A gamma ray-induced non-excitable membrane mutant in Paramecium caudatum: a behavioral and genetic analysis

SUMMARYA new CNR (caudatum non-reversal) mutant of Paramecium caudatum was isolated after gamma ray mutagenesis. This CNR lacks not only the transient inward Ca2+ current but also the sustained Ca2+ current. It was shown to complement the three known CNR mutants of P. caudatum (cnrA, cnrB and cnrC) by crossbreeding analyses. Thus, this new mutant belongs to a 4th CNR locus, designated cnrD. The defect of cnrD can be partially rescued by microinjection of cytoplasm from any of the three CNR mutants or the three Pawns (pwA, pwB and pwC) in P. tetraurelia. Since the three CNR genes have been shown to be different from the three Pawn genes by cytoplasmic complementation test (Haga et al. 1983), this result suggests that cnrD is the 7th non-excitable mutant in Paramecium. Thus, there are at least seven genes controlling Ca2+ channel function in Paramecium.

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GENES CONTROLLING MATING-TYPE SPECIFICITY IN PARAMECIUM CAUDATUM: THREE LOCI REVEALED BY INTERSYNGENIC CROSSES

Genetics ◽

10.1093/genetics/104.1.41 ◽

1983 ◽

Vol 104 (1) ◽

pp. 41-62

Author(s):

Yuuji Tsukii ◽

Koichi Hiwatashi

Keyword(s):

Genetic Analysis ◽

Mating Type ◽

Pair Formation ◽

High Fertility ◽

Mating Types ◽

Paramecium Caudatum ◽

Multiple Alleles ◽

Behavioral Marker ◽

Species Pairs ◽

Recessive Homozygote

ABSTRACT In mating interactions in Paramecium caudatum, initial mating agglutination is strictly mating-type specific, but subsequent conjugating pair formation is not mating-type specific. Using this nonspecificity of pair formation, intersyngenic (intersibling species) pairs were induced by mixing four mating types of two different syngens. To distinguish intersyngenic pairs from intrasyngenic ones, the behavioral marker CNR (Takahashi 1979) was mainly used. Clones of intersyngenic hybrids showed high fertility and thus made feasible a genetic analysis of syngenic specificity of mating type. The syngenic specificities of E (even) mating types were found to be controlled by co-dominant multiple alleles at the Mt locus, and those of O (odd) mating types by interactions of co-dominant multiple alleles at two loci, MA and MB. Clones of heterozygotes express dual mating types. Mt is epistatic to MA and MB, and thus O mating types can be expressed only in the recessive homozygote (mt/mt) at the Mt locus. In addition, at least one allele each at the MA and MB loci must have a common syngen specificity for the expression of O types. Thus, when MA is homozygous for one syngen and MB is homozygous for another syngen, no mating type is expressed.

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GENETIC ANALYSIS OF GAMMA-RAY MUTAGENESIS IN YEAST. I. REVERSION IN RADIATION-SENSITIVE STRAINS

Genetics ◽

10.1093/genetics/93.2.361 ◽

1979 ◽

Vol 93 (2) ◽

pp. 361-373

Author(s):

Richard H McKee ◽

Christopher W Lawrence

Keyword(s):

Ionizing Radiation ◽

Genetic Analysis ◽

Gamma Ray ◽

Wild Type ◽

Uv Mutagenesis ◽

Major Pathway ◽

Gene Functions ◽

Γ Rays ◽

Γ Ray ◽

Type Strains

ABSTRACT The frequency of revertants induced by 6OCo γ rays of the ochre allele, cyc1-9, has been measured in radiation-sensitive strains carrying one of 19 nonallelic mutations and in wild-type strains. The results indicate that ionizing radiation mutagenesis depends on the activity of the RAD6 group of genes and that the gene functions employed are very similar, but probably not identical, to those that mediate UV mutagenesis. Repair activities dependent on the functions of the RAD50 through RAD57 loci, the major pathway for the repair of damage caused by ionizing radiation, do not appear to play any part in mutagenesis. A comparison between the γ-ray data and those obtained previously with UV (LAWRENCE and CHRISTENSEN 1976) and chemical mutagens (PRAKASH 1976) suggests that the RAD6 "mutagenic pathway" is in fact composed of a set of processes, some of which are concerned with error-prone, and some with error-free, recovery activities.

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Phenotypic conversion of mating type specificity induced by transplantation of macronucleoplasm in Paramecium caudatum

Genetics Research ◽

10.1017/s0016672300032201 ◽

1994 ◽

Vol 63 (2) ◽

pp. 101-107 ◽

Cited By ~ 7

Author(s):

Manabu Hori ◽

Mihoko Takahashi

Keyword(s):

Genetic Analysis ◽

Mating Type ◽

Null Allele ◽

Gene Dosage ◽

The Other ◽

Paramecium Caudatum ◽

Specific Expression ◽

Classical Genetic ◽

Transplantation Technique

SummaryAccording to the classical genetic analysis in Paramecium caudatum by Tsukii & Hiwatashi (1983), the E mating type of each syngen is expressed when the cell bears alleles specific for syngen at the Mt locus. The O mating type is expressed when cells are homozygous for the null allele, mt, at the Mt locus. In such mt/mt cells the O syngen specificity is determined by alleles at two other loci called MA and MB. Inthe study reported here, macronucleoplasmic transplantation technique was used to test the above hypothesis. When macronucleoplasm of type E3 (mating type E of syngen 3) was injected into a macronucleus of type O12 (mating type O of syngen 12), some recipients changed to type E of the donor syngen but some others changed to type E of the recipient syngen. Thus, syngen specificity of donor macronucleoplasm controlling type E was converted into that of the recipients, even though the latter has no gene that controls type E. When this transformant expressing type E of the recipiexnt syngen was re-injected back into E of the other syngen, the expression of the converted mating type in some way continued in the recipient. This suggests that syngen specificity of gene Mt of the donor was changed to that of the recipients by intersyngenic transplantation of macronucleoplasm. We also obtained results suggesting that the gene dosage ratio of Mt to mt or Mt to MA and MB may be important for syngen specific expression of type E.

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GENETIC ANALYSIS OF GAMMA-RAY MUTAGENESIS IN YEAST. II. ALLELE-SPECIFIC CONTROL OF MUTAGENESIS

Genetics ◽

10.1093/genetics/93.2.375 ◽

1979 ◽

Vol 93 (2) ◽

pp. 375-381 ◽

Cited By ~ 1

Author(s):

Richard H McKee ◽

Christopher W Lawrence

Keyword(s):

Genetic Analysis ◽

Genetic Control ◽

Gamma Ray ◽

Uv Mutagenesis ◽

Gene Functions ◽

Allele Specific ◽

Γ Rays ◽

Specific Control

ABSTRACT We find that partially different sets of gene functions are required for the production of different kinds of mutations induced by 6OCo γ rays in Saccharomyces cereuisiae. This observation is very similar to others made previously with respect to UV mutagenesis (LAWRENCE and CHRISTENSEN 1978a,b, 1979) and confirms the conclusion that such distinctive patterns of genetic control reflect properties of the test alleles and their genetic locations, rather than the kinds of lesions required to revert them. The data also support the model of mutagenic repair outlined in the first paper of this series (MCKEE and LAWRENCE 1979), in which partially different sets of gene functions are required for the production of different kinds of mutations, the formation of mutations at different genetic sites and the induction of mutations by different mutagens.

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On the possible gamma-ray source in Cygnus

Symposium - International Astronomical Union ◽

10.1017/s0074180900101391 ◽

1967 ◽

Vol 31 ◽

pp. 469-471

Author(s):

J. G. Duthie ◽

M. P. Savedoff ◽

R. Cobb

Keyword(s):

Gamma Rays ◽

Gamma Ray ◽

Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

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Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

International Astronomical Union Colloquium ◽

10.1017/s0252921100026208 ◽

1994 ◽

Vol 144 ◽

pp. 635-639

Author(s):

J. Baláž ◽

A. V. Dmitriev ◽

M. A. Kovalevskaya ◽

K. Kudela ◽

S. N. Kuznetsov ◽

...

Keyword(s):

Solar Flare ◽

Energy Range ◽

Gamma Rays ◽

Pulse Shape ◽

Gamma Ray ◽

Pulse Shape Discrimination ◽

Shape Discrimination ◽

Solar Neutron ◽

Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

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