Life Sciences Research for Lifelong Health

Publications david-oxley

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Primary iron overload with inappropriate hepcidin expression in V162del ferroportin disease.
Zoller H, McFarlane I, Theurl I, Stadlmann S, Nemeth E, Oxley D, Ganz T, Halsall DJ, Cox TM, Vogel W

Ferroportin disease (hemochromatosis type 4) is a recently recognized disorder of human iron metabolism, characterized by iron deposition in macrophages, including Kupffer cells. Mutations in the gene encoding ferroportin 1, a cellular iron exporter, are responsible for this iron storage disease, inherited as an autosomal dominant trait. We present clinical, histopathological, and radiological findings in a family with the most common ferroportin mutation, V162del. In the index case, the disorder is characterized by abundant deposition of hemosiderin in all tissues investigated (mesenteric lymph node, liver, gastric and duodenal mucosa, and also in squamous cell carcinoma of the lung). The radiological findings indicated the presence of excess iron in bone marrow and spleen. Despite a significant burden of iron, no features of chronic liver disease were found in affected members of the family, including individuals aged up to 80 years. Hyperferritinemia greater than 1,000 microg/L was a penetrant biochemical finding before the second decade in life and was associated with significantly increased serum concentrations of pro-hepcidin that correlated positively with urinary hepcidin concentrations. In conclusion, the systemic iron burden in ferroportin disease is not a sufficient cause for chronic liver disease. In patients with most, but not all, ferroportin mutations, retention of iron in macrophages of the liver and other organs may protect against damage to parenchymal cells. Finally, macrophage iron storage in ferroportin disease is associated with elevated serum pro-hepcidin levels.

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Hepatology (Baltimore, Md.), 42, 0270-9139, 466-72, 2005

PMID: 15986403

Beta-elimination: an unexpected artefact in proteome analysis.
Herbert B, Hopwood F, Oxley D, McCarthy J, Laver M, Grinyer J, Goodall A, Williams K, Castagna A, Righetti PG

Two persistent myths, ingrained in the electrophoretic literature of the last thirty years, namely carbamylation and deamidation, have been recently dispelled (Herbert et al., J. Proteome Res. 2002, in press). We report here, for the first time, a noxious and unexpected artefact in proteome analysis: beta-elimination (or desulfuration), which results on the loss of an H(2)S group (34 Da) from cysteine (Cys) residues for protein focusing in the alkaline pH region. With such an elimination event, a dehydro alanine residue is generated at the Cys site. In turn, the presence of a double bond in this position elicits lysis of the peptide bond, generating a number of peptides of fairly large size from an intact protein. The first process seems to be favored by the electric field, probably due to the continuous harvesting of the SH(-) anion produced. The only remedy found to this noxious degradation pathway is the reduction and alkylation of all Cys residues prior to their exposure to the electric field. Alkylation appears to substantially reduce both beta-elimination and the subsequent amido bond lysis.

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Proteomics, 3, 1615-9853, 826-31, 2003

PMID: 12833505

Carbamylation of proteins in 2-D electrophoresis--myth or reality?
McCarthy J, Hopwood F, Oxley D, Laver M, Castagna A, Righetti PG, Williams K, Herbert B

Carbamylation is widely quoted as being a problem in 2-D gel analysis and the associated sample preparation steps. This modification occurs when iso-cyanate, a urea break-down product, covalently modifies lysine residues, thus inducing a change in isoelectric point. Urea is used at up to 9 M concentrations in sample preparation and 2-D gels because of its ability to disrupt protein structure and effect denaturation without the need for ionic surfactants such as SDS. We have studied carbamylation using 7 M urea and 2 M thiourea, under a range of experimental temperatures to establish when, and if, it occurs and what can be done to minimize the modification. The actual time required for protein extraction from a tissue is usually short compared to the time required for procedures such as reduction and alkylation and IPG rehydration and focusing. Therefore, it is the temperature during these post-extraction procedures that is the most critical factor. Our experiments have shown that carbamylation does not occur during electrophoresis in the presence of urea, even with prolonged run-times. However, under poorly controlled sample preparation and storage conditions, it can become a major event.

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Journal of proteome research, 2, 1535-3893, 239-42, 0

PMID: 12814262

Identification of two highly sialylated human tear-fluid DMBT1 isoforms: the major high-molecular-mass glycoproteins in human tears.
Schulz BL, Oxley D, Packer NH, Karlsson NG

Human open eye tear fluid was separated by low-percentage SDS/PAGE to detect high-molecular-mass protein components. Two bands were found with apparent molecular masses of 330 and 270 kDa respectively. By peptide-mass fingerprinting after tryptic digestion, the proteins were found to be isoforms of the DMBT1 gene product, with over 30% of the predicted protein covered by the tryptic peptides. By using gradient SDS/agarose/polyacrylamide composite gel electrophoresis and staining for glycosylation, it was shown that the two isoforms were the major high-molecular-mass glycoproteins of >200 kDa in human tear fluid. Western blotting showed that the proteins expressed sialyl-Le(a). After the release of oligosaccharides by reductive beta-elimination from protein blotted on to PVDF membrane, it was revealed by liquid chromatography-MS that the O-linked oligosaccharides were comprised mainly of highly sialylated oligosaccharides with up to 16 monosaccharide units. A majority of the oligosaccharides could be described by the formula dHex(0-->2)NeuAc(1-->)(x)Hex(x)HexNAc(x)(-ol), x=1-6, where Hex stands for hexose, dHex for deoxyhexose, HexNAc for N-acetylhexosamine and NeuAc for N-acetylneuraminate. The number of sialic acids in the formula is less than 5. Interpretation of collision-induced fragmentation tandem MS confirmed the presence of sialic acid and suggested the presence of previously undescribed structures carrying the sialyl-Le(a) epitopes. Small amounts of neutral and sulphated species were also present. This is the first time that O-linked oligosaccharides have been detected and described from protein variant of the DMBT1 gene.

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The Biochemical journal, 366, 0264-6021, 511-20, 2002

PMID: 12015815

NaAGP4 is an arabinogalactan protein whose expression is suppressed by wounding and fungal infection in Nicotiana alata.
Gilson P, Gaspar YM, Oxley D, Youl JJ, Bacic A

Arabinogalactan proteins (AGPs) are proteoglycans secreted by plant cells that have been implicated in plant growth and development. Most AGPs cloned to date possess highly labile glycosylphosphatidylinositol (GPI) lipid anchors. These anchors transiently attach AGPs to the plasma membrane before they are released into the cell wall following GPI anchor hydrolysis. We have isolated and partially sequenced the protein core of an AGP purified from styles of Nicotiana alata. The protein sequence data were utilised to clone the AGP's gene, NaAGP4. This AGP shares about 78% sequence identity with the tomato AGP LeAGP-1. RNA gel blot analyses of different plant organs indicate that NaAGP4 is expressed in the same tissues and at similar levels as LeAGP-1. Furthermore, NaAGP4 like LeAGP-1 is rapidly suppressed by tissue wounding and by pathogen infection. We believe NaAGP4 and LeAGP-1 are the first described examples of orthologous AGPs from different plant species. In contrast, another AGP from N. alata, NaAGP1, is comparatively unaffected by wounding and pathogen infection, although this AGP is expressed in similar tissues and at similar levels as NaAGP4.

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Protoplasma, 215, 0033-183X, 128-39, 2001

PMID: 11732052

Structure of the glycosylphosphatidylinositol anchor of an arabinogalactan protein from Pyrus communis suspension-cultured cells.
Oxley D, Bacic A

Arabinogalactan proteins (AGPs) are proteoglycans of higher plants, which are implicated in growth and development. We recently have shown that two AGPs, NaAGP1 (from Nicotiana alata styles) and PcAGP1 (from Pyrus communis cell suspension culture), are modified by the addition of a glycosylphosphatidylinositol (GPI) anchor. However, paradoxically, both AGPs were buffer soluble rather than membrane associated. We now show that pear suspension cultured cells also contain membrane-bound GPI-anchored AGPs. This GPI anchor has the minimal core oligosaccharide structure, D-Manalpha(1-2)-D-Manalpha(1-6)-D-Manalpha(1-4)-D-GlcN -inositol, which is consistent with those found in animals, protozoa, and yeast, but with a partial beta(1-4)-galactosyl substitution of the 6-linked Man residue, and has a phosphoceramide lipid composed primarily of phytosphingosine and tetracosanoic acid. The secreted form of PcAGP1 contains a truncated GPI lacking the phosphoceramide moiety, suggesting that it is released from the membrane by the action of a phospholipase D. The implications of these findings are discussed in relation to the potential mechanisms by which GPI-anchored AGPs may be involved in signal transduction pathways.

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Proceedings of the National Academy of Sciences of the United States of America, 96, 0027-8424, 14246-51, 1999

PMID: 10588691

Arabinogalactan-proteins from Nicotiana alata and Pyrus communis contain glycosylphosphatidylinositol membrane anchors.
Youl JJ, Bacic A, Oxley D

Arabinogalactan-proteins (AGPs) are a class of proteoglycans found in cell secretions and plasma membranes of plants. Attention is currently focused on their structure and their potential role in growth and development. We present evidence that two members of a major class of AGPs, the classical AGPs, AGPNa1 from styles of Nicotiana alata and AGPPc1 from cell suspension cultures of Pyrus communis, undergo C-terminal processing involving glycosylphosphatidylinositol membrane anchors. The evidence is that (i) the transmembrane helix at the C terminus predicted from the cDNA encoding these proteins is not present-the C-terminal amino acid is Asn87 and Ser97 for AGPNa1 and AGPPc1, respectively; (ii) both AGP protein backbones are substituted with ethanolamine at the C-terminal amino acid; and (iii) inositol, glucosamine, and mannose are present in the native AGPs. An examination of the deduced amino acid sequences of other classical AGP protein backbones shows that glycosylphosphatidylinositol-anchors may be a common feature of this class of AGPs.

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Proceedings of the National Academy of Sciences of the United States of America, 95, 0027-8424, 7921-6, 1998

PMID: 9653116

Structure and distribution of N-glycans on the S7-allele stylar self-incompatibility ribonuclease of Nicotiana alata.
Oxley D, Munro SL, Craik DJ, Bacic A

S-RNases are the stylar products of the self-incompatibility (S)-locus in solanaceous plants (including Nicotiana alata), and as such, are involved in the prevention of self-pollination. All cDNA sequences of S-RNase products of functional S-alleles contain potential N-glycosylation sites, with one site being conserved in all cases, suggesting that N-glycosylation is important in self-incompatibility. In this study, we report on the structure and localization of the N-glycans on the S7-allele RNase of N. alata. A total of nine N-glycans, belonging to the high-mannose- and xylosylated hybrid-classes, were identified and characterized by a combination of electrospray-ionization mass-spectrometry (ESI-MS), 1H-NMR spectroscopy, and methylation analyses. The glycosylation pattern of individual glycosylation sites was determined by ESI-MS of the glycans released from isolated chymotryptic glycopeptides. All three N-glycosylation sites showed microheterogeneity and each had a unique complement of N-glycans. The N-glycosylation pattern of the S7-RNase is significantly different to those of the S1- and S2-RNases.

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Journal of biochemistry, 123, 0021-924X, 978-83, 1998

PMID: 9562634

Structural analysis and molecular model of a self-incompatibility RNase from wild tomato.
Parry S, Newbigin E, Craik D, Nakamura KT, Bacic A, Oxley D

Self-incompatibility RNases (S-RNases) are an allelic series of style glycoproteins associated with rejection of self-pollen in solanaceous plants. The nucleotide sequences of S-RNase alleles from several genera have been determined, but the structure of the gene products has only been described for those from Nicotiana alata. We report on the N-glycan structures and the disulfide bonding of the S3-RNase from wild tomato (Lycopersicon peruvianum) and use this and other information to construct a model of this molecule. The S3-RNase has a single N-glycosylation site (Asn-28) to which one of three N-glycans is attached. S3-RNase has seven Cys residues; six are involved in disulfide linkages (Cys-16-Cys-21, Cys-46-Cys-91, and Cys-166-Cys-177), and one has a free thiol group (Cys-150). The disulfide-bonding pattern is consistent with that observed in RNase Rh, a related RNase for which radiographic-crystallographic information is available. A molecular model of the S3-RNase shows that four of the most variable regions of the S-RNases are clustered on one surface of the molecule. This is discussed in the context of recent experiments that set out to determine the regions of the S-RNase important for recognition during the self-incompatibility response.

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Plant physiology, 116, 0032-0889, 463-9, 1998

PMID: 9489006

Identification of active-site histidine residues of a self-incompatibility ribonuclease from a wild tomato.
Parry S, Newbigin E, Currie G, Bacic A, Oxley D

The style component of the self-incompatibility (S) locus of the wild tomato Lycopersicon peruvianum (L.) Mill. is an allelic series of glycoproteins with ribonuclease activity (S-RNases). Treatment of the S3-RNase from L. peruvianum with iodoacetate at pH 6.1 led to a loss of RNase activity. In the presence of a competitive inhibitor, guanosine 3'-monophosphate (3'-GMP), the rate of RNase inactivation by iodoacetate was reduced significantly. Analysis of the tryptic digestion products of the iodoacetate-modified S-RNase by reversed-phase high-performance liquid chromatography and electrospray-ionization mass spectrometry showed that histidine-32 was preferentially modified in the absence of 3'-GMP. Histidine-88 was also modified, but this occurred both in the presence and absence of 3'-GMP, suggesting that this residue is accessible when 3'-GMP is in the active site. Cysteine-150 was modified by iodoacetate in the absence of 3'-GMP and, to a lesser extent, in its presence. The results are discussed with respect to the related fungal RNase T2 family and the mechanism of S-RNase action.

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Plant physiology, 115, 0032-0889, 1421-9, 1997

PMID: 9414554

Disulphide bonding in a stylar self-incompatibility ribonuclease of Nicotiana alata.
Oxley D, Bacic A

Many flowering plants have developed a self-incompatibility mechanism, which is controlled by a single polyallelic locus (the S-locus), to prevent inbreeding. The products of the S-locus in the styles of solanaceous plants are an allelic series of glycoproteins with RNase activity [McClure, B. A., Haring, V., Ebert, P. R., Anderson, M. A., Simpson, R. J., Sakiyama, F. & Clarke, A. E. (1989) Nature 342, 955-957]. These S-RNases show some amino-acid-sequence similarity with two fungal RNases (T2 and Rh), including the presence of two active-site His residues, which suggests a common three-dimensional structure. Disulphide bonding is important in the maintenance of the three-dimensional structure of the fungal RNases [Kurihara, H., Mitsui, Y., Ohgi, K., Irie, M., Mizuno, H. & Nakamura, T. (1992) FEBS Lett. 306, 189-192] and the S-RNases [Tsai, D. S., Lee, H.-S., Post, L. C., Kreiling, K. M. & Kao, T.-H. (1992) Sex. Plant Reprod. 5, 256-263]. We have used the S2-allele RNase of Nicotiana alata, which has nine Cys residues, to establish the pattern of disulphide bonding. The disulphide bonds Cys16-Cys21, Cys45-Cys94, Cys153-Cys182 and Cys165-Cys176 are consistent with the S2-RNase having a similar three-dimensional structure to RNase Rh. A free Cys residue (Cys95) adjacent to Cys45-Cys94 promotes a rapid specific disulphide migration when the protein is exposed to denaturing conditions.

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European journal of biochemistry / FEBS, 242, 0014-2956, 75-80, 1996

PMID: 8954155

Structure of N-glycans on the S3- and S6-allele stylar self-incompatibility ribonucleases of Nicotiana alata.
Oxley D, Munro SL, Craik DJ, Bacic A

Self-incompatibility is a mechanism developed by many plants to prevent inbreeding. The products of the self-incompatibility (S)-locus in the styles of solanaceous plants are a series of glycoproteins with ribonuclease activity. In this study, we report on the N-glycans from the stylar self-incompatibility S3- and S6-ribonucleases of Nicotiana alata, which were enzymically released and fractionated by high-pH anion-exchange HPLC. A total of 14 N-glycans were identified and characterized by a combination of electrospray-ionization mass-spectrometry, 1H-NMR spectros-copy, chemical degradation, and methylation analyses. This patterns of N-glycosylation is much more complex than that previously found on the N.alata S1- and S2-RNases, each of which contained only four N-glycans.

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Glycobiology, 6, 0959-6658, 611-8, 1996

PMID: 8922956

Microheterogeneity of N-glycosylation on a stylar self-incompatibility glycoprotein of Nicotiana alata.
Oxley D, Bacic A

Gametophytic self-incompatibility, a mechanism that prevents inbreeding in some families of flowering plants, is mediated by the products of a single genetic locus, the S-locus. The products of the S-gene in the female sexual tissues of Nicotiana alata are an allelic series of glycoproteins with RNase activity. In this study, we report on the microheterogeneity of N-linked glycosylation at the four potential N-glycosylation sites of the S2-glycoprotein. The S-glycoproteins from N.alata contain from one to five potential N-glycosylation sites based on the consensus sequence Asn-Xaa-Ser/Thr. The S2-glycoprotein contains four potential N-glycosylation sites at Asn27, Asn37, Asn38 and Asn 150, designated sites I, II, IV and V, respectively. Site III is absent from the S2-glycoprotein. Analysis of glycopeptides generated from the S2-glycoprotein by trypsin and chymotrypsin digestions revealed the types of glycans and the degree of microheterogeneity present at each site. Sites I (Asn27) and IV (Asn138) display microheterogeneity, site II (Asn37) contains only a single type of N-glycan, and site V (Asn150) is not glycosylated. The microheterogeneity observed at site I on the S2-glycoprotein is the same as that observed at the only site, site I, on the S1-glycoprotein (Woodward et al., Glycobiology, 2, 241-250, 1992). Since the N-glycosylation consensus sequence at site I is conserved in all S-glycoproteins from other species of self-incompatible solanaceous plants, glycosylation at this site may be important to their function. No other post-translational modifications (e.g. O-glycosylation, phosphorylation) were detected on the S2-glycoprotein.

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Glycobiology, 5, 0959-6658, 517-23, 1995

PMID: 8563138

Structural and serological characterisation of an O-specific polysaccharide from Serratia plymuthica.
Aucken HM, Oxley D, Wilkinson SG

The surface polysaccharides of a strain of Serratia plymuthica were characterised and shown to consist of a linear, acidic galactoglucomannan as well as a major and a minor neutral galactan. Immunoblotting results demonstrated cross-reactions between this strain and others with similar galactans (S. marcescens O16 and O20, Klebsiella O1, and Pasteurella haemolytica T4 and T10).

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FEMS microbiology letters, 111, 0378-1097, 295-300, 1993

PMID: 7691682

Structure of the N-linked oligosaccharides from tridacnin, a lectin found in the haemolymph of the giant clam Hippopus hippopus.
Puanglarp N, Oxley D, Currie GJ, Bacic A, Craik DJ, Yellowlees D

Tridacnin, a glycoprotein lectin, was isolated from the symbiotic marine clam Hippopus hippopus and the structure of its major N-glycan chains determined. Tridacnin contains only N-linked glycans which were quantitatively cleaved by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Following purification by anion-exchange HPLC, the structures of the oligosaccharides were established using a combination of electrospray ionisation mass spectrometry, 1H-NMR spectroscopy and linkage analysis. The N-glycans are primarily of the oligomannose type but, in addition, some contain a novel 6-O-Me group on the terminal mannose residue of the chain. The N-glycan chains had the following structures. [formula: see text]

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European journal of biochemistry / FEBS, 232, 0014-2956, 873-80, 1995

PMID: 7588729

Structural studies of the putative O-specific polysaccharide of Serratia marcescens O9.
Oxley D, Wilkinson SG

A polymeric fraction containing the putative O-antigen has been isolated from the lipopolysaccharide of the reference strain (CDC 4534-60) for serogroup O9 of Serratia marcescens. The major component of the fraction was a polymer with a disaccharide repeating-unit of L-rhamnose (Rha) and 2-acetamido-2-deoxy-D-galactose (GalNAc) with the following structure:----3)D-GalpNAc(beta 1----3)L-Rhap(alpha 1----. Evidence for the presence in the fraction of a similar, minor polymer containing 4-substituted rhamnose residues was provided by the NMR spectra, methylation analysis, and Smith degradation.

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European journal of biochemistry / FEBS, 166, 0014-2956, 421-4, 1987

PMID: 3301342

Structural studies of glucorhamnans isolated from the lipopolysaccharides of reference strains for Serratia marcescens serogroups O4 and O7, and of an O14 strain.
Oxley D, Wilkinson SG

Partially acetylated glucorhamnans have been isolated from the lipopolysaccharides of three strains of Serratia marcescens. The polymer from the reference strain (C.D.C. 864-57) for serogroup O4 has the disaccharide repeating-unit shown below, in which acetylation at position 2 of the rhamnosyl residue is approximately 90% complete. Similar glucorhamnans from the reference strain (C.D.C. 843-57) for serogroup O7 and from a pigmented strain (NM) of serogroup O14 differ only in the configuration of the L-rhamnopyranosyl residue (beta) and the extent of O-acetylation (O7, almost stoichiometric; NM, 80-90%). Glucorhamnans of the second type have been isolated previously from the lipopolysaccharides of other strains of S. marcescens, including the reference strain for serogroup O6 and another pigmented O14 strain (N.C.T.C. 1377). In all cases, the lipopolysaccharide extracts also contained acidic glycans, but the glucorhamnans are believed to constitute the integral side-chains. (Formula: see text).

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Carbohydrate research, 175, 0008-6215, 111-7, 1988

PMID: 3288341

Structure of a neutral polymer isolated from the lipopolysaccharide of Serratia marcescens O5 (C.D.C. 867-57).
Oxley D,Wilkinson SG

Carbohydrate research, 172, 0008-6215, 287-91, 1988

PMID: 3286000

Studies of lipopolysaccharides from two strains (C.D.C. 3607-60 and IP 421) of Serratia marcescens O13: structure of the putative O13 antigen.
Oxley D,Wilkinson SG

Structural studies have been carried out on the putative O-specific polysaccharide of the reference strain (C.D.C. 3607-60) for Serratia marcescens O13. Circumstantial evidence that the O13 antigen is a microcapsular, acidic polymer, rather than an integral part of the lipopolysaccharide, has been obtained. Degradative and spectroscopic studies established that the polymer is based on the repeating unit shown, in which the glucuronic acid residue of the linear pentasaccharide carries the lateral 2-acetamido-2-deoxy-beta-D-glucopyranosyl substituent in only about half of the units. The same polymer, again with non-stoichiometric substitution, is also produced by strain IP 421 (O13:H7). The latter strain also produces a neutral polymer which appears to constitute the side chain of the lipopolysaccharide. This polymer, which has a disaccharide repeating-unit of 2-substituted beta-D-ribofuranosyl and 4-substituted 2-acetamido-2-deoxy-alpha-D-galactopyranosyl residues, has been isolated previously from the lipopolysaccharides of the reference strains for S. marcescens serogroups O12 and O14, and appears to be the antigen known to be shared by these strains. (Formula: see text).

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Carbohydrate research, 172, 0008-6215, 275-86, 1988

PMID: 3285999

Structural studies of an acidic galactomannan from the reference strain for Serratia marcescens serogroup O4.
Oxley D,Wilkinson SG

An acidic, partially acetylated galactomannan has been isolated from the lipopolysaccharide of the reference strain (C.D.C. 864-57) for Serratia marcescens serogroup O4. From the results of methylation analysis, Smith degradations, and n.m.r. spectroscopic studies of the O-deacetylated polymer, it was concluded that the repeating unit has the structure shown, in which the acetal-linked pyruvic acid has the R configuration. The polymer is believed to confer O specificity on the organism, but not to constitute the side chain of the lipopolysaccharide. (formula; see text).

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Carbohydrate research, 179, 0008-6215, 341-8, 1988

PMID: 3061646

Structure of a neutral polymer isolated from the lipopolysaccharide of the reference strain (C.D.C. 4523-60) for Serratia marcescens serogroup O15.
Oxley D,Wilkinson SG

Carbohydrate research, 177, 0008-6215, 285-8, 1988

PMID: 3048660

Structure of the O-specific galactan from the lipopolysaccharide of the reference strain for Serratia marcescens serogroup O24.
Oxley D,Wilkinson SG

The putative O-specific polysaccharide for Serratia marcescens serogroup O24 is a galactan with a branched, trisaccharide repeating-unit of the structure shown. The structure of the backbone is identical to that of the linear galactans isolated from the reference strains for S. marcescens serogroups O16 and O20, presumably accounting for the serological cross-reactions observed. (Formula: see text)

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Carbohydrate research, 195, 0008-6215, 117-22, 1989

PMID: 2699831

Structure of a neutral polymer isolated from the lipopolysaccharide of the reference strain for Serratia marcescens serogroup O18.
Oxley D,Wilkinson SG

A neutral polymer (the putative O antigen) has been isolated from the lipopolysaccharide of the reference strain for Serratia marcescens serogroup 018. From the results of spectroscopic and degradative studies, the repeating unit of the polymer was identified as a linear tetrasaccharide having the structure shown. ----2)-alpha-L-Rhap-(1----2)-alpha-L-Rhap-(1----6)-alpha-D- GlcpNAc-(1----

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Carbohydrate research, 195, 0008-6215, 111-5, 1989

PMID: 2699830

Structures of neutral glycans isolated from the lipopolysaccharides of reference strains for Serratia marcescens serogroups O16 and O20.
Oxley D,Wilkinson SG

Neutral polymers have been isolated from the lipopolysaccharides of the reference strains for Serratia marcescens O16 and O20, serogroups which exhibit significant cross-reactivity. Both organisms produce a galactan with the disaccharide repeating-unit shown, and which apparently accounts for the serological observations. The same galactan has also been reported as the O4-specific polysaccharide of Pasteurella haemolytica. In S. marcescens O16, the galactan is apparently accompanied by a polymer of 2-substituted beta-D-ribofuranosyl residues.

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Carbohydrate research, 193, 0008-6215, 241-8, 1989

PMID: 2692814

Structural studies of an acidic galactoglucomannan from the O15 reference strain (C.D.C. 4523-60) of Serratia marcescens.
Oxley D,Wilkinson SG

Both neutral and acidic polymers have been isolated from the lipopolysaccharide extract of the reference strain (C.D.C. 4523-60) for Serratia marcescens serogroup O15. By means of n.m.r. spectroscopy, methylation analysis, and studies of degradation products, the acidic polysaccharide was shown to have a branched pentasaccharide repeating-unit with the following structure. (Formula: see text)

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Carbohydrate research, 186, 0008-6215, 295-300, 1989

PMID: 2660988