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

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

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

Escherichia coli strain JF694 contains a new major outer membrane protein which we have called protein E (J. Foulds, and T. Chai, J. Bacteriol. 133:1478-1483). Two new bacteriophages, TC45 and TC23, were isolated that require the presence of protein E in the outer membrane of host cells for growth. Both of these bacteriophages have a morphology similar to T-even bacteriophages but are distinct in properties such as plaque morphology, buoyant density, and burst size. Although strain JF694, containing protein E, adsorbs bacteriophage TC45 efficiently, cells killed with heat or chloroform are unable to inactivate this bacteriophage. Purified protein E either in the presence or absence of additional probable cofactors such as lipopolysaccharide was also unable to inactivate bacteriophage TC45. Both bacteriophages probably use protein E as at least part of their receptor but require, in addition, other outer membrane components or a specific orientation or organization of this protein in the outer membrane.
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PMID:Two bacteriophages which utilize a new Escherichia coli major outer membrane protein as part of their receptor. 9 66

Isolation of lipid A by acid hydrolysis of Shigella flexneri lipopolysaccharide resulted in a product that consisted of a heterogeneous mixture of bands when visualized by thin layer chromatography. Differential extraction with ethyl acetate and chloroform, or extraction with EDTA, followed by chloroform-methanol-water (Bligh-Dyer extraction), or a combination of both extraction schemes, resulted in partial purification of immunologically active lipid A. Eight fractions were purified further by preparative thin layer chromatography, and each of the fractions had phosphate, carbohydrate, and esterified fatty acids. Upon incorporation into liposomes, five of the eight purified fractions reacted with anti-lipid A serum, but the three fractions with the most number of esterified fatty acids failed to react with anti-lipid A serum. At least one fraction that originally was unreactive with anti-lipid A serum became reactive as a hapten inhibitor upon removal of esterified fatty acids by alkaline hydrolysis. Alkali-treated fractions from "unreactive" and "reactive" lipid A had similar activities as hapten inhibitors. Our data suggest that lipid A can exist in multiple forms that differ by the number and placement, and possibly by the type, of fatty acids linked to the carbohydrate of lipid A. Highly acylated forms of lipid A do not react with antiserum against the unpurified lipid A mixture, but removal of fatty acids does expose immunoreactive groups.
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PMID:Lipid A from endotoxin: antigenic activities of purified fractions in liposomes. 11 18

1. The lipid fraction extracted from the outer and cytoplasmic membranes of Proteus mirabilis with chloroform/methanol consisted almost entirely of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. 2. The phospholipid content of the cytoplasmic membrane was more than twice that of the outer membrane (38% as against 18% of the total dry weight) and the proportions of the three phospholipids differed somewhat in the two membranes. Yet, the fatty acid composition of the extractable lipids was essentially the same in both membranes. 3. The freedom of motion of spin-labeled fatty acids in the outer membrane of P. mirabilis depended markedly on temperature and on the position of the nitroxide group on the hydrocarbon chain of the probe, suggesting that the local environment of the probe is an associate lipid structure with the properties of a bilayer. Nevertheless, the mobility of the probe was more restricted in the outer membrane than in the cytoplasmic membrane, indicating a higher viscosity of the outer membrane. 4. Chloroform/methanol completely removed the phospholipids from the outer membrane, leaving the lipopolysaccharide moiety intact. The motion of spin-labeled fatty acids in the extracted membranes was, however, highly restricted, suggesting that, in the native outer membrane, the local environment of the probe is composed of phospholipids rather than lipopolysaccharide. Aqueous acetone extraction removed only 75-80% of the phospholipids of the outer membrane. Nevertheless, the mobility of the spin-labeled fatty acid remained highly restricted, suggesting the existence of two phospholipid environments in the outer membrane differing in the nature of their association with the lipopolysaccharide and protein moieties.
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PMID:The outer membrane of Proteus mirabilis. II. The extractable lipid fraction and electron-paramagnetic resonance analysis of the outer and cytoplasmic membranes. 16 15

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

The paper describes the preparation of the lipopolysaccharide from Salmonella abortus equi as obtained by standardized methods. The include the extraction with pehnol/water followed by phenol/chloroform/petroleum ether extraction, ultra-centrifugation, electrodialysis and conversion to the uniform sodium salt form. Chemical composition and physico chemical properties are described. The preparation, which is free from contaminants, was tested for local Shwartzman reactivity, pyrogenicity, lethal toxicity, mitogenicity, reactivity towards complement and tumoricidal action.
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PMID:Preparation and properties of a standardized lipopolysaccharide from salmonella abortus equi (Novo-Pyrexal). 45 65

Lipopolysaccharides from different R mutants of Salmonella minnesota and Salmonella typhimurium belonging to chemotypes Ra to Re, as well as from three SR mutants of Salmonella typhimurium were selected for a study of their precipitability with Concanavalin A. Predictions as to the outcome of the reaction could be made since both the chemical structure of the Salmonella R lipopolysaccharides and structural requirements for a positive reaction with Concanavalin A are well established. Precipitation studies in the immuno-electrophoretic assay and in the microcapillary test were carried out with alkali-treated lipopolysaccharides as untreated lipopolysaccharide is too highly aggregated to allow a sufficient migration in agarose layers. Lipopolysaccharides of all mutants--except the SR mutants--were obtained by the phenol/chloroform/petroleum ether method in order to avoid contaminations by glucans or glycogen which are known to occur in phenol/water extracted lipopolysaccharides and which would lead to erroneous results. Additional precipitation studies were carried out with two other lectins of different polysaccharide specificity: Wheat Germ Agglutinin and Soybean Agglutinin. As expected, lipopolysaccharides of chemotypes Ra, Rb1, and RcP- mutants reacted strongly with Concanavalin A, whereas no reaction was demonstrable with lipopolysaccharides of chemotypes Rb2, Rb3, Rd and Re mutants. The lipopolysaccharide of an RcP+ mutant unexpectedly failed to precipitate unless it was dephosphorylated with HF. This artificially prepared RcP-lipopolysaccharide showed a strong reaction, thus demonstrating that negative charges in the direct neighborhood of reactive sugar units as in RcP+ LPS may prevent precipitation with Concanavalin A. No reactivity demonstrable by precipitation could be obtained using either Wheat Germ Agglutinin or Soybean Agglutinin with alkali-treated lipopolysaccharide even of those chemotypes which had the supposedly reactive sugar in a terminal position, such as N-acetyl-D-glucosamine in Ra mutants (Wheat Germ Agglutinin) or D-galactose in Rb2 or Rb3 mutants (Soybean Agglutinin).
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PMID:Reactivity of lipopolysaccharides from various salmonella SR and R chemotypes Ra-Re mutants with concanavalin A. 76 3

A total of six mutants, to which phage epsilon could adsorb but failed to lyse, were isolated from Salmonella anatum and characterized. A significant portion of active phage particles could be recovered from the phage-bacterium complexes before they became irreversibly absorbed, and adsorbed phage did not kill these mutants at all. These reversibly adsorbed phage had become sensitive to chloroform, at least in some cases. The results indicate that the steps that may be blocked are deoxyribonucleic acid ejection or penetration. The mutants were tentatively classified into three groups by their susceptibility to phages c341 and Felix O. The inhibition of phage infection was overcome by host range mutants of phages epsilon and c341. The isolated lipopolysaccharide from the parent strain inactivated phages epsilon, c341, and a host range mutant of epsilon in vitro. However, neither phage epsilon nor c341, or the host range mutant of phage epsilon, was inactivated by incubation with the mutant lipopolysaccharides, even when they were derived from the mutants susceptible to c341 or the host range mutant of epsilon. These results may suggest that more than the receptor lipopolysaccharide of the bacterial surface is involved in the early stages of phage infection.
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PMID:Mutants of Salmonella anatum that block bacteriophage epsilon infection at early stages. 93 54

Bacterial lipopolysaccharides extracted from Bacteroides fragilis subspecies fragilis lacked 2-keto-3-deoxyoctonate and heptose, sugars which make up part of the inner core of most bacterial endotoxins. Over 98% of the lipid portion of this material could be removed easily with chloroform-methanol and alcohol, a finding which indicates a loose association between the polysaccharide and lipid moieties. The lipopolysaccharides caused gelation of limulus lysate at a concentration significantly higher than that for the endotoxin of Salmonella typhi. None of the extracts was lethal in 10-day-old chick embryos at doses of greater than 200 mug per egg, whereas the endotoxin of Neisseria meningitidis was lethal at a dose of 1.2 mug per egg. The local Shwartzman reaction could not be induced by levels of B. fragilis endotoxin of up to 1,000 mug per rabbit, whereas a (control) endotoxin of S. typhi induced this phenomenon at a level of 3 mug per rabbit. Intact oxygen-killed B. fragilis failed to provoke the local Shwartzman reaction at doses of 2,500 mug. These results indicate that B. fragilis has a lipopolysaccharide different from that of most gram-negative bacteria. Although it retains some of the chemical and biologic properties of classical endotoxin, it seems to lack others. This observation may have significant clinical implications.
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PMID:Chemical and biological characterization of the lipopolysaccharide of Bacteroides fragilis subspecies fragilis. 93 22


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