RESUMO
The work offers an "in vivo-in vitro" model which allows to identify DNA's both structural and functional damages caused by gamma-irradiation in doses from 0.02 to 0.25 Gy. As a donor the authors used an irradiated pTTQ 19 plasmide which had two marker genes: the ampicilline-resistant gene (amp(r)) and beta-galactosidase structural gene (lacZ alpha). E. coli GM 109 bacterial stamm transformed by the irradiated plasmide was used as a recipient. The structural damages of the irradiated plasmide were registered by DNA electrophoretic analysis in agarose gel. The plasmide DNA dysfunctions were assessed by its ability to pass on ampicilline resistance to E. coli bacterial cells as well as by beta-galactosidase level. The irradiated plasmide was found to have a tendency to decrease beta-galactosidase activity and number of E. coli ampicilline-resistant transformants depending on the received radiation dose: by 24.5% (0.05 Gy), 30.9% (0.19 Gy), and by 40.2% (0.25 Gy).
