Yukio Akiyama

An extracellular arabinogalactan-protein from Nicotiana tabacum

Abstract An extracellular arabinogalactan-protein was obtained from suspension-cultured tobacco cells. It seemed to be a homogeneous preparation from the results of gel-filtration, ultracentrifugation and disc gel electrophoresis. Its MW was estimated to be 2.24 × 10 5 and its sedimentation coefficient ( S 20,w ) was calculated to be 5.07 S. It consisted of arabinose (40.0%), galactose (36.2%), rhamnose (0.8 %), glucuronic acid (10.0 %), glucosamine (0.2 %), galactosamine (0.1%) and protein (5.5 %). The sugar moiety appeared to be a typical arabino-3,6-galactan. A d -glucuronic acid residue was present as the non-reducing terminal group and was attached to C(O)-6 of a d -galactosyl residue by β-linkage.

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.

Studies on the taste modifiers. I. Purification and structure determination of sweetness inhibiting substance in leaves of ziziphus jujuba

Abstract The sweetness Inhibiting substance (ziziphin) containing in leaves of the plant Ziziphua jujuba (Rhamnaceae) was isolated in pure state. The chemical structure was established as 3-0-(4-0-α-L-rhamnopyranosyl-α-L-arabinopyranosyl)-20-0-(2,3- di-0-acetyl)-α-L-rhamnopyranosyljujubogenin 1 on the basis of spectral and chemical evidence.

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.

Methylation analysis of extracellular polysaccharides from suspension-cultured cells of Nicotiana tabacum

Abstract The soluble extracellular polysaccharides (ECP) of suspension-cultured tobacco cells were fractionated by DEAE-Sephadex CC into seven sub-fractions. Su

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----.

An arabinoxyloglucan from extracellular polysaccharides of suspension-cultured tobacco cells

Abstract An arabinoxyloglucan (AXG) isolated from extracellular polysaccharide of suspension-cultured tobacco cells was investigated by methylation analysis, partial acid hydrolysis and 13 C NMR spectroscopy. It was found that the AXG is structurally similar to that isolated from the midrib of tobacco leaves.

A pectic polysaccharide from cell walls of tobacco (Nicotiana tabacum) mesophyll

Abstract A pectic polysaccharide has been purified from the pectin fraction of the cell-wall material of tobacco mesophyll by ion-exchange chromatography and gel filtration, and shown to contain d -galacturonic acid, l -rhamnose, l -arabinose, and d -galactose in the molar ratios 88.2:2.8:3.1:5.9. The polysaccharide contains at least three regions, namely, galacturonan, rhamnogalacturonan, and galactan.

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.