RESUMO
Stannous chloride (SnCl(2)) and UVA induce DNA lesions through ROS. The aim of this work was to study the toxicity induced by UVA preillumination, followed by SnCl(2) treatment. E. coli BER mutants were used to identify genes which could play a role in DNA lesion repair generated by these agents. The survival assays showed (i) The nfo mutant was the most sensitive to SnCl(2); (ii) lethal synergistic effect was observed after UVA pre-illumination, plus SnCl(2) incubation, the nfo mutant being the most sensitive; (iii) wild type and nfo mutants, transformed with pBW21 plasmid (nfo(+)) had their survival increased following treatments. The alkaline agarose gel electrophoresis assays pointed that (i) UVA induced DNA breaks and fpg mutant was the most sensitive; (ii) SnCl(2)-induced DNA strand breaks were higher than those from UVA and nfo mutant had the slowest repair kinetics; (iii) UVA + SnCl(2) promoted an increase in DNA breaks than SnCl(2) and, again, nfo mutant displayed the slowest repair kinetics. In summary, Nfo protects E. coli cells against damage induced by SnCl(2) and UVA + SnCl(2).
Assuntos
Dano ao DNA/fisiologia , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/efeitos da radiação , DNA/efeitos dos fármacos , DNA/efeitos da radiação , Desoxirribonuclease IV (Fago T4-Induzido)/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli , Compostos de Estanho/administração & dosagem , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/efeitos da radiação , Especificidade da Espécie , Raios UltravioletaRESUMO
Methanolic extracts obtained from different organs of Cleome rosea, collected from its natural habitat and from in vitro-propagated plants, were submitted to in vitro biological assays. Inhibition of nitric oxide (NO) production by J774 macrophages and antioxidant effects by protecting the plasmid DNA from the SnCl(2)-induced damage were evaluated. Extracts from the stem of both origins and leaf of natural plants inhibited NO production. The plasmid DNA strand breaks induced by SnCl(2) were reduced by extracts from either leaf or stem of both sources. On the other hand, root extracts did not show any kind of effects on plasmid DNA, and presented significant toxic effects to J774 cells. The results showed that C. rosea presents medicinal potential and that the acclimatization process reduces the plant toxicity both to plasmid DNA and to J774 cells, suggesting the use of biotechnology tools to obtain elite plants as source of botanical material for pharmacological and phytochemical studies.
