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)

The Haemophilus-Neisseria identification (HNID) panel (American MicroScan, Sacramento, Calif.) is a 4-h microdilution format system for identification of Haemophilus and Neisseria spp., Branhamella (Moraxella) catarrhalis, and Gardnerella vaginalis. The HNID panel was evaluated by using 423 clinical isolates and stock strains of these organisms, and HNID identifications were compared with those obtained by conventional methods. In addition, 32 isolates representing six genera not included in the HNID data base were tested to determine whether these organisms would produce unique biotype numbers for possible inclusion in the data base. The HNID panel correctly identified 95.3% of 86 Neisseria gonorrhoeae strains, 96% of 25 G. vaginalis strains, and 100% of 28 Neisseria lactamica strains and 48 B. catarrhalis strains. Only 64.7% of 68 Neisseria meningitidis isolates were identified correctly owing to false-negative or equivocal carbohydrate and/or aminopeptidase reactions. Among the Haemophilus spp., 98.8% of 83 H. influenzae strains, 97.1% of 34 H. parainfluenzae strains, and 80% of 15 H. aphrophilus and H. paraphrophilus strains were correctly identified. Eight strains of Neisseria cinerea, a species not included in the data base, produced profiles identical with those for B. catarrhalis and N. gonorrhoeae. Isolates of other species not included in the data base, including Eikenella corrodens, Kingella spp., and Cardiobacterium hominis, produced unique biochemical reaction patterns on the panel. Modification of interpretative criteria for certain tests, expansion of the data base to include other species, and suggestions for additional confirmatory tests will increase the accuracy and utility of the HNID panel.
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PMID:Identification of Neisseria spp., Haemophilus spp., and other fastidious gram-negative bacteria with the MicroScan Haemophilus-Neisseria identification panel. 250 51

Protease and peptidase enzymes are thought to play a role in the virulence of many oral organisms, especially those associated with periodontal diseases. In order to evaluate the peptidases of periodontopathogens, we compared the arylaminopeptidase activities of Bacteroides gingivalis with those of other oral and non-oral bacteria. Sixty-three bacterial strains representing the prominent cultivable organisms in human periodontal pockets were tested, including representatives of the black-pigmented Bacteroides, Actinobacillus, Actinomyces, Campylobacter, Capnocytophaga, Eikenella, Fusobacterium, Haemophilus, Lactobacillus, Streptococcus, and Veillonella species. Each micro-organism was examined for its ability to hydrolyze 18 synthetic substrates of beta-naphthylamide derivatives of amino acids, dipeptides, and tripeptides. Quantitation of the enzyme activity was accomplished by colorimetric measurement of the amounts of released beta-naphthylamines. N-CBz-glycyl-glycyl-L-arginine-beta-naphthylamide was readily cleaved by B. gingivalis, but slightly or not at all by the other oral strains tested. L-arginine-beta-naphthylamide was cleaved by B. gingivalis, Capnocytophaga species, and Streptococcus species, but not readily by the other Bacteroides strains. Some dipeptide substrates tested, such as glycyl-L-arginine- and glycyl-L-proline-beta-naphthylamide, were strongly cleaved by B. gingivalis and weakly cleaved by other Bacteroides strains. Since high levels of N-CBz-glycyl-glycyl-L-arginyl-aminopeptidase activity are characteristic of B. gingivalis, its measurement may be valuable in the identification of this organism in clinical samples as an aid in diagnosis and monitoring of periodontal infections. Furthermore, this and other aminopeptidases produced by B. gingivalis and other oral organisms may play a role in the tissue destruction seen in periodontal disease.
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PMID:Arylaminopeptidase activities of oral bacteria. 347 93

The API ZYM system (Analytab Products, Plainview, N.Y.), containing 19 chromogenic substrates, was utilized semiquantitatively to detect extracellular acid and alkaline phosphatases, aminopeptidases, proteases, esterase-lipase, phosphoamidase, and glycosidases in 128 oral and nonoral isolates of black-pigmented Bacteroides, Actinobacillus, Haemophilus aphrophilus, Capnocytophaga, Fusobacterium nucleatum, Wolinella recta, and Veillonella parvula. In the black-pigmented Bacteroides group of organisms, a strong trypsin reaction was present in Bacteroides gingivalis (oral species) but not in Bacteroides asaccharolyticus (nonoral species). Bacteroides melaninogenicus subsp. melaninogenicus, in contrast to Bacteroides melaninogenicus subsp. intermedius, exhibited strong N-acetyl-beta-glucosaminidase activity. H. aphrophilus produced beta-galactosidase and alpha-glucosidase, but the closely related Actinobacillus actinomycetemcomitans did not. Capnocytophaga was distinct with respect to strong aminopeptidase reactions. This study showed that a wide range of enzymes which have the potential of causing tissue injury and inflammation can be elaborated from major oral gram-negative species. Also, the API ZYM system appears to be a valuable adjunct to traditional biochemical testing in identifying oral gram-negative species.
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PMID:Enzymatic characterization of some oral and nonoral gram-negative bacteria with the API ZYM system. 702 98

Haemophilus influenzae produces surface structures called pili that promote adherence to human cells. Three genes encoding the major pilus structural component (pilin), chaperone, and usher proteins (designated hifA, -B, and -C, respectively) have been identified previously. In this study, transposon mutagenesis and DNA sequence analysis identified two open reading frames (ORFs) downstream of, and in the same orientation as, hifC. These genes have been designated hifD and hifE. Both genes have predicted C-terminal amino acid homology to HifA, and mutations in either gene resulted in the loss of morphologic and functional pili, indicating that hifD and hifE encode pilus structural components and are required for pilus expression. Another ORF, identified immediately downstream of hifE, has a predicted amino acid sequence that is 70% identical to an aminopeptidase of Escherichia coli called PepN, and a mutation within this ORF did not alter pilus expression. These data indicate that the pepN homolog is not required for pilus biogenesis and that one end of the pilus gene cluster has been defined.
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PMID:Identification of hifD and hifE in the pilus gene cluster of Haemophilus influenzae type b strain Eagan. 792 73

The properties of an aminopeptidase (AP) from Fusobacterium nucleatum were studied in view of the fact that this organism, along with other Gram-negative anaerobes involved in periodontal diseases, survives in the subgingival environment by obtaining energy via the fermentation of a small number of peptide-derived amino acids. The AP was found to be cell-associated and was isolated from disrupted chemostat-grown cells. It was purified by (NH4)2SO4 fractionation, two column chromatographic steps and IEF. The enzyme was found to have a molecular mass of 54 kDa, a pI of 5.1, a pH optimum between 7.5 and 8.0 and, using Leu-Ala as substrate, it gave K(m) and Vmax values of 0.66 mM and 0.12 mumol min-1 mg-1, respectively. No complete homology was found between the N-terminal sequence of the first 20 amino acids (MDXKXYVDLKERFLRYVKFN...) and any other published sequence, but residues 8-20 gave a 62% match with residues 9-21 of an AP from Haemophilus influenzae. The enzyme was inactivated by chelating agents, bestatin, p-hydroxymercuribenzoate and some heavy metals. Cobalt ions restored EDTA-inactivated activity but did not reverse inhibition by 1,10-phenanthroline. In addition, bestatin and 1,10-phenanthroline had an inhibitory effect on the batch growth of F. nucleatum in a complex medium in which peptidase activities would be nutritionally essential. No such inhibition was observed in a chemically defined medium in which growth was not dependent upon peptidase activities. The peptidase described in this paper therefore appears to be a cobalt-activated metallo-AP which, together with other peptidases, is considered to be important in the survival of F. nucleatum in the subgingival environment of the mouth.
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PMID:An aminopeptidase nutritionally important to Fusobacterium nucleatum. 969 13

The amino acid sequence analysis of the human and porcine aminoacylases-1, the carboxypeptidase S precursor from Saccharomyces cerevisiae, the succinyl-diaminopimelate desuccinylase from Escherichia coli, Haemophilus influenzae and Corynebacterium glutamicum, the acetylornithine deacetylase from Escherichia coli and Dictyostelium discoideum and the carboxypeptidase G(2) precursor from Pseudomonas strain, using the Basic Local Alignment Search Tool (BLAST) and the Position-Specific Iterated BLAST (PSI-BLAST), allowed us to suggest that all these enzymes, which share common functional and biochemical features, belong to the same structural family. The three amino acid blocks which were found to be highly conserved, using the CLUSTAL W program, could be assigned to the catalytic active site, based on the general three-dimensional structure of the carboxypeptidase G(2) from the Pseudomonas strain precursor. Six additional proteins with the same signature have been retrieved after performing two successive PSI-BLAST iterations using the sequence of the conserved motif, namely Lactobacillus delbrueckii aminoacyl-histidine dipeptidase, Streptomyces griseus aminopeptidase, Saccharomyces cerevisiae aminopeptidase Y precursor, two Bacillus stearothermophilus N-carbamyl-L-amino acid amidohydrolases and Pseudomonas sp. hydantoin utilization protein C. The three conserved amino acid motifs corresponded to the following blocks: (i) [S, G, A]-H-x-D-x-V; (ii) G-x-x-D; and (iii) x-E-E. This new sequence signature is clearly different from that commonly reported in the literature for proteins belonging to the ArgE/DapE/CPG2/YscS family.
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PMID:Sequence analysis of the aminoacylase-1 family. A new proposed signature for metalloexopeptidases. 1125 May 42

The catalytic and structural properties of divalent metal ion cofactor binding sites in the dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae were investigated. Co(II)-substituted DapE enzyme was 25% more active than the Zn(II)-loaded form of the enzyme. Interestingly, Mn(II) can activate DapE, but only to approximately 20% of the Zn(II)-loaded enzyme. The order of the observed k(cat) values are Co(II) > Zn(II) > Cd(II) > Mn(II) >Ni(II) approximately equal Cu(II) approximately equal Mg(II). DapE was shown to only hydrolyze L,L-N-succinyl-diaminopimelic acid (L,L-SDAP) and was inactive toward D,L-, L,D-, and D,D-SDAP. DapE was also inactive toward several acetylated amino acids as well as D,L-succinyl aminopimelate, which differs from the natural substrate, L,L-SDAP, by the absence of the amine group on the amino acid side chain. These data imply that the carboxylate of the succinyl moiety and the amine form important interactions with the active site of DapE. The affinity of DapE for one versus two Zn(II) ions differs by nearly 2.2 x 10(3) times (K(d1) = 0.14 microM vs K(d2) = 300 microM). In addition, an Arrhenius plot was constructed from k(cat) values measured between 16 and 35 degrees C and was linear over this temperature range. The activation energy for [ZnZn(DapE)] was found to be 31 kJ/mol with the remaining thermodynamic parameters calculated at 25 degrees C being DeltaG(++) = 64 kJ/mol, DeltaH(++) = 28.5 kJ/mol, and DeltaS(++) = -119 J mol(-1) K(-1). Electronic absorption and EPR spectra of [Co_(DapE)] and [CoCo(DapE)] indicate that the first Co(II) binding site is five-coordinate, while the second site is octahedral. In addition, any spin-spin interaction between the two Co(II) ions in [CoCo(DapE)] is very weak. The kinetic and spectroscopic data presented herein suggest that the DapE from H. influenzae has similar divalent metal binding properties to the aminopeptidase from Aeromonas proteolytica (AAP), and the observed divalent metal ion binding properties are discussed with respect to their catalytic roles in SDAP hydrolysis.
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PMID:Substrate specificity, metal binding properties, and spectroscopic characterization of the DapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Haemophilus influenzae. 1296

The catalytic and structural properties of the H67A and H349A dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae were investigated. On the basis of sequence alignment with the carboxypeptidase from Pseudomonas sp. strain RS-16, both H67 and H349 were predicted to be Zn(II) ligands. The H67A DapE enzyme exhibited a decreased catalytic efficiency (180-fold) compared with wild-type (WT) DapE towards N-succinyldiaminopimelic acid. No catalytic activity was observed for H349A under the experimental conditions used. The electronic paramagnetic resonance (EPR) and electronic absorption data indicate that the Co(II) ion bound to H349A-DapE is analogous to that of WT DapE after the addition of a single Co(II) ion. The addition of 1 equiv of Co(II) to H67A DapE provides spectra that are very different from those of the first Co(II) binding site of the WT enzyme, but that are similar to those of the second binding site. The EPR and electronic absorption data, in conjunction with the kinetic data, are consistent with the assignment of H67 and H349 as active-site metal ligands for the DapE from H. influenzae. Furthermore, the data suggest that H67 is a ligand in the first metal binding site, while H349 resides in the second metal binding site. A three-dimensional homology structure of the DapE from H. influenzae was generated using the X-ray crystal structure of the DapE from Neisseria meningitidis as a template and superimposed on the structure of the aminopeptidase from Aeromonas proteolytica (AAP). This homology structure confirms the assignment of H67 and H349 as active-site ligands. The superimposition of the homology model of DapE with the dizinc(II) structure of AAP indicates that within 4.0 A of the Zn(II) binding sites of AAP all of the amino acid residues of DapE are nearly identical.
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PMID:The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Haemophilus influenzae contains two active-site histidine residues. 1871 20