Evolution of an Oxygen-Binding Hemoprotein in a Unique Environment: Myoglobin in the Hemoglobinless Antarctic Icefishes

9421657西德尔在过去的大约4000万年里，一个独特的鱼类动物群一直在南极洲周围寒冷的海洋中进化。这些水栖动物的生理功能需要许多适应，以确保在细胞温度约为OOC的情况下适当的新陈代谢和生化过程的调节。在极地鱼类中，有一个科特别不寻常，那就是金枪鱼。这个家族的物种在循环血液中缺乏血红蛋白，至少大多数物种不具有细胞内呼吸蛋白-肌红蛋白，肌红蛋白通常负责促进氧气在有氧肌肉组织中的运动。然而，Pi‘s最近发现了两种冰鱼，Partiochaenichthys georgianus和Chion odraco rastrospinosus，它们只在一个组织-心脏脑室表达肌红蛋白。所有种类的冰鱼的新陈代谢都是高度有氧的，主要基于作为能源的脂肪燃料的燃烧。实地工作将包括从R/V Polar Duke拖网捕获冰鱼物种，以及在Palmer站使用这些动物的组织进行实验室工作。在帕尔默空间站，他们将进行实验，准备纯化、固定和或冷冻的材料，然后运回我们的CONUS实验室进行进一步分析。我们的总体目标是：1)测试在南极鱼类寒冷的体温下，肌红蛋白蛋白是否仍然具有生理意义；2)重建冰鱼家族中肌红蛋白基因的进化；3)确定肌红蛋白在冰鱼及其近缘物种中表达的控制机制。

9421657 Sidell For approximately the last 40 million years, a unique fish fauna has been evolving in the frigid seas surrounding Antarctica. Physiological function of these water-breathing animals has demanded many adaptations to ensure proper metabolism and regulation of biochemical processes at cell temperatures of about OoC. Among the polar fishes, one family is particularly unusual, the Channichthyid icefishes. Species in this family lack hemoglobin in their circulating blood and, at least the majority, do not possess the intracellular respiratory protein, myoglobin, that is normally responsible for enhancing movement of oxygen through aerobic muscle tissues. The PI's have recently found two species of icefish, Pseudochaenichthys georgianus and Chionodraco rastrospinosus, however, that express myoglobin, but only in one tissue - heart ventricle. The metabolism of all icefish species is highly aerobic and is based largely on the combustion of fatty fuels as energy sources. The field work will consist of a combination of trawling from R/V Polar Duke to capture icefish species and laboratory work at Palmer Station using tissues from these animals. At Palmer Station they will conduct experiments and prepare purified, fixed and or frozen material for shipment back to our CONUS laboratory for further analyses. Our overall goals are: 1) to test whether to determine myoglobin protein remains physiologically significant at the cold body temperatures of Antarctic fishes, 2) to reconstruct the evolution of the myoglobin gene within the icefish family and, 3) to identify the mechanisms controlling expression of myoglobin within icefish and related species.