Abstract
For the investigation of cryoprotective effect of antifreeze glycoprotein (AFGP) 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 Antarctic nematode P.
davidi was cooled slowly to -75°C in the presence of 0.5% AFGP dissolved in M9 buffer, percentage of the
unfrozen nematodes increased and most of them survived after thawing. In the case of nematode C. elegans
that was cooled slowly, the nematodes in AFGP dissolved in M9 buffer could not survive though most of the
nematodes in 0.5% AFGP dissolved in 5% DMSO could survive after freeze-thawing. The cryoprotective
effect of AFGP was observed even when P. davidi was quenched by dipping it into LN2. When the
nematodes were dipped in 0.5% AFGP dissolved in 5% DMSO and quenched with a cryo-plate, 79% of them
could survive after thawing. Thus, it is clear that AFGP has cryoprotective effect on the nematodes.
