Heavy Ion Effects on Yeast Cells: Induction of Canavanine-resistant Mutants

Abstract
The induction of forward mutations (resistance to canavanine) by heavy ion bombardment was investigated in wild type haploid yeast S. cerevisiae. Accelerated ions of Ar, Ti, Ni, Kr, Xe, Pb and U with specific energies between 1.7 and 9.25 MeV/u were obtained from the UNILAC machine at Darmstadt, West Germany. LET[linear energy transfer]-values ranged from 1200 to .apprx. 15,000 keV/.mu.m. There was no unequivocal dependence of mutation induction cross section on either LET or Z*2/.beta.2, but also a prominent influence of ion specific energy. This is explained by the action of long-ranging .delta.-electrons.