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

Exopolysaccharides interfere with the isolation and characterization of plasmid DNA from gram-negative bacteria. To repress capsular polysaccharide production, bacteria were cultured in medium containing bismuth nitrate and sodium salicylate. Rapid removal of other contaminating bacterial surface components was achieved by mild acidic zwitterionic detergent extraction. After treatment, bacterial cells were more readily lysed in alkaline detergents. The resulting plasmid preparations contained virtually no capsular polysaccharide and relatively small quantities of lipopolysaccharide and protein, yet they produced yields of nucleic acids similar to those of conventional plasmid preparations. Conventional preparations from encapsulated organisms were largely insoluble and appeared as smears following agarose gel electrophoresis, with indefinite plasmid banding. Plasmids prepared by the new method were highly soluble in conventional buffers and exhibited high-resolution plasmid banding patterns in agarose gels. Plasmids as large as 180 kbp could be isolated and visualized, without apparent nicking, and were readily digested by restriction endonuclease enzymes. The method proved effective with encapsulated or mucoid strains of Klebsiella pneumoniae, Escherichia coli, Acinetobacter anitratus, Salmonella typhimurium, and Enterobacter species. The complete method for plasmid isolation was not suitable for Pseudomonas aeruginosa because of the inhibitory effects of bismuth. Thus, removal of contaminating bacterial surface structures enabled the rapid isolation and characterization of plasmids from mucoid clinical isolates, without the use of organic solvents, CsCl gradients, or expensive, disposable columns.
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PMID:Rapid plasmid DNA isolation from mucoid gram-negative bacteria. 133 82

Cytochrome oxidase variants of the bacterial fish pathogen, Aeromonas salmonicida, were characterized for genetic and molecular homology with cytochrome oxidase-positive isolates that typically induce furunculosis in salmonids. Protein and lipopolysaccharide moieties of the cytochrome oxidase-negative variants were similar to their typical counterparts, based on sodium-dodecyl-sulfate polyacrylamide gel electrophoresis. Pathogenicity of aberrant isolates to brook trout (Salvelinus fontinalis) was similar to typical cytochrome oxidase-positive isolates. Colorimetric deoxyribonucleic acid (DNA) hybridization in 96-well microplates yielded homology values greater than 82.5% for typical aberrant A. salmonicida isolates when photobiotinylated DNA for reference A. salmonicida 3.101 was used as a probe. The only variation of these isolates from typical A. salmonicida was a negative cytochrome oxidase reaction.
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PMID:Molecular and genetic characterization of cytochrome oxidase-negative Aeromonas salmonicida isolated from coho salmon (Oncorhynchus kisutch). 133 20

Agents that can arrest cellular proliferation are now providing insights into mechanisms of growth factor action and how this action may be controlled. It is shown here that the macrophage activating agents tumor necrosis factor-alpha (TNF alpha), interferon-gamma (IFN gamma), and lipopolysaccharide (LPS) can maximally inhibit colony stimulating factor-1 (CSF-1)-induced, murine bone marrow-derived macrophage (BMM) DNA synthesis even when added 8-12 h after the growth factor, a period coinciding with the G1/S-phase border of the BMM cell cycle. This inhibition was independent of autocrine PGE2 production or increased cAMP levels. In order to compare the mode of action of these agents, their effects on a number of other BMM responses in the absence or presence of CSF-1 were examined. All three agents stimulated BMM protein synthesis; TNF alpha and LPS, but not IFN gamma, stimulated BMM Na+/H+ exchange and Na+,K(+)-ATPase activities, as well as c-fos mRNA levels. IFN gamma did not inhibit the CSF-1-induced Na+,K(+)-ATPase activity. TNF alpha and LPS inhibited both CSF-1-stimulated urokinase-type plasminogen activator (u-PA) mRNA levels and u-PA activity in BMM, whereas IFN gamma lowered only the u-PA activity. In contrast, LPS and IFN gamma, but not TNF alpha, inhibited CSF-1-induced BMM c-myc mRNA levels, the lack of effect of TNF alpha dissociating the inhibition of DNA synthesis and decreased c-myc mRNA expression for this cytokine. These results indicate that certain biochemical responses are common to both growth factors and inhibitors of BMM DNA synthesis and that TNF alpha, IFN gamma, and LPS, even though they all have a common action in suppressing DNA synthesis, activate multiple signaling pathways in BMM, only some of which overlap or converge.
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PMID:Biochemical events accompanying macrophage activation and the inhibition of colony-stimulating factor-1-induced macrophage proliferation by tumor necrosis factor-alpha, interferon-gamma, and lipopolysaccharide. 133 37

In an effort to define the heat shock response in the bovine intracellular pathogen Brucella abortus, a rough variant lacking extensive lipopolysaccharide was pulse-labeled with [35S]methionine following exposure to elevated temperatures. The major heat shock proteins observed following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography migrate at 70, 62, 18, and 10 kDa. The maximum response was observed between 42 and 46 degrees C and within 2 to 3 h of the shif in temperature and varied slightly for the different proteins. Accumulation of the 62-kDa heat shock protein (62-kDa Hsp) was observed to continue for up to 5 h following the shift in temperature. In an effort to better define the heat shock response and its potential relationship with protective immunity, genes encoding the major heat shock proteins were isolated from recombinant libraries constructed from B. abortus S19 and S2308 and sequenced. The 62-kDa Hsp shares more than 60% amino acid homology with members of the GroEL family and is immunoprecipitated with polyclonal antibodies to Escherichia coli GroEL and monoclonal antibodies to mycobacterial Hsp 65. Western blot (immunoblot) analysis with pooled sera from vaccinated and infected cattle revealed that the 62-kDa Hsp is a predominantly recognized antigen. The roles of these gene products during environmental stress and in protective immunity against brucellosis are under investigation.
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PMID:Characterization of the heat shock response in Brucella abortus and isolation of the genes encoding the GroE heat shock proteins. 135 Feb 74

The role of the length of the O-antigen polysaccharide side chain of bacterial lipopolysaccharide (LPS) in biological and model membrane systems was investigated. LPS from Salmonella typhimurium ATCC 14028 was chromatographed on a Sephadex G-200 column in the presence of sodium deoxycholate and separated into three fractions on the basis of molecular size. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blot (immunoblot), and chemical analyses indicated that these fractions differed from each other primarily in the number of repeating units in the O-antigen polysaccharide side chain. In a biological system fractions 2 and 3 had the same effects to induce mitogenesis in murine lymphocytes, but fraction 1 was less effective than the other two fractions. In a model membrane system, LPS induced changes in small unilamellar vesicles (SUVs) which were measured by changes in the behavior of a fluorescent probe, 1,6-diphenylhexa-1,3,5-triene (DPH), and interaction of increasing amounts of all LPS fractions with SUVs gradually increased DPH anisotropy. Fractions 2 and 3 had similar effects on the SUVs as detected by changes in DPH anisotropy, while fraction 1 had almost twice as much activity as the other two fractions. These results suggest that the polysaccharide side chain of LPS may modulate the ability of biologically active lipid A to interact with cells and model membranes. In addition, factors other than changes in membrane fluidity may play a role in mediating LPS-induced cell activation.
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PMID:Characterization of lipopolysaccharide fractions and their interactions with cells and model membranes. 137 Feb 86

Previous research in this laboratory, using photoactivatable radioiodinated lipopolysaccharide derivatized with sulfosuccinimidyl-2-(p-azidosalicylamide)-1,3'-dithiopropionate (125I-ASD-LPS), has resulted in the identification of a specific LPS receptor with a molecular mass of approximately 73 kDa on murine lymphocytes and splenic macrophages. The experiments presented in this report investigated whether a similar LPS-binding protein was also expressed on human peripheral blood populations, including monocytes, lymphocytes, neutrophils, platelets, and erythrocytes. Each cell population was incubated with 125I-ASD-LPS, UV irradiated, washed, reduced, and solubilized, and the cell lysates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. On all of the cell populations, except erythrocytes, a similar 73-kDa LPS-binding protein was present. In addition, each population also expressed lower-molecular-weight secondary LPS-binding proteins, some of which were conserved among the populations. Binding of the photoactivatable LPS probe was found to be both time and temperature dependent. These data support the concept that the 73-kDa LPS-binding protein is conserved on multiple cell types from a variety of species.
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PMID:Identification and characterization of lipopolysaccharide-binding proteins on human peripheral blood cell populations. 137 70

Serotypes O2, O5, and O16 of Pseudomonas aeruginosa are chemically related, and the O antigens of their lipopolysaccharides share a similar trisaccharide repeat backbone structure. Serotype-specific monoclonal antibodies (MAbs) MF71-3, MF15-4, and MF47-4 against the O2, O5, and O16 serotypes, respectively, were isolated. MAb 18-19, which is cross-reactive with all strains of this chemically related serogroup, was also produced. When column chromatography or sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated lipopolysaccharide (LPS) samples from each of the serotypes were probed with the MAbs in Western immunoblots, each of the serotype-specific MAbs interacted only with high-molecular-weight bands of the homologous LPS, with a minimum O-antigen chain length of at least 6 to 10 repeats. In contrast, cross-reactive MAb 18-19 was shown to interact in Western immunoblots with the entire LPS banding pattern except the fastest-running band, which lacks O antigen. Chemical modification of P. aeruginosa LPS by alkali treatment and carboxyl reduction abolished reactions between LPS and MAb 18-19, while reactions of modified LPS with serotype-specific MAbs were not affected. Therefore, cross-reactive MAb 18-19 likely recognizes the chemical backbone structure of the O repeat that is common to all three serotypes of the O2-O5-O16 group, while the O-specific MAbs appeared to recognize LPS epitopes that could be presented when 6 to 10 or more O-antigen repeat units are present on the LPS molecule. Thus, the O-specific LPS epitopes likely involve unique chemical structures, glycosidic linkages, and some order of folding of the O side chains.
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PMID:Monoclonal antibodies as probes to examine serotype-specific and cross-reactive epitopes of lipopolysaccharides from serotypes O2, O5, and O16 of Pseudomonas aeruginosa. 137 99

The ability of Bdellovibrio bacteriovorus to relocalize the OmpF major outer membrane porins from its Escherichia coli prey to its own outer membranes is diminished in prey expressing smooth lipopolysaccharide (S-LPS). Since porins exist in the membrane complexed with LPS, we examined the LPS associated with relocalized porin to determine whether it had been acquired intact, mixed or replaced with Bdellovibrio LPS, or derivatized by the bdellovibrios. The relocalized trimers were found associated with the same LPS originally bound to them in the E. coli. The bulk-phase LPS from bdellovibrios grown on various chemotypes of rough prey was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine whether more than the trimer-bound LPS was acquired by the bdellovibrios. This analysis revealed bands of Bdellovibrio LPS matching the LPS chemotype of the prey. One or two other bands were identical in migration to the LPS of prey-independent mutants of B. bacteriovorus and represented bdellovibrio-synthesized LPS. The LPS of bdellovibrios grown on prey with radiolabeled lipid A showed radioactivity only in gel band positions identical with those of the prey's LPS. The amount of this prey-derived LPS was shown by enzyme-linked immunosorbent assay to reach a constant value during the purification of the bdellovibrios, and it represented approximately 25% of the total Bdellovibrio LPS. Immunoelectron microscopy confirmed the presence of prey-derived LPS on the cell surface of bdellovibrios, and no evidence could be found for bdellovibrio-induced modifications of the relocalized prey LPS.
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PMID:Acquisition of apparently intact and unmodified lipopolysaccharides from Escherichia coli by Bdellovibrio bacteriovorus. 137 16

Two IgG3 murine monoclonal antibodies, Cl-1 and Cl-2, that showed serologic specificities for the O antigens of serogroup C1 (0:6,7) Salmonella were established. The epitopes for the antibodies were found to reside on the repeating units of the serogroup C1 Salmonella lipopolysaccharide and were labile to sodium metaperiodate oxidation. Serologic reactivities of Cl-1 and Cl-2 were not inhibited by commercial monospecific antiserum to O antigen 7, but were inhibited to various degrees by anti-[O:6,7] serum. Both antibodies reacted strongly with all strains of serogroup C1 Salmonella that have either O:6(1),7, O:6(2),7, or O:6(1,2),7 antigens. Reactivities of Cl-1 and Cl-2 with the phage-14 lysogenized C1 strains that bear the phage-modified O antigen (O:6,7----O:6,7,14) were detected by slide agglutination method only and not by whole-cell enzyme-linked immunosorbent assay. Both Cl-1 and Cl-2 antibodies did not react with other O serogroups of salmonellae, nor with other Gram-negative or Gram-positive bacteria. The diagnostic value of these monoclonal antibodies together with a previously described monoclonal antibody against the serogroup C2 Salmonella was demonstrated using the slide agglutination method with monoclonal antibodies ascitic fluids.
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PMID:Characterization and specificity controls of murine monoclonal antibodies against serogroup C1 Salmonella. 137 96

Two structurally and immunologically different components of Bordetella pertussis endotoxin can be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining: a major A band and a faster-migrating minor B band. Certain mutant strains of B. pertussis express only the B band, while the wild-type strains produce both lipooligosaccharides (LOS). Two monoclonal antibodies (MAbs) directed against the minor LOS B band were generated, allowing the study of this surface molecule on different strains of Bordetella. These two MAbs, designated BL-8 and BL-9, reacted strongly with phenol-water-purified LOS obtained from a B. pertussis LOS B mutant strain. Sodium periodate treatment of the purified LOS prevented binding of the MAbs, indicating the carbohydrate nature of the epitope(s). Western immunoblotting experiments revealed that the epitope(s) recognized by these MAbs is conserved on all B. pertussis and Bordetella bronchiseptica Vir- (avirulent) variant strains tested but is not present on Bordetella parapertussis and B. bronchiseptica Vir+ (virulent) wild-type strains. Further studies showed that although present in the lipopolysaccharide B band expressed by Vir- strains, the epitope(s) recognized by the MAbs is not accessible on the surface of intact B. bronchiseptica cells. For B. pertussis, the density and accessibility of this epitope(s) are dependent on the virulence-associated or LOS phenotype expressed by the strain. Our data demonstrate that the expression and accessibility of the epitope(s) are significantly greater on the LOS B variant strains and LOS AB Vir- strains compared with fresh B. pertussis clinical isolates. For these latter strains, which are Vir+, this epitope(s) was barely detectable on the surface of intact bacteria, despite Western blot analyses that revealed specific reactions between the MAbs and the LOS B band. The two LOS B-specific MAbs had no bacteriolytic activity against a LOS AB wild-type strain, while the control MAb BL-2, which is specific for the B. pertussis LOS A band, significantly reduced the number of living bacteria in the same assay. Moderate lytic activity against a mutant strain expressing only the LOS B band was observed for MAb BL-8 but not for MAb BL-9 or BL-2. These data demonstrate that the type, amount, and surface exposure of the LOS are related to the phenotype expressed by a specific B. pertussis strain. In addition, the LOS B MAbs also reveal the antigenic conservation of carbohydrate epitopes among B. pertussis and B. bronchiseptica strains.
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PMID:Immunological characterization of the lipooligosaccharide B band of Bordetella pertussis. 137 81


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