Preservation of Toxoplasma gondii by Freezing

Publisher Website
Google Scholar
Abstract
Efforts to preserve Toxoplasma gondii by slow freezing in glycerol solutions have been successful and survival of parasites in the frozen state has been demonstrated for up to 209 days. Results of experiments varying the rate of freezing and the proportion of glycerol have indicated that very slow freezing using 5-10 percent glycerol is best. Even with the optimum methods, the initial loss of viability after freezing is great, but storage at below -70[degree]C results in little further loss of viability over the period tested. Rapid thawing for a few minutes in a water bath at 37[degree]C has been practiced. It is suggested that freezing should be a good method of preservation of strains without the cumbersome and dangerous necessity of frequent animal transfer, and this method is now being used in our laboratory. It is also suggested that the freezing method may allow the preservation of strains in their original state, unmodified by continuous rapid animal passage.
Keywords