Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The capsular polymer (CP) of Haemophilus pleuropneumoniae serotype 5 was purified, and its chemical composition was analyzed. Radioimmunoassay experiments showed that the maximum amount of CP could be obtained from broth cultures of bacteria in the late stationary phase, rather than from bacteria washed off agar plates. The CP was precipitated from culture supernatant with 5 mM hexadecyltrimethylammonium bromide (Cetavlon) and solubilized with 0.4 M NaCl. Ninety percent of the CP in the culture supernatant was precipitated with Cetavlon, although some material remained insoluble after NaCl extraction. The CP was further purified by phenol extraction, ultracentrifugation, and Sepharose CL-4B gel filtration. The Kav of the CP from Sepharose CL-4B chromatography was 0.33. The CP preparation contained 85% hexosamine, 12% hexose, 3% phosphate, 0.17% protein, 0.20% nucleic acid, and 0.01% endotoxin. Thin-layer chromatography, an amino acid analyzer, and a glucose oxidase colorimetric kit were used to identify the sugar components of the hydrolyzed CP as glucosamine and glucose. Analysis of the native CP by 13C nuclear magnetic resonance indicated that amino, N-acetyl, and carboxyl groups were present and that the CP was a disaccharide.
 ...
PMID:Purification and partial characterization of the capsular polymer of Haemophilus pleuropneumoniae serotype 5. 359 1

Capsular structure and biochemical composition varied between two isolates (virulent and avirulent) of Haemophilus pleuropneumoniae serotype 5. The presence of capsule was determined by transmission electron microscopy with glutaraldehyde-osmium, ruthenium red, alcian blue, and phosphotungstic acid staining procedures. The virulent isolate of H. pleuropneumoniae had a distinct, adherent capsule. The avirulent isolate had a fragile, easily removed capsule. Capsular material (CM) and a lipopolysaccharide (LPS) were isolated from each bacterial isolate and were compared biochemically and biologically. CM from both isolates contained carbohydrates, no detectable protein, and no detectable to trace amounts of lipid A. Each LPS contained heptose, hexose, galactose, glucosamine, 2-keto-3-deoxyoctonate, and lipid A. Biological responses to CM and LPS from both isolates were demonstrated in the proclotting enzyme of Limulus polyphemus amebocyte lysate activation and in serological cross-reactions by immunofluorescence and immunodiffusion precipitation. The virulent isolate contained approximately 10 mg of LPS per g more on an original dry weight basis than the avirulent isolate. LPS from the virulent isolate contained approximately 13 times more galactose than LPS from the avirulent isolate. The differences of capsular structure and biochemical composition may contribute to the role of CM in porcine H. pleuropneumoniae infections.
 ...
PMID:Morphological and biochemical comparison of virulent and avirulent isolates of Haemophilus pleuropneumoniae serotype 5. 394 95

Haemophilus avium hemagglutinin properties were studied. Hemagglutination titer was decreased by proteolytic enzyme treatments, but was not affected by glycosidase, lipase, phospholipase, and neuraminidase treatments. Cell-free hemagglutinin was found in supernatants of centrifuged sonicate and centrifuged agitate of H avium and was precipitated with ammonium sulfate with no loss of hemagglutinating activity. The H avium hemagglutinin showed different patterns of activity against the RBC of different avian species. Hemagglutination of chicken RBC was not inhibited by D-mannose.
 ...
PMID:Characterization and chemical nature of Haemophilus avium hemagglutinin. 707 65

The ability of surfactant protein A (SP-A) to aggregate and opsonize type a and b Hemophilus influenzae was investigated. Type a, but not type b, was aggregated by SP-A. Aggregation was maximal at 24 micrograms SP-A/ml and was Ca(2+)-dependent. Aggregation of type a was inhibited by D-glucosyl-BSA but not by high concentrations of monosaccharides (D-mannose, D-galactose, D-glucose, or L-fucose) or by sialic acid, purified type a capsular polysaccharide, or type IV collagen. In Western blots, 125I-labeled SP-A bound to the major outer membrane protein (putatively P2) of type a hemophilus by a Ca(2+)-dependent mechanism. This binding was competitively inhibited by excess unlabeled SP-A. 125I-labeled SP-A also bound to the major membrane protein of type b, but at less than 5% of the level observed for type a. SP-A did not bind to lipooligosaccharides of either type a or type b. SP-A increased association of type a, but not type b, hemophilus with alveolar macrophages. After opsonization with SP-A, type a hemophilus were killed by alveolar macrophages, as indicated by bactericidal assays and the release of soluble, radiolabeled products from leukocytes. It is concluded that SP-A aggregated and opsonized type a hemophilus, but not type b, possibly because SP-A bound to the P2 outer membrane protein of type a to a greater extent.
 ...
PMID:Aggregation and opsonization of type A but not type B Hemophilus influenzae by surfactant protein A. 801 34

Lipopolysaccharide (LPS) is a major virulence determinant of Haemophilus influenzae. The organism is capable of expressing a heterogeneous population of LPS which exhibits extensive antigenic diversity among multiple oligosaccharide (OS) epitopes. Structural elucidation of variable and conserved OS epitopes of H. influenzae serotype b strain Eagan was determined by the application of high-field NMR techniques and MS-based methods on oligosaccharides obtained from LPS samples by a deacylation strategy. LPS extracted by the hot aqueous phenol method gave complex electrophoretic patterns consisting of at least six low-molecular mass bands. Electrospray ionization-mass spectrometry of O-deacylated LPS revealed a series of related structures differing in the number of hexose residues as well as subpopulations of glycoforms containing additional phosphoethanolamine (PEA) groups. It was demonstrated that the LPS contains a conserved PEA-substituted, heptose-containing trisaccharide inner core moiety attached via a KDO 4-phosphate unit to a lipid A component. Tandem MS experiments unambiguously established the presence of a KDO 4-pyrophosphoethanolamine unit in the subpopulation of LPS containing additional PEA groups. The occurrence of LPS containing this structural feature was found to be dependant on the isolation procedure used. Each heptose of the common inner core element L-alpha-D-Hepp(1-->2)-L-alpha-D-Hepp(1-->3)-L-alpha-D-Hep p(1-->5)-alpha-KDO is substituted by a hexose residue with further chain elongation from the central unit. The structures of the major glycoforms containing four (three Glcs and one Gal), five (three Glcs and two Gals), and six (three Glcs and three Gals) hexoses were determined in detail. The Hex6 glycoform contains the terminal structure, alpha-D-Galp(1-->4)-beta-D-Galp(1-->4)-beta-D-Glc, providing, for the first time, definitive structural evidence for the expression of the Pk-blood group antigen in H. influenzae LPS. Moreover, an analogue of the Hex4 glycoform was identified in which the third heptose residue carries phosphate at 0-4.
 ...
PMID:Structure of the variable and conserved lipopolysaccharide oligosaccharide epitopes expressed by Haemophilus influenzae serotype b strain Eagan. 904 8

Structural elucidation of the lipopolysaccharide (LPS) of Haemophilus influenzae, strain Rd, a capsule-deficient type d strain, has been achieved by using high-field NMR techniques and electrospray ionization-mass spectrometry (ESI-MS) on delipidated LPS and core oligosaccharide samples. It was found that this organism expresses heterogeneous populations of LPS of which the oligosaccharide (OS) epitopes are subject to phase variation. ESI-MS of O-deacylated LPS revealed a series of related structures differing in the number of hexose residues linked to a conserved inner-core element, L-alpha-D-Hepp-(1-->2)-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp- (1-->4)-]- L-alpha-D-Hepp-(1-->5)-alpha-Kdo, and the degree of phosphorylation. The structures of the major LPS glycoforms containing three (two Glc and one Gal), four (two Glc and two Gal) and five (two Glc, two Gal and one GalNAc) hexoses were substituted by both phosphocholine (PCho) and phosphoethanolamine (PEtn) and were determined in detail. In the major glycoform, Hex3, a lactose unit, beta-D-Galp-(1-->4)-beta-D-Glcp, is attached at the O-2 position of the terminal heptose of the inner-core element. The Hex4 glycoform contains the PK epitope, alpha-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-beta-D-Glcp while in the Hex5 glycoform, this OS is elongated by the addition of a terminal beta-D-GalpNAc residue, giving the P antigen, beta-D-GalpNAc-(1-->3)-alpha-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-D-Glc p. The fully extended LPS glycoform (Hex5) has the following structure. [see text] The structural data provide the first definitive evidence demonstrating the expression of a globotetraose OS epitope, the P antigen, in LPS of H. influenzae. It is noteworthy that the molecular environment in which PCho units are found differs from that observed in an Rd- derived mutant strain (RM.118-28) [Risberg, A., Schweda, E. K. H. & Jansson, P-E. (1997) Eur. J. Biochem. 243, 701-707].
 ...
PMID:Structural analysis of the lipopolysaccharide oligosaccharide epitopes expressed by a capsule-deficient strain of Haemophilus influenzae Rd. 1010 48

The structure of the lipopolysaccharide of Haemophilus influenzae mutant strain, RM.118-26, was investigated. Electrospray ionization-mass spectrometry on intact lipopolysaccharide, O-deacylated lipopolysaccharide and core oligosaccharides obtained from lipopolysaccharide after mild acid hydrolysis provided information on the composition and relative abundance of the glycoforms. Oligosaccharide samples were studied in detail using high-field NMR techniques. The structure of the major glycoform containing phosphocholine is identical to the Hex2 glycoform described for H. influenzae RM.118-28 [Risberg, A., Schweda, E.K.H. & Jansson, P.-E. (1997) Eur. J. Biochem. 243, 701-707]. A second major glycoform, containing three hexose residues (Hex3), in which a lactose unit, beta-D-Galp-(1-->4)-beta-D-Glcp, is attached at the O-2 position of the terminal heptose of the inner core element, L-alpha-D-Hepp-(1-->2)-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-( 1-->4)-]- L-alpha-D-Hepp-(1-->5)-alpha-Kdo, carries no phosphocholine. Instead this lipopolysaccharide glycoform is partly (40%) substituted by an O-acetyl group linked to the 6-position of the glucose residue in the lactose unit and has the following structure:
 ...
PMID:Structural analysis of the lipopolysaccharide oligosaccharide epitopes expressed by Haemophilus influenzae strain RM.118-26. 1051 3

The lic1 locus of Haemophilus influenzae controls the incorporation of environmental choline into lipopolysaccharide (LPS) as phosphorylcholine (ChoP) as well as the phase variation of this structure. ChoP is the target of an acute phase reactant in serum, C-reactive protein (CRP), which mediates killing through the activation of complement when bound to the organism. Structural analysis of the oligosaccharide region of the H. influenzae LPS showed that ChoP is linked to different hexose residues on different chain extensions in strains Rd and Eagan. Differences in the molecular environment of ChoP affect the epitope defined by monoclonal antibody 12D9 and were associated with polymorphisms within LicD, a putative diphosphonucleoside choline transferase. Exchanging the licD genes between the two strains with ChoP on different chain extensions was sufficient to switch its position. Allelic variants with ChoP on a hexose on heptose III rather than heptose I were sensitive to CRP-mediated serum bactericidal activity regardless of the genetic background. Differences in CRP-mediated killing correlated with differences in the binding of CRP from human serum to whole bacteria. This suggests that, in addition to the mechanism involving phase variation, the structural rearrangements within the oligosaccharide contribute to evasion of innate and acquired immunity.
 ...
PMID:The position of phosphorylcholine on the lipopolysaccharide of Haemophilus influenzae affects binding and sensitivity to C-reactive protein-mediated killing. 1063 93

Haemophilus influenzae expresses heterogeneous populations of short-chain lipopolysaccharide (LPS) which exhibit extensive antigenic diversity among multiple oligosaccharide epitopes. These LPS oligosaccharide epitopes can carry phosphocholine (PCho) substituents, the expression of which is subject to high frequency phase variation mediated by genes in the lic1 genetic locus. The location and site of attachment of PCho substituents were determined by structural analysis of LPS from two type b H. influenzae strains, Eagan and RM7004. The lic2 locus is involved in phase variation of oligosaccharide expression. LPS obtained from the parent strains, from mutants generated by insertion of antibiotic resistance cassettes in the lic2 genetic locus, and from phase-variants showing high levels of PCho expression was characterized by electrospray ionization-mass spectrometry (ESI-MS) and 1H NMR spectroscopy of derived O-deacylated samples. ESI-MS of O-deacylated LPS from wild-type strains revealed mixtures of related glycoform structures differing in the number of hexose residues. Analysis of LPS from PCho-expressing phase-variants revealed similar mixtures of glycoforms, each containing a single PCho substituent. O-Deacylated LPS preparations from the lic2 mutants were much less complex than their respective parent strains, consisting only of Hex3 and/or Hex2 glycoforms, were examined in detail by high-field NMR techniques. It was found that the LPS samples contain the phosphoethanolamine (PEtn) substituted inner-core element, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1--> 3)-L-alpha-D-He pp-(1-->5)-alpha-Kdo in which the major glycoforms carry a beta-D-Glcp or beta-D-Glcp-(1-->4)-beta-D-Glcp at the O-4 position of the 3-substituted heptose (HepI) and a beta-D-Galp at the O-2 position of the terminal heptose (HepIII). LPS from the lic2 mutants of both type b strains were found to carry PCho groups at the O-6 position of the terminal beta-D-Galp residue attached to HepIII. In the parent strains, the central heptose (HepII) of the LPS inner-core element is also substituted by hexose containing oligosaccharides. The expression of the galabiose epitope in LPS of H. influenzae type b strains has previously been linked to genes comprising the lic2 locus. The present study provides definitive evidence for the role of lic2 genes in initiating chain extension from HepII. From the analysis of core oligosaccharide samples, LPS from the lic2 mutant strain of RM7004 was also found to carry O-acetyl substituents. Mono-, di-, and tri-O-acetylated LPS oligosaccharides were identified. The major O-acetylated glycoforms were found to be substituted at the O-3 position of HepIII. A di-O-acetylated species was characterized which was also substituted at the O-6 postion of the terminal beta-D-Glc in the Hex3 glycoform. This is the first report pointing to the occurrence of O-acetyl groups in the inner-core region of H. influenzae LPS. We have previously shown that in H. influenzae strain Rd, a capsule-deficient type d strain, PCho groups are expressed in a different molecular environment, being attached at the O-6 position of a beta-D-Glcp, which is in turn attached to HepI.
 ...
PMID:Characterization of the phosphocholine-substituted oligosaccharide in lipopolysaccharides of type b Haemophilus influenzae. 1084 10

Lipooligosaccharide (LOS) glycoforms from Haemophilus influenzae 2019 were profiled using the high-resolution and accurate mass capabilities of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Sequence and linkage for two previously unknown LOS glycoforms were subsequently obtained through MSn analyses on FT-ICR and quadrupole ion trap (qIT) instruments. MSn analysis of negative ion precursors confirmed structural details within the lipid moiety, while CID spectra of sodiated precursor ions provided monosaccharide sequence and linkage for the oligosaccharide portion of the molecule. Results obtained in this study indicate that extensive heterogeneity exists within the oligosaccharide moieties in LOS from H. influenzae 2019. More importantly, the data suggest that additional hexose moieties, which are added onto the LOS, are not simple extensions of one particular core structure but rather that structural isomers with different connectivities are present within the heterogeneous mixture.
 ...
PMID:Mass spectral characterization of lipooligosaccharides from Haemophilus influenzae 2019. 1101 21


1 2 3 Next >>