scholarly journals AGE-CORRELATED CHANGES IN EXPRESSION OF MICRONUCLEAR DAMAGE AND REPAIR IN PARAMECIUM TETRAURELIA

Genetics ◽  
1977 ◽  
Vol 87 (2) ◽  
pp. 259-274
Author(s):  
Steven R Rodermel ◽  
Joan Smith-Sonneborn
Keyword(s):  
Life Span ◽  
High Mortality ◽  
Ultraviolet Irradiation ◽  
Paramecium Tetraurelia ◽  
Dark Repair ◽  
Abrupt Increase ◽  
Self Fertilization ◽  
Cross Fertilization

ABSTRACT In Paramecium, age is defined as the number of mitotic divisions which have elapsed since the previous cross-fertilization (conjugation) or self-fertilization (autogamy). As the mitotic interval between fertilizations increases, the percentage of nonviable progeny clones increases. In the current study, resolution of conflicting previous reports on the pattern of increase of death and reduced viability in progeny from aging parent cells is found. Some exautogamous clones exhibit a high mortality at young clonal ages, others show no mortality throughout their life span, but most (73%) show an abrupt increase in the percent death and reduced viability in progeny from cells 50-80 fissions old. Ultraviolet-irradiation-induced micronuclear mutations, repairable by photoreactivation, increased with increased clonal age when monitored by percent death and reduced viability of exautogamous progeny of irradiated cells. Loss of dark repair is considered a contributor to the increased expression of micronuclear mutations with increased clonal age.

Cross-fertilization as a reproductive strategy in a tissue flukesDidymosulcus katsuwonicola(Platyhelmintes: Didymozoidae) inferred by genetic analysis

Parasitology ◽  
2015 ◽  
Vol 142 (11) ◽  
pp. 1422-1429
Author(s):  
IVONA MLADINEO ◽  
MARINA TOMAŠ ◽  
RINO STANIĆ
Keyword(s):  
Life Cycle ◽  
Haplotype Diversity ◽  
Common Mechanism ◽  
High Haplotype Diversity ◽  
Atlantic Bluefin Tuna ◽  
Food Borne ◽  
Self Fertilization ◽  
Successful Fulfillment ◽  
Cross Fertilization ◽  
Host Tissues

SUMMARYMitochondrial DNA locus cytochrome oxidase I was used to asses intraspecific genetic diversity of a didymozoid speciesDidymosulcus katsuwonicola.Adult forms of this species live encapsulated in pairs in the gills of the reared Atlantic bluefin tuna (Thunnus thynnus). The life cycle of this food-borne parasites and its migration in the host tissues after releasing from the digestive tract to the definitive site in the gills are unknown. Our goal was to assess whether two encysted didymozoids share the same haplotype, indicative of a common maternal origin, as well as the extent of cross- in respect to self-fertilization strategy. Intraspecific comparison showed high haplotype diversity, while the presence of two matching haplotypes within a single cyst encompassed only 17% of sampled individuals. This infers that cross-fertilization between paired individuals within the cyst is more common mechanism than self-fertilization. Such hermaphroditic parasite's trait suggests the existence of intricate infection and reproduction mechanisms, presumably as an adaptation for successful fulfillment of their indirect life cycle through dissemination of genetically more diverse and consequently more fit offspring.

Flower drop and fruit set in field beans, Vicia faba L.

1969 ◽  
Vol 72 (1) ◽  
pp. 131-138 ◽  
Author(s):  
A. E. Kambal
Keyword(s):  
Vicia Faba ◽  
Fruit Set ◽  
Local Strain ◽  
Insect Pollination ◽  
Pod Yield ◽  
Vicia Faba L ◽  
Before And After ◽  
Self Fertilization ◽  
Cross Fertilization ◽  
Field Beans

SUMMARYThe percentage of the total buds produced that dropped before reaching the mature pod stage was estimated as 86·7% in Baladi, a local strain of field beans, and 93·7% in Giza 1, a variety introduced from Egypt. The drop was appreciable both before and after fertilization. There were indications that both inadequate insect pollination and inter-ovary competition contributed to the reduction of pod yield.Self pollen was detected on the stigma in the bud stage 2–3 days before the flower was open. Estimates of natural cross-fertilization ranged from 35·8 to 42·1%, indicating that self-pollination did not lead to complete self fertilization. Hand manipulation of the flowers increased pod set in most of the cases but the line 1W did not respond to this treatment and proved to be highly autofertile.

scholarly journals SELF-FERTILIZATION VERSUS CROSS-FERTILIZATION IN THE HERMAPHRODITIC FRESHWATER SNAIL BULINUS GLOBOSUS

Evolution ◽  
1991 ◽  
Vol 45 (5) ◽  
pp. 1136-1146 ◽  
Author(s):  
Philippe Jarne ◽  
Luc Finot ◽  
Bernard Delay ◽  
Louis Thaler
Keyword(s):  
Freshwater Snail ◽  
Self Fertilization ◽  
Bulinus Globosus ◽  
Cross Fertilization

scholarly journals Identification of a gene that shortens clonal life span of Paramecium tetraurelia.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Y Takagi ◽  
K Izumi ◽  
H Kinoshita ◽  
T Yamada ◽  
K Kaji ◽  
...  
Keyword(s):  
Cell Division ◽  
Life Span ◽  
Recessive Mutation ◽  
Supporting Evidence ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Fission Rate ◽  
Cellular Life ◽  
Controlling Mechanism ◽  
Pleiotropic Gene

Abstract We have isolated a Paramecium tetraurelia mutant that divides slowly in daily reisolation cultures and repeats short clonal life spans after successive autogamies. Here we show, using breeding analysis, that a recessive mutation is responsible for the low fission rate and that this low rate is closely related to the short clonal life span. We conclude that a single pleiotropic gene controls these traits and have named it jumyo. In an attempt to further characterize the jumyo mutant, we have revealed that it has a culture life span similar to that of the wild-type cells and that, when mass cultured, it can divide as rapidly as wild-type cells. There was strong evidence that the mutant cells excreted into culture medium some substance that promotes their cell division. These findings may not only present supporting evidence for the hypothesis that the cellular life span is genetically programmed but also give a material basis for the study of the controlling mechanism of cell division in relation to the clonal life span.

DNA Repair and Longevity Assurance in Paramecium tetraurelia

2001 ◽  
Vol 2001 (1) ◽  
Author(s):  
Joan Smith-Sonneborn
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Life Span ◽  
American Association ◽  
The Other ◽  
Repeated Treatment ◽  
Paramecium Tetraurelia ◽  
Uv Treatment ◽  
Life Span Extension ◽  
Cyclobutane Dimers

At given doses and clonal ages, ultraviolet (UV) irradiation-induced DNA damage reduced clonal life-span, but when followed by photoreactivation, extension of clonal life-span was observed. If photoreactivation preceded the UV treatment, no significant beneficial effect was detected. Because studies of others have shown that photoreactivation repair monomerizes the UV-induced cyclobutane dimers in DNA but does not affect the other photoproducts, these result indicate that DNA damage can influence the duration of clonal life-span unless that damage is repaired. Repeated treatment with UV and photoreactivation resulted in significant mean and maximal clonal life-span extension when compared with those of untreated controls, and it is assumed that the rejuvenation effect was due to the correction or prevention of some age damage. Reproduced with permission from Science . Copyright 1979 American Association for the Advancement of Science. Joan Smith-Sonneborn, DNA Repair and Longevity Assurance in Paramecium tetraurelia. Science 203 , 1115-1117 (1979).

Stomatogenesis in Paramecium tetraurelia: genetics and phenotypes of mutants affecting the development of the oral apparatus

1987 ◽  
Vol 65 (9) ◽  
pp. 2177-2187 ◽  
Author(s):  
Lai-Wa Tam ◽  
Stephen F. Ng
Keyword(s):  
Cell Division ◽  
Ultraviolet Irradiation ◽  
Buccal Cavity ◽  
The Other ◽  
Temperature Sensitive ◽  
Paramecium Tetraurelia ◽  
Single Mutant ◽  
Temperature Sensitive Mutants ◽  
Recessive Genes ◽  
Acting In Concert

Seven temperature-sensitive mutants of Paramecium tetraurelia, in which the development of the oral apparatus was affected, were recovered from mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine and ultraviolet irradiation and analysed. Five of them (short-1, buccalless-1, crook-1, monster-1, monster-2) were shown to possess single mutant recessive genes (designated sh1, bu1, cr1, mo1, and mo2, respectively). The other two, short-2 and short-3, were probably of the same mutagenic origin, which involved two linked recessive loci acting in concert. The short mutants are characterized by reduction in the length of the buccal cavity and oral membranelles and disruption of the organization of the membranelles. The crook mutant shows extra curvature and lengthening of the oral membranelles. The buccalless mutant exhibits loss of the buccal cavity, in addition to the absence, shortening, or disruption of the organization of oral membranelles. The monsters develop abnormal oral apparatuses and abnormalities in cell division giving rise to monstrous cells. All of these mutations are pleiotropic in expression. While the genes for short-1 and crook-1 affect stomatogenesis in the asexual and sexual cycles to similar extents, the other five mutants exhibit defects only in asexual stomatogenesis. The developmental interests of these mutants are discussed.

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