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PubMed1989

Structure of the lipopolysaccharide antigenic O-chain produced by Actinobacillus pleuropneumoniae serotype 4 (ATCC 33 378).

The structure of the antigenic O-polysaccharide part of the S-type lipopolysaccharide produced by Actinobacillus pleuropneumoniae serotype 4 has been determined by periodate oxidation, methylation, partial hydrolysis, and 1H- and 13C-n.m.r. spectroscopy. The O-polysaccharide structure has a branched-tetrasaccharide repeating unit, (----3)-beta-D-Galp-(1----4)-[beta-D-Glcp-(1----3)]-beta-D-GalpNAc- (1----4)-alpha-L-Rhap-(1-)n. The structure resembles that of the lipopolysaccharide O-chain of A. pleuropneumoniae serotype 7, and their common epitopes may account for the apparent serological cross-reactivity observed between the two serotypes when incompletely adsorbed, anticapsular-typing sera are used.

Actinobacillus↗

PubMed1991

Structure of an acidic glycan present in the lipopolysaccharide extract from the reference strain for Serratia marcescens serogroup O18.

The lipopolysaccharide extract from the cell wall of the reference strain for Serratia marcescens serogroup O18 contained, in addition to a neutral glycan characterised previously, an acidic glycan. Acidity was contributed both by D-glucuronic acid and by 4-O-[(R)-1-carboxyethyl]-D-glucose (4-O-Lac-D-Glc). By using n.m.r. spectroscopy, methylation analysis, and chemical degradations, the repeating unit of the acidic glycan was identified as a branched hexasaccharide having the structure shown; an O-acetyl group also present was not located. The glycan is believed to define the O18 serogroup, but is probably not an integral component of the lipopolysaccharide. [formula: see text].

Carbohydrate Conformation↗

PubMed1992

The structure of the sialic acid-containing Escherichia coli O104 O-specific polysaccharide and its linkage to the core region in lipopolysaccharide.

Mild acid hydrolysis of Escherichia coli O104 lipopolysaccharide released an O-specific polysaccharide, a tetrasaccharide repeating unit, the corresponding dimer, and a disaccharide fragment of the repeating unit. Complete and incomplete cores, and oligosaccharides comprising fragments of the repeating unit and the core region, were also obtained. On the basis of sugar and methylation analysis, FAB-mass spectrometry and NMR spectroscopy of the hydrolysis products, the repeating unit of the O-specific polysaccharide was shown to be the tetrasaccharide:-->4)-alpha-D-Galp-(1-->4)-alpha-Neup5,7,9Ac3++ +-(2-->3)-beta-D- Galp-(1-->3)-beta-D-GalpNAc (1-->. The linkage between the O-specific polysaccharide chain and the core region, which appeared to be of the R2 type, was established. These results indicate that N-acetylneuraminic acid, located in the O-specific polysaccharide, is an inherent lipopolysaccharide component.

Carbohydrate Conformation↗

PubMed1993

Structural studies of the saccharide part of the cell envelope lipopolysaccharide from Haemophilus influenzae strain AH1-3 (lic3+).

The structure of the saccharide part of the lipopolysaccharide from Haemophilus influenzae strain AH1-3 (lic3+) has been investigated. The saccharide was obtained from the lipopolysaccharide by mild acid hydrolysis followed by high-performance anion-exchange chromatography, and isolated fractions were studied by methylation analysis, NMR spectroscopy, and FAB mass spectrometry. The major saccharide is a heptasaccharide with the following structure, [formula: see text] in which Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid and PEA is 2-aminoethyl phosphate. Hep is identified as L-glycero-D-manno-heptose. The absolute configuration of the phosphorylated heptose is tentative only.

Carbohydrate Sequence↗

PubMed1994

The structure of the O-antigenic chain of the lipopolysaccharide of Rhizobium trifolii 4s.

The structure of the O-antigen chain of the lipopolysaccharide (LPS) of Rhizobium trifolii 4s has been determined by a combination of chemical and spectroscopic methods. The glycosyl components were found to be L-rhamnose, N-acetyl-D-glucosamine, and N-acetyl-D-mannosamine in 3:1:1 molar proportion, as determined by gas chromatography and gas chromatography-mass spectrometry of alditol acetate and persilylated (R)-2-hydroxybutyl glycoside derivatives. The linkage positions and configurations of the glycosyl residues were obtained by 1D and 2D NMR spectroscopy. The polymer has a pentasaccharide repeating-unit containing rhammose and N-acetylglucosamine in the main chain and N-acetylmannosamine as the sole-side chain component. This latter residue is linked to a main-chain rhamnose residue. This result was suggested by NMR spectroscopy and confirmed by periodate oxidation. The sequence was deduced by 1D and 2D NMR NOE experiments and by partial hydrolysis studies. The repeating unit of the polysaccharide is shown. This constitutes the first complete structure of an O-antigenic chain of the lipopolysaccharide of any strain of Rhizobium trifolii.

Acetylglucosamine↗

PubMed1994

Structure of the O-specific side chain of the lipopolysaccharide from Escherichia coli O126.

The polysaccharide isolated from Escherichia coli O126 lipopolysaccharide contains D-galactose, D-mannose, L-fucose, and 2-acetamido-2-deoxy-D-glucose in the molar ratios 1:1:1:1. The structure of the O-antigen of the lipopolysaccharide from E. coli O126 was established by compositional analysis, partial degradation, methylation analysis, and nuclear magnetic resonance spectroscopy. These studies revealed that the O-antigen is branched and built up of tetrasaccharide repeating units having the following structure: [formula: see text]

Carbohydrate Conformation↗

PubMed1996

Structural studies of the Vibrio salmonicida lipopolysaccharide.

The oligosaccharide part of the Vibrio salmonicida (strain NCMB 2262) lipopolysaccharide was isolated by mild acid hydrolysis followed by gel-permeation chromatography. The structure was established mainly by methylation analysis, mass spectrometry, and NMR spectroscopy. It is concluded that the oligosaccharide has the following structure, in which L-alpha-D-Hep p is L-glycero-alpha-D-manno-heptopyranose, D-alpha-D-Hepp is D-glycero-alpha-D-manno-heptopyranose, alpha-D-Fuc p4N is 4-amino-4,6-dideoxy-alpha-D-galactopyranose, alpha-NonA is 5-acetamidino-7-acetamido-3,5,7, 9-tetradeoxy-L-glycero-alpha-D-galacto-nonulosonic acid, BA is (R)-3-hydroxybutanoyl, and PEA is phosphoethanolamine. The substitution pattern of the branching heptosyl residue was deduced from 1H NMR chemical shifts and conformations of the branching region, obtained by molecular modelling. The absolute configuration for NonA was determined by NMR spectroscopy from NOE correlations to the neighbouring sugar and 13C NMR chemical shift data. It could also be shown that assignments of nonulosonic acids with the D-glycero-L-galacto configuration, reported by previous investigators, are erroneous and should be changed to L-glycero-D-galacto. The oligosaccharide is assumed to be linked to the 5-position of a Kdo residue, phosphorylated in the 4-position as observed for other lipopolysaccharides from Vibrionaceae. [formula: see text]

Carbohydrate Conformation↗

PubMed1987

Increased activation of antigen-primed or memory B cells by bacterial lipopolysaccharide.

Treatment with bacterial lipopolysaccharide elicits the appearance of greater numbers of background antigen-specific plaque-forming cells (PFC) in the spleens of mice previously exposed or primed to subimmunogenic amounts of various non-cross-reacting antigens so as to generate detectable immunological memory. These findings suggest that treatment with lipopolysaccharide results in the activation of increased numbers of antigen-primed or memory B cells in mice previously exposed to antigen.

Animals↗

PubMed1989

Human endothelial cell response to lipopolysaccharide, interleukin-1, and tumor necrosis factor is regulated by protein synthesis.

In this study we assessed the viability of cultured human umbilical vein endothelial cells (HUVE) treated with bacterial lipopolysaccharide (LPS), recombinant human interleukin-1 (rhIL-1), or recombinant human tumor necrosis factor-alpha (rhTNF-alpha) during inhibition of RNA or protein synthesis. Cytotoxicity was determined by 51Cr activity retained in labeled HUVE monolayers after exposure to LPS, rhIL-1 or rhTNF-alpha, and cycloheximide (Cx) or actinomycin D (Act D). Lipopolysaccharide (150 ng/ml), rhIL-1 (100 pg/ml), or rhTNF-alpha (20 ng/ml) alone was not toxic to HUVE in an 18-hr incubation. Cycloheximide alone (1 microgram/ml for 18 hr) or Act D alone (1 microgram/ml for 6 hr) was also not toxic to HUVE. However, coincubation of HUVE with Cx and LPS (150 ng/ml), rhIL-1 (10 pg/ml), or rhTNF-alpha (20 ng/ml) produced significant cytotoxicity at 18 hr (70 +/- 4% for LPS, 75 +/- 5% for rhIL-1, and 52 +/- 5% for rhTNF-alpha; mean +/- SEM of 18, 16, and 19 separate experiments, respectively). Similarly, coincubation of HUVE with Act D and LPS, rhIL-1, or rhTNF-alpha resulted in 82 +/- 5%, 85 +/- 3%, and 67 +/- 4% cytotoxicity, respectively, at 6 hr (mean +/- SEM of 5 separate experiments for LPS, and 7 separate experiments each for rhIL-1 and rhTNF-alpha). At the highest concentrations of LPS, rhIL-1, or rhTNF-alpha, cytotoxicity during coincubation with Cx or Act D was detected as early as 2 hr and was near maximal by 6 hr. In contrast to LPS, rhIL-1, or rhTNF-alpha, recombinant human interferon-gamma (up to 100 U/ml), or human alpha-thrombin (up to 10 U/ml), produced no cytotoxicity in the presence of Cx. Recombinant human lymphotoxin (up to 50 ng/ml) had a detectable cytotoxic effect in the presence of Cx although it was significantly less than that seen with rhTNF-alpha. Furthermore, coincubation of human fibroblasts and human smooth muscle cells with Cx and LPS, rhIL-1, or rhTNF-alpha produced no cytotoxicity. We conclude that under these culture conditions, LPS, rhIL-1, or rhTNF-alpha produces a lethal injury to HUVE when de novo RNA or protein synthesis is inhibited. These results suggest that LPS, rhIL-1, and rhTNF-alpha may act via a common pathway in endothelial cells and that protein synthesis is important in regulating the response to these stimuli.

Cells, Cultured↗

PubMed1992

Endothelium-accelerated hyporesponsiveness of norepinephrine-elicited contraction of rat aorta in the presence of bacterial lipopolysaccharide.

The role of the endothelium in the hyporesponsiveness of alpha-adrenoceptor-mediated contractions of the rat aorta was investigated. The norepinephrine-induced maximal contraction was diminished after repeated addition of the agonist. The hyporesponsiveness of the maximal contraction was endothelium dependent, being prevented by NG-monomethyl-L-arginine (0.5 mM), L-argininosuccinic acid (0.5 mM), puromycin (IC50 = 100 microM), actinomycin D (IC50 = 80 nM) but not by indomethacin, which suggests that nitric oxide (NO) synthase is induced. The sensitivity of the rings to NO-induced relaxation remained unchanged. The above-mentioned hyporesponsiveness of norepinephrine-induced maximal contractions of aorta rings was also observed after a 5-h incubation without norepinephrine. The agonist-independent hyporesponsiveness was also prevented by NG-monomethyl-L-arginine, puromycin and actinomycin D, which suggests that NO synthase is induced. Moreover, the norepinephrine-independent hyporesponsiveness was prevented by polymyxin B (10 micrograms/ml), which suggests that bacterial lipopolysaccharide (LPS) might be involved. The concentration of contaminating LPS was 89 +/- 11 ng/ml. When the concentration of contaminating LPS was reduced to 40-70 pg/ml, the hyporesponsiveness of the maximal contraction did not occur after repeated addition of norepinephrine or alter a 5-h incubation without the agonist. An addition of 30 or 100 ng/ml of E. coli lipopolysaccharide to the organ bath reproduced the hyporesponsiveness of the maximal contraction. After a 5-h incubation of aortic rings with 30 ng/ml LPS, only the endothelium-intact ring showed a reduced contraction. However, a 24-h incubation reduced the contraction even in the absence of endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗

PubMed1993

Cationic amino acids inhibit the effects of L-arginine in rat aorta exposed to lipopolysaccharide.

The effects of L-arginine (10(-7) to 10(-2) M), L-lysine and L-ornithine were examined in endothelium-denuded rat aortic rings preincubated 4 h with lipopolysaccharide (10 micrograms/ml) and contracted with noradrenaline (3 microM). L-Lysine (10 mM) and L-ornithine (10-30 mM) slightly increased contraction and caused a rightward shift in concentration-relaxation curves in response to L-arginine. These cationic amino acids may compete with L-arginine for the lipopolysaccharide-induced NO-synthase or the amino acid transporter, or both.

Amino Acids↗

PubMed1993

N-Acetylserotonin prevents the hypotension induced by bacterial lipopolysaccharides in the rat.

Nitric oxide is produced by the NO synthase, which catalyses the conversion of arginine to citrulline and NO using tetrahydrobiopterin as an essential cofactor. N-Acetylserotonin, an inhibitor of the tetrahydrobiopterin biosynthesis, given 30 min before bacterial lipopolysaccharide to anesthetized rats, inhibited both the decrease in blood pressure and the increase in nitrite plasma levels induced by lipopolysaccharide. Thus, during endotoxemia the availability of tetrahydrobiopterin appears to be essential for the activity of NO synthase.

Amino Acid Oxidoreductases↗

PubMed1994

Selective inhibition of sympathetic nerve-mediated contraction by L-arginine in lipopolysaccharide-treated tail artery of rats.

The effects of L-arginine on the adrenergic responses to either electrical transmural stimulation or phenylephrine were studied in isolated endothelium-denuded strips of rat tail arteries treated with lipopolysaccharide for 6 h in vitro. L-arginine did not relax the strips precontracted by phenylephrine. However, the adrenergic contractions induced by electrical transmural stimulation were significantly inhibited by the addition of L-arginine. This inhibitory effect was reversed by NG-nitro-L-arginine (a nitric oxide synthase inhibitor) or methylene blue (a soluble guanylate cyclase inhibitor) but was not affected by hemoglobin (a scavenger of nitric oxide). These results indicate that the adrenergic neurogenic contractions may be directly modulated by nitric oxide derived from the sympathetic nerves and/or neighboring cells in the lipopolysaccharide-treated rat tail arteries, and the nitric oxide production may be associated with the reduction of sympathetic tone in sepsis.

Amino Acid Oxidoreductases↗

PubMed1995

Increase in serum NG-hydroxy-L-arginine in rats treated with bacterial lipopolysaccharide.

Aortic rings isolated from rats 4 h after an injection i.p. of 30 mg/kg Escherichia coli lipopolysaccharide showed a marked hyporeactivity to noradrenaline. This effect was paralleled by an increase in the level of nitrite/nitrate in the serum of lipopolysaccharide-treated rats, indicative of an enhanced nitric oxide (NO) synthase activity. Most important, however, the serum concentration of the NO synthase intermediate, NG-hydroxy-L-arginine, was also markedly elevated from 3.7 to 15.8 microM. Circulating NG-hydroxy-L-arginine may thus represent a sensitive and specific marker of NO synthase activity in vivo.

Amino Acid Oxidoreductases↗

PubMed1995

Lipopolysaccharide determination by reversed-phase high-performance liquid chromatography after fluorescence labeling.

A sensitive method for the quantitative determination of lipid A, the covalently bound hydrophobic component of lipopolysaccharides (endotoxins), has been developed. The determination of lipid A was based on the quantitative measurement of beta-hydroxymyristic acid and beta-hydroxylauric acid by reversed-phase HPLC. beta-Hydroxy acids were liberated from ester and amide linkages in endotoxins by acid catalyzed methanolysis. The resulting methyl esters were derivatized with 9-anthracene-carboxyl chloride, 9-fluorene-carboxyl chloride and 4-(1-pyrenyl)butyric acid chloride and quantified with a fluorescence detector. The effectiveness of the three derivatizing agents was compared. As internal standards-beta-hydroxytridecanoic acid [beta-OH(13:0)] and beta-hydroxypentadecanoic acid [beta-OH(15:0)] ethyl esters were used. The limits of detection of beta-hydroxymyristic acid were 0.5 pg for the 9-anthroyl and 2 pg for the fluorenoyl and 4-(1-pyrenyl)butyroyl ester per sample (signal-to-noise ratio of 3). The detection limits of lipopolysaccharide from a smooth strain (Escherichia coli 0111:B4) was 20 pg, while that from two rough strains (E. coli Nissle 1917 and Salmonella typhimurium SL 1181) was 5 pg per sample after methanolysis and derivatization with 9-anthroyl chloride.

Chromatography, High Pressure Liquid↗

PubMed1978

Effect of thymosin and lipopolysaccharide on murine lymphocyte cyclic AMP.

The effects of thymosin and lipopolysaccharide (LPS) on cyclic AMP levels in lymphocytes were evaluated using three independent assays which included adenine prelabeling, protein kinase binding, and radioimmunoassay. All three assays proved to be both sensitive and accurate in assessing relative changes in lymphocytes after incubation in vitro with various agents. The assays confirmed that basal and stimulated levels of cyclic AMP depended on the origin of the lymphocyte population. Each of the three techniques demonstrated that pyrogen-free bovine thymosin fraction 5 did not elevate thymocyte cAMP levels. In contrast, it was found that lipopolysaccharide (lps) significantly elevated cAMP levels in both spleen and thymus lymphocytes. These studies indicate that assays for measuring the activity of thymic extracts in which the intracellular levels of cyclic nucleotides are a criterion for activity are only valid if the preparations are not contaminated with endotoxins.

Animals↗

PubMed1982

Synthesis of immunogenic oligosaccharide-protein conjugates from the lipopolysaccharide of Neisseria gonorrhoeae P9.

Oligosaccharide was isolated from the lipopolysaccharide of Neisseria gonorrhoeae P9 following partial acid hydrolysis. The exposed terminal keto-deoxyoctonic acid group of the oligosaccharide was convert into the reactive phenylisothiocyanato derivative by reaction with 2-(4-aminophenyl)-ethylamine followed by reduction with sodium cyanoborohydride and treatment with thiophosgene. This intermediate was used to prepare an oligosaccharide-protein conjugate with either bovine serum albumin or purified gonococcal pili. Immunisation of rabbits with protein conjugates produced antibodies reactive with both pure protein and intact lipopolysaccharide.

Animals↗

PubMed1986

Characterization and diagnostic application of a lipopolysaccharide core oligosaccharide-protein conjugate.

Shigella sonnei phase II core oligosaccharide (OSPhII) was linked covalently with protein (bovine serum albumin or tetanus toxoid) to obtain a conjugate (OSPhII-protein) of good immunogenicity in rabbits. Anti-OSPhII-protein conjugate sera contained high levels of immunoglobulin G antibodies against the complete core region of Sh. sonnei lipopolysaccharide. The antigenic relationships between lipopolysaccharides of R1, R3 and R4 core types using anti-OSPhII-protein sera were studied. These antisera may be used for the rapid determination of core types in unknown enterobacterial strains.

Animals↗