Observations on division stages in the protozoan hypotrich Stylonychia

Abstract

The study of mitotic events by electron microscopy has been greatly retarded by inability to select dividing cells among the relatively much greater proportion of cells that are not in division. The protozoa, even though their micronuclear division represents a specialized type of mitosis, offer the possibility of isolation and observation of selected cytological events and therefore provide choice material for such observations. In addition, the ciliate protozoa exhibit special macronuclear morphology at the time of deoxyribose nucleic acid synthesis, a highly specialized division of the macronucleus and, further more, engage in the formation of a rather large number of cilia in a short time. Therefore, dividing ciliates offer the possibility for study of the four events, micronuclear mitosis, macronuclear nucleic acid synthesis, macronuclear division, and ciliary formation.

This work was performed under the auspices of the US Atomic Energy Commission.