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

Gonorrhea has been known since antiquity. Today, this disease is the most commonly reported infectious disease in the U.S. The natural environment of the etiological agent, Neisseria gonorrhoeae, is man. In this host, the organism usually parasitizes mucosal surfaces populated by columnar epithelial cells. Under certain conditions, the gonococcus may disseminate or spread to adjacent organs. The gonococcus is well adapted to its environment and is a successful parasite. Until recently, gonococci were uniformly sensitive to penicilin. However, a plasmid encoding beta-lactamase has been identified in some isolates. Most strains exhibit specific requirements for various amino acids, vitamins, purines, and pyrimidines. Only glucose, pyruvate, and lactate are utilized as sources of energy. Glucose is dissimilated by a combination of the Entner-Doudoroff and pentose phosphate pathways. A tricarboxylic acid cycle is also present and active under certain conditions. Structurally, the cell envelope of the gonococcus resembles that of a typical Gram-negative bacterium. Gonococci are highly autolytic, especially in older cultures or after depletion of the energy source. Autolysis is not due solely to peptidoglycan hydrolysis, but appears to involve a destabilization of the outer membrane as well. Cell surface components such as pili, lipopolysaccharide, outer membrane proteins, and a capsule are associated with the virulence and pathogenicity of this organism.
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PMID:The biology of the gonococcus. 11 74

Wall fragments were prepared from two strains of Pseudomonas cepacia and from P. aeruginosa, and their contents of readily extractable lipid, pronase-digestible protein and lipopolysaccharide were measured. Lipopolysaccharide extracted from P. cepacia, although biologically active, contained no detectable 2-keto-3-deoxyoctonic acid, but contained phosphate, rhamnose, glucose, heptose and hexosamine in concentrations comparable to those found in P. aeruginosa.
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PMID:Isolation of atypical lipopolysaccharides from purified cell walls of Pseudomonas cepacia. 11 93

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

Bacterial lipopolysaccharides are negatively charged macromolecules due to the presence of phosphate, pyrophosphate and carboxyl groups. When isolated from bacteria, they are obtained in salt form with metal cations and basic amines. Removal of these ionically bound substances by electrodialysis leads to acidic lipopolysaccharides which on neutralizing with different bases, preparations are obtained which show distinct differences in their physico-chemical properties and in their biological activity. Soluble lipopolysaccharides interact with complement leading to loss of hemolytic activity. This property is embedded in the lipid A part of the molecule and is expressed only when the lipopolysaccharide is present in a favourable particle size. Nevertheless, a number of lipopolysaccharides exists, which, regardless of their particle size do not interact with complement. Lipid A is the part of the molecule responsible for endotoxicity. This was demonstrated by employing solubilized lipid A in complex form with BSA. Soluble lipid A/BSA complexes proved highly toxic for mice and pyrogenic in rabbits, and express many biological activities exhibited by intact lipopolysaccharides. Lipid A, when exposed on the bacterial cell-surface acts as a powerful immunogen, giving rise to the production of specific anti-lipid A antibodies that interact with the lipid A obtained from lipopolysaccharides that are otherwise distinct in their O-serological specificity. Anti-lipid A antibodies occur naturally in the serum of many animals and humans. The biological significance of anti-lipid A antibodies is discussed.
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PMID:Physical state and biological activity of lipopolysaccharides. Toxicity and immunogenicity of the lipid A component. 12 55

Membrane vesicles were prepared from Azotobacter vinelandii spheroplasts by lysis in either potassium phosphate (pH 7.0) or Tris1-acetate (pH 7.8) buffers. These 2 types of preparations differ considerably in their properties: 1) Examination by scanning electron microscopy reveals that the Pi vesicles consist primarily of closed structures 0.6-0.8 micrometer in diameter with a rough or particulate surface similar to that of spheroplasts. The Tris vesicles are significantly smaller, 0.1-0.3 micrometer in diameter, and have a much smoother surface structure. 2) Antisera from rabbits immunized with A. vinelandii lipopolysaccharide antigen will agglutinate Pi vesicles but not Tris vesicles. 3) Tris vesicles have a fourfold higher specific activity of latent H+-ATPase than Pi vesicles. After exposure to Triton X-100 similar ATPase activities are observed for both types of vesicles. 4) Pi vesicles transport calcium in the presence of ATP or lactate at less than 30% of the rats observed for Tris vesicles. 5) Tris vesicles have less than 22% of the transport capacity of Pi vesicles for accumulation of labeled sucrose and less than 3% of the capacity for valinomycin-induced uptake of rubidium observed during respiration. 6) Quinacrine fluorescence intensity is reduced by 30% during lactate oxidation and 20% during ATP hydrolysis by Tris vesicles. Under similar conditions, fluorescence in Pi vesicles is quenched by only 7% and less than 2%, respectively. These findings suggest that Pi vesicles have the normal orientation of the intact cell whereas Tris vesicles have an inverted topology.
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PMID:Isolation of membrane vesicles with inverted topology by osmotic lysis of Azotobacter vinelandii spheroplasts. 14 14

Electron micrographs of lipopolysaccharide (LPS) from Serratia marcescens which have been extracted with phenol/water, suspended in dist. water and subsequently negatively stained reveale round to ovoid particles besides singular ribbon-like structures. These structures are interpreted as collapsed LPS-strands of the outer membrane (OM). Fine structure investigations were carried out on strand-like structures which had been obtained by light alcalization of the particle suspension. Partial denaturation of LPS in ethylene-diaminotetracetic acid with polymyxin B (PB) gave rise to broad bends with periodic 180 degrees-torsions, indicating a helical structure. Chemically fixed LPS in phosphate buffer which were only partial transformed into LPS-strands, additionally revealed that a given LPS-strand consists of two electron-microscopic identical sub-strands which form a double helix. After short times of exposure to PB, negatively stained cells of Serratia marcescens show strand-like cell wall components on the cell surface consisting of longitudinal fibrils. In a further stage of denaturation, the strand-like structures form "projections" of the OM or are completely loosened. Based on a helical arrangement in the negative staining preparations as well as in the thin sections, they are identified as LPS-strands. Presumably, the LPS in the OM exists as contiguous strains. The development of the "double track"-aspect of the LPS in thin sections may be explained as a result of the projections of the helical longitudinal fibrils into the image plane.
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PMID:[Ultrastructural study of lipopolysaccharide and of polymyxin B-induced changes of the outer membrane of Serratia marcescens (author's transl)]. 20 Nov 29

The structure of lipopolysaccharide from a heptose-less mutant of Escherichia coli K-12 has been investigated. Lipopolysaccharide isolated from 32P-labeled cells was treated with mild alkali to yield two separable components: [OH-LPS]-I (approximately 70%) and [OH-LPS]-II (approximately 30%). Mild acidic treatment of [OH-LPS]-I gave mainly a product which was identified as (4-O-phosphoryl-N-beta-hydroxymyristyl-D-glucosaminyl)-beta(1 leads to 6)-N-beta-hydroxymyristyl-D-glucosamine 1-phosphate (Compound I). Further acidic hydrolysis of both [OH-LPS]-I and [OH-LPS]-II yielded as the main product (4-O-phosphoryl-N-beta-hydroxymyristyl-D-glucosaminyl)-beta(1 leads to 6)-N-beta-hydroxymyristyl-D-glucosamine (Compound II). The structures of the above products were deduced by a combination of compositional analyses, sensitivity to phosphomonoesterase, rates of hydrolysis of the phosphate groups and alkali-catalyzed beta elimination of the phosphate residues following appropriate oxidation of hydroxyl groups. These studies together with work reported in the accompanying papers have led to the identification of two species of lipopolysaccharide in the E. coli strain both of which contain a single glucosamine dissacharide unit but differ in having monosubstituted phosphate or pyrophosphate groups at the glycosidic position. Each species of lipopolysaccharide also appeared to be heterogeneous with respect to the number of esterified fatty acyl groups.
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PMID:Structure of the lipopolysaccharide from an Escherichia coli heptose-less mutant. I. Chemical degradations and identification of products. 22 86

Endotoxin was shown to depress neutrophil bactericidal activity while enhancing Nitro Blue Tetrazolium reduction and hexose monophosphate shunt activity. Separation of bactericidal action from oxidative metabolism suggests that the effect of endotoxin might involve the formation of reactive oxygen radicals such as superoxide. Chemiluminescence often accompanies metabolic activation of polymorphonuclear neutrophils (PMNs). However, human PMNs did not show chemiluminescence when challenged with endotoxin (lipopolysaccharide; LPS) or lipid A. Superoxide formation was also unaffected by endotoxin. In contrast, preincubation of PMNs with LPS for 30 min produced significant depression of chemiluminescence, oxygen consumption, and superoxide formation. Decreased chemiluminescence was not the result of complement consumption. In a cell-free system, superoxide was not scavenged by LPS, nor did LPS stimulate superoxide dismutase. Oxidase enzymes for reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate harvested from broken cells were not affected by LPS. The toxicity of LPS may reside in its ability to activate the PMNs while simultaneously blocking bactericidal capacity.
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PMID:Endotoxin in vitro interactions with human neutrophils: depression of chemiluminescence, oxygen consumption, superoxide production, and killing. 22 88

Lipopolysaccharide from strains of Haemophilus influenzae was extracted and isolated by the hot phenol-water procedure. The preparations were relatively insoluble in water but could be solubilized with surface-active agents. The preparations contained carbohydrate (30%), fatty acid (29%), and phosphate (4.7%); protein content was less than 1%. Thin-layer chromatography, gas-liquid chromatography, and colorimetric assays detected glucose, galactose, glucosamine, heptose, and a 2-keto-3-deoxy-octonate-like molecule (less than 1%). Neither methylpentose nor dideoxyhexose was detected. The lipid portion was composed of fatty acids common to lipopolysaccharide of Salmonella. The preparations provoked positive dermal Shwartzman reactions and biphasic febrile responses in rabbits, responses typical of endotoxic activity. The 50% lethal dose for mice was decreased from 16.5 microgram/g to 0.015 microgram/g by concomitant administration of actinomycin D. The preparations were shown to be polyclonal activators of bone marrow-derived (B) cells. Limulus lysate gelation was seen with 8.0 ng of lipopolysaccharide. Preliminary hemagglutination data suggested at least three different antigenic factors associated with the lipopolysaccharide of H. influenzae type b. The H. influenzae lipopolysaccharide appeared biologically similar to that of enterobacteria but chemically different.
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PMID:Characterization of lipopolysaccharide of Haemophilus influenzae. 31 Aug 55

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.
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PMID:Ribitol-containing lipopolysaccharides from Proteus mirabilis and their serological relationship. 31 1


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