Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The possibility to use immunomodulators isolated from marine invertebrates for the lowering of the toxic effects caused by Yersinia pseudotuberculosis thermoresistant toxin and lipopolysaccharide was investigated. Effects were evaluated by the animals survival rate in per cent and mice average lifetime after toxin lethal dose injection. It was shown that polypeptide gangleen when compared to timalin as well as glycanes mitilane and strombus had dose-dependent protective effect. These substances increased animals survival rate to 15-17 per cent and prolonged life period for about two times when compared to control group. These results demonstrates the possibility to use investigated immunomodulators is clinical practice at the treatment of the patients with pseudotuberculosis.
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PMID:[Use of immunomodulators isolated from marine invertebrates for reducing the toxic effects of thermostable toxin and lipopolysaccharides from Yersinia pseudotuberculosis on a macroorganism]. 1169 37

Yersinia pestis, the causative agent of plague, and the enteropathogen Yersinia pseudotuberculosis have nearly identical nucleotide similarity yet cause markedly different diseases. To investigate this conundrum and to study Yersinia pathogenicity, we developed a high-density oligonucleotide array-based modification of signature-tagged mutagenesis (STM). Y. pseudotuberculosis YPIII mutants constructed with the tagged transposons were evaluated in the murine yersiniosis infection model. The DNA tags were amplified using biotinylated primers and hybridized to high-density oligonucleotide arrays containing DNA complementary to the tags. Comparison of the hybridization signals from input pools and output pools identified a mutant whose relative abundance was significantly reduced in the output pool. Sequence data from 31 transposon insertion regions was compared to the complete Y. pestis CO92 genome sequence. The 26 genes present in both species were found to be almost identical, but five Y. pseudotuberculosis genes identified through STM did not have counterparts in the Y. pestis genome and may contribute to the different tropisms in these closely related pathogens. Potential virulence genes identified include those involved in lipopolysaccharide biosynthesis, adhesion, phospholipase activity, iron assimilation, and gene regulation. The phospholipase A (PldA) mutant exhibited reduced phospholipase activity compared to the wild-type strain and in vivo attenuation of the mutant was confirmed. The combination of optimized double tag sequences and high-density array hybridization technology offers improved performance, efficiency, and reliability over classical STM and permits quantitative analysis of data.
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PMID:Application of high-density array-based signature-tagged mutagenesis to discover novel Yersinia virulence-associated genes. 1170 63

The enzyme CDP-D-glucose 4,6-dehydratase (EC 4.2.1.45) is an NAD(+)-dependent oxidoreductase which catalyzes the irreversible conversion of CDP-D-glucose to CDP-4-keto-6-deoxy-D-glucose. The product of this reaction is an intermediate in the synthesis of all CDP-linked 3,6-dideoxyhexoses, an important class of antigenic determinants found in the lipopolysaccharide layer of Gram-negative bacteria. Crystals of a recombinant form of this enzyme from Yersinia pseudotuberculosis have been grown in two crystal forms, both possessing pseudo-translational non-crystallographic symmetry, with dramatically different diffraction characteristics. A complete 1.8 A data set has been collected from the primitive orthorhombic crystal form, for which the non-crystallographic symmetry is described in detail.
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PMID:Purification, crystallization and molecular symmetry of CDP-D-glucose 4,6-dehydratase from Yersinia pseudotuberculosis. 1180 80

O antigen is part of the lipopolysaccharide present in the outer membrane of gram-negative bacteria and is highly polymorphic. In this study, we obtained sequences of the O-antigen gene clusters for the Yersinia pseudotuberculosis antigens IA, IIA, and IVB. We propose that the IIA gene cluster was derived from the IVB cluster, one of the very few cases in which a parent gene cluster is identified, and that the IA gene cluster could be a hybrid of the IVB and IB gene clusters. All three O antigens contain 6-deoxy-D-mannoheptose, and we identified six genes for the biosynthetic pathway for the precursor of this sugar, GDP-6-deoxy-D-mannoheptose.
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PMID:Relationship of Yersinia pseudotuberculosis O antigens IA, IIA, and IVB: the IIA gene cluster was derived from that of IVB. 1201 Oct 23

In the present paper, we demonstrated that low concentrations of various polycationic agents sensitize E. coli HB 101 harboring the plasmid pRI203, containing the Y. pseudotuberculosis invasion region, to antibiotics rifampicin, amikacin, ceftazidime and cefotaxime. These antibiotics, known to be excluded, to various degrees, by the bacterial outer membrane, resulted several-fold more active towards polycation-treated bacteria by comparison with controls. This increased permeability to antibiotics of E. coli HB 101 (pRI203) probably depends upon the binding of polycations to the acidic moieties of lipopolysaccharide, as already suggested for other gram-negative bacteria.
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PMID:Effect of antibiotics on polycation-treated Escherichia coli HB101 (pRI203). 1204 65

The impact of two plasmid (47, 82 MD), single plasmid (47 MD) and non plasmid Y. pseudotuberculosis strains, Y. enterocolitica (47 MD) as well as Y. pseudotuberculosis superantigen (YPM) on the production of interleukin-1 (IL-1), interleukin-6 (IL-6), interferon-alpha (IFN = alpha) and tumor necrosis factor alpha (TNF-alpha) by whole blood cells obtained from donors was studied. All Y. pseudotuberculosis and Y. enterocolitica strains stimulated the production of IFN-alpha, IL-1, IL-6 and TNF-alpha by whole blood cells, but considerably less than Y. pseudotuberculosis lipopolysaccharide and YPM. These data are indicative of the pathogenetic role played by 82 MD plasmid in manifestation of Y. pseudotuberculosis immunosuppressive properties. The maximum stimulation of the production of cytokines was observed under the action of YPM, which confirmed an important role played by this superantigen in the pathogenesis of Y. pseudotuberculosis.
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PMID:[Impact of Yersinia pseudotuberculosis on the in vitro production of cytokines by whole blood cells of donors]. 1244 99

Pathogenic biotypes of Yersinia enterocolitica (serotypes O:3, O:8, O:9, and O:13), but not environmental biotypes (serotypes O:5, O:6, O:7,8, and O:7,8,13,19), increased their permeability to hydrophobic probes when they were grown at pH 5.5 or in EGTA-supplemented (Ca(2+)-restricted) media at 37 degrees C. A similar observation was also made when representative strains of serotypes O:8 and O:5 were tested after brief contact with human monocytes. The increase in permeability was independent of the virulence plasmid. The role of lipopolysaccharide (LPS) in this phenomenon was examined by using Y. enterocolitica serotype O:8. LPS aggregates of bacteria grown in acidic or EGTA-supplemented broth took up more N-phenylnaphthylamine than LPS aggregates of bacteria grown in standard broth and also showed a marked increase in acyl chain fluidity which correlated with permeability, as determined by measurements obtained in the presence of hydrophobic dyes. No significant changes in O-antigen polymerization were observed, but lipid A acylation changed depending on the growth conditions. In standard medium at 37 degrees C, there were hexa-, penta-, and tetraacyl lipid A forms, and the pentaacyl form was dominant. The amount of tetraacyl lipid A increased in EGTA-supplemented and acidic media, and hexaacyl lipid A almost disappeared under the latter conditions. Our results suggest that pathogenic Y. enterocolitica strains modulate lipid A acylation coordinately with expression of virulence proteins, thus reducing LPS packing and increasing outer membrane permeability. The changes in permeability, LPS acyl chain fluidity, and lipid A acylation in pathogenic Y. enterocolitica strains approximate the characteristics in Yersinia pseudotuberculosis and Yersinia pestis and suggest that there is a common outer membrane pattern associated with pathogenicity.
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PMID:Pathogenic Yersinia enterocolitica strains increase the outer membrane permeability in response to environmental stimuli by modulating lipopolysaccharide fluidity and lipid A structure. 1265 21

To investigate Yersinia pathogenicity and the evolutionary divergence of the genus, the effect of pathogenic yersiniae on the model organism Caenorhabditis elegans was studied. Three strains of Yersinia pestis, including a strain lacking pMT1, caused blockage and death of C. elegans; one strain, lacking the haemin storage (hms) locus, caused no effect. Similarly, 15 strains of Yersinia enterocolitica caused no effect. Strains of Yersinia pseudotuberculosis showed different levels of pathogenicity. The majority of strains (76 %) caused no discernible effect; 5 % caused a weak infection, 9.5 % an intermediate infection, and 9.5 % a severe infection. There was no consistent relationship between serotype and severity of infection; nor was there any relationship between strains causing infection of C. elegans and those able to form a biofilm on an abiotic surface. Electron microscope and cytochemical examination of infected worms indicated that the infection phenotype is a result of biofilm formation on the head of the worm. Seven transposon mutants of Y. pseudotuberculosis strain YPIII pIB1 were completely or partially attenuated; mutated genes included genes encoding proteins involved in haemin storage and lipopolysaccharide biosynthesis. A screen of 15 defined C. elegans mutants identified four where mutation caused (complete) resistance to infection by Y. pseudotuberculosis YPIII pIB1. These mutants, srf-2, srf-3, srf-5 and the dauer pathway gene daf-1, also exhibit altered binding of lectins to the nematode surface. This suggests that biofilm formation on a biotic surface is an interactive process involving both bacterial and invertebrate control mechanisms.
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PMID:A Caenorhabditis elegans model of Yersinia infection: biofilm formation on a biotic surface. 1460 Feb 34

The interaction of Yersinia pseudotuberculosis porin solubilized in deoxycholate with the S- and R-forms of endogenous lipopolysaccharide (LPS) was studied by the quenching of intrinsic protein fluorescence. The samples of S-LPS differed both in the length of O-specific polysaccharide (n = 1 and 4) and in the acylation degree of the 3-hydroxytetradecanoic acid residues of the lipid A moiety (12-66%). R-LPS (12%) binding to porin was found to occur with positive cooperativity on two integrated structural regions of the R-LPS macromolecule, namely, core oligosaccharide and lipid A. The mode of porin interaction with low-acylated S-LPSs (15 or 20%) coincided with a model involving three types of binding sites. The shape of Scatchard curves of binding indicates that a complex formation between porin and low-acylated S-LPS is cooperative at low and moderate ligand concentration, whereas at near-saturating LPS concentrations porin binds to LPS independently on two types of binding sites. The O-specific polysaccharide chain in the S-LPS macromolecule increases the affinity of its interaction with porin in comparison with R-LPS-porin binding. A significant increase (to 66%) in the degree of S-LPS acylation substantially changed its porin-binding character: the process became anti-cooperative with lowered affinity. Thus, the features of LPS-porin interaction significantly depend on the conformational changes in the LPS molecule due to expanding of its hydrophobic region.
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PMID:Interaction of porin from Yersinia pseudotuberculosis with different structural forms of endogenous lipopolysaccharide. 1460 39

The O-antigen of lipopolysaccharide (LPS) is a virulence factor in enterobacterial infections, and the advantage of its genetic loss in the lethal pathogen Yersinia pestis has remained unresolved. Y. pestis and Salmonella enterica express beta-barrel surface proteases of the omptin family that activate human plasminogen. Plasminogen activation is central in pathogenesis of plague but has not, however, been found to be important in diarrhoeal disease. We observed that the presence of O-antigen repeats on wild-type or recombinant S. enterica, Yersinia pseudotuberculosis or Escherichia coli prevents plasminogen activation by PgtE of S. enterica and Pla of Y. pestis; the O-antigen did not affect incorporation of the omptins into the bacterial outer membrane. Purified His6-Pla was successfully reconstituted with rough LPS but remained inactive after reconstitution with smooth LPS. Expression of smooth LPS prevented Pla-mediated adhesion of recombinant E. coli to basement membrane as well as invasion into human endothelial cells. Similarly, the presence of an O-antigen prevented PgtE-mediated bacterial adhesion to basement membrane. Substitution of Arg-138 and Arg-171 of the motif for protein binding to lipid A 4'-phosphate abolished proteolytic activity but not membrane translocation of PgtE, indicating dependence of omptin activity on a specific interaction with lipid A. The results suggest that Pla and PgtE require LPS for activity and that the O-antigen sterically prevents recognition of large-molecular-weight substrates. Loss of O-antigen facilitates Pla functions and invasiveness of Y. pestis; on the other hand, smooth LPS renders plasminogen activator cryptic in S. enterica.
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PMID:Lack of O-antigen is essential for plasminogen activation by Yersinia pestis and Salmonella enterica. 1465 23


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