抄録
Larvae of Polypedilum vandezplanki can enter the state of cryptobiosis in which organisms are almost completely dehydrated and the metabolic activity is undetectable. One of the most characteristic phenomena is remarkable accumulation of trehalose in the cryptobiotic larva. This study aimed to clarify an importance of vitrified trehalose in cryptobiosis. Slowly-dehydrated larva (Slow sample) accumulated much trehalose, successfully entered the state of cryptobiosis, and showed high temperature tolerance, whereas quickly-dehydrated one (Quick sample) with a small amount of trehalose failed to do. Differential scanning calorimetric (DSC) analysis demonstrated that glass transition took place only in Slow sample, suggesting that a large amount of trehalose in the larval body is actually vitrified. When Slow samples were exposed to high relative humidity such as 93 or 98% for 5 days, the glassy state was lost and the recovery rate was lowered, although the trehalose content did not change so much. On the other hand, those exposed to 38% or 60% r.h. maintained the glassy state and the ability for recovery. However, their glass-transition temperatures declined, and consequently they became sensitive to high temperature. The results in the present study suggest vitrification of trehalose in the larval body is essential for induction and maintenance of cryptobiosis in P. vanderplanki.
