Collaborative Research: Linkages among Mitochondrial Form, Function and Thermal Tolerance of Antarctic Notothenioid Fishes

摘要南极无尾类鱼类在一组不寻常的环境下在南大洋进化了10-14年。它们的特征包括完全缺乏循环中的氧结合蛋白，即血红蛋白(Hb)，在三叉鱼(Icefish)类中完全没有。此外，该家族16个成员中的一些物种也失去了在心肌中表达氧结合和储存蛋白肌红蛋白(Mb)的能力。我们以前的工作已经确定，Hb和/或Mb的丢失与氧化组织中线粒体密度的显著增加以及这些重要细胞器的广泛重塑有关。到目前为止，关于冰鱼线粒体结构的改变如何影响细胞器功能，或者更重要的是，它们如何影响生物体水平的生理学，人们还一无所知。对于南极鱼类来说，最关键的是线粒体的特征与外温动物抵御温度上升的能力有关。这一合作研究项目将解决这样一种假设，即南极棘鱼科不寻常的线粒体结构导致了功能变化，影响了它们抵御气温上升的能力。具体地说，这项研究将(1)确定冰鱼不寻常的线粒体结构是否影响功能并导致生物的热敏感性，(2)确定红血和白血的三叉戟在生物耐热性方面的差异，(3)确定调控冰鱼线粒体结构变化的分子机制。这一结果可能会建立起渠道类冰鱼作为哨兵分类群，发出全球变暖对南大洋影响的信号。该项目的广泛影响将通过与罗德岛大学的ARMADA项目以及研究生教育合作，让高中生物教师参与实地工作来实现。

AbstractAntarctic notothenioid fishes have evolved in the Southern Ocean for 10-14 MY under an unusual set of circumstances. Their characteristics include the complete absence of the circulating oxygen-binding protein, hemoglobin (Hb) within the Channichthyid (Icefish) family of notothenioids. Moreover, some species within the 16 members of this family have also lost the ability to express the oxygen-binding and storage protein, myoglobin (Mb) in cardiac muscle. Our previous work has determined that the loss of Hb and/or Mb is correlated with significant increases in densities of mitochondria within oxidative tissues, and extensive remodeling of these vital organelles. To date, nothing is known about how modifications in mitochondrial architecture of icefishes affect organelle function, or more importantly, how they affect organismal-level physiology. Most critical for Antarctic fishes is that mitochondrial characteristics have been linked to how well ectotherms can withstand increases in temperature. This collaborative research project will address the hypothesis that the unusual mitochondrial architecture of Antarctic Channichthyids has led to changes in function that impact their ability to withstand elevations in temperature. Specifically, the research will (1) determine if the unusual mitochondrial architecture of icefishes affects function and contributes to organismal thermal sensitivity, (2) identify differences in organismal thermal tolerance between red- and white- blooded notothenioids, (3) identify molecular mechanisms regulating changes in mitochondrial structure in icefishes. The results may establish channichthyid icefishes as a sentinel taxon for signaling the impact of global warming on the Southern Ocean. Broad impacts of this project will be realized by participation of high school biology teachers in field work through cooperation with the ARMADA project at the University of Rhode Island, as well as graduate education.