Human cultured keratinocytes characterized by flow cytometry

Abstract

DNA repair in root tipes of Tradescantia clones 02 and 4430 was measured by velocity sedimentation of radioactively labeled DNA obtained by the lysis of rapidly isolated nuclei placed on top of alkaline sucrose gradients. In root cells of both clones, DNA single-strand breaks induced by 10 and 20 of X-rays (irradiation in air) were rapidly repaired at 22°C. 50% of the breaks were repaired within 7–10 min and 20 min in clones 02 and 4430 respectively. In both clones, breaks were induced with an efficiency of about 1 break per 80 eV.