The aim of this study is to define optimal experimental conditions for revealing DNA damaging effect of zeocin in Saccharomyces cerevisiae haploid strain 551 and to compare DNA susceptibility of this strain to zeocin and methylmethanesulfonate.
Two endpoints are used: survival fraction (SF) and primary-induced DSBs, measured by constant-field gel electrophoresis (CFGE). The role of both the exposure and concentration is clarified. Secondly, DSB levels induced after zeocin and MMS treatment are compared.
Concentrations corresponding to three levels of lethality are calculated: LD20 = 10µg/ml, LD37 = 35µg/ml and LD50 = 68µg/ml Zeo. No statistically significant difference is scored for doses lower than LD20. Dose–dependent decreased SF is obtained for concentrations in the range of 10–100µg/ml zeocin.
Although high statistically significant ( P < 0.001) DSBs amount is measured using different treatment time (1, 2, 3 and 4 min), no effect of exposure is found ( P > 0.05). On the other hand, testing the role of concentration, a dose-dependent increase of DSBs for concentrations in the range of 10–100µg/ml is established.
Correlation analysis data show that increased DSBs level correlates with decreased level of SF.
Approximately similar and statistically significant higher DSBs levels are found after zeocin and MMS treatment in comparison with untreated control.
Here, 1 min treatment time and concentrations higher than LD50 are reported as optimal for the induction of statistically significant DSBs, induced by zeocin in strain 551. These results would be of interest in further experiments regarding ROS contribution for DSBs generation after zeocin and MMS treatment.
Key words: double strand breaks, zeocin, Saccharomyces cerevisiae
Topic: BIOLOGY