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

The O-specific polysaccharide obtained from the lipopolysaccharide of Shigella dysenteriae type 1 (Shigella shiga) by mild acid hydrolysis followed by fractionation on Sephadex G-50 was found to be identical to that desribed by Morgan's group and was composed of L-rhamnose, D-galactose and N-acetyl-D-glycosamine in a ratio 2:1:1. On the basis of methylation analysis data the polysaccharide was proved to be a linear chain of monosaccharide residues in pyranose forms substituted at position 3, except for that of galactose substituted at position 2. Selective cleavage, based on the N-deacetylation reaction of the polymer, together with determination of linkage configurations by chromic anhydride oxidation showed that the O-specific polysaccharide is built up of repeating tetrasaccharide units whose proposed structure is given below -3)-alpha-L-Rhap (1-3)-alpha-L-Rhap(1-2)-alpha-D-Galp(1-3)-alphapD-GlcNAcp(1- where RHAP = rhamnopyranose, Galp = galactopyranose, and GlcNAcp = N-acetyl-glucosamine. The present findings confirmed the considerations of Heidelberger on the substitution patterns of L-rhamnose and D-galactose residues from the results of serological studies.
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PMID:Somatic antigens of shigella. Structural investigation on the O-specific polysaccharide chain of Shigella dysenteriae type 1 lipopolysaccharide. 0 14

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

One the cell surface of smooth of Yersinia enterocolitica 75 (Ye 75 S), and electron-lucent layer was identified in thin sections after incubation with Ye 75 S-antiserum. It is adjacent to the "double track" of the outer membrane. This layer does not appear on the analogously treated rough mutant (Ye 75 R), whose lipopolysaccharide (LPS) does not contain O-specific polysaccharides. It could be shown that this layer is formed by the O-specific side chains of LPS, which are unstained by routine methods. As the side chains of LPS obviosly make it difficult to visualize the LPS-strands in the outer membrane of rough strands was investigated. On Ye 75 R, the LPS-strands could be demonstrated only after treatment of cells with polymyxin B. After short time of exposure, the LPS appeared as contigous strand-like structures (diameter roughly 60 A) on the cell surface of cells which were negatively stained or dried by the critical-point-method. After prolonging polymyxin B treatment, "blebs" or "protrusions" appeared on the surface of Ye 75 cells, which were in negatively stained preparations and in thin sections identified as partly loosened LPS. The demonstration of LPS-strands in untreated cells was possible only on a "deep rough" mutant (Ye 161-45 a R), whose LPS contains only glucosamine and KDO besides lipid A. It is suggested that the LPS form a layer of contiguous strands (mid-to-distance 62 +/- 3 A) on the surface of negatively stained cells. According to this view, on the Ye 75 S, the O-specific side chains extend from this layer into the medium.
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PMID:The arrangement of lipopolysaccharides on the outer membrane of Yersinia enterocolitica: an electron microscopic study. 6 41

Rabbits were immunized with Salmonella minnesota Re mutant bacilli or lipid A, and the serological responses were compared. Re lipopolysaccharide and lipid A were found to possess distinct antigenic determinants as measured by hemagglutination, hemolysis, and precipitin techniques. Lipid A preparations from several enterobacterial and non-enterobacterial species were shown to cross-react in agar gel precipitation reactions. In contrast, preparations from bacilli that do not contain glucosamine as an integral part of their lipid A structure did not demonstrate cross-reactivity with enterobacterial lipid A. Antibody to smooth heterologous bacilli present in some antisera prepared against Re bacilli or lipid A was directed specifically against the smooth lipopolysaccharide and not against the Re or lipid A determinants, demonstrating a nonspecific mitogenic response. Precipitation and immunofluorescence tests indicated that the Re determinant was available on smooth bacilli for reactions with specific antisera but that the lipid A determinant was not.
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PMID:Immunization with R mutants of Salmonella minnesota. II. Serological response to lipid A and the lipopolysaccharide of Re mutants. 6 13

An extract made from the supernatant of Neisseria gonorrhoeae Gc2 strain 1291 degraded the Gc2 polysaccharide antigen. Chemical analysis of this polysaccharide indicated it contains glucose, galactose, glucosamine, galactosamine, glucosamine-6-phosphate, heptose, 2-keto-3-deoxyotonate, and ethanolamine and is the polysaccharide component of gonococcal lipopolysaccharide. Degradation of the polysaccharide by sonic extracts resulted either in complete loss of antigenicity and immunogenicity or in partial degradation to subunits that could inhibit the Gc2-specific hemagglutination inhibition. The factors responsible for degradation were destroyed by heating at 100 degrees C for 5 min or by Pronase digestion, but were unaffected by ribonuclease, deoxyribonuclease, Mg2+, Ca2+, or ethylenediaminetetraacetic acid. The process was pH dependent, with optimal activity occurring at pH 7. Sonic extract supernatants from group B and C meningococcal strains contained degrading properties, whereas similar extracts produced from Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Streptococcus pneumoniae type II failed to degrade the Gc2 polysaccharide.
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PMID:Degradation of the polysaccharide component of gonococcal lipopolysaccharide by gonococcal and meningococcal sonic extracts. 7 94

Three immunologically distinct types of polysaccharides have been isolated by diethylaminoethyl (DEAE) chromatography from the lipopolysaccharide extracts of group B Neisseria meningitidis. All types contain a set of common determinants, as well as distinct ones; all of these determinants are detectable by either immunodiffusion or enzyme-linked immunosorbent assay (ELISA). The polysaccharides elute from a Sepharose 4B column in the range of 2-3 x 10(5) daltons and have isoelectric points from 4.2 to 4.3. Their antigenicity is destroyed by oxidation but is unaffected by neuraminidase, lysozyme, or trypsin. One type of polysaccharide cross-reacts with the Gc2 polysaccharide of Neisseria gonorrhoeae in immunodiffusion systems. Chemical analysis indicates that these polysaccharides contain hexoses, hexosamines, 2-keto-3-deoxyoctonate, ethanolamine, and heptose; analysis of amino acids indicates protein contents of less than 0.05%. In contrast to the lipopolysaccharide from which they are derived, these polysaccharides contain no lipid A and less than 0.5% fatty acids. All three types are precipitated by wheat germ agglutinin but not by concanavalin A or fucose-binding protein. Specific inhibition of this precipitation can be achieved with N-acetyl glucosamine. These antigens may be the bases of a lipopolysaccharide-derived typing system for group B N. meningitidis.
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PMID:Lipopolysaccharide-derived serotype polysaccharides from Neisseria meningitidis group B. 8 91

Lipid A isolated from lipopolysaccharide of Yersinia pseudotuberculosis was used for immunization of rabbits to afford antisera to lipid A with titers of 1:640 in the passive hemolysis test. Exhaustion of immune serume with sheep erythrocytes decreased antibody titers up to 1:160. Authentic samples of 2-(DL-3-hydroxytetradecanoyl)amino-2-deoxy-D-glucose 6-phosphate, 2-tetradecanoylamino-2-deoxy-D-glucose 6-phosphate and 2-acetamido-2-deoxy-D-glucose 6-phosphate have been synthesized in order to carry out a comparative study of inhibitory activity of these compounds and lipid A using a system of lipid A and antiserum to lipid A. As a result, the immunodominant moiety of the lipid A of Y. pseudotuberculosis proved to contain a D-glucosamine residue acylated with 3-hydroxytetradecanoic acid at the amino group. The nature of the fatty acid acylating the amino group of glucosamine does not play an important role in the structure of immunodominant moiety of lipid A.
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PMID:Structural studies on the immunodominant group of lipid A from lipopolysaccharide of Yersinia pseudotuberculosis. 8 32

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

The presence of two distinct lipopolysaccharides in Yersinia enterocolitica O:9 is described: one isolated from the aqueous phase and one from the phenol phase (Westphal system). The sugar moiety of the phenol phase lipopolysaccharide has been identified as being responsible for the serologic cross-reaction of Y. enterocolitica O:9, Brucella abortus and Vibrio cholerae. The phenol phase antigen consists of glucose, galactose, glucosamine, 2-keto-3-deoxyoctonic acid, heptose, lipid A and a protein moiety. Haemagglutination experiments revealed two different structures: one that readily coats erythrocytes and another that requires alkali treatment. The former may be separated by repeated adsorptions on erythrocytes. Serologically, the two structures behave like a single antigen. The action of normal rabbit serum on the erythrocyte-containg capacity of the two structures was studied.
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PMID:Immunochemical studies on a Yersinia enterocolitica O:9 lipopolysaccharide cross-reacting with Brucella abortus and Vibrio cholerae extracts. 10 56

The effect of benzylpenicillin on the synthesis and morphology of the cell envelope of Neisseria gonorrhoeae was examined. Penicillin immediately stopped murein synthesis; it also enhanced the rate of turnover of glucosamine, but not diaminopimelic acid, in the murein. In addition, penicillin greatly increased the shedding of lipid and lipopolysaccharide into the medium. In the electron microscope, protrusions of the cell membrane were evident, as well as apparent holes in the murein cell wall. All of these changes occurred while active synthesis was taking place, before the lysis of the cells. Lysis could be prevented by growing the cells at low pH and high concentrations of Mg2+; however, the effects of penicillin on murein synthesis and turnover and on the release of lipid were not affected.
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PMID:Effect of benzylpenicillin on the synthesis and structure of the cell envelope of Neisseria gonorrhoeae. 12 27


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