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)

A prominent iron-regulated periplasmic protein was purified from Pasteurella haemolytica grown in an iron-deficient chemically defined medium. The protein was purified by anion exchange chromatography and appeared as a single band by SDS-PAGE with a molecular weight of 32,000. A yield of five mg was obtained from 91 mg of protein extract. The iron-regulated protein existed as a monomer in the native state with an average molecular weight of 29,877 as determined by analytical ultracentrifugation. The protein had a molecular weight of 30,880 as determined by matrix-assisted laser desorption mass spectrometry, hence the protein is referred to as the 31 kDa protein. Isoelectric focusing showed four bands with pIs of 7.15, 6.8, 6.6, and 5.9. The secondary structure of the protein was determined by circular dichroism and contained 16% alpha-helical structure. The N-terminal sequence, EPFKVVTTFTVIQDIAQNVAGDKAT, showed a 95% identity with the 31 kDa iron-binding protein from Haemophilus influenzae. Isolation and characterization of iron-regulated proteins are of particular interest because of their potential roles in iron assimilation and microbial virulence.
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PMID:Purification and characterization of a 31-kilodalton iron-regulated periplasmic protein from Pasteurella haemolytica A1. 941 58

Haemophilus influenzae biogroup aegyptius, the causative agent of Brazilian purpuric fever (BPF), expresses a heat-modifiable 48 kDa outer membrane protein, P1, which is conserved in most Brazilian case-clone isolates. To study the role of P1 in pathogenesis of BPF we constructed via homologous recombination an isogenic P1-deficient mutant of H. influenzae biogroup aegyptius. The procedure involved a modification of Hererot's method for development of competence. Modifications included variations in the growth conditions, use of cAMP, specific characteristics of the donor DNA, and antibiotic selection. P1-deficient mutants were confirmed by SDS-PAGE, loss of reactivity with a specific monoclonal antibody on Western blot, restriction analysis and Southern blot. Our results establish the first successful transformation of homologous DNA into H. influenzae biogroup aegyptius.
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PMID:Creation of an isogenic P1-deficient mutant of Haemophilus influenzae biogroup aegyptius. 943 83

Thirty-eight clinical isolates of Haemophilus influenzae and ten clinical isolates of Streptococcus pneumoniae were examined for IgA1 protease production. A suspension of surface material of each individual strain was incubated with human secretory IgA; IgA1 cleavage products were detected by SDS-PAGE and immunoblotting. The high incidence of IgA1 protease-positive strains (68.4% of the examined H. influenzae and 100% of the examined S. pneumoniae strains) confirms that IgA1 protease activity is a frequent characteristic of these two species. Yet the presence of this enzyme is, if at all, only a minor decisive factor for the induction of symptomatic infections of the upper respiratory tract by IgA1 protease-positive bacteria.
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PMID:IgA1 protease production by bacteria colonizing the upper respiratory tract. 956 83

The gene (denoted aroQp.pheA) encoding the bifunctional P-protein (chorismate mutase-P/prephenate dehydratase) from Xanthomonas campestris was cloned. aroQp.pheA is essential for L-phenylalanine biosynthesis. DNA sequencing of the smallest subclone capable of functional complementation of an Escherichia coli phenylalanine auxotroph revealed a putative open reading frame (ORF) of 1200 bp that would encode a 43,438-Da protein. AroQp.PheA exhibited 51% amino acid identity with a Pseudomonas stutzeri homologoue and greater than 30% identities with AroQp.PheA proteins from Haemophilus influenzae, Neisseria gonorrhoeae, and a number of enteric bacteria. AroQp.PheA from X. campestris, when expressed in E. coli, possesses a 40-residue amino-terminal extension that is lysine-rich and that is absent in all of the AroQp.PheA homologues known at present. About 95% of AroQp.PheA was particulate and readily sedimented by low-speed centrifugation. Soluble preparations of cloned AroQp.PheA exhibited a native molecular mass of 81,000 Da, indicating that the active enzyme species is a homodimer. These preparations were unstable after purification of about 40-fold, even in the presence of glycerol, which was an effective protectant before fractionation. When AroQp.PheA was overproduced by a T7 translation vector, unusual inclusion bodies having a macromolecular structure consisting of protein fibrils were observed by electron microscopy. Insoluble protein collected at low-speed centrifugation possessed high catalytic activity. The single band obtained via SDS-PAGE was used to confirm the translational start via N-terminal amino acid sequencing. A perspective on the evolutionary relationships of monofunctional AroQ and PheA proteins and the AroQp.PheA family of proteins is presented. A serC gene located immediately upstream of X. campestris aroQp.pheA appears to reflect a conserved gene organization, and both may belong to a single transcriptional unit.
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PMID:The aroQ and pheA domains of the bifunctional P-protein from Xanthomonas campestris in a context of genomic comparison. 968 22

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen, commonly associated with otitis media and exacerbations of chronic bronchitis. Studies concerning the pathogenesis of NTHi have proposed an important function for P5, an outer membrane protein believed to play a role in the initiation of infection by mediating adherence to respiratory mucin. P5 has also generated interest as a potential vaccine candidate. In a previous study, an NTHi library screen with antibodies raised against P5 purified from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that the purified protein was contaminated with closely migrating proteins. Consequently, the aim of this study was to express P5 in a heterologous system to overcome potential contamination with NTHi proteins that may complicate analytical or vaccine studies. Recombinant P5, with an N terminal extension of 10 residues that included six histidines, was cloned and expressed in Escherichia coli. The rP5 was purified with the Talon metal affinity resin in a denatured form and then refolded by incorporation into mixed-detergent micelles of octylglucoside and SDS. Circular dichroism of the refolded rP5 demonstrated 55% beta-strand content, which is consistent with the beta-strand content of native P5 and the homologous E. coli protein OmpA.
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PMID:A method for the purification and refolding of a recombinant form of the nontypeable Haemophilus influenzae P5 outer membrane protein fused to polyhistidine. 1002 63

Phosphorylcholine is an important bioactive adduct to the teichoic acid (TA) and lipoteichoic acid (LTA) of the surface of Streptococcus pneumoniae. We have identified and characterized a genetic locus lic that is required for phosphorylcholine metabolism in S. pneumoniae. The pneumococcal lic locus consists of eight genes, licA, licB, licC and licD1, licD2 and three additional open reading frames. Pneumococcal licA, licB, licC, licD1 and licD2 have significant sequence similarity to licA, licB, licC and licD of Haemophilus influenzae. Mutation of licD2 led to decreased [3H]-choline uptake, aberrant migration of LTA chains in SDS-PAGE gels, loss of several surface proteins, and a phase-locked hypertransparent colony phenotype. Moreover, the licD2- mutant falled to undergo lysis after treatment with penicillin at high cell density and showed decreased transformation competence. Finally, the licD2- mutant demonstrated decreased adherence to the human type II alveolar cells, reduced nasopharyngeal colonization in infant rats, as well as significantly impaired virulence upon intraperitoneal challenge of CF1 mice. Identification of the lic genes in the pneumococcus will facilitate further characterization of the role of surface choline in microbial physiology and pathogenesis.
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PMID:Pneumococcal licD2 gene is involved in phosphorylcholine metabolism. 1020 Sep 66

Haemophilus influenzae is a common inhabitant of the upper respiratory tract and can cause serious infections of mucosal surfaces. Results from recent studies indicate that this pathogen possesses copious amounts of surface-localized phosphomonoesterase activity mediated by the bacterial lipoprotein e (P4). While the enzyme has previously been purified to apparent homogeneity, purification of large amounts of protein has been prevented by presence of N-terminal lipid modification. Recombinant DNA technology was employed to simultaneously replace the N-terminal lipid modification signal sequence with one for protein secretion without such modification and to place expression of the protein under the control of the T7-inducible promoter. Results from this work show that high levels of phosphomonoesterase activity were achieved after IPTG induction and purified to apparent homogeneity after two chromatography steps. Consistent with loss of the N-terminal lipid modification, the recombinant enzyme was easily extracted from the bacterial membrane and partitioned within the matrix of gel filtration chromatography resin while retaining a denatured molecular weight similar to that of wild-type e (P4). Results from physicochemical characterization suggest that the recombinant protein was similar to wild-type protein in SDS-PAGE-derived molecular weight, primary structure, substrate specificity, pH optimum, and sensitivity or resistance to various inhibitors. Acquisition of sufficient amounts of recombinant P4 was a prelude for studies to elucidate the structure and function of this unusual phosphomonoesterase.
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PMID:Purification and characterization of a recombinant Haemophilus influenzae outer membrane phosphomonoesterase e (P4). 1060 Apr 58

Lipopolysaccharides (LPSs) were purified from Actinobacillus pleuropneumoniae serotype 2, Bordetella bronchiseptica and Haemophilus parasuis serotype 5, which were used for vaccine production in Japan, by the phenol-water procedure. In SDS-PAGE analysis, A. pleuropneumoniae LPS, as well as Escherichia coli LPS, demonstrated a typical ladder profile of a smooth-type LPS. On the other hand, B. bronchiseptica and H. parasuis LPSs lacked the ladder profiles. It was found that the biological activity of these LPSs was comparable to those of E. coli LPS in terms of activation of the clotting enzyme of Limulus amoebocyte lysate, mitogenic activity of mouse spleen cells, stimulation of TNF-alpha and nitric oxide production, but IL-6 production could hardly be observed in any LPS.
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PMID:Biological activities of lipopolysaccharides extracted from porcine vaccine strains. 1065 Oct 44

Diverse organisms ranging from Escherichia coli to humans contain a variety of DNA repair proteins that function in the removal of damage caused by shortwave UV light. This study reports the identification, purification, and biochemical characterization of two DNA glycosylases with associated abasic lyase activity from Neisseria mucosa. These enzymes, pyrimidine dimer glycosylase I and II (Nmu-pdg I and Nmu-pdg II), were purified 30,000- and 10,000-fold, respectively. SDS-polyacrylamide gel electrophoresis analysis indicated that Nmu-pdg I is approximately 30 kDa, whereas Nmu-pdg II is approximately 19 kDa. The N-terminal amino acid sequence of Nmu-pdg II exhibits 64 and 66% identity with E. coli and Hemophilus parainfluenzae endonuclease III, respectively. Both Nmu-pdg I and Nmu-pdg II were found to have broad substrate specificities, as evidenced by their ability to incise DNA containing many types of UV and some types of oxidative damage. Consistent with other glycosylase/abasic lyases, the existence of a covalent enzyme-DNA complex could be demonstrated for both Nmu-pdg I and II when reactions were carried out in the presence of sodium borohydride. These data indicate the involvement of an amino group in the catalytic reaction mechanism of both enzymes.
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PMID:Two glycosylase/abasic lyases from Neisseria mucosa that initiate DNA repair at sites of UV-induced photoproducts. 1080 6

A search of the gonococcal genome database using the known zinc-binding protein (znuA) sequences from Escherichia coli and Haemophilus influenzae identified an open reading frame encoding a putative gonococcal ZnuA. The consensus amino acid sequence of this open reading frame possessed a characteristic 30-amino acid histidine-rich metal-binding motif (repetitive HDH sequence) containing 43% histidine and 37% aspartic acid and glutamic acid. Subsequently, two adjacent open reading frames with homology to E. coli and H. influenzae znuB and znuC were located upstream of znuA. When partially purified from sonicated cell-free supernatants by CM-Sepharose chromatography, the mature gonococcal ZnuA had an estimated molecular mass of 38 kDa by SDS-PAGE. The presence of a DNA sequence encoding a 19-amino acid signal peptide and the solubility of the mature ZnuA suggested that this protein was located in the periplasm. Inactivation of the Neisseria gonorrhoeae F62 znuA by insertional mutagenesis resulted in a mutant that had a growth rate lower than that of the wild-type parent strain and that required high concentrations of ZnCl2 (> or = 200 microM) for optimal growth. Using a chemically defined agar medium, the gonococcal ZnuA mutant grew only in the presence of Zn(2+), whereas Mg(2+), Ca(2+), Ni(2+), Fe(2+), Cu(2+), Mn(2+) and Cd(2+) had either no effect or were growth inhibitory.
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PMID:Identification and characterization of a high-affinity zinc uptake system in Neisseria gonorrhoeae. 1150 9


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