/organizer and as a malignancy-associated factor in hepatocellular and gastrointestinal carcinomas called for further refinement of its binding specificity. Thus, the effects of polyvalency of glycotopes and natural modifications of human blood group ABH/Lewis sugars at the terminal Galbeta1-core saccharides were thoroughly examined by the enzyme-linked lectinosorbent and lectin-glycan inhibition assays. The results indicate that (a) a high-density of polyvalent Galbeta1-3/4GlcNAc (I/II), Galbeta1-3GalNAc (T) and/or GalNAcalpha1-Ser/Thr (Tn) strongly favors G4-N/glycoform binding. These glycans were up to 2.3 x 10(6), 1.4 x 10(6), 8.8 x 10(5), and 1.4 x 10(5) more active than Gal, GalNAc, monomeric I/II and T, respectively; (b) while lFuc is a poor inhibitor, its presence as alpha1-2 linked to terminal Galbeta1-containing oligosaccharides, such as H active Ibeta1-3L, markedly enhances the reactivities of these ligands; (c) when blood group A (GalNAcalpha1-) or B (Galalpha1-) determinants are attached to terminal Galbeta1-3/4GlcNAc (or Glc) oligosaccharides, the reactivities are also increased; (d) with lFucalpha1-3/4 linked to sub-terminal GlcNAc, the reactivities of these haptens are reduced; and (e) short chain Le(a)/Le(x)/Le(y) and the short chains of sialyl Le(a)/Le(x) are poor inhibitors. These distinct binding features of G4-N establish the important concept of affinity enhancement by high density polyvalencies of glycotopes (vs. multi-antennary I/II) and by introduction of an ABH key sugar to Galbeta1-terminated core glycotopes. The polyvalent ligand binding properties of G4-N may help our understanding of its crucial role for cell membrane raft stability and provide salient information for the optimal design of blocking substances such as anti-tumoral glycodendrimers.

ABO Blood-Group System↗
PubMed2004

Regiospecific alkaline protease-catalyzed divinyl acyl transesterifications of primary hydroxyl groups of mono- and di-saccharides in pyridine.

This paper describes highly selective transesterification reactions, catalyzed by an alkaline protease from Bacillus subtilis in pyridine, of several mono- and di-saccharides with divinyl dicarboxylates ranging from 4 to 10 carbon atoms. A series of polymerizable vinyl fatty acid sugar esters were obtained with good selectivity and high yields. Most products had high proportions of the alpha anomer. The influences of the enzymes, solvents, temperature, and acyl donor chain length on the reaction were studied. Vinyl sugar esters offer a new family of functional water-soluble monomers for preparation of sugar-containing polymers.

Bacillus subtilis↗
PubMed2005

Effect of saccharide length on the immunogenicity of neoglycoconjugates from synthetic fragments of the O-SP of Vibrio cholerae O1, serotype Ogawa.

A synthetic hexasaccharide, identical to the terminal hexasaccharide of Ogawa LPS, coupled to bovine serum albumin induced protective antibodies in mice. To determine if there was a minimum saccharide length required for immunogenicity and efficacy, shorter (mono- to pentasaccharide) neoglycoconjugates (CHO-BSA) were tested in mice. The Ogawa CHO-BSA was inoculated at either a constant mass but differing moles, or equal moles but differing masses. Humoral responses were essentially the same when mice received 9 microg of the carbohydrate (0.007 mM with the pentasaccharide) in each of the neoglycoconjugates prepared from mono- through the pentasaccharide, or the same molar amount (0.007 mM), proportionally less by weight when going from the penta- to the monosaccharide. These data show that, within this dose range, the responses occurred virtually independently of the amount of immunogen. Humoral antibodies induced by these immunogens were generally not vibriocidal. Selected antisera induced by CHO-BSA immunogens were protective, but the ELISA titers of the sera were not predictive of the protective capacity. Purified, Ogawa LPS induced anti-Ogawa LPS IgM antibody titers similar to those induced by the Ogawa CHO-BSA conjugates. The anti-whole LPS sera were strongly vibriocidal, as were the previously reported sera induced by hexasaccharide conjugates. This suggests either that the shorter oligosaccharides lack a conformational epitope provided by the hexasaccharide or that the LPS has additional B cell epitopes or selects different B cells in the primary response.

Animals↗