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

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.
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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.
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PMID:Mass spectral characterization of lipooligosaccharides from Haemophilus influenzae 2019. 1101 21

The lipooligosaccharide (LOS) of Haemophilus somnus undergoes antigenic phase variation, which may facilitate evasion from the bovine host immune response and/or colonization and dissemination. However, LOS antigenic diversity in H. somnus has not been adequately investigated. In this study, monoclonal antibodies (MAbs) specific to various LOS epitopes were used to investigate antigenic variation and stability in LOS from H. somnus strains and phase variants. Clinical isolates of H. somnus exhibited intrastrain, as well as interstrain, antigenic heterogeneity in LOS when probed with MAbs to outer core oligosaccharide epitopes in an enzyme-linked immunosorbent assay (ELISA). However, epitopes reactive with MAbs directed predominately to the inner core heptose region were highly conserved. At least one epitope, which was expressed in few strains, was identified. One LOS component affected by phase variation was identified as phosphorylcholine (PCho), which is linked to the primary glucose residue. Inhibition ELISA, immunoblotting, and electrospray-mass spectrometry were used to confirm that MAb 5F5.9 recognized PCho. LOS reactivity with MAb 5F5.9 was associated with loss of most of the outer core oligosaccharide, indicating that reactivity with PCho was affected by phase variation of the glucose residues in this region. Our results indicate that outer core epitopes of H. somnus LOS exhibit a high degree of random, phase-variable antigenic heterogeneity and that such heterogeneity must be considered in the design of vaccines and diagnostic tests.
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PMID:Antigenic diversity of Haemophilus somnus lipooligosaccharide: phase-variable accessibility of the phosphorylcholine epitope. 1110 73

Glycerol kinase (EC 2.7.1.30) is a bacterial sugar kinase and a member of the sugar kinase/actin/hsc-70 superfamily of enzymes. The enzyme from Escherichia coli is an allosteric regulatory enzyme whose activity is inhibited by fructose 1,6-bisphosphate (FBP) and the glucose-specific phosphocarrier of the phosphoenolpyruvate:glycose phosphotransferase system, IIA(Glc) (previously termed III(Glc)). Comparison of its primary structure with that of the highly similar Haemophilus influenzae glycerol kinase reveals that the amino acid sequence for the binding site for FBP is conserved while the amino acid sequence for the binding site for IIA(Glc) contains differences that are predicted to prevent its inhibition. To test this hypothesis, the H. influenzae glpK gene was assembled from DNA library fragments and subcloned into pUC18. The enzyme is expressed at high levels in E. coli. It was purified to greater than 90% homogeneity by taking advantage of its solubility behavior in a procedure that requires no column chromatography. The initial-velocity kinetic parameters of the purified enzyme are similar to those of the E. coli glycerol kinase. The H. influenzae glycerol kinase is inhibited by FBP but not by IIA(Glc), in agreement with the prediction based on sequence comparison. Sedimentation velocity experiments reveal that inhibition of HiGK by FBP is associated with oligomerization, behavior which is similar to EcGK. The possibility of utilizing mutagenesis studies to exploit the high degree of similarity of these two enzymes to elucidate the mechanism of allosteric regulation by IIA(Glc) is discussed.
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PMID:Subcloning, expression, purification, and characterization of Haemophilus influenzae glycerol kinase. 1138 99

The aim of this study was to compare the efficacy of conservation by freezing the strains of Haemophilus influenzae at -20 degrees C and -70 degrees C. Skim milk supplemented with glucose, yeast extract and glycerol allowed highest viability of H. influenzae both at -20 degrees C and -70 degrees C from the media analyzed. Trypticase soy broth and brain heart infusion broth supplemented with glycerol, allowed excellent recovery. Use of cotton swaps as supporting material, with or without addition of cryoprotective agents, did not modify H. influenzae viability after six months of storage. Concentration of the initial inoculum positively affected viability when stored at -20 degrees C. Initial concentration did not influence survival after storage at -70 degrees C. Thawing at room temperature should not exceed 3 h as to get highest survival percentage.
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PMID:A comparative study of preservation and storage of Haemophilus influenzae. 1139 34

The fur gene of Pasteurella multocida has been cloned by complementation of an Escherichia coli fur mutant. The P. multocida fur gene, which encodes a predicted protein of 147 amino acids, displaying the highest identity (89%) with the same protein of Haemophilus influenzae, is negatively regulated by its own product. By construction of a P. multocida fur mutant, it has been demonstrated that the ompH gene, encoding a major structural protein of the outer membrane, presenting high antigenicity power, is negatively regulated by iron and glucose. Furthermore, wild-type and fur-defective cells of P. multocida show the same level of virulence.
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PMID:Expression of the Pasteurella multocida ompH gene is negatively regulated by the Fur protein. 1155 37

The structure of the core region of the lipopolysaccharide (LPS) from the nontypable Haemophilus influenzae strain SB 33 was elucidated. The LPS was subjected to a variety of degradative procedures. The structures of the derived oligosaccharide products were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. These analyses revealed a series of related phosphocholine (PCho) containing structures differing in the number of hexose residues. The results pointed to each species containing a conserved phosphoethanolamine (PEtn) substituted heptose-containing trisaccharide inner-core moiety. The major LPS glycoforms were identified as 2-Hex, 3-Hex and 4-Hex species according to the number of hexose residues present.
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PMID:Structural analysis of the lipopolysaccharide from the nontypable Haemophilus influenzae strain SB 33. 1160 89

The in-vitro antibacterial activity of cefpiramide was compared with those of 15 other broad-spectrum cephalosporins. A total of 440 clinical strains of bacteria, including 9 bacterial species, were isolated from our hospital in 1998. The minimum inhibitory concentrations (MICs) of cefpiramide and five other antibiotics were determined for each species, using the agar-dilution method. The MIC of cefpiramide for Escherichia coli and Klebsiella pneumoniae was higher than those of three other third-generation cephalosporins, (ie, cefoperazone, ceftazidime, and ceftriaxone). Fifty-one percent (26/51) of Enterobacter cloacae isolates were resistant to cefpiramide. Cefoperazone/sulbactam and cefepime had greater activity against E. cloacae (resistance, 3.9% and 19.6%, respectively) than cefpiramide. Cefpiramide was more active against Pseudomonas aeruginosa (resistance rates, 12%) than cefoperazone, ceftazidime, ceftriaxone, aztreonam, and cefepime. Cefpiramide-resistant P. aeruginosa strains were resistant to ceftazidime, but 27% of ceftazidime-resistant strains were susceptible to cefpiramide; 15.3% of cefpiramide-resistant S. maltophilia strains were also susceptible to ceftazidime, but 50% of ceftazidime-resistant strains were still susceptible to cefpiramide. Cefoperazone/sulbactam was the most active agent against Acinetobacter baumannii, showing a resistance rate of 2%. Ampicillin/sulbactam, ceftazidime, and cefpiramide were the second most active agents, and about 50% of the tested strains were susceptible to these three antibiotics. Cefpiramide had an activity comparable to that of all tested beta-lactams against oxacillin-susceptible Staphylococcus aureus (MIC90, 2 microg/ml). Against Streptococcus pneumoniae and Haemophilus influenzae, cefpiramide had good activity, with an MIC90 concentration at which 90% of the strain was inhibited of 1 microg/ml and 0.5 microg/ml, respectively. These results indicated that cefpiramide was more active against glucose non-fermenting bacteria than against Enterobacteriaceae, and was very active against oxacillin-susceptible Staphylo-coccus aureus, S. pneumoniae, and H. influenzae. Thus, cefpiramide may be a good choice of drug for the treatment of patients with infections with glucose non-fermenting bacteria and community acquired infections.
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PMID:In-vitro antibacterial activities of cefpiramide and other broad-spectrum antibiotics against 440 clinical isolates in China. 1181 May 40

Structural analysis of the lipopolysaccharide (LPS) of nontypeable Haemophilus influenzae strain 1003 has been achieved by the application of high-field NMR techniques, ESI-MS, capillary electrophoresis coupled to ESI-MS, composition and linkage analyses on O-deacylated LPS and core oligosaccharide material. It was found that the LPS contains the common structural element of H. influenzae, l-alpha-D-Hepp-(1-->2)-[PEtn-->6]-l-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-l-alpha-D-Hepp-(1-->5)-[PP Etn-->4]-alpha-Kdop-(2-->6)-Lipid A, in which the beta-D-Glcp residue is substituted by phosphocholine at O-6 and an acetyl group at O-4. A second acetyl group is located at O-3 of the distal heptose residue (HepIII). HepIII is chain elongated at O-2 by either a beta-D-Glcp residue (major), lactose or sialyllactose (minor, i.e. alpha-Neu5Ac-(2-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp), where a third minor acetylation site was identified at the glucose residue. Disialylated species were also detected. In addition, a minor substitution of ester-linked glycine at HepIII and Kdo was observed.
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PMID:Structural analysis of the lipopolysaccharide from nontypeable Haemophilus influenzae strain 1003. 1184 82

The analgesic effects of four solutions administered intra-orally (25 and 50% sucrose solutions, hydrogenated glucose, and a sterile water placebo) were tested in groups of babies receiving routine DTP (diphtheria, tetanus, and pertussis) and HIB (Haemophilus influenzae type B) injections at the first, second, or third immunization. The duration of the baby's cry during 3 min following DTP and HIB injections was measured as main outcome. For all three immunization groups, the babies receiving the placebo generally spent most time crying. For both the DTP and HIB injections, the difference between 50% sucrose and placebo was most evident in the group receiving the 3rd immunization. Intra-oral administration of the 50% sucrose solution, compared to placebo, appeared to reduce the cry response to painful experiences in babies beyond the neonatal period.
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PMID:Intra-oral administration of sweet-tasting substances and infants' crying response to immunization: a randomized, placebo-controlled trial. 1193 21


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