Physik-Institut, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
J Exp Biol. 2021 Aug 1;224(15). doi: 10.1242/jeb.242309. Epub 2021 Aug 2.
Understanding how extrinsic factors modulate genetically encoded information to produce a specific phenotype is of prime scientific interest. In particular, the feedback mechanism between abiotic forces and locomotory organs during morphogenesis to achieve efficient movement is a highly relevant example of such modulation. The study of this developmental process can provide unique insights on the transduction of cues at the interface between physics and biology. Here, we take advantage of the natural ability of adult zebrafish to regenerate their amputated fins to assess its morphogenic plasticity upon external modulations. Using a variety of surgical and chemical treatments, we could induce phenotypic responses to the structure of the fin. Through the ablation of specific rays in regenerating caudal fins, we generated artificially narrowed appendages in which the fin cleft depth and the positioning of rays bifurcations were perturbed compared with normal regenerates. To dissect the role of mechanotransduction in this process, we investigated the patterns of hydrodynamic forces acting on the surface of a zebrafish fin during regeneration by using particle tracking velocimetry on a range of biomimetic hydrofoils. This experimental approach enabled us to quantitatively compare hydrodynamic stress distributions over flapping fins of varying sizes and shapes. As a result, viscous shear stress acting on the distal margin of regenerating fins and the resulting internal tension are proposed as suitable signals for guiding the regulation of ray growth dynamics and branching pattern. Our findings suggest that mechanical forces are involved in the fine-tuning of the locomotory organ during fin morphogenesis.
了解外在因素如何调节遗传编码信息以产生特定表型是一个非常重要的科学研究课题。特别是，生物力学和运动器官在形态发生过程中反馈机制以实现高效运动，这是这种调节的一个非常相关的例子。研究这个发育过程可以为物理和生物学界面的信号转导提供独特的见解。在这里，我们利用成年斑马鱼自然再生其断鳍的能力，评估其在外部调节下的形态可塑性。通过各种手术和化学处理，我们可以诱导鳍的表型反应。通过切除再生尾鳍中的特定射线，我们生成了人为变窄的附肢，与正常再生的附肢相比，其鳍裂深度和射线分叉的位置受到干扰。为了剖析机械转导在这个过程中的作用，我们通过在一系列仿生水翼上使用粒子追踪速度测量法，研究了在再生过程中作用在斑马鱼鳍表面的水动力。这种实验方法使我们能够定量比较不同大小和形状的拍打鳍的流体力分布。结果表明，作用在再生鳍远端边缘的粘性剪切力和由此产生的内部张力被提出作为指导射线生长动力学和分支模式调节的合适信号。我们的研究结果表明，机械力在鳍形态发生过程中参与了运动器官的微调。
