Abstract
During asexual fission in the ciliate Euplotes eurystomus, the macronucleus divides amitotically. The macronucleus was found to divide unequally, yielding sister pairs having a mean difference in DNA content of 11.6%. DNA content was determined by the Feulgen reaction using a fluorescent Schiffs reagent, and measuring fluorescence by cytophotometry. Variability in macronuclear DNA content was also examined in randomly-paired non-sister cells, and found to be greater than in sister cells. This greater variability could be due to accumulation of differences over a number of divisions, or to interclonal differences in equality of division. Two categories of non-sister cells were examined: recently divided, and “parents” constructed by averaging the DNA contents of progeny. Both showed similar variability in quantity of macronuclear DNA. The fact that cells surviving to divide showed no less variability in amount of DNA than cells immediately after division suggests that extremes in amounts of DNA resulting from unequal division are not selected against.
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References
Allen, S., Gibson, I.: Genome amplification and gene expression expression in the ciliate macronucleus. Biochem. Genet. 6, 293–313 (1972)
Ammermann, D.: Morphology and development of the macronucleus of the ciliates Stylonychia mytilus and Euplotes aediculatus. Chromosoma (Berl.) 33, 209–238 (1971)
Ammermann, D., Steinbruck, G., Berger, L. von, Hennig, W.: The development of the macronucleus in the ciliated protozoan Stylonychia mytilus. Chromosoma (Berl.) 45, 401–429 (1974)
Cleffman, G.: Regulierung der DNS-Menge im Makronucleus von Tetrahymena. Exp. Cell Res. 50, 193–207 (1968)
Doerder, F. P., DeBault, L. E.: Cytofluorimetric analysis of nuclear DNA during meiosis, fertilization and macronuclear development in the ciliate Tetrahymena pyriformis, syngen 1. J. Cell Sci. 17, 471–489 (1975)
Gall, J.G.: Macronuclear duplication in the ciliated protozoan Euplotes. J. biophys. biochem. Cytol. 5, 295–308 (1959)
Hawes, R.S.J.: An adhesion technique for small aquatic organisms. J. roy. micr. Soc. 82, 225–227 (1963)
Kimball, R.F., Barka, T.: Quantitative cytochemical studies on Paramecium aurelia. II. Feulgen microspectrophotometry of the macronucleus during exponential growth. Exp. Cell Res. 17, 173–182 (1959)
Kimball, R.F., Prescott, D.M.: DNA synthesis and distribution during growth and amitosis of the macronucleus of Euplotes. J. Protozool. 9, 88–92 (1962)
Kloetzel, J.A.: Compartmentalization of the developing macronucleus following conjugation in Stylonychia and Euplotes. J. Cell Biol. 47, 395–407 (1970)
McDonald, B.B.: Quantitative aspects of DNA metabolism in an amicronucleate strain of Tetrahymena. Biol. Bull. 114, 71–94 (1958)
Nyberg, D.: Are macronuclear subunits in Paramecium functionally diploid? Genet. Res. (Camb.) 27, 239–248 (1976)
Orias, E., Flacks, M.: Macronuclear genetics of Tetrahymena I. Random distribution of macronuclear gene copies in T. pyriformis, syngen 1. Genetics 79, 187–206 (1975)
Freer, J.R. Jr.: Quantitative predictions of random segregation models of the ciliate macronucleus. Genet. Res. (Camb.) 27, 227–238 (1976)
Prescott, D.M.: The syntheses of total macronuclear protein, histone and DNA during the cell cycle in Euplotes eurystomus. J. Cell Biol. 31, 1–9 (1966)
Prescott, D.M., Bostock, C.J., Murti, K.G., Lauth, M.R., Gamow, E.: I. Electron microscopic and sedimentation analysis of macronulcear and micronuclear DNA of Stylonychia mytilus. Chromosoma (Berl.) 34, 355–366 (1971)
Prescott, D.M., Murti, K.G., Bostock, C.J.: The genetic apparatus of Stylonychia sp. Nature (Lond.) 242, 596–600 (1973)
Prescott, D.M., Rao, M.V.N., Evenson, D.P., Stone, G.E., Thrasher, J.D.: Isolation of single nuclei and mass preparations of nuclei from several cell types. In: Methods in cell physiology (D.M. Prescott, ed.), Vol. 2, pp. 131–142. New York: Academic Press 1966
Prescott, D.M., Stone, G.E.: Replication and function of the protozoan nucleus. In: Research in protozoology (T.T. Chen, ed.), Vol. 2, pp. 117–146. New York: Pergamon Press 1967
Raikov, I.B.: The macronucleus of ciliates. In: Research in protozoology (T.T. Chen, ed.), Vol. 3, pp. 1–128. New York: Pergamon Press 1969
Ruch, F.: DNA content by microfluorimetry. In: Introduction to. quantitative cytochemistry (G.L. Wied, ed.), pp. 281–294. New York: Academic Press 1966
Ruffolo, John J. Jr.: Fine structure of cell development in Euplotes. Ph.D. Thesis, University of Iowa, Department of Zoology (1972)
Ruffolo, J.J. Jr.: Cortical morphogenesis during the cell division cycle in Euplotes: an integrated study using light optical, scanning electron and transmission electron microscopy. J. Morph. 148, 489–528 (1976)
Ruthmann, A.: Autoradiographische und Mikrophotometrische Untersuchungen zur DNS-Synthese im Macronucleus von Bursaria truncatella. Arch. Protistenk. 107, 117–130 (1964)
Ruthmann, A., Hauser, M.: Mitosis-like macronuclear division in a ciliate. Chromosoma (Berl.) 45, 261–272 (1974)
Tamura, S., Tsuruhara, R., Watanabe, Y.: Function of nuclear microtubules in macronuclear division of Tetrahymena pyriformis. Exp. Cell Res. 55, 351–358 (1969)
Tomonaga, S., Nomura, A., Awaya, K.: Optimal Feulgen hydrolysis for microspectrophotometry. Acta histochem. cytochem. 4, 166–172 (1971)
Wesley, R.D.: Inverted repetitious sequences in the macronuclear DNA of hypotrichous ciliates. Proc. nat. Acad. Sci. (Wash.) 72, 678–682 (1975)
Williams, N.E.: Regulation of microtubules in Tetrahymena. Int. Rev. Cytol. 41, 59–86 (1975)
Williams, N.E., Williams, R.J.: Macronuclear division with and without microtubules in Tetrahymena. J. Cell Sci. 20, 61–77 (1976)
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Witt, P.L. Unequal distribution of DNA in the macronuclear division of the ciliate Euplotes eurystomus . Chromosoma 60, 59–67 (1977). https://doi.org/10.1007/BF00330411
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DOI: https://doi.org/10.1007/BF00330411