Venuto Alexandra, Thibodeau-Beganny Stacey, Trapani Josef G, Erickson Timothy
Department of Biology, East Carolina University, Greenville, NC, USA.
Department of Biology and Neuroscience Program, Amherst College, Amherst, MA, USA.
bioRxiv. 2023 Apr 24:2023.01.12.523756. doi: 10.1101/2023.01.12.523756.
Larval zebrafish achieve neutral buoyancy by swimming up to the surface and taking in air through their mouths to inflate their swim bladders. We define this behavior as 'surfacing'. Little is known about the sensory basis for this underappreciated behavior of larval fish. A strong candidate is the mechanosensory lateral line, a hair cell-based sensory system that detects hydrodynamic information from sources like water currents, predators, prey, and surface waves. However, a role for the lateral line in mediating initial inflation of the swim bladder has not been reported. To explore the connection between the lateral line and surfacing, we utilized a genetic mutant ( ) that renders the zebrafish lateral line insensitive to mechanical stimuli. We observe that approximately half of these lateral line mutants over-inflate their swim bladders during initial inflation and become positively buoyant. Thus, we hypothesize that larval zebrafish use their lateral line to moderate interactions with the air-water interface during surfacing to regulate swim bladder inflation. To test the hypothesis that lateral line defects are responsible for swim bladder over-inflation, we show exogenous air is required for the hyperinflation phenotype and transgenic rescue of hair cell function restores normal inflation. We also find that chemical ablation of anterior lateral line hair cells in wild type larvae causes hyperinflation. Furthermore, we show that manipulation of lateral line sensory information results in abnormal inflation. Finally, we report spatial and temporal differences in the surfacing behavior between wild type and lateral line mutant larvae. In summary, we propose a novel sensory basis for achieving neutral buoyancy where larval zebrafish use their lateral line to sense the air-water interface and regulate initial swim bladder inflation.
斑马鱼幼体通过游到水面并通过嘴巴吸入空气来使鱼鳔充气，从而实现中性浮力。我们将这种行为定义为“浮出水面”。对于幼体鱼这种未得到充分认识的行为的感觉基础，人们了解甚少。一个有力的候选因素是机械感觉侧线，这是一种基于毛细胞的感觉系统，可检测来自水流、捕食者、猎物和表面波等来源的流体动力学信息。然而，尚未有报道表明侧线在介导鱼鳔的初始充气中发挥作用。为了探究侧线与浮出水面行为之间的联系，我们利用了一种基因变异体（ ），该变异体使斑马鱼侧线对机械刺激不敏感。我们观察到，这些侧线突变体中约有一半在初始充气过程中鱼鳔过度充气并变得具有正浮力。因此，我们推测斑马鱼幼体在浮出水面时利用其侧线来调节与气水界面的相互作用，以控制鱼鳔充气。为了验证侧线缺陷导致鱼鳔过度充气这一假设，我们表明过度充气表型需要外源空气，并且毛细胞功能的转基因拯救可恢复正常充气。我们还发现，对野生型幼体的前侧线毛细胞进行化学消融会导致过度充气。此外，我们表明对侧线感觉信息的操控会导致异常充气。最后，我们报告了野生型和侧线突变体幼体在浮出水面行为上的时空差异。总之，我们提出了一种实现中性浮力的新感觉基础，即斑马鱼幼体利用其侧线来感知气水界面并调节鱼鳔的初始充气。
