Protein Folding and Embryogenesis in Antarctic Fishes: A Comparative Approach to Environmental Stress

自4000-2500万年前南极大陆冰川出现、南美洲与南极半岛之间的德雷克海峡开通、南大洋开始降温以来，南极海洋生物的演化一直受到极端寒冷温度发展的驱动。在此期间，随着环南极海岸温度从~20°C下降到现代的-1.9°C到2.0°C(大约800万年前)，南大洋的嗜冷(爱冷)外温带进化出补偿性的分子、细胞和生理特征，使它们能够在低温下保持正常的新陈代谢功能。今天，这些生物受到南大洋几个世纪以来(高达5°C/100年)快速变暖的威胁，这一时间框架如此之短，以至于重新适应和/或适应新的变暖？可能是不可能的。因此，这一研究项目的长期目标是：1)了解南极诺氏鱼类胚胎抵抗或补偿海洋快速变暖的生化和生理能力；2)评估可用于支持南极诺氏鱼类胚胎适应和适应其变暖栖息地的遗传工具包。这项工作的具体目的是：1)确定在4-20℃温度范围内，诺氏鱼类伴侣蛋白复合体协助蛋白质折叠的能力；以及2)评估以1.9°C为正常温度的诺氏类胚胎对温度挑战的遗传反应(以全球差异基因转录衡量)。未来气候变化情景下海洋恒温动物胚胎发育的生理学是一个重要但未得到充分研究的问题。该项目将通过检查从生化到生物的多个层次的生物组织，对南极鱼类胚胎适应和适应似乎合理的气候变化情景的能力提供有价值的见解。这些结果也应该广泛适用于理解全球变暖对世界各地海洋生物群的影响。这项研究还将向研究生和REU本科生介绍与南极海洋生态系统的生态和环境问题有关的最先进的生化、细胞和分子生物学研究。

Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~40-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. As circum-Antarctic coastal temperatures declined during this period from ~20°C to the modern ?1.9 to +2.0°C (reached ~8-10 million years ago), the psychrophilic (cold-loving) ectotherms of the Southern Ocean evolved compensatory molecular, cellular, and physiological traits that enabled them to maintain normal metabolic function at cold temperatures. Today, these organisms are threatened by rapid warming of the Southern Ocean over periods measured in centuries (as much as 5°C/100 yr), a timeframe so short that re-adaptation and/or acclimatization to the ?new warm? may not be possible. Thus, the long-term goals of this research project are: 1) to understand the biochemical and physiological capacities of the embryos of Antarctic notothenioid fish to resist or compensate for rapid oceanic warming; and 2) to assess the genetic toolkit available to support the acclimatization and adaptation of Antarctic notothenioid embryos to their warming habitat. The specific aims of this work are: 1) to determine the capacity of the chaperonin complex of notothenioid fishes to assist protein folding at temperatures between ?4 and +20°C; and 2) to evaluate the genetic responses of notothenioid embryos, measured as global differential gene transcription, to temperature challenge, with ?1.9°C as the ?normal? control and +4 and +10°C as high temperature insults.The physiology of embryonic development of marine stenotherms under future climate change scenarios is an important but understudied problem. This project will provide valuable insights into the capacity of Antarctic fish embryos to acclimatize and adapt to plausible climate change scenarios by examining multiple levels of biological organization, from the biochemical to the organismal. The results should also be broadly applicable to understanding the impact of global warming on marine biota worldwide. The research will also introduce graduate and REU undergraduate students to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem.