Structure of the D-mannan and D-arabino-D-galactan in Crithidia fasciculata: changes in proportion with age of culture

Cells of the insect flagellate Crithidia fasciculata contained mannan and arabinogalactan components, whose porportion varied with culture age, the former predominating during early stages, and the latter during the later stages of exponential growth and the deceleration phase. The mannan was a beta-D-(1 leads to 2)-linked D-mannopyranan. The arabinogalactan had a complex structure containing, in part, a beta-D-(1 leads to 3)-linked galactopyranose main-chain substituted in the 2 positions by single-unit D-arabinopyranose side-chains and with some unsubstituted units.     

Immunochemical studies on dextran-specific and levan-specific myeloma proteins from nzb mice

Two dextran-specific (PC 3858 and PC 3936) and one levan-specific (PC 3660) NZB myeloma proteins were studied by quantitative precipitin and precipitin-inhibition assays. Both myeloma antidextrans were α-D(1→6) specific and precipitated strongly with a synthetic, linear dextran molecular weight 36,500, and with other dextrans. The two myeloma antidextrans differed with respect to their relative reactivities with dextrans containing various proportions of α-D-(1→6), α-D-(1→4)-like, and α-D-(1→3)-like linkages. In inhibition assays, the two antidextran myeloma proteins behaved differently from each other, from α-D-(1→6)-specific BALB/c myeloma antidextrans, and from the human antidextrans previously studied. Isomalto-oligosaccharides IM3, IM4, and IM5 were all equal in inhibitory power but were only about 60% as potent as IM6 and IM7, which also inhibited equally on a molar basis. Although precipitation with linear dextran suggests that both may have groove-type sites, as previously inferred for QUPC 52, the size of their combining sites is uncertain. It is not clear whether the sites are only as big as three glucose residues with the increased inhibition by six and seven glucose residues being attributable to partial bivalence and to their ability to combine in several ways along the chain, or whether the site is as big as six glucose residues with the increment in binding by the fourth and fifth glucose residues being minimal and the sixth contributing considerable additional binding-energy. The fructan-specific myeloma protein did not react with inulin, but reacted with many levans and with perennial rye-grass levan containing only β-D-(2→6) links. The levan-antilevan reaction was not inhibited by β-D-(2→1)-linked oligosaccharides. The findings suggest that PC 3660 has a specificity for (2→6)-linked chains.     

β-D-(1→4), β-D-(1→3) 'mixed linkage' xylans from red seaweeds of the order Nemaliales and Palmariales

Xylans from five seaweeds belonging to the order Nemaliales (Galaxaura marginata, Galaxaura obtusata, Tricleocarpacylindrica, Tricleocarpa fragilis, and Scinaia halliae) and one of the order Palmariales (Palmaria palmata) collected on the Brazilian coasts were extracted with hot water and purified from acid xylomannans and/or xylogalactans through Cetavlon precipitation of the acid polysaccharides. The β-D-(1→4), β-D-(1→3) 'mixed linkage' structures were determined using methylation analysis and 1D and 2D NMR spectroscopy. The presence of large sequences of β-(1→4)-linked units suggests transient aggregates of ribbon- or helical-ordered structures that would explain the low optical rotations.     

Water-soluble sulfated polysaccharides from the red seaweed Chaetangium fastigiatum. Analysis of the system and the structures of the α-d-(1 → 3)-linked mannans

The water-soluble polysaccharides from Chaetangium fastigiatum were fractionated with cetrimide. The complexed material was subjected to fractional solubilization in solutions of increasing sodium chloride concentration and seven fractions were separated and analyzed. Two of the fractions were subjected to methylation and desulfation-methylation analyses. The results indicate that this seaweed contains a system of sulfated polysaccharides consisting in part of a galactan and an α-d-(1 → 3)-linked mannan, 2- and 6-sulfated, and having single stubs of β-(1 → 2)-linked d-xylose. Composition dispersity of the mannan is produced by variation of the amount and disposition of the sulfate groups and of the content of the xylose side-chains.     

安络小皮伞中水溶性多糖的研究——Ⅰ.甘露聚糖 FP_1 的纯化与结构研究

从安络小皮伞水溶性多糖中分离纯化得一甘露聚糖 FP_1。分子量约为24万。经红外光谱、~+H-NMR 谱和亲和层析指明为β-甘露聚糖。结构分析采用高碘酸氧化、Smith 降解、完全甲基化 GC、GC-MS 与~(13)C-NMR 分析,分子的主链是β-D-(1→6)连接的甘露糖,支链为β-(1→3),β(1→2)甘露糖,分别连接在主链的 O-3和 O-2上。     

Alkali-soluble polysaccharides from Chaetangium fastigiatum: Structure of a xylan

Extraction of the seaweed with dilute alkali after exhaustive treatment with boiling water led to the isolation of a β-D-(1 → 4)-linked xylan and a complex system of polysaccharides containing sulphate.     

Purification,structural characterization and antioxidant property of an extracellular polysaccharide from Aspergillus terreus

The marine fungus Aspergillus terreus produces an extracellular polysaccharide, YSS, when grown in potato dextrose-agar medium. YSS was isolated from the fermented liquids using ethanol precipitation, anion-exchange and size-exclusion chromatography. YSS was mainly composed of mannose and galactose in a molar ratio of 7.68:1.00, its average molecular weight was estimated to be about 18.6 kDa. On the basis of chemical and spectroscopic analyses, including one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopy, structure of YSS may be represented, at an average, as a backbone of mannan with two types of branches. The mannan backbone is mainly composed of (1→2)-linked α-mannopyranose with small amounts of (1→6)-linked α-mannopyranose residues. The branches consist of terminal β-galactofuranose residues, and disaccharide units of (1→6)-linked α-mannopyranose. The branches are linked to C-6 of (1→2)-linked α-mannopyranose residues of backbone. The antioxidant activity of YSS was evaluated with the scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and hydroxyl radicals in vitro, and the results indicated that YSS had good antioxidant activity, especially scavenging ability on DPPH radicals. The investigation demonstrated that YSS is a novel branched galactomannan with antioxidant activity, and differs from previously described extracellular polysaccharides.     

An arabinogalactan from the culture medium of Rubus fruticosus cells in suspension

A water-soluble arabinogalactan, isolated from the extracellular medium of suspension-cultured cells of Rubus fruticosus, contained arabinose, rhamnose, galactose, and also protein (6.5%) and uronic acid (2.5%). Methylation analysis of the arabinogalactan and the arabinose-free product obtained by mild acid hydrolysis showed that the polysaccharide was a typical arabino-3,6-galactan in which rhamnose and glucuronic acid occupied non-reducing terminal positions. Successive Smith-degradations combined with methylation analysis and ¹³C-n.m.r. spectroscopy revealed that the arabinogalactan contained a main chain of (→3)-linked β-d-galactopyranosyl residues with a high degree of branching at positions 6 by (1→6)-linked d-galactopyranosyl side-chains of various lengths, in which several contiguous residues were substituted at positions 3. The polymer is thus an arabinogalactan-protein belonging to the galactans of Type II.     

Cross-Reactive Polysaccharides from Trypanosoma cruzi and Fungi (Especially Dactylium dendroides)1

ABSTRACT. Cross-reactivity between fungal and Trypanosoma cruzi polysaccharides, owing to common residues of β-D-galactofuranose, β-D-galactopyranose, and α-D-mannopyranose, was demonstrated by using a) rabbit immune sera against T. cruzi epimastigotes and b) sera from patients with Chagas’disease. Several chagasic (Ch) sera precipitated partly purified galactomannans from Aspergillus fumigatus and from T. cruzi epimastigotes and also the galactoglucomannan from Dactylium dendroides. Reaction of one Ch serum with T. cruzi galactomannan (GM) was completely inhibited by synthetic β-D-Galf-(1 → 3)-Me α-D-Manp, and that of another Ch serum with a purified D. dendroides galactoglucomannan (GGM) was partly inhibited by (1 → 6)-linked (81%) or by (1 - 3)-linked (33%) β-D-Galf-Me α-D-Manp. The β-D-Galf-(1 → 3)-α-D-Manp epitope was present in both T. cruzi and D. dendroides polysaccharides. Rabbit anti-T. cruzi antisera precipitated A. fumigatus GM, T. cruzi antigenic extracts containing the lipopeptidophosphoglycan (LPPG), T. cruzi alkali-extracted GM, a synthetic GM, and D. dendroides GGM. Weak reactivities were obtained for a Torulopsis lactis-condensi GM containing β-D-Galp terminal residues and for baker's yeast mannan with α-D-Manp-(1 - 3)-α-D-Manp-(1- → 2)-α-D-Manp-(1 → 2) side chains. An anti-LPPG rabbit serum precipitated D. dendroides GGM—a reaction inhibited (82%) by β-D-Galf-(1 → 3)-Me α-D-Manp and, less efficiently, by a (1 → 5)-linked β-D-Galf-tetrasaccharide. Sera from mice immunized with D. dendroides whole cells reacted with CL-strain trypomastigotes as shown a) by indirect immunofluorescence, b) by a Staphylococcus adherence test, but were not lytic. Mice immunized with D. dendroides were not protected against a challenge with virulent T. cruzi trypomastigotes.     

Some structural features of a new sulphated heteropolysaccharide from Padina pavonia

An acid-extractable, water-soluble, polysaccharide sulphate, isolated from Padina pavonia, comprised variable proportions of glucuronic acid, galactose, glucose, mannose, xylose, and fucose in addition to a protein moiety. Partial acid hydrolysis and autohydrolysis of the free acid polysaccharide yielded several oligosaccharides. Evidence from periodate oxidation studies indicated that the inner polysaccharide portion is composed of (1 → 4)-linked β-D-glucuronic acid, (1 → 4)-linked β-D-mannose and (1 → 4)-linked β-D-glucose residues. The heteropolymeric partially sulphated exterior portion is attached to the inner part and comprises various ratios of (1 → 4)-linked β-D-galactose, β-D-galactose-3-sulphate residues, (1 → 4)-linked β-D-glucose residues, (1 → 2)-linked α-L-fucose 4-sulphate residues and (1 → 3)-linked β-D-xylose residues.     

金铁锁的两个新三萜皂苷

从石竹科植物金铁锁(Psammosilene tunicoides W．C．Wu et C．Y．Wu)根部分离得到4个齐墩果酸型五环三萜皂苷。它们的结构通过波谱和化学方法分别鉴定为：3-O-β-D-galac-topyranosyl-(1→2 )-β-D-6-O-methylgtucuronopymnosyl-quillaic acid (1),3-O-β-D-galactopymnosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-gtucuronopyranosyl-quillaic acid (2),3-O-β-D-galactopyrano-syl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-6-O-methylgtucuronopyranosyl-quillaic acid(3),3-O-β-D-galactopymnosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-6-O-ethylgtucuronopyranosyl-quillaic acid(4)。其中1为木鳖子中发现的次甙,3和4为新化合物。     

Structure of Succinoglucan: Fragmentation by Partial Acid Hydrolysis

Succinoglucan, a succinylated polysaccharide produced by Alcaligenes faecalis var. myxogenes 10C3, was partially hydrolyzed with acid. Fractionation of the neutral oligosaccharides gave cellobiose, gentiobiose, laminaribiose, laminaritriose, 6-O-β-laminaribiosylglucose, 6-O-β-laminaritriosylglucose, and 3-O-β-cellobiosylgalactose, confirming the previous results that the polysaccharide consists of β-(l→3)-linked, (1→4)-linked and (1 →6)-linked d-glucose residues, and β-(1→3)-linked d-galactose residues.

Possible structural features of succinoglucan were discussed on the basis of the above and previous results obtained by Smith degradation.     

Purification and chemical characterization of polysaccharides obtained from Lampteromyces japonicus by concanavalin A-sepharose affinity chromatography

Two classes of neutral polysaccharide which could not be separated from each other by conventional methods were isolated from the fungus, Lampteromyces japonicus, by affinity chromatography using concanavalin A-Sepharose. The polysaccharide retained on the concanavalin A-Sepharose column was eluted with 0.05 M methyl α-d-mannopyranoside and appeared to be α-mannan, while that which passed through the column was virtually all β-glucan.Both polysaccharides were subjected to Smith-type degradation, methylation, acetolysis and glucosidase treatment. The results indicated that the α-mannan contained predominantly α-(1 → 2)-linked side chains branching from an α-(1 → 6)-linked backbone at the (1 → 2,6)-linked mannopyranosyl residues. Galactose was attached to approximately one-quarter of the non-reducing mannose terminals. The β-glucan seemed to contain mainly (1 → 6)-linked side chains branching from a (1 → 3)-linked backbone at the (1 → 3,6)-linked glucopyranosyl residues.     

Constitution of sargassan,a sulphated heteropolysaccharide from sargassum linifolium

The behaviour towards periodate of the brown-algal polysaccharide sargassan before and after partial hydrolysis, alkali treatment, and methanolysis has been studied. Evidence is thereby provided that the sargassan backbone is composed of (1→4)-linked β-D-glucuronic acid and β-D-mannose residues. Heteropolymeric, partially sulphated branches are attached to the backbone, and these branches comprise various proportions of(l→4)-linked, β-D-galactose, β-D-galactose 6-sulphate, and β-D-galactose 3,6-disulphate residues, (1→2)-linked α-L-fucose 4-sulphate residues, and (1→3)-linked β-D-xylose residues.     

Acetolysis of disaccharide derivatives

The acetolysis of aldobi-itols and aldobionic acids containing α- and β-(1→2), χ-and β-(1→4), and β-(1→6) linkages has been studied. Cleavage of the (1→4)- and (1→6)-linked derivatives occurred more slowly than for the parent disaccharides. The reverse situation was found for (1→2)-linked aldobi-itols and methyl esters of aldobionic acids.     

The structure of the O-glycosylically-linked oligosaccharide chains of LPG-I,a glycoprotein present in articular lubricating fraction of bovine synovial fluid

Periodate oxidation of LPG-1 established that N-acetylneuraminic acid residues are linked preponderantly α-(2→3) to D-galactose residues. The resistance of 2-acetamido-2-deoxyD-galactose residues to periodate oxidation suggests that they are linked at either O-3 or O-4 to D-galactose residues. After treatment of LPG-I with alkaline sulfite, ≈80% of 2-acetamido-2-deoxygalactose was recovered as the sulfonic acid derivative. The Gal→GalNAc disaccharide released from sialic-acid-free LPG-I by digestion with endo-2-acetamido-2-deoxy-α-D-galactosidase (which suggests an α-D-GalNAc→-L-Ser or -L-Thr linkage) gave a high color-yield in the Morgan—Elson reaction, indicating that 2-acetamido-2-deoxy-D-galactose residues are linked at C-3 to D-galactose residues. The migration of the released Gal-GalNAc disaccharide was the same as that of a standard sample of O-β-D-galactosyl-(1→3)-2-acetamido-2-deoxy-D-galactose. Treatment of sialic acid-free LPG-I with Streptococcus pneumoniae β-D-galactosidase, which hydrolyzes only galactosides linked β-D-(1→4) gave no free D-galactose, whereas treatment of LPG-I with bovine testes β-D-galactosidase released > 90% of D-galactose. These results provide evidence for β-D-Galp-(1→3)-α-D-GalNAcp-(1→3)-L-Ser or -L-Thr and α-NeuAc-(2→3)-β-D-Galp-(1→3)-α-D- GalNAcp-(1→3)-L-Ser or -L-Thr structures. The sensitivity of the methods used and the recovery of constituents following treatment of LPG-I do not rule out the occurrence of small amounts of other tri- or tetra-saccharide chains.     

The molecular structures of a glucan and a galactan synthesised by Prototheca zopfii

When the unicellular organism Prototheca zopfii was grown on a malt-agar medium, a mixture of polysaccharides was synthesised which could be subsequently extracted from the dried cells with hot water and hot alkali. The major polysaccharide was a galactan which had a branched structure with main chains of (1→6)-linked D-galactopyranose residues, and ≈ 10% of side chains containing terminal D-galacto-furanose residues. A glycogen-type polysaccharide and a (1→4)-linked mannan were also produced.     

Structure of Hemicellulose Isolated from Rice Endosperm Cell Wall : Mode of Linkages and Sequences in Xyloglucan, β-Glucan and Arabinoxylan

A hemicellulosic polysaccharide, which was homogeneous on sedimentation analysis and also on electrophoresis, was isolated from the rice endosperm cell walls by the combination of alkaline extraction, ion exchange chromatography and iodine complex formation. It is composed of arabinose, xylose and glucose (molar ratio, 1.0: 2.0: 5.7) together with a small amount of galactose and rhamnose. Methylation analysis, Smith degradation and fragmentation with cellulase showed that this polysaccharide is composed of three distinct polysaccharide moieties i.e., xyloglucan, β-glucan and arabinoxylan. The xyloglucan consists of β-(1→4)-linked glucan back bone and short side chains of single xylose units or galactosylxylose both attached to C-6 of the glucose residues. The β-glucan contains both (1 →3)-and (1→4)-linkages similarly to the other cereal β-glucans, but differ from them in containing the blocks of (1→3)-linked glucose residues in the chain. The arabinoxylan has a highly branched structure, in which 78% of (1→4)-linked xylose residues have short side chains of arabinose at C-3 position.

On the basis of these findings, the interconnection of these polysaccharide moieties is discussed.     

Mannan structural complexity is decreased when Candida albicans is cultivated in blood or serum at physiological temperature

The Candida albicans cell wall provides an architecture that allows for the organism to survive environmental stress as well as interaction with host tissues. Previous work has focused on growing C. albicans on media such as Sabouraud or YPD at 30 °C. Because C. albicans normally colonizes a host, we hypothesized that cultivation on blood or serum at 37 °C would result in structural changes in cell wall mannan. C. albicans SC5314 was inoculated onto YPD, 5% blood, or 5% serum agar media three successive times at 30 °C and 37 °C, then cultivated overnight at 30 °C in YPD. The mannan was extracted and characterized using 1D and 2D ¹H NMR techniques. At 30 °C cells grown in blood and serum contain less acid-stable terminal β-(1→2)-linked d-mannose and α-(1→2)-linked d-mannose-containing side chains, while the acid-labile side chains of mannan grown in blood and serum contain fewer β-Man-(1→2)-α-Man-(1→ side chains. The decrement in acid-stable mannan side chains is greater at 37 °C than at 30 °C. Cells grown on blood at 37 °C show fewer →6)-α-Man-(1→ structural motifs in the acid-stable polymer backbone. The data indicate that C. albicans, grown on media containing host-derived components, produces less complex mannan. This is accentuated when the cells are cultured at 37 °C. This study demonstrates that the C. albicans cell wall is a dynamic and adaptive organelle, which alters its structural phenotype in response to growth in host-derived media at physiological temperature.     

Determination of the structure of dextran by 13C-nuclear magnetic resonance spectroscopy

The ¹³C-n.m.r. spectra have been recorded for a series of dextrans whose structures, in terms of degree and type of branching, had previously been determined by methylation analysis. The spectra established that all observable linkages in these dextrans are α-linked. Correlation of the spectra with methylation data indicated that the 75–85-p.p.m. spectral region is diagnostic for establishing the presence of α-D-(1→2)-, α-D-(1→3)-, or α-D-(1→4)-linkages. Each chemical shift has been found to be temperature-dependent (Δδ/ΔT) when referenced to either the deuterium lock or an external standard (tetramethylsilane). All carbohydrate Δδ/ΔT values are positive, and range from 0.01 to 0.03 p.p.m./°C. These values are considerably larger than analogous Δδ/ΔT values previously observed for smaller molecules. Larger than average Δδ/ΔT values are associated with the non-anomeric, sugar-linking carbon atoms.