STUDY OF THE BIOLOGICAL EFFECTS OF AMERICIUM 241 ALPHA PARTICLES ON D7 AND RAD 54.3 STRAINS OF YEAST CELLS;

No Thumbnail Available
Date
1998-03
Authors
OKOSI, PAULINUS
NSIKAK
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Two strains of yeast cells, the D7 Saccharomyces cerevisiae and Rad 54-3 -(showing temperature repair sensitivity) were irradiated with Americium 241 alpha particles installed in two irradiation geometry. This study investigates the biological effects of Americium 241 alpha particles emerging from these two irradiation geometry on the selected strains of yeast cells with reference to the survival pattern of the two strains after alpha particle irradiation and mutation phenomenon. Mutation and survival assay for the D7 Saccharomyces cerevisiae strain and survival assay under repair permissive (23°C) and restrictive (36°C) for the Rad-54-3 strain were carried out. Mutants from the D7 yeast cell strain screened for mitotic crossing over, leading to gene conversions and reversions were selected on synthetic complete (SC) medium containing marker amino salts after three to four days post-irradiation incubation period, and the mutant frequency was calculated.. Temperature-sensitive yeast cell strain- Rad 54-3 showing temperature-dependent repair, was assayed for survival after irradiation with alpha particles from 48 MBq source and screened for survivors on full nutrient (Agar) medium under incubation in repair permissive (23°C) and restrictive (36°C) temperatures for four to five days. Results show over 90% reduction in survival fraction for the D7 yeast cells after irradiation with alpha particle fluence of 1.513 x 109 particles cm"2. Comparative' data from the X-ray irradiations yielded a D0 of 180.7Gy for same strain. There exist a clear distinction in the survival of this strain at the two incubation temperatures with the following inactivation cross-section:- 36°c = 1-34 urn2; and <j23*c = 0.74 urn2
Description
A Thesis submitted to the Post-Graduate School,Ahmadu Bello University, Zaria in partial fulfilment of the requirements for the award of the degree of Master of Science (M.Sc.) in Radiation - Biophysics DEPARTMENT OF PHYSICS FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY(ABU) ZARIA; - NIGERIA
Keywords
Citation
Collections