Development of swimming behavior in sea urchin embryos. II

✍ Scribed by Maruyama, Y. K.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 627 KB
• Volume: 217
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402170211

✦ Synopsis

Abstract

The previous study has revealed that sea urchin prehatching embryos exhibited either clockwise or counterclockwise spin on the animal—vegetal axis, whereas the hatched embryos showed only counterclockwise spin. This behavioral change at hatching was analyzed in the present study by testing the “mechanical interaction hypothesis” proposed in the previous paper. Observations of the spinning behavior have been made of (1) embryos without the fertilization membrane (denudation experiment), (2) those embedded in fibrin gel at the prehatching or free‐swimming stages (maintenance or induction experiments), and (3) those liberated into seawater after the embedding (liberation experiment). The results have provided evidence to support the hypothesis that the duality of the spinning behavior in the prehatching embryos is due to a mechanical or hydrodynamic interaction between the cilia and the inner surface of the fertilization membrane, independent of the developmental stage of the embryo proper. Thus it is concluded that the change in the spinning behavior of embryos after hatching is brought about solely by their release from the fertilization membrane.