A STUDY OF ODD MATING-TYPE DETERMINATION FACTOR BY TRANSFER OF MACRONUCLEAR KARYOPLASM IN PARAMECIUM TETRAURELIA

Genetics ◽  
1984 ◽  
Vol 107 (3) ◽  
pp. 367-373
Author(s):  
Sadaaki Koizumi ◽  
Sumiko Kobayashi
Keyword(s):  
Mating Type ◽  
Direct Evidence ◽  
Unique Feature ◽  
Sensitive Period ◽  
Paramecium Tetraurelia ◽  
Sexual Stage ◽  
Determining Factors ◽  
Determining Factor

ABSTRACT The unique feature of the "B system" of mating-type determination found in Paramecium tetraurelia is the existence of a cytoplasmic difference between odd (O) and even (E) cells created and maintained by the action of their macronuclei. Thus far, the presence of a determining factor that controls the differentiation of the developing zygotic macronucleus for O mating type has not been verified. Results of crosses between cells of differing clonal age and complementary mating type suggest that, for one to two fissions after autogamy, O cells produce some factor that determines the gametic nucleus (micronucleus) as mating type O. Direct evidence for the production of O-determining factor by the young O macronucleus was obtained by transplanting young O macronuclear karyoplasm (a part of the macronucleus) into E cells: 32-35% of E exautogamous clones transformed to O; transformation of E exautogamous clones to O reached as high as 72% by transfer of young O macronuclear karyoplasm from a conjugant, 3-4 hr after mixing. This indicates that O determinants produced by the O macronucleus can also act during the sensitive period of development of the new macronucleus. These O-determining factors may be produced or activated at the sexual stage and then decrease in activity in subsequent fissions after new macronuclear reorganization.

scholarly journals GENETIC ANALYSIS OF MATING TYPE DIFFERENTIATION IN PARAMECIUM TETRAURELIA. II. ROLE OF THE MICRONUCLEI IN MATING-TYPE DETERMINATION

Genetics ◽  
1980 ◽  
Vol 94 (4) ◽  
pp. 951-959
Author(s):  
Y Brygoo ◽  
T M Sonneborn ◽  
A M Keller ◽  
R V Dippell ◽  
M V Schneller
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Cytoplasmic Inheritance ◽  
Mating Types ◽  
Paramecium Tetraurelia ◽  
Macronuclear Development ◽  
Cytoplasmic Factors ◽  
Determining Factors

ABSTRACT The two complementary mating types, 0 and E, of Paramecium tetrauretia are normally inherited cytoplasmically. This property has generally been interpreted to indicate the presence of cytoplasmic factors that determine macronuclear differentiation towards 0 or E . In these macronuclear-cytoplasmic interactions, the micronuclei were held to be unbiased and the determination to be established in the course of macronuclear development. In order to ascertain whether the micronuclei were actually neutral, amicronucleate clones were needed and a method to produce them was developed. In crosses between amicronucleate clones and normal micronucleate clones, we have observed regular deviations from cytoplasmic inheritance: the commonest deviation is that most 0 amicronucleate cells become E when they receive a micronucleus from an E partner. The data can be interpreted by assuming that the micronuclei are predetermined and that the apparent "cytoplasmic" inheritance of the two mating types is due, in E cells, to E-determining factors present in the cytoplasm and in the nucleus; and, in 0 cells, to 0-determining factors present only or mainly in the nucleus.

scholarly journals Evidence for Sexual Reproduction: Identification, Frequency, and Spatial Distribution of Venturia effusa (Pecan Scab) Mating Type Idiomorphs

2018 ◽  
Vol 108 (7) ◽  
pp. 837-846 ◽  
Author(s):  
Carolyn A. Young ◽  
Clive H. Bock ◽  
Nikki D. Charlton ◽  
Chakradhar Mattupalli ◽  
Nick Krom ◽  
...  
Keyword(s):  
United States ◽  
Mating Type ◽  
Spatial Scales ◽  
Southeastern United States ◽  
Draft Genome ◽  
Apple Scab ◽  
Hypothetical Protein ◽  
Sexual Stage ◽  
Pecan Scab ◽  
Conserved Genes

Venturia effusa (syn. Fusicladium effusum), causal agent of pecan scab, is the most prevalent pathogen of pecan (Carya illinoinensis), causing severe yield losses in the southeastern United States. V. effusa is currently known only by its asexual (conidial) stage. However, the degree and distribution of genetic diversity observed within and among populations of V. effusa are typical of a sexually reproducing fungal pathogen, and comparable with other dothideomycetes with a known sexual stage, including the closely related apple scab pathogen, V. inaequalis. Using the mating type (MAT) idiomorphs from V. inaequalis, we identified a single MAT gene, MAT1-1-1, in a draft genome of V. effusa. The MAT1-1-1 locus is flanked by two conserved genes encoding a DNA lyase (APN2) and a hypothetical protein. The MAT locus spanning the flanking genes was amplified and sequenced from a subset of 14 isolates, of which 7 contained MAT1-1-1 and the remaining samples contained MAT1-2-1. A multiplex polymerase chain reaction screen was developed to amplify MAT1-1-1, MAT1-2-1, and a conserved reference gene encoding β-tubulin, and used to screen 784 monoconidial isolates of V. effusa collected from 11 populations of pecan across the southeastern United States. A hierarchical sampling protocol representing region, orchard, and tree allowed for analysis of MAT structure at different spatial scales. Analysis of this collection revealed the frequency of the MAT idiomorphs is in a 1:1 equilibrium of MAT1-1:MAT1-2. The apparent equilibrium of the MAT idiomorphs provides impetus for a renewed effort to search for the sexual stage of V. effusa. [Formula: see text] Copyright © 2018 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals First description of the sexual stage ofVenturia effusa, causal agent of pecan scab

2019 ◽  
Author(s):  
Nikki D. Charlton ◽  
Mihwa Yi ◽  
Clive H. Bock ◽  
Minling Zhang ◽  
Carolyn A. Young
Keyword(s):  
Mating Type ◽  
Culture Media ◽  
Spatial Scales ◽  
Sexual Cycle ◽  
Economic Losses ◽  
Mating Types ◽  
Sexual Stage ◽  
Pecan Scab ◽  
Prevalent Disease ◽  
The Impact

ABSTRACTVenturia effusa, cause of pecan scab, is the most prevalent disease of pecan in the southeastern USA; epidemics of the disease regularly result in economic losses to the pecan industry. Recent characterization of the mating type distribution revealed the frequency of theMATidiomorphs are in equilibrium at various spatial scales, indicative of regular sexual recombination. However, the occurrence of the sexual stage ofV. effusahas never been observed, and the pathogen was previously believed to rely entirely on asexual reproduction. To explore the existence of a sexual cycle, we paired opposite mating types on oatmeal culture media. In initial experiments, cultures were incubated at 24 C for 2 mo for hyphal interactions to occur between mating types and then maintained at 4 C for 4 mo. Immature pseudothecia were initially observed but following exposure to a 12 h photoperiod for 2 weeks at 24 C, asci and ascospores developed. Further experiments explored the effect of time on pseudothecial development with 4 mo at 4 C as the optimal requirement. The results of this study demonstrate the heterothallic nature ofV. effusa.Following experiments investigated progeny from a sexual cross of an albino and a wild-type isolate. Evaluation of isolate pigmentation, mating type, and multilocus genotyping of single ascospore progeny provided evidence that recombination occurred within the sexual crosses. The impact of determining the source of the overwintering ascostroma will aid in management decisions to reduce the primary inoculum in the disease cycle.

scholarly journals Non-Mendelian inheritance of macronuclear mutations is gene specific in Paramecium tetraurelia

1994 ◽  
Vol 14 (4) ◽  
pp. 2479-2484
Author(s):  
J M Scott ◽  
K Mikami ◽  
C L Leeck ◽  
J D Forney
Keyword(s):  
Sexual Reproduction ◽  
Unique Feature ◽  
Protein Gene ◽  
Surface Protein ◽  
Mendelian Inheritance ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Variable Surface ◽  
Type Variable ◽  
Surface Protein Gene

Paramecium tetraurelia contains two types of nuclei, a diploid germinal micronucleus and a large transcriptionally active macronucleus. The macronuclear genome is formed from the micronuclear DNA during sexual reproduction. Previous studies have shown that the processing of the A-type variable surface protein gene during formation of a new macronucleus is dependent on the presence of the A gene in the old macronucleus. It is not clear if this is a general feature that controls the formation of the Paramecium macronuclear genome or a unique feature of the A locus. Using micronuclear transplantation, we have constructed a strain that has a wild-type micronucleus but has macronuclear deletions of the A- and B-type surface protein genes. Neither the A nor the B gene is incorporated into the new macronucleus after sexual reproduction. Macronuclear transformation of this strain with the B gene rescues the B-gene deletion after formation of the next macronucleus but has not effect on the A deletion. Similarly, transformation with the A gene shows gene-specific rescue for A but not B. The effect of the old macronucleus on the processing of the new macronucleus results in a pattern of non-Mendelian inheritance of both macronuclear deletions. Progeny from the wild-type exconjugant are all wild type, and progeny from the A- B- exconjugant are mutant. The features of this A- B- non-Mendelian mutant demonstrate that the regulation of macronuclear DNA processing is gene specific, and our results open the possibility that this type of regulation affects many regions of the Paramecium genome.

scholarly journals Molecular Identification of Mating Type Genes in Asexually Reproducing Fusarium Oxysporum and F. Culmorum

2011 ◽  
Vol 51 (4) ◽  
pp. 405-409 ◽  
Author(s):  
Lidia Irzykowska ◽  
Tomasz Kosiada
Keyword(s):  
Fusarium Oxysporum ◽  
Mating Type ◽  
Molecular Identification ◽  
Dna Sequences ◽  
Control Strategies ◽  
Sexual Stage ◽  
Reproduction Mode ◽  
Successful Control ◽  
Mating Type Genes

Molecular Identification of Mating Type Genes in Asexually ReproducingFusarium OxysporumandF. CulmorumSexually (homothallic and heterothallic) and asexually reproducing species belong to theFusariumgenus. So far, there is no known sexual stage of theF. oxysporumSchlechtend.: Fr. andF. culmorum(W.G. Smith) Sacc. Knowing the reproduction mode is important for the design of successful control strategies, since they are different for clonally and sexually reproducing organisms. In examined sets of asexualF. oxysporumandF. culmorumisolates, the DNA sequences of mating type genes (idiomorphsMAT-1andMAT-2) were identified.MAT-1sequence was detected for 33 and 40% ofF. oxysporumandF. culmorumisolates, respectively. For the remaining isolates a sequence specific forMAT-2was amplified.

scholarly journals Risk-Based Selection in Unemployment Insurance: Evidence and Implications

2021 ◽  
Vol 111 (4) ◽  
pp. 1315-1355
Author(s):  
Camille Landais ◽  
Arash Nekoei ◽  
Peter Nilsson ◽  
David Seim ◽  
Johannes Spinnewijn
Keyword(s):  
Willingness To Pay ◽  
Moral Hazard ◽  
Adverse Selection ◽  
Unemployment Insurance ◽  
Direct Evidence ◽  
Unique Feature ◽  
Ui Design ◽  
Unemployment Risk ◽  
Unemployment Policy

This paper studies whether adverse selection can rationalize a universal mandate for unemployment insurance (UI). Building on a unique feature of the unemployment policy in Sweden, where workers can opt for supplemental UI coverage above a minimum mandate, we provide the first direct evidence for adverse selection in UI and derive its implications for UI design. We find that the unemployment risk is more than twice as high for workers who buy supplemental coverage. Exploiting variation in risk and prices, we show how 25–30 percent of this correlation is driven by risk-based selection, with the remainder driven by moral hazard. Due to the moral hazard and despite the adverse selection we find that mandating the supplemental coverage to individuals with low willingness-to-pay would be suboptimal. We show under which conditions a design leaving choice to workers would dominate a UI system with a single mandate. In this design, using a subsidy for supplemental coverage is optimal and complementary to the use of a minimum mandate. (JEL D82, G22, J65)

scholarly journals Resolution of ST-Segment Depression In Reciprocal Leads As Predictor Mayor Adverse Cardiac Event For ST-Segment Elevation Myocardial Infarction With Fibrinolytic Therapy

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Aldino Satria Adhitya ◽  
Andika Sitepu ◽  
Zulfikri Mukhtar ◽  
Harris Hasan
Keyword(s):  
Myocardial Infarction ◽  
Fibrinolytic Therapy ◽  
Dominant Factor ◽  
Bivariate Analysis ◽  
St Segment Elevation ◽  
St Segment ◽  
Significant Difference ◽  
Determining Factors ◽  
St Elevation ◽  
Determining Factor

Background: ST Elevation Myocardial Infarction (STEMI) may cause Major Cardiovascular Event (MACE). Revascularization needs to be done in all STEMI patients to restore coronary blood flow, hence saving myocardial perfusion. ST Segment Depression (STSD) in reciprocal ECG lead is associated with poor prognosis in STEMI patients receiving fibrinolytic therapy. The main purpose of this study is to evaluate MACE in STEMI patients receiving fibrinolytic therapy using resolution in STSD. Methods: This cohort prospective study with 60 subjects of STEMI patients which are evaluated for MACE (death, heart failure, and rehospitalization) within 30 days after myocardial infarction. Resolution in STSD is defined as resolution ≥ 50% STSD in reciprocal leads within 90 minutes after fibrinolytic therapy.Results: Bivariate analysis showed that Ejection fraction (EF) <40% with OR 8,32 (2,11-32,74), p=0,001; smoking with OR 4,17 (1,05-16,57), p=0,034; Anterior STEMI with OR 3,94 (1,11-13,90), p= 0,027; Creatinine > 1,97 mg/dl with OR 3,69 (1,18-11,55), p= 0,022; complete outpatient medication with OR 5,23 (1,61-17,01), p= 0,004; fragmented QRS with OR 5,23 (1,61-17,01), p= 0,001; resolution in STSD with OR 26,35 (5,16-134, 40), p=<0,001; resolution in ST Segment Elevation with OR 10,5 (2,97-37,24), p=<0,001; are proven to be determining factor for MACE within 30 days. Multivariate analysis showed that among those determining factors for MACE, resolution in STSD on reciprocal leads is evidently the most dominant factor for predicting MACE within 30 days in STEMI patients receiving fibrinolytic therapy [OR 11.47 (1.14-115.10), p=0.038].Conclusion: There is significant difference in MACE within 30 days after myocardial infarction (MI) between patients with and without resolution in STSD. The subjects without resolution in STSD showed higher MACE incidence. Resolution in STSD is evidently an independent predictor for MACE within 30 days after myocardial infarction in STEMI patients.Keywords: Resolution in STSD, MACE, STEMI, Fibrinolytic

scholarly journals Memoirs: Chromosomes, Heredity and Sex: A Review of the Present State of the Evidence with regard to the Material Basis of Herditary Transmission and Sex-Determination

1914 ◽  
Vol s2-59 (236) ◽  
pp. 487-521
Author(s):  
L. DONCASTER
Keyword(s):  
Sex Determination ◽  
Present State ◽  
Direct Evidence ◽  
Sex Chromosome ◽  
The Other ◽  
The Third ◽  
Material Basis ◽  
Preliminary Account ◽  
Determining Factor

In the first section a summary is given of the main lines of argument leading to the conclusion that "Mendelian characters are determined by chromosomes." Some indication is given of the restrictions which must be placed on the meaning of this phrase in respect of the part played by the cytoplasm in heredity. It is concluded that the arguments in its favour, though very strong indirectly, are not supported by sufficient direct evidence to be regarded by themselves as indisputable. In the second section the chief classes of facts are reviewed which suggest a relation between chromosomes and sex-determination, and a preliminary account is given of a new case of an unpaired "sex-chromosome" in the female, in a strain of the moth Abraxas. It is concluded that the arguments for a relation between chromosomes and sex are much stronger than those counecting chromosomes with Mendelian factors. In the third section the facts of sex-limited inheritance are discussed; these are regarded as strongly reinforcing the arguments of the two preceding sections. Lastly, certain difficulties are considered, and it is concluded that sex cannot be determined directly by the presence or absence of a factor which merely determines whether an ovary or a testis shall develop, but that the determining factor causes a certain type of metabolism, which in turn leads to the production of one sex or the other. If such a metabolism is induced by other causes, an individual of one sex may probably arise from gametes which, in the absence of disturbing causes, would have given rise to the other sex.

scholarly journals A Mendelian Mutation Affecting Mating-Type Determination Also Affects Developmental Genomic Rearrangements in Paramecium tetraurelita

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Eric Meyer ◽  
Anne-Marie Keller
Keyword(s):  
Mating Type ◽  
Maternal Inheritance ◽  
Germ Line ◽  
Molecular Model ◽  
Genomic Rearrangements ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Genetic Context ◽  
Pleiotropic Mutation

Abstract In Paramecium tetraurelia, mating type is determined during the differentiation of the somatic macronucleus from a zygotic nucleus genetically competent for both types, O and E. Determination of the developing macronucleus is controlled by the parental macronucleus through an unknown mechanism resulting in the maternal inheritance of mating types. The pleiotropic mutation mtFE affects macronuclear differentiation. Determination for E is constitutive in mutant homozygotes; a number of unrelated mutant characters are also acquired during development. We have examined the possibility that the mutation causes a defect in the developmental rearrangements of the germ-line genome. We show that the excision of an IES (internal eliminated sequence) interrupting the coding sequence of a surface antigen gene is impaired in the mutant, resulting in an alternative macronuclear version of the gene. Once established, the excision defect is indefinitely transmitted across sexual generations in the cytoplasmic lineage, even in a wild-type genetic context. Thus, the processes of mating-type determination and excision of this IES, in addition to their common sensitivity to the mtFE mutation, show a similar maternal inheritance of developmental alternatives in wild-type cells, suggesting a molecular model for mating-type determination.

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