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The mitotic spindle and associated membranes in the closed mitosis of trichomonads
Author(s) -
Ribeiro Karla Consort,
PereiraNeves Antonio,
Benchimol Marlene
Publication year - 2002
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/s0248-4900(02)01191-7
Subject(s) - biology , microtubule organizing center , microtubule , mitosis , astral microtubules , microbiology and biotechnology , spindle apparatus , spindle pole body , cytoplasm , nuclear membrane , nucleus , cell division , cell , cell cycle , centrosome , genetics
In the present work, we followed the several phases of Tritrichomonas foetus and Trichomonas vaginalis cell cycles using immunofluorescence, serial thin sections, three‐dimensional (3D) reconstruction, and transmission electron microscopy. In motile trichomonad cells or in pseudocyst forms, the nuclear envelope persists throughout mitosis, and the spindle is extranuclear. We found three types of spindle microtubules: pole‐to‐nucleus microtubules which are attached to the nuclear envelope, pole‐to‐pole microtubules forming a cylindrical, cytoplasmic groove on the nuclear compartment in pseudocysts of T. foetus cells, and pole‐to‐cytosol microtubules which extend freely into the cytoplasm. We demonstrated that: (1) in T. foetus , the spindle is assembled from an MTOC located at the base of the costa, underneath one of the basal bodies; (2) the spindle presents an unusual arc shape during the initial phases of mitosis in motile trophozoites; (3) the spindle microtubules are glutamylated, but not acetylated; (4) several membranes similar to those of the endoplasmic reticulum follow the spindle microtubules; (5) finger‐like projections extend from the nucleus towards the cell poles in pseudocysts and multinucleated cells; and (6) vesicles formed in between the two nuclear membranes are seen in the course of mitosis in both trophozoite and pseudocyst forms.