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

9421657 Sidell在过去的大约4000万年里，一种独特的鱼类动物群一直在南极洲周围的寒冷海洋中进化。 这些水呼吸动物的生理功能需要许多适应，以确保在细胞温度约为0 ℃时适当的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，那就是南极冰鱼科。 这个家族中的物种在循环血液中缺乏血红蛋白，并且至少大多数不具有细胞内呼吸蛋白肌红蛋白，肌红蛋白通常负责通过有氧肌肉组织增强氧气的运动。 然而，PI最近发现了两种冰鱼，Pseudochaenichthys georgianus和Chionodraco rastrospinosus，表达肌红蛋白，但仅在一种组织中-心室。 所有冰鱼物种的新陈代谢都是高度有氧的，主要基于脂肪燃料的燃烧作为能源。 实地工作将包括R/V Polar杜克号拖网捕捞冰鱼物种和帕尔默站使用这些动物组织的实验室工作。 在帕尔默站，他们将进行实验，并准备纯化，固定和/或冷冻材料运回我们的CONUS实验室进行进一步分析。 我们的总体目标是：1）测试是否确定肌红蛋白在南极鱼的寒冷体温下仍然具有生理学意义，2）重建肌红蛋白基因在冰鱼家族内的进化，3）鉴定控制肌红蛋白在冰鱼和相关物种内表达的机制。

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.