In the space station, many kinds of biological experiments will be performed. In order to support the experiments, it is important to have the knowledge of preservation conditions such as temperature for biological materials including microorganisms and animal cells. In this paper, we show results of our preservation tests of three Escherichia coli (E. coli) strains (H/r30R, HsSOR, NG30), of which irradiation sensitivities are different, and three animal cell lines (L5178Y, M10, C3H10T1/2). Three months preservation tests showed that -72℃ is good temperature because high survival fractions and low mutation frequencies were observed in the E. coli strains. X-ray irradiation (0 -75 Gy) at -72℃ did not affect but carbon ion beam affected survival fractions and mutation frequencies of the E. coli strains. The effects by carbon ion beam at -72℃ were much lesser than that at 4℃. For the animal cells, survival fractions, mutation frequencies and transformation efficiencies after preservation at -80℃ were similar to those in liquid nitrogen. L5178Y and M10 cells at -72℃ were more resistant to X-ray irradiation (0.5 Gy) than at room temperature. Taken together, -72℃〜-80℃ could be an ideal temperature for 3 months preservation of microorganisms and animal cells in the soace environments.
