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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both cooked red meat intake and chronic inflammation/infection are thought to play a role in the etiology of colon cancer. The heterocyclic amine 2-amino-3-methylimidazo[4,5-f ]quinoline (IQ) is formed during cooking of red meat and may be involved in initiation of colon cancer. Reactive nitrogen oxygen species (RNOS), components of the inflammatory response, contribute to the deleterious effects attributed to inflammation on normal tissues. This study assessed the possible chemical transformation of IQ by RNOS. RNOS were generated by various conditions to react with (14)C-IQ, and samples were evaluated by HPLC. Myeloperoxidase (MPO)-catalyzed reaction was dependent upon both H(2)O(2) and NO(2)(-). This reaction produced an azo-IQ dimer and IQ dimer along with two nitrated IQ products identified by ESI/MS. 2-Nitro-IQ was not detected. Product formation was inhibited by 2 mM cyanide. Reduction in nitrated products observed with 100 mM chloride was not altered with 0.5 mM taurine. Nitrated products were also produced by other conditions, ONOO(-) and NO(2)(-) + HOCl, which generate nitrogen dioxide radical. In contrast, conditions which generate N(2)O(3), such as diethylamine NONOate, produced only small amounts of nitrated products with the major product identified by MS and NMR as N-nitroso-IQ. MPO activation of IQ to bind DNA was dependent upon both H(2)O(2) and NO(2)(-). RNOS generated by ONOO(-) and DEA NONOate also activated IQ DNA binding. The nitrated IQ products were not activated by MPO to bind DNA. In contrast, N-nitroso-IQ was activated to bind DNA by MPO +/- NO(2)(-). HOCl activated N-nitroso-IQ, but not IQ. RAW cells produced N-nitroso-IQ and increased amounts of NO(2)(-)/NO(3)(-), when incubated with 0.1 mM IQ and stimulated with lipopolysaccharide and interferon gamma. Results demonstrate chemical transformation and activation of IQ by RNOS and activation of its N-nitroso product by biological oxidants, events which may contribute to initiation of colon cancer.
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PMID:Nitrosation and nitration of 2-amino-3-methylimidazo[4,5-f]quinoline by reactive nitrogen oxygen species. 1218 90

1Alpha,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been shown to modulate the production of various cytokines or the expression of certain differentiation markers in human T cells or monocytes. Its effects on neutrophils, however, are poorly understood. In this paper, we show several lines of evidence indicating that neutrophils express functional vitamin D receptors (VDR). Sort-purified neutrophils from human peripheral blood expressed VDR mRNA at a level comparable to that of monocytes. As reported to occur in monocytes, protein expression of CD14 on the cell surface of neutrophils was augmented when the cells were incubated with 1,25(OH)2D3. To investigate the physiological roles for VDR in neutrophils, we investigated possible modulating effects of 1,25(OH)2D3 on the expression of several genes in lipopolysaccharide-stimulated neutrophils by using differential display analysis. Of the genes we identified, trappin-2/elafin/SKALP, which was originally reported to be an inhibitor of elastase, was induced in neutrophils by lipopolysaccharide, but was suppressed significantly in the presence of 1,25(OH)2D3. Under the same conditions, interleukin-1beta expression was also inhibited. These findings suggest that 1,25(OH)2D3 has a potential to affect the inflammatory process by modulating the expression of neutrophil genes.
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PMID:Human neutrophils express messenger RNA of vitamin D receptor and respond to 1alpha,25-dihydroxyvitamin D3. 1237 32

Structural elucidation of the lipopolysaccharide (LPS) from three nontypeable Haemophilus influenzae clinical isolates, 1209, 1207 and 1233 was achieved using NMR spectroscopy and ESI-MS on O-deacylated LPS and core oligosaccharide (OS) material as well as ESI-MS(n) on permethylated dephosphorylated OS. It was found that the organisms expressed a tremendous heterogeneous glycoform mixture resulting from the variable length of the OS chains attached to the common structural element of H. influenzae, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-L-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-Lipid A. Notably, the O-6 position of the beta-D-Glcp residue could either be occupied by PCho or L-glycero-D-manno-heptose (L,D-Hep), which is a location for L,D-Hep that has not been seen previously in H. influenzae LPS. The outer-core L,D-Hep residue was further chain elongated at the O-6 position by the structural element beta-D-GalpNAc-(1-->3)-alpha-D-Galp-(1-->4)-beta-D-Galp, or sequentially truncated versions thereof. The distal heptose residue in the inner-core was found to be chain elongated at O-2 by the globotetraose unit, beta-D-GalpNAc-(1-->3)-alpha-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-beta-D-Glcp, or sequentially truncated versions thereof. Investigation of LPS from an lpsA mutant of isolate 1233 and a lic1 mutant of isolate 1209 was also performed, which aside from confirming the functions of the gene products, simplified elucidation of the OS extending from the proximal heptose (the lpsA mutant), and showed that the organism exclusively expresses LPS glycoforms comprising the outer-core l,d-Hep residue when PCho is not expressed (the lic1 mutant).
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PMID:Structural diversity in lipopolysaccharide expression in nontypeable Haemophilus influenzae. Identification of L-glycerol-D-manno-heptose in the outer-core region in three clinical isolates. 1258 Dec 1

Structural analysis of the lipopolysaccharide (LPS) from nontypeable Haemophilus influenzae strain 981 has been achieved using NMR spectroscopy and ESI-MS on O-deacylated LPS and core oligosaccharide (OS) material as well as by ESI-MSn on permethylated dephosphorylated OS. A heterogeneous glycoform population was identified, resulting from the variable length of the OS branches attached to the glucose residue in the common structural element of H. influenzae LPS, l-alpha-d-Hepp-(1-->2)-[PEtn-->6]-l-alpha-d-Hepp-(1-->3)-[beta-d-Glcxp-(1-->4)]-l-alpha-d-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-Lipid A. Notably, the O-6 position of the beta-d-Glcp residue was either substituted by PCho or the disaccharide branch beta-d-Galp-(1-->4)-d-alpha-d-Hepp, while the O-4 position was substituted by the globotetraose unit, beta-d-GalpNAc-(1-->3)-alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glcp, or sequentially truncated versions thereof. This is the first time a branching sugar residue has been reported in the outer-core region of H. influenzae LPS. Additionally, a PEtn group was identified at O-3 of the distal heptose residue in the inner-core.
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PMID:Structural characterization of a novel branching pattern in the lipopolysaccharide from nontypeable Haemophilus influenzae. 1284 31

Structural elucidation of the lipopolysaccharide (LPS) from three serotype f Haemophilus influenzae clinical isolates RM6255, RM7290 and RM6252 has been achieved using NMR spectroscopy techniques and ESI-MS on O-deacylated LPS and core oligosaccharide material (OS) as well as ESI-MSn on permethylated dephosphorylated OS. This is the first study to report structural details on LPS from serotype f strains. We found that the LPSs of all strains were highly heterogeneous mixtures of glycoforms expressing the common H. influenzae structural element l-alpha-d-Hepp-(1-->2)-[PEtn-->6]-l-alpha-d-Hepp-(1-->3)-[beta-d-Glcp-(1-->4)]-l-alpha-d-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdo-(2-->6)-lipid A with variable length of OS chains linked to each of the heptoses. The terminal heptose (HepIII) in RM6255 is substituted at the O-3 position by a beta-d-Glcp residue whereas HepIII in strains RM7290 and RM6252 is substituted at O-2 by the globoside unit (alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glc) or truncated versions thereof. The central heptose (HepII) is substituted by an alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glcp-(1-->4)-alpha-d-Glcp unit in RM7290 and RM6252 or truncated versions thereof. Strain RM6255 does not express galactose in its LPS and only shows a cellobiose unit elongating from HepII (beta-d-Glcp-(1-->4)-alpha-d-Glcp). ESI-MSn on dephosphorylated and permethylated OS provided information on the existence of additional minor isomeric glycoforms.
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PMID:Structural analysis of lipopolysaccharides from Haemophilus influenzae serotype f. Structural diversity observed in three strains. 1286 90

A phosphorylated core-lipid A backbone oligosaccharide that carries a disaccharide remainder of the first O-antigen repeating unit was derived by strong alkaline degradation following mild hydrazinolysis of the lipopolysaccharide of Pseudomonas aeruginosa immunotype 4 (serogroup O-1). The structure of the oligosaccharide was determined using ESI MS and NMR spectroscopy and it was demonstrated that 2-acetamido-2,6-dideoxy-D-glucose is the first monosaccharide of the O-polysaccharide that is linked to the LPS core. These data define the structure of the biological repeating unit of the O-antigen.
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PMID:Structure of the biological repeating unit of the O-antigen of Pseudomonas aeruginosa immunotype 4 containing both 2-acetamido-2,6-dideoxy-D-glucose and 2-acetamido-2,6-dideoxy-D-galactose. 1289 48

The lipopolysaccharide of Pseudomonas aeruginosa O-12 was studied by strong alkaline and mild acid degradations and dephosphorylation followed by fractionation of the products by GPC and high-performance anion-exchange chromatography and analyses by ESI FT-MS and NMR spectroscopy. The structures of the lipopolysaccharide core and the O-polysaccharide repeating unit were elucidated and the site and the configuration of the linkage between the O-polysaccharide and the core established. The core was found to be randomly O-acetylated, most O-acetyl groups being located on the terminal rhamnose residue of the outer core region.
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PMID:Structure of the lipopolysaccharide of Pseudomonas aeruginosa O-12 with a randomly O-acetylated core region. 1293 74

Haemophilus influenzae is an important cause of human disease, and its lipopolysaccharide (LPS) is known to be a major virulence factor. H. influenzae produces short-chain LPS of which the heterogeneity is often visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using silver staining for detection. Individual bands have not previously been recovered by this method in quantities sufficient for mass spectrometry. In an attempt toward the development of sensitive mass spectrometrical strategies to be used in structural studies of H. influenzae LPS and LPS from other bacteria, we have applied here our previously described slab-PAGE-based micropurification method to obtain unmodified LPS fractions of high purity (>95%) from a crude LPS preparation of H. influenzae strain Rd. Two LPS-fractions were obtained which, after a procedure including mild acid hydrolysis, dephosphorylation, and permethylation of the resulting oligosaccharides, were subjected to tandem electrospray ionization mass spectrometry (ESI-MS/MS). The quantities of micropurified LPS fractions-the recovery of LPS in terms of total mass was 30%-were found sufficient to allow the characterization of LPS glycoforms. The ESI-MS spectra of the individual bands showed reduced heterogeneity. Furthermore, the integrity of the micropurified LPS was confirmed. The spectra-displayed molecular ions showed improved intensity, increased respective signal-to-noise ratios demonstrating the sensitivity of analysis. Consequently, both the direct determination of the molecular masses of the gel-separated LPS glycoforms and sequence analyses using ESI-MS/MS were possible.
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PMID:Linking mass spectrometry and slab-polyacrylamide gel electrophoresis by passive elution of lipopolysaccharides from reverse-stained gels: analysis of gel-purified lipopolysaccharides from Haemophilus influenzae strain Rd. 1467 72

The lipopolysaccharide (LPS) of the opportunistic human pathogen Pseudomonas aeruginosa immunotype 5 was delipidated by mild acid hydrolysis, and the products were separated by high-performance anion-exchange chromatography and analyzed by ESI MS and NMR spectroscopy. LPS species of three types were found, including those with an unsubstituted core and the core substituted with one O-polysaccharide repeating unit or with an O-polysaccharide of a variable number of repeating units. The core region is highly phosphorylated, the major species containing two monophosphate groups and one ethanolamine diphosphate group. Based on these and published data on the O-polysaccharide structure, the full structure of the LPS of P. aeruginosa immunotype 5 was established.
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PMID:Full structure of the lipopolysaccharide of Pseudomonas aeruginosa immunotype 5. 1500 Jun 83

Nontypeable Haemophilus influenzae (NTHi) is a common commensal of the human upper respiratory tract and is associated with otitis media in children. The structures of the oligosaccharide portions of NTHi lipopolysaccharide (LPS) from several otitis media isolates are now well characterized but it is not known whether there are structural differences in LPS from colonizing, nondisease associated strains. Structural analysis of LPS from nondisease associated NTHi strains 11 and 16 has been achieved by the application of high-field NMR techniques, ESI-MS, ESI-MSn, capillary electrophoresis coupled to ESI-MS, composition and linkage analyses on O-deacylated LPS and core oligosaccharide material. This is the first study to report structural details on LPS from strains taken from the nasopharynx from healthy individuals. Both strains express identical structures and contain the common element of H. influenzae LPS, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-L-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-lipid A, in which each heptose is elongated by a single hexose residue with no further oligosaccharide extensions. In the major Hex3 glycoform, the terminal Hepp residue (HepIII) is substituted at the O-2 position by a beta-D-Galp residue and the central Hepp residue (HepII) is substituted at O-3 by a alpha-D-Glcp residue. Notably, the strains express two phosphocholine (PCho) substituents, one at the O-6 position of alpha-D-Glcp and the other at the O-6 position of beta-D-Galp. Major acetylation sites were identified at O-4 of Gal and O-3 of HepIII. Additionally, both strains express glycine, and strain 11 also expresses detectable amounts of N-acetylneuraminic acid.
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PMID:Characterization of novel structural features in the lipopolysaccharide of nondisease associated nontypeable Haemophilus influenzae. 1500 6


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