Abstract
Mitotic micronuclei were isolated from Tetrahymena thermophila in a medium containing hexylene glycol and their ultrastructure was analyzed using thin section techniques. The two stages selected for analysis were early prometaphase and metaphase. A comparison of data from these two stages revealed several differences in nuclear morphology. Metaphase nuclei were longer, they contained more microtubules, and the distribution of microtubules at metaphase was different from that at early prometaphase. Increases in microtubule number and length were clearly evident in peripheral sheath microtubules, which are a unique class of microtubules that can be distinguished from other classes on the basis of their close association to the nuclear membrane. Growth of peripheral sheath microtubules is thought to be significant because it could be the mechanical basis of nuclear elongation. Crossbridges were observed throughout the spindle between all classes of microtubules, but the exact function of these elements remains to be determined.
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Bajer, A., Molé-Bajer, J.: Formation of spindle fibers, kinetochore orientation, and behavior of the nuclear envelope during mitosis in endosperm. Fine structure and in vitro studies. Chromosoma (Berl.) 27, 448–484 (1969)
Davidson, L., LaFountain, J.R., Jr.: Mitosis and early meiosis in Tetrahymena pyriformis and the evolution of mitosis in the phylum Ciliophora. BioSystems 7, 326–336 (1978)
Dietz, R.: Die Spermatocytenteilungen der Tipuliden. II. Graphische Analyse der Chromosomenbewegung während der Prometaphase I im Leben. Chromosoma (Berl.) 8, 183–211 (1956)
Fuge, H.: Ultrastructure of the mitotic spindle. Int. Rev. Cytol. Suppl. 6, 1–58 (1977)
Gavin, R.H.: The effects of heat and cold on cellular development in synchronized Tetrahymena pyriformis WH-6. J. Protozool. 12, 307–318 (1965)
Gould, R.R., Borisy, G.G.: The pericentriolar material in Chinese hamster ovary cells nucleates microtubule formation. J. Cell Biol. 73. 601–615 (1977)
Gould, R.R., Borisy, G.G.: Quantitative initiation of microtubule assembly by chromosomes from Chinese hamster ovary cells. Exp. Cell Res. 113. 369–374 (1978)
Henderson, S.A., Koch, C.A.: Co-orientation stability by physical tension: A demonstration with experimentally interlocked bivalents. Chromosoma (Berl.) 29, 207–216 (1970)
Hepler, P.K., McIntosh, J.R., Landis, S.C.: Intermicrotubule bridges in mitotic spindle apparatus. J. Cell Biol. 45, 438–444 (1970)
Kane, R.E.: The mitotic apparatus. Physical-chemical factors controlling stability. J. Cell Biol. 25, 137–144 (1965)
Kirschner, M.W.: Microtubule assembly and nucleation. Int. Rev. Cytol. 54, 1–71 (1978)
LaFountain, J.R., Jr.: Spindle shape changes as an indicator of force production in crane-fly spermatocytes. J. Cell Sci. 10, 79–93 (1972)
LaFountain, J.R., Jr.: Birefringence and fine structure of spindles in spermatocytes of Nephrotoma suturalis at metaphase of first meiotic division. J. Ultrastruct. Res. 46, 268–278 (1974)
Luykx, P.: Cellular mechanisms of chromosome distribution. Int. Rev. Cytol., Suppl. 2, (1970)
McDonald, K., Pickett-Heaps, J.D., McIntosh, J.R., Tippit, D.H.: On the mechanism of anaphase spindle elongation in Diatoma vulgare. J. Cell Biol. 74, 377–388 (1977)
McIntosh, J.R.: Bridges between microtubules. J. Cell Biol. 61, 661–187 (1974)
Mollenhauer, H.H.: Plastic embedding for use in electron microscopy. Stain Technol. 39, 111–114 (1964)
Nicklas, R.B.: Chromosome distribution: Experiments on cell hybrids and in vitro. Phil. Trans. roy. Soc. Lond. B 277, 267–276 (1977)
Nicklas, R.B., Brinkley, B.R., Pepper, D.A., Kubai, D.F., Rickards, G.K.: Electron microscopy of spermatocytes previously studied in life: Methods and some observations on manipulated chromosomes. J. Cell Sci. 35, 87–104 (1979)
Paweletz, N.: Elektronenmikroskopische Untersuchungen an frühen Stadien der Mitose bei HeLa-Zellen. Cytobiologie 9, 368–390 (1974)
Pickett-Heaps, J.D.: The evolution of the mitotic apparatus: An attempt at comparative ultrastructural cytology in dividing plant cells. Cytobios. 1, 257 (1969)
Pickett-Heaps, J.D.: The evolution of mitosis and the eukaryotic condition. BioSystems 6, 37–48 (1974)
Pickett-Heaps, J.D., Tippit, D.H.: The diatom spindle in perspective. Cell 14, 455–467 (1978)
Roos, U.-P.: Light and electron microscopy of rat kangaroo cells in mitosis. III. Patterns of chromosome behavior during prometaphase. Chromosoma (Berl.) 54, 363–385 (1976)
Sakai, A.: Electron microscopy of dividing cells I. Microtubules and the formation of the spindle in spore mother cells of Equisetum arvense. Cytologia (Tokyo) 33, 318–330 (1968)
Sakai, A.: Electron microscopy of dividing cells II. Microtubules and formation of the spindle in root tips of higher plants. Cytologia (Tokyo) 34, 57–70 (1969a)
Sakai, A.: Electron microscopy of dividing cells III. Mass of microtubules and formation of spindle in pollen mother cells of Trillium kamtschaticum. Cytologia (Tokyo) 34, 593–604 (1969b)
Summers, K.E., Gibbons, I.R.: Adenosine triphosphase-induced sliding of tubules in trypsin-treated flagella of sea-urchin sperm. Proc. nat. Acad. Sci. (Wash.) 68, 3092–3096 (1971)
Telzer, B.R., Moses, M.J., Rosenbaum, J.L.: Assembly of microtubules onto kinetochores of isolated mitotic chromosomes of HeLa cells. Proc. nat. Acad. Sci. (Wash.) 72, 4023–4027 (1975)
Tilney, L.G.: Origin and continuity of microtubules. IN. Origin and continuity of cell organelles. (J. Reinert and H. Urspring, eds.), pp. 222–260. Berlin, Heidelberg, New York: Springer 1971
Tippit, D.H., Schulz, D., Pickett-Heaps, J.D.: Analysis of the distribution of spindle microtubules in the diatom, Fragilaria. J. Cell Biol. 79, 737–763 (1978)
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LaFountain, J.R., Davidson, L.A. An analysis of spindle ultrastructure during prometaphase and metaphase of micronuclear division in Tetrahymena . Chromosoma 75, 293–308 (1979). https://doi.org/10.1007/BF00293473
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DOI: https://doi.org/10.1007/BF00293473