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

AbstractAntarctic notothenioid鱼类进化出了南大洋的10 - 14在不同寻常的情况下我。它们的特征包括完全缺乏循环氧结合蛋白血红蛋白（Hb）。此外，在这个家族的16个成员中，一些物种也失去了表达氧结合和储存蛋白的能力，肌红蛋白（Mb）在心肌中。我们之前的工作已经确定Hb和/或Mb的损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相关。迄今为止，关于冰鱼线粒体结构的改变是如何影响细胞器功能的，或者更重要的是，它们是如何影响有机体水平的生理机能的，我们一无所知。对南极鱼类来说，最关键的是线粒体特征与变温动物抵御温度升高的能力有关。这个合作研究项目将解决南极海峡鱼不寻常的线粒体结构导致功能变化的假设，这些变化影响了它们承受温度升高的能力。具体而言，该研究将(1)确定冰鱼不寻常的线粒体结构是否影响功能并有助于机体热敏性；(2)确定红血和白血南极鱼的机体热耐受性差异；(3)确定调节冰鱼线粒体结构变化的分子机制。这一结果可能会使槽鱼纲冰鱼成为全球变暖对南大洋影响信号的哨兵分类群。通过与罗德岛大学ARMADA项目合作，高中生物教师参与实地工作，以及研究生教育，将实现该项目的广泛影响。

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.