D-mannose Units Research Articles

A Malonyl-Based Scaffold for Conjugatable Multivalent Carbohydrate-BODIPY Presentations.

A concise synthetic route from methylmalonate to a tetravalent aliphatic scaffold has been developed. The ensuing tetra-tethered derivative is equipped with two hydroxyl groups, as well as orthogonal alkene and alkyne functionalities. The usefulness of the scaffold has been demonstrated with the preparation of two representative multivalent derivatives: (i) a tetravalent compound containing two D-mannose units, one fluorescent boron-dipyrromethene (BODIPY) dye and a suitably functionalized amino acid and (ii) by way of dimerization and saponification, a water-soluble tetramannan derivative containing two fluorescent BODIPY units. Additionally, photophysical measurements conducted on these derivatives support the viability of the herein designed single and double BODIPY-labeled carbohydrate-based clusters as fluorescent markers.

Characterization and antioxidant activity of a novel polysaccharide from Pholidota chinensis Lindl.

A novel polysaccharide (PP) was isolated and purified from Pholidota chinensis Lindl. The structure of PP was investigated by HPLC, IR, NMR, etc. and the antioxidant activity was evaluated by hydroxyl radical and superoxide anion assay. Results showed Pholidota chinensis Lindl. contained 3.35% (dry weight) of polysaccharides. The salt-out assay was better than sevag assay for removing protein from crude polysaccharides. The intrinsic viscosity of PP was 1.55dL/g and its average molecular weight was 45,200Da. The monosaccharide composition analysis showed that PP consisted of mannose only. Spectroscopy analysis revealed that PP was mainly composed of α-1,3 and α-1,4 linked d-mannose units with some 2-O- and 3-O-acetyl groups. Moreover, PP can scavenge superoxide anion and hydroxyl radical in a dose-dependent manner, suggesting that PP may be a potential nature antioxidant and may contribute to the analgesic activity of Pholidota chinensis Lindl.

ChemInform Abstract: C-2 Epimerization of Disaccharides by Calcium(II)-Monoamine Systems. A Direct Synthesis of (1→4)-Linked Disaccharides Having a D- Mannose Unit as a Reducing Terminal.

(1→4)- and (1→6)-linked disaccharides were epimerized at C-2 of the reducing terminal under mild conditions by calcium(II)–N-alkylated monoamine systems. Naturally rare (1→4)-linked heterodisaccharides having a D-mannose unit as a reducing terminal can be prepared in one step from disaccharides having a D-glucose unit which are abundunt in nature.

Characterization of the galactomannans from Parkinsonia aculeata seeds and their application on affinity chromatography

Successive aqueous (10 °C, 25 oC and 80 °C) and alkaline (1M NaOH; 25 °C) extractions of milled Parkinsonia aculeata endosperms gave rise to four galactomannan fractions. These extractions furnished viscous galactomannans with Man:Gal ratios ranging from 3.1:1; 3.7:1; 4.9:1 and 6.1:1 (P1, P2, P3 and P4, respectively). Fraction P1 was used for structural studies by using methylation analysis, periodate oxidation and 13 C-NMR. It showed a linear backbone of β(1→4) linked D-mannose units, to which single α(1→6)-linked D-galactose are attached. This galactomannan has Mw 775700 g/mol and intrinsic viscosity of 558 mL/g. The four fractions and the crude endosperm were treated with epichlorydrin and used as matrix for affinity chromatography. All columns tested showed ability to bind lectin samples. The efficiency is related to the degree and pattern of substitution of galactosyl units on the D-mannan backbone.

STRUCTURAL DETERMINATION AND CHEMICAL MODIFICATIONS OF THE POLYSACCHARIDE FROM SEEDS OF Prosopis chilensis Mol. (Stuntz)

The polysaccharide extracted from Prosopis chilensis seeds in acidic medium showed by total hydrolysis and gas-liquid chromatography analysis of the alditol acetates to be composed of galactose and mannose in the molar ratio 1.0:1.9. Studies by methylation and 1H and13C NMR spectroscopy indicated that the polysaccharide was a galactomannan with a chain of D-mannopyranosyl residues linked b 1 4 which carried alternatively a-D-galactopyranosyl residues at position O-6 of D-mannose units. The chemical modification of the galactomannan by reaction with sodium chloroacetate afforded in 95.3% yield, a derivative which gave a very viscous solution with water. By titration it was determined a carboxymethylation degree of 0.42 indicating that 64% of the alcoholic groups were etherified. Reaction of the galactomannan with TEMPO-NaCl-NaOBr system gave a water soluble polysaccharide. The DEPT 135o NMR spectrum indicated that the primary alcoholic groups of galactopyranosyl and unbranched mannopyranosyl residues were fully oxidised

Biosynthesis of hetero-polysaccharides by Pestalotiopsis microspora from various monosaccharides as carbon source

Pestalotiopsis microspora was cultured in media containing various monosaccharides as a carbon source. It was found that P. microspora metabolizes various monosaccharides and the composition of polysaccharides depends strongly on the monosaccharides used for carbon source. When D-glucose, D-mannose or D-galactose were used as the carbon source, hetero-polysaccharides of similar compositions containing a considerable amount of D-mannose units beside D-glucose units were formed. With D-xylose or N-acetyl- D-glucosamine as the carbon source, hetero-polysaccharides containing large amounts of D-mannose and D-galactose units beside D-glucose units were produced. Cultures with L-arabinose as the carbon source produced almost pure glucan, while with L-rhamnose, the yield and the composition of hetero-polysaccharide is the same as that obtained from the culture with D-glucose as the carbon source. The mechanism of biosynthesis of these hetero-polysaccharides is briefly discussed.

Structural studies on fucoidans from the brown seaweed Sargassum stenophyllum

The brown seaweed Sargassum stenophyllum biosynthesizes two different sets of fucoidans. One of them is characterized by higher percentages of glucuronic acid and fewer sulfate groups, which are situated on different sugar units. α- l-Fucose was the major component but other sugars like β- d-galactose, β- d-mannose, α- d-glucuronic acid, α- d-glucose and β- d-xylose were also in substantial amounts. Fucoidans from the other set contain small amounts of α- d-glucuronic acid and high percentages of sulfate groups, which are concentrated on the fucose residues, with only fucose and galactose as major components. Structural studies of one fucoidan from each set suggest that these products have a general basic structure that has a formal resemblance to that of the fucosylated chondroitin sulfates from the body wall of sea cucumbers, namely, a linear core (formed mainly by (1→6)-β- d-galactose and/or (1→2)-β- d-mannose units) with branched chains of ‘fucans’ (formed by (1→3) and/or (1→4)-α- l-fucose, (1→4)-α- d-glucuronic acid, terminal β- d-xylose and, sometimes, (1→4)-α- d-glucose). In fucoidans from the second set, the ‘core’ is reduced to short galactan chains.

Characterization of a biosurfactant, mannosylerythritol lipid produced from Candida sp. SY16.

One yeast strain, SY16, was selected as a potential producer of a biosurfactant, and identified as a Candida species. A biosurfactant produced from Candida sp. SY16 was purified and confirmed to be a glycolipid. This glycolipid-type biosurfactant lowered the surface tension of water to 29 dyne/cm at critical micelle concentration of 10 mg/l (1.5 x 10(-5) M), and the minimum interfacial tension was 0.1 dyne/cm against kerosene. Thin-layer and high-pressure liquid chromatography studies demonstrated that the glycolipid contained mannosylerythritol as a hydrophilic moiety. The hydrophilic sugar moiety of the biosurfactant was determined to be beta-D-mannopyranosyl-(1-->4)-O-meso-erythritol by nuclear magnetic resonance (NMR) and fast atom bombardment mass-spectroscopy analyses. The hydrophobic moiety, fatty acids, of the biosurfactant was determined to be hexanoic, dodecanoic, tetradecanoic, and tetradecenoic acid by gas chromatography-mass spectroscopy. The structure of the native biosurfactant was determined to be 6-O-acetyl-2,3-di-O-alkanoyl-beta-D-mannopyranosyl-(1-->4)-O-meso- erythritol by NMR analyses. We newly determined that an acetyl group was linked to the C-6 position of the D-mannose unit in the hydrophilic sugar moiety.

Preparation and biological properties of dicarboxy-glucomannan: enzymatic degradation and stimulating activity against cultured macrophages

Recently, it has been reported that some polysaccharides showed interesting biological or immunological activities. Glucomannan (GM) purified from Amorphophallus Konjac is a copolymer of 1,4-linked β- d-glucose and β- d-mannose, which has some mono-residual d-glucose or d-mannose branches at the 3-position of d-mannose units of the main chain. We prepared dicarboxy-gluco-mannan (DC-GM), a carboxylic acid derivative of glucomannan, by IO 4−/ClO 2− oxidation. The number-average molecular weight ( M n) of the DC-GM obtained was about 2·0 × 10 4. The chemical structure of DC-GM was investigated by gaschromatography. It showed high water-solubility and enzymatic degradation behavior by cellulase and β- d-glucosidase. The enzymatic degradation rate of the DC-GM was dependent on the degree of introduction of carboxylic acid group. The immunological enhancement activity of the DC-GM was evaluated in vitro by testing glucose consumption and β- d-glucuronidase activity against cultured macrophages, PMA (phorbol-12-myristate-13-acetate)-differentiated HL-60 ( human promyelocytic leukemia) or U937 ( human monoblast leukemia) cells. The DC-GM showed higher stimulating effects against such cultured macrophages than the other polysaccharide derivatives.

C-2 Epimerization of Disaccharides by Calcium(II)–Monoamine Systems. A Direct Synthesis of (1→4)-Linked Disaccharides Having a D-Mannose Unit as a Reducing Terminal

Abstract (1→4)- and (1→6)-linked disaccharides were epimerized at C-2 of the reducing terminal under mild conditions by calcium(II)–N-alkylated monoamine systems. Naturally rare (1→4)-linked heterodisaccharides having a D-mannose unit as a reducing terminal can be prepared in one step from disaccharides having a D-glucose unit which are abundunt in nature.

The (1 → 3)-linked α- l-fucosyl group of the N-glycans of the Wistaria floribunda lectins is recognized by a rabbit anti-serum

An increasing number of plant glycoproteins have been shown to possess a characteristic N-glycan component containing a β-(1 → 2)-linked d-xylose unit on the core β- d-mannose unit, and an α-(1 → 3)-linked l-fucose unit on the asparagine-linked 2-acetamido-2-deoxy- d-glucose unit. Wistaria floribunda seeds have two distinct lectins; the erythroagglutinin, WFA, and the lymphocyte mitogen, WFM. Earlier studies indicated that both lectins belong to such a class of glycoproteins. We now report the complete structural analysis of Pronase glycopeptides derived from WFA. On the basis of chemical treatment of the glycopeptides, carbohydrates composition and methylation analysis of fluorescein-labeled glycopeptides, and their susceptibility to specific exoglycosidases, the structure of the WFA glycan was found to be, α- d-Man p-(1 → 6)-[β- d-Xyl p-(1 → 2)]-[α- d-Man p(1 → 3)]-β- d-Man p(1 → 4)-β- d-Glc pNAc-[α- l-Fuc p-(1 → 3)]-β- d-Glc p-NAc-(1 → N). Quantitative studies on the interaction of the original fluorescein-labeled glycopeptide and its specific degradation products with a rabbit anti-glycan antibody, developed against WFM, showed that the (1 → 3)-linked α- l-fucose unit is essential for interaction. Loss of the terminal α- d-mannosyl groups resulted in decreased, though detectable binding.

Studies on the glucomannan from Candida utilis. Part III. Immunochemical analysis of the glucomannan from Candida utilis.

A glucomannan isolated from a Candida utilis mutant having a new chemotype was further studied by inhibition of the homologous precipitin reaction with oligosaccharides obtained from the glucomannan by partial acid hydrolysis and controlled acetolysis. Oligosaccharides having at least two consecutive alpha-(1----2)-linked mannose residues at the non-reducing end and gluco-manno-pentasaccharide were effective inhibitors. Thus, it appears that the glucomannan had two groups of antigenic determinants, one corresponding to the side chains of two, three, and four mannose units connected by alpha-(1----2)-linkage, and the other corresponding to a side chain composed of an O-alpha-D-glucopyranosyl-(1----6)-O-alpha-D-mannopyranosyl- (1----2)-O-alpha-D-mannopyranosyl-(1----2)-D-mannose unit. These results support a probable structure of repeating units for the glucomannan presented previously. The relative susceptibility of intersaccharidic linkages to acid hydrolysis in the mannan is discussed.

Plant mucilages. XXXV. Isolation and characterization of a mucous polysaccharide, Hippeastrum-H-glucomannan, from the bulbs of Hippeastrum hybridum.

A mucous polysaccharide, named Hippeastrum-H-glucomannan, was isolated from the bulbs of Hippeastrum hybridum HORT. The final preparation was homogeneous as determined by ultracentrifugal analysis, glass-fiber electrophoresis, and gel chromatography. It was composed of D-mannose and D-glucose in the molar ratio of 5 : 2, and its molecular weight was estimated to be 331000. O-Acetyl groups were identified and their content amounted to 13.2%. They were located at positions 2, 6 of some of the D-mannose units. Methylation and partial acid hydrolysis studies showed that the glucomannan is mainly composed of β-1→4-linked aldohexopyranose residues, and that it contains about eighty-three aldohexose units per six non-reducing groups on average. Both D-mannose and D-glucose units occupy non-reducing terminal positions and branching points linked through position 3.

Plant mucilages. XXXIII. An acetyl-rich mucilage, "lycoris-S-glucomannan," from the bulbs of Lycoris squamigera.

A mucilage, named Lycoris-S-glucomannan, was isolated from the bulbs of Lycoris squamigera MAXIM. The final preparation was homogeneous as determined by ultracentrifugal analysis, glass-fiber electrophoresis, and gel chromatography. It was mainly composed of D-mannose and D-glucose in the molar ratio of 7 : 2, and its molecular weight was estimated to be about 1800000. O-Acetyl groups were identified in the glucomannan and their content amounted to 16.7%. They were located at positions 2, 6 of about half of the D-mannose units. Methylation, periodate oxidation, and partial acid hydrolysis studies showed that the glucomannan is mainly composed of β-1→4 linked aldohexopyranose residues, and that it contains about twenty aldohexose units per three non-reducing groups on average. D-Mannose units occupy all branching points linked through position 3, while both D-mannose and D-glucose units occupy non-reducing terminal positions.

Purification and characterization of a novel exo-beta-mannanase from Aeromonas sp. F-25.

A novel exo-beta-mannanase (1,4-beta-D-mannan mannobiohydrolase) was isolated from the culture fluid of strain No. F-25 of Aeromonas hydrophila subspecies anaerogenes, and purified about 4,000-fold by ammonium sulfate precipitation and successive co.umn chromatographies. The final enzyme preparation appeared to be homogeneous on polyacrylamide gel electrophoresis. The enzyme hydrolyzed the beta-1,4-mannan link in polysaccharides of three or more beta-1,4-linked D-mannose units. The enzyme had a molecular weight of 64,000, pI of 5.9, pH optimum of 6.0, and was stable in a pH region of 5.0 to 8.5 and at temperatures below 45 degrees C. The Km values of the enzyme were 5.1 X 10(-4) M for mannotriose, 2.4 X 10(-4) M for mannotetraose and 1.3 X 10(-4) M for mannopentaose. The enzyme attacked codium and coffee mannans to give only mannobiose. Mannobiosyl- and mannotetraosyl-mannitol were hydrolyzed to produce mannobiose and mannitol, while mannobiose and mannosylmannitol were released from mannotriosylmannitol. The enzyme did not act on mannobiose, p-nitrophenyl-beta-D-mannoside, konjac glucomannan, or guar gum galactomannan. Furthermore, the enzyme catalyzed a transglycosylation reaction.

Plant mucilages. XXXI. An acety-rich mucous polysaccharide, "lycoris-R-glucomannan," from the bulbs of Lycoris radiata.

A mucous polysaccharide, named Lycoris-R-glucomannan, was isolated from the bulbs of Lycoris radiata HERBERT. The final preparation was homogeneous as determined by ultracentrifugal analysis, glass-fiber electrophoresis, and gel chromatography. It was composed of D-mannose and D-glucose in the molar ratio of 12 : 1, and its molecular weight was estimated to be 468000. O-Acetyl groups were identified in the glucomannan and their content amounted to 15.5%. They were located at positions 2, 6 of some of the D-mannose units. Methylation, periodate oxidation, and partial acid hydrolysis studies showed that the glucomannan is mainly composed of β-1→4 linked aldohexopyranose residues, and that it contains about thirteen aldohexose units per three non-reducing groups on average. D-Mannose units occupy non-reducing terminal positions and branching points linked through both positions 3 and 6.

Extracellular polysaccharide of Aspergillus flavus

A crude extracellular polysaccharide was isolated by precipitation with ethanol from the culture medium of Aspergillus flavus, where the sole carbon source was D-galactose; purification afforded a homogeneous water-soluble polysaccharide in 0.05% yield on the weight of the employed carbon source. This polysaccharide had the relative molar weight 55 000 and [α]D22 -4.2° (c 0.5, H2O); upon total hydrolysis it afforded D-mannose and D-galactose in a 1 : 0.44 ratio. The products of hydrolysis of the methylated polysaccharide and also the course of partial acid and enzymic hydrolyses of the polysaccharide showed that the main chain was formed by (1 → 2) β-linked D-mannose units, of which each second, on average, was substituted by monomeric D-galactose units at C(6).

Plant mucilages XXVII. Isolation and characterization of a mucous polysaccharide,"Narcissus-T-glucomannan," from the bulbs of Narcissus tazetta var. chinensis.

A mucous polysaccharide, named Narcissus-T-glucomannan, was isolated from the bulbs of Narcissus tazetta L. var. chinensis ROEMER. The final preparation was homogeneous as determined by ultracentrifugal analysis, glass-fiber electrophoresis, and gel chromatography. It was composed of D-mannose and D-glucose in the molar ratio of 5 : 1, and its molecular weight was estimated to be 119000. The O-acetyl groups in the glucomannan was identified and the content amounted to 22.7%. They were located at positions 6 and 2, 6 of most of the D-mannose units. Methylation, periodate oxidation, partial acetolysis, and enzymatic degradation studies showed that the glucomannan is mainly composed of β-1→4 linked aldohexopyranose residues, and that it contains about 42 aldohexose units per non-reducing group on average. D-Mannose units occupy non-reducing terminal positions and branching points linked through position 3.

Plant mucilages. XIX. Isolation and characterization of a mucous polysaccharide, "Lilium-Lo-glucomannan," from the bulbs of Lilium longiflorum.

A mucous polysaccharide, named Lilium-Lo-glucomannan, has been isolated from the bulbs of Lilium longiflorum THUNB. It was homogeneous on glass-fiber paper electrophoresis and in ultracentrifugal analysis. The component sugars of it were D-mannose and D-glucose in the molar ratio of 5 : 2, and its molecular weight was estimated at 263000. Methylation, periodate oxidation, and partial acetolysis studies suggested that the polysaccharide is mainly composed of β-1→4 linked aldohexopyranose residues and it contains about ten aldohexose units per non-reducing terminal group on the average. D-Mannose units occupy non-reducing terminal positions and branch points linked through positions 2 or 3. The O-acetyl groups in the polysaccharide were identified and determined as the content of 3.2%. They were located in positions 6, 2, 6, 3, 6, and 2, 3, 6 of a part of D-mannose units, and 6 and 2, 3, 6 of a part of D-glucose units.

Plant mucilages. XXI. Isolation and characterization of a mucous polysaccharide, "Lilium-Ma-glucomannan," from the bulbs of Lilium maculatum.

A mucous polysaccharide, named Lilium-Ma-glucomannan, has been isolated from the bulbs of Lilium maculatum THUNB. It was homogeneous on glass-fiber paper electrophoresis and by ultracentrifugal analysis. The component sugars of the glucomannan were D-mannose and D-glucose in the molar ratio of 7 : 4, and its molecular weight was measured at 184000. Methylation, periodate oxidation, and partial acetolysis studies suggested that the polysaccharide is mainly composed of β-1→4 linked aldohexopyranose residues and it contains about seven aldohexose units per one end group on the average. D-Mannose units occupy non-reducing terminal positions and branching points linked through positions 2 or 3. The O-acetyl groups in the glucomannan were identified and determined as the content of 4.7%. They were located in positions 2, 3, 6, 3, 6, and 2, 3, 6 of a part of D-mannose units, and 6 and 2, 3, 6 of a part of D-glucose units.