Spirostanol saponins from Paris polyphylla,structures of polyphyllin C,D, E and F

The structures of four new saponins, polyphyllin C, D, E and F, isolated from the tubers of Paris polyphylla have been elucidated as diosgenin-3-O-α-l-rhamnopyranosyl(1→3)-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→3)- [α-l-arabinofuranosyl(1→4)]-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→2)-α-l-rhamnopyranosyl (1→4)[α-l-rhamnopyranosyl(1→3)]-β-d-glucopyranoside and diosgenin-3-O-α-l-rhamnopyranosyl(1→4)[α-l- rhamnopyranosyl(1→3)][β-d-glucopyranosyl(1→2)]-α-l-rhamnopyranoside, respectively, on the basis of chemical and spectral data.     

Furostanol saponins from Paris polyphylla: Structures of polyphyllin G and H

The structure of two new saponins, polyphyllins G and H, isolated from the tubers of Paris polyphylla have been elucidated as 3-O-{α-l-rhamnopyranosyl (1→3) [α-l-arabinofuranosyl (1→4)]-β-d-glucopyranosyl}-26-O-[β-d-glucopyranosyl] (25R)-22α-hydroxy-furost-5-en-3β, 26-diol and its 22-methoxy derivative respectively.     

Comparative studies of asparagine-linked oligosaccharide structures of rat liver microsomal and lysosomal beta-glucuronidases

The sugar chains of microsomal and lysosomal β-glucuronidases of rat liver were studied by endo-β-N-acetylglucosaminidase H digestion and by hydrazinolysis. Only a part of the oligosaccharides released from microsomal β-glucuronidase was an acidic component. The acidic component was not hydrolyzed by sialidase and by calf intestinal and Escherichia coli alkaline phosphatases, but was converted to a neutral component by phosphatase digestion after mild acid treatment indicating the presence of a phosphodiester group. The neutral oligosaccharide portion of microsomal enzyme was a mixture of five high mannose-type sugar chains: (Manα1 → 2)_0~4 [Manα1 → 6(Manα1 → 3)Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc]. In contrast, lysosomal enzyme contains only Manα1 → 6 (Manα1 → 3) Manα1 → 6(Manα1 → 3) Manβ1 → 4GlcNAcβ1 → 4GlcNAc. The result indicates that removal of α1 → 2-linked mannosyl residues from (Manα1 → 2)₄[Manα1 → 6(Manα1 → 3)Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc → Asn] starts already in the endoplasmic reticulum of rat liver.     

Oligosaccharides on cathepsin D from porcine spleen

Cathepsin D from porcine spleen contained mannose (3.3%), glucosamine (1.4%), and mannose 6-phosphate (0.08%). Essentially all of the oligosaccharides of cathepsin D could be released by endo-β-N-acetylglucosaminidase H, pointing to oligomajmoside types of structures. Three neutral oligosaccharide fractions, containing 5, 6, and 7 mannose residues, respectively, were isolated by gel permeation chromatography on Bio-Gel P-2. Studies using exoglycosidase digestions and 500-MHz ¹H NMR spectroscopy revealed that their structures are [Manα1 → 2]_{0 or 1}Manα1 → 6[Manα1 → 3]Manα1 → 6[(Manα1 → 2)_{0 or 1}Manα1 → 3]Manβ1 → 4GlcNAcβ1 → 4 GlcNAc. These structures are identical to what have recently been proposed by Takahashi et al. for the major oligosaccharide units of cathepsin D from the same source (T. Takahashi P.G. Schimidt, and J. Tang (1983)J. Biol. Chem.258, 2819–2930), except for the occurrence of two isomeric oligosaccharides containing six mannoses. Only a part (3.4%) of the oligosaccharides were acidic, containing phosphates in monoester linkage. The phosphorylated oligosaccharides also consisted of oligomannoside-type chains which were analogous to, but more heterogeneous in size than the neutral oligosaccharides. Cathepsin D was bound to a mannose- and N-acetylglucosamine-specific lectin (mannan-binding protein) isolated from rabbit liver with the K_i value of 5.4 × 10^?6m.     

Synthesis of two purple-membrane glycolipids and the glycolipid sulfate O-(β-d-glucopyranosyl 3-sulfate)-(1→6)-O-α-d-mannopyranosyl-(1→2)-O-α-d-glucopyranosyl-(1→1)-2, 3-di-O-phytanyl-sn-glycerol

The two purple-membrane glycolipids O-β-d-glucopyranosyl- and O-β-d-galactopyranosyl-(1→6)-O-α-d-mannopyranosyl-(1→2)-O-α-d-glucopyranosyl-(1→1)-2, 3-di-O-phytanyl-sn-glycerol were prepared by coupling O-(2,3,4-tri-O-acetyl-α-d-mannopyranosyl)-(1→2)-O-(3,4,6-tri-O-acetyl-α-d-glucopyranosyl)-(1→1)-2, 3-di-O-phytanyl-sn-glycerol (9) with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide or 2,3,4,6-tetra-O-acetyl-α-d-mannopyranosyl bromide, respectively, followed by deacetylation. The glycolipid sulfate O-(β-d-glucopyranosyl 3-sulfate)-(1→6)-O-α-d-mannopyranosyl-(1→2)-O-α-d-glucopyranosyl-(1→1)-2,3-di-O-phytanyl-sn-glycerol was prepared by coupling of 9 with 2,4,6-tri-O-acetyl-3-O-trichloroethyloxycarbonyl-α-d-glucopyranosyl bromide in the presence of Hg(CN)₂/HgBr₂ followed by selective removal of the 3?-trichloroethyloxycarbonyl group, sulfation of HO-3?, and deacetylation. The suitably protected key-intermediate 9 could be prepared by two distinct approaches.     

Purification and substrate specificity of an endo-dextranase of Streptococcus mutans K1-R

An extracellular endo-dextranase has been isolated from Streptococcus mutans K1-R. Incubation of cell-free culture fluid with sucrose permitted the removal of a large proportion of the extracellular d-glucosyltransferases by irreversible adsorption onto the insoluble glucans that these enzymes synthesize from sucrose. The remaining d-glucosyltransferases were separated from dextranase by precipitation with ammonium sulphate, chromatography on hydroxylapatite and DEAE-cellulose, followed by filtration on Ultrogel. The major products of action of the purified dextranase on (1→6)-α-d-glucans were isomaltotriose (IM₃), isomaltotetraose (IM₄), and isomaltopentaose (IM₅). Further hydrolysis of IM₄ and IM₅ occurred after prolonged incubation with excess of enzyme, to give d-glucose, IM₂, and IM₃. The relative rate of hydrolysis of isomaltose saccharides fell sharply with decreasing chainlength from IM₁₂ to IM₅. The hydrolysis of dextrans containing 96% or more of (1→6)-α-d-glucosidic linkages, expressed as apparent conversion into IM₃, was virtually complete, and substrates such as Streptococcus sanguis glucan, containing sequences of (1→6)-α-d-glucosidic linkages, were also effectively hydrolyzed. Dextranase activity towards the soluble glucan of Streptococcus mutans was limited, and there was no action on the insoluble glucan synthesized by S. mutans sucrose 3-d-glucosyltransferase.     

An expeditious synthesis of blood-group antigens,ABO histo-blood group type II antigens and xenoantigen oligosaccharides with amino type spacer−arms

Blood group oligosaccharides are one of the most clinically important antigen families and they may also act as secondary ligands for bacterial toxins from Escherichia coli and Vibrio cholerae. Herein we report the synthesis of spacered (sp = CH₂CH₂CH₂NH₂) glycosides of A antigen {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-}, B antigen{α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-}, LewisX{α-D-Gal-(l→4)-[α-L-Fuc-(l→3)]-β-D-GlcNAc-}, A type-II {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-(1→4)-β-D-GlcNAc-}, B type-II {α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-(1→4)-β-D-GlcNAc-}, H type-II{α-L-Fuc-(l→2)-β-D-Gal-(1→4)-β-D-GlcNAc-}, xenoantigen {α-D-Gal-(l→3)-β-D-Gal-(1→4)-[α-L-Fuc-(l→2)]-β-D-GlcNAc-} and Linear B Type II {α-D-Gal-(l→3)-β-D-Gal-(1→4)-β-D-GlcNAc-} useful for a range of biochemical investigations. This linker was chosen so as to facilitate the future conjugation of the antigens to proteins or other molecules. We also measured the affinities of some synthesized oligosaccharides against El Tor CTB strain from V. cholera.     

Structural elucidation of new phenolic glycolipids from Mycobaclerium tuberculosis

From one clinical isolate of Mycobacterium tuberculosis, two new phenolic glycolipids(PGLs) were obtained as its major PGLs. These were dimycocerosyl esters of 2,4-di-O-methyl-fucopyranosyl-(α1 → 3)-rhamnopyranosyl-(α1 → 3)-2-0-methyl-rhamno-pyranosyl-(α1 →)-phenolph A and -phenolphthiotriol A, which were produced by this strain at a ratio of about 5:1. Another clinical isolate of this species was found to produce PGL-tb1 and its analogue, 2,3,4-tri-O-methyl-fucopyranosyl-(α1 → 3)-rhamnopyranosyl-(α1 → 3)-2-O-methyl-rhamnopyranosyl-(α1 →)-phenolphthiotriol A at a ratio of about 1:3. The fact that different strains of M. tuberculosis produce chemically different PGLs as their major PGLs may be related to the diversity of virulence of the clinical isolates of M. tuberculosis.     

Structural studies of the carbohydrate moiety of human antithrombin III

Human antithrombin III contains four asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively released as radioactive oligosaccharides from the polypeptide portion by hydrazinolysis followed by N-acetylation and NaB³H₄ reduction. All of the oligosaccharides, thus obtained, contain N-acetylneuraminic acid. A same neutral nonaitol was released from all acidic oligosaccharides by sialidase treatment. By combination of the sequential exoglycosidase digestion and methylation analysis, their structures were elucidated as NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6-(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manαl → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, and NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc.     

Synthese der “repeating unit” der O-spezifischen kette des lipopolysaccharides aus Aeromonas salmonicida

8-Methoxycarbonyloctyl 2-azido-4,6-O-benzylidene-2-deoxy-β-d-mannopyranoside reacted with 2,3,4-tri-O-acetyl-α-l-rhamnopyranosyl bromide to give a disaccharide from the which the glycosyl-acceptor 8-methoxycarbonyloctyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(2,4,-di-O-acetyl-α-l-rhamnopyranosyl)-β-d-manno pyranoside (19) was obtained. This glycosyl-acceptor with 2,3,4,6-tetra-O-benzyl-α-d-glucopyranosyl chloride to give trisaccharide derivative 22 and with 2,3,6-tri-O-(α-²H₂)benzyl-4-O-(2,3,4,6-tetra-O-(α-²H₂)benzyl-α-d-glucopyranosyl)-α-d-glucopyranosyl chloride to give tetrasaccharide derivative 29. Deblocking of 22 yielded 8-methoxycarbonyloctyl O-(α-d-glucopyranosyl)-(1→3)-O-α-l-rhamnopyranosyl-(1→3)-2-acetamido-2-deoxy-β-d-mannopyranoside and deblocking of 29 8-methoxycarbonyloctyle O-α-d-glucopyranosyl-(1→4)-O-α-d-glucopyranosyl-(1→3)-O-α-l-rhamnopyranosyl- (1→3)-2-acetamido-2-deoxy-β-d-mannopyranoside. Both oligosaccharides represent the “repeating unit” of the O-specific chain of the lipopolysaccharide from Aeromonas salmonicida.     

Structure of the water-insoluble α-d-glucan of streptococcus salivarius HHT

Water-insoluble, non-adherent α-d-glucans have been obtained from Streptococcus salivarius HHT under two sets of conditions: from a growing culture, or synthesized enzymically by using a glucosyltransferase. In the former case, the glucan ([α]_d + 197°) was shown by methylation analysis to have a slightly branched structure containing a relatively high proportion (80 %) of (1→3)-α-d-glucosidic linkages, together with small proportions of (1→6)- and (1→4)-α-d-glucosidic linkages. The enzymically synthesized glucan had a much less-branched structure, containing 88 % of (1→3)-α-d-glucosidic linkages. Both glucans, on Smith degradation (sequential periodate oxidation, borohydride reduction, and mild acid hydrolysis), gave linear, (1→3)-α-d-glucosidic polysaccharides (yields, 82-90%) that constitute the backbone chains. The presence of small proportions of glycerol, erythritol, 1-O-α-d-glucosyl-d-glycerol, and also 2-O-α-d-glucosyl-d-erythritol in the products of Smith degradation suggests that the short side-chains are attached to the backbone chain by (1→4)-, (1→6)-, and (1→3)-α-d-glucosidic linkages     

Subcomponents C1q of the first component of guinea pig and mouse complement: Comparative study of their asparagine-linked sugar chains

Guinea pig and mouse C1q, subcomponents of the first component of complement, contained six asparagine-linked sugar chains on the C-terminal non-collagenous globular regions of each molecule. After N-acetylation and successive NaB³H₄-reduction of asparagine-linked sugar chains liberated by hydrazinolysis, their structure was analysed by sequential exoglycosidase digestion in combination with sugar composition analyses. The sugar chains of C1q molecules of both animals were very similar and composed of the biantennary complex type sugar chains with the following outer chains in various combinations: (± NeuNAcα → )Galß1 → GlcNAcß1 → and Galß1 → Galß1 → GlcNAcß1 →. These chain moieties were found to be linked to a common core structure of Manα1 → (Manα1 → )Manß1 → GlcNAcß1 → (Fucα1 → )GlcNAc.     

Oleanane-type glycosides from Weigela x Styriaca and two cultivars of W. florida: “Minor black” and “Brigela”

Sixteen oleanane-type glycosides were extracted from three Weigela hybrids and cultivars: W. x Styriaca, W. florida “Minor black” and W. florida “Brigela”, and four of them were previously undescribed ones: 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyloleanolic acid, 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, and 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid. Their full structural elucidation required extensive 1D and 2D NMR experiments, as well as mass spectrometry analysis. Six compounds among the known ones were in sufficient amount to be tested for their antifungal activity against Candida albicans, and their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.     

Melongosides n,o and p: steroidal saponins from seeds of solanum melongena

Three new saponins, melongosides N, O and P, have been isolated from the methanolic extract of seeds of Solanum melongena and their structures elucidated. Melongoside N is 3-O-[β-D-glucopyranosy l-(1 → 2)-β-D-glucopyranosyl]-26-O-(β-D-glucopyranosyl)-(25R)-5α-furostan-3β,22 α,26-triol, whereas melongoside O is 3-O-[β-D-glucopyranosyl-(1 → 2)β-D-glucopyranosyl]- 26-O-(β-D-glucopyranosyl)-(25R)-furost-5-en-3β,22α,26-triol and melongoside P is 3-O- [β-D-glucopyranosyl-(1 → 2)]-[α-L-rhamnopyranosyl-(1 → 3)]-β-D-glucopyranosyl)-26-O- (β-D-glucopyranosyl)-(25 R)-5α-furostan-3β,22α,26-triol.     

OLIGOSACCHARIDE STORAGE IN BRAINS FROM PATIENTS WITH FUCOSIDOSIS,GM1-GANGLIOSIDOSIS AND GM2-GANGLIOSIDOSIS (SANDHOFF'S DISEASE)1

Abstract— Analysis of whole autopsy brain from a patient with fucosidosis (α-fucosidase deficiency) revealed minor storage of H-antigen glycolipid [Fuc (α, 1→2) Gal-GlcNAc-Gal-Glc-Ceramide] and a slightly abnormal ganglioside composition in the form of a two-fold elevation of G_M1 and the presence of a fucose-containing glycolipid (a minor component) which co-migrated with G_D1a. The major storage materials in fucosidosis brain were an oligosaccharide (Fuc-Gal-GlcNAc-Man[Fuc-Gal-GlcNAc-Man]-ManGlcNAc) and a disaccharide [Fuc(α, 1→6)-GlcNAc] in the approximate ratio of 5:1. Lesser amounts of a related oligosaccharide (Gal-GlcNAc-Man[Gal-GlcNAc-Man]-Man-GlcNAc) were isolated from the brain of patients with G_M1-gangliosidosis (Types I and II) where the major storage material is known to be G_M1-ganglioside (Gal (β, 1→3)GalNAc(β, 1→4) [NeuNAcf(α, 2→3) Gal(β, 1→4)Glc-Ceramide). Similarly, a related oligosaccharide (GlcNAc-Man [GlcNAc-Man]-Man-GlcNAc) was isolated from the brain of a patient with a total deficiency of N-acetyl-β-d -hexosaminidase (Sandhoff variant of G_M2-gangliosidosis) where the major storage products are known to be G_M2-ganglioside (GalNAc (β 1→4) [NeuNAc (α, 2→3)Gal(β, 1→4)Glc-Ceramine) and its asialo derivative. These studies indicate that glycoproteins containing at least 2 mol of l -fucose per oligosaccharide unit are normally catabolized in human brain. Further, it appears that such glycoproteins are initially catabolized by an endo-N-acetylglucosaminidase to release an oligosaccharide which is then degraded by the sequential action of exo-glycosidases.     

Flavonol glycosides and lignans from the leaves of Opilia amentacea

Two previously undescribed flavonol tetraglycosides, isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (1) and isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside (2), along with nine known compounds including seven flavonoids and two lignans, were isolated from the leaves of Opilia amentacea Roxb (Opiliaceae). Their structures were established on the basis of spectroscopic analysis. The DPPH radical scavenging activity of compounds 1–11 was evaluated. In addition, all compounds were evaluated for their tyrosinase inhibitions by using in vitro mushroom tyrosinase assay. Only 5,5-dimethoxylariciresinol-4-O-β-d-glucopyranoside (10) and eleutheroside E1 (11) exhibited significant tyrosinase inhibition (IC₅₀ 42.1 and 28 μM, respectively) and DPPH radical scavenging activity (IC₅₀ 85.1 and 42.1 μM, respectively) compared with the positive controls.     

Steroidal saponins of Asparagus curillus

Three spirostanol and two furostanol glycosides were isolated from a methanol extract of the roots of Asparagus curillus and characterized as 3-O-[α-l-arabinopyranosyl (1→4)- β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{α-l-rhamnopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-(25S)-5β-spirostan- 3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β- d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- 22α-methoxy-(25S)-5β-furostan-3β, 26-diol and 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- (25S)-5β-furostan-3β, 22α, 26-triol respectively.     

Structural studies on some saponins from Lecaniodiscus cupanioides

Four triterpenoid saponins isolated from the stem bark of Lecaniodiscus cupanioides and denoted S-2,S-3,S-4 and S-5, were identified as follows. S-2:3-O-[α-l-arabinopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]-hederagenin; S-3:3-O-[α-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabino-pyranosyl ]-hederagenin; S-4:3-O- [α-l-arabinopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→ 2)-α-l-arabinopyranosyl]-hederagenin; S-5:3-O- [α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl ]-hederagenin. Of these, S-2 and S-4 are new substances.     

Trans-α-xylosidase,a widespread enzyme activity in plants,introduces (1→4)-α-d-xylobiose side-chains into xyloglucan structures

Angiosperms possess a retaining trans-α-xylosidase activity that catalyses the inter-molecular transfer of xylose residues between xyloglucan structures. To identify the linkage of the newly transferred α-xylose residue, we used [Xyl-³H]XXXG (xyloglucan heptasaccharide) as donor substrate and reductively-aminated xyloglucan oligosaccharides (XGO–NH₂) as acceptor. Asparagus officinalis enzyme extracts generated cationic radioactive products ([³H]Xyl·XGO–NH₂) that were Driselase-digestible to a neutral trisaccharide containing an α-[³H]xylose residue. After borohydride reduction, the trimer exhibited high molybdate-affinity, indicating xylobiosyl-(1→6)-glucitol rather than a di-xylosylated glucitol. Thus the trans-α-xylosidase had grafted an additional α-[³H]xylose residue onto the xylose of an isoprimeverose unit. The trisaccharide was rapidly acetolysed to an α-[³H]xylobiose, confirming the presence of an acetolysis-labile (1→6)-bond. The α-[³H]xylobiitol formed by reduction of this α-[³H]xylobiose had low molybdate-affinity, indicating a (1→2) or (1→4) linkage. In NaOH, the α-[³H]xylobiose underwent alkaline peeling at the moderate rate characteristic of a (1→4)-disaccharide. Finally, we synthesised eight non-radioactive xylobioses [α and β; (1↔1), (1→2), (1→3) and (1→4)] and found that the [³H]xylobiose co-chromatographed only with (1→4)-α-xylobiose. We conclude that Asparagus trans-α-xylosidase activity generates a novel xyloglucan building block, α-d-Xylp-(1→4)-α-d-Xylp-(1→6)-d-Glc (abbreviation: ‘V’). Modifying xyloglucan structures in this way may alter oligosaccharin activities, or change their suitability as acceptor substrates for xyloglucan endotransglucosylase (XET) activity.     

Structure of a β-galactan isolated from the nuclei of Physarum polycephalum

A sulfated and phosphorylated β-D-galactan ([α]_D + 8°) was isolated from the nuclei of the acellular slime mould Physarum polycephalum. The polysaccharide was isolated from cesium chloride gradients during the preparation of ribosomal DNA and purified. The purified galactan contained 89% galactose, 2.5% phosphate and 9.6% sulfate groups and had an average degree of polymerisation of 560. Periodate degradation and permethylation studies indicated the presence of mainly (1 → 4)-, but also of (1 → 3)-, and (1 → 6)-linked galactose units with one branch every 13 units. These results suggested that the intranuclear galactan, apart from its higher sulfate content, is similar to the extra-cellular polysaccharide produced by P. polycephalum.