Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Hatching in Ascidia ceratodes and evidence for a hatching enzyme
Student Author(s): Lim, Damon
Pages: 23
Location: Final Papers Biology 175H
Date: June 1981
Keywords: ascidians
Abstract: Hatching in Ascidia ceratodes seemingly involves two inter-related functions - that of movement to cause rupture, and enzymatic removal of the follicle cells and possibly, enzymatic digestion of the chorion to facillitate escape. Direct evidence of the importance of movement was not obtained, however indirect evidence as seen in increased movement prior to hatching; decreased hatching time in defolliculated eggs, and non-specific sites of rupture, all tend ot suggest its importance. Direct evidence of a hatching enzyme was obtained using an unconventional and novel assaying agent - Stronglyocentrotus purpuratus eggs. Trypsin-like enzymes cause defolliculation and are essential in the overall hatching process. Inhibition of the enzymatic activity prevents hatching.