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)

By a direct assay approach, mutants of Haemophilus influenzae Rd that are deficient in adenosine 5'-triphosphate-dependent deoxyribonuclease activity (add-) were isolated and characterized. A large proportion (50 to 90%) of the cells in cultures of these mutants failed to produce visible colonies when plated. An extensive analysis of the recombination proficiency of these strains revealed that the transformation frequency (transformants per competent cell) in the mutants was similar to that found in the wild type, but that the transformation efficiency (transformants per microgram of irreversibly bound deoxyribonucleic acid [DNA]) was reduced approximately fourfold. Sensitivities of the mutants to gamma rays, ultraviolet radiation, and methyl methane sulfonate were only slightly greater than wild-type levels. The rate of degradation of host DNA after ultraviolet irradiation was significantly reduced in the mutants. It is suggested that the adenosine 5'-triphosphate-dependent deoxyribonuclease in H. influenzae plays a nonessential role in DNA recombination and repair.
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PMID:Isolation and characterization of mutants of Haemophilus influenzae deficient in an adenosine 5'-triphosphate-dependent deoxyribonuclease activity. 16 69

An endonuclease purified from Hemophilus influenzae made single strand breaks in DNA containing apurinic or apyrimidinic sites but had no detectable endonuclease activity on untreated native DNA. The new 5'-termini created at the cleavage sites were base-free deoxyribose 5-phosphate residues. The enzyme preparation also catalyzed the exonucleolytic release of 5'-mononucleotides from bihelical DNA and the hydrolysis of DNA 3'-terminal phosphomonoesters. The phosphatase-exonuclease activity was indistinguishable from that reported by Gunther and Goodgal (J. Biol. Chem. (1970) 245, 5341-5349) and resembled that of exonuclease III of Escherichia coli. The endonucleolytic and exonucleolytic activities could not be separated by electrophoresis, sedimentation, or gel filtration, and they were also affected simultaneously by mutation. The enzymatic activities appear to be functions of a single monomeric protein (M(r) = 30,000).
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PMID:A DNase for apurinic/apyrimidinic sites associated with exonuclease III of Hemophilus influenzae. 30 19

A number of ampicillin-resistant strains of Haemophilus influenzae could donate a gene specifying the type IIIa (TEM) beta-lactamase to Haemophilus parainfluenzae, Escherichia coli, and Pseudomonas aeruginosa. Donor strains rapidly lost their ability to transfer ampicillin resistance on storage or subculture. Such strains also apparently contained a single species of covalently closed circular deoxyribonucleic acid of contour length 1.2 mum, equivalent to about 2.5 x 10(6) daltons. No species of plasmid deoxyribonucleic acid large enough to encode sex factor activity was detected. Despite this, transfer occurred to several bacterial genera in the presence of deoxyribonuclease, suggesting that transmissibility was by conjugation. The beta-lactamase gene was generally unstable after transfer and was lost in the absence of selection. Where stable transcipients were found, this was evidently by insertion of the beta-lactamase gene into the host chromosome. In P. aeruginosa insertion was always accompanied by induction of auxotrophy for adenine, suggesting insertion at a specific site. It is believed that insertion also occurred at one site on the chromosome of Escherichia coli. Crypticity measurements for beta-lactamase activity showed that there was little or no penetration barrier to beta-lactam drugs in Haemophilus. This may explain the long delay in the acquisition of ampicillin resistance by this organism.
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PMID:Transfer of a plasmid-specified beta-lactamase gene from Haemophilus influenzae. 40 56

During bacteriophage studies on Haemophilus influenzer, it was observed that encapsulated type b and unencapsulated Rb strains released a bactericidal substance acitve against types a, c, d, e, and f H. influenzae, non-typable H. influenzae strains, other Haemophilus species, and certain members of the Enterobacteriaceae. The bactericidal activity was assayed by a plaque test utilizing an Rd strain as an indicator lawn and was also demonstrated in mixed broth cultures of a producer strain and an indicator strain. Immediately lysis of sensitive bacteria by the factor was not evident. The factor is sensitive to trypsin but resistant to deoxyribonuclease, treatment with 2-mercaptoethanol, lipase, alpha-amylase, and heating in a 100 degrees C water bath for 20 min. The activity is not dependent upon increased Ca2+ or Mg2+ concentration as is necessary for HP1C1 and S2 phage propagation. The bactericidal factor is not pelleted by high-speed centrifugation at 150,000 X g for 6 h. Treatment with ultraviolet light or mitomycin C does not result in observable phage, phage-like particles, or increased bactericidal activity. T-HE BACTERICIDAL FACTOR IS NOT A TYPICAL SMALL MOLECULAR WEIGHT "COLICIN-LIKE" BACTERiocin in that it is not inducible, has a wider range of activity, and does not kill by "single-hit" kinetics. On preliminary characterization, it is a thermostable protein toxic to certain bacterial strains.
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PMID:Bactericidal substance produced by Haemophilus influenzae b. 108 28

A transformation-deficient strain of Haemophilus influenzae, lacking adenosine 5'-triphosphate-dependent deoxyribonuclease activity, was isolated by selection for sensitivity to mitomycin. The mutant, designated JK57, possibily showed a moderate sensitivity to ultraviolet (UV) irradiation and treatment with methyl methane sulfonate. Contrary to the wild type, the mutant degraded chromosomal deoxyribonucleic acid (DNA) to some extent. However, after UV irradiation to the mutant degraded considerably less DNA than the wild type and the TD24 mutant of H. influenzae, the latter being equivalent to a recA mutant of Escherichia coli. A TD2457 double mutant, constructed by transferring the TD24 mutation into the JK57 strain, was as sensitive to deleterious agents and as deficient in transformation as the TD24 single mutant; in the double mutant, however, after UV irradiation chromosomal DNA was degraded to the same extent as in the JK57 mutant. The number of transformants per unit of radioactive donor DNA taken up by JK57 recipient cells was approximately 10-fold smaller than in the wild type. Presynaptically, the fate of donor DNA in the adenosine 5'-triphosphate-dependent deoxyribonuclease-deficient mutants was not different from that in the wild type. In contrast to TD24 and the TD2457 double mutant, in the JK57 mutant, recombinant-type activities (molecules carrying both the donor and recipient markers) were formed almost as well as in the wild type. After integration into the JK57 recipient genome, the rate of replication of the donor marker was equal to that of the recipient marker during a number of generations, which suggests that the donor DNA is normally integrated into the JK57 chromosome. It is suggested that transformed JK57 cells pass with a high frequency into a type of cells that can replicate their chromosomes many times but have lost the ability to form visible colonies after plating.
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PMID:Effect of adenosine 5'-triphosphate-dependent deoxyribonuclease deficiency on properties and transformation of Haemophilus influenzae strains. 108 3

We previously demonstrated that pneumococcal extracts contain a highly specific inhibitor of human neutrophil elastase (HNE). We now show that the active inhibitor in these extracts is a high-molecular-weight, heat-stable substance that appears to be RNA, since inhibitory activity of pneumococcal extracts is decreased by incubation with ribonuclease but not by incubation with deoxyribonuclease or proteinase K. Moreover, metabolically labeled ([3H]uridine) pneumococcal RNA, isolated by phenol extraction followed by ethanol precipitation, strongly inhibits HNE. Pneumococcal capsular polysaccharide, although polyanionic, is only weakly inhibitory toward HNE and is not a major source of elastase-inhibitory activity in pneumococcal extracts. On the other hand, the capsule of Haemophilus influenzae type b contains polyribosylribitol phosphate. This highly charged polyanion possesses HNE-inhibitory activity, but only under special circumstances to be discussed below. Pneumococci (type I, type II smooth, type II rough) and H. influenzae (type b) all release HNE-inhibitory activity into their culture medium during growth. By contrast, Klebsiella pneumoniae and Staphylococcus aureus release little (if any) stable HNE-inhibitory activity during growth. We propose that some bacterial pneumonias may spare host tissue because polyanions released by the invading microorganisms (e.g. RNA from autolysing pneumococci) inhibit elastase released from inflammatory neutrophils and thereby modulate accompanying tissue proteolysis. Pneumonias caused by microorganisms that do not release stable polyanionic inhibitors of HNE (e.g., Staphylococcus and Klebsiella) may be correspondingly more injurious to the lung.
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PMID:Inhibition of human neutrophil elastase by bacterial polyanions. 244 47

The restriction endonucleases, Hin P1 I1), Hin S1 I and Hin S2 I are isolated from three strains of Haemophilus influenzae respectively. By polymin P treatment, ammonium sulphate, precipitation and column chromatography on phosphocellulose and on heparin-Sepharose Hin P1 I is partially purified. No contaminating deoxyribonuclease activities have been detected in this purified enzyme preparation. The fact that the digestion patterns of Hin P2 I and Hha I on phage lambda, plasmids ColE1 an pBR 322 DNAs are identical that they are isoschizomers but theri splitting sites are different. The banding patterns of Hin S1 I and Hin S2 I are also the same as that of Hha I.
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PMID:Restriction endonucleases from three strains of Haemophilus influenzae. 626 7