[Radiosensitivity of the nucleus and mitochondrion of the yeast cell: a study by cytoduction].

We have crossed irradiated and unirradiated genetically marked haploid yeast cells and studied the influence of gamma-irradiation on the yield of nuclear-cytoplasmic haploid hybrids (cytoductants). In the first cross, the cytoductants possessed the irradiated cytoplasm (mitochondrions) and unirradiated nuclei, in the second cross they possessed the irradiated nuclei and unirradiated mitochondria. After irradiation of nuclei, the yield of cytoductants dropped sharply in relation to doses of radiation. In contrast to this, no mitochondrion damage was observed after doses from 0 to 2000 Gy. A small number of cytoductants appeared after 8160 Gy applied to mitochondrion. We may suggest that the nuclear damage is the only cause of the cell inactivation after irradiation using doses up to 2000 Gy.