CYCLIC SURFACE CHANGES IN THE NON‐NUCLEATE EGG FRAGMENT OF XENOPUS LAEVIS

Abstract

Fertilized uncleaved eggs of Xenopus laevis were divided into nucleate and non‐nucleate egg fragments. Both fragments, together with the whole egg of the same batch, were observed by time‐lapse cinematography. Two kinds of cyclic surface changes, (1) rounding‐up and relaxing movements and (2) surface contraction waves, accompanying each cleavage in the whole eggs and the nucleate fragments, were also observed even in the non‐nucleate fragments although they do not cleave. Cleavage intervals of the whole egg and the nucleate fragment were nearly equal, but the rounding‐up intervals of the non‐nucleate fragment were slightly but definitely longer than the cleavage intervals of the nucleate fragment and the whole egg. Copyright © 1981, Wiley Blackwell. All rights reserved