小柯机器人

加拿大英属哥伦比亚大学Michael A. Sackville等研究人员发现，鳃的离子调节先于气体交换和脊椎动物的起源。相关论文于2022年10月19日在线发表在《自然》杂志上。

研究人员描述了一种脊椎动物（沙隐虫；Entosphenus tridentatus）、一种头索动物（文昌鱼；Branchiostoma floridae）和一种半索动物（橡实虫；Saccoglossus kowalevskii）的鳃和皮肤的功能，这些动物具有脊椎动物祖先假定的钻入和滤食特征。研究人员为脊椎动物的气体交换起源于鳃提供了功能上的支持，因为体内的直接测量显示，鳃是气体交换的主要部位，只有在沙隐虫中，而且只有在身体尺寸增加或氧气供求的挑战下才是如此。

相反，所有三个分类群的鳃都与离子调节有关。沙隐虫的鳃负责所有体型的所有离子通量，而文昌鱼和橡实虫的鳃中离子调节的分子标记比皮肤中的高。这表明，腮部的离子调节比气体交换的起源更早，与脊椎动物的大小和活动无关，也许是在后口动物的咽孔开始时。

据介绍，鳃的气体交换和离子调节在脊椎动物的进化中具有关键作用。据推测，鳃首先从脊椎动物的皮肤获得了这些重要的平衡功能，促进了更大、更活跃的生命模式演化。然而，这一假设在相关分类群中缺乏功能支持。

附：英文原文

Title: Ion regulation at gills precedes gas exchange and the origin of vertebrates

Author: Sackville, Michael A., Cameron, Christopher B., Gillis, J. Andrew, Brauner, Colin J.

Issue&Volume: 2022-10-19

Abstract: Gas exchange and ion regulation at gills have key roles in the evolution of vertebrates1,2,3,4. Gills are hypothesized to have first acquired these important homeostatic functions from the skin in stem vertebrates, facilitating the evolution of larger, more-active modes of life2,3,5. However, this hypothesis lacks functional support in relevant taxa. Here we characterize the function of gills and skin in a vertebrate (lamprey ammocoete; Entosphenus tridentatus), a cephalochordate (amphioxus; Branchiostoma floridae) and a hemichordate (acorn worm; Saccoglossus kowalevskii) with the presumed burrowing, filter-feeding traits of vertebrate ancestors6,7,8,9. We provide functional support for a vertebrate origin of gas exchange at the gills with increasing body size and activity, as direct measurements in vivo reveal that gills are the dominant site of gas exchange only in ammocoetes, and only with increasing body size or challenges to oxygen supply and demand. Conversely, gills of all three taxa are implicated in ion regulation. Ammocoete gills are responsible for all ion flux at all body sizes, whereas molecular markers for ion regulation are higher in the gills than in the skin of amphioxus and acorn worms. This suggests that ion regulation at gills has an earlier origin than gas exchange that is unrelated to vertebrate size and activity—perhaps at the very inception of pharyngeal pores in stem deuterostomes.

DOI: 10.1038/s41586-022-05331-7

Source: https://www.nature.com/articles/s41586-022-05331-7

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
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