Laboratório de Ecofisiologia e Evolução Molecular, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.
Genet Mol Biol. 2011 Apr;34(2):315-22. doi: 10.1590/s1415-47572011000200025. Epub 2011 Apr 1.
Adaptation or acclimation to hypoxia occurs via the modulation of physiologically relevant genes, such as erythropoietin, transferrin, vascular endothelial growth factor, phosphofructokinase and lactate dehydrogenase A. In the present study, we have cloned, sequenced and examined the modulation of the LDH-A gene after an Amazonian fish species, Astronotus crassipinis (the Oscar), was exposed to hypoxia and anoxia. In earlier studies, we have discovered that adults of this species are extremely tolerant to hypoxia and anoxia, while the juveniles are less tolerant. Exposure of juveniles to acute hypoxia and anoxia resulted in increased LDH-A gene expression in skeletal and cardiac muscles. When exposed to graded hypoxia juveniles show decreased LDH-A expression. In adults, the levels of LDH-A mRNA did not increase in hypoxic or anoxic conditions. Our results demonstrate that, when given time for acclimation, fish at different life-stages are able to respond differently to survive hypoxic episodes.
适应或驯化低氧环境是通过调节与生理相关的基因来实现的，如促红细胞生成素、转铁蛋白、血管内皮生长因子、磷酸果糖激酶和乳酸脱氢酶 A。在本研究中，我们克隆、测序并研究了亚马逊鱼类——Astronotus crassipinis（奥斯卡鱼）在暴露于低氧和缺氧环境后，LDH-A 基因的调节情况。在早期的研究中，我们发现该物种的成鱼对低氧和缺氧环境具有极强的耐受性，而幼鱼的耐受性则较低。将幼鱼暴露于急性低氧和缺氧环境中会导致其在骨骼和心肌中的 LDH-A 基因表达增加。当幼鱼暴露于逐渐降低的氧环境中时，LDH-A 表达会减少。而成鱼在低氧或缺氧条件下，LDH-A mRNA 水平并没有增加。我们的结果表明，在给予适应时间的情况下，处于不同生命阶段的鱼类能够以不同的方式对低氧环境做出反应，以生存下来。
