标题： Kupffer氏囊中的三维流动 显示英文标题

标题： Three-dimensional flow in Kupffer's Vesicle

摘要： 尽管许多脊椎动物在外部看起来左右对称，但内部器官的排列是不对称的。 在斑马鱼中，左右对称性的打破是由库弗氏囊（KV）组织的：一个大约呈球形、充满液体的结构，在受精后10小时开始形成。 斑马鱼对称性打破的一个关键组成部分是在KV内建立纤毛驱动的流体流动。 然而，仍有不清楚的地方：（a）背侧、腹侧和赤道纤毛如何共同作用产生全局涡旋流动，以及（b）这种流动是否通过机械转导或形态发生素运输来打破左右对称性。 要完全回答这些问题需要了解KV内的三维流动模式，而这些模式在以前的工作中尚未被量化。 在本研究中，我们计算并分析了KV内的三维流动。 我们考虑了单个纤毛和纤毛群的流动，并（a）发现仅凭背侧顶盖上纤毛多于腹侧底面即可产生逆时针流动，展示了这种涡旋流动如何通过赤道纤毛的背侧倾斜而稳定，以及（b）表明背侧纤毛的前部聚集会导致前部比后部角落的流动速度快约40%。 我们认为这些流动特征支持通过机械感觉纤毛进行对称性打破，并提出了一种新的实验来验证这一假设。 基于我们对流动的新理解，我们提出进一步的实验来逆转KV内的流动，以可能诱导内脏反位。 显示英文摘要

摘要： Whilst many vertebrates appear externally left-right symmetric, the arrangement of internal organs is asymmetric. In zebrafish, the breaking of left-right symmetry is organised by Kupffer's Vesicle (KV): an approximately spherical, fluid-filled structure that begins to form in the embryo 10 hours post fertilisation. A crucial component of zebrafish symmetry breaking is the establishment of a cilia-driven fluid flow within KV. However, it is still unclear (a) how dorsal, ventral and equatorial cilia contribute to the global vortical flow, and (b) if this flow breaks left-right symmetry through mechanical transduction or morphogen transport. Fully answering these questions requires knowledge of the three-dimensional flow patterns within KV, which have not been quantified in previous work. In this study, we calculate and analyse the three-dimensional flow in KV. We consider flow from both individual and groups of cilia, and (a) find anticlockwise flow can arise purely from excess of cilia on the dorsal roof over the ventral floor, showing how this vortical flow is stabilised by dorsal tilt of equatorial cilia, and (b) show that anterior clustering of dorsal cilia leads to around 40% faster flow in the anterior over the posterior corner. We argue that these flow features are supportive of symmetry breaking through mechano-sensory cilia, and suggest a novel experiment to test this hypothesis. From our new understanding of the flow, we propose a further experiment to reverse the flow within KV to potentially induce situs inversus.