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PubMed1993

The role of galE in the biosynthesis and function of gonococcal lipopolysaccharide.

Lipopolysaccharide is an essential component of the outer membrane of Gram-negative bacteria and an important virulence factor of many pathogens, such as Neisseria gonorrhoeae. We have cloned the gonococcal galE gene which was found to be located in the gonococcal homologue of the meningococcal capsule gene complex region D. Sequence alignment indicated extensive homology with the Escherichia coli and Salmonella GalE proteins. Mutants with insertions in the galE gene were used as a tool to characterize the structure and function of gonococcal lipopolysaccharide. They displayed deep rough phenotypes, and chemical analysis confirmed the loss of galactose from the mutant lipopolysaccharide. Functional analysis indicated that the terminal oligosaccharides contain galactose and that these are lost in galE mutants. The importance of these oligosaccharides in gonococcal biology is clear from the fact that they contain the epitopes that are the targets for killing by normal human serum, and the acceptor site for sialic acid, which acts to protect the gonococcus from this killing. Furthermore, infection experiments in vitro indicate that the galE mutants exhibit unaltered intergonococcal adhesion as well as adhesion to, and invasion of, epithelial cells.

Amino Acid Sequence↗

PubMed1975

Genetic control of B-cell responses. I. Selective unresponsiveness to lipopolysaccharide.

Spleen cells from C3H/HeJ mice fail to develop both proliferative responses and increased polyclonal antibody secretion in the presence of concentrations of the B-cell mitogen lipopolysaccharide that are optimal for the induction of B-cell responses in conventional strains. This unresponsiveness is selective for lipopolysaccharide, since C3H/HeJ spleen cells respond normally to two other polyclonal B-cell activators-dextran-sulphate and purified protein derivative of tuberculin. These findings are interpreted as indicating a selective defect in the B-cell subpopulation that responds to lipopolysaccharides in conventional strains.

Activation Analysis↗

PubMed1991

Virus, bacteria and lipopolysaccharide increase basophil cell response to histamine releasing stimulators and calcium. Examination of allergic and normal individuals.

Histamine release from human basophil leukocytes from allergic patients or controls was induced by specific antigens, anti-IgE or calcium ionophore A23187. Influenza A virus, S. aureus and lipopolysaccharide from S. typhimurium increased the maximum release of histamine and caused a shift to the left of the dose-response curves showing increased cell sensitivity and lowering of the threshold to these stimuli. The mechanism of action was elucidated by examining the mediator release as a function of increasing extracellular concentration of calcium. In these experiments the dose-response curves were changed by the microorganisms and lipopolysaccharide as before. This indicates that the microorganisms and lipopolysaccharide change the basophil cell response to IgE-dependent and non-immunological stimuli by causing a change in the subcellular handling of calcium.

Adult↗

PubMed1975

Cell-wall lipopolysaccharide from Escherichia coli B.

The lipopolysaccharide of Escherichia coli BB and a number of R-phage selected (e.g. T3, T4) cell-wall-defective mutants were analyzed. From their lipopolysaccharides the respective core oligosaccharides were obtained. Following dephosphorylation, the oligosaccharides were methylated and analyzed by gas chromatography/mass spectrometry. This revealed the sugar sequence in the hexose-heptose region of the core. The linkage of heptose (Hep) to 2-keto-3-deoxyoctonate (KDO) was established as ... Hep 1,5 leads to KDO ... by methylation analysis. The substituted derivative of KDO was identified by gas chromatography and mass spectrometry. The KDO region contains three KDO units. Its structure was elaborated by (a) selective removal and identification of 7-phosphoryl ethanolamine-KDO (KDO-PN), (b) periodate oxidation and thiobarbituric acid reaction in conjunction with mild hydrolysis, (c) a modified methylation analysis. Phosphate substitution of E. coli BB core was studied by beta-elimination and using the information obtained with KDO-PN. The structures of the cell wall lipopolysaccharides from E. coli BB and cell-wall-defective mutants are given.

Chromatography, Gas↗

PubMed1975

Asymmetrical distribution and artifactual reorientation of lipopolysaccharide in the outer membrane bilayer of Salmonella typhimurium.

Labelling of cell walls or outer membranes from Salmonella typhimurium with ferritin-conjugated antibodies directed against the polysaccharide moiety of the lipopolysaccharide gave the following results: 1. Cell walls or outer membranes from which the mucopeptide had been removed by lysozyme digestion at 0 degrees C carried the label on the outer face of the membrane. 2. When the murein layer was removed by either lysozyme or trypsin at physiological temperature (25-37 degrees C) subsequent labelling showed the lipopolysaccharide to be present on both membrane faces. 3. This reorientation could be achieved by a 1-min treatment of the membranes at 37 degrees C. 4. Glutaraldehyde fixation of the outer membranes did not entirely prevent but somewhat inhibited the temperature-induced reorientation process. 5. The same reorientation phenomenon was observed in lysozyme spheroplasts, which were prepared at 37 degrees C and were subsequently lysed in hypotonic medium at 0 degrees C. These observations are discussed as evidence for a transmembrane movement of lipopolysaccharide, which only takes place in areas where the mucopeptide layer is defective, and only when the temperature is sufficiently high to allow such movement.

Antigen-Antibody Reactions↗

PubMed1976

Absolute configuration of 3-hydroxy fatty acids present in lipopolysaccharides from various bacterial groups.

The absolute configuration of 3-hydroxy fatty acids has been studied, which are present in the lipopolysaccharides of the following bacteria: Phodopseudomonas gelatinosa, Rh. viridis, Rhodospirillum tenue, Chromobacterium violaceum, Pseudomonas aeruginosa, Bordetella pertussis, Vibrio metchnikovii, Vibrio cholerae, Salmonella spp., Escherichia coli, Shigella flexneri, Proteus mirabilis, Yersinia enterocolitica and Fusobacterium nucleatum. The 3-hydroxy acids were liberated by strong alkaline hydrolysis, converted to 3-methoxy acid L-phenylethylamides and analyzed by gas-liquid chromatography. With the aid of authentic D-3-hydroxy fatty acids it was shown for all lipopolysaccharides that the 3-hydroxy acids, regardless of chain lengths, branching, 3-O-substitution or type of linkage, possess the D-configuration. 2-Hydroxydodecanoic acid, which is present in some lipopolysaccharides, was analyzed in an analogous way and shown to possess the L-configuration.

Binding Sites↗

PubMed1977

Ribitol-containing lipopolysaccharides from Proteus mirabilis and their serological relationship.

Ribitol phosphate was recently identified as a constituent of lipopolysaccharides obtained from 'proteus mirabilis strain D52 giving 1:4-anhydroribitol during acid hydrolysis (Gmeiner, 1975). Two other Proteus mirabilis strains belonging to serogroups O16 and O33 were shown previously to contain an unknown compoound X as lipopolysaccharide constituent (Kotelko et al., 1975). In this report the identification of compound X as 1:4-anhydroribotol by gas-liquid chromatography, mass spectrometry and mass fragmentography is described. Serological investigations using passive hemagglutination, hemagglutination inhbition and semi-quantitative precipitin reactions indicate strongly that ribitol plays a role in the serological specificity of the respective lipopolysaccharides.

Hemagglutination Inhibition Tests↗

PubMed1978

L-2-hydroxytetradecanoic acid as a constituent of Salmonella lipopolysaccharides (lipid A).

L-2-Hydroxytetradecanoic acid was recognized as a characteristic, although minor, constituent of the lipid A component of Salmonella lipopolysaccharides. The 2-hydroxy fatty acid was present in lipid A as an ester, probably bound to the hydroxyl group of some D-3-hydroxytetradecanoic acid residues. A survey of enterobacterial lipopolysaccharides showed that L-2-hydroxytetradecanoid acid was also present in Klebsiella and Serratia strains. It was absent, however, from lipopolysaccharides of other genera of the family including Escherichia, Shigella, Proteus, Enterobacter and Yersinia. This restricted distribution of the 2-hydroxy acid may be of significance for taxonomic studies of bacterial genera.

Enterobacteriaceae↗

PubMed1980

Structural studies of the lipopolysaccharide from Salmonella typhimurium 902 (ColIb drd2).

Salmonella typhimurium infected with the plasmid ColIb drd2 gave rise to changes in the composition of the bacterial lipopolysaccharide. Bacteria carrying the wild-type ColIb, the revertant of drd2 to the wild type, or the noncolicinogenic strain resulting from the elimination of ColIb drd2, showed no changes in the sugar composition of the lipopolysaccharide. The structure of the O-specific side chains of the lipopolysaccharide produced by S. typhimurium 902, infected with derepressed ColIb mutants has been investigated. As a result of these studies, it is proposed that the O-specific side chains are composed of chemical repeating units with the following structure: (formula: see text).

Carbohydrate Sequence↗

PubMed1982

Involvement of prostaglandin E and adenosine 3', 5'-monophosphate in lipopolysaccharide-stimulated collagenase release by rat Kupffer cells.

Kupffer cells exposed to bacterial lipopolysaccharide in vitro synthesized collagenase and released the major portion of it into the extracellular space while the intracellular level of enzyme was not altered significantly. Cycloheximide prevented the appearance of collagenase in the medium indicating de novo synthesis. Indomethacin, an inhibitor of cyclooxygenase, also blocked collagenase synthesis. In line with this observation. Kupffer cells were found to synthesize substantial amounts of prostaglandin E2 when exposed to lipopolysaccharide; concomitantly, cellular cAMP levels were increased. Indomethacin was shown to abolish the stimulated cAMP formation. Addition to the culture medium of cAMP or dibutyryladenosine 3', 5'-monophosphate as well as of prostaglandin E2 or, to a lesser extent, prostaglandin E1 allowed indomethacin-inhibited cells to resume the production of collagenase. It is proposed that in rat Kupffer cells lipopolysaccharide-elicited collagenase synthesis and excretion is mediated sequentially by stimulated production of prostaglandin E2, enhanced adenylate cyclase activity and increased intracellular cAMP levels.

Animals↗

PubMed1982

Somatic Antigens of Pseudomonas aeruginosa. The structure of the polysaccharide chain of Ps.aeruginosa O:6 (Lanyi) lipopolysaccharide.

An O-antigenic lipopolysaccharide, manifesting a high serological activity in the reaction of passive haemagglutination and its inhibition, was isolated from Pseudomonas aeruginosa O:6 cells (Lanyi). Splitting-off of the lipid component by mild acid hydrolysis resulted in the polysaccharide deprived of O-specific activity. The polysaccharide chain of the lipopolysaccharide was made up exclusively of the residues of amino sugars, among which have been identified: 2-acetamido-2-deoxy-D-galactose (GalNAc), 2-acetamido-2,6-dideoxy-D-glucose (QuiNAc), 2-acetamido-2,6-dideoxy-D-galactose (FucNAc) as well as 2,3-diacetamido-2,3-dideoxy-D-glucuronic acid [Glc(NAc)2A] found naturally for the first time. The principal methods of establishing the polysaccharide structure were 13C nuclear magnetic resonance, methylation analysis and solvolysis with hydrogen fluoride. Depending on solvolysis conditions, a disaccharide or a trisaccharide containing the diacetamidouronic acid residue was formed. From the results obtained it followed that the polysaccharide chain of the O-antigenic Ps. aeruginosa O:6 lipopolysaccharide represents an acidic hexasaminoglycan constructed of the repeating tetrasaccharide units of the following structure: leads to 4)DGalNAc(alpha 1 leads to 4)DGlc(NAc)2A(beta 1 leads to 3)DFucNAc(alpha 1 leads to 3)DQuiNAc(alpha 1 leads to.

Chemical Phenomena↗

PubMed1983

Aberrant migration of lipopolysaccharide in sodium dodecyl sulfate/polyacrylamide gel electrophoresis.

Purified lipopolysaccharides of salmonellae strains were separated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Pre-electrophoresis of polyacrylamide gels had no apparent effect on one-dimensional silver-stained lipopolysaccharide profiles. However, without pre-electrophoresis, two-dimensional and three-dimensional patterns contained numerous bands with varied migration patterns compared to those in the one-dimension gels. The lipopolysaccharide was altered within the polyacrylamide gel during electrophoresis. Pre-electrophoresis of gels eliminated aberrant migration patterns.

Electrophoresis, Polyacrylamide Gel↗

PubMed1983

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↗

PubMed1984

Structure of the O-chain of the phenol-phase soluble cellular lipopolysaccharide of Yersinia enterocolitica serotype O:9.

The phenol-phase soluble cellular lipopolysaccharide isolated by the phenol/water extraction method from Yersinia enterocolitica serotype O:9 cells was shown by hydrolytic, periodate oxidation, methylation and nuclear magnetic resonance studies to be an S-type lipopolysaccharide with a linear O-antigenic polysaccharide of 1,2-linked 4,6-dideoxy-4-formamido-alpha-D-mannopyranosyl units. The serological cross-reactivity between Y. enterocolitica serotype O:9 and the lipopolysaccharides of Vibrio cholerae and Brucella species can now be related to the presence of N-acylated 4-amino-4,6-dideoxy-alpha-D-mannopyranosyl residues in their respective O-antigenic chains.

Antigens, Bacterial↗

PubMed1984

The structure of the polysaccharide moiety of Rhodopseudomonas sphaeroides ATCC 17023 lipopolysaccharide.

The chemical structure of the polysaccharide moiety of the lipopolysaccharide Rhodopseudomonas sphaeroides ATCC 17023 was established. Mild acetic acid hydrolysis of isolated lipopolysaccharide, followed by preparative high-voltage paper electrophoresis afforded three oligosaccharides. They were characterized by chemical and physicochemical studies to be: GlcA(alpha 1----4)dOclA8P, Thr(6') GlcA(alpha 1----4)GlcA and GlcA(alpha 1----4)dOclA, where GlcA is D-glucuronic acid and dOc1A is 3-deoxy-D-manno-octulosonic acid. Carboxyl-reduction of the lipopolysaccharide followed by acid hydrolysis gave a trisaccharide: GlcA(alpha 1----4)Glc(alpha 1----4)Glc, showing the presence of three residues of glucuronic acids in the O-specific chain and indicating that only two of them are reducible by NaBH4. The linkage between the polysaccharide and lipid A was shown to be through a single 1,4-linked residue of dOc1A attached by a 2,6'-linkage to the lipid A moiety.

Chemical Phenomena↗

PubMed1985

Structural studies on O-specific polysaccharides of lipopolysaccharides from Yersinia enterocolitica serovars O:1,2a,3, O:2a,2b,3 and O:3.

Lipopolysaccharides from Yersinia enterocolitica serovars O:1,2a,3, O:2a,2b,3 and O:3 have been isolated and characterized. 6-Deoxy-L-altrose residues were shown to be the main constituents of lipopolysaccharides isolated in addition to residues of L-rhamnose, D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-glycero-D-manno-heptose and L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid being minor components of sugar chains. Mild hydrolysis of lipopolysaccharides with acetic acid furnished O-specific polysaccharides, which are composed of 6-deoxy-L-altrose. Using 13C-NMR spectroscopy and methylation data, the structural features of backbones have been elucidated as follows: ----2)-6d-L-Altp(beta 1----2)-6d-L-Altp(beta 1----3)-6d-L-Altp)(beta 1----for serovars O:1,2a,3 and O:2a,2b,3;----2)-6d-L-Altp(beta 1----for serovar O:3. In addition, O-polysaccharide of serovar O:2a,2b,3 was found to contain an O-acetyl group at the C-3 position of some 1,2-linked sugar residues.

Antigens, Bacterial↗

PubMed1985

Structural studies of the polysaccharide part of the cell wall lipopolysaccharide from Bacteroides fragilis NCTC 9343.

The structure of the polysaccharide part of the lipopolysaccharide from Bacteroides fragilis NCTC 9343 has been determined using sugar and methylation analysis as the principal tools. Phenol--water extraction followed by a phenol--chloroform--light petroleum extraction yielded a lipopolysaccharide suitable for structural analysis. Analysis of sugars using alditol acetates showed that the polysaccharide contained L-rhamnose, D-galactose and D-glucose in the approximate molar ratios of 1:5:1. After weak acid hydrolysis, two polysaccharide fractions were isolated by gel permeation chromatography: PSI and PSII with the sugar molar ratios 1:5:1 and 1:2:1 respectively. Chromium trioxide oxidation revealed that all galactosyl residues have the beta configuration, and that the rhamnosyl and glucosyl residues have the alpha configuration. From methylation analysis of lipopolysaccharide and the PS I and PS II fractions the following structures could be deduced.

Bacteroides fragilis↗

PubMed1986

In vitro deacylation of lipopolysaccharide of Salmonella minnesota by Acanthamoeba castellanii enzymes.

Enzymatic deacylation of the lipopolysaccharide isolated from a Salmonella Rd mutant by a cell-free preparation from Acanthamoeba castellanii has been studied. The degradation was found to be dependent on the presence of a surface-active component (Triton X-100) in the reaction mixture. The lipid A part of the lipopolysaccharide was the primary target of the enzymes, which cleaved with high efficiency the ester-bound long-chain nonhydroxylated and 3-hydroxylated acyl residues, i.e. lauric, myristic, palmitic and 3-hydroxymyristic acid. The cell-free preparation also exhibited amidase activity cleaving about 50% of the amide-bound 3-hydroxymyristic acid residues. In addition the extract proved to possess phosphatase activity liberating ester-bound and glycosidically bound phosphate groups of lipid A. On the other hand, the glucosaminyl-beta 1,6-glucosamine disaccharide was not degraded and remained bound to the oligosaccharide part (heptose/3-deoxyoctulosonic acid) of the lipopolysaccharide.

Amidohydrolases↗