Abstract
For the investigation of cryoprotective effect of glycine betaine (GB) on the nematode Caenorhabditis elegans and the Antarctic nematode Panagrolaimus davidi, we observed the freezing behavior and examined survival rate after freeze-thawing of the nematodes. When the nematode P. davidi was cooled slowly to -75℃ in the presence of GB (0.2 M - 1.0 M), most nematodes remained unfrozen and survived after thawing. However, when the nematodes were quenched with liquid nitrogen from -75℃, damaged nematodes were observed after thawing and survival rates were decreased. In the case of nematode C. elegans that was cooled slowly, percentage of the unfrozen nematodes and the survival rate after thawing increased as the GB concentration increased to 1.0 M. While the Antarctic nematode P. davidi was quenched by dipping into LN_2 from ambient temperature, the cryoprotective effect of GB was observed. When they dipped in 1.0 M GB were quenched with a cryo-plate, 73% of nematodes could survive after thawing. Thus, it was clear that GB has a cryoprotective effect on the nematodes.
