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Results for “DEOXYRIBONUCLEASE”

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At least 109 records · Page 6Linked to original sources
PubMed1977

A DNA polymerase from Ustilago maydis. Evidence of proof-reading by the associated 3' leads to 5' deoxyribonuclease activity.

The 3' leads to 5' deoxyribonuclease activity associated with an Ustilago maydis DNA polymerase hydrolysed non-complementary 3'-primer termini about 12 times more rapidly than complementary termini. An analysis of its substrate specificity suggested that, although it was unable to hydrolyse fully single-stranded polynucleotides, it could hydrolyse such regions less than about four nucleotides in length covalently bound to a primer molecule which was base-paired to a complementary template strand. Template-primer combinations containing complementary or non-complementary primer termini both supported polynucleotide synthesis, but whereas the former were conserved, the latter were hydrolysed during the reaction thus allowing synthesis to occur. No addition of nucleotides onto a conserved non-complementary 3'-primer terminus was detected. The deoxyribonuclease activity therefore fulfilled a proof-reading function during DNA synthesis in vitro.

Basidiomycota↗
PubMed2000

A bacterial toxin that controls cell cycle progression as a deoxyribonuclease I-like protein.

Many bacterial pathogens encode a multisubunit toxin, termed cytolethal distending toxin (CDT), that induces cell cycle arrest, cytoplasm distention, and, eventually, chromatin fragmentation and cell death. In one such pathogen, Campylobacter jejuni, one of the subunits of this toxin, CdtB, was shown to exhibit features of type I deoxyribonucleases. Transient expression of this subunit in cultured cells caused marked chromatin disruption. Microinjection of low amounts of CdtB induced cytoplasmic distention and cell cycle arrest. CdtB mutants with substitutions in residues equivalent to those required for catalysis or magnesium binding in type I deoxyribonucleases did not cause chromatin disruption. CDT holotoxin containing these mutant forms of CdtB did not induce morphological changes or cell cycle arrest.

Amino Acid Sequence↗
PubMed1969

Micro test for streptococcal anti-deoxyribonuclease B.

A methyl green decolorization micro test for the determination of streptococcal anti-deoxyribonuclease B titers in serum is described. The micro test was compared with an alcohol precipitation macro test on 112 human sera. The anti-deoxyribonuclease B titers agreed within one dilution step for 85.7% of the 112 sera examined by both techniques. Both tests were about equal in the detection of titers above the upper limits of normal. The micro test requires smaller amounts of reagents and fewer man-hours to perform than the macro test. This translates into lower cost per test and more tests per man-hour.

Antibodies↗
PubMed1969

Improved medium for detecting deoxyribonuclease-producing bacteria.

Incorporation of methyl green dye into an agar medium containing deoxyribo-nucleic acid results in an improved medium for detecting deoxyribonuclease-producing bacteria. Use of the dye makes it unnecessary to use acid to demonstrate deoxyribonuclease activity, thus allowing subculture or reincubation of colonies. The improved medium is highly sensitive and can be used for primary isolation of Staphylococcus aureus or group A Streptococcus pyogenes.

Bacteria↗
PubMed1973

Toxinogeny in Corynebacterium diphtheriae after loss of catalase, cystinase, or deoxyribonuclease activity.

The relationship of catalase, cystinase, and deoxyribonuclease activity to toxinogeny in Corynebacterium diphtheriae was examined. Mutants deficient in each activity were isolated after mutagenization of strain C4 with nitrosoguanidine. All mutants were converted to toxinogeny after lysogenization with beta-converting phage, thus establishing that there is no absolute link between toxin production and these enzymatic activities. No differences were observed in the rate of lysogenization of the mutants by beta-converting phage over that of the parental strain. However, the data suggest that catalase mutants lysogenic for beta phage are generally induced at a higher rate than the parental strain after irradiation with ultraviolet light. Cystinase mutants vary widely in their rate of induction whereas the deoxyribonuclease mutants are similar to the parental strain. The relationship of these results to the production of toxinogenic strains is discussed.

Bacteriological Techniques↗
PubMed1970

Mutants of Diplococcus pneumoniae that lack deoxyribonucleases and other activities possibly pertinent to genetic transformation.

Mutants of Diplococcus pneumoniae that lacked the two major deoxyribonucleases of the cell-one an endonuclease, the other an exonuclease preferentially active on native deoxyribonucleic acid (DNA)-were obtained. The development of a method for detecting mutant colonies, based on the binding of methyl green to DNA, facilitated isolation of the mutants. Neither enzyme was essential for growth of the cells, for repair of ultraviolet damage, or for any phase of DNA-mediated transformation. Residual deoxyribonuclease activity in the double mutant corresponded to an exonuclease, approximately one-fifth as active as the major exonuclease, that attacked native and denatured DNA equally well. This activity appeared to be associated with the DNA-polymerase enzyme. A mutant that apparently lacked a cell wall lytic enzyme was also fully transformable. A mutant strain that was four times more sensitive to ultraviolet light than the wild type also transformed normally. Recipient cells of this strain were deficient in the repair of ultraviolet-irradiated transforming DNA. Mutants were found which, unlike the wild type, integrated donor markers only with high efficiency, thereby indicating that a particular cellular component that is susceptible to loss by mutation, such as an enzyme, is responsible for low integration efficiency.

Cell Wall↗
PubMed1975

Isolation and characterization of mutants of Haemophilus influenzae deficient in an adenosine 5'-triphosphate-dependent deoxyribonuclease activity.

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.

Adenosine Triphosphate↗
PubMed1975

Membrane location of a deoxyribonuclease implicated in the genetic transformation of Diplococcus pneumoniae.

The cellular localization of enzymes in Diplococcus pneumoniae was examined by fractionation of spheroplasts. A deoxyribonuclease implicated in the entry of deoxyribonucleic acid (DNA) into the cell during genetic transformation was located in the cell membrane. This enzyme, the major endonuclease of the cell (endonuclease I), which is necessary for the conversion of donor DNA to single strands inside the cell and oligonucleotides outside, thus could act at the cell surface. Another enzyme, the cell wall lysin (autolysin), was also found in the membrane fraction. Other enzymes, including amylomaltase, two exonucleases, and adenosine triphosphate-dependent deoxyribonuclease, and a restriction type endonuclease, were located in the cytosol within the cell. None of the enzymes examined were predominantly periplasmic in location. Spheroplasts were obtained spontaneously on incubation of pneumococcal cells in concentrated sugar solutions. The autolytic enzyme appears to be involved in this process. Cells that were physiologically competent to take up DNA formed osmotically sensitive spheroplasts two to three times faster than cells that were not in the competent state. Although some genetically incompetent mutants also formed spheroplasts more slowly, other such mutants formed them at the faster rate.

Cell Fractionation↗
PubMed1976

Purification and properties of two deoxyribonucleases of Pseudomonas aeruginosa.

A survey of the major deoxyribonucleases in Pseudomonas aeruginosa strain PAO was undertaken. Two activities predominated in Brij-58 lysates of this organism. These have been purified from contaminating nuclease activities, and some of their properties have been elucidated. The first was a nuclease that degraded heat-denatured deoxyribonucleic acid (DNA) to mono- and dinucleotides. The activity of this enzyme was confined to single-stranded DNA, and 100% of the substrate was hydrolyzed to acid-soluble material. The Mg2+ optimum is low (1 to 3mM), and the molecular weight is 6 X 10(4). The second predominant activity was an adenosine 5'-triphosphate (ATP)-dependent deoxyribonuclease. This enzyme had an absolute dependence on the presence of ATP Mg2+ concentrations of approximately 10 mM. Five moles of ATP was consumed for each mole of phosphodiester bonds cleaved. The acid-soluble products of the reaction consisted of short oligonucleotides from one to six bases in length. Only 50% of the double-stranded DNA was rendered acid soluble in a limit digest. The molecular weight of this enzyme is 3 X 10(5). The observation of these enzymes in P. aeruginosa is consistent with the possibility that recombinational pathways similar to those of Escherichia coli are operating in this organism.

Adenosine Triphosphate↗
PubMed1976

Effect of adenosine 5'-triphosphate-dependent deoxyribonuclease deficiency on properties and transformation of Haemophilus influenzae strains.

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.

Adenosine Triphosphate↗
PubMed1962

Evaluation of extracellular deoxyribonuclease activity in Pseudomonas.

Streitfeld, Murray M. (University of Miami, Coral Gables, Fla.), Edward M. Hoffmann, and Herbert M. Janklow. Evaluation of extracellular deoxyribonuclease activity in Pseudomonas. J. Bacteriol. 84:77-80. 1962.-Of 23 strains of P. aeruginosa isolated from pathological processes, 22 strains, representative of at least nine different somatic antigen types, were found to elaborate extracellular deoxyribonuclease. Qualitative determinations of enzyme elaboration were performed after the development of a convenient toluidine-blue assay plate procedure, dependent upon the metachromatic properties of the dye. This new procedure permits the determination of enzyme activity despite the presence, in the deoxyribonucleic acid-containing agar medium, of 2 to 5 ml/100 ml serum or plasma, or extracellular pyocyanin.

Culture Media↗
PubMed1976

Deoxyribonuclease: detection with a three-hour test.

A three-hour test has been developed to determine deoxyribonuclease activity of Enterobacteriaceae and staphylococci. The test is inexpensive and easy to perform. The rapid deoxyribonuclease test and the conventional method showed complete agreement with the strains tested.

Deoxyribonucleases↗
PubMed1978

The major fraction of deoxyribonuclease activity from human urinary proteins. Purification and properties.

The major fraction of deoxyribonuclease activity from human urinary protein was purified 40-fold in about 14% yield. The enzyme shows an isoelectric point at pH 4.2 and has a molecular weight of 33,600+/-3,000. Optimum activity was shown at pH 6.8 in the presence of 12.5 mmol/l Mg2+ plus 1 mmol/l Ca2+. The enzymic reaction is inhibited by high ionic strength (greater than 300 mmol/l Na+). The purified enzyme readily hydrolyzes native DNA to oligodeoxyribonucleotides with an average chain length of 5.3+/-0.2 after exhaustive digestion. Therefore, this endonuclease may be designated as neutral deoxyribonuclease (deoxyribonucleate oligonucleotidohydrolase, EC 3.1.4.5).

Deoxyribonucleases↗
PubMedDate not supplied

Deoxyribonucleases in herpes simplex virus type 1 and 2 infected primary rabbit kidney cells.

In primary rabbit kidney cells infected with herpes simplex virus four different neutral deoxyribonuclease activities can be detected by means of the deoxyribonuclease assay in DNA-containing polyacrylamide gels following their separation by disc-electrophoresis. The method is suitable to follow independently the change in each activity of the different enzymes using only about 5 X 10(5) cells for each assay during the time-course of infection. Under these conditions one enzyme activity is constant, two disappear while the activity of a fourth one present only in infected cells, increases.

Animals↗
PubMed1997

Deoxyribonuclease treatment improves the homogeneity of single-stranded DNA preparations.

The isolation of single-stranded (ss) phagemid DNA using standard protocols often results in impure preparations, which contain undesirable quantities of chromosomal and/or double-stranded (ds) phagemid DNA. Here we report a simple and efficient method for elimination of virtually all dsDNA by incubation of phagemid viral particles with deoxyribonuclease I. In addition to analyzing the ratio of linear-to-circular topological forms of ssDNA after deoxyribonuclease I treatment, we verified that no decrease in transformation efficiency occurred and demonstrated that ssDNA molecules covered by capsid proteins remained intact following such treatment.

Bacteriophages↗
PubMedDate not supplied

[BME 361 I--a new site-specific deoxyribonuclease type II from Bacillus megaterium 361].

Bme 361 I, a new site-specific type II deoxyribonuclease, was purified from Bacillus megaterium 361 by chromatography on phosphocellulose P 11 and hydroxylapatite. The enzyme recognizes and cleaves the nucleotide sequence 5'-GG decreases CC-3' in double-strand DNA. Thus it is a true isoschizomer of deoxyribonucleases Hae III and BspR I.

Autoradiography↗
PubMed1990

A protocol for the purification of bovine serum albumin free of deoxyribonuclease activity.

Bovine serum albumin, free of deoxyribonuclease activity, was obtained in our laboratory using ion-exchange chromatography followed by acetylation. Chromatography on four different resins (DEAE-52, P-11, hydroxylapatite and Q Sepharose fast-flow) was examined. Fractions from Q Sepharose chromatography, eluted with a linear gradient 0-1.0 M NaCl and subsequently acetylated, proved to be the most effective method for obtaining deoxyribonuclease-free bovine serum albumin.

Acetylation↗