Microsurgical analysis of the clonal age and the cell-cycle stage required for the onset of autogamy in Paramecium tetraurelia

Mikami, K.; Koizumi, Sadaaki

doi:10.1016/0012-1606(83)90203-8

Cited by 24 publications

(8 citation statements)

References 10 publications

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“…Accordingly, maintenance of the ability to produce the 0 factor production seems to depend on the rounds of DNA synthesis but not on the absolute time. A similar hypothesis has been postulated for the timing of the clonal age at which autogamy can be induced [19]. As was mentioned above, it has been assumed that the E cytoplasmic factor determines the new postzygotic macronuclei in the first cell cycle, 10-11 hr after the sensitive period of macronuclear origin from a product of the synkaryon.…”

Section: Discussionmentioning

confidence: 88%

Analysis of mating type determination by transplantation of O macronuclear karyoplasm in Paramecium tetraurelia

1986

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The odd (0) or even (E) mating type in Paramecium tetruurelia is determined during the first cell cycle after new macronuclear development. The present paper demonstrates that mating type E is irreversibly determined at the end of the first cell cycle. Direct evidence comes from transplanting 0 macronuclear karyoplasm containing 0-determining factor into E autogamous cells during a new postzygotic macronuclear development. Transplantation of 0 macronuclear karyoplasm into E autogamous cells at 7-8 hr after the origin of the macronucleus from a product of the synkaryon produces nearly 100% 0 mating type among the exautogamous cell lines but almost none 10-11 hr after the origin of the macronucleus (around the end of the first cell cycle). The macronuclear anlagen at the stage at which mating type E seems to be fixed contains about 20 times as much DNA as the vegetative G1 micronucleus. The 0-determining factor shifting E cells toward 0 mating type by transplanting 0 macronuclear karyoplasm is also produced by the newly developed macronucleus in an effective concentration at 10-11 hr after the sensitive period and produced at full levels by the third cell cycle. The level of 0 factor in the macronucleus then gradually declines with subsequent repeated rounds of DNA synthesis and is finally lost by the eighth cell cycle.

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Section: Discussionmentioning

confidence: 88%

Analysis of mating type determination by transplantation of O macronuclear karyoplasm in Paramecium tetraurelia

1986

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“…Commitment of the cell to autogamy (uniparental self-fertilization), during which the micronuclei undergo meiosis, is made in two steps upon nutritional down-shift (Mikami & Koizumi, 1983;Berger, 1986). Commitment of the cell to autogamy (uniparental self-fertilization), during which the micronuclei undergo meiosis, is made in two steps upon nutritional down-shift (Mikami & Koizumi, 1983;Berger, 1986).…”

Section: ( I ) the Cell Cycle Boundary Is Not A Developmental Barriermentioning

confidence: 99%

“…The situation with commitment to sexual development is similar. Commitment of the cell to autogamy (uniparental self-fertilization), during which the micronuclei undergo meiosis, is made in two steps upon nutritional down-shift (Mikami & Koizumi, 1983;. The initial commitment occurs at about 0.75 of the preceding cell cycle, prior to cytokinesis (the pre-autogamous cell fission).…”

Section: ( I ) the Cell Cycle Boundary Is Not A Developmental Barriermentioning

confidence: 99%

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

1990

Biological Reviews

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“…Its duration expressed as the number of fissions (SMITH-SONNEBORN & REED 1976), is a stable and characteristic trait for species and even for stocks (KOOECIUSZKO & PRA-JER 1988;PRAJER & KOOECIUSZKO 1999). This trait is genetically controlled by the macronucleus and can be experimentally accelerated (MIKAMI & KOIZUMI 1983;KOOECIUSZKO & PRAJER 1989). The isolation of mutants with a short period of autogamous immaturity (TAKAGI et al 1987(TAKAGI et al , 1989 as well as with a long one (KOMORI et al 2004) confirmed the role of the macronucleus in the regulation of IAI duration.…”

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confidence: 99%

Glucose, Sorbitol and Insulin as Exogenous Agents that Monitor the Interautogamous Interval (IAI) in Paramecium primaurelia

Prajer¹

2005

folia biol (krakow)

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Results from previous studies have revealed that the duration of the interautogamous interval (IAI), expressed as the number of fissions occurring between two successive autogamies, is stable and characteristic for species of the Paramecium aurelia complex (KOOECIUSZKO & PRAJER 1988; PRAJER & KOOECIUSZKO 1999). The duration of the IAI is genetically controlled (KOOECIUSZKO & PRAJER 1989; MIKAMI & KOIZUMI 1983). Genomic mutations (PRAJER & KOOECIUSZKO 1999; TAKAGI et al. 1989) as well as disturbances of morphological homeostasis of the cell, as observed in Paramecium doublets (PRAJER et al. 1999), shorten the duration of the IAI. This suggests that epigenetic factors may accelerate the induction of autogamy. The aim of this study was to search for environmental, exogenous factors which may affect the IAI duration. The first investigated factor was glucose used in such a concentration which did not change the rate of vegetative cell divisions. The second tested factor was sorbitol used as nonmetabolized sugar and applied at a similar concentration as glucose to verify a possible osmotic effect. Both these factors accelerated the induction of autogamy and shortened IAI duration in Paramecium primaurelia. An insulin hormone was also used as a candidate for a sugar dependent factor complementary to glucose. It also resulted in acceleration of autogamy induction. It was chosen to test its effect on IAI since the existence of an insulin receptor in Tetrahymena has been reported (CHRISTENSEN et al. 2003). This hormone peptide also induced an IAI shortening. The results of a search in the Ciliates genome for potential homologs of genes coding insulin receptors and insulin itself, as well as hypothetical mechanisms of action of investigated agents were discussed.

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Microsurgical analysis of the clonal age and the cell-cycle stage required for the onset of autogamy in Paramecium tetraurelia

Cited by 24 publications

References 10 publications

Analysis of mating type determination by transplantation of O macronuclear karyoplasm in Paramecium tetraurelia

Analysis of mating type determination by transplantation of O macronuclear karyoplasm in Paramecium tetraurelia

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Glucose, Sorbitol and Insulin as Exogenous Agents that Monitor the Interautogamous Interval (IAI) in Paramecium primaurelia

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