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

摘要南极鱼类在一系列不寻常的环境下进化了10-14 MY。它们的特征包括完全没有循环氧结合蛋白，血红蛋白（Hb）在银鱼科（Icefish）家庭的notothenioids。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的损失与氧化组织内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。到目前为止，还不知道冰鱼线粒体结构的修改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。对南极鱼类来说，最关键的是线粒体特征与外温动物能否承受温度升高有关。这个合作研究项目将解决南极鱼类的不寻常的线粒体结构导致功能变化的假设，影响他们承受温度升高的能力。具体而言，该研究将（1）确定冰鱼的不寻常的线粒体结构是否影响功能并有助于生物体的热敏感性，（2）确定红血和白色血的notothenioids之间的生物体耐热性差异，（3）确定调节冰鱼线粒体结构变化的分子机制。这些结果可能会建立channichthyid冰鱼作为一个哨兵类群的信号对南大洋的全球变暖的影响。通过与罗得岛大学的阿尔马达项目合作，高中生物教师将参与实地工作，并开展研究生教育，从而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.