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

Escherichia coli K100 produces an antigenic determinant similar to, or identical with, the capsular antigen of Haemophilus influenzae type b. Studies of the effects of heat on the immunogenicity, erythrocyte-modifying capacity, and antigenicity of this cross-reacting antigen (CRA) revealed the following findings. Immunization of rabbits with viable or formaldehyde-killed suspensions of E. coli K100, producing CRA, engendered CRA antibodies in significant titers, as demonstrated by hemagglutination of erythrocytes modified by H. influenzae type b antigen. Heating of the suspensions for 1 h at 56 or 100 degrees C destroyed the immunogenicity of CRA, and the heated suspensions did not prime for a secondary antibody response. Supernatants of heated suspensions also were non-immunogenic. Repeated freezing and thawing of heated suspensions of E. coli K100 or their supernatants did not restore immunogenicity. Heat also abolished the immunogenicity of H. influenzae type b. The loss of immunogenicity of CRA of E. coli K100 by heat was not due to alteration of the antigenic determinant, since heated suspensions and supernatants thereof modified erythrocytes for agglutination by H. influenzae type b antiserum. The latter supernatants also inhibited hemagglutination by H. influenzae type b antibodies and absorbed the latter. We conclude that striking differences exist in the effects of heat on CRA on the one hand and of enterobacterial common antigen and lipopolysaccharide O antigen of enteric bacteria on the other. Heating of the latter two antigens does not abolish their priming effect, and repeated freezing and thawing restores the immunogenicity of heated antigens.
 ...
PMID:Effect of heat on antigenicity and immunogenicity of the antigenic determinant shared by Haemophilus influenzae type b and Escherichia coli K100. 7 Dec 69

Polyribophosphate (PRP), the capsular polysaccharide of Haemophilus influenzae type b, is more effectively immunogenic when it is associated with the bacterium than when it is in the purified form that is being tested as a vaccine for humans. In an effort to analyze this difference, we isolated from H. influenzae type b a high-molecular-weight, soluble complex, in which PRP appears to be combined with protein (about 7% protein). The pyrogenicity and limulus lysate gelation activity of the complex suggest that a small amount of lipopolysaccharide also is present. The protein was resolved into five polypeptides by electrophoresis in polyacrylamide gel containing sodium dodecyl sulfate. In weanling rabbits, which do not respond to purified PRP, the complex induces high titers of antibody of PRP, in an anamnestic pattern. Bactericidal antibody to other bacterial components was also elicited. Equilibrium density gradient centrifugation of the complex indicated that most of the immunogenicity of PRP resides in the least dense fractions, which are high in protein, low in polysaccharide, and active in the limulus lysate test; denser fractions that react strongly with limulus lysate but are poor in protein were much less immunogenic.
 ...
PMID:Immunogenicity in weanling rabbits of a polyribophosphate complex from Haemophilus influenzae type b. 30 92

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.
 ...
PMID:Characterization of lipopolysaccharide of Haemophilus influenzae. 31 Aug 55

Ribonucleic acid was removed from a phenol-water extract of Haemophilus influenzae type a by streptomycin sulfate. This preparation was called purified preparation or PP. It contained neutral sugars (glucose, galactose, mannose, pentose), glucosamine, amino acids, and fatty acids. Heptose and 2-keto-3-deoxyoctonic acid were not present. The biological properties and immunogenicity were compared with the activities of lipopolysaccharide of Escherichia coli or Salmonella typhimurium. Higher doses were necessary to obtain lethality in mice and Sanarelli and Shwartzman reactions with our preparations than were necessary with lipopolysaccharide. The Limulus test and pyrogen assay in rabbits gave the same results with purified preparation and lipopolysaccharide, but pyrogenicity of purified preparation was not destroyed by NaOH treatment. Purified preparation was not as immunogenic at low doeses for rabbits as lipopolysaccharide. The results were different from those obtained with lipopolysaccharide but similar to those known from peptidoglycan studies. The contamination of purified preparation with peptidoglycan was negligible and cannot explain the biological activities of purified preparation. We suggest that the phenol-water extract from H. influenzae is not a classical endotoxin, but rather an endotoxin-like substance.
 ...
PMID:Chemical composition and biological activities of a phenol-water extract from Haemophilus influenzae type a. 31 93

With the use of gas-liquid chromatographic techniques, the chemical characteristics of Streptococcus pneumoniae type 3, Escherichia coli, group B Neisseria meningitidis, Haemophilus influenzae type b, and Staphylococcus aureus, organisms that commonly cause bacterial meningitis, were identified. The combination of lipid, carbohydrate, and lipopolysaccharide components provided discriminating markers for chemotyping these bacteria. E. coli had a high content of 17- and 19-carbon cyclopropane fatty acids, whereas none of the other organisms tested revealed any cyclic acids, apart from a possible trace amount in S. pneumoniae. The content of isomethyl branching fatty acids clearly distinguished S. pneumoniae and S. aureus. N. meningitidis and H. influenzae were somewhat similar in their overall fatty acid compositions, but the presence of galactose without rhamnose in extracts of N. meningitidis readily distinguished N. meningitidis from H. influenzae. Only extracts from E. coli contained mannose; erythrose was an exclusive marker in extracts of S. pneumoniae. These data suggest that these differences in chemotype might be useful in developing a gas-liquid chromatographic assay of spinal fluid for the rapid laboratory diagnosis of bacterial meningitis.
 ...
PMID:Diagnosis of bacterial meningitis by gas-liquid chromatography. I. Chemotyping studies of Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, and Escherichia coli. 39 61

The gal locus from Haemophilus influenzae was cloned and sequenced. Four genes were identified by amino acid homology: galT, galK, galM and galR. The coding direction of galT, galK and galM is divergent from that of galR. There are non-coding intergenic regions between galR and galT, galT nd galK, and galK and galM. Deletion-insertion mutations constructed in galK and galE, which is in lic3, were moved into the H. influenzae chromosome generating each of the single mutants as well as the double gal mutant. Even when grown on complex media, the double mutant failed to react with an anti-lipopolysaccharide monoclonal antibody known to react with a digalactoside epitope. Both the galE single and the galE galK double mutants were serum-sensitive and relatively avirulent in infant rats, indicating a critical role for galactose metabolism, and providing evidence to support a central role for lipopolysaccharide, in H. influenzae virulence.
 ...
PMID:The gal locus from Haemophilus influenzae: cloning, sequencing and the use of gal mutants to study lipopolysaccharide. 128 42

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.
 ...
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

Protein carriers vary in their ability to increase the immunogenicity of poorly immunogenic or T-lymphocyte-independent antigens. We examined one such carrier, the outer membrane protein complex derived from Neisseria meningitidis serogroup B strain B11, in an attempt to determine why this outer membrane protein complex was more immunogenic in young infants and in relevant animal models than two other carriers used in conjugates made with Haemophilus influenzae type b polysaccharide, a T-cell-independent antigen. A single protein of the outer membrane protein complex, the class 2 porin protein, was purified and shown to function as a T-helper lymphocyte carrier protein. Unexpectedly, it was also found to have mitogenic activity for lymphocytes that was not due to lipopolysaccharide. This mitogenic activity appears to date to be unique to this carrier protein of the carrier proteins tested and may contribute to the ability of the H. influenzae type b conjugate vaccine made with the outer membrane protein complex to generate IgG anti-polysaccharide antibody responses in mice and infant monkeys and protective immune responses in infants less than 6 months of age.
 ...
PMID:A vaccine carrier derived from Neisseria meningitidis with mitogenic activity for lymphocytes. 153 34

The molecular basis of central nervous system invasiveness by Haemophilus influenzae has been studied by using genetically defined mutants and in vivo and in vitro model systems. Capsular polysaccharide and lipopolysaccharide are important microbial determinants of the ability of H. influenzae to traverse the nasopharynx and localize in the cerebrospinal fluid and meninges after bacteremia. The genes for type b capsule confer greater invasive potential than do those for other capsular polysaccharides, although the molecular basis for this is not understood. Mutants have also indicated the role of lipopolysaccharide in enhancing the efficiency of bacterial translocation from the nose to the blood and in facilitating intravascular survival. Organisms that localize successfully in the blood and central nervous system are the progeny of a small fraction of the original challenge inoculum, often a single bacterium.
 ...
PMID:Molecular basis of invasive Haemophilus influenzae type b disease. 158 86

In animal models, the lipopolysaccharide (LPS) from Haemophilus influenzae contributes to all the signs of meningitis associated with living bacteria. However, when tested in vitro, the amount of LPS in cerebrospinal fluid (CSF) in natural disease shows much greater effects on leukocytes than on endothelial permeability. To investigate whether other bacterial components act with LPS to incite meningeal inflammation, animals were challenged intracisternally with H. influenzae lysates. Upon neutralization of endotoxin, leukocytosis was greatly attenuated, but protein accumulation in CSF persisted. Cell wall from H. influenzae induced meningeal inflammation in a pattern opposite to that of LPS. Its ability to induce blood-brain barrier permeability greatly exceeded its ability to induce leukocytosis in vivo. Thus, cell wall, by acting on endothelia, and LPS, by inducing leukocytosis, may cooperate to induce inflammation in H. influenzae meningitis. Optimal reduction of inflammation and tissue damage in meningitis may require agents directed against cell wall as well as LPS.
 ...
PMID:Bacterial components and the pathophysiology of injury to the blood-brain barrier: does cell wall add to the effects of endotoxin in gram-negative meningitis? 158 87


1 2 3 4 5 6 7 8 9 10 Next >>