Cyclosophoraose as a catalytic carbohydrate for methanolysis

A novel catalytic methanolysis can be induced by a natural cyclooligosaccharide, a cyclosophoraose (cyclic-(1-->2)-beta-D-glucan, Cys), which is a member of a family of unbranched cyclooligosaccharides produced as intra- or extraoligosaccharides by soil microorganisms of the genus, Rhizobium. Cys catalyzed the methanolysis for 5(4H)-oxazolones and various phospholipids. Cys enhanced the methanolysis reaction about 9200-fold for a benzylidene oxazolone or 250-fold for dipalmitoylphosphatidylcholine comparing with control. In this study, we describe that natural cyclosophoraoses isolated from the Rhizobium species function as catalytic carbohydrates for the methanolysis.     

Triterpenoid saponins from Oreopanax guatemalensis

Seven oleanane-type saponins were isolated from the leaves and stems of Oreopanax guatemalensis, together with ten known saponins of lupane and oleanane types. The new saponins were respectively characterized as 3-O-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha- L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-beta-D-glucopyranosyl 3beta-hydroxy olean-11,13(18)-dien-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta- D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]3beta-hydroxy olean-11,13(18)-dien-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]3beta, 23 dihydroxy olean-18-en-28-oic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-6-O-acetyl glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[beta-D-xylopyranosyl-(1-->2 )-]beta-D-glucopyranosyl]ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1-->2)-]beta-D-glucopyranosyl] ester and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl] hederagenin 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-[alpha-L-arabinofuranosyl-(1-->2)]-beta-D-glucopyranosyl] ester. The structures were determined by spectral analyses. The NMR assignments were made by means of HOHAHA, 1H-1H COSY, HMQC, HMBC spectra and NOE difference studies.     

Further saponins from Meryta lanceolata

Five new oleanane-type saponins along with 11 known ones were isolated from the leaves and stems of Meryta lanceolata. The new saponins were characterised by spectroscopic analysis including FAMS, 1 and 2D NMR experiments and the results of hydrolysis as 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] hederagenin 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl] ester, 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl]ester, 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-6-O-acetyl glucopyranosyl-(1-->6)-beta-d-glucopyranosyl]ester, 3-O-[beta-d-glucopyranosyl-(1-->3)-beta-d-glucopyranosyl-(1-->3)-alpha-l-arabinopyranosyl] oleanolic acid 28-O-[alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl] ester and 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucuronopyranosyl] hederagenin, respectively.     

Triterpenoid saponins and phenylethanoid glycosides from stem of Akebia trifoliata var. australis

A detailed phytochemical study on the 70% aqueous ethanol extract of stems of Akebia trifoliata (Thunb.) Koidz. var. australis (Diels) Rehd led to isolation of five compounds, together with 12 known triterpenoid saponins and three known phenylethanoid glycosides. The structures of the five compounds were elucidated on the basis of analysis of spectroscopic data and physicochemical properties as: 2alpha, 3beta, 23-trihydroxy-30-norolean-12-en-28-oic acid beta-D-glucopyranosyl ester (1), 2alpha, 3beta, 23-trihydroxy-30-norolean-12-en-28-oic acid beta-D-xylopyranosyl-(1-->3)-O-alpha-D-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (2), 2alpha, 3beta, 23-trihydroxyurs-12-en-28-oic acid beta-D-xylopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (3), 3-beta-[(beta-D-glucopyranosyl-(1-->3)-O-alpha-L-arabinopyranosyl)oxy]-23-hydroxy-30-norolean-12-en-28-oic acid alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (4) and 3-beta-[(alpha-L-xylopyranosyl-(1-->2)-O-alpha-L-arabinopyranosyl)oxy]-30-norolean-12-en-28-oic acid alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (5), named mutongsaponin A, B, C, D and E, respectively.     

Newbouldiosides A-C, phenylethanoid glycosides from the stem bark of Newbouldia laevis

From the stem bark of Newbouldia laevis three phenylethanoid glycosides, designated as newbouldioside A-C, were isolated together with a sodium salt of analogue B and the known compounds, verbascoside, 5-hydroxydehydro-iso-alpha-lapachone, 3,8-dihydroxydehydro-iso-alpha-lapachone, apigenin and luteolin. The structures of the phenylethanoid glycosides were elucidated by spectroscopic methods as beta-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-beta-D-glucopyranoside, ss-(3,4-dihydroxyphenyl)ethyl 5-O-syringoyl-beta-D-apiofuranosyloxy-(1-->2)-O-[alpha-L-rhamnopyranosyl-(1-->3)]-6-O-E-feruloyl-beta-D-glucopyranoside, and beta-(3,4-dihydroxyphenyl)ethyl 3-O-E-feruloyl-beta-D-apiofuranosyloxy-(1-->2)-O-alpha-L-rhamnopyranosyl-(1-->2)-6-O-E-sinapoyl-beta-D-glucopyranoside, respectively.     

Saponins and acylated saponins from Dizygotheca kerchoveana

Four new triterpenoid saponins were isolated from the leaves and stem of branches of Dizygotheca kerchoveana along with seven known ones. The new saponins were respectively characterized as 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid, 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-3-O-trans-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester and 3-O-[beta-d-3-O-cis-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester. Their structures were elucidated by 1D and 2D NMR experiments, FAB-MS as well as chemical means.     

Triterpenoid saponins from Schefflera arboricola

Nine triterpenoid saponins were isolated from the leaves and stems of Schefflera arboricola. The saponins were characterised, on the basis of chemical and spectral evidence, as 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid, 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] echinocystic acid, 3-O-[beta-D-apiofuranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-ramnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid and 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester.     

Structure of a major glycolipid from Thermus oshimai NTU-063

The structure of a major glycolipid isolated from the thermophilic bacteria Thermus oshimai NTU-063 was elucidated. The sugar and fatty acid compositions were determined by GC-MS and HPLC analysis on their methanolysis and methylation derivatives, respectively. After removal of both O- and N-acyl groups by alkaline treatment, the glycolipid was converted to a fully acetylated tetraglycosyl glycerol derivative, the structure of which was then determined by NMR spectroscopy (TOCSY, HSQC, HMBC). Thus, the complete structure of the major glycolipid from T. oshimai NTU-063 was established as beta-Glcp-(1-->6)-beta-Glcp-(1-->6)-beta-GlcpNAcyl-(1-->2)-alpha-Glcp-(1-->1)-glycerol diester. The N-acyl groups on the 2-amino-2-deoxy-glucopyranose residue are C15:0 and C17:0 fatty acids, whereas the fatty acids of glycerol diester are more heterogeneous including both straight and branched fatty acids from C15:0 to C18:0.     

Biodiesel-fuel production in a packed-bed reactor using lipase-producing Rhizopus oryzae cells immobilized within biomass support particles

A packed-bed reactor (PBR) system using fungus whole-cell biocatalyst was developed for biodiesel fuel production by plant oil methanolysis. Lipase-producing Rhizopus oryzae cells were immobilized within 6 mm × 6 mm × 3 mm cuboidal polyurethane foam biomass support particles (BSPs) during batch cultivation in a 20-l air-lift bioreactor. Emulsification of the reaction mixture containing soybean oils and water improved the methanolysis reaction rate. Using a high flow rate for the reaction mixture in the PBR caused exfoliation of the immobilized cells from the BSPs, while the inefficient mixing of the reaction mixture at low flow rates allowed the BSPs to be covered with a hydrophilic layer of high methanol concentration, leading to a significant decrease in lipase activity. A high methyl ester content of over 90% was achieved at a flow rate of 25 l/h in the first cycle of repeated batch methanolysis and a high value of around 80% was maintained even after the tenth cycle. Comparison with methanolysis reaction in a shaken bottle suggested that the PBR enhances repeated batch methanolysis by protecting immobilized cells from physical damage and excess amounts of methanol. The process presented here is therefore considered to be promising for industrial biodiesel-fuel production.     

Synthesis of the pentasaccharide related to the repeating unit of the antigen from Shigella dysenteriae type 4 in the form of its methyl ester 2-(trimethylsilyl)ethyl glycoside

Starting from D-mannose, D-glucose and L-fucose, the pentasaccharide derivative methyl 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl-(1-->3)-2-O-acetyl-4,6-O-benzylidene-alpha-D-mannopyranosyl-(1-->3)-2-O-acetyl-6-O-benzyl-4-O-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-alpha-D-mannopyranosyl-(1-->4)-[2-(trimethylsilyl)ethyl 2,3-di-O-benzyl-beta-D-glucopyranosid]uronate was synthesized. This compound with two alpha-mannopyranosyl units was transformed, via Walden inversion and subsequent deprotection, into the alpha-D-glucosamine-type target compound, namely methyl alpha-L-fucopyranosyl-(1-->3)-2-acetamido-2-deoxy-alpha-D-glucopyranosyl-(1-->3)-2-acetamido-2-deoxy-4-O-(alpha-L-fucopyranosyl)-alpha-D-glucopyranosyl-(1-->4)-[2-(trimethylsilyl)ethyl beta-D-glucopyranosid]uronate which is related to the repeating unit of the O-antigen from Shigella dysenteriae type 4.     

Muscodor albus MOW12 an Endophyte of Piper nigrum L. (Piperaceae) Collected from North East India Produces Volatile Antimicrobials

Muscodor albus MOW12, an endophytic fungus isolated from Piper nigrum in Mawlong, Meghalaya, India, resembles some cultural and hyphal characteristics of previous isolates of Muscodor sp. In addition, it possesses about 99 % similarity in its ITS rDNA with other M. albus isolates and thus is nicely centered within the genetic tree to other Muscodor spp. This xylariaceae fungus effectively inhibits and kills certain plant pathogenic fungi by virtue of a mixture of volatile compounds that it produces. The majority of these compounds were identified by gas chromatography/mass spectrometry as small molecular weight esters, alcohols, and acids. The main ester components of this isolate of M. albus in its volatile mixture are acetic acid, ethyl ester; propanoic acid, 2-methyl-, methyl ester and acetic acid, 2-methylpropyl ester. This appears to be the first report of any M. albus strain from India.     

Bidesmosidic saponins from the fruits of Diploclisia glaucescens

Chemical investigation of methanol extract of the fruits of Diploclisia glaucescens (Menispermaceae) furnished two new bidesmosidic saponins 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl]phytolaccagenic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]phytolaccagenic acid 28-O-beta-D-glucopyranosyl ester, together with known 3-O-beta-D-glucopyranosylphytolaccagenic acid 28-O-beta-D-glucopyranosyl ester and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]serjanic acid 28-O-beta-D-glucopyranosyl ester. The last saponin is reported for the first time from the family Menispermaceae.     

Structural characterisation of novel lichen heteroglycans by NMR spectroscopy and methylation analysis

Two galactofuranomannans, Ths-4 and Ths-5, were isolated from the lichen, Thamnolia vermicularis var. subuliformis, using ethanol fractionation and anion-exchange and size-exclusion chromatography. The average molecular weights of Ths-4 and Ths-5 were estimated to be 19 and 200 kDa, respectively. Structural characterisation of Ths-4, Ths-5 and their partially hydrolysed derivatives was performed by methanolysis and methylation analysis. The intact and partially hydrolysed Ths-4 was further analysed using NMR spectroscopy (1D, COSY, NOESY, TOCSY, HSQC and HMBC). According to the data obtained, the heteroglycans Ths-4 and Ths-5 have similar structures, but have large differences in molecular weight. The structure is composed of 3-O-linked and 5-O-linked galactofuranosyl chains linked to a mannan core. The mannan core consists of a main chain of alpha-(1-->6)-linked mannopyranosyl residues, substituted at O-2 with either a single alpha-mannopyranosyl unit or an alpha-Manp-(1-->2)-alpha-Manp-(1-->2)-alpha-Manp group in the ratio of approximately 1:3, respectively. The polysaccharides have idealised repeating blocks as is shown.     

Studies on new intracellular proteases in various organs of rat. 1. Purification and comparison of their properties.

1. Specific proteases which inactivate the apo-proteins of many pyridoxal enzymes were found in skeletal muscle, liver and small intestine of rats. The protease from these three organs were purified and their properties were compared. 2. The purified proteases from liver and skeletal muscle appeared homogeneous on acrylamide gel electrophoresis. Two different proteases were separated from small intestine. A homogeneous, crystalline enzyme was obtained from the muscle layer while enzyme from the mucosa was partially purified. 3. They showed substrate specificity for pyridoxal enzymes. Their pH optima were in an alkaline region. They showed activity with the substrate of chymotrypsin, N-acetyl-L-tyrosine ethyl ester, but not with that of trypsin, p-toluenesulfonyl-L-arginine ethyl ester. They were inhibited by pyridoxal phosphate or pyridoxamine phosphate and seryl residues were involved in their active center. 4. The four enzymes differed in the following characters: (a) molecular weights; (b) patterns of elution from a CM-Sephadex column; (c) rates of inactivation of substrate enzymes; (d) rates of cleavage of N-acetyl-L-tyrosine ethyl ester; (e) reactivities with antiserum against the enzyme from the muscle layer of small intestine; (f) specific activities. 5. The amino acid composition and effect of chemical modifications of the crystalline enzyme from the muscle layer of small intestine were examined to elucidate its active sites and mode of action. Serine and histidine residues were found to be essential for protease activity. A tyrosine residue was also necessary for activity. Modifications of its sulfhydryl group, amino residues and carboxyl group had no effect on its activity.     

Synthesis of neoglycoproteins containing O-methylated trisaccharides related to excretory/secretory antigens of Toxocara larvae

The disaccharides allyl beta-D-galactopyranosyl-(1-->3)-2-acetamido-2-deoxy-beta- and alpha-D-galactopyranoside 10a and 10b and the trisaccharides allyl 2-O-methyl-alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->3)-2-acetamido-2-deoxy-beta- and alpha-D-galactopyranoside 18a and 18b have been prepared using stepwise assembly of the sugar units. The glycosidic linkages were formed employing the trichloroacetimidate procedure for the attachment of the galactopyranosyl residue and N-iodosuccinimide/triflic acid activation of an ethyl 1-thiofucopyranoside donor for fucosylation. Deprotection furnished the allyl glycosides which were converted into cysteamine-spacered ligands, activated with thiophosgene and subsequently linked to bovine serum albumin. The neoglycoproteins serve as immunoreagents to determine epitope specificities of monoclonal antibodies directed against highly immunogenic O-glycans located at the surface of Toxocara larvae.     

Oligosaccharide polyester and triterpenoid saponins from the roots of Polygala japonica

An oligosaccharide polyester, 1-O-(E)-p-coumaroyl-(3-O-benzoyl)-beta-D-fructofuranosyl-(2-->1)-[6-O-(E)-feruloyl-beta-D-glucopyranosyl-(1-->2)]-[6-O-acetyl-beta-D-glucopyranosyl-(1-->3)-(4-O-acetyl)-beta-D-glucopyranosyl-(1-->3)]-4-O-[4-O-alpha-L-rhamnopyranosyl-(E)-p-coumaroyl]-alpha-D-glucopyranoside (polygalajaponicose I), and four triterpenoid saponins, 3beta, 23, 27-trihydroxy-29-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-olean-12-en-28-oic acid (polygalasaponin XLVII), 3-O-beta-D-glucopyranosyl presenegenin 28-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranosyl ester (polygalasaponin XLVIII), 3-O-beta-D-glucopyranosyl presenegenin 28-O-beta-D-galactopyranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester (polygalasaponin XLIX) and 2beta, 27-dihydroxy-3-O-beta-D-glucopyranosyl 11-oxo-olean-12-en-23, 28-dioic acid 28-O-beta-D-galactopyranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranosyl ester (polygalasaponin L), in addition to five known compounds have been isolated from the roots of Polygala japonica.     

Chondroitin O-methyl ester: an unusual substrate for chondroitin AC lyase

Chondroitin O-methyl ester was depolymerized by chondroitin AC lyase (EC 4.2.2.5) from Flavobacterium heparinum. The major product isolated from the depolymerization reaction was found to be methyl alpha-L-threo-hex-4-enopyranosyluronate-(1-->4)-2-acetamido-2-deoxy-alpha,beta-D-galactopyranoside.     

Comparative studies of the polysaccharides from species of the genus Ramalina-lichenized fungi-of three distinct habitats

Several structurally different glucans (alpha- and beta-) and galactomannans were characterized as components of four species of the genus Ramalina, namely R. dendriscoides, R. fraxinea, R. gracilis and R. peruviana. Freeze-thawing treatment of hot aqueous extracts furnished as precipitates (PW) linear alpha-D-glucans of the nigeran type, with regularly distributed (1-->3)- and (1-->4)-linkages in a 1:1 ratio. The supernatants (SW) contained alpha-D-glucans with (1-->3)- and (1-->4)-linkages in a molar ratio of 3:1. The lichen residues were then extracted with 2% aq. KOH, and the resulting extracts submitted to the freeze-thawing treatment, giving rise to precipitates (PK2) of a mixture of alpha-glucan (nigeran) and beta-glucan, which were suspended in aqueous 0.5% NaOH at 50 degrees C, dissolving preferentially the beta-glucan. These were linear with (1-->3)-linkages (laminaran). The mother liquor of the KOH extractions (2% and 10% aq. KOH) was treated with Fehling's solution to give precipitates (galactomannans). The galactomannans are related, having (1-->6)-linked alpha-D-mannopyranosyl main chains, substituted at O-4 and in a small proportion at O-2,4 by beta-D-galactopyranosyl units. Despite the different habitats of these lichenized fungi, all species studied in this investigation have a similar pool of polysaccharides.     

Elucidation of two O-chain structures from the lipopolysaccharide fraction of Agrobacterium tumefaciens F/1

Agrobacterium tumefaciens F/1 produces two different O-chains, both are constituted of rhamnose and glucosamine: the less abundant has a linear disaccharidic repeating unit 3)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1--> and the second one 4)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1-->. The two intact antigenic moieties were studied in mixture by 2D NMR. Additional supporting data were obtained by periodate degradation, the major component was cleaved selectively, leading to a glucosamine glycoside, whereas the minor one was recovered unaffected.     

Carbohydrates from Cynanchum otophyllum

Four new carbohydrates were isolated from the acidic hydrolysis part of the ethyl acetate extract of Cynanchum otophyllum Schneid (Asclepiadaceae). Their structures were determined as methyl 2,6-dideoxy-3-O-methyl-beta-D-arabino-hexopyranosyl-(1-->4)-6-deoxy-3-O-methyl-beta-D-ribo-hexopyranosyl-(1-->4)-6-deoxy-3-O-methyl-alpha-L-ribo-hexopyranoside (1), methyl 6-deoxy-1,3-di-O-methyl-beta-D-ribo-hexosyl-(1-->4)-2,6-dideoxy-3-O-methyl-alpha-D-arabino-hexopyranoside (2), methyl 2,6-dideoxy-3-O-methyl-beta-D-arabino-hexopyranosyl-(1-->4)-6-deoxy-3-O-methyl-alpha-L-ribo-hexopyranoside (3), and 2,6-dideoxy-3-O-methyl-beta-D-arabino-hexopyranosyl-(1-->4)-2,6-dideoxy-3-O-methyl-alpha-D-arabino-hexopyranosyl-(1-->4)-2,6-dideoxy-3-O-methyl-beta-D-lyxo-hexopyranose (4), respectively, by spectral methods.