Cyclobutane
Mostrando 1-12 de 221 artigos, teses e dissertações.
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1. 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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2. Potentiometric studies on nickel(II), copper(II) and zinc(II) metal complexes with new schiff bases containing cyclobutane and thiazole groups in 60% dioxane-water mixture
Neste estudo são investigados potenciometricamente os equilíbrios ácido-base de bases de Schiff contendo ciclobutano e tiazol como grupos funcionais e de seus complexos de cobre(II), níquel(II) e zinco(II) em dioxano-água, 60% em média, a 25,0 ± 0,1 ºC e com I = 0,10 mol L-1 (NaClO4). Os valores das constantes de protonação, logK OH, logK NH(1) e l
Journal of the Brazilian Chemical Society. Publicado em: 2009
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3. Fotodimerização no estado solido : obtenção e caracterização de substancias ciclobutanicas / Photodimerization on solid state : obtaining and characterization of substances cyclobutanics
A fotodimerização de compostos orgânicos no estado sólido vem sendo utilizada como um método de síntese promissor na obtenção de substâncias ciclobutânicas. Pesquisas recentes relataram as atividades analgésicas e anticancerígenas dessas substâncias. Este trabalho teve como objetivo a obtenção de substâncias ciclobutânicas pelas fotodimeriza
Publicado em: 2008
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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. Electron collisons with cyclobutane
We report integral, differential, and momentum transfer cross sections for elastic scattering of low-energy electrons by cyclobutane (c-C4H8), which is an isomer of the C4H8 molecule and has a closed chain. Our calculations were performed with the Schwinger multichannel method with pseudopotentials at the static-exchange level of approximation, for energies
Brazilian Journal of Physics. Publicado em: 2006-06
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6. Complexos a - diiminicos de platina (II)
New complexes bis-chloro, tetrachloro and dicarboxylate (a - diiminic) platinum (II) were synthesized. The neutral ligands were the a-diiminic heterocyclic derivatives of phenantroline, 2,2 -bipyridine, tryazine and pyrazine: 2,3-bis(2-pyridil)pyrazine (DPP); 2,2 ,4 ,2",6",2" - quaterpyridine (QTPY): 2,2 - bipyridine-ketone (BPYKE); 4,4 -diphenyl-2.2 -bipyri
Publicado em: 1994
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7. Effect of intermolecular triplex formation on the yield of cyclobutane photodimers in DNA.
We have studied the effect of intermolecular triplexes formation on the yield of cyclobutane photodimers in DNA. DNA duplex within the pyrimidine-purine-pyrimidine triplex d(TC)nd(GA)nd(CT)n is protected from the formation of cyclobutane photodimers in the case of the stabilization of this triplex by acid pH, and in the case of supplementary stabilization by
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8. Antigen structural requirements for recognition by a cyclobutane thymine dimer-specific monoclonal antibody.
A monoclonal antibody (TDM-2) specific to a UV-induced cyclobutane pyrimidine dimer (T[cis-syn]T) has previously been established; however,the immunization had used UV-irradiated calf-thymus DNA containing a heterogeneous mixture of photoproduct sites. We investigated here the structural requirements of antigen recognition by the antibody using chemically sy
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9. UV light-induced cyclobutane pyrimidine dimers are mutagenic in mammalian cells.
We used a simian virus 40-based shuttle vector plasmid, pZ189, to determine the role of pyrimidine cyclobutane dimers in UV light-induced mutagenesis in monkey cells. The vector DNA was UV irradiated and then introduced into monkey cells by transfection. After replication, vector DNA was recovered from the cells and tested for mutations in its supF suppresso
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10. Ultraviolet-induced mutations in Cockayne syndrome cells are primarily caused by cyclobutane dimer photoproducts while repair of other photoproducts is normal.
We compared the contribution to mutagenesis in Cockayne syndrome (CS) cells of the major class of UV photoproducts, the cyclobutane pyrimidine dimer, to that of other DNA photoproducts by using the mutagenesis shuttle vector pZ189. Lymphoblastoid cell lines from the DNA repair-deficient disorders CS and xeroderma pigmentosum (XP) and a normal line were trans
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11. Photoproduct frequency is not the major determinant of UV base substitution hot spots or cold spots in human cells.
The role of UV radiation-induced photoproducts in initiating base substitution mutations in human cells was examined by measuring photoproduct frequency distributions and mutations in a supF tRNA gene on a shuttle vector plasmid transfected into DNA repair-deficient cells (xeroderma pigmentosum, complementation group A) and into normal cells. Frequencies of
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12. Photoreactivation of Escherichia coli reverses umuC induction by UV light.
UV mutagenesis in Escherichia coli depends on the presence of a premutagenic lesion in DNA and on the induction of the umuCD gene product as part of the SOS response. Using operon fusions between the E. coli lacZ gene and the SOS genes umuC, uvrB, and dinD, we have affirmed the expected role of the cyclobutane pyrimidine dimer in inducing SOS gene transcript