The comparison of genetic instability in haploid and diploid yeast cells exposed to ionizing radiations of different linear energy transfer and ultraviolet light

• Main Authors: Ekaterina S Evstratova, Kaushala P Mishra, Vladislav G Petin
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2018-01-01
• Series: Journal of Radiation and Cancer Research
• Subjects: Alpha particles; gamma rays; genetic instability; survival; ultraviolet light; yeast cells
• Online Access: http://www.journalrcr.org/article.asp?issn=0973-0168;year=2018;volume=9;issue=2;spage=79;epage=85;aulast=Evstratova
• ISSN: 2588-9273; 2468-9203

Context: It is analyzed whether genetic instability is determined by cell ability to recover from radiation damage or it is mainly determined by cell ploidy. The values of the RBE of α-particles for cell survival and genetic instability are obtained for haploid and diploid yeast cells. The delayed appearance of clones by cells surviving after exposure to γ-rays, α-particles, and UV-light are compared. Aim: To compare of genetic instability in haploid and diploid yeast cells exposed to ionizing radiations of different LET and UV light. Materials and Methods: Haploid (strain S288C, RAD) and homozygous diploid (strain XS800, RAD/RAD) yeast cells of Saccharomyces cerevisiae were used in our experiments. Cell survival and delayed clone appearance were studied for cells surviving after exposure to 60Co γ-rays, 239Pu α-particles and 254 nm UV light. Survival was determined by cell ability to produce macrocolonies on a solid nutrient medium. Genetic instability was defined by the delayed appearance of clones by cells surviving irradiation. Results: The delayed appearance of clones by cells surviving after irradiation has been well expressed and reached about 100% for diploid strain and only 20–25% for haploid strain independently of radiation type. Both cell survival and genetic instability exhibited more pronounced manifestation after the action of alpha particles than after irradiation with gamma-rays. This effect may be associated with greater efficiency of densely ionizing radiation to produce lethal radiation damage and accompanying sub-lesions responsible for delayed appearance of clones. The dependence of this effect on cell survival was substantially the same after exposure to UV light, sparsely and densely ionizing radiation. Conclusion: The genetic instability is mainly determined by cell ploidy rather than the shape of survival curve and the ability of cell to recover from radiation damage as it is traditionally assumed for Saccharomyces cerevisiae yeast cells.