Division of Life Science, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
Dev Dyn. 2011 Nov;240(11):2432-9. doi: 10.1002/dvdy.22751. Epub 2011 Oct 3.
Peronella japonica is a sand dollar with a zygote that develops into an abbreviated pluteus but then metamorphoses on day three. The adult rudiment formation is unique; it uses a median position of the hydrocoel and a stomodeum-like invagination of vestibule that covers the dorsal side of the hydrocoel. However, the developmental processes underlying coelom formation remain unclear. In this study, we examined this process by reconstructing three-dimensional images from serial sections of larvae. We show that the left coelom developed by both schizocoely and enterocoely from the archenteron tip, whereas the hydrocoel and right coelom formed by enterocoely from the archenteron. This coelom formation arranged the coelomic compartments directly along the adult oral-aboral axis by skipping the initial bilateral phases. Furthermore, our data indicate P. japonica retains ancestral asymmetry along the left-right axis in the location of the adult rudiment.
日本砂海星是一种具有受精卵的海胆，其胚胎发育成缩短的幼海胆，然后在第三天变态。成体原基的形成是独特的；它利用水腔的中位置和前庭的类似口道的内陷来覆盖水腔的背侧。然而，体腔形成的发育过程尚不清楚。在这项研究中，我们通过对幼虫的连续切片重建三维图像来检查这个过程。我们表明，左体腔通过原肠顶端的裂体腔和肠腔形成，而水腔和右体腔则通过原肠的肠腔形成。这种体腔形成通过跳过初始的双侧阶段，直接沿着成体的口-肛轴排列体腔隔室。此外，我们的数据表明，日本砂海星在成体原基的位置上保留了沿左右轴的祖先不对称性。
