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)

Analysis of the subgingival microflora has recently implicated Actinobacillus (Haemophilus) actinomycetemcomitans and several black Bacteroides species in the aetiology of juvenile, adult and rapidly progressing periodontitis. Rapid bacteriological diagnosis has been hampered by the slow growth and fastidious nature of these bacteria. To construct diagnostic probes, dideoxy sequencing of the 16S rRNA molecules from A. (H.) actinomycetemcomitans, Haemophilus aphrophilus, Bacteroides gingivalis, Bacteroides intermedius subgroup II, Bacteroides asaccharolyticus and several closely related species was performed. Next, oligodeoxynucleotides, complementary to defined regions of the 16S rRNA exhibiting considerable evolutionary divergence, were synthesized for use as molecular probes. In a dot-blot hybridization assay, all strains from each of the species for which probes were constructed were correctly identified, with a detection limit of less than 5 x 10(3) organisms. No cross-hybridization to closely related species (except for H. aphrophilus and Haemophilus paraphrophilus) or contaminating bacteria was observed. Using a modified DNA/RNA hybridization technique, the detection could be performed in less than 12 h, as compared to 2-3 weeks using conventional bacteriological procedures.
J Gen Microbiol 1988 Jul
PMID:Synthetic oligodeoxynucleotide probes for the rapid detection of bacteria associated with human periodontitis. 246 76

Previous studies of Haemophilus organisms documented the importance of an NAD+-dependent malate dehydrogenase in the incomplete tricarboxylic acid cycle present in these organisms. Selective interactions occurring at the coenzyme and substrate binding sites of a purified Haemophilus influenzae malate dehydrogenase were investigated. Coenzyme-competitive inhibition by adenosine derivatives demonstrated the presence of regions in the coenzyme binding site that interacted with the adenosine and pyrophosphate moieties of the coenzyme. Positive chainlength effects in the coenzyme-competitive inhibition by aliphatic carboxylic acids indicated the presence of a hydrophobic region at this site that was close to the pyrophosphate region. Seven analogues of NAD+ that were structurally altered in either the pyridine or purine ring were evaluated as selective inhibitors of the enzyme. The three most effective inhibitors of the purified malate dehydrogenase inhibited the growth of H. influenzae when the organism was grown on a limiting concentration of NAD+.
J Gen Microbiol 1989 Feb
PMID:Site-directed inhibition of Haemophilus influenzae malate dehydrogenase. 261 81

SDS-PAGE of the outer-membrane (OM) proteins of Haemophilus parainfluenzae P205 grown under iron-sufficient conditions revealed three major proteins of 40, 37 and 13 kDa. In addition, growth under conditions of iron-restriction resulted in the expression of at least four iron-repressible OM proteins (IROMPs) of 72, 81, 88 and 90 kDa. OM proteins of 40 and 13 kDa were non-covalently associated with peptidoglycan and were resistant to digestion with trypsin. A 38 kDa peptidoglycan-associated protein, which was masked by the abundant 37 kDa protein, was also observed following tryptic digestion of whole cells or OMs. Neither the 37 kDa protein (which was heat-modifiable) nor the IROMPs were peptidoglycan-associated, and both were cleaved following treatment of whole cells with trypsin, indicating that they are exposed at the cell surface. A variety of IROMPs from five other H. parainfluenzae strains was also observed. In each strain, both the IROMPs and a major protein of 37 kDa were exposed at the cell surface.
J Gen Microbiol 1989 Feb
PMID:Characterization of the outer-membrane proteins of Haemophilus parainfluenzae expressed under iron-sufficient and iron-restricted conditions. 261 87

The growth factor requirements and other properties of two strains of avian haemophili, labelled as 'Haemophilus gallinarum' (an X- and V-factor-dependent organism) and stored since the 1940s and 1950s, were examined. Both strains were X-factor independent and V-factor dependent and possessed the typical biochemical, serological and pathological properties of H. paragallinarum. In experiments repeating the tests used in the 1930s that reported the existence of X- and V-factor-dependent avian haemophili, we found that the methodology used resulted in reference strains of H. paragallinarum (X-factor independent and V-factor dependent) appearing to be X- and V-factor dependent. It is likely that the early descriptions of the aetiological agent of infectious coryza as an X- and V-factor-dependent organism were incorrect.
J Gen Microbiol 1989 Feb
PMID:'Haemophilus gallinarum'--a re-examination. 261 88

Haemophilus influenzae type b strains isolated from children with meningitis, septicaemia and pharyngitis were studied for their ability to undergo genetic transformation by two chromosomal markers, streptomycin resistance and nalidixic acid resistance. Fifty-eight percent of the strains were non-transformable while the remaining 42% showed considerable strain variation with regard to their transformation frequencies, which ranged from 8 x 10(-4) to 1 x 10(-6). The effect of type b capsule on competence development and transformation activity was studied by comparing encapsulated strains with their non-encapsulated variants. Type b capsule did not inhibit either competence development or transforming efficiency. The lack of transformability in the majority of strains was not due to the presence of a capsule.
J Gen Microbiol 1989 Oct
PMID:Genetic transformation in encapsulated clinical isolates of Haemophilus influenzae type b. 263 71

The modification genes of Flavobacterium okeanokoites and Haemophilus galinarum have been cloned into the vector pBR322 and expressed in Escherichia coli cells. FokI methylase gene is contained on a 3.80 kb piece of F. okeanokoites DNA. Plasmid constructs carrying this fragment of DNA are resistant to digestion by FokI restriction endonuclease but are sensitive to cleavage by HindIII, EcoRI and PstI. Unmodified lambda DNA molecules, exposed in vitro to cell extracts prepared from cells habouring this plasmid, became resistant to digestion by FokI. The smallest HgaI methylase clone carries the pBR322 plasmid containing a 3.50 kb piece of H. galinarum DNA. This plasmid is resistant to digestion by HgaI. Neither the FokI nor the HgaI restriction endonuclease was detected in either clone. This is the first report of cloning modification genes whose protein products recognise asymmetric nucleotide sequences.
Mol Gen Genet 1987 Oct
PMID:Cloning of two type II methylase genes that recognise asymmetric nucleotide sequences: FokI and HgaI. 282 84

A variety of biologically important pyridine nucleotides and precursors were examined for their capacities to satisfy the V-factor requirement of 30 strains of porcine haemophili. Of the compounds tested, only NAD, NMN and nicotinamide riboside (NR) supported the growth of all strains; NADP supported the growth of only the type strain of Haemophilus parasuis. Further studies with the H. parasuis type strain and the neotype strain of H. pleuropneumoniae demonstrated that, during growth, these organisms exhibited affinities for NMN that were greater than those for NAD; the affinity of H. pleuropneumoniae for NR was similar to that for NMN, whereas H. parasuis exhibited relatively low affinity for NR. With either organism, equimolar amounts of NAD and NMN supported the production of approximately equal amounts of biomass whereas growth yields were substantially lower when NR was the pyridine nucleotide source. When either organism was grown in the presence of excess exogenous [carbonyl-14C]NAD, cessation of growth was accompanied by the apparent exhaustion of the NAD supply. Approximately 80% of the radioactivity added as [14C]NAD could be recovered as extracellular [14C]nicotinamide and the majority of the assimilated radioactive material was present intracellularly in the form of a [14C]NAD(P) pool. The results are discussed in terms of the structural features required of a pyridine compound for it to support the growth of porcine haemophili, the capacity of these organisms to compete for pyridine nucleotide sources in vivo, and possible mechanisms involved in the assimilation of such compounds.
J Gen Microbiol 1986 Mar
PMID:Defining the metabolic and growth responses of porcine haemophili to exogenous pyridine nucleotides and precursors. 294 35

The 2':3'-cyclic nucleotide phosphodiesterase:3'-nucleotidase of Haemophilus influenzae was purified from a periplasmic preparation by affinity chromatographic techniques. The enzyme-catalysed hydrolysis of 2':3'-cyclic AMP to adenosine without accumulation of the intermediate substrate 3'-AMP was demonstrated by high performance liquid chromatography. Competitive inhibition of the enzyme by a variety of nucleosides and mononucleotides indicated the presence of either purine or pyrimidine bases to be essential for selective interactions with the enzyme, and confirmed the need for a 3'-position phosphate for the functioning of mononucleotides as substrates for the enzyme. The enzyme had a molecular weight of 79 000, was stable at low temperatures and was thermally denatured at temperatures above 50 degrees C.
J Gen Microbiol 1985 Aug
PMID:Studies of the 2':3'-cyclic nucleotide phosphodiesterase of Haemophilus influenzae. 299 67

The 8 kbp plasmid pAT4 transformed Haemophilus influenzae Rd cells at low frequencies. Transformation was increased up to 100 times, however, when the recipient cells carried a DNA segment in either their chromosome or in a resident plasmid that was homologous to at least part of plasmid pAT4. Linearized plasmid DNA molecules did not transform cells without DNA homology; they efficiently transformed homology recipients, but only when the cuts had been made in the region of shared homology. In most cases examined the circular donor plasmid had been reconstituted from the transforming DNA; in some cases the reconstituted plasmid carried a mutation initially present in the recipient chromosome, provided the transforming plasmid had been linearized in the region of shared homology. Plasmid reconstitution was not observed in recA1 cells. We conclude that homology-facilitated plasmid transformation (transfer) is similar to that reported for Bacillus subtilis and Streptococcus pneumoniae.
Mol Gen Genet 1986 May
PMID:Homology-facilitated plasmid transfer in Haemophilus influenzae. 301 81

Binary suspensions of bacteria isolated from the gastric juice of achlorhydric patients were used to determine conditions which favour nitrite accumulation during nitrate reduction. Suspensions of Veillonella parvula and Haemophilus parainfluenzae accumulated nitrite during nitrate reduction in the absence of nitrite-reducing Neisseria subflava or Streptococcus sanguis. The maximum concentration of nitrite that transiently accumulated decreased predictably as the ratio of nitrite-removing bacteria to nitrite-accumulating bacteria increased. This ratio, but more importantly the bacterial density, determined the duration of nitrite accumulation. These results are correlated with the previously reported tendency of nitrite to accumulate in the gastric juice of hypogammaglobulinaemic and pernicious anaemic patients, and with the extremely high incidence of gastric cancer in the two groups.
J Gen Microbiol 1987 Jul
PMID:Nitrite accumulation during anaerobic nitrate reduction by binary suspensions of bacteria isolated from the achlorhydric stomach. 311 70


<< Previous 1 2 3 4 5 6 7 8 Next >>