Recovery of Ultra-Violet-irradiated L Strain Cells by means of Highly Polymerized Deoxyribonucleic Acid

Abstract

IT is known that ultra-violet irradiation may produce death of mammalian S₃ HeLa strain cells^1,2, strain D–98 and D–98C₆b (ref. 3) and L strain⁴. In our previous work we found that the rate of synthesis of nucleic acids in irradiated L strain cells is much slower than in normal cells⁴. A similar phenomenon has been observed in ultra-violet-irradiated bacteria^5,6. It is probable that some of the most important radiation effects are closely related to the damage of structure and function in nucleic acid (NA) macromolecules, which may be responsible for the modification of the genetic make-up of the cells and for their death. Therefore, the problem of the repair of this damage is one of the most important in radiobiology. Thus, we have paid special attention to the problem of the recovery of irradiated organisms, investigating the macromolecular basis of the phenomena. For this purpose, irradiated cells were treated with highly polymerized isologous deoxyribonucleic acid (DNA), and results presented in this communication show that the irradiated cells survive better if they are treated after irradiation.