UMLS:C0348321 - FACTA Search

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)

116 V factor (NAD)-dependent strains belonging to the family Pasterurellaceae isolated from porcine pneumonic lungs were collected in Spain over a period of 1 yr and studied using 52 biochemical characters. In addition to Actinobacillus pleuropneumoniae (72 strains), Haemophilus taxon minor group (37 strains) and Taxon D (four strains), other taxon (three strains) were observed. This taxon, provisionally designated as Haemophilus sp. sorbitol+, is closed to A. pleuropneumoniae but differed by some biochemical characteristics. Among A. pleuropneumoniae strains, nine different serotypes were detected, the most frequent being serotypes 4 and 2.
...
PMID:Characterization of V factor-dependent organisms of the family Pasteurellaceae isolated from porcine pneumonic lungs in Spain. 831 35

Atypical Haemophilus paragallinarum have been isolated from both laying hens and broilers suffering from typical symptoms of infectious coryza in South Africa. Re-inoculation of these bacteria into SPF chickens resulted in similar pathology. The bacteria could be successfully re-isolated from the experimentally infected chickens. Four of the isolates from layers and 3 of those from broilers were found to be closely related to H. paragallinarum serotype A (0083 strain) when tested by the use of a panel of locally developed monoclonal antibodies in the enzyme linked immunosorbent assay (ELISA). A total of 15 isolates from layers and 19 from broilers were found to be more typical of previously collected South African field isolates of H. paragallinarum. A 3rd group, consisting of 5 isolates from layers and 15 from broilers, showed no reaction with the panel of monoclonal antibodies. All the isolates were regarded as atypical because they no longer required V factor (NAD) for growth, whereas strain 0083 and previously collected field isolates M 85 and SB 86 did require it. Crude plasmid extractions from an isolate serologically related to 0083 was used to convert reference strains of H. paragallinarum into NAD-independent isolates, thus indicating that NAD independence is carried on a plasmid.
...
PMID:Plasmid-encoded NAD independence in some South African isolates of Haemophilus paragallinarum. 833 25

The absolute requirement for elemental iron and the porphyrin nucleus for growth of Haemophilus influenzae led us to investigate the role of iron and hemin in regulation of expression of the H. influenzae transferrin receptor. H. influenzae type b strain H1689 was grown in brain heart infusion broth supplemented with beta-NAD and either 10 or 0.1 microgram of hemin ml-1. Transferrin-binding ability was determined with a dot blot assay using human transferrin-horseradish peroxidase conjugate. Cells grown in media with 0.1 microgram of hemin ml-1 bound transferrin, but organisms grown in media with 10 micrograms ml-1 did not. In hemin-restricted media, transferrin binding occurred despite addition of up to 10 mM ferric nitrate, ferric citrate, or ferric PPi, whereas addition of 10 micrograms of hemoglobin ml-1 repressed expression. The breadth of species distribution of this mode of regulation was determined with strains previously characterized by multilocus enzyme electrophoresis. When grown in hemin-restricted media, 24 of 28 type b strains and 52 of 57 serologically nontypeable strains exhibited transferrin binding, although none did so in hemin- and iron-sufficient media. Strain H1689 and serologically nontypeable strain HI1423 grown in heat-inactivated pooled normal human serum, human cerebrospinal fluid, or human breast milk exhibited transferrin binding. Growth in these fluids with 10 micrograms of added hemin ml-1 abolished transferrin binding, whereas addition of 10 mM ferric nitrate did not. These data suggest that the transferrin receptor of H. influenzae is regulated by levels of hemin but not elemental iron alone and that this property is widely distributed among several major cloned families in the species.
...
PMID:Expression of the Haemophilus influenzae transferrin receptor is repressible by hemin but not elemental iron alone. 840 90

Only scanty data are available on the susceptibility of Haemophilus influenzae in Italy. The in vitro activity of ampicillin, ampicillin-sulbactam, cefaclor, cefuroxime, cefotaxime, chloramphenicol, erythromycin and trimethoprim-sulfamethoxazole against 327 strains of Haemophilus influenzae (55 encapsulated, 272 non-typeable) isolated from adults and children in northern Italy, between January 1984 and December 1989, was compared. Patients were affected by meningitis or other invasive infections, conjunctivitis, otitis, sinusitis, pneumonia or bronchitis. Minimal inhibiting concentrations were determined by a microdilution technique in Mueller Hinton broth supplemented with 10 microliters/ml NAD and 2-5% lysed horse blood. A concentration of 1 x 10(5) to 5 x 10(5) CFU/ml was used as the inoculum. The antibiotics were tested at concentrations ranging from 0.03 to 64 microliters/ml with the exception of trimethoprim-sulfamethoxazole, for which the range of concentrations examined were 0.01/0.25 to 32/512 microliters/ml. All the strains tested were susceptible to ampicillin-sulbactam, cefuroxime and cefotaxime, and more than 95% were susceptible to ampicillin, cefaclor and chloramphenicol. Only 4% were susceptible to erythromycin but most minimal inhibiting concentrations fell into the intermediate category. Strains isolated from adults were more susceptible to trimethoprim-sulfamethoxazole than strains isolated from children (85% vs 66%; p = 0.011).
...
PMID:Antimicrobial resistance among clinical isolates of Haemophilus influenzae in northern Italy. Collaborative Study on Pediatric Infectious Diseases. 847 3

Infectious coryza remains an important disease in the poultry industry despite the long-term and widespread use of vaccines against its causative agent, Haemophilus paragallinarum, in South Africa. In order to detect antigenic changes between populations of H. paragallinarum isolated before the use of vaccines against infectious coryza in this country, and field isolates obtained after the introduction of infectious coryza vaccines, 106 different NAD-dependent isolates (of which 93 were identified as H. paragallinarum) from 63 different farms, and dating from 1972 to March 1995, were identified by means of rabbit antisera against serogroups A, B and C. Serogroup C isolates show weaker cross-protection, requiring the further subdivision of this serogroup into its four different serovars. The percentages of the different serovars obtained in the 1970s, confirmed previously published data on South African isolates. A tendency towards a decrease in the number of serogroup A and serovar C-2 isolates, and an increase in the percentage of serovar C-3 isolates, was noted among isolates of the 1980s. These changes were markedly enhanced in the isolates obtained from 1990 to March 1995. The percentage of serogroup A isolates decreased significantly from 34% in the 1970s to only 5% in the 1990s, and that of serovar C-2 isolates, from 31-18%, while the abundance of serovar C-3 isolates increased significantly from 31% in the 1970s to 73% in the 1990s. Serogroup B remained more or less constant and never reached more than 10% of the population. These results indicate the need for the incorporation of serovar C-3 in a vaccine for use in South Africa, particularly in those areas of the country from which isolates were collected during this study. Some of the NAD-dependent isolates obtained from poultry in South Africa between 1970 and 1995, were biochemically identified as Pasteurella avium and P. volantium. As H. avium has been subdivided and reclassified into the genus Pasteurella, this represents the first report of the identification of P. avium and P. volantium in South Africa.
...
PMID:Changes in the incidences of the different serovars of Haemophilus paragallinarum in South Africa: a possible explanation for vaccination failures. 891 59

Rat liver d-3-phosphoglycerate dehydrogenase was purified to homogeneity and digested with trypsin, and the sequences of two peptides were determined. This sequence information was used to screen a rat hepatoma cDNA library. Among 11 positive clones, two covered the whole coding sequence. The deduced amino acid sequence (533 residues; Mr 56493) shared closer similarity with Bacillus subtilis 3-phosphoglycerate dehydrogenase than with the enzymes from Escherichia coli, Haemophilus influenzae and Saccharomyces cerevisiae. In all cases the similarity was most apparent in the substrate- and NAD+-binding domains, and low or insignificant in the C-terminal domain. A corresponding 2.1 kb mRNA was present in rat tissues including kidney, brain and testis, whatever the dietary status, and also in livers of animals fed a protein-free, carbohydrate-rich diet, but not in livers of control rats, suggesting transcriptional regulation. The full-length rat 3-phosphoglycerate dehydrogenase was expressed in E. coli and purified. The recombinant enzyme and the protein purified from liver displayed hyperbolic kinetics with respect to 3-phosphoglycerate, NAD+ and NADH, but substrate inhibition by 3-phosphohydroxypyruvate was observed; this inhibition was antagonized by salts. Similar properties were observed with a truncated form of 3-phosphoglycerate dehydrogenase lacking the C-terminal domain, indicating that the latter is not implicated in substrate inhibition or in salt effects. By contrast with the bacterial enzyme, rat 3-phosphoglycerate dehydrogenase did not catalyse the reduction of 2-oxoglutarate, indicating that this enzyme is not involved in human D- or L-hydroxyglutaric aciduria.
...
PMID:Cloning, sequencing and expression of rat liver 3-phosphoglycerate dehydrogenase. 916 25

Haemophilus paragallinarum causes infectious coryza in poultry, and a panel of monoclonal antibodies (Mabs) were established, which detect surface antigens of this bacterium. It was postulated that these Mabs could be used to detect antigenic differences between strains of H. paragallinarum used in infectious coryza (IC) vaccines, and isolates made from the field, from poultry vaccinated against IC. It has previously been reported that in South Africa there are three different Mab patterns that have been common to H. paragallinarum isolates for the past three decades. The effects of different growth conditions such as duration of incubation, inoculum size, levels of NAD or NaCl in the medium, and the pH of the medium on these Mab patterns were investigated. It was found that many different factors appear to influence the expression of the antigens detected by the panel of Mabs. It was found that at different stages during the growth cycles, the isolates could be classified into different Mab groups. It was also found that alteration of the inoculum size resulted in Mab-pattern switches. Addition of extra NaCl to the medium, in order to slow the growth rate, was found to result in Mab-pattern switches. pH was found to have significant effects on the levels of expression of the antigens detected by the Mabs, although these changes did not result in Mab-pattern switches. The effects of pH were also found to be highly strain dependent. The use of NAD, rather than sterile chicken serum, in the medium did not significantly alter the levels of expression of these antigens. Alterations of the growth conditions greatly affected the levels of expression of the antigens detected by the Mabs, and were highly strain dependent. It was not possible to predict the effects of a particular growth condition on a particular strain or isolate of H. paragallinarum.
...
PMID:Effects of growth conditions and incubation times on the expression of antigens of Haemophilus paragallinarum which are detected by monoclonal antibodies. 920 5

Haemophilus parasuis malate dehydrogenase ((S)-malate:NAD+ oxidoreductase; EC 1.1.1.37) isolated from cell sonicates was purified 584-fold to electrophoretic homogeneity with a 19% recovery and a specific activity of 222 units/mg protein. SDS-polyacrylamide gel electrophoresis and molecular exclusion chromatography indicated the purified enzyme to be a dimer composed of 34,600 molecular weight subunits. Kinetic parameters for all four substrates in the forward and reverse reactions indicated a sequential mechanism for this enzymic process. Product and dead-end inhibition studies were consistent with an ordered bi-bi mechanism in which NAD is the first substrate bound to the enzyme and NADH the second product released. Protection against thermodenaturation of the enzyme by NAD and not by malate was supportive of this mechanism. A pronounced product inhibition by NADH (K(i) = 9.0 microM) was observed. Although NADP did not serve as a coenzyme, a number of analogs of NAD structurally altered in the nitrogen base moieties were observed to function as coenzymes in the oxidation of malate catalyzed by the purified malate dehydrogenase. Coenzyme-competitive inhibition of the malate dehydrogenase was observed with five adenosine derivatives and six structural analogs of NAD. Of the NAD analogs studied as inhibitors, 3-pyridylcarbinol adenine dinucleotide was the most effective (K(i) = 18 microM). Although inhibition of growth of H. parasuis by this analog was observed, it was less effective (K(i) = 136 microM) than the inhibition of the purified dehydrogenase.
...
PMID:Purification and kinetic characterization of Haemophilus parasuis malate dehydrogenase. 924 95

The periplasmic nucleotide pyrophosphatase from Haemophilus parasuis was purified 750-fold to electrophoretic homogeneity through salt fractionation and ion-exchange and affinity chromatography. The purified enzyme was monomeric with an apparent M(r) of 70,000 and catalyzed the hydrolysis of the pyrophosphate bond of NAD to yield NMN and AMP as products. The enzyme exhibited negative cooperativity in the hydrolysis of a number of pyridine dinucleotides and structurally-related pyrophosphate compounds as indicated by biphasic double-reciprocal plots and Hill coefficients of 0.5. The kinetic parameters, K(m) and Vm, determined titrimetrically and analyzed through computer programs, were used to compare the relative effectiveness of dinucleotides containing nitrogen bases other than nicotinamide or adenine to that of NAD. Effective substrate-competitive inhibition of the pyrophosphatase was observed with purine and pyrimidine nucleoside diphosphates in the low micromolar concentration range. Although less effective, N1-alkylnicotinamide chlorides also inhibited competitively with respect to the substrate, NAD. In addition to being an effective inhibitor of the purified enzyme, adenosine diphosphate also inhibited growth of H. parasuis at a low micromolar concentration. This inhibition of growth correlates well with inhibition of the periplasmic pyrophosphatase which is supported by the fact that adenosine diphosphate does not effectively inhibit growth when the pyrophosphatase is by-passed by growth on nicotinamide mononucleotide. These observations are all consistent with the periplasmic nucleotide pyrophosphatase being essential for the growth of the organism on NAD and therefore, a very important enzyme with respect to the pathogenesis of the organism. 3-Aminopyridine mononucleotide, which also inhibited growth of H. parasuis at a low micromolar concentration, did not effectively inhibit the purified pyrophosphatase and a different target enzyme needs to be considered to explain growth inhibition by this derivative.
...
PMID:Characterization of H. parasuis periplasmic nucleotide pyrophosphatase as a potential target enzyme for inhibition of growth. 945 36

Azithromycin has in vitro activity which includes important respiratory pathogens and is successful in treatment of respiratory tract infections. We assessed postantibiotic effect (PAE) of azithromycin against 3 stains of Streptococcus pneumoniae, 2 strains of Haemophilus influenzae and 2 strains of Moraxella catarrhalis. The strains were exposed for 2 hours to an azithromycin concentration of 0.5 mg/L (maximum serum concentration achieved by azithromycin after the usual dosing regimen). A stationary phase inoculum of 1 x 10(6)-5 x 10(6) UFC/ml in IsoSensitest Broth with 5% lysed horse blood and 20 mg/L NAD was used and shaken for the duration of the experiment. Antibiotic was neutralised by dilution 1:1000 into pre-warmed medium. Viable counts were determined before and after antibiotic exposure and then hourly for 7 hours by Miles and Misra method. The experiment was performed in triplicate. Even at such low concentration as that achieved in serum, azithromycin exhibits a PAE of 119 min for pneumococci, 130 min for haemophili and 155 min for moraxellae, fact which could allow the use of usual oral regimen in bacteraemic respiratory infection, as well.
...
PMID:[The postantibiotic effect of azithromycin on respiratory pathogens]. 945 50

<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>