The Effect of Cryoprotective Agents on the Survival of Tetrahymena pyriformis

Abstract

The effects of penetrating and non-penetrating cryoprotective agents on the survival of the ciliate Tetrahymena pyriformis were studied. Tetrahymena cells were gradually frozen, rapidly thawed and reconstituted. Percent cell survival and motility were recorded for each of the cryoprotective agents used, namely, glycerol, ethylene glycol and dimethyl sulfoxide as penetrating agents and trehalose and sucrose as non-penetrating agents. One-way ANOVA and Tukey’s test were performed for statistical analysis. Highest survival was recorded in 10% glycerol (38.39%) and 11.1 trehalose (30.95%) treatments. However, a greater percentage of motile cells (8.33%) was recorded in 5% DMSO than in any other treatment. In addition, the size of DNA fragments from cells treated with 10% glycerol and 1.1 M trehalose were relatively similar to those of untreated cells, whereas DNA fragments from cells of the control group were damaged. SEM images of the T. pyriformis cells treated with 10% glycerol and 1.1 M trehalose resembled those cells under normal conditions. In the control group, the cell membrane ruptured and instead of pyriform, the cell as elongated. Statistical analysis showed that the means of difference concentrations of various cryoprotective agents were significantly different from each other.