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

We describe here the isolation, purification, and structural characterization of a lipid A precursor synthesized under nonpermissive conditions by a mutant of Salmonella typhimurium conditionally defective in the synthesis of the 3-deoxy-D-mannoctulosonate (2-keto-3-deoxyoctonate, KDO) region of the lipopolysaccharide. The precursor was isolated free from lipopolysaccharide, murein, and phospholipids by extraction of delipidated cells with 90% phenol/CHCL3/petroleum ether. The molecule was recovered from the phenol phase after precipitation of lipopolysaccharide with H2O and subsequently purified by DEAE-cellulose chromatography. Structural analyses showed that the lipid A precursor is a phosphorylated glucosamine disaccharide containing one ester and two amide-linked residues of beta-hydroxymyristate. In contrast to lipid A, the precursor disaccharide lacks ester-linked 12:0 and 14:0 fatty acids as well as KDO. The molecule contains 2 phosphate residues both of which were identified as phosphomonoesters by 31P NMR spectroscopy. One of the phosphomonoesters is located in position 1 of the reducing terminal glucosamine residue; the location of the other phosphomonoester was not determined. The structure of the precursor provides strong support for the conclusion that KDO incorporation occurs at an early stage in lipid A biosynthesis prior to the incorporation of ester-linked saturated fatty acids.
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PMID:Lipid A mutants of Salmonella typhimurium. Purification and characterization of a lipid A precursor produced by a mutant in 3-deoxy-D-mannooctulosonate-8-phosphate synthetase. 1 8

Salmonella typhimurium mutants, called Felix O-resistant (FOR), selected for resistance to phage Felix O (FO) which has its receptor in the core lipopolysaccharide (LPS), retain most of the properties of the smooth parent strain (MacPhee, Krishnapillai, Roantree & Stocker, 1975). LPS extracted from one parent and two FOR strains by the phenol-water and the phenol-chloroform-light petroleum methods have been subjected to passive haemagglutination inhibition and methylation analysis. The amount of LPS, the amount of O-specific sugars in the LPS, and the average length of the O chains were almost the same in parent and mutant strains. Neither passive haemagglutination nor methylation analysis revealed the presence of incomplete cores in the mutant strains. Determination of the rates of attachment of P22 (receptor in O chain) and FO phages to whole bacteria of the same strains also suggested there is as much O-chain material in the FOR strains as in the parent strain. The data suggest that the FOR strains are the result of a mutation in the synthesis of the core, leaving few, if any, completed cores accessible to the FO phage.
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PMID:Salmonella typhimurium mutations conferring resistance to Felix O phage without loss of smooth character: phage attachment and immunochemical and structural analyses of lipopolysaccharides. 4 37

Adaptations of the Farr technique have resulted in a specific and reproducible radioactive antigen-binding assay for antibodies directed against the lipopolysaccharide (LPS) of Neisseria meningitidis. LPS was intrinsically labeled with 14C acetate during 16-hr growth in a modified Frantz media, extracted by hot phenol-H2O, and purified by dialysis, ultracentrifugation, and ethanol precipitation. LPS, which aggregates in aqueous solutions, was maintained in a monomeric form in 3% sodium deoxycholate (NaD) as determined by gel filtration on Sephadex G-75. Since NaD is insoluble in (NH4)2SO4, polyethylene glycol, 20%, was used to precipitate immunoglobulins of all three major classes.
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PMID:Response to antigenic determinants of Neisseria meningitidis lipopolysaccharide investigated with a new radioactive antigen-binding assay. 5 1

The lipopolysaccharide (LPS)-protein complex extracted from the cell wall of Escherichia coli K235 by the butanol-water technique has been shown to evoke a mitogenic response in bone marrow-derived (B) lymphocytes from the C3H/HeJ mouse strain. These mice are resistant to the effects of LPS extracted with phenol. Therefore, the ability of butanol-extracted LPS to modulate a spectrum of C3H/HeJ B-cell functions was investigated. Both butanol-extracted (LPS-B) and phenol-extracted (LPS-P) LPS preparations activated responder C3H/St spleen cell cultures to polyclonal antibody production, while only LPS-B activated C3H/HeJ spleen cells. Both LPS-P and LPS-B acted as adjuvants when injected after aggregated human gamma globulin (HGG) in C3H/St mice, but neither preparation was effective as a adjuvant in C3H/HeJ mice. LPS-P injected with deaggregated HGG (tolerogen) into LPS-sensitive mice has been shown previously to inhibit the induction of tolerance HGG. In the present studies, it was shown that LPS-B, but not LPs-p, was able to inhibit tolerance induction to HGG in the C3H/HeJ, whereas both preparations were effective in the C3H/St. LPS has also been shown to bypass tolerant T cells in LPS-sensitive mice late in tolerance to HGG at a time when B cells are responsive. However, in the C3H/HeJ, neither LPS-B nor LPS-P was capable of this function. The responsiveness of these B cells to HGG was demonstrated in transfer experiments. Thus, in the C3H/HeJ, LPS-B stimulates mitogenesis, polyclonal B-cell activation, and inhibition of tolerance induction, but cannot act as an effective adjuvant or as a bypass mechanism to activate B cells in the presence of tolerant T cells. The explanation for this pattern of responses may be attributable to yet another cellular defect in the C3H/HeJ mouse.
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PMID:Immunologic responsiveness of the C3H/HeJ mouse: differential ability of butanol-extracted lipopolysaccharide (LPS) to evoke LPS-mediated effects. 7 41

By the use of phenol water extraction it was possible to obtain strictly serotype-specific antigens from mucoid cell cultures of five serotypes of Haemophilus parahaemolyticus (pleuropneumoniae). These serotype-specific antigens did not cross-react with each other in immunodiffusion tests. The type-specific precipitating phenol-water-fractions were composed of two to four antigenic components, presumably of polysaccharide or lipopolysaccharide nature.
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PMID:Serologic studies on porcine strains of Haemophilus parahaemolyticus (pleuropneumoniae): extraction of type-specific antigens. 9 4

Lipopolysaccharides of eight wild-type strains of the phototrophic bacterium Rhodospirillum tenue have been analyzed. All of the lipopolysaccharides are highly lipophilic. The compositions of preparations obtained by the phenol-water or by the phenol-chloroform-petroleum ether procedure are very similar. The polysaccharide moiety, obtained by mild acid hydrolysis of lipopolysaccharide, consists mainly of aldoheptoses: L-glycero-D-mannoheptose is present in all strains, whereas D-glycero-D-mannoheptose is an additional constituent in some strains. Galactosaminuronic acid and two unknown ninhydrin-positive components were detected in the lipopolysaccharides of six strains. Spermidine and putrescine are present in large amounts in a salt-like linkage in the lipopolysaccharides from three strains. 2-Keto-3-deoxyoctonate forms the linkage between the polysaccharide moiety and lipid A. The lipid A fraction contains all the glucosamine and all the D-arabinose present in the lipopolysaccharide. D-Arabinose is an invariable constituent of the lipid A from the Rhodopseudomonas tenue lipopolysaccharides investigated. The principal fatty acids are beta-hydroxycapric, myristic, and palmitic acids. The isolated R. tenue lipopolysaccharides (O-antigens) react with rabbit antisera prepared against homologous cells. The titers in passive hemagglutination are low, similar to those found with enterobacterial R-lipopolysaccharides. R. tenue O-antigens containing only L-glycero-D-mannoheptose and those containing both the L- and D-epimers of glycero-D-mannoheptose could not be differentiated by serological means.
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PMID:Lipophilic O-antigens in Rhodospirillum tenue. 9 59

A procedure is described for isolating a high-molecular-weight polysaccharide (PS) from the slime of Pseudomonas aeruginosa immunotype 1. The resultant material, obtained from the void volume of a Sephadex G-100 column, was composed of carbohydrate and water. No lipopolysaccharide (LPS), 2-keto-3-deoxyoctonoate, heptose, phosphate, or protein was detectable, and nucleic acid contamination was generally below 1%. The carbohydrate composition of the PS was glucose, rhamnose, galactose, arabinose, and mannose. PS had a molecular weight of between 100,000 and 350,000 and did not disaggregate when chromatographed in the presence of sodium deoxycholate. An antigen immunologically indistinguishable from PS could be obtained from LPS by either acetic acid hydrolysis and column chromatography or by allowing solutions of LPS to stand at room temperature for 3 days. Some of this LPS-associated polysaccharide eluted as the void volume of a G-100 column but differed from PS by its lack of galactose and arabinose. LPS also contained an immunodeterminant not shared with PS that was detected by its stability to dilute alkali treatment (0.1 N NaOH, 37 degrees C, 2 h). PS was destroyed by alkali treatment. PS appeared to represent a form of LPS polysaccharide side chain that contains galactose and arabinose and is of a high molecular weight.
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PMID:Isolation and characterization of a high-molecular-weight polysaccharide from the slime of Pseudomonas aeruginosa. 10 40

The localisation of lipopolysaccharide-binding sites on erythrocytes with peroxidase-coupled LPS is described. LPS was isolated from Fusobacterium nucleatum (Fus MC-8) by phenol-water extraction. The LPS was coupled to horseradish peroxidase by the two-step method of Avrameas and Ternynck (1971). The biological and serological activities of the conjugated LPS were compared with those of the native material. Peroxidase could be coupled to LPS without significant loss of endotoxic or serological activity. The LPS-peroxidase conjugate could be demonstrated on erythrocytes by light and electron microscopy.
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PMID:Ultrastructural localisation of lipopolysaccharide-binding sites with peroxidase-conjugated lipopolysaccharides. 10 40

In an attempt to obtain pure and well characterized smooth lipopolysaccharide (S-LPS) and rough lipopolysaccharide (R-LPS), smooth and rough strains of Brucella abortus were extracted by two different modifications of the phenol-water method. S-LPS was obtained in the phenol phase, and R-LPS was obtained in the aqueous phase. Further purification was accomplished by treatment with enzymes, detergents, NaI as a chaotropic agent to separate non-covalently bound contaminants, and by gel filtration. The degree of purity of the molecules was determined by chemical and immunological analysis and by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Lipid identification by gas-liquid chromatography showed seven major fatty acids. Palmitic acid accounts for about 50%, stearic acid accounts for about 10%, and hydroxylated fatty acids account for less than 5% of total fatty acids. 2-Keto-3-deoxyoctonate but not heptose was detected in the sugar analysis. Protein was found to be firmly bound to S-LPS but not to R-LPS.
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PMID:Purification and characterization of smooth and rough lipopolysaccharides from Brucella abortus. 10 57

The surface topography of whole cells and the chemical composition of cell envelopes of a smooth-intermediate strain (45/0) and a rough strain (45/20) of Brucella abortus was examined. Electron microscopy of whole cells and thin sections did not reveal any gross surface difference(s). Only minor quantitative differences were observed in total lipids, proteins, and the murein layer. However, the lipopolysaccharide composition of the two strains was quite different. Both phenol- and water-soluble lipopolysaccharide fractions were obtained from the strain of higher virulence (45/0), whereas only aqueous lipopolysaccharide could be isolated from the rough strain. In addition to being toxic, the phenol-soluble lipopolysaccharide may be a key virulence factor in intracellular survival of B. obortus within phagocytic cells.
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PMID:Surface macromolecules and virulence in intracellular parasitism: comparison of cell envelope components of smooth and rough strains of Brucella abortus. 11 Jun 83


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