Journal of Cell Science, Vol 39, 201-213, Copyright © 1979 by Company of Biologists

Submitted on October 24, 1978
Revised on February 22, 1979

Specific Contact-Dependent Cell-Tocell Communication During Preconjugant Interaction of the Ciliate Euplotes Crassus

¹ Institute of Zoology, University of Camerino (MC), Via Camerini 2, Italy
² Institute of Zoology, University of Camerino (MC), Via Camerini 2, Italy; Institute of Zoology, University of Pisa, Italy
³ Institute of Zoology, University of Pisa Italy; Hospital of Pietrasanta (LU), Section Microbiology, Italy

A system has been developed to study cellular interactions between cells of complementary mating types prior to mating in the ciliate, Euplotes crassus. The presumptive mates were distinguished by using singlet and doublet cells of appropriate mating types in the mixtures. Cells of a given mating type were prelabelled with [³H]leucine and mixed with unlabelled complementary cells. Exchange of [³H]leucine-labelled material from donor to recipient cells was monitored through the various stages of the preconjugant interaction. A label transfer between the mating type complementary cells was detected from the beginning of the visible mating reaction, which occurs after a waiting period from the time of cell mixing and involves ciliary agglutination prior to cell body fusion. Complementary cells which were prevented from physically contacting each other and cells which were not competent to mate appeared unable to take up the labelled material. It is suggested that this material consists of some substance(s) playing an important role in the preconjugant cell-to-cell interactions of E. crassus.