Comparison of the genetic activity of AF‐2 and nitrofurantoin in log and stationary phase cells of saccharomyces cerevisiae

Abstract

AbstractThe effects of nitrofurantoin and AF‐2 in stationary phase cells were compared with the effects in log phase cells. The Saccharomyces cerevisiae diploid strain D7 was used. This strain can be used to monitor lethality, gene conversion, mitotic gene recombination, and reversion. Stationary phase cells were not sensitive to nitrofurantoin, but treatment of log phase cells did result in the induction of lethality and gene conversion. Log phase cells were approximately 10 times more sensitive to the lethal effects of AF‐2 than were stationary phase cells. The AF‐2 induced increase in frequencies of gene conversion and mitotic recombination per surviving cell were similar in both log and stationary phase cells. Gene reversion was induced by AF‐2 in stationary cells, but no revertants were induced in log cells. Measurement of nitroreductase activity gave values for log phase cells which were five to sixfold greater than for stationary phase cells. The increased sensitivity of log phase cells to nitrofurans could therefore be in part due to an increased activation of these compounds. It is concluded that the use of log phase cells is optimal for the detection of induced gene conversion and recombination by nitro compounds.