Her鱼的特征是与海洋无脊椎动物相似的Om和iono符合性质。传统上,河豚被认为是保留多形性特征的最原始的活脊椎动物。然而,斑鱼的一些“祖先”特征,比如基本的眼睛和缺少椎骨,已经被证明是欺骗性的。同样,根据最大简约的原则,斑鱼独特的体液调节策略似乎是异形的,自从七翅目,另一个环管,采用渗透和离子调节机制,如颌骨脊椎动物。尽管在讨论脊椎动物渗透调节系统的起源和进化时,河豚无疑是重要的,对斑鱼体液稳态的分子基础了解甚少。在本研究中,我们在近岸盲鱼中探索了这个问题,BurgeriEptatretus,通过分析从ill获得的转录组,动物的肾脏和肌肉适应不同的环境盐度。连同肌液隔室参数的测量,我们的数据表明,盲鱼具有在细胞水平上进行基于游离氨基酸(FAA)的渗透调节的能力,这与肾脏和支气管FAA的吸收相协调。我们还发现,盲鱼确实具有已知的渗透调节基因的直系同源物,而且,无机离子在海鱼g和肾脏中的跨上皮运动比以前认为的要复杂得多。这些观察结果对传统观点提出了挑战,即马虎鱼的生理特征是从现存脊椎动物的最后一个共同祖先继承而来的。
Hagfishes are characterized by omo- and iono-conforming nature similar to marine invertebrates. Conventionally, hagfishes had been recognized as the most primitive living vertebrate that retains plesiomorphic features. However, some of the \"ancestral\" features of
hagfishes, such as rudimentary eyes and the lack of vertebrae, have been proven to be deceptive. Similarly, by the principle of maximum parsimony, the unique body fluid regulatory strategy of
hagfishes seems to be apomorphic, since the lamprey, another cyclostome, adopts osmo- and iono-regulatory mechanisms as in jawed vertebrates. Although
hagfishes are unequivocally important in discussing the origin and evolution of the vertebrate osmoregulatory system, the molecular basis for the body fluid homeostasis in
hagfishes has been poorly understood. In the present study, we explored this matter in the inshore hagfish, Eptatretus burgeri, by analyzing the transcriptomes obtained from the gill, kidney, and muscle of the animals acclimated to distinct environmental salinities. Together with the measurement of parameters in the muscular fluid compartment, our data indicate that the hagfish possesses an ability to conduct free amino acid (FAA)-based osmoregulation at a cellular level, which is in coordination with the renal and branchial FAA absorption. We also revealed that the hagfish does possess the orthologs of the known osmoregulatory genes and that the transepithelial movement of inorganic ions in the hagfish gill and kidney is more complex than previously thought. These observations pose a challenge to the conventional view that the physiological features of hagfishes have been inherited from the last common ancestor of the extant vertebrates.