Induction of conjugation by chemical agents in <i>Paramecium</i>

Miyake, Akio

doi:10.1002/jez.1401670308

Cited by 61 publications

(22 citation statements)

References 24 publications

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“…Chemical induction of conjugation has previously not been successfully achieved in members of the "bursaria" group of Paramecium species, except for one selfing strain in P. trichium (Miyake, 1968). In the work reported here, 36 stocks were examined ( Kitamura (1982Kitamura ( , 1984 reported that mating reactive cells of Paramecium tend to attach on hydrophobic surfaces such as the polystyrene surface and suggested that some kind of hydrophobic interactions on ciliary membranes is involved in the early step of the induction of conjugation.…”

Section: Discussionmentioning

confidence: 88%

“…In these cell unions, exchange of gamete nuclei is blocked because of the failure of face-to-face adhesion of paroral regions and fusion of identical haploid nuclei occurs, leading to the production of completely homozygous progeny, like those found after autogamy (Miyake, 1968). Though many species of Paramecium have been shown to undergo chemically induced conjugation, this has not previously been reported for Paramecium bursaria.…”

Section: Introductionmentioning

confidence: 94%

“…Chemical induction of conjugation was carried out according to the methods of Miyake (1958Miyake ( , 1968. Mating reactive cells cultured in Ca-poor medium were washed twice and suspended in physiological balanced solution (PBS) containing l5 mM NaC1, 005 mM KC1, 01 mM MgCI2 and 001 mM CaCI2 in 2 mM phosphate buffer (pH 6.4).…”

Section: Chemical Induction Of Conjugationmentioning

confidence: 99%

“…In normal conjugation, interaction of cells of complementary mating types activates the cells for pair formation. The other means of inducing conjugation is called the chemical induction of conjugation and was developed by Miyake (1958Miyake ( , 1968. In this type of conjugation, cells are activated for pair formation without the interaction of cells of complementary mating types.…”

Section: Introductionmentioning

confidence: 99%

“…induced chemically, aberrant cell unions often occur (Miyake, 1958). In these cell unions, exchange of gamete nuclei is blocked because of the failure of face-to-face adhesion of paroral regions and fusion of identical haploid nuclei occurs, leading to the production of completely homozygous progeny, like those found after autogamy (Miyake, 1968).…”

Section: Introductionmentioning

confidence: 99%

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Genetic control of chemical induction of conjugation in Paramecium bursaria

Endoh

1987

Heredity

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In six out of 36 natural stocks of Paramecium bursaria examined, chemical induction of conjugation was successful when cells were cultured in Ca-poor medium and then treated with acriflavine and KCI. Conjugation by the normal process following mixing of cells of opposite mating type occurred normally in these six stocks. Genetic analysis of chemical induction of conjugation was performed with three out of the six stocks. Chemical induction of conjugation was found to be controlled by recessive genes at two different loci, designated cic-1, cic-2. These genes are not linked to mating type loci. These inducible stocks showed additional features different from those of uninducible ones. When uninducible stocks were stimulated both by mating reaction and conjugation-inducing chemicals simultaneously, conjugation was drastically inhibited. Inducible stocks, by contrast, were free from such inhibition. The results suggest that there is a step blocked by the conjugation-inducing chemicals in the normal process of conjugation. This step is probably controlled by the cic loci.

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 94%

Section: Chemical Induction Of Conjugationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Genetic control of chemical induction of conjugation in Paramecium bursaria

Endoh

1987

Heredity

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A genetic system for alternative stable characteristics in genomically identical homozygous clones

Sonneborn

Schneller

1979

Dev. Genet.

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Paramecium tetraurelia, stock d 1 13, although completely homozygous, produces t w o kinds of genomically identical clones: N (nondischarge) clones incapable of trichocyst exocytosis (discharge) from intact cells in response t o picric acid; and D (discharge) $ones that d o respond. These alternatives are irreversibly determined (at 27 C) during a determination sensitive period the first day after fertilization (autogamy, conjugation, or cytogamy): D parents are always determined t o produce D progeny; N parents produce mostly N progeny if kept in exhausted medium, but mostly D progeny if kept in bacterized nutrient medium, throughout the sensitive period. If connecting bridges between mates persist long after the time for pair separation, t h e N member of N X D conjugant and cytogamous pairs produces D progeny even if exposed t o exhausted medium throughout t h e sensitive period, thus indicating the presence in D mates of a D-determining cytoplasmic factor,A, which overrides effects of external conditions. N and D determinations are brought about o n newly developing somatic nuclei (macronuclear anlagen). After macronuclear development has been completed, determination is irreversible in it and its descendant macronuclei. M (mixed) clones produce N , D, and partial D cells; within these clones, diverse subclones can be selected. Crosses of d113 (N) X standard wild stock 5 1 (D) yield n o segregation in F,, indicating no genomic difference between d113 (N) and wild t y p e (D). A may be a genic product regulating its o w n production. This results in "cytoplasmic inheritance" of D vs N in crosses of D X N followed by exhausted medium during t h e sensitive period. As with t h e only other well-analyzed comparable example, mating types, neither a genetic nor an epigenetic interpretation has yet been excluded for this system of developmental differentiation. Sonneborn and Schneller INTRODUCTIONWe present in this paper an example of alternative hereditary phenotypes in cell lineages that have identical and completely homozygous genotypes and that are cultured under identical external conditions. These hereditary alternatives are nevertheless determined by the nucleus as nuclear differentiations that can be brought about only during a limited period of less than one day in tlie whole clonal life cycle, a period responsive to irreversible determining action of external and internal factors. We intend to report further study and analysis of each of the features of this system in a series of later papers. Here we attempt to give only an overview of the system with supporting data.The chief interest of systems of this kind lies in their phenomenological similarity to those normal cellular differences that commonly arise during development of multicellular animals and are highly stable during long culture as explants. The existence o f at least superficially similar clonal systems in unicellular organisms has long been known and has been frequently reviewed [ 1-91 . To the extent that underlying mechanisms have been d...

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Control of mating type expression in Paramecium multimicronucleatum, syngen 2

Clark

1972

Journal Cellular Physiology

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Two isogenic acyclic strains of Paramecium multimicronucleatzlm, syngen 2 , expressing mating types 111 and IV, and a cycler strain, which displays circadian alternation of the two mating types, were treated with proteolytic enzymes, or the inhibitors actinomycin D or puromycin at various stages of the mating reactive period induced by food depletion. Reactivity of acyclic animals was sensitive to proteolytic enzymes, and to both inhibitors before or after the onset of reactivity, suggesting that reactivity is attained and maintained via continuous RNA and protein synthesis, and that protein integrity is essential to the activity of the type-specific substances. A new cell cycle was not necessary for recovery from a block in reactivity.Type I11 animals were consistently more sensitive to inhibition by puromyin, and required longer recovery periods after all treatments except actinomycin D given after the development of reactivity. Possible explanations of these observations are considered.The daily type changes seen in cycler animals seemed to occur by replacement of one mating type substance with the other. Type-switching was neither prevented nor displaced by exposure to actinomycin D or puromycin during a period before or including a type change, even though reactivity was reduced by more than 95%, suggesting that type-switching is not directly associated with transcription or translation of the type-specific genes.

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Induction of conjugation by chemical agents in Paramecium

Cited by 61 publications

References 24 publications

Genetic control of chemical induction of conjugation in Paramecium bursaria

Genetic control of chemical induction of conjugation in Paramecium bursaria

A genetic system for alternative stable characteristics in genomically identical homozygous clones

Control of mating type expression in Paramecium multimicronucleatum, syngen 2

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