Delayed onset of adult antifreeze activity in juveniles of the Antarctic icefish Chaenocephalus aceratus

详细信息    查看全文

• 作者：Kevin T. Bilyk and Arthur L. DeVries
• 关键词：Antarctic fish ; Notothenioidei ; Channichthyidae ; Chaenocephalus aceratus ; Freeze avoidance ; Antifreeze Glycoprotein ; Development
• 刊名：Polar Biology
• 出版年：2010
• 出版时间：October 2010
• 年：2010
• 卷：33
• 期：10
• 页码：1387-1397
• 全文大小：471.6 KB

文摘

Many Antarctic notothenioid species endemic to the Seasonal Pack-ice Zone have converged on adult blood serum freezing points that are several tenths of a degree above the freezing point of seawater. While these fishes share high adult serum freezing points, the development of their freeze avoidance during ontogeny has not been studied. We investigated this in wild caught juveniles of one such species, Chaenocephalus aceratus (family Channichthyidae), using blood serum antifreeze activity as a proxy for their freeze avoidance. Juvenile serum antifreeze activity was significantly below that of adults through the oldest year 2+ specimens collected. This increased at an estimated rate of 0.368 ¡Á 10−3 ¡À 0.405 ¡Á 10−4¡ãC day−1 which, if sustained, would leave C. aceratus below their adult serum antifreeze activity levels of 0.57 ¡À 0.08¡ãC until 4.2 years after hatching. Underlying the 2.7-fold increase in their serum antifreeze activity from late year 0+ juveniles to adults was an even greater 10.4-fold increase in the concentration of their serum antifreeze glycopeptides, which increased proportionally across all of their serum AFGP size isoforms. With insufficient antifreeze activity to avoid freezing in the ice-laden surface waters, both adult and juvenile C. aceratus are most likely restricted to the year round ice-free waters where a metastable supercooled state can be maintained.