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S G Wilkinson

Publications and source records attributed to S G Wilkinson.

At least 91 records · Page 5Linked to original sources

Structural studies of a mannitol teichoic acid from the cell wall of bacterium N.C.T.C. 9742.

Degradative and n.m.r.-spectroscopic studies have been carried out on a novel mannitol teichoic acid extracted from the cell wall of bacterium N.C.T.C. 9742, for which the name Brevibacterium iodinum has been proposed. The backbone of the polymer is a poly(D-mannitol phosphate) containing 1----6 phosphodiester linkages. In most residues, pyruvic acid is acetal-linked to positions 4 and 5 of the mannitol. About half of the mannitol residues carry a beta-D-glucopyranosyl substituent at position 2. The glucosylmannitol was isolated and thoroughly characterized. At least 24 products were detected by ion-exchange chromatography and paper electrophoresis after alkaline hydrolysis of the polymer. Not all of these products could be identified. The main mechanistic pathways for depolymerization by the cleavage of phosphodiester linkages during alkaline hydrolysis involved (a) participation by the 2-hydroxy group and a cyclic phosphodiester intermediate (leading to a series of mannitol-based products) and (b) participation by the 3-hydroxy group in the cyclization of mannitol (leading to a series of products based on 1,4-anhydromannitol). The presence of glycerol phosphates in hydrolysates could be ascribed either to a linkage unit or to a separate glycerol teichoic acid. The mannitol teichoic acid was absent from the cell walls of Brevibacterium linens and Brevibacterium epidermis (one strain of each was examined).

Biopolymers↗

Composition of O-antigenic lipopolysaccharides from Enterobacter cloacae.

Analyses have been carried out on lipopolysaccharides (LPS) from 14 strains of Enterobacter cloacae representing different O serotypes. All of the products appeared to have a composition and architecture typical of enterobacterial LPS, but points of interest include the absence of phosphate residues from the core oligosaccharide, the presence of both L-glycero-D-mannoheptose and D-glycero-D-mannoheptose (ratio usually about 4:1), and the presence in lipid A of small amounts of fatty acids with odd numbers of carbon atoms (mainly C13) in addition to tetradecanoic acid and 3-hydroxytetradecanoic acid. Monosaccharides identified as components of polymeric fractions from the LPS were glucose, galactose, mannose, rhamnose, glucosamine, galactosamine, fucosamine, and galacturonic acid. Most polymeric fractions also probably contained an O-acetyl substituent. Closely similar chemotypes found for the polymeric fractions from the LPS of cross-reacting serotypes support the view that these fractions contain the O-antigenic determinants and represent the side chains of the LPS.

Antigens, Bacterial↗

The lipopolysaccharide from Pseudomonas aeruginosa NCTC 8505. Structure of the O-specific polysaccharide.

Structural studies have been carried out on the O-specific fraction from the lipopolysaccharide of Pseudomonas aeruginosa NCTC 8505, Habs serotype 03. The O-specific polysaccharide has a tetrasaccharide repeating-unit containing residues of L-rhamnose (Rha), 2-acetamido-2-deoxy-D-glucose (GlcNAc), 2-acetamido-2-deoxy-L-galacturonic acid (GalNAcA), and 2,4-diacetamido-2,4,6-trideoxy-D-glucose (BacNAc2). The following structure has been assigned to the repeating-unit: leads to 3)Rhap(beta 1 leads to 6)GlcpNAc(alpha 1 leads to 4)GalpNAcA(alpha 1 leads to 3)BacpNAc2(alpha 1 leads to. The parent lipopolysaccharide is a mixture of S, R, and SR species, and its high phosphorus content is partly due to the presence of triphosphate residues, as found for other lipopolysaccharides from P. aeruginosa. In addition to phosphorus, heptose, a 3-deoxyoctulosonic acid, and amide-bound alanine, the core oligosaccharide contains glucose, rhamnose, and galactosamine (molar proportions 3:1:1). The rhamnose and part of the glucose are present as unsubstituted pyranoside residues: other glucose residues are 6-substituted.

Carbohydrate Sequence↗

Lipopolysaccharides from Pseudomonas maltophilia: composition of the lipopolysaccharide and structure of the side-chain polysaccharide from strain N.C.I.B. 9204.

Lipopolysaccharide was extracted from defatted cell-walls of Pseudomonas maltophilia N.C.I.B. 9204. The major fatty acid components were 9-methyldecanoic acid, 2-hydroxy-9-methyldecanoic acid, 3-hydroxy-9-methyldecanoic acid, 3-hydroxy-dodecanoic acid, and 3-hydroxy-11-methyldodecanoic acid. Monosaccharide components of the phosphorylated core-oligosaccharide were D-glucose, D-mannose, D-galacturonic acid, 2-amino-2-deoxyglucose, and a 3-deoxyoctulosonic acid. The putative O-specific polysaccharide was composed mainly of 2-amino-2-deoxy-D-glucose, D-arabinose, and 6-deoxy-L-talose, but also contained an O-acetyl group and small proportions of rhamnose and 6-deoxy-3-O-methyltalose. Degradative and n.m.r. (1H and 13C) studies showed that the polymer had a branched trisaccharide repeating-unit with the following structure; the O-acetyl group was tentatively assigned to C-2 of the 6-deoxytalopyranosyl residue. (Formula: see text).

Carbohydrate Conformation↗

Structural studies of the O-specific polysaccharide from Serratia marcescens N.C.T.C. 1377.

The putative O-specific polysaccharide of Serratia marcescens N.C.T.C. 1377 is a partially acetylated glucorhamnan. By means of 1H- and 12C-n.m.r. spectroscopy, methylation analysis, and periodate oxidation, it was shown that the polymer has a disaccharide repeating-unit for which the following structure is proposed: leads to 4)-alpha-D-Glcp-(1 leads to 3)-beta-L-Rhap-(1-leads. O-Acetyl groups are probably located at C-2 of the rhamnopyranosyl residues. Except for the extent of O-acetylation, the polysaccharide is identical with the corresponding product from S. marcescens Bizio (A.T.C.C. 264), for which a different structure has previously been proposed.

Magnetic Resonance Spectroscopy↗

Lipopolysaccharides from Pseudomonas maltophilia. Structural studies of the side-chain, core, and lipid-A regions of the lipopolysaccharide from strain NCTC 10257.

Structural studies have been carried out on the O-specific polysaccharide, the core oligosaccharide, and the lipid A from the lipopolysaccharide of Pseudomonas maltophilia NCTC 10257. By means of 13C nuclear magnetic resonance spectroscopy, a tetrasaccharide repeating-unit for the O-specific polymer has been confirmed. However, the data suggest that the L-rhamnopyranosyl residue at the branching point has the alpha configuration rather than beta as proposed previously [Neal, D.J. and Wilkinson, S.G. (1979) Carbohydr. Res. 69, 191-201]. The core oligosaccharide contains residues of D-glucose, D-mannose phosphate, D-galactosamine (not N-acetylated), D-galacturonic acid, and a 3-deoxyoctulosonic acid (but no aldoheptose). A partial structure for the oligosaccharide is proposed. Lipid A is based on phosphorylated glucosamine residues, with N-fatty acyl and O-fatty acyl substituents. The major fatty acids are 9-methyldecanoic acid, 2-hydroxy-9-methyldecanoic acid, 3-hydroxy-9-methyldecanoic acid (each ester-linked), 3-hydroxydodecanoic acid, and 3-hydroxy-11-methyldodecanoic acid (both mainly amide-linked). The results of this study provide further evidence for a relationship between P. maltophilia and some Xanthomonas species.

Chemical Phenomena↗

Lipid composition and chemotaxonomy of Pseudomonas putrefaciens (Alteromonas putrefaciens).

The major polar lipids in cells of Pseudomonas putrefaciens NCIB 10472 grown on nutrient agar were phosphatidylethanolamine, phoisphatidylglycerol, a glucosyldiacylglycerol, a glucuronosyldiacylglycerol and an ornithine amide lipid. An additional phospholipid, tentatively identified as acyl phosphatidylglycerol or bis-phosphatidic acid, was a trace component of the wall lipids from broth cultures, which lacked the glycolipids and the ornithine amide lipid. The wall lipids from broth cultures of three further strains of P. putrefaciens (NCIB 10471, NCIB 11156 and NCTC 10737) contained all of the above lipids, and in two cases (strains NCIB 10471 and NCIB 11156) had an unusually high content of free fatty acid. Fatty acid compositions of the extractable lipids were qualitatively similar for all four strains: the major components were iso-pentadecanoic acid, pentadecanoic acid, a cis-heptadecenoic acid and a cis-hexadecenoic acid. Anteiso fatty acids were minor components in strain NCIB 10472. Lipid mixtures in which the ornithine amide lipid was present also contained small amounts of beta-hydroxy fatty acids: in strain NCIB 10472 the major ones were the straight-chain and iso-branched C16 acids. Lipopolysaccharides from all four strains had similar, complex fatty acid compositions. The major non-hydroxy acids were the straight-chain and iso-branched C13 acids. beta-Hydroxy acids common to all strains included the straight-chain C11, C12, C13, C14 and C15 acids, together with branched-chain C13 and C15 acids probably belonging to the iso series. The lipopolysaccharide from strains NCIB 10472 also contained C12 and C14 hydroxy acids of the same series, and small amounts of C13 and C15 beta-hydroxy acids probably belonging to the anteiso series. The close resemblance in both polar lipid and fatty acid compositions between strains of P. putrefaciens and Pseudomonas rubescens is further evidence that these species are synonymous. Significant differences between the lipids and fatty acids of P. putrefaciens and those reported for a strain of Alteromonas haloplanktis do not harmonize with a proposal to transfer the former organism to the genus Alteromonas.

Fatty Acids↗

Polar lipids of Pseudomonas vesicularis. Presence of a heptosyldiacylglycerol.

The individual polar lipids produced by Psuedomonas vesicularis NCTC 10 900 during surface culture have been isolated. The major lipids are phosphatidylglycerol, a phosphatidyl-alpha-D-glucopyranosyldiacylglycerol, 1,2-di-O-acyl-3-O-alpha-D-glucopyranosylglycerol. 1,2-di-O-acyl-3-O-alpha-D-glucopyranuronosylglycerol, and 1,2-di-O-acyl-3-O[beta-D-glucopyranosyl-(1 yields 4)-alpha-D-glucopyranuronosyl]glycerol. These are also the major polar lipids of Pseudomonas diminuta. Additional lipids present in P. vesicularis are unidentified carotenoids and a novel lipid characterised as 1,2-di-O-acyl-3-O-alpha-D-glycero-D-glucoheptopyranosylglycerol. A cis-octadecenoic acid and hexadecanoic acid are the major fatty acids: C15 and C17 acids are significant minor components. The fatty methyl ester fractions derived from three of the lipids (most notably the glucosyldiacylglycerol) contained substantial amounts of a compound with chromatographic properties resembling those of an octadecenoic ester: the identity and origin or this compound remained uncertain.

Diglycerides↗

Lipopolysaccharides from Pseudomonas maltophilia: structural studies of the side-chain polysaccharide from strain N.C.T.C. 10257.

A lipopolysaccharide has been isolated from Pseudomonas maltophilia N.C.T.C. 10257. Monosaccharide components identified were L-rhamnose, 3-O-methyl-L-xylose, L-xylose, D-glucose, D-mannose, D-galacturonic acid, 2-amino-2-deoxy-galactose, 2-amino-2-deoxyglucose, and a 3-deoxy-2-octulosonic acid. Heptose was absent. In this and other respects, the lipopolysaccharide resembles the corresponding products from Xanthomonas species. Mild hydrolysis of the lipopolysaccharide with acid, followed by chromatography of the water-soluble products on Sephadex G-50, gave a polymeric, "side-chain" fraction containing rhamnose, 3-O-methylxylose, and xylose residues in the molar rations approximately 15:4:1. Methylation analysis, periodate oxidation, Smith degradation, and oxidation with chromium trioxide were the principal methods used in the study of this fraction. The following structure is proposed for the characteristic repeating-unit of the polymer.

Chemical Phenomena↗

Amino components of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 8505. Presence of 2,4-diamino-2,4,6-trideoxy-D-glucose.

Configurations were determined for previously identified amino components of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 8505. Glucosamine and galactosamine belong to the D-series, and alanine and aminogalacturonic acid to the L-series. An additional amino component was identified as 2,4-diamino-2,4,6-trideoxy-D-glucose. This compound may be a characteristic component of the O-specific chain in lipopolysaccharides of strains of Pseudomonas aeruginosa belonging to Habs sero-group 3.

Alanine↗

Studies of lipopolysaccharides from Pseudomonas aeruginosa.

Lipopolysaccharides from 13 strains of Pseudomonas aeruginosa representing seven serotypes of the Habs scheme have been analysed. The lipid A fractions, obtained by mild acid hydrolysis of the lipopolysaccharides, contained phosphorylated glucosamine residues substituted with dodecanoic, hexadecanoic, 2 hydroxydodecanoic, 3-hydroxydecanoic, and 3-hydroxydodecanoic acids (hexadecanoic acid and 2-hydroxdodecanoic acid were absent from one lipid A). Low-molecular-weight solutes released during the mild hydrolyses included 2-keto-3-deoxyoctonic acid, inorganic orthophosphates and pyrophosphates, ethanolamine mono, pyro and triphosphates. For most strains two polysaccharide fractions, one of which appeared to be the common core polysaccharide, were obtained. The major identifiable components and their approximate proportions in the core polysaccharides were glucose (3-4), rhamnose (1), galactosamine (1), alanine (1-1.5), phosphorus (4-6) and heptose (1-2). Rhamnose was absent from one polysaccharide another lacked both rhamnose and alanine but contained glucosamine. Small amounts of various amino sugars found in other core polysaccharides could be associated with the presence of higher-molecular-weight material. Such material was isolated from strain NCIB 8626. The high-molecular-weight polysaccharides obtained from ten strains were probably heterogeneous and consisted mainly of amino compounds, though rhamnose was a major component of four polysaccharades and arabinose was present in another. Fucosamine was the most common amino sugar, but quinovosamine, glucosamine, galactosamine, a possible aminohexuronic acid and unidentified amino compounds were also detected. The results of the survey are discussed in terms of the serological classification of the bacteria and of their sensitivity to EDTA.

Alanine↗

Studies of polysaccharide fractions from the lipopolysaccharide of Pseudomonas aeruginosa N.C.T.C. 1999.

Two polymeric water-soluble fractions were isolated by gel filtration after mild acid hydrolysis of the lipopolysaccharide from Pseudomonas aeruginosa N.C.T.C. 1999. The fraction of higher molecular weight retained the O-antigenic specificity of the lipopolysaccharide and may be 'side-chain' material. This fraction was rich in N (about 10%) and gave several basic amino compounds on acid hydrolysis; fucosamine (at least 2.8% w/w) was the only specifc component identified. The fraction of lower molecular weight was a phosphorylated polysaccharide apparently corresponding to 'core' material. The major components of this fraction and their approximate molar proportions were: glucose (3-4); rhamnose (1); heptose (2); 3-deoxy-2-octulonic acid (1); galactosamine (1); alanine (1-1.5); phosphorus (6-7). In the intact lipopolysaccharide this fraction was probably linked to lipid A via a second residue of 3-deoxy-2-octulonic acid, and probably also contained additional phosphate residues and ethanolamine. The residues of 3-deoxy-2-octulonic acid were apparently substituted in the C-4 or C-5 position, and the phosphorylated heptose residues in the C-3 position. The rhamnose was mainly 2-substituted, though a little 3-substitution was detected. The glucose residues were either unsubstituted or 6-substituted. Four neutral oligosaccharides were produced by partial acid hydrolysis and were characterized by chemical, enzymic, chromatographic and mass-spectrometric methods of analysis. The structures assigned were: Glcpalpha1-6Glc; Glcpbeta1-2Rha; Rhapalpha1-6Glc; Glcpbeta1-2Rhapalpha1-6Glc. The galactosamine was substituted in the C-3 or C-4 position, the attachment of alanine was indicated, and evidence that the amino sugar linked the glucose-rhamnose region to the 'inner core' was obtained.

Alanine↗

Studies of the polysaccharide fraction from the lipopolysaccharide of Pseudomonas alcaligenes.

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, P(i) and PP(i). 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.

Alanine↗