The viability of the anucleate cytoplasm of Amoeba proteus

The viability of Amoeba proteus cytoplasm was tested at 1-to 2-day intervals throughout the 14 days following enucleation. Viability was demonstrated by renucleating the anucleate cytoplasms and observing whether the resultant amoebae could resume normal activities such as moving, feeding and dividing. Four lines of A. proteus were studied, approximately 200 transfers being made on amoebae of each line. The introduction of a nucleus into anucleate cytoplasm initiated a temporary reactivation followed by a period of relative inactivity before either death by cytolysis or permanent reactivation with feeding, growth and division. Though approximately 70 % of anucleate cytoplasms were still viable 6 days after enucleation, temporary reactivation disappeared about this time and the period of relative inactivity which generally followed it increased in duration from a few days to several weeks. Few amoebae which were able to divide failed to form clones. Anucleate cytoplasms of wheat-cultured amoebae remained viable for longer periods than anucleate cytoplasms of tetrahymena-fed amoebae.