Potential Association between Insulin-like Growth Factor-1 Receptor Activity and Surf Clam Spisula sachalinensis Larvae Survival

We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M di-methyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrifica-tion. After immersion into VSs and freezing, IGF-1R β-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular β-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability. Key words: Spisula sachalinensis , Surf clam, D-shaped larvae, Umbo larvae, Vitrification, IGF-1R Introduction A number of attempts to develop a cryopreservation pro-cess in mammals and aquatic organisms have been made. Al-though vitrification is appealing because of its simplicity, it faces the challenges of intra/extracellular ice formation and the toxicity of high concentrations of cryoprotective agents. Recently, methods for vitrification of fish embryos, including zebrafish (