[Genetic effects of the decay in Saccharomyces cerevisiae yeast cells of the radionuclide products of nuclear fuel fission. II. Lethal mutagenic effects and the nature of mutations induced by an equilibrium mixture of 90Sr-90Y and 89Sr].

The lethal and mutagenic effects and the nature of mutations induced by 90Sr-90Y and 89Sr in cells of the yeast Saccharomyces cerevisiae were studied. The lethal efficiency was determined for 89Sr as (7,6 +/- 1,05) X 10(-5) decay-1, for 90Sr-90Y-(3,3 +/- 1,6) X 10(-4) decay-1. The mutagenic efficiency for ade1 and ade2 genes was determined for 89Sr as (8,3 +/- 2,5) X 10(-9) decay-1, for 90Sr-90Y-(2,9 +/- 1,5) X 10(-8) decay-1. For ade2 locus, the spectrum of mutations induced by 89Sr was a follows: one deletion, 17% of frameshifts and 83% of base pair substitutions--51% of transversions, 22% of GC-AT transitions and 10% of AT-GC transitions. The data of the present work suggest that 90Sr-90Y and 89Sr are very efficient physical mutagens. The relative mutagenic efficiency (RME) was estimated for radionuclides studied.