Shigeru Eda

A new facile methylation method for cell-wall polysaccharides

Abstract A new methylation method involving powdered sodium hydroxide and methyl iodide has been developed for the facile methylation of cell-wall polysaccharides. Commercial cellulose powder, wood cellulose, and unbleached kraft pulp in solution in SO 2 -diethylamine-methyl sulfoxide could be completely methylated. Suspensions of holocelluloses, prepared from spruce and beech wood-meals and containing Nicotiana tabacum (CWM), were almost completely methylated in one step. Some decarboxylation occurred with the latter polymers.

Structural investigation of the arabinoxyloglucan from Nicotiana tabacum

Abstract The structure of tobacco arabinoxyloglucan has been further studied by methylation analysis, by 1 H-, and 13 C-n.m.r., and by fd. mass spectrometry, after complete digestion by cellulase. The results showed the polysaccharide molecule to be composed of two parts; a hexasaccharide component (AraXyl 2 Glc 3 , 1 ) and an unsubstituted (1→4)-β- d -glucan region (4- O -linked glucosyl residues) in the molar ratio of ∼ 1:2. Some heterogeneities of this structure in the arabinofuranosyl sub-group were also found.

A galactoglucomannan from extracellular polysaccharides of suspension-cultured cells of Nicotiana tabacum

Abstract A polysaccharide containing d -xylose, l -arabinose, d -mannose, d -galactose and d -glucose residues in the molar ratio of 0.07:0.16:1.

A galactoglucomannan from cell walls of suspension-cultured tobacco (Nicotiana tabacum) cells

Abstract Cell-wall polysaccharides of suspension-cultured cells of Nicotiana tabacum were fractionated into EDTA-soluble, 5% and 24% potassium hydroxide-soluble, and α-cellulose components. From the 24% potassium hydroxide-soluble fraction, a polysaccharide composed of d -galactose, d -glucose, and d -mannose in approximately equal proportions was purified by ion-exchange chromatography and barium hydroxide precipitation. Methylation analysis, enzymic hydrolysis, and 13 C-n.m.r. studies showed that the polysaccharide was built up of (1→4)-linked, alternating β- d -glucopyranosyl and β- d -mannopyranosyl residues, and that ∼83% of the mannosyl residues were substituted at O-6 by α- d -galactopyranosyl or 2- O -β- d -galactopyranosyl-α- d -galactopyranosyl side-chains.

Structural investigation of a galactoglucomannan from cell walls of tobacco (Nicotiana tabacum) midrib

Abstract Cell-wall polysaccharides of the midrib of Nicotiana tabacum were fractionated into pectin, hemicellulose, and α-cellulose components. From the α-cellulose fraction, a polymer composed of d -galactose, d -glucose, and d -mannose in the molar ratios ∼1:2:4 was extracted by aqueous 25% sodium hydroxide-5% boric acid and purified by barium hydroxide precipitation, ion-exchange chromatography, and gel filtration. Methylation analysis, enzymic degradation, and 13 C-n.m.r. studies showed that the polysaccharide was built up of (1→4)-linked β- d -glucopyranosyl and β- d -mannopyranosyl residues in the molar ratio ∼1:2, and that ∼14% of the d -mannosyl residues were substituted at O-6 by α- d -galactopyranosyl or 2- O -β- d -galactopyranosyl-α- d -galactopyranosyl side-chains.

Structural studies of the O-antigen of the lipopolysaccharide from an avirulent strain (M4S) of Pseudomonas solanacearum.

The structure of the O-antigen of the lipopolysaccharide from an avirulent strain (M4S) of Pseudomonas solanacearum has been investigated by methylation analysis, n.m.r. spectroscopy, and N-deacetylation-deamination, followed by analysis and controlled Smith-degradation of the product. These studies demonstrate that the O-antigen is composed of a tetrasaccharide repeating-unit having the following structure: ----3)-alpha-D-GlcpNAc-(1----2)-alpha-L-Rhap-(1----2)-alpha- L-Rhap-(1----3)- alpha-L-Rhap-(1----.

Studies on the Nature of Lignin - Carbohydrate Bonding

Abstract A lignin - carbohydrate complex (LCC) fraction which was initially extracted with dimethyl sulfoxide from birch residual wood meal after stepwise MWL extraction (total yield 28%), contained about 7% qalacturonic acid together with about 4% glucuronic acid. Although galacturonic acid residue is well known to be a component of hardwood xylan, it also suggests the possibility of the existence of pectic substance in this LCC fraction. The nature of galacturonic acid in this LCC fraction was characterized by means of two purified pectinases, endo-polygalacturonase and endo-pectin lyase. It was concluded that most of the carbohydrate in this LCC fraction, especially xylan, is combined with lignin through pectic substance.

Transglucosylation into Stevioside by the Enzyme System from Streptomyces sp.

The enzyme system from Streptomyces sp. W19–1 formed several kinds of transfer products (TPs) when incubated in the presence of both stevioside (ST) and curdlan. Three of the major TPs (A, B, and C) were separated and purified using HP-20 column chromatography, gel filtration on TOYOPEARL HW-40F, and preparative high-performance liquid chromatography.The structures of the three were identified by chemical and enzymatic methods; A is 13-O-β-sophorosyl-19-O-β-laminaribiosyl steviol, B is 13-O-β-32-β-glucosylsophorosyl-19-O-β-glucosyl steviol, and C is 13-O-β-sophorosyl-19-O-β-laminaritriosyl steviol. The three were obtained for the first time in a pure state.

An acidic xylan from extracellular polysaccharides of suspension-cultured cells of Nicotiana tabacum

Abstract An acidic xylan was isolated from the extracellular polysaccharides of suspension-cultured tobacco cells. Its structure was investigated by methylation analysis and 13 C NMR spectroscopy and was shown to consist of a main chain of β-(1→4)-linked D -xylopyranosyl residues to which were attached as side-chains, α- D -glucuronic acid residues at O-2.