Sesquiterpene alcohols from Lentinus lepideus

Several sesquiterpene alcohols, mainly possessing a 4,10-dimethyl-7-isopropyldecaline skeleton (cadinols, muurolols, cubenols), have been identified from synthetic liquid cultures of the brown rot fungus Lentinus lepideus. Besides these, trans,trans-farnesol and the bicyclofarnesol drimenol have been found.     

The genetic structure of the A mating-type locus of Lentinula edodes

The Shiitake mushroom, Lentinula edodes (Berk.) Pegler is a tetrapolar basidiomycete with two unlinked mating-type loci, commonly called the A and B loci. Identifying the mating-types in shiitake is important for enhancing the breeding and cultivation of this economically-important edible mushroom. Here, we identified the A mating-type locus from the first draft genome sequence of L. edodes and characterized multiple alleles from different monokaryotic strains. Two intron-length polymorphism markers were developed to facilitate rapid molecular determination of A mating-type. L. edodes sequences were compared with those of known tetrapolar and bipolar basidiomycete species. The A mating-type genes are conserved at the homeodomain region across the order Agaricales. However, we observed unique genomic organization of the locus in L. edodes which exhibits atypical gene order and multiple repetitive elements around its A locus. To our knowledge, this is the first known exception among Homobasidiomycetes, in which the mitochondrial intermediate peptidase (mip) gene is not closely linked to A locus.     

Aquilinan,an acidic polysaccharide from Pteridium aquilinum

A water-soluble, acidic polysaccharide, aquilinan, was isolated from storage rhizomes and young fronds of bracken and shown to be homogeneous. The polysaccharide contained galactose, xylose, fucose and arabinose residues together with chains of repeating α(1-2′)glucuronosylmannose units. A method of correcting the mannose content for degradation during the hydrolysis of the aldobiuronic acid is described.     

Cell wall structure of secreted laccase-silenced strain in Lentinula edodes

Laccase1 (Lcc1) is abundantly secreted from vegetative mycelia into culture medium by Lentinula edodes. Down-regulation of lcc1 in L. edodes results in abnormal hyphal structure and thinner cell wall in mycelia. In this study, we observed the effects of Lcc1 on the hyphal morphology and cell wall structure of L. edodes. A thick cell wall and fibrous layer were clearly observed in the lcc1-silenced strain ivrL1#32, when purified Lcc1 (0.1 mU/mL) was added to the culture medium. The ratio of cell wall polysaccharide contents was compared between the ivrL1#32 strain and the wild-type (WT) strain SR-1, revealing that levels of the alkali soluble β-1,3-1,6-glucan were significantly lower in the lcc1-silenced strain than in the WT strain. Chronological analysis revealed that chitin content in the cell wall did not increase over time, but that the alkali soluble β-1,3-1,6-glucan content increased after Lcc1 secretion in the WT. Taken together, these data suggest that the increased level of β-1,3-1,6-glucan induced by Lcc1 in the mycelial cell wall contributes to increased cell wall thickness and strength.     

On the water-soluble heterogalactan from the fruit bodies of lentinus edodes

The chemical structure of a heterogalactan isolated from the trichloroacetic acid extract of the fruit bodies of Lentinus edodes is reported. It consists of a main chain of (1→6)-linked α-D-galactopyranose residues, part of which are substituted in the 2-position either with single L-fucopyranose or D-mannopyranose residues. However, there is a possible alternative structure of a branched D-galactan in which most of the side-chains are terminated with L-fucose or D-mannose residues.     

Partial structure of a polysaccharide from leaves of Welwitschia mirabilis

Gum-tears from the leaves of Welwitschia mirabilis contain a polysaccharide composed of arabinose, galactose and glucuronic acid as main constituents with xylose, fucose and rhamnose in smaller quantities. Periodate oxidation and permethylation studies indicated that the gum could consist of a framework of glucuronic acid residues linked 1 → 4 and galactose residues linked 1 → 6 and of short chains of arabinose, xylose, fucose and rhamnose linked 1 → 3 to both residues. All rhamnose and fucose and part of arabinose were found as non-reducing terminal units.     

Characterization of an extracellular polysaccharide from a xanthomonas species

An extracellular polysaccharide containing glucose, mannose, D-manno-octulosonic acid (KDO), an unidentified component (X), and acetyl groups in the molar ratio of 1.3:3.8:1.6:1.1:2.9, was obtained from the incubated medium of a Xanthomonas species. The extracellular polysaccharide contained traces of phosphate and nitrogen but no lipid. Mild hydrolysis with 0.025M sulfuric acid released all of the KDO in the polysaccharide and a KDO-free product was obtained, which on hydrolysis with 0.05M sulfuric acid, gave mainly an oligosaccharide containing glucose, mannose, and X in molar ratio of 1:1:1. The reducing end-group of this oligosaccharide was X, and other hexose residues were linked (1 → 4). Compound X seems to be a 6-deoxyhexose that differs from fucose and rhamnose.     

Molecular structure of the polysaccharide exudate from Acacia baileyana F. Muell

Study of the molecular-weight distribution of the raw gum exuded from Acacia baileyana F. Muell., of partially hydrolysed material, and of products of successive Smith-degradations of the gum suggests the occurrence of sub-units having a molecular weight of ～4000. These sub-units consist of β-(1→3)-linked d-galacto-pyranose residues, to most of which are attached residues of l-arabinofuranose or d-galactopyranose; the bulk of the pendant groups are removed by a single Smith-degradation to give a monodisperse fragment of molecular weight 2500. Further, successive degradations by the oxidation-reduction-hydrolysis procedure yielded a galactan which contains about ten hexose residues and which is essentially linear.     

Structural studies on an antitumor polysaccharide from Microellobosporia grisea

The structure of the antitumor polysaccharide from the actinomycete Microellobosporia grisea has been investigated. By methylation and periodate-oxidation studies, the polysaccharide was shown to consist of (nonreducing)d-mannosyl groups, (1→4)-linkedd-glucosyl residues, and 3,6-branched, (1→4)-linkedd-glucosyl residues in the approximate molar ratios of 2:1:1. Periodate oxidation of the polysaccharide, followed by borohydride reduction and mild hydrolysis with acid yielded glycerol, erythritol, 2-O-β-d-glucopyranosyl-d-erythritol, and 5-O-β-d-glucopyranosyl-2,4-bis(hydroxymethyl)-1,3-dioxane, which were isolated in the molar ratios of 2.0:0.14:0.74:0.35. Partial hydrolysis of the polysaccharide gave α-d-Man p-(1→6)-d-Glcp, β-d-Glcp-(1→4)-d-Glcp, α-d-Man p-(1→3)-d-Glcp, and β-d-Glcp-(1→4)-[α-d-Man p-(1→3)-]-d-Glcp. From these results, it is proposed that the polysaccharide is mainly composed of tetrasaccharide repeating-units having the following structure.     

Primary structure of the Klebsiella serotype 16 capsular polysaccharide

The primary structure of the Klebsiella serotype 16 capsular polysaccharide consists of tetrasaccharide repeating-units comprising a/ar3)-α-D-Glcp-(1/ar4)β-D-GlcAp-(1/ar4)-α-L-Fucp-(1/ar chain with a β-D-Galp-(1→ branch at position 4 of the D-glucosyl residue.     

Structural studies of an acidic polysaccharide from Ocimum basilicum seeds

An acidic polysaccharide isolated from the seeds of Ocimum basilicum by DEAE-cellulose fractionation was ～92% pure, having an associated glucan impurity (～8%). The polysaccharide is composed of d-xylose, l-arabinose, l-rhamnose, and d-galacturonic acid in the molar ratios 15:9:7:12, together with traces or galactose and glucose. Methylation analysis indicated that the polysaccharide contained a (1→4)-linked xylan backbone carrying branch-points at C-2 and C-3 of the xylosyl residues, and revealed the structural features of the side chains. Periodateoxidation and Smith-degradation studies support the results of methylation analysis.     

Structural features of an acidic polysaccharide from the mucin of Drosera binata

The polysaccharide from the mucin secreted by the leaves of Drosera binata is composed of l-arabinose, d-xylose, d-galactose, d-man     

First report of an anti-tumor, anti-fungal, anti-yeast and anti-bacterial hemolysin from Albizia lebbeck seeds

A monomeric 5.5-kDa protein with hemolytic activity toward rabbit erythrocytes was isolated from seeds of Albizia lebbeck by using a protocol that involved ion-exchange chromatography on Q-Sepharose and SP-Sepharose, hydrophobic interaction chromatography on Phenyl-Sepharose, and gel filtration on Superdex 75. It was unadsorbed on both Q-Sepharose and SP-Sepharose, but adsorbed on Phenyl-Sepharose. Its hemolytic activity was fully preserved in the pH range 0-14 and in the temperature range 0-100 °C, and unaffected in the presence of a variety of metal ions and carbohydrates. The hemolysin reduced viability of murine splenocytes and inhibited proliferation of MCF-7 breast cancer cells and HepG2 hepatoma cells with an IC₅₀ of 0.21, 0.97, and 1.37 μM, respectively. It impeded mycelial growth in the fungi Rhizoctonia solani with an IC₅₀ of 39 μM but there was no effect on a variety of other filamentous fungi, including Fusarium oxysporum, Helminthosporium maydis, Valsa mali and Mycosphaerella arachidicola. Lebbeckalysin inhibited growth of Escherichia coli with an IC₅₀ of 0.52 μM.     

高效液相色谱法测定金钱菇多糖的单糖组成

采用高效液相色谱法,测定金钱菇多糖的单糖组成.用超声辅助提取金钱菇多糖,通过1-苯基-3-甲基-5-吡唑酮(PMP)衍生水解后的单糖,高效液相色谱法检测衍生物.结果表明：金钱菇多糖由甘露糖(Man)、核糖(Rib)、鼠李糖(Rha)、葡萄糖(Glc)、半乳糖(Gal)、木糖(Xyl)组成,其摩尔为1．00∶0．90∶0．91∶28．03∶1．58∶0．11.该方法快速、简便、重现性好,可用于测定金钱菇多糖的单糖组成.     

The structure of Klebsiella serotype 11 capsular polysaccharide

Using periodate oxidation, methylation analysis, the characterization of oligosaccharides obtained by partial acid hydrolysis, p.m.r. spectroscopy, and analytical ultracentrifugation, the structure of the (mildly alkali-treated) Klebsiella serotype 11 capsular polysaccharide has been elucidated. The tetrasaccharide repeating-unit comprises the sequence ?3)-β-D-Glcp-(1?3)-β-D-GlcUAp-(1?3)-α-D-Galp-(1→ with a 4,6-O-(1-car?yethylidene)-α-D-galactosyl residue linked to O-4 of the glucuronic acid residue. The structural basis for some serological cross-reactions of the Klebsiella K11 antigen is discussed, and it is shown that rabbit antisera against the Klebsiella K11 test-strain predominantly contain K agglutinins specific for branch-terminal 4,6-O-(1-car?yethylidene)-D-galactose.     

Structural study of the extracellular polysaccharide gum from Rhizobium strain CB744

The structure of the extracellular polysaccharide gum from nitrogen-fixing Rhizobium sp. strain CB744 (a member of the slow-growing Cowpea group) has been investigated. Gas-chromatographic analysis of the alditol acetates of the acid hydrolysate showed the gum to be composed of galactose, 4-O-methylgalactose, mannose, and glucose in the molar ratio of 1:2.5:3.5:7.0. The polysaccharide is unusual in that it contains no carbonyl substituent, although such substituents are common amongst polysaccharides produced by the slow-growing group. The native and de-branched polysaccharides were examined by methylation analysis. The anomeric configurations were determined by ¹³C-n.m.r. and oxidation by chromium trioxide. It is concluded that there are two β-(1→4)-linked glycopyranosyl residues for each α-(1→4)-linked mannopyranosyl residue, and that each mannose is substituted at O-6 by a β-galactopyranosyl residue, with 71% of the galactose groups being present as 4-O-methylgalactose.     

Guillonein,an epoxyguaianolide from Guillonea scabra, X-ray structure determination

From the roots of Guillonea scabra a new epoxyguaianolide, guillonein, has been isolated and its structure established by X-ray diffraction analysis. A ¹H NMR spectroscopic study of this new sesquiterpene reveals a conformational difference in its seven-membered ring between the crystal and CDCl₃ solution states. The implications of this conformational change with respect to the C-8 configurations previously assigned to shairidin and desangeloylshairidin are briefly discussed.     

The structure of the polysaccharide O-chain of the LPS from Acinetobacter baumannii strain ATCC 17961

The gram-negative bacterium Acinetobacter baumannii strain ATCC17961 has been used by several laboratories in mouse models of respiratory A. baumannii infection, and a study of the role of its lipopolysaccharide in the pathogenicity is of interest. The structure of the O-deacylated polysaccharide O-chain component of its LPS has been determined by 2D NMR spectroscopy and mass spectrometry methods, and by the structural identification of oligosaccharides obtained by sequential application of the Smith degradation of the O-antigen. The O-chain was determined to be a polymer of a branched pentasaccharide repeating unit composed of 2,3-diacetamido-2,3-dideoxy-d-glucuronic acid, 2-acetamido-2-deoxy-d-glucose, 2-acetamido-2-deoxy-d-galactose, d-glucose, and d-galactose, and has the following structure:     

Structural studies of an acidic polysaccharide from the mucin secreted by Drosera capensis

The polysaccharide of the mucin secreted by the leaves of Drosera capensis is composed of l-arabinose, d-xylose, d-galactose, d-mannose, and d-glucuronic acid in the molar ratio of 3.6:1.0:4.9:8.4:8.2. For structural elucidation, methylation analysis using g.l.c. and g.l.c.-m.s. was performed on the native, the carboxyl-reduced, and the degraded polysaccharides. Partial hydrolysis, periodate oxidation, chromium trioxide oxidation, and uronic acid degradation were also performed on the native and carboxyl-reduced polysaccharides. Partial hydrolysis of the native and carboxyl-reduced polysaccharides gave various oligosaccharides that were characterized and suggest a structure containing a d-glucurono-d-mannan backbone having a repeating unit → 4)-β-d-GlcpA-(1 → 2)-α-d-Manp-(1 →. l-Arabinose and d-xylose are present as nonreducing furanosyl and pyranosyl end-groups, respectively, both attached to O-3 of d-glucuronic acid residues of the backbone. d-Galactose is present as non-reducing pyranosyl end-group linked to O-3 of d-mannose residues.