THE EFFECTS OF SELECTED CHEMICAL AGENTS ON FURROW INDUCTION IN THE EGGS OF ARBACIA PUNCTULATA

¹ Department of Zoology, University of Toronto, Toronto, Canada, and Marine Biological Laboratory, Woods Hole, Massachusetts

Following high speed pressure-centrifugation treatment, fertilized eggs of Arbacia punctulata exhibit a furrowing reaction prior to cytokinesis. Fertilized eggs were incubated in metabolic and mitotic inhibitors and the effects of these agents on frequency, stability and position of the induced furrows were observed. Puromycin and p-fluorophenylalanine (inhibitors of protein synthesis), in concentrations which inhibit cytokinesis in control cells, did not prevent the induced furrowing reaction, although the frequency of furrow induction was reduced. Actinomycin D (an inhibitor of mRNA synthesis) had no effect on furrow induction. Heavy water and colcemid, at concentrations which block pronuclear fusion and cell division, did not block furrow induction. Mercaptoethanol treatment (at concentrations which block cytokinesis) did not reduce the frequency of induced furrows but resulted in less stable furrows and in shifting of the plane of furrow to an equatorial position. Agents that block oxidative phosphorylation (cornin, dinitro-o-cresol, dinitrophenol) did not block the furrowing reaction, although first division was markedly delayed. The results are discussed in terms of the effects of mitotic and cytokinetic inhibitors on experimental furrow induction.