老衰したニホンベニクラゲ(ヒドロ虫綱, 花クラゲ目)の若返り

Abstract

Rejuvenation is induced by body damage by means of needle sticking of senile female and male medusae of Turritopsis sp. (Hydrozoa, Anthomedusae) collected from Shirahama, Wakayama Prefecture, Japan. As a result, stolon-extention rejuvenation took place in both species (60, 40%, n = 5 respectively), but zooid-formation rejuvenation rate is very low (10 %, n = 10). This rate is lower than that of very young medusa (83.3%, n = 12) from the same locality, suggesting that senile individuals are difficult to accomplish a complete rejuvenation.

和歌山県白浜産のニホンベニクラゲ（ヒドロ虫綱，花クラゲ目）の老衰した雌雄5個体ずつを針で突いて体に損傷を与えて若返りが起こるか調べた．その結果，雌雄はそれぞれ60%と40%の率で若返りを示したが，個虫まで形成できたのはわずか10％（n = 10）であった．完全な若返りは，同じ白浜産のごく若いクラゲの若返り率(83.3%, n = 12)より相当低かったことから，老衰個体は若返りを実行し難いことが示唆された.