title: Heavy ion action on yeast cells: inhibition of ribosomal-RNA synthesis, loss of colony forming ability and induction of mutants.
abstract: The action of heavy ions (Ar to U) accelerated to specific energies up to about 10 MeV/u (u=atomic mass unit) on different functions of yeast cells was studied. Ribosomal-RNA synthesis is inhibited according to a single-hit mechanism. Inactivation cross-sections were linearly related to the ratio of the squares of the effective charge Z* and the velocity of the ions. It is concluded from the analysis that the range of the most energetic delta-electrons is larger than previously assumed. There is no such dependence for survival and induction of mutants. In both cases cross-sections increase with the ion's specific-energy indicating an important contribution of long-range delta-electrons. The analysis shows that diploid yeast is not killed by a single-hit mechanism even by very heavy ions if the track width is too small. The relative importance of the penumbral region is even more pronounced with the more sensitive strains.
authors.affiliation: Strahlenzentrum der Justus-Liebig-Universitat, Giessen, FRG.
authors.forename: J
authors.initials: J
authors.lastname: Kiefer
authors.forename: S
authors.initials: S
authors.lastname: Rase
authors.forename: F
authors.initials: F
authors.lastname: Schopfer
authors.forename: E
authors.initials: E
authors.lastname: Schneider
authors.forename: K
authors.initials: K
authors.lastname: Weber
authors.forename: G
authors.initials: G
authors.lastname: Kraft
mesh_terms: D001128:Argon; D015169:Colony Count, Microbial; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions; D007726:Krypton; D007854:Lead; D018499:Linear Energy Transfer; D016296:Mutagenesis; D010315:Particle Accelerators; D012331:RNA, Fungal / Q000528:radiation effects*; D012335:RNA, Ribosomal / Q000096:biosynthesis* / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D014158:Transcription, Genetic / Q000528:radiation effects; D014501:Uranium; D014978:Xenon
chemical_list: D012331:RNA, Fungal; D012335:RNA, Ribosomal; D007854:Lead; D014978:Xenon; D014501:Uranium; D007726:Krypton; D001128:Argon