D-galactofuranosyl Residues Research Articles

Structure of the high molecular weight exopolysaccharide produced by Bifidobacterium animalis subsp. lactis IPLA-R1 and sequence analysis of its putative eps cluster

The bile adapted strain Bifidobacterium animalis subsp. lactis IPLA-R1 secretes a high molecular weight exopolysaccharide (HMW-EPS) when grown on the surface of agar-MRSC. This EPS is composed of l-rhamnopyranosyl, d-glucopyranosyl, d-galactopyranosyl and d-galactofuranosyl residues in the ratio of 3:1:1:1. Linkage analysis and 1D and 2D NMR spectroscopy were used to show that the EPS has a hexasaccharide repeating unit with the following structure: [Display omitted] Treatment of the EPS with mild acid cleanly removed the terminal d-galactofuranosyl residue. The eps cluster sequenced for strain IPLA-R1 showed high genetic homology with putative eps clusters annotated in the genomes of strains from the same species. It is of note that several genes coding for rhamnose-precursors are present in the eps cluster, which could be correlated with the high percentage of rhamnose detected in its EPS repeated unit.

ChemInform Abstract: The First Chemical Synthesis of UDP-α-D-Galactofuranose.

Uridine 5′-diphosphate α-D-galactofuranose, which is likely to be a biochemical donor of D-galactofuranosyl residues in Nature, is synthesized from α-D-galactofuranosyl phosphate and uridine 5′-monophosphate.

Structural Characterization and DPPH Radical Scavenging Activity of an Arabinoglucogalactan from Panax notoginseng Root

The structure of an antiradical arabinoglucogalactan ( 1) from Panax notoginseng roots was determined. This polymeric carbohydrate was obtained through successive phosphate buffer (pH 7.0) extraction after cold-water pretreatment and purification by ion-exchange and gel-filtration chromatography. Monosaccharide analysis, permethylation analysis, NaIO 4 and CrO 3 oxidations, Smith degradation, graded acid hydrolysis, and IR and NMR experiments indicated that 1 possesses a backbone of (1-->3)-linked beta- d-galactofuranosyl residues, with branches of alpha- l-Ara f-(1-->4)-beta- d-Glc p-(1--> residues at O-6. Additionally, 1 exhibited high scavenging activity against DPPH free radicals with a 50% scavenging concentration (SC50) of 11.72 +/- 0.91 microg/mL, suggesting that this arabinoglucogalactan is a potential antiradical.

Human Intelectin Is a Novel Soluble Lectin That Recognizes Galactofuranose in Carbohydrate Chains of Bacterial Cell Wall

Galactofuranosyl residues are present in various microorganisms but not in mammals. In this study, we identified a human lectin binding to galactofuranosyl residues and named this protein human intelectin (hIntL). The mature hIntL was a secretory glycoprotein consisting of 295 amino acids and N-linked oligosaccharides, and its basic structural unit was a 120-kDa homotrimer in which 40-kDa polypeptides were bridged by disulfide bonds. The hIntL gene was split into 8 exons on chromosome 1q21.3, and hIntL mRNA was expressed in the heart, small intestine, colon, and thymus. hIntL showed high levels of homology with mouse intelectin, Xenopus laevis cortical granule lectin/oocyte lectin, lamprey serum lectin, and ascidian galactose-specific lectin. These homologues commonly contained no carbohydrate recognition domain, which is a characteristic of C-type lectins, although some of them have been reported as Ca(2+)-dependent lectins. Recombinant hIntL revealed affinities to d-pentoses and a d-galactofuranosyl residue in the presence of Ca(2+), and recognized the bacterial arabinogalactan of Nocardia containing d-galactofuranosyl residues. These results suggested that hIntL is a new type lectin recognizing galactofuranose, and that hIntL plays a role in the recognition of bacteria-specific components in the host.

The first chemical synthesis of UDP-α-D-galactofuranose

Uridine 5′-diphosphate α-D-galactofuranose, which is likely to be a biochemical donor of D-galactofuranosyl residues in Nature, is synthesized from α-D-galactofuranosyl phosphate and uridine 5′-monophosphate.

Novel structures of N-linked high-mannose type oligosaccharides containing α- d-galactofuranosyl linkages in Aspergillus niger α- d-glucosidase

Seven oligosaccharides were isolated from α- d-glucosidase (EC 3.2.1.20) from Aspergillus niger, and the structures of these oligosaccharides were studied by 1H NMR spectroscopy. After treatment of the α- d-glucosidase with N-glycosidase F, seven major oligosaccharide peaks were detected by Dionex anion-exchange HPLC. The structures corresponding to the three peaks OS-1, OS-2, and OS-4 were determined to be Man 8GlcNAc 2, and GlcMan 9GlcNAc 2, respectively, from 1H NMR spectra of the isolated fractions. Each of the four oligosaccharides OS-5, OS-6, OS-7-1, and OS-7-2 contained an α- d-galactofuranosyl residues (Gal f) linked to Man (A) via an α-(1 → 2)-linkage. OS-7 was found to consist of two oligosaccharides. The structures of these four oligosaccharides were determined to be Gal fMan 5GlcNAc 2, Gal fMan 6GlcNAc 2, Gal fMan 7-GlcNAc 2, and Gal fMan 8GlcNAc 2 by 1H NMR spectroscopy and compositional analysis. The Gal f structure of Gal fMan 5GlcNAc 2 was found to be identical to that of an oligosaccharide previously isolated from the α- d-galactosidase of the same strain 1. The structure of OS-3 remains undetermined.

Isolation, characterization, and antitumor activities of the cell wall polysaccharides from Elsinoe leucospila.

A cell-wall preparation from the cells of Elsinoe leucospila, which produces elsinan extracellularly when grown on sucrose or glucose-potato extract medium, was fractionated systematically. The heteropolysaccharide that was released by treatment with Actinase E digestion, comprised D-mannose, D-galactose, and D-glucose (molar ratio, 1.5:1.0:0.1). Methylation, mild acid hydrolysis, and 13C-NMR studies suggested that the polysaccharide contains a backbone of alpha-(1----6)-linked D-mannose residues having two kinds of side chains, one attached at the O-4 with single or short beta-(1----6)-linked D-galactofuranosyl residues, and the other attached at O-2 with short side chains, most probably, of alpha-(1----3)-linked D-mannopyranosyl residues. A moderately branched D-glucan fraction, obtained from the cold alkali extract, was fractionated to give an antitumor-active purified beta-(1----3)-glucan having branches of single beta-D-glucosyl groups, one out of eight D-glucose residues being substituted at the O-6.

Isolation and analysis by the reductive-cleavage method of linkage positions and ring forms in the Mycobacterium smegmatis cell-wall arabinogalactan

The Mycobacterium smegmatis arabinogalactan polysaccharide has been isolated from the cell wall by saponification and extraction to remove lipids and subsequent solubilization by treatment with lysozyme. Analysis for neutral sugars demonstrated the presence of d-arabinose and d-galactose in a ratio of 3:1, respectively. Reductive cleavage of the fully methylated polysaccharide in the presence of triethylsilane and trimethylsilyl trifluoromethanesulfonate and subsequent acetylation in situ gave six partially methylated 1,4-anhydroalditol acetates as the major products and three partially methylated 1,5-anhydroalditol acetates as minor products. Partially methylated 1,5-anhydroalditol acetates were not formed when reductive cleavage was accomplished with triethylsilane and a mixture of trimethylsilyl methanesulfonate and boron trifluoride etherate as the catalyst, demonstrating that the polysaccharide is exclusively comprised of furanosyl residues. The partially methylated anhydroalditols so produced were identified by comparison to authentic standards. Their identities are consistent with the presence in the M. smegmatis arabinogalactan of an octasaccharide repeating unit comprised of a nonreducing terminal d-arabinofuranosyl group, a 2- O-linked d-arabinofuranosyl residue, three 5- O-linked d-arabinofuranosyl residues, a 3,5-di- O-linked d-arabinofuranosyl residue, a 5- O-linked d-galactofuranosyl residue, and a 6- O-linked d-galactofuranosyl residue.

A Rapid and Reliable Method for the Detection of Molds in Foods: Using the Latex Agglutination Assay

An agglutination test by using latex beads (0.8μm diameter) coated with IgG from the antibodies against extra-cellular polysaccharide of Penicillium digitatum has been developed. As low as 5 to 10 ng/ml of the purified extra-cellular polysaccharide of the same species can be detected by this preparation. Analysis of culture filtrates from 25 different molds showed that the positive reactivity was obtained only with the species of genera Penicillium and Aspergillus. The application of this test was confirmed in testing the samples of spices and nuts. Further, the reliability could be enhanced by including specific blocker in the assay, the synthetic epitopes consisting of four β (1–5)-linked D-galactofuranosyl residues.

Minor, protein-containing galactomannans from the insect-body portion of the fungal preparation Chán huā ( Cordyceps cicadae)

Two minor, water-soluble, protein-containing galactomannans, CI-P ([α] D +15.3°) and CI-A ([α] D +10.6°), isolated from the insect-body portion of the fungal preparation Chán huā ( Cordyceps cicadae) showed single peaks on gel filtration, and one spot on glass-fiber paper electrophoresis. The polymers are composed of d-mannose and d-galactose in the molar ratios of 1:0.85 for CI-P and 1:0.57 for CI-A, together with traces of d-glucose, and small proportions of protein. Although both polysaccharides have a molecular weight of ∼25,000, the affinity of CI-A for Con A was stronger than that of CI-P. From the results of methylation analysis, Smith degradation, stepwise hydrolysis, and 13C-n.m.r. spectroscopy, it was concluded that the polysaccharides are highly branched, with structures composed of (1→6)-linked α- d-mannopyranosyl main chains, having most residues substituted at O-2 with single α- or β- d-galactofuranosyl groups, short chains of (1→2)-linked β- d-galactofuranosyl residues, or chains of (1→2)-linked α- d-mannopyranosyl residues. CI-A has fewer and shorter d-galactofuranosyl side-chains and longer (1→2)-linked α- d-mannopyranosyl side-chains than CI-P.

A minor, protein-containing galactomannan from a sodium carbonate extract of Cordyceps sinensis

A water-soluble, minor, protein-containing galactomannan (CT-4N), [α] D −29.6°, isolated from a 5% sodium carbonate extract of Cordyceps sinensis, showed a homogeneous pattern in gel filtration and one spot in glass-fiber paper-electrophoresis. The molecular weight was estimated by gel filtration to be ∼23,000. It was mainly composed of d-mannose and d-galactose in the molar ratio of 3:5, and contained a small proportion of protein. From the results of methylation analysis, Smith degradation, stepwise hydrolysis, and 13C-n.m.r. spectroscopy, it was concluded that the polysaccharide has a highly branched structure, and is composed of (1→6)- and (1→2)-linked α- d-mannopyranosyl residues in the main chain. Some of the residues are present as branching points of (1→2,6) and (1→4,6) linkages and the branches contain short chains having a large proportion of (1→5)-linked β- d-galactofuranosyl residues and a small proportion of (1→6)-linked α- d-galactopyranosyl resdues, and the (nonreducing) terminal groups consist of a large proportion of β- d-galactofuranosyl and a small proportion of α- d-mannopyranosyl groups.

Comparative studies on the polysaccharides of Cladonia alpestris (reindeer moss), Cladonia confusa, and Cladonia amaurocraea

The chemical structures of polysaccharide components of three species of the lichen genus Cladonia were compared. C. alpestris and C. confusa are similar in overall growth appearance despite different habitats, and each contains traces of water-insoluble nigeran. The residual lichens gave almost pure d-galacto- d-mannans isolated via insoluble Cu complexes formed with Fehling solution. They were not identical but structurally related having (1→6)-linked α- d-mannopyranosyl main-chains substituted in different patterns by β- d-galacto- and α- d-mannopyranosyl groups. Supernatant solutions of the Fehling-solution precipitation contained high proportions of β- d-galactofuranosyl residues. The polysaccharide of C. alpestris contained consecutive (1→2)-linked α- d-mannopyranosyl units substituted in the 6-position by β- d-galactofuranose, whereas that of C. confusa was a d-galactan with both pyranosyl and furanosyl forms. The d-glucan component of C. amaurocraea was isolated together with d-galacto- d-mannan as insoluble Cu complexes. The former was isolated in good yield and proved to be water-insoluble pustulan. The galactomannan had the same overall structure as those of C. alpestris and C. confusa, but showed differences according to the 13C-n.m.r. spectra.

Chemical structure of the d-galacto- d-mannan component from hyphae of Aspergillus niger and other Aspergillus spp

The polysaccharides obtained by alkaline extraction of hyphae of Aspergillus niger 2022 contain d-mannosyl, d-galactosyl, and d--glucosyl units, the proportion of d-galactose decreasing and that of d-mannose increasing with age of culture. The polysaccharide of 5-day cultures contains d-gaIacto- d-mannans with a range of chemical structures, Fehling, precipitation providing polysaccharides of sugar composition which varied from one preparation to the other. This step removed most of the α- d-glucan present and analysis of the d-galacto- d-mannan-rich polysaccharide showed it to contain a core with a main chain of (1→6)-Iinked α- d-mannopyranosyl units substituted in the 2-position with side chains of α- d-mannopyranosyl, O-α- d-mannopyranosyl-(1→2)- O-α- d-mannopyranosyl, and O-α- d-mannopyranosyl-(1→2)- O-α- d-mannopyranosyl-(1→2)- O-α- d-mannopyranosyl units. The methylation and 13C-n.m.r. data indicated side chains of (1→5)-Iinked β- d-galactofuranosyl residues having an average length of ∼4 units and linked to the mannan core at OH-6.Polysaccharides of Aspergillus fumigatus, Aspergillus terreus, Aspergillus flavus, and Aspergillus nidulans, prepared by alkaline extraction of hyphae, and precipitated by Cetavlon in the presence of borate have interrelated chemical structures.

Structural investigation of the capsular polysaccharide of klebsiella serotype K12

Klebsiella K12 capsular polysaccharide has been investigated by the techniques of methylation, Smith degradation—periodate oxidation, uronic acid degradation, and partial hydrolysis, in conjunction with 1H-n.m.r. spectroscopy at 100 and 220 MHz, and 13C-n.m.r. spectroscopy at 20 MHz. The structure has been found to consist of the hexasaccharide repeating-unit shown, having a d-galactofuranosyl residue at the branch point. In this series, a d-galactofuranosyl residue has previously only been found in the polysaccharide from Klebsiella K41. ▪

Structural studies of varianose

The complex carbohydrate varianose, elaborated by Penicillium varians, has been investigated, using methylation analysis, specific degradations, and n.m.r. studies. A main structural element in the glucogalactan portion of the molecule is a tetrasaccharide unit having the structure: ▪ The possibility that this is a true repeating-unit, but that varianose has been enzymically modified during its production, is discussed. The presence of both α and β- D-galactofuranosyl residues in varianose is an unusual feature.

The oxidation of terminal D-galactofuranose residues of a galactan and a glycoprotein by a D-galactose Oxidase preparation from Dactylium dendroides

A galactan, isolated from the unicellular organism Prototheca zopfii, and a glycoprotein from a hyphal cell-wall fraction of the fungus Pithomyces chartarum have been oxidised by a D-galactose oxidase preparation from Dactylium dendroides. The oxidised polymers were subsequently reduced with sodium borotritide. The site of oxidation was identified as C-6 of non-reducing D-galactofuranosyl residues in both polymers.

The specific substance from Pneumococcus type 34 (41). The phosphodiester linkages.

1. The phosphate groups in the type-specific substance S.34 from Pneumococcus type 34 (U.S. type 41) were shown to join the hydroxyl group at position 1 or 5 of ribitol and the hydroxyl group at position 3 of a d-galactofuranosyl residue in the next repeating unit. 2. A partial structure of the type-specific substance was derived. 3. New syntheses of d-galactose 2-phosphate and d-galactose 3-phosphate are described.

The specific substance from Diplococcus pneumoniae: Type 34 (u.s. type 41): the location of the O-acetyl groups

Methyl 6- O-acetyl-β- d-galactofuranoside has been prepared. It strongly inhibits the antigen-antibody precipitation in the homologous Diplococcus pneumoniae Type 34 immune system. The parent methyl β- d-galactofuranoside does not inhibit this precipitation. This result suggests very strongly that the acetyl groups in the capsular polysaccharide of D. pneumoniae Type 34 are located on O-6 of the internal d-galactofuranosyl residues.

The type-specific substance from Pneumococcus type 10A(34). The phosphodiester linkages.

1. The phosphate groups in the type-specific substance S. 10A from Pneumococcus type 10A (34) were shown to join the hydroxyl group at position 1 or 5 of ribitol and the hydroxyl group at position 5 or 6 of a d-galactofuranosyl residue in the next repeating unit. 2. A partial formula of the type-specific substance was derived.