Asexual reproduction in Trichoplax occurs mainly by binary fission and occasionally by the budding of epithelial spheres called "swarmers". The process that leads to binary fission and the mechanisms involved in this segregation are practically unknown. Trichoplax lacks a defined shape, presenting a constantly changing outline due to its continuous movements and body contractions. For this reason, and due to the absence of anatomical references, it has been classified as an asymmetric organism. Here, we report that a transient wound is formed in the marginal epithelium of the two new individuals produced by binary fission. By tracking the location of this epithelial wound, we can determine that successive dichotomous divisions are orthogonal to the previous division. We also found that LiCl paralyzes the cilia beating movement and body contractions and causes the placozoans to become circular in shape. This effect, as well as a stereotypic body folding behavior observed in detached placozoans and cell labeling experiments of the upper epithelium, indicate a cylindrical body symmetry for Placozoa.

中文翻译：

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Trichoplax 中的二元裂变与随后的分割平面正交

Trichoplax 的无性繁殖主要通过二元裂变发生，偶尔通过被称为“蜂群”的上皮球的萌芽发生。导致二元裂变的过程和这种分离所涉及的机制实际上是未知的。Trichoplax 缺乏明确的形状，由于其连续运动和身体收缩，呈现出不断变化的轮廓。出于这个原因，并且由于缺乏解剖学参考，它被归类为不对称生物。在这里，我们报告在二元裂变产生的两个新个体的边缘上皮中形成了短暂的伤口。通过跟踪这个上皮伤口的位置，我们可以确定连续的二分法与之前的分法是正交的。我们还发现氯化锂使纤毛跳动和身体收缩麻痹，并使平台动物变成圆形。这种效应，以及在分离的平台动物和上皮细胞标记实验中观察到的刻板身体折叠行为，表明平台动物的圆柱体对称性。