Yeast freeze-thaw survival rates as a function of different stages in the cell cycle

Abstract

In the present study we demonstrate that the −80 °C freeze-thaw survival rate in the yeast, Saccharomyces cerevisiae, is dependent upon specific stages in the cell cycle. Samples removed from synchronous cultures at appropriate intervals during the first three consecutive synchronous cell cycles were subjected to a −80 °C freeze-thaw protocol employing 10% glycerol as a cryoprotectant. Distinct cyclic changes in the percentage of viable cells in response to our freeze-thaw protocol were observed during each of the three consecutive synchronous cell generations examined. Maximum rates of survival occurred at the initiation of each new cell cycle and minimum rates of survival occurred approximately 30 min prior to each new cell cycle. These maximum and minimum rates of survival were shown to be correlated in time with maximum and minimum ratios of cellular phospholipid to membrane during each individual cell cycle.