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PubMed1986

Structural studies on O-specific polysaccharides of lipopolysaccharides from Yersinia enterocolitica serovars O:5 and O:5,27.

Lipopolysaccharides of Yersinia enterocolitica serovars O:5 and O:5,27 were shown to have a similar sugar composition, consisting of L-rhamnose, D-glucose, D-galactose, D- and L-glycero-D-manno-heptose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, 3-deoxy-D-manno-octulosonate and D-threo-pent-2-ulose (D-xylulose). Partial hydrolysis of lipopolysaccharides with acetic acid produced rhamnans with the following repeating unit: ----3)-L-Rha rho(alpha 1----3)-L-Rha rho(alpha 1----3)-L-Rha rho(beta 1----. 13C-NMR and methylation studies of the lipopolysaccharides gave the following structure for the repeating unit of the two O-specific polysaccharides: ----3)-L-Rha rho(alpha 1----3)-L-Rha rho(alpha 1----3)-L-Rha rho(beta 1----. (formula; see text)

Antigens, Bacterial↗

PubMed1986

The structure of the heptose-3-deoxy-D-mannooctulosonic-acid region in a mutant form of Aeromonas salmonicida lipopolysaccharide.

Lipopolysaccharide was isolated from a phage-selected mutant of a wild strain of Aeromonas salmonicida by the aqueous phenol method. The lipopolysaccharide consisted of the R form, containing per mole, three moles of L-glycero-D-manno-heptopyranose, one mole of 3-deoxy-D-manno-2-octulosonic acid (dOclA) and lipid A. The dOclA was not fully assayable by the thiobarbituric acid methods usually used, but its degradation product was detected, after Smith degradation of the lipopolysaccharide, either as free 3-deoxy-2-heptulosonic acid (after hydrolysis) or substituted by a mannopyranosyl residue derived from heptose. Mass spectrometry indicated that the dOclA existed in the furanose form and was substituted by the heptose trisaccharide through position six. Methylation analysis, chemical degradation, chromium trioxide oxidation and nuclear magnetic resonance spectroscopy were used to identify the structure of the core oligosaccharide as: L alpha DHepp(1----2)L alpha DHepp(1----3)L alpha DHepp(1----6)dOclAf(2----.

Acetylation↗

PubMed1989

Characterization of the lipid A component of genuine smooth-form lipopolysaccharide.

The smooth-form lipopolysaccharide of Salmonella abortus equi had earlier been separated into three distinct fractions, a long-chain fraction with an O chain containing 20-50 repeating units, a short-chain fraction consisting of an R lipopolysaccharide and another with 1-6 repeating units, and an R fraction identical to the lipopolysaccharide synthesized by Ra.b-mutant bacteria [Galanos et al. (1988) J. Chromatogr. 440, 397-404]. In this paper, the corresponding lipid A from each fraction was prepared by a newly elaborated procedure based on hydrolysis of the fractions in calcium acetate buffer (pH 3.5) followed by separation of the resulting free lipid A from the polysaccharide on a Sephadex G-100 column. Chemical analysis revealed that lipid A of the R fraction contained the expected spectrum and amounts of fatty acids and it proved to be structurally identical to lipid A of previously studied Salmonella R mutants. In contrast, the lipid A of the long-chain fraction contained only about 60% fatty acids compared to that of the R fraction. The lipid A of the short-chain fraction also expressed a reduced substitution pattern of acyl residues.

Acetates↗

PubMed1991

Chemical structure of the carbohydrate backbone of Vibrio parahaemolyticus serotype 012 lipopolysaccharide.

The chemical structure of the saccharide portion of Vibrio parahaemolyticus serotype 012 lipopolysaccharide was studied. Using chemical degradation and modification, as well as methylation analysis in combination with GLC-MS, laser-desorption mass spectrometry and 1H-NMR and 13C-NMR spectroscopy, the carbohydrate backbone of the lipopolysaccharide was characterized as a branched decasaccharide with the following structure: (formula; see text) In the native lipopolysaccharide two additional phosphate groups are present and 3-deoxy-D-threo-hexulosonic acid and D-galacturonic acid are bound via acid-labile linkages.

Carbohydrate Conformation↗

PubMed1992

Preferential synthesis of heptaacyl lipopolysaccharide by the ssc permeability mutant of Salmonella typhimurium.

In Salmonella typhimurium, a chromosomal gene termed ssc has been shown to cause an antibiotic-supersensitive phenotype. We studied the effect of the ssc gene on the chemical composition of the lipopolysaccharide component, using a thermosensitive ssc1 mutant (SH7622) that grows poorly at 42 degrees C. Analysis of the lipopolysaccharide by various techniques including fast-atom-bombardment mass spectrometry of lipid A, and determination of the type of linkage of fatty acids, revealed a profound temperature-dependent effect associated with the ssc1 mutation. At the non-permissive temperature, SH7622 contained hexadecanoic acid in the majority of lipid A molecules, resulting in the exclusive presence of heptaacyl lipopolysaccharide. This effect was largely reversed by the introduction of the cloned wild-type ssc gene to SH7622 and much reduced by growth of SH7622 at 37 degrees C.

Carbohydrate Sequence↗

PubMed1992

The structure of the O-antigenic polysaccharide from lipopolysaccharide of Vibrio cholerae strain H11 (non-O1).

After acid degradation of the lipopolysaccharide (LPS) of Vibrio cholerae strain H11 (non-O1), a tetrasaccharide was obtained, the structure of which was determined by quantitative and methylation analyses, periodate oxidation, one- and two-dimensional NMR spectroscopy, and fast-atom-bombardment and four-sector tandem mass spectrometry as beta-D-GalANGro-(1-3)-beta-D-QuiNAc-(1-4)-alpha-D-GalANGr o-(1-4)-NeuAc, in which GalANGro is N-galacturonoyl-2-aminoglycerol and QuiN 2-amino-2,6-dideoxy-glucopyranose. In addition, the trisaccharide beta-D-GalANGro-(1-3)-beta-D-QuiNAc-(1-4)-D-altro-hept ulose and the disaccharide alpha-D-GalANGro-(1-4)-NeuAc were isolated from acid-degraded lipopolysaccharide; the occurrence of sedoheptulose in lipopolysaccharide has not been described before. Based on the result of methylation analysis showing that galacturonic acid was the terminal sugar of the polysaccharide chain, and on the assumption that the tri- and the disaccharide represented the reducing and the non-reducing ends of the polysaccharide, respectively, the chemical structure of the O-specific chain of V. cholerae H11 is proposed as alpha-D-GalANGro-(1-4)-alpha-NeuAc-(2-3)-beta-D-GalANGro-(1- 3)-beta-D-QuiNAc- (1-[4)-alpha-D-GalANGro-(1-4)-alpha-NeuAc-(2-3)-beta-D-GalANGro -(1-3)-beta-D- QuiNAc-(1-]n-(1-4)-D-altro-heptulose. However, other possible structures can not be ruled out since the tri- and the disaccharide could be localised at different positions.

Carbohydrate Conformation↗

PubMed1993

Comparison of X-ray powder-diffraction data of various bacterial lipopolysaccharide structures with theoretical model conformations.

X-ray powder-diffraction experiments have been performed on dry samples of lipid A and various rough-mutant lipopolysaccharides (LPS) of Salmonella minnesota, Salmonella typhimurium and Escherichia coli. The diffraction patterns obtained indicated exclusively lamellar, bilayered arrangements in all samples. The periodicities were found to be in the range 4.5 nm for lipid A to 8.8 nm for Ra-LPS. Upon treatment with water-saturated air, swelling of the lamellar structures was achieved, as indicated by shifts of reflections. The increase in bilayer dimensions normally was about 0.3 nm. X-ray intensities were used for the determination of the inner bilayer structure, i.e. for calculation of the one-dimensional electron-density distribution across the bilayer. For lipid A and several Re-LPS, Rd2-LPS, Rd1-LPS and Rc-LPS samples, a striking coincidence of the electron-density distributions in the lipid-A domain was found, suggesting that in all these structures the lipid-A portion is similarly arranged. For Rb1 and Ra-LPS the lipid-A domain could not be resolved due to the limited number of observed reflections. For other Re-mutant lipopolysaccharide samples, quite different X-ray patterns were obtained. Some samples yielded diffraction patterns indicating a very high state of order in the lipid-A domain, whereas, in others, a significantly reduced order in the lipid-A domain was inferred. Comparison of the X-ray data with features of a calculated three-dimensional molecular model of lipopolysaccharide revealed reasonable agreement in molecular dimensions and bilayer structure.

Escherichia coli↗

PubMed1994

Isolation and structural analysis of oligosaccharide phosphates containing the complete carbohydrate chain of the lipopolysaccharide from Vibrio cholerae strain H11 (non-O1).

For the first time, an oligosaccharide has been prepared comprising the lipid A backbone, the core oligosaccharide and one repeating unit of the O-specific polysaccharide (O-chain) of a lipopolysaccharide. Lipopolysaccharide from Vibrio cholerae strain H11 (non-O1) was deacylated and the products were separated by high-performance anion-exchange chromatography. Major fractions were a hexadecasaccharide trisphosphate 1, representing the core-lipid A oligosaccharide substituted by one modified repeating unit of the O-antigenic polysaccharide, a dodecasaccharide trisphosphate 2 and an undecasaccharide trisphosphate 3, representing the core-lipid A region. Oligosaccharide 1 originated from beta-elimination upon alkaline hydrolysis of alpha-galacturonic acid of the O-chain; oligosaccharides 2 and 3 were most likely obtained from naturally occurring lipopolysaccharide species carrying no O-chain. The structures of these compounds were elucidated on the basis of monosaccharide composition, and NMR investigations comprising correlation spectroscopy, total correlation spectroscopy and nuclear Overhauser enhancement spectroscopy experiments, as well as heteronuclear 13C, 1H correlation spectroscopy. The structures are as follows: [formula: see text] where R is beta-L-threo-hex-4-enuronopyranosyl-(1-4)-alpha-Neu-(2-3)-beta-Gal A-(1-3)- beta-QuiN-(1-4)-beta-Sedf-(2- in 1, beta-Sedf-(2- in 2, and H in 3. Where not stated otherwise, sugars are pyranoses of the D-series. Hep is L-glycero-D-manno-heptose, QuiN is 2-amino-2,6-dideoxy-glucose, Kdo is 3-deoxy-D-manno-2-octulosonic acid, Sed is D-altro-heptulose and GalA is galacturonic acid.

Carbohydrate Sequence↗

PubMed1994

Structure of the Escherichia coli O24 and O56 O-specific sialic-acid-containing polysaccharides and linkage of these structures to the core region in lipopolysaccharides.

The lipopolysaccharides from Escherichia coli O24 and O56 could be separated into higher-molecular-mass and lower-molecular-mass fractions. Mild acid hydrolysis of lipopolysaccharides of both serotypes released an O-specific polysaccharide and a tetrasaccharide repeating unit. Oligomers of the repeating unit, the core and the oligosaccharide that contains a fragment of the repeating unit linked to the core region were also obtained according to hydrolysis conditions. On the basis of sugar and methylation analyses, Smith degradation, fast-atom-bombardment mass spectrometry and NMR spectroscopy of the hydrolysis products, the biological repeating units of the O-specific polysaccharides were shown to be the following tetrasaccharides: [formula: see text] The structures differ from the structures proposed previously by Kogan et al. [Kogan, G., Shashkov, A. S., Jann, B. & Jann, K. (1993) Carbohydr. Res. 238, 261-270; Kogan, G., Jann, B. & Jann, K. (1993) Carbohydr. Res. 238, 335-338]. The O-specific repeating unit in E. coli O24 lipopolysaccharide is linked to O6 of the terminal D-galactose in the core region, whereas in O56 LPS the repeating unit is linked to O4 of a subterminal D-glucose residue in an R2 type core.

Carbohydrate Conformation↗

PubMed1994

Induction of cytosolic phospholipase A2 in human leukocytes by lipopolysaccharide.

Stimulation of peripheral blood leukocytes with lipopolysaccharide results in the synthesis of inflammatory cytokines including interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha and prostaglandin E2 correlating with an increase in phospholipase A2 activity. Mammalian cells contain several phospholipase A2 isoforms including the 14-kDa secretory isoform and the more recently described high-molecular-mass cytosolic isoform. It is commonly believed that during inflammatory responses secretory phospholipase A2 becomes activated. However, we could not detect secretory phospholipase A2 nor its corresponding mRNA after lipopolysaccharide-induced activation. By contrast, we found increased mRNA levels for cytosolic phospholipase A2 following activation of peripheral blood leukocytes when levels were compared to non-stimulated controls. Our results demonstrate that cytosolic phospholipase A2, rather than the secretory isoform may be the mediator of the lipopolysaccharide-induced inflammatory cascade in human peripheral blood leukocytes.

Base Sequence↗

PubMed1997

Structural and serological characterisation of the O-specific polysaccharide from lipopolysaccharide of Acinetobacter calcoaceticus strain 7 (DNA group 1).

S-form lipopolysaccharide was isolated by phenol/water extraction from a strain of Acinetobacter calcoaceticus (DNA group 1 ). The structure of the O-antigenic polysaccharide was determined by compositional analysis and NMR spectroscopy of the de-O-acylated lipopolysaccharide. The isolated polysaccharide obtained after hydrolysis of lipopolysaccharide in 0.01 M trifluoroacetic acid has the following structure: [STRUCTURE IN TEXT] in which Pyr is pyruvate. The O-acetyl substitution of D-Gal was non-stoichiometric. The O-antigen was specifically recognised in western blots by polyclonal rabbit antisera.

Acinetobacter calcoaceticus↗

PubMedDate not supplied

Effects of post-treatment with low-dose propofol on inflammatory responses to lipopolysaccharide-induced shock in conscious rats.

1. In the present study, we used a low dose of propofol (5 mg/kg per h) to investigate its effects on the pro-inflammatory cytokines (tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-10) and changes in nitric oxide (NO) following lipopolysaccharide (LPS) for a period of 12 h in conscious rats. 2. Experiments were designed to induce endotoxin shock by intravenous injection of Klebsiella pneumoniae LPS (10 mg/kg) in conscious rats. Arterial pressure (AP) and heart rate (HR) were monitored continuously for 12 h after LPS administration. Tumour necrosis factor-alpha, IL-1beta, IL-10 and plasma nitrates/nitrites were determined before and 0.5, 1, 3, 6, 9 and 12 h after LPS administration. A low dose of intravenous propofol (5 mg/kg per h) was administered to investigate the effects on cytokine responses and changes in NO in endotoxin shock. 3. Lipopolysaccharide significantly increased TNF-alpha, IL-1beta, IL-10, nitrites/nitrates and HR, whereas mean AP was decreased. Post-treatment with propofol suppressed the release of TNF-alpha, IL-1beta, IL-10 and NO production after endotoxin shock. 4. Lipopolysaccharide also caused a decrease in the white blood cell count and haematocrit. 5. Post-treatment with propofol slightly, but not significantly, affected the LPS-induced systemic hypotension, tachycardia, leukocytopenia and anaemia. 6. These findings suggest that low-dose propofol may be beneficial to the inflammatory change in sepsis.

Animals↗

PubMed1995

Lipopolysaccharide core region of Hafnia alvei: serological characterization.

Covalent glycoconjugates containing, as a ligand lipopolysaccharide core, oligosaccharides of Hafnia alvei standard strain ATCC 13337 and R mutant 1 M were used to produce anti-H. alvei core antibodies. The sera obtained were tested in rocket immunoelectrophoresis, immunoblotting and ELISA using H. alvei lipopolysaccharides of various strains. The experiments were carried out to study the antigenic relationships between lipopolysaccharide core regions in the H. alvei genus.

Animals↗

PubMed1996

Anti-endotoxin antibodies directed against Escherichia coli R-1 oligosaccharide core-tetanus toxoid conjugate bind to smooth, live bacteria and smooth lipopolysaccharides and attenuate their tumor necrosis factor stimulating activity.

The reactivity of anti-OS R1-tetanus toxoid serum with various smooth and rough lipopolysaccharides have been determined in enzyme-linked immunosorbent assay (ELISA) and with intact, live smooth bacterial cells in flow cytometry. All tested smooth lipopolysaccharides of R1 core type belonging to nine different O-serotypes reacted strongly with anti-conjugate antibodies. Flow cytometry showed that anti-core antibodies labelled more than 95% of bacterial cells with high intensity of fluorescence. The anti-conjugate serum was able to react with free form of smooth lipopolysaccharides and to inhibit their TNF stimulation activity in in vitro and in vivo models.

Animals↗

PubMed1999

The lipopolysaccharide core type of Escherichia coli O157:H7 and other non-O157 verotoxin-producing E. coli.

A mouse monoclonal antibody specific for the R3 lipopolysaccharide core type of Escherichia coli was used to determine the core type of E. coli O157:H7 and other non-O157 verotoxin-producing E. coli strains. Lipopolysaccharide extracts from 28 clinical isolates were examined by sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting and all were found to have the R3 core. None of the core lipopolysaccharide from the strains tested reacted with the control R1 and R2 specific monoclonal antibodies. A common core type between all the verotoxin-producing E. coli strains tested may be significant when considering the immune response to these bacteria, and to the receptor for the VT bacteriophage.

Animals↗

PubMed2006

Structures of the core oligosaccharide and O-units in the R- and SR-type lipopolysaccharides of reference strains of Pseudomonas aeruginosa O-serogroups.

Highly phosphorylated core oligosaccharides and those substituted with one O-antigen repeating unit were obtained by mild acid degradation or strong alkaline hydrolysis of lipopolysaccharide samples from 23 reference strains representing all Pseudomonas aeruginosa O-serogroups. Studies by high-resolution electrospray ionization mass spectrometry and two-dimensional NMR spectroscopy revealed both conserved and variable structural features of the lipopolysaccharides of various O-serogroups. The upstream terminal saccharide of the O-antigen, which contributes most to the immunospecificity of the bacteria, was defined in 11 from a total of 13 O-serogroups. The data obtained link together the known biosynthesis pathways, genetics and serology of the P. aeruginosa lipopolysaccharide.

Carbohydrate Conformation↗

PubMed2006

Structure of the glycerol phosphate-containing O-polysaccharides and serological studies of the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 classified into a new Proteus serogroup, O54.

O-Polysaccharides were obtained from the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 and studied by chemical analyses and one- and two-dimensional (1)H and (13)C nuclear magnetic resonance spectroscopy, including rotating-frame nuclear Overhauser effect spectroscopy, H-detected (1)H,(13)C heteronuclear single-quantum spectroscopy and (1)H,(31)P heteronuclear multiple-quantum spectroscopy experiments. The Proteus mirabilis OE polysaccharide was found to have a trisaccharide repeating unit with a lateral glycerol phosphate group. The Proteus vulgaris TG 103 produces a similar O-polysaccharide, which differs in incomplete substitution with glycerol phosphate (c. 50% of the stoichiometric amount) and the presence of an O-acetyl group at position 6 of the 2-acetamido-2-deoxygalactose (GalNAc) residue. These structures are unique among the known bacterial polysaccharide structures. Based on the structural and serological data of the lipopolysaccharides, it is proposed to classify both strains studied into a new Proteus serogroup, O54, as two subgroups, O54a,54b and O54a,54c. The serological relatedness of the Proteus O54 and some other Proteus lipopolysaccharides is discussed.

Carbohydrate Sequence↗

PubMed2006

Structure and heterogeneity of the O-antigen chain of Salmonella Agona lipopolysaccharide.

Lipopolysaccharide of Salmonella Agona smooth-type cells was obtained from bacteria by a hot phenol-water extraction procedure. Mild acid hydrolysis of lipopolysaccharide, followed by gel filtration, yielded the pure O-polysaccharide. Abequose, rhamnose, mannose, galactose and glucose in the molar ratio 0.8 : 1.0 : 1.0 : 1.1 : 0.5 were detected, and their linkages were established. Sugar configurations were determined by gas chromatography. Two repeating units, namely -->2)-[alpha-Abep-(1-->3)-]-alpha-d-Manp-(1-->4)-alpha-l-Rhap-(1-->3)-alpha-d-Galp-(1-->and -->2)-[alpha-Abep-(1-->3)-]-alpha-d-Manp-(1-->4)-alpha-l-Rhap-(1-->3)-[alpha-d-Glcp-(1-->4)-]-alpha-d-Galp-(1-->, were deduced from nuclear magnetic resonance studies. The effort to separate them was unsuccessful. An immunochemical test performed by means of Western blotting with anti O12 serum demonstrated that glucose was present in the longer lipopolysaccharide chains, at some distance from the core region.

Carbohydrate Conformation↗