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

We characterized lipopolysaccharides (LPSs) from respiratory pathogenic Branhamella catarrhalis (BC) strains, and evaluated the protective property of anti-BC LPS antibody in BC respiratory infections. LPSs from four strains of BC were lipooligosaccharide having no O-side chain and a M(r) of 3 KDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). All of them produced different patterns, showing two to four bands on SDS-PAGE. We found high level of anti-BC IgG antibody in convalescent sera from a patient with BC respiratory tract infection by ELISA. This IgG antibody recognized BC LPSs on Western blots. Two respiratory pathogens of BC (strains; 87-122, 88-23) were tested in a bactericidal assay employing a convalescent sera. 87-122 strain was susceptible to antibody-dependent, complement-mediated killing, while 88-23 strain was resistant. The killing of 87-122 strain was inhibited by addition of the homologous BC LPS to the convalescent sera in a dose-dependent manner. These data support that anti-BC LPS antibody may mediate complement-lysis of some strains of BC, and play a protective role in BC respiratory infections.
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PMID:[Biochemical analysis of lipopolysaccharides from respiratory pathogenic Branhamella catarrhalis strains and the role of anti-LPS antibodies in Branhamella respiratory infections]. 143 52

Borrelia burgdorferi resembles gram-negative bacteria in having both cellular and outer membranes. We previously showed that a lipopolysaccharide (LPS)-like material could be extracted from B. burgdorferi with phenol-chloroform-petroleum ether (PCP). The PCP extract of B. burgdorferi exhibited biological activity in several in vitro assays (e.g., mitogenicity, pyrogenicity, and cytokine release). These activities suggested the presence of endotoxin. The PCP extract of B. burgdorferi, however, also contained a small amount of protein. Preliminary studies showed that monoclonal antibody prepared against this protein inhibited the mitogenic activity of the PCP extract toward murine spleen cells. The current study was therefore undertaken to characterize this protein and to establish methods for its separation from the LPS. The PCP-extracted protein consisted of a single, low-molecular-weight lipoprotein (apparent M(r), 10,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) (SDS-PAGE). By protein analysis, it accounted for 2% of the dry weight of defatted cells, thus making it a major constituent of the spirochete. It was purified from the LPS by initial extraction into 10% Triton X-100 followed by immunoaffinity chromatography in the presence of detergent. On removal of the LPS, the purified lipoprotein formed aggregates stable to SDS-PAGE which were detectable on Western blots (immunoblots) probed with either the monoclonal antibody or polyclonal antiserum. From a plot of the aggregate molecular weight versus aggregate size, a monomer molecular weight of 7,500 was obtained. Indirect immunofluorescence with the monoclonal antibody showed that the lipoprotein was exposed at the surface of the spirochete in only a small percentage of cells. The lipoprotein was present in several strains of B. burgdorferi but absent in other Borrelia spp., treponemes, and gram-negative human pathogens, indicating species specificity.
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PMID:Purification and immunological characterization of a major low-molecular-weight lipoprotein from Borrelia burgdorferi. 145 30

The ultrastructural features and molecular components of 18 strains of Fusobacterium necrophorum biovars A, AB and B, isolated from animal and human infections, were examined by electron microscopy, multilocus enzyme electrophoresis (MEE) and by sodium dodecyl sulfate-gradient polyacrylamide gel electrophoresis (SDS-PAGE). High resolution scanning electron microscopy revealed that the strains possessed a convoluted surface pattern. Transmission electron microscopy showed that all strains possessed a cell wall structure typical of gram-negative bacteria. Bleb formation was not uncommon. Numerous extracellular materials, resembling lipopolysaccharide (LPS) fragments, surrounded cells of both human strains and biovar B animal strains. Biovar A field strains revealed capsules as stained by ruthenium red whereas a stock culture strain showed the capsule only when immunostabilized with hyperimmune serum. Starch gel electrophoresis showed all strains to possess adenyl kinase, glutamate dehydrogenases and lactate dehydrogenase; each enzyme migrated uniformly (monomorphic) among the strains and represented an electrotype. However, SDS-PAGE indicated differences in the protein profiles between all of the strains; the most distinctly different was a human isolate (FN 606). Silver staining to detect LPS showed extensive "ladder" patterns among the majority of biovar A strains but not in the animal biovar B strains. Immunoblotting of LPS with a rabbit antiserum prepared against phenol extracted LPS from a biovar A animal isolate (LA 19) suggested marked variability in the LPS antigens among the isolates studied.
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PMID:Ultrastructure and molecular characterization of Fusobacterium necrophorum biovars. 147 1

A study recently conducted across Canada showed that 64 of 2,503 clinical isolates of Haemophilus influenzae were resistant to beta-lactams without production of a beta-lactamase (L. D. Tremblay, J. L'Ecuyer, P. Provencher, M. G. Bergeron, and Canadian Study Group, Can. Med. Assoc. J. 143:895-900, 1990). The beta-lactamase-negative strains formed three distinct groups, with ampicillin MICs of 0.5 to 1, 2 to 4, and greater than or equal to 8 micrograms/ml for groups I, II, and III, respectively. We have investigated the mechanisms of resistance for eight strains originating from different infections and geographic areas. These strains were representative of groups I to III. Five strains were nontypeable, two were type B, and one was non-B. Chromosomal DNA extracted from each strain was used to transform the laboratory strain Rd. Transformants were selected on beta-lactam-containing plates and showed the same level of resistance to ampicillin as the donor strains. Differences in outer membrane proteins, porins, and lipopolysaccharide profiles on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) did not change with resistance. Functional analyses of purified porins in artificial lipid bilayer experiments did not explain resistance. Peptidoglycan synthesis was measured by incorporation of [14C]alanine into trichloroacetic acid-insoluble cell wall material in the presence of chloramphenicol. The growth rate and the rate of peptidoglycan synthesis observed for the transformants of the isogenic set did not correlate with resistance. Whole-cell labeling with 125I-penicillin revealed modifications in penicillin-binding proteins (PBPs) among the transformants. In particular, PBPs 3A and 3B (65 and 63 kDa, respectively) showed a decrease in affinity for beta-lactams in all transformants (groups I, II, and III) and correlated with an increased MIC except in the transformant of group III, which showed higher levels of resistance. Partial purification and proteolytic digestion of 125I-penicillin-labeled PBP 3B led to two types of CnBr peptide profiles on SDS-PAGE, the profiles of the transformed strains from groups I and II being different from those of the control group and group III. Finally, electron microscopy revealed a distinct cell filamentation for the group III transformants. These data clearly indicate that changes in PBPs are a common mechanism that results in a significant level of non-beta-lactamase-mediated beta-lactam resistance in H. influenzae despite serotype, origin of isolation, or geographic distribution.
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PMID:Molecular basis of the non-beta-lactamase-mediated resistance to beta-lactam antibiotics in strains of Haemophilus influenzae isolated in Canada. 151 Apr 47

Sera from ten patients with positive brucella serology were used to investigate antibody cross-reactions between the O-antigens of Escherichia coli O157 and Yersinia enterocolitica O9. SDS-PAGE profiles of lipopolysaccharide (LPS), purified from strains of E. coli O157 and Y. enterocolitica O9, were reacted with sera by immunoblotting. All ten sera contained antibodies which bound to the LPS of E. coli O157, and five of these sera also contained antibodies which bound to the LPS of Y. enterocolitica O9. Absorption studies using these five cross-reacting sera indicated the existence of at least three epitopes exposed on the O-antigens of E. coli O157 and Y. enterocolitica O9. One antigen binding site appeared to be exposed on the LPS of both organisms, while one epitope was exposed on the LPS of E. coli O157 only, and another on the LPS of Y. enterocolitica O9 only.
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PMID:The serological relationship between Escherichia coli O157 and Yersinia enterocolitica O9 using sera from patients with brucellosis. 154 43

Outer membrane fractions (OMs) of nine Campylobacter (C.) jejuni and two C. coli strains belonging to different serovars, from human and various animal origins, were extracted by treatment with sodium N-lauryl sarcosinate. Using n-octyl-beta-D-glucopyranoside a 42-kDa protein and a flagella-enriched fraction were obtained. The capacity of the crude bacterial OM preparations, the purified 42-kDa protein and the flagella to bind to membranes of the human embryonic intestinal cell line INT 407 was tested by an enzyme-linked immunosorbent assay. The crude OM and the 42-kDa-enriched fraction were found to bind very well to the cell membranes, whereas the flagella preparation showed only a weak binding. Using monoclonal antibodies (mAbs) with HS 2-lipopolysaccharide (LPS) specificity, binding of crude HS 2 strain OM preparations to cell membranes was detected in a significant range, whereas with flagellin-specific mAbs binding of OMs and flagella to cell membranes was only detected to a very low extent. Binding of OMs to cell membranes was inhibited by preincubation of OMs with serovar-specific mouse hyperimmune serum, whereas on preincubation with mAbs directed against LPS or flagella binding was practically not inhibited. OMs extracted after pretreatment of the bacteria with proteinase K showed an altered SDS-PAGE pattern especially for the 42-kDa protein subunit and and their capacity to bind to cell membranes was significantly reduced. The binding was also reduced by preincubation of the OMs with L-fucose or D-mannose.
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PMID:In vitro binding of Campylobacter jejuni/coli outer membrane preparations to INT 407 cell membranes. 154 70

Sputum samples from seven patients with cystic fibrosis and chronic P. aeruginosa lung infection were investigated for immune complexes by PEG precipitation and in two different complement binding assays. All seven patients were immune complex positive. The components involved in immune complex formation were identified by SDS-PAGE and immunoblotting. We found P. aeruginosa lipopolysaccharide as a major antigen. Both core and O-specific saccharide antigens could be demonstrated. IgG and IgA were the immunoglobulins involved, with IgG2 as the dominating IgG subclass. Lipopolysaccharide has a number of biological activities and its presence in sputum may have consequences for the pathogenesis of lung disease in cystic fibrosis.
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PMID:Lipopolysaccharide is present in immune complexes isolated from sputum in patients with cystic fibrosis and chronic Pseudomonas aeruginosa lung infection. 155 93

The ATCC type strain and six clinical isolates of Campylobacter rectus were tested for toxicity against HL-60 cells and human polymorphonuclear neutrophils (PMNs). After challenge with bacterial cell suspensions and media supernatants for up to 4 h, eukaryotic cell viability was assayed by trypan blue dye exclusion and lactate dehydrogenase release. Cells of the C. rectus type strain were not toxic. However, ethanol and (NH4)2SO4 extracts of culture media supernatants killed HL-60 cells in a time and dose dependent manner with 700 micrograms of supernatant protein killing 100% of HL-60 cells in 4 h. Concentrated media supernatants from clinical isolates also killed 100% of HL-60 cells in 30 to 60 min. The bacterial culture supernatants were toxic to PMNs with clinical isolates killing 70 to 90% of PMNs in 2 to 4 h. SDS-PAGE and immunoblot analysis of the toxic media supernatants revealed C. rectus specific proteins and lipopolysaccharide (LPS). The toxic activity was inhibited by protease, indicating that the toxin was protein. Non-toxic and toxic media supernatants were obtained by altering hemin and fumarate in the growth media. SDS-PAGE analysis of these revealed that all toxic supernatants contained a 104 kDa protein.
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PMID:Production of an extracellular toxin by the oral pathogen Campylobacter rectus. 156 Jul 55

Production of the fourth component of complement (C4) by the human monocytic cell line U937 and its regulation were investigated in comparison with the production of the third component of complement (C3) in a cell culture system. Although no detectable C4 was produced by U937 without stimulation, U937 was induced by recombinant interferon-gamma (IFN-gamma) to synthesize C4 in a dose- and time-dependent fashion. The production of C4 was reversibly inhibited by cycloheximide, indicating that it resulted from de novo synthesis. The C4 synthesized by U937 cells was functionally active as assessed by haemolytic assay. SDS-PAGE following biosynthetic labelling showed that subunit structure of C4 synthesized by U937 cells was identical with that of plasma C4 but that molecular weight of alpha-chain was greater than that of plasma C4. We compared the regulation of C4 synthesis with that of C3 synthesis. Although C3 synthesis by U937 cells was enhanced by IFN-gamma, lipopolysaccharide (LPS) and phorbol myristate acetate (PMA), C4 synthesis was induced only by IFN-gamma. LPS and IFN-gamma induced a synergistic increase in C3 synthesis by U937 cells. U937 cells incubated with LPS and IFN-gamma synthesized a greater amount of C4 than those incubated with IFN-gamma alone. Thus it was demonstrated that the synthesis of C3 and C4 was independently regulated. This study shows that the U937 cell line provides a useful model for studies on the synthesis of complement proteins and on the regulation of complement production.
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PMID:Synthesis and regulation of the fourth component of complement (C4) in the human monocytic cell line U937: comparison with that of the third component of complement (C3). 159 31

Haemophilus influenzae type b (Hib) was grown in continuous culture under cystine-limitation between dilution rates (D) of 0.065-0.28 h-1. A similar outer-membrane protein profile, as adjudged by SDS-PAGE, was found at all dilution rates. However, a shift to a lipopolysaccharide structure with a greater electrophoretic mobility on SDS-PAGE with accompanying changes in monoclonal antibody reactivity was observed at D greater than or equal to 0.15 h-1. Growth rate per se can affect the expression of outer-membrane components of Hib.
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PMID:Growth of Haemophilus influenzae type b in continuous culture: effect of dilution rate on outer-membrane protein and lipopolysaccharide expression. 161 16


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