将沙粒中的原肠胚形成过程与海胆半entrotuspulcherrimus中的原肠胚形成过程进行了比较,这似乎显示了典型的原肠胚形成模式。对弓形虫长度的测量清楚地表明,H.pulcherrimus的内陷过程分为两个阶段,原发性和继发性内陷。另一方面,在S.mirabilis中内陷被发现以恒定的速度继续。为了观察原肠胚形成过程中细胞的运动,胚胎用尼罗蓝标记。在H.pulcherrimus胚胎中,标记的细胞沿着肠子的全长观察,如果胚胎在初次内陷之前和期间被标记过。在初次内陷后染色的胚胎中从未观察到标记的细胞。相比之下,标记的细胞总是在S.mirabilis的初级肠的基底部分被识别出来,即使胚胎内陷后染色也有了相当大的进步。S.mirabilis胚胎初肠细胞的数量随着胃泌素的增加而增加,而H.pulcherrimus的数量几乎恒定。这些结果表明,奇异链球菌中胃泌素的细胞基础与众所周知的海胆物种中的细胞基础完全不同。
Processes of
gastrulation in the sand dollar Scaphechinus mirabilis were compared with those in the sea urchin Hemicentrotus pulcherrimus, which seemed to show a typical pattern of
gastrulation. Measurement of the archenteron length clearly demonstrated that invagination processes in H. pulcherrimus are divided into two phases, the primary and secondary invagination. On the other hand, invagination in S. mirabilis was revealed to continue at a constant rate. To see the movement of cells during
gastrulation, embryos were labeled with Nile blue. In H. pulcherrimus embryos, labeled cells were observed along the full length of the archenteron, if the embryos had been labeled before and during the primary invagination. Labeled cells were never observed in the embryos stained after the primary invagination. In contrast, labeled cells were always discerned at the basal part of the archenteron in S. mirabilis, even if the embryos were stained after invagination had undergone considerable progress. The number of cells in the archenteron of S. mirabilis embryos increased with the advancement of
gastrulation, while the numbers were almost constant in H. pulcherrimus. These results suggest that the cellular basis of
gastrulation in S. mirabilis is quite different from that in well-known species of sea urchins.