Ultrastructural studies on mitosis in Trypanosoma danilewskyi (Mastigophora: Zoomastigophorea)

Abstract

1984. Ultrastructural studies on mitosis in Tppcinosoma danilewskyi (Mastigophora: Zoomastigophorea). Can. J. Zool. 62: 1 167-1 17 1 .Mitosis of Trypanosoma danilewskyi was studied using transmission electron microscopy. The basal body replicates prior to the kinetoplast. Nuclear division is coincident with the first part of cytokinesis. The kinetoplast DNA appears to disaggregate and then recondense as two strands. In the early phase of mitosis the chromatin and nucleolar material also disaggregate, but the nuclear membranes persist throughout mitosis. Electron-dense plaques, possibly kinetochores, were observed on the spindle rnicrotubules in the polar regions of dividing nuclei. Additional electron-dense material was observed on the inner nuclear membranes adjacent to the plaques and rnicrotubules but without connection to these latter structures. Daughter nuclei migrate but remain temporarily connected by a bridge composed of spindle microtubules enclosed by both nuclear membranes. During the final stages of karyokinesis the inner nuclear membrane reorganizes to exclude the rnicrotubules of the bridge from the nucleoplasm. The nucleolus and chromatin reform, with the nucleolus being temporarily connected to the inner nuclear membrane by a chromatin strand. Cytokinesis is accomplished by transverse symmetrogenic fission, and the daughter cells are temporarily connected by a cytoplasmic isthmus. PATERSON, W. B., et P. T . K. Woo. 1984. Ultrastructural studies on mitosis in Tppanosoma danilewskyi (Mastigophora: Zoomastigophorea) . Can. J . Zool . 62: 1 167 -1 17 1 .Nous avons CtudiC la mitose de Trypanosoma danilewlskyi au moyen d'un microscope Clectronique a transmission. Le corpuscule de base se dCdouble avant le cinCtoplaste. La division du noyau coi'ncide avec la premiere phase de la cytocinese. L'ADN du cinCtoplaste semble se dCsagrCger, puis se reformer en deux bandes. Dans la premiere phase de la mitose, la chromatine et les composantes du nuclCole se dksagrkgent Cgalement. Les membranes nuclCaires demeurent intactes pendant toute la mitose. Des plaques opaques au microscope Clectronique, peut-Ctre des cinCtochores, ont Ct C observCes sur les microtubules du fuseau dans les rigions polaires des noyaux en division. D'autres ClCments, opaques Cgalement, ont CtC observks sur les membranes nuclCaires internes adjacentes aux plaques et aux rnicrotubules, mais ils ne sont pas relies a ces structures. Les noyaux filles migrent, mais demeurent temporairement reliCs par un pont constituC de microtubules du fuseau enclaves dans les deux membranes nuclkaires. Au cours des dernieres phases de la caryocinkse, la membrane nuclCaire interne se rkorganise de maniere ii expulser du nuclCoplasme les microtubules du pont. Le nuclCole et la chromatine se reforment et le nuclCole demeure temporairement relie par une bande de chromatine a la membrane nuclCaire interne. La cytocinese se fait par scission symktrogene transversale. Les cellules filles demeurent temporairement relikes par un isthme cytoplasmique.[Traduit par le jo...

First record of Trypanosoma sp. (Protozoa: Kinetoplastida) in tuvira (Gymnotus aff. inaequilabiatus) in the Pantanal wetland, Mato Grosso do Sul State, Brazil

“…Multiplication of these hemofl agellates in blood tissue has been described in some vertebrate hosts (PATERSON; WOO, 1984;BURRESON;KARLSBAKK, 2007). Th is division may be an adaptive mechanism, if the pathogenicity of these trypanosomes for their hosts is dependent on the intensity of the parasitemia (BURRESON; KARLSBAKK, 2007).…”

Ultrastructure of culture forms of the eel trypanosome, Trypanosoma granulosum Laveran & Mesnil, 1902, exposed to polyamine biosynthesis inhibitors

“…These control organisms showed subpellicular microtubules, a flagellum and paraxial rod, kinetoplast and mitochondrial complex, nucleus, and general cytoplasmic organelles which were generally unremarkable. Although duplicate flagella, kinetoplasts and nuclei were seen in several cultured T. granulosum, the fine details of mitosis which have been recorded in cultured fish flagellates such as Trypanosoma raiae, Trypanosoma dunilewskyi and Trypanoplasma borreli (Vickerman & Preston 1970;Paterson & Woo 1984;Skarlato & Lom 1997) were not observed. A cytopharynx was not identified clearly in cultured T. granulosum, but the long, fibrous structures, which were also prominent in cells treated with 0.2 mM MGBG, were similar to the cytopharynx-associated microtubules recorded from the epimastigotes of the fish trypanosome Trypanosoma cobitis in the crop of its leech vector and from culture ( h i s & Ball 1980& Ball , 1981.…”

In Vitro Cellular Division of Trypanosoma abeli Reveals Two Pathways for Organelle Replication

“…For freshwater and marine fish trypanosomes, the sequence of cellular organelle segregation, during the binary fission process, has been studied ex vivo and in vitro. Similar to T. brucei and T. cruzi, some species of freshwater fish trypanosomes exhibit kinetoplast division prior to the nucleus, during vertebrate or invertebrate host infection, as well as during in vitro culture (Jones and Woo 1991a;Paterson and Woo 1984;Woo 1981Woo , 2006. However, this study provides new information regarding the division process of these protozoa from the analysis of Trypanosoma abeli cultured in vitro.…”

“…brucei and T . cruzi , some species of freshwater fish trypanosomes exhibit kinetoplast division prior to the nucleus, during vertebrate or invertebrate host infection, as well as during in vitro culture (Jones and Woo ; Paterson and Woo ; Woo , ). However, this study provides new information regarding the division process of these protozoa from the analysis of Trypanosoma abeli cultured in vitro.…”