2008 年 54 巻 2 号 p. 177-180
For the establishment of successful cryopreservation of Caenorhabditis elegans, freezing survival of the nematode was investigated in the presence of dimethylsulfoxide. When nematodes were cooled to -20 ℃ with the rate of 0.2 ℃/min after ice seeding treatment at -3 ℃, survival rate of the nematode increased with the time of exposure to the DMSO solution before freezing. The rate was above 80% irrespective of the cooling temperature between -20 to -75 ℃. However, the nematodes hardly survived when they were quenched by liquid nitrogen after the pre-freezing at -20 ℃, The rate of freezing survival became higher with the decrease in the pre-freezing temperature before plunging into LN_2. Heating rate also affected freezing survival. Slow heating probably prevented rapid rehydration of the nematode and increased survival rate after thawing.