[X-ray-induced DNA degradation in Aspergillus nidulans cells. Comparative analysis of UV- and Xray-induced DNa degradation].

X-ray irradiation of Aspergillus nidulans wild strain cells from logarithmic phase of growth lead to delay of DNA synthesis. Insignificant enzymatic DNA degradation accomplished with its repair takes place. There is no direct dependence between doses of irradiation and levels of DNA degradation. Investigation of X-ray induced DNA degradation in the number of uvs-mutants has demonstrated the existence of two branches of DNA degradation: dependent and independent on external source of energy. Dependence of DNA degradation on the protein synthesis before and after irradiation was observed. It is proposed that the level of X-ray induced DNA degradation is determined by two protein systems: initiating and terminating DNA degradation. The comparative analysis of UV- and X-ray induced DNA degradation is carried out.