Lindsey Benjamin W, Dumbarton Tristan C, Moorman Stephen J, Smith Frank M, Croll Roger P
Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada.
J Exp Zool A Ecol Genet Physiol. 2011 Jun 1;315(5):302-13. doi: 10.1002/jez.677. Epub 2011 Mar 10.
The gas-filled swimbladder of teleost fishes provides hydrodynamic lift which counteracts the high density of other body tissues, and thereby allows the fish to achieve neutral buoyancy with minimal energy expenditure. In this study, we examined whether the absence of a constant direction gravitational vector affects the ontogeny of the swimbladder and buoyancy control in zebrafish (Danio rerio). We exposed fertilized eggs to simulated microgravity (SMG) in a closed rotating wall vessel with control eggs placed in a similar but nonrotating container. All eggs hatched in both groups. At 96 hr of postfertilization (hpf), all larvae were removed from the experimental and control vessels. At this point, 62% of the control larvae, but only 14% of SMG-exposed larvae, were observed to have inflated their swimbladder. In addition, the mean volume of the inflated swimbladders was significantly greater in the control larvae compared with larvae raised in SMG. After transfer to open stationary observation tanks, larvae with uninflated swimbladders in both groups swam to the surface to complete inflation, but this process was significantly delayed in larvae exposed to SMG. Initial differences in swimbladder inflation and volume between groups disappeared by 144 hpf. Furthermore, there were no apparent changes in patterns of development and maturation of swimbladder musculature, vasculature, or innervation resulting from SMG exposure at later stages of ontogeny. These data indicate that, despite a transient delay in swimbladder inflation in zebrafish larvae exposed to SMG, subsequent swimbladder development in these animals proceeded similarly to that in normal larvae.
硬骨鱼类充满气体的鱼鳔提供水动力升力，抵消了身体其他组织的高密度，从而使鱼能够以最小的能量消耗实现中性浮力。在本研究中，我们研究了缺乏恒定方向的重力矢量是否会影响斑马鱼（Danio rerio）鱼鳔的个体发育和浮力控制。我们将受精卵置于封闭的旋转壁容器中以模拟微重力（SMG），并将对照卵置于类似但不旋转的容器中。两组的所有卵均孵化。在受精后96小时（hpf），将所有幼虫从实验和对照容器中取出。此时，观察到62%的对照幼虫鱼鳔已充气，但暴露于SMG的幼虫中只有14%鱼鳔充气。此外，与在SMG中饲养的幼虫相比，对照幼虫中充气鱼鳔的平均体积明显更大。转移到开放的固定观察水箱后，两组中鱼鳔未充气的幼虫都游向水面以完成充气，但暴露于SMG的幼虫这一过程明显延迟。到144 hpf时，两组之间鱼鳔充气和体积的初始差异消失。此外，在个体发育后期，暴露于SMG并未导致鱼鳔肌肉组织、脉管系统或神经支配的发育和成熟模式出现明显变化。这些数据表明，尽管暴露于SMG的斑马鱼幼虫鱼鳔充气存在短暂延迟，但这些动物随后的鱼鳔发育与正常幼虫相似。
