Fertilization in Paramecium: Processes of the Nuclear Reorganization

Abstract

Publisher Summary This chapter focuses on the processes of nuclear reorganization, especially of germinal micronucleus, during and after conjugation in Paramecium . The process of fertilization in Paramecium is usually called “conjugation.” Nuclear phenomena during the sexual phase of ciliates including Paramecium are reviewed at the structural and ultrastructural levels, and at the molecular level. Because conjugation of Paramecium is induced simply by mixing cells of complementary-mating types and the sequence of nuclear changes proceeds almost synchronously in induced-conjugating pairs, it provides a reproducible and easily manipulatable system for the study of nuclear behavior. In conjugation of Paramecium , the processes of nuclear changes are grouped into three categories: (1) migration of the nucleus from one place to the other, (2) disintegration of some nuclei and survival of others, and (3) degradation of DNA in some nuclei and synthesis in others. Many advances in the study of nuclear changes during conjugation of Paramecium , especially using the nuclear-transplantation technique, lead to the discovery of much interesting new evidence.