Pyrimidine Dimers
Mostrando 1-12 de 350 artigos, teses e dissertações.
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1. "Photo" Chemistry Without Light?
In the early seventies, Giuseppe Cilento (São Paulo University), Emil White (Johns Hopkins University) and Angelo Lamola (AT&T Bell Laboratories) postulated that typical photochemical reactions could occur in dark parts of living organisms if coupled to enzymatic sources of electronically excited products. Their paradoxical hypothesis of "photochemistry wit
J. Braz. Chem. Soc.. Publicado em: 2015-12
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2. Plasmid DNA damage induced by singlet molecular oxygen released from the naphthalene endoperoxide DHPNO2 and photoactivated methylene blue
To investigate oxidative lesions and strand breaks induction by singlet molecular oxygen (¹O2), supercoiled-DNA plasmid was treated with thermo-dissociated DHPNO2 and photoactivated-methylene blue. DNA lesions were detected by Fpg that cleaves DNA at certain oxidized bases, and T4-endoV, which cleaves DNA at cyclobutane pyrimidine dimers and apurinic/apyrim
Química Nova. Publicado em: 2010
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3. Papel biológico dos dímeros de pirimidina em células humanas irradiadas com radiação UVA / Biological role of pyrimidine dimers in human cells irradiated with UVA radiation
A radiação ultravioleta (UV) pode ser absorvida por diferentes moléculas celulares, incluindo o DNA no qual provoca distorções estruturais. As lesões mais comuns induzidas pela radiação UV são o ciclobutano de pirimidina (CPD) e o fotoproduto (6-4)-pirimidina-pirimidona [(6-4)PPs]. Estas lesões podem ser reparadas pela fotorreativação, caracteriz
Publicado em: 2010
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4. Caracterização funcional de componentes da resposta ao dano DNA em Aspergillus nidulans: os genes chkA, chkB e ddbA / Functional Characterization of DNA damage response components in Aspergillus nidulans: the ddbA, chkA and chkB genes.
The constant exposure of different organisms to agents that damage the DNA structure, has provided the cells with repair mechanisms that are conserved during evolution. In mammal cells, the DNA damage repair pathways and the cell cycle checkpoint regulation act together to prevent cell cycle progression before the repair is performed avoiding mutation fixaxi
Publicado em: 2007
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5. Determination of Pyrimidine Dimers in Escherichia coli and Cryptosporidium parvum during UV Light Inactivation, Photoreactivation, and Dark Repair
UV inactivation, photoreactivation, and dark repair of Escherichia coli and Cryptosporidium parvum were investigated with the endonuclease sensitive site (ESS) assay, which can determine UV-induced pyrimidine dimers in the genomic DNA of microorganisms. In a 99.9% inactivation of E. coli, high correlation was observed between the dose of UV irradiation and t
American Society for Microbiology.
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6. Photoreactivation and dark repair of ultraviolet light-induced pyrimidine dimers in chloroplast DNA.
A UV-specific endonuclease was used to detect ultraviolet light-induced pyrimidine dimers in chloroplast DNA of Chlamydomonas reinhardi that was specifically labeled with tritiated thymidine. All of the dimers induced by 100 J/m2 of 254 nm light are removed by photoreaction. Wild-type cells exposed to 50 J/m2 of UF light removed over 80% of the dimers from c
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7. Demonstration of pyrimidine dimer-DNA glycosylase activity in vivo: bacteriophage T4-infected Escherichia coli as a model system.
An approach to the detection of pyrimidine dimer-DNA glycosylase activity in living cells is presented. Mutants of Escherichia coli defective in uvr functions required for incision of UV-irradiated DNA were infected with phage T4 denV+ or denV- (defective in the T4 pyrimidine dimer-DNA glycosylase activity). In the former case the denV gene product catalyzed
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8. Repair of Uv-Induced Pyrimidine Dimers in DROSOPHILA MELANOGASTER Cells in Vitro
Tissue culture cells of Drosophila melanogaster were given various doses of ultraviolet light. The results indicate that Drosophila cells do have a dark-repair excision mechanism which is not sensitive to caffeine. Pyrimidine dimers were destroyed by photoreactivating illumination in these cells and this destruction probably represents monomerization of the
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9. Utilization of DNA photolyase, pyrimidine dimer endonucleases, and alkali hydrolysis in the analysis of aberrant ABC excinuclease incisions adjacent to UV-induced DNA photoproducts.
ABC excinuclease of Escherichia coli removes 6-4 photoproducts and pyrimidine dimers from DNA by making two single strand incisions, one 8 phosphodiester bonds 5' and another 4 or 5 phosphodiester bonds 3' to the lesion. We describe in this communication a method, which utilizes DNA photolyase from E. coli, pyrimidine dimer endonucleases from M. luteus and b
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10. Repair of Pyrimidine Dimer Damage Induced in Yeast by Ultraviolet Light
Crude extracts from ultraviolet (UV)-irradiated yeast cells compete with UV-irradiated transforming deoxyribonucleic acid (DNA) for photoreactivating enzyme. The amount of competition is taken as a measure of the level of cyclobutyl pyrimidine dimers in the yeast DNA. A calibration of the competition using UV-irradiated calf thymus DNA indicates that an inci
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11. Characteristics of excision repair of pyrimidine dimers in eukaryotic cells as assayed with anti-dimer sera.
An antiserum that recognizes the three types of pyrimidine dimers induced by UV-light in DNA was used to monitor their removal from eukaryotic cell nuclei. Cells able to excise dimers display a similar removal pattern: a fast process completed within a few hours leaving many dimers in the DNA.
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12. New role for photoreversible pyrimidine dimers in induction of prototrophic mutations in excision-deficient Escherichia coli by UV light.
UV mutagenesis to His+ in certain recA441 lexA51 bacteria was not photoreversible, indicating that pyrimidine dimers are not target lesions. Photoreversibility was observed in recA+ lexA51 bacteria, showing that pyrimidine dimers are needed to activate the recA+ protein (unlike the recA441 protein) to perform a function in UV mutagenesis distinct from cleava