Abstract
The vegetative nuclear division inPenicillium differs from classical mitosis, and a model for the division process is presented. In early divisional stages the interconnected chromosomes are arranged in a ring which breaks, giving rise to a linear configuration which divides by longitudinal splitting. The break may occur with equal probability between each of the chromosomes. At the end of the division process the daughter nuclei regain ring structure. One of the chromosomes is believed to represent a separation center for all the chromosomes. In diploid strains the two haploid genomes show a close somatic association and the nuclear configurations occurring during the divisional cycle are identical to those in the haploids. The double break of the ring structures in diploids will give recombinant nuclei in certain cases. The model explains the available data of the parasexual cycle, and both diploidization and haploidization are believed to represent singlestep processes.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barron G. L. (1962). The parasexual cycle and linkage relationships in the storage root fungusPenicillium expansum.Canad. J. Bot. 40: 1603–1614.
Buxton E. W. (1956). Heterocaryosis and parasexual recombination in pathogenic strains ofFusarium oxysporum.J. Gen. Microbiol. 15: 133–139.
DeLamater E. D. (1948). The nuclear cytology ofBlastomyces dermatitides.Mycologia 40: 430–444.
Dodge B. O., J. R. Singleton & A. Rolnick (1950). Studies of lethal E gene inNeurospora tetrasperma, including chromosome counts also in races ofNeurospora sitophila.Proc. Amer. Phil. Soc. 94: 38–52.
Fjeld A. & Ö Strømnæs (1966). The parasexual cycle and linkage groups inPenicillium expansum.Hereditas 54: 389–403.
Garber E. D. & L. Beraha (1965). Genetics of phytopathogenetic fungi. XIV. The parasexual cycle inPenicillium expansum.Genetics 52: 487–492.
Girbardt, M. (1968). Ultrastructure and dynamics of the moving nucleus. In: Aspects of Cell Motility (Cambrigde University Press).22nd Symp. Soc. Exper. Biol. Oxford: 249–259.
Hastie A. C. (1964). The parasexual cycle inVerticillium alboatrum.Genet. Res. 5: 305–315.
Heale J. B., A. Gafoor & K. C. Rajasingham (1968). Nuclear division in conidia and hyphae ofVerticillium albo-atrum.Canad. J. Genet. Cytol. 10: 321–340.
Hejtmanek M. & N. Hejtmanekova-Uhrova (1968). Vegetative nuclei and differentiation of chromosomes inTrichophyton vanbreusehemii.Folia Microbiologica 13: 410–413.
Ishitani C., Y. Ikeda & K. Sakagushi (1956). Hereditary variation and genetic recombination in Kolji-molds (Aspergillus oryzae andAsp. sojae). VI. Genetic recombination in heterozygous diploid.J. Gen. Appl. Microbiol. (Japan)2: 401–430.
Käfer E. (1961). The processes for spontaneous recombination in vegetative nuclei ofAsperigillus nidulans.Genetics 46: 1581–1609.
Laane M. M. (1967). The nuclear division inPenicillium expansum.Canad. J. Genet. Cytol. 9: 342–351.
Laane M. M. (1969). Further cytological studies in the genusPenicillium Link.Hereditas 62: 153–184.
Laane M. M. (1970). Meiosis and ascus formation inPenicillium striatum.Hereditas 65: 133–158.
Lu B. C. (1962). A new fixative and improved propionocarmine squash technique for staining fungus nuclei.Canad. J. Bot. 40: 843–847.
McClintock B. (1945).Neurospora, I. Preliminary observations on the chromosomes ofNeurospora crassa.Amer. J. Bot. 32: 671–678.
Nambodiri A. N. & R. J. Lowry (1967). Vegetative nuclear division inNeurospora.Amer. J. Bot. 54: 735–748.
Olive L. S. (1953). The structure and behaviour of fungus nuclei.Botan. Rev. 19: 439–586.
Pontecorvo G. & E. Käfer (1958). Genetic analysis by means of mitotic recombination.Advan. Genet. 9: 71–104.
Pontecorvo, G., & J. A. Roper (1952). Genetic analysis without sexual reproduction by means of polyploidy inAspergillus niger. J. Gen. Microbiol. 6 VII (Abstr.).
Pontecorvo G., J. A. Roper & E. Forbes (1953). Genetic recombination without sexual reproduction inAspergillus niger.J. Gen. Microbiol. 8: 198–210.
Pontecorvo G. & G. Sermonti (1954). Parasexual recombination inPenicillium chrysogenum.J. Gen. Microbiol. 11: 94–104.
Raper J. R. & K. Esser (1964). The Fungi. In: J. Brachet & A. E. Mirsky: “The Cell”. Academic Press, New York vol.6: 139–244.
Singleton J. R. (1953). Chromosome morphology and the chromosome cycle in the ascus ofNeurospora crassa.Amer. J. Bot. 40: 124–144.
Somers C. E., R. P. Wagner & T. G. Hsu (1960). Mitosis in vegetative nuclei ofNeurospora crassa.Genetics 45: 801–810.
Strømnæs Ø., E. D. Garber & L. Beraha (1964). Genetics of phytopathogenic fungi. IX. Heterocaryosis and the parasexual cycle inPenicillium italicum andPenicillium digitatum.Canad. J. Bot. 42: 423–427.
Tinline R. D. (1962).Cochliobolus sativus. V. Heterocaryosis and parasexuality,Canad. J. Bot. 40: 425–437.
Tuveson R. W. & D. O. Coy (1961). Heterocaryosis and somatic recombination inCephalosporium mycophyllum.Mycologia (N.Y.)53: 244–253.
Ward E. W. B. & K. W. Chiurysek (1962) Somatic mitosis inNeurospora.Amer. J. Bot. 49: 393–399.
Weijer J., A. Koopmans & D. L. Weijer (1965). Karyokinesis of somatic nuclei ofNeurospora crassa. III. The juvenile and maturation cycles. (Feulgen and crystal violet staining).Canad. J. Genet. Cytol. 7: 140–163.
Weijer J. & S. H. Weisberg (1966). Karyokinesis of the somatic nucleus ofAspergillus nidulans. I. The juvenile chromosome cycle (Feulgen staining).Canad. J. Genet. Cytol. 8: 361–374.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Fjeld, A., Laane, M.M. The nuclear division and parasexual cycle inPenicillium . Genetica 41, 517–524 (1970). https://doi.org/10.1007/BF00958930
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00958930