Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.25.1 (deoxyribonuclease)
1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Low concentrations of formaldehyde (0,035 mg/m3) exert injurious effect on the testes. Changes were found in the RNA and DNA content, inhibition of deoxyribonuclease activity and reduced soluble protein content in testicular homogenate. Along with this, there was decrease in spermatozoid motility, indicating eventual weakening of the fecundating capacity of male rats. The parameters used, characterizing nuclein and protein metabolism in the testes, may serve as objective and very sensitive index in testing the gonadotoxic effect of low concentrations of chemical agents. The results of this study should be taken into consideration in making hygiene-toxicologic characteristics of formaldehyde, with special reverence to the threshold of its gonadotoxic effect.
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PMID:[Changes in protein and nucleic acid metabolism as 1 of the methods for evaluating gonadotoxic action]. 57 46

Association of foreign DNA with chicken sperm cells was investigated using a 32P-oligolabelled plasmid preparation. Significant, although low, levels of trichloroacetic acid precipitable radioactivity became rapidly associated with viable sperm cells, in contrast to the situation with formaldehyde-fixed cells. However, analysis by Southern blotting and hybridization of sperm cells incubated with an unlabelled plasmid preparation followed by deoxyribonuclease 1 treatment, demonstrated associated foreign DNA was completely susceptible to nuclease degradation, whereas chromosomal DNA was not affected.
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PMID:Uptake and deoxyribonuclease 1 susceptibility of foreign deoxyribonucleic acid by chicken sperm cells. 236 75

In this report we describe a specific staining procedure for detection of ribonucleic acid (RNA), based on bromination of uracil and subsequent immunohistochemical visualization of 5-bromouracil in RNA. This method is applicable for both cryostat and glycol methacrylate (GMA)-embedded sections. Cryostat sections must be fixed in formaldehyde, whereas tissue pieces to be embedded in GMA are fixed in cold acetone. Before bromination, sections must be treated with trypsin. Bromination was performed in a solution of bromine in potassium bromide. After bromination, excess bromine was removed with sodium bisulfite. The monoclonal antibody MoBu-1 specifically bound to brominated RNA. Ribonuclease digestion, in contrast to deoxyribonuclease digestion, abolished staining. This method makes possible precise localization of RNA, especially well demonstrated in plastic-embedded sections.
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PMID:Specific demonstration of ribonucleic acid by chemical bromination and immunohistochemistry. 246 88

Aldehyde-fixed rat tissues were variously dehydrated and impregnated in water-miscible 2-hydroxypropyl methacrylate (HPMA) containing 3 to 20 per cent water and 0.1 per cent alpha,alpha-azobisisobutyronitrile as catalyst for subsequent polymerization with ultraviolet light. Heat polymerization was also effective. Blocks of embedded tissue readily gave ultrathin sections, which required staining by uranyl acetate and/or lead stains to give adequate contrast for electron microscopy. The ultrastructure of pancreas, kidney, muscle, and intestine was well preserved by aldehyde fixation alone. Use of postfixation in osmium tetroxide or direct osmium tetroxide fixation was unsatisfactory. The fine structure of aldehyde-fixed liver from fasted rats was well preserved, whereas that from normal rats showed considerable disorganization and collapse, apparently because of extraction of glycogen during the embedding procedure. Enzymatic extraction of proteins by pepsin and of ribonucleic acid by ribonuclease after either formaldehyde or glutaraldehyde fixation was rapidly effected by direct treatment of ultrathin sections with solutions of the enzymes. In contrast, no digestion of chromatin by deoxyribonuclease could be detected. In spite of this present limitation, HPMA appears to have several advantages over earlier water-miscible embedding media for electron microscopy and to be particularly suitable for ultrastructural cytochemistry.
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PMID:Hydroxypropyl methacrylate, a new water-miscible embedding medium for electron microscopy. 585 16

Randall, Charles C. (University of Mississippi, Jackson), Lanelle G. Gafford, Richard L. Soehner, and James M. Hyde. Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior. J. Bacteriol. 91:95-100. 1966.-Deoxyribonucleic acid (DNA) was extracted from fowlpox virus-infected tissue, purified inclusions, and purified virus by five variations of detergent and phenol methods. Phenol methods gave a poor yield, whereas detergent techniques extracted up to 78% of the DNA. The buoyant density was 1.695 g/ml, and the melting temperature in 7.2 m NaClO(4) was 39 C, both approximately equivalent to a guanine plus cytosine content of 35 moles per cent. Further proof of the double-stranded nature of the DNA was shown by the characteristic behavior toward deoxyribonuclease, formaldehyde, and heat. Infectious DNA was obtained by the various methods described, but this manifestation of biological activity was capricious and for unknown reasons was often not evident. The infectivity could not be related quantitatively to the amount of DNA employed. Furthermore, the infectious nature of fowlpox virus DNA was demonstrable only when the route of infection was the chorioallantoic membrane. In contrast, whole virus infected both membrane and chick skin with equal efficiency.
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PMID:Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior. 590 15

The interphase nucleolus in Allium porrum, as in many of the plant species studied so far, is highly heterogeneous in ultrastructure owing to the presence of coarse, contorted, thread-like structures, or nucleolonemata. Each nucleolonema appears to be sharply twisted and to give rise to a skein within the nucleolar mass. In order to characterize further these nucleolar components, a variety of cytochemical techniques were exploited. For that purpose, specimens were mostly fixed in 4% formaldehyde and stained in the block according to procedures known to reveal the presence of nucleic acids or proteins. Certain specimens were also digested with deoxyribonuclease, ribonuclease or proteinase K before staining. By staining with phosphotungstic acid or bismuth oxynitrate, the presence of a high concentration of proteins can be demonstrated within thin (0.15 micrometer), filamentous structures which are believed to correspond to the outer region of the nucleolonema. Such convoluted formations disappear upon sufficiently long extraction with proteinase K. Using Bernhard's regressive staining technique for chromatin, the distribution of this substance throughout the nucleolar mass was found to match closely that of the nucleolonemata as revealed by several other procedures. As a last test for investigating the cytochemical make-up of the nucleolus, blocks of tissues were stained with 3,3'-diaminobenzidine, a substance known to react specifically with nucleic acids. When such specimens are digested with ribonuclease for 1 h, there persist within the nucleolus, fibrillogranular zones the localization of which is highly reminiscent of that of the nucleolonemata. Combination of ribonuclease hydrolysis with subsequent treatment with proteinase K (30 min) induces the extraction of a large proportion of the nucleolar material, the persisting loose and rather evenly distributed fibrils exhibiting a diamter of 3-5 nm. The possibility is considered that these units may correspond to chromatin fibrils although they have most likely been displaced from their original localization during the extraction procedures. Our cytochemical data suggest that, in Allium porrum, the nucleolonema is approximately 0.3 micrometer in diameter and may consist of a central axis from which chromatin loops project radially. A possible interpretation for the presence of protein-rich, 0.1 micrometer-thick, annular structures throughout the nucleolonemal skein is that the newly synthesized RNP products are accumulated transiently at the extremities of these loops before migrating to the immediately adjacent granular nucleolar zones.
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PMID:An ultracytochemical study of nucleolar organization in meristematic plant cells (Allium porrum). 615 22

Linear simian virus 40 DNA has been transcribed in vitro with wheat germ RNA polymerase II. Transcription products have been fractionated on polyacrylamide gels and several discrete sized RNA bands are seen. The RNA band pattern is affected dramatically by deoxyribonuclease treatment during RNA isolation. This is because most of the RNA synthesized is covalently linked to DNA. This linkage has been demonstrated by density analysis in formaldehyde-CsCl gradients and by incorporation of alkali-stable ribonucleotides into DNA. The linear DNA templates transcribed were generated by treatment of circular DNA with restriction enzymes which, in addition to cutting once at a single primary site, were found also to produce single strand nicks at specific secondary sites. The discrete sized RNA bands observed result from initiation at these nicks and terminated at DNA ends. There are two modes of nick-dependent initiation. In one mode the 3'-hydroxyl terminus of the DNA at a single strand nick serves as a primer for the extension of an RNA chain. In a second mode de novo initiation of an RNA chain is promoted at the nick. RNAs which are not primed initiate predominantly with GTP. The catalytic action of wheat germ RNA polymerase II is similar to that of Escherichia coli core RNA polymerase which has also been shown to synthesize primarily RNA which is covalently linked to DNA.
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PMID:Transcription of simian virus 40 DNA by wheat germ RNA polymerase II. Priming of RNA synthesis by the 3'-hydroxyl of DNA at single strand nicks. 624 89

With the availability of direct genomic footprinting techniques the study of native genomes has been greatly facilitated. This review provides an overview of the techniques involved and gives also a description of the mode of action of different DNA modifying agents which can be used for such methods. These include exonuclease III, deoxyribonuclease, DNase I, micrococcal nuclease, dimethyl sulfate, diethyl sulfate, ethyl methanesulphonate, ethylnitrosourea, diethylpyrocarbonate, bromoacetaldehyde, potassium permanganate, osmium tetroxide, methidiumpropyl-EDTA-iron(II), formaldehyde, psoralen, 1,10 phenanthroline-copper and UV light. We also describe the limitations of the currently existing techniques and give some potential developments.
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PMID:Approaches to characterize protein-DNA interactions in vivo. 843 8

The effects of proteolytic enzymes, ribonuclease, and deoxyribonuclease upon a fibrous component of chick embryo mitochondria, which was previously shown to have many fixation and staining properties characteristic of the bacterial nucleoplasm, are reported. Pepsin digestion of formaldehyde-fixed tissues removed the membranes and matrices of mitochondria, but a pepsin-resistant fibrous material remained which was heavily stained by uranyl and lead ions. Experiments on a DNA "model system" showed that DNA treated with osmium tetroxide can be depolymerized by deoxyribonuclease. Zinc ions strongly inhibited the depolymerization of DNA. Digestion of osmium tetroxide-fixed tissues (fixed only briefly) with deoxyribonuclease for 1 hour greatly reduced the Feulgen staining of the nuclei, and after 4 hours the Feulgen reaction was completely abolished. The reduction and the disappearance of the Feulgen reaction in nuclei was paralleled by partial to complete digestion of the mitochondrial fibers in the regions studied (after 1 and 4 hours, respectively), without any other obvious changes in cellular structures. When deoxyribonuclease was inhibited by the addition of zinc ions, the nuclear Feulgen reaction was not diminished, nor were the mitochondrial fibers removed. Buffer control incubations for deoxyribonuclease and ribonuclease did not alter the structure or staining properties of the mitochondrial fibers, nor did incubation with ribonuclease. The latter reaction digested the cytoplasmic and nucleolar ribosomes after a 4-hour incubation period, in parallel with the abolishment of toluidine blue staining. The results contribute further evidence that these mitochondria contain deoxyribonucleic acid.
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PMID:INTRAMITOCHONDRIAL FIBERS WITH DNA CHARACTERISTICS. II. ENZYMATIC AND OTHER HYDROLYTIC TREATMENTS. 1408 39

Transcription-coupled repair (TCR) is a sub-pathway of nucleotide excision repair that allows for the enhanced repair of the transcribed strand of active genes. A classical method to study DNA repair in vivo consists in the molecular analysis of UV-induced DNA damages at specific loci. Cells are irradiated with a defined dose of UV light leading to the formation of DNA lesions and incubated in the dark to allow repair. About 90% of the photoproducts consist of cyclobutane pyrimidine dimers, which can be cleaved by the DNA nicking activity of the T4 endonuclease V (T4endoV) repair enzyme. Strand-specific repair in a suitable restriction fragment is determined by alkaline gel electrophoresis followed by Southern blot transfer and indirect end-labeling using a single-stranded probe. Recent approaches have assessed the role of transcription factors in TCR by analyzing RNA polymerase II occupancy on a damaged template by chromatin immunoprecipitation (ChIP). Cells are treated with formaldehyde in vivo to cross-link proteins to DNA and enrichment of a protein of interest is done by subsequent immunoprecipitation. Upon reversal of the protein-DNA cross-links, the amount of coprecipitated DNA fragments can be detected by quantitative PCR. To perform ChIP on UV-damaged templates, we included an in vitro photoreactivation step prior to PCR analysis to ensure that all precipitated DNA fragments serve as substrates for the PCR reaction. Here, we provide a detailed protocol for both the DNA repair analysis and the ChIP approaches to study TCR in chromatin.
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PMID:Methods to study transcription-coupled repair in chromatin. 1938 41


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