Summary
The three-dimensional ultrastructural organization of the mitotic apparatus ofDimastigella mimosa was studied by computer-aided, serial-section reconstruction. The nuclear envelope remains intact during nuclear division. During mitosis, chromosomes do not condense, whereas intranuclear microtubules are found in close association with six pairs of kinetochores. No discrete microtubule-organizing centers, except kinetochore pairs, could be found within the nucleus. The intranuclear microtubules form six separate bundles oriented at different angles to each other. Each bundle contains up to 8 tightly packed microtubules which push the daughter kinetochores apart. At late anaphase only, midzones of these bundles align along an extended interzonal spindle within the narrow isthmus between segregating progeny nuclei. The nuclear division inD. mimosa can be described as closed intranuclear mitosis with acentric and separate microtubular bundles and weakly condensed chromosomes.
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Abbreviations
- MTOC:
-
microtubule-organizing center
References
Breunig A, König H, Brugerolle G, Vickerman K, Hertel H (1993) Isolation and ultrastructural features of a new strain ofDimastigella trypaniformis Sandon 1928 (Bodonina, Kinetoplastida) and comparison with a previously isolated strain. Eur J Protistol 29: 416–424
Croft SL (1979) Ultrastructural study of the nucleus ofLeishmania hertigi. Protistologica 15: 103–110
Ersfeld K, Gull K (1997) Partitioning of large and minichromosomes inTrypanosoma brucei. Science 276: 611–614
Frolov AO, Karpov SA (1995) Comparative morphology of kinetoplastids. Tsitologiya St Petersburg 37: 1072–1096
— —, Malysheva MN (1996) The ultrastructure of mitosis in the free living kinetoplastidBodo curvifilus. Eur J Protistol 32: 498–505
— —, Mylnikov AP, Malysheva MN (1997a) Description and electron-microscopical study of the free-living cryptobiid flagellateDimastigella mimosa sp. n. (Kinetoplastida, Cryptobiidae). Tsitologiya St Petersburg 39: 442–448
—, Malysheva MN, Podlipaev SA, Skarlato SO (1997b) Promastigotes of the trypanosomatidsEndotrypanum monterogei, Leishmania tarentolae andPhytomonas sp.: a comparative microscope study of interphase and mitotic nuclei. Tsitologiya St Petersburg 39: 278–284
Heath IB (1980) Variant mitoses in lower eukaryotes: indicators of the evolution of mitosis? Int Rev Cytol 64: 1–80
Maslov DA, Elgort MG, Wong S, Peckova H, Lom J, Simpson L, Campbell DA (1993) Organization of mini-exon and 5S rRNA genes in the kinetoplastidTrypanoplasma borreli, Mol Biochem Parasitolol: 127–135
Paulin JJ (1975) Intranuclear microtubules in dividingTrypanosoma equiperdum. BioSystems 7: 308
Pickett-Heaps JD (1986) Mitotic mechanisms: an alternative view. Trends Biochem Sci 11: 504–507
Raikov IB (1994) The diversity of forms of mitosis in Protozoa: a comparative review. Eur J Protistol 30: 253–269
Schlegel M (1994) Molecular phylogeny of eukaryotes. Trends Ecol Evol 9: 330–335
Skarlato SO (1987) Fine-structural peculiarities of the nucleus of the parasitic flagellateTrypanoplasma borreli (Kinetoplastidea) during the interphase and mitosis. Dokl Akad Nauk SSSR 293: 220–221
—, Lom J (1997) Mitosis in the flagellateTrypanoplasma borreli (Kinetoplastidea: Bodonida). Eur J Protistol 33: 77–86
— —, Nohýnková E (1987) Fine structural morphology of the nucleus ofTrypanosoma danilewskyi (Kinetoplastida, Trypanosomatina) during mitosis. Arch Protistenkd 133: 3–14
—, Parshkova TA, Frolov AO (1990) Electron microscope and molecular biology investigations of the nucleus in the lower trypanosomatids,Blastocrithidia miridarum andCrithidia brevicula. Tsitologiya Leningrad 32: 317–324
Solari AJ (1980) The 3-dimensional fine structure of the mitotic spindle inTrypanosoma cruzi. Chromosoma 78: 239–255
— (1983) The ultrastructure of mitotic nuclei ofBlastocrithidia triatomae. Z Parasitenk 69: 3–15
— (1995) Mitosis and genome partition in trypanosomes. Biocell 19: 65–84
—, Tandler CJ, Duschak V (1985) Fine structure and cytochemistry of the mitotic plaques ofTrypanosoma cruzi andCrithidia fasciculata. J Submicrosc Cytol 17: 583–591
Somova NV, Skarlato SO, Frolov AO (1997) Chromosomes of free-living kinetoplastid flagellates. Dokl Akad Nauk Rus 357: 405–408
Triemer R, Farmer M (1991) An ultrastructural comparison of the mitotic apparatus, feeding apparatus, flagellar apparatus and cytoskeleton in euglenoids and kinetoplastids. Protoplasma 164: 91–104
—, Fritz LM, Herman R (1986) Ultrastructural features of mitosis inLeishmania adleri. Protoplasma 134: 154–162
Ureña F (1986) Three-dimensional reconstructions of the mitotic spindle and dense plaques in three species ofLeishmania. Z Parasitenk 72: 299–306
Vanhamme L, Pays E (1995) Control of gene expression in trypanosomes. Microbiol Rev 59: 223–240
Vickerman K (1991) Organization of the bodonid flagellates. In: Patterson DJ, Larsen J (eds) The biology of free-living heterotrophic flagellates. Clarendon Press, Oxford, pp 159–176 (The Systematics Association special volume, vol 45)
— (1994) The evolutionary expansion of the trypanosomatid flagellates. Int Parasital 24: 1317–1331
—, Preston TM (1970) Spindle microtubules in the dividing nuclei of trypanosomes. I Cell Sci 6: 365–383
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Frolov, A.O., Skarlato, S.O. Unusual pattern of mitosis in the free-living flagellateDimastigella mimosa (Kinetoplastida). Protoplasma 201, 101–109 (1998). https://doi.org/10.1007/BF01280716
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DOI: https://doi.org/10.1007/BF01280716