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Master's Dissertation
DOI
10.11606/D.87.2012.tde-06062012-115003
Document
Author
Full name
Teiti Yagura
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2012
Supervisor
Committee
Menck, Carlos Frederico Martins (President)
Arruda Neto, Joao Dias de Toledo
Silva Neto, José Freire da
Title in Portuguese
Mecanismos de indução de lesões no DNA pela luz UVA e seus efeitos biológicos.
Keywords in Portuguese
Danos do DNA
DNA
Radiação ultravioleta
Abstract in Portuguese
Irradiamos amostras de DNA com luz UVA em diferentes condições para estudar os possíveis mecanismos envolvidos na indução de lesões de DNA por essa radiação. As lesões de DNA formadas após as irradiações foram quantificadas com enzimas de reparo de DNA que reconhecem e clivam os sítios contendo bases oxidadas e dímeros de pirimidina (CPDs). Complementando essas análises, foram realizados ensaios com anticorpos e HPLC-ED. NaCl e uma maior concentração de DNA são capazes de diminuir a indução de CPDs. Danos gerados por estresse oxidativo são inibidos na presença de azida de sódio e quelantes de metais, indicando o envolvimento de oxigênio singlete e reações de Fenton, na geração dessas lesões. Água deuterada e DNA mais concentrado aumentaram a indução de bases oxidadas. Quanto maior a quantidade de DNA irradiado, mais oxigênio singlete é formado, o que indica um possível mecanismo de fotossensibilização endógeno.
Title in English
Mechanisms of induction of DNA lesions by UVA light and its biological effects.
Keywords in English
DNA
DNA damage
Ultraviolet radiation
Abstract in English
DNA samples were irradiated with UVA light in different conditions for studying the possible mechanisms involved in the induction of DNA lesions by this radiation. DNA lesions formed after irradiation were quantified with DNA repair enzymes, which recognize and cleave the sites containing oxidized bases and pyrimidine dimers (CPDs). Complementing these analyses, tests were performed with antibodies and HPLC-ED. NaCl and more concentrated DNA are capable of reducing the induction of CPDs. Damage caused by oxidative stress is inhibited in the presence of sodium azide and metal chelators, indicating the involvement of singlet oxygen and Fenton reactions, in the generation of these lesions. Deuterated water and more concentrated DNA increased the induction of oxidized bases. The bigger the amount of irradiated DNA, the more singlet oxygen is formed, which indicates a possible endogenous photosensitization mechanism.
 
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Publishing Date
2012-07-06
 
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