Some structural features of the heteropolysaccharides of Candida bogoriensis

1968 ◽  
Vol 46 (21) ◽  
pp. 3407-3411 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer

The two exocellular polysaccharides of Candida bogoriensis contain D-mannose, D-fucose, L-rhamnose, D-glucuronic acid, and D-galactose residues. The main heteropolymer (> 80%) has an α-D-(1 → 3)-linked mannan main-chain as shown by successive Smith degradations. Partial hydrolysis of the heteropolymers provided several methylpentose-containing oligosaccharide fragments corresponding to possible side-chain components.

1959 ◽  
Vol 37 (5) ◽  
pp. 922-929 ◽  
Author(s):  
A. L. Currie ◽  
T. E. Timell

The seed hairs of kapok (Ceibapentandra) on alkaline extraction have yielded a hemicellulose composed of xylose and uronic acid residues. Partial hydrolysis of the polysaccharide gave 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose, 4-O-methyl-D-glucuronic acid, and, probably, galacturonic acid. Hydrolysis of the fully methylated hemicellulose yielded a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid)-3-O-methyl-D-xylopyranose in a molar ratio of 1.1:38:1:6. The number-average D.P. of the native and the methylated polysaccharides was 177 and 124, respectively. On the basis of this and other evidence it is suggested that the average hemicellulose molecule contains approximately 180 1,4-linked β-D-xylopyranose residues, one eighth of which carry a single terminal side chain of 4-O-methyl-D-glucuronic acid, attached through an α-glycosidic bond to C2 of the xylose. The xylan framework contains, on the average, slightly less than two branching points per macromolecule, most of them probably originating from C3. The number of acid side chains and branches is twice as large as that of the otherwise similar 4-O-methyl glucuronoxylan present in the seed hairs of milkweed floss.


1958 ◽  
Vol 36 (11) ◽  
pp. 1467-1474 ◽  
Author(s):  
J. K. Gillham ◽  
T. E. Timell

The wood of white elm (Ulmusamericana) has been found to contain less xylan than most other hardwoods. Partial hydrolysis of the hemicellulose component yielded an aldotriouronic acid, a glucuronosyl xylose, 2-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-xylopyranose, 4-O-methyl-D-glucuronic acid, and galacturonic acid.Hydrolysis of the fully methylated polysaccharide gave a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyluronic acid)-3-O-methyl-D-xylopyranose in a molar ratio of 6:124:1:14. The number-average degree of polymerization of the methylated hemicellulose was 133 and that of the native polymer 185. On the basis of this and other evidence it is suggested that the xylan is linear and contains 185 1,4-linked β-D-xylopyranose residues, every seventh of which carries a single terminal side chain of 4-O-methyl-D-glucuronic acid attached by an α-glycosidic bond through C2 of the xylose. The number of acid groups is larger than in other hardwood hemicelluloses so far studied.


1956 ◽  
Vol 34 (3) ◽  
pp. 338-344 ◽  
Author(s):  
E. L. Falconer ◽  
G. A. Adams

Partial hydrolysis of hemicellulose B from oat hulls yielded two aldobiouronic acids, which were identified as 2-O-(4-O-methyl-α-D-glucopyruronosyl)-D-xylose and 2-O-(α-D-glucopyruronosyl)-D-xylose respectively. In addition, two aldotriouronic acids were isolated, one yielding on hydrolysis xylose and 4-O-methyl-glucuronic acid, and the other, xylose, galactose, and glucurone.


1974 ◽  
Vol 139 (3) ◽  
pp. 633-643 ◽  
Author(s):  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson

Studies of the lipopolysaccharide of Pseudomonas alcaligenes strain BR 1/2 were extended to the polysaccharide moiety. The crude polysaccharide, obtained by mild acid hydrolysis of the lipopolysaccharide, was fractionated by gel filtration. The major fraction was the phosphorylated polysaccharide, for which the approximate proportions of residues were; glucose (2), rhamnose (0.7), heptose (2–3), galactosamine (1), alanine (1), 3-deoxy-2-octulonic acid (1), phosphorus (5–6). The heptose was l-glycero-d-manno-heptose. The minor fractions from gel filtration contained free 3-deoxy-2-octulonic acid, Pi and PPi. The purified polysaccharide was studied by periodate oxidation, methylation analysis, partial hydrolysis, and dephosphorylation. All the rhamnose and part of the glucose and heptose occur as non-reducing terminal residues. Other glucose residues are 3-substituted, and most heptose residues are esterified with condensed phosphate residues, possibly in the C-4 position. Free heptose and a heptosylglucose were isolated from a partial hydrolysate of the polysaccharide. The location of galactosamine in the polysaccharide was not established, but either the C-3 or C-4 position appears to be substituted and a linkage to alanine was indicated. In its composition, the polysaccharide from Ps. alcaligenes resembles core polysaccharides from other pseudomonads: no possible side-chain polysaccharide was detected.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3654
Author(s):  
Rayya A. Al-Balushi ◽  
Ashanul Haque ◽  
Idris J. Al-Busaidi ◽  
Houda Al-Sharji ◽  
Muhammad S. Khan

Metalla-ynes and poly(metalla-ynes) have emerged as unique molecular scaffolds with fascinating structural features and intriguing photo-luminescence (PL) properties. Their rigid-rod conducting backbone with tunable photo-physical properties has generated immense research interests for the design and development of application-oriented functional materials. Introducing a second d- or f-block metal fragment in the main-chain or side-chain of a metalla-yne and poly(metalla-yne) was found to further modulate the underlying features/properties. This review focuses on the photo-physical properties and opto-electronic (O-E) applications of heterometal grafted metalla-ynes and poly(metalla-ynes).


1963 ◽  
Vol 41 (11) ◽  
pp. 2826-2835 ◽  
Author(s):  
V. M. Parikh ◽  
J. K. N. Jones

The extracellular polysaccharide of the Azotobacter indicum has been shown to be a mixture of two polymers of which the acidic polymer was a major fraction. The acidic polymer contained D-glycero-D-mannoheptose in the molar ratio of 1:1:1 plus traces of mannose. It consumed 1 mole of sodium metaperiodate per mole of an average anhydroaldose unit and released 0.95 moles of formaldehyde per anhydroheptose unit. Reduction of the oxidized polymer followed by hydrolysis yielded D-glucose, glycerose, glycolaldehyde, and glycerol. Complete fission of the methylated polymer yielded 2,3-di-O-methyl-D-glucuronic acid, 2,4,6,-tri-O-methyl α-D-glucose and 3,4,6,7-tetra-O-methyl D-glycero-D-mannoheptose. Partial hydrolysis of the methylated polymer produced a methylated aldotriouronic acid composed of 1 mole each of 2,3-di-O-methyl-D-glucuronic acid, 2,4,6-tri-O-methyl-D-glucose and 3,4,6,7-tetra-O-methyl D-glycero-D-mannoheptose. A methylated aldobiouronic acid was also produced and was shown to be composed of 2,3-di-O-methyl-D-glucuronic acid and 2,4,6-tri-O-methyl D-glucose.On the basis of these results it is proposed that the polysaccharide is a linear molecule composed of repeating units of D-glucuronic acid, D-glucose, and D-glycero-D-mannoheptose.


1963 ◽  
Vol 41 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
A. R. Mills ◽  
T. E. Timell

An arabino-4-O-methylglucuronoxylan (10:70:12), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.2:1:3) have been isolated in yields of 8.0, 1.0, and 8.1% from the wood of Engelmann spruce (Picea engelmanni). The xylan consisted of a linear framework of (1 → 4)-linked β-D-xylose residues to which were directly attached single side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues. The galactoglucomannans were both composed of a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues, some of which carried directly attached side chains of (1 → 6)-linked α-D-galactopyranose residues. Partial hydrolysis of the water-soluble galactoglucomannan yielded, among other oligosaccharides, a trisaccharide composed of galactose, glucose, and mannose residues. It is concluded that the main polysaccharides in the wood of Engelmann spruce are the same as those in most other gymnosperms. In the bark of this tree, the water-soluble galactoglucomannan is replaced by one or several polysaccharides of an entirely different composition.


1959 ◽  
Vol 37 (5) ◽  
pp. 893-898 ◽  
Author(s):  
T. E. Timell

Partial hydrolysis of the main hemicellulose constituent of sugar maple (Acersaccharum) has yielded D-xylose, D-galacturonic acid, 4-O-methyl-D-glucuronic acid, and 2-O-(4-O-methyl-α-D-glucosyluronic acid)-D-xylose. Hydrolysis of the fully methylated polysaccharide gave a mixture of 2-O- and 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucosyluronic acid)-3-O-methyl-D-xylose in a mole ratio of 3:111:1:12. The number-average degrees of polymerization of the native and the methylated polysaccharide were 205 and 149, respectively. These data indicate that the hemicellulose is composed of a linear chain of 1,4-linked β-D-xylose residues and that on the average every tenth residue of the chain carries a terminal 4-O-methyl-D-glucuronic acid residue attached through its C2. The structure of the polysaccharide is similar to that of the main hemicellulose component of European beech, white birch, and yellow birch.


1973 ◽  
Vol 51 (18) ◽  
pp. 3021-3026 ◽  
Author(s):  
Yuen-Min Choy ◽  
Guy G. S. Dutton

Methylation, periodate oxidation, and partial hydrolysis studies on the capsular polysaccharide of Klebsiella K-type 56 show the structure to be a repeating unit consisting of[Formula: see text]The nature of the anomeric linkages was determined by p.m.r. spectroscopy of isolated oligosaccharides. The position of the L-rhamnose side chain was defined by characterization of the di- and tetrasaccharides obtained by partial hydrolysis of the fully methylated polysaccharide.This structure represents the first capsular polysaccharide lacking uronic acid to be studied in the genus Klebsiella.


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