Surface Etching and DNA Damage Induced by Low-Energy Ion Irradiation in Yeast

Bio-effects of survival and etching damage on cell surface and DNA strand breaks were investigated in the yeast saccharomyces cerevisiae after exposure by nitrogen ion with an energy below 40 keV. The result showed that 16% of trehalose provided definite protection for cells against vacuum stress compared with glycerol. In contrast to vacuum control, significant morpho- logical damage and DNA strand breaks were observed, in yeast cells bombarded with low-energy nitrogen, by scanning electron microscopy （SEM） and terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling （TUNEL） immunofluorescence assays. Moreover, PI （propidium iodide） fluorescent staining indicated that cell integrity could be destroyed by ion irradiation. Cell damage eventually affected cell viability and free radicals were involved in cell damage as shown by DMSO （dimethyl sulfoxide） rescue experiment. Our primary experiments demonstrated that yeast cells can be used as an optional experimental model to study the biological effects of low energy ions and be applied to further investigate the mechanism（s） underlying the bio-effects of eukaryotic cells.