The mechanisms of mitosis in higher eukaryotic organisms are very well studied; however, regarding protozoa, there are still many questions in need of an answer. Because of the complexity with which it carries out this process, many forms of mitosis exist, such as open orthomitosis, semi-open orthomitosis, semi-open pleuromitosis, closed intranuclear pleuromitosis, closed intranuclear orthomitosis, and closed extranuclear pleuromitosis. The fascinating aspect about the mitosis of Entamoeba histolytica trophozoites is that it falls out of the context of this classification, but not entirely. The Entamoeba histolytica trophozoites first carry out karyokinesis and then cytokinesis. The mitosis of this parasite is comprised of the following phases: prophase, metaphase, early and late anaphase, early and late telophase, and karyokinesis. The difference lies in the mechanism by which it carries out the distribution of the genetic material because it forms three mitotic spindles: two radial spindles that practically surround every group of chromosomes and one that we call inter microtubule-organizing centers (IMTOCs). The latter transports each group of chromosomes at each of the nucleus poles. Based on these observations, we propose that Entamoeba histolytica trophozoites carry out a type of mitosis we have called modified intranuclear pleuromitosis open.
Part of the book: Parasitology and Microbiology Research