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1
Park, Arum. "Parthenogenesis in Hesiod’s Theogony." Penn State University Press, 2014. http://hdl.handle.net/10150/622192.
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This article examines female asexual reproduction, or parthenogenesis, in Hesiod’s Theogony
and argues that it is a symptom of the unprecedented and unparalleled female presence Hesiod inserts into his cosmos. This presence in turn reflects Hesiod’s incorporation of gender difference and conflict as indispensable both to the creation and, paradoxically, to the stability of the universe. Five of Hesiod’s deities reproduce parthenogenetically: Chaos, Gaea, Night, Strife, and Hera, of whom all but the sexually indeterminate Chaos are female. Hesiod’s male gods have no analogous reproductive ability. The parthenogenetic phases of the early goddesses form much of the fundamental shape and character of the universe, while in the case of Hera, parthenogenesis serves initially as an act of defiance against Zeus but ultimately enforces his reign. Parthenogenesis does not have these functions in either the Near Eastern or other Greek cosmogonic traditions, a difference that reflects Hesiod’s greater emphasis on female participation in his succession myth. Yet Hesiod’s cosmogonic narrative, like others, culminates in the lasting reign of a male god, Zeus. In this context parthenogenesis is a manifestation of female creation, which ultimately reinforces the stability of a male sovereign. The relative prominence of parthenogenesis in the Theogony reflects Hesiod’s emphasis on gender difference and conflict as indispensable to a cosmos in which conflict and concord coexist as equal partners in creation and stability.
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Abbas, Nasser. "Parthenogenesis in plants: putative functions of MCM genes." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964450941.
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Goudie, Frances. "The Evolutionary Genetics of Thelytokous Parthenogenesis in Eusocial Hymenoptera." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13632.
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The phenomenon of thelytoky, the asexual production of diploid female offspring, is being increasingly uncovered among the eusocial Hymenoptera. Thelytoky is associated with a number of fascinating and novel reproductive systems. In this thesis I investigate the evolutionary and genetic consequences of thelytokous parthenogenesis, with particular focus on the Cape honey bee Apis mellifera capensis (hereafter Capensis). In Capensis thelytoky is associated with loss of heterozygosity, which can only be curtailed by ongoing selection against homozygous offspring. This selective cost is one factor that drives the distribution of thelytokous reproduction within the Capensis population, as different castes differ in their ability to endure the costs, and capitalise on the benefits of thelytoky. Considering these costs and benefits in a broader context, I show that the distribution of thelytokous parthenogenesis across the eusocial Hymenoptera can be accounted for by the constraints imposed by caste conflict within an insect colony.
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Lundmark, Magnus. "Evolution of asexuality in insects : Polyploidy, hybridization and geographical parthenogenesis." Doctoral thesis, Umeå : Department of Molecular Biology, Umeå University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-980.
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Kumati, Osama B. Mohamed. "Virus life cycle and the parthenogenesis of malignant catarrhal fever." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38034/.
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Malignant catarrhal fever (MCF) is caused by two closely associated gamma herpes viruses namely alcelaphine herpesvirus 1 (AlHV-1) and ovine herpesvirus 2 (OvHV-2) and characterised with lymphocyte infiltration in non-lymphoid tissues, vasculitis and epithelial damage. The mechanism by which the viruses cause the disease is not fully understood. The hypothesis of this project was that MCF is initiated by aberrant gene expression in endothelium, epithelium and infected T cells of susceptible animals, because they are not the natural hosts for the viruses and the viruses will not have evolved in them. The first goal was to examine whether rabbit epithelium and bovine endothelium can be infected in vitro and in vivo with AlHV-1 using q PCR and, if infected whether viral transcripts could be identified in these tissue cells using q PCR and in situ hybridisation (ISH). The results revealed that endothelium and epithelium can be infected and latent infection can be established in them. This suggests the likelihood of establishing a similar type of infection in vivo. Secondly, the trial to identify latency-associated transcripts using 5-azacitidine treatment on bovine turbinate fibroblast (BT) cells and rabbit large granular lymphocytes (LGLs) was only partially successful. However, pan T antigen was expressed in 5-azacitidine treated but not untreated LGLs cells. This may indicate a function of the drug either directly or through the latency state. Transcriptome analysis in the infected and treated LGLs and BT cells showed that several pathways were affected by 5-aza although a possible latency (low transcript levels) was only seen in the BTs. Transcriptome analysis revealed similar pathways to those described for MCF in the tissues in vivo, and an effect of 5-aza on these. Viral transcripts analysis showed that genes related to productive/lytic cycles were higher than latent ones on day 17 of the in vivo experiment demonstrating that the virus may replicate at this stage of the disease. The attempt to localize the viral transcripts on the rabbit infected tissues using ISH was unsuccessful due to a lack of time.
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Griffin, Clare Louise, and clare griffin@flinders edu au. "A comparison of the ecology and behaviour of parthenogenetic and sexual taxa of the Australian skink, Menetia greyii: implications for coexistence." Flinders University. School of Biological Sciences, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20070202.132116.
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Menetia greyii, a small Australian skink, has recently been determined to be a species complex that consists of both sexual and parthenogenetic taxa (Adams et al. 2003). In total, seven distinct taxa have been identified in the south-central region of Australia. This includes three sexual taxa, three apparent parthenogen lineages, and one lizard of uncertain status
The study population occurs near Bundey Bore station in the semi-arid region of South Australia (approximately 160km north east of Adelaide). At this site, one sexual taxon (SAS) and two all-female parthenogenetic taxa (WP and RP3) were found to occur in sympatry. In a search for ecological differences, I examined spatial, thermal, physiological and morphological niche relationships in the parthenogenetic and sexual forms. Capture rates were used to determine microhabitat and macrohabitat use in the field. The use of different microhabitats and the amount of time spent occupying different exposures (sun vs. shade) were also examined under laboratory conditions. Thermal preferences, physiological performance (sprint speed ability) and daily activity periods were investigated in the laboratory. The study failed to find any major differences among the different taxa that would indicate they are partitioning resources and therefore explain how the sexual and parthenogenetic forms are coexisting. The only difference observed was that the parthenogens expressed superior sprinting ability, running faster than the sexuals over a range of temperatures. In addition, I found that sexual and parthenogenetic females within this population differed very little in their reproductive effort and output, indicating that RP3 and WP parthenogens possess a reproductive advantage over sexual females as a result of not having to produce males (Williams 1975, Maynard-Smith 1978, Bell 1982). In staged interactions between pairs of sexual and parthenogen individuals, the parthenogens were more aggressive and dominated the sexuals. As a result, the parthenogens were able to outcompete the sexuals for food items. This had serious consequences on fitness, with the sexuals losing significantly more weight than the parthenogens. All of these factors would suggest that the parthenogens should eliminate the sexuals at Bundey Bore. Despite this, the parthenogenetic females at Bundey Bore do not outnumber the sexual subpopulation. This raises the question of how the sexuals are persisting. An examination of endoparasites in the scats of parthenogen and sexual M. greyii found that WP parthenogens had significantly higher parasite prevalence than sexuals. Further to this, there is evidence of matings occurring within the study population between sexual males and WP parthenogen females with five tetraploid males being captured. Therefore, WP parthenogens may be suffering from destabilising hybridization. These factors may account for why the parthenogens (or at least the WP parthenogens) have not competitively excluded sexual M. greyii from Bundey Bore. Other possible reasons are discussed in the general discussion in Chapter 8.
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Spence, Jennifer M. "Repetitive DNA in aphids : its nature, chromosomal distribution and evolutionary significance." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298517.
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Law, Jennifer Heather. "The evolution of geographic parthenogenesis and the persistence of asexuality in Timema walking-sticks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61577.pdf.
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Ball, Shelley L. "Evolutionary ecology and population genetics of tychoparthenogenesis in the mayfly, Stenonema femoratum (Ephemeroptera:Heptageniidae) /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9988643.
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Trakalo, Joseph Mark. "The impact of obligate parthenogenesis on concerted evolution of the rDNA IGS in populations of Daphnia pulex." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ56375.pdf.
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McGee, Rob. "Allelism and allele sequence divergence of LOP, the locus of parthenogenesis in the model apomict Hieracium praealtum (Asteraceae)." Thesis, University of Canterbury. School of Biological Sciences, 2013. http://hdl.handle.net/10092/8984.
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Apomixis, or asexual seed development, if introduced into crop species, has the potential to greatly improve global food production. Towards this goal, this study focused on uncovering the genetic mechanisms that control the parthenogenesis step within apomixis whereby fertilisation is avoided. In the model apomict, Hieracium praealtum (Asteraceae), parthenogenesis is controlled by the LOSS OF PARTHENOGENESIS (LOP) locus. Previous research showed that in addition to genomic copies of candidate genes at LOP, the genome has at least three other copies referred to as alternative alleles. The main goal of this study was to investigate four candidate genes, Genes B, X, H and Y, at LOP by generating segregation data of the alternative alleles. BAC clones containing alternative allele sequences were identified and Roche 454 pyrosequenced. These sequences were used to design alternative allele specific primers for genotyping two Hieracium praealtum polyhaploid populations (~ 300 plants).
Four major conclusions were drawn from this study. First, the alternative alleles were in fact acting like alleles to the LOP alleles of Genes B, X and Y. Second, allelic sequence divergence (ASD) of the LOP alleles of Genes B and X relative to the alternative alleles, indicated a recent and separate evolutionary history. Third and, unexpectedly, recombination was detected at the LOP locus, in contrast to other apomixis loci reported in the literature. Furthermore, Gene B was found to be very closely associated with parthenogenesis in the polyhaploid population indicating that it may be essential to parthenogenesis and therefore requires further investigation. On the other hand, the absence of Genes X, Y and H, due to recombination, had no impact upon parthenogenesis. Fourth, the sequence data suggested that the LOP and alternative alleles originated from a shared common allele ancestor. It is hoped that these findings have made a significant contribution towards the future goal of introducing apomixis into crop species.
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Kuhn, Alexandre. "Origin and evolution of social hybridogenesis in Cataglyphis ants: Origine et évolution de l'hybridogenèse sociale chez les fourmis Cataglyphis." Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/287547.
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Hybridization and genetic introgression are significant evolutionary processes playing a keyrole in the adaptation and diversification of species. In desert ants of the genus Cataglyphis,some species have evolved a remarkable reproductive strategy, termed social hybridogenesis,that relies on a perpetual hybridization between two sympatric, yet genetically distinct lineages.The non-reproductive workers systematically result from mating between partners of differentlineages; in contrast, queens and males are both produced asexually by parthenogenesis.Consequently, workers are all interlineage hybrids, whereas reproductives are all pure-lineageindividuals. Although several studies have been carried out on the reproductive strategies ofCataglyphis desert ants, the origin and the mechanisms underlying social hybridogenesis in thegenus remain unclear.In this thesis, I first examined three aspects associated to the persistence of socialhybridogenesis using the ant Cataglyphis mauritanica as a model. (i) I showed that the tightcaste – genotype association stems from a strong genetic influence on female caste fate.However, some degree of phenotypic plasticity was retained in hybrid as well as pure-lineagegenomes, although not expressed in natural conditions. (ii) The genetic survey of a largehybridogenetic population of C. mauritanica reveals that the two lineages occur with equalfrequency. Furthermore, restricted dispersal and parthenogenetic production of queens result ina mosaic of clonal patches. In contrast, males disperse over patches, ensuring successfulinterlineage mating. (iii) To determine whether mating between partners from the same geneticlineage participate to queen production, I simulated genetic data under various rates of sexualvs. asexual queen production. I found that genetic diversity within each lineage fits with theoccurrence a few sex; however, the 100% clonality hypothesis could not be discarded.I then investigated the evolutionary origin of social hybridogenesis in Cataglyphis. Bycharacterizing the reproductive system of 11 Cataglyphis species, five new instances of socialhybridogenesis were discovered. Inferences from phylogenetic analyses, including thesespecies and all Cataglyphis species for which reproductive information was available, indicatedthat this reproductive system independently evolved multiple times in the genus Cataglyphis.Overall, the results of this thesis highlight the singularities of a hybridogenesic systemassociated to queen parthenogenesis, which may have facilitated the repeated evolution ofdependent-lineages in Cataglyphis ants.L’hybridation et l’introgression génétique jouent un rôle majeur dans l’adaptation et ladiversification des espèces. Chez les fourmis du désert du genre Cataglyphis, certaines espècesont évolué une stratégie de reproduction remarquable, appelée hybridogenèse sociale, reposantsur l’hybridation systématique entre deux lignées génétiquement distinctes. Les ouvrières nonreproductricessont issues de l’accouplement entre des partenaires de lignées distinctes ;enrevanche, les reines et les mâles sont produits de façon asexuée par parthénogenèse. Lesouvrières sont donc toutes des hybrides des deux lignées, alors que les individus reproducteurssont de pure-lignées. Bien que plusieurs études aient analysé les stratégies de reproduction desfourmis Cataglyphis, l’origine et le fonctionnement de l’hybridogenèse sociale au sein du genrerestent obscurs.Dans cette thèse, trois aspects associés au maintien de ce système ont premièrement étéétudiés en prenant la fourmi Cataglyphis mauritanica comme modèle. (i) La forte associationentre génotype et caste des femelles est lié à une forte influence génétique sur le déterminismede la caste. Néanmoins, une certaine plasticité phénotypique est maintenue dans les génomeshybrides et pure-lignée mais elle ne s’exprime pas en conditions naturelles. (ii) L’analysegénétique d’une population hybridogène de C. mauritanica montre que les deux lignées sontéquifréquentes. De plus, une dispersion limitée des reines ainsi que leur production parparthénogenèse mènent à la formation d’une mosaïque de patches clonaux. A l’inverse, lesmâles dispersent d’un patch à l’autre assurant les accouplements interlignées. (iii) Afin dedéterminer si les accouplements intralignées participent à la production des reines, des donnéesgénétiques ont été simulées sous différents taux de reproduction sexuée et asexuée. Les résultatsmontrent que la diversité génétique au sein de chaque lignée correspond à une faible fréquencede reproduction sexuée, bien que qu’un scénario avec 100% de clonalité ne puisse être écarté.Ensuite, l’origine évolutive de l’hybridogenèse sociale chez les Cataglyphis a étéanalysée. L’étude des systèmes reproducteurs de 11 espèces de Cataglyphis a permis ladécouverte de 5 nouveaux systèmes hybridogènes. Des analyses phylogénétiques, basées surces espèces et sur toutes les espèces de Cataglyphis pour lesquels le système reproducteur a étéprécédemment étudié, indiquent que ce système reproducteur aurait évolué plusieurs foisindépendamment au sein du genre Cataglyphis.En conclusion, les résultats de cette thèse soulignent les singularités d’un systèmehybridogène associé à la parthénogénèse des reines, qui a pu faciliter l’évolution répétée delignées dépendantes chez les fourmis Cataglyphis.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Hanson, Sara Jeanette. "The molecular evolution of reproduction in animals: insights from sexual and asexual rotifers." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1618.
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Sex and meiosis are ubiquitous in eukaryotes as the primary mode of reproduction. This suggests that despite the theoretical energetic advantages of asexual reproduction, organisms capable of sexual reproduction are at a much greater long-term evolutionary advantage. Rotifers, a group of microinvertebrates, offer unique opportunities to examine the evolution of sex due to their extensive proliferation, successful adaptation to a wide variety of ecological niches, and the diversity of reproductive modes represented in the group. The cyclically parthenogenetic monogonont rotifers have overcome constraints on the loss of sexual reproduction in order to frequently transition between sexual and asexual generations, making them a powerful system with which to address the maintenance of sex in animals. Obligately asexual bdelloid rotifers appear to have thrived without sex for tens of millions of years, a period of time much longer than expected given the hypothesized advantages of sexual reproduction. However, the molecular nature of sex and parthenogenesis is poorly understood in any rotifer species.
To expand our knowledge of the molecular mechanisms of monogonont reproduction, we sequenced genomes of two distantly related species, Brachionus calyciflorus and Brachionus manjavacas and identified over 80 homologs for genes involved in meiotic processes. Several of these genes have undergone duplication events specific to the monogonont lineage, including genes with known roles in regulation of cell cycle transitions during meiosis. In addition, global gene expression patterns were determined using obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of B. calyciflorus. Quantitative comparison of expression between these strains revealed differentially expressed genes specific to sexual and asexual reproduction in this species, including genes related to dormancy/resting egg formation, meiosis, and hormone signaling pathways that are thought to be involved in the induction of sexual reproduction in monogononts. Finally, we analyzed gene expression in bdelloid rotifers for evidence of sexual reproduction or the utilization of meiotic genes under conditions inducing high levels of recombination.
Through this work, we have established molecular markers for sexuality and asexuality in monogonont rotifers, and used these markers to evaluate reproduction in bdelloids. The data generated specifically allows for more informed analyses of the evolution of cyclical parthenogenesis and rotifer reproduction. Furthermore, this work extends the use of monogononts as a model system for addressing broader questions regarding the evolution of sexual reproduction.
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Rey, Olivier. "Systèmes de reproduction et scénarios d’invasion chez la petite fourmi de feu, Wasmannia auropunctata." Electronic Thesis or Diss., Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0046.
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Cette thèse vise à améliorer notre connaissance des processus évolutifs et écologiques liés aux invasions biologiques au travers de l'étude de populations envahissantes et non envahissantes de la petite fourmi de feu, Wasmannia auropunctata. Cette espèce présente un polymorphisme du système de reproduction original. Dans les populations ancestrales, les reines et les mâles se reproduisent selon le mode de reproduction sexué classique des hyménoptères (haplo-diploïde). Dans d'autres populations, les reines sont parthénogénétiques et les mâles sont produits de manière clonale via les œufs pondus par la reine. Ces reines et ces mâles produisent néanmoins des ouvrières stériles sexuellement. Ce mode de reproduction clonal semble associé indirectement au succès d'invasion des populations. Dans un premier temps nous avons identifié les mécanismes sous-jacents au système de reproduction des populations clonales. Nos résultats montrent que les reines utilisent la parthénogenèse automictique associée à une réduction du taux de recombinaison pour la production de reines, l'androgenèse pour la production des mâles et la reproduction sexuée pour la production d'ouvrières stériles. La fixation des génomes parentaux dans les descendances successives permet la reproduction entre individus d'une même cohorte en évitant la dépression de consanguinité dans la descendance ouvrière. Nous avons ensuite montré que le changement de système de reproduction de la sexualité vers la clonalité est associé à un changement adaptatif permettant aux ouvrières des populations clonales de mieux tolérer les températures stressantes caractéristiques des localités envahies, comparativement aux ouvrières des populations sexuées ancestrales. Enfin, l'utilisation d'une approche multidisciplinaire couplant des modèles de distribution d'espèces, des analyses de génétique des populations et des expériences en laboratoire, nous a permis de montrer que les changements évolutifs clefs associés au succès d'invasion des populations, ont lieu dans des habitats marginaux de l'aire native, avant la dispersion vers des localités distantes caractérisées par des conditions environnementales similairesThe main goal of this thesis is to provide new insights on the evolutionary processes associated to biological invasions through the study of invasive and non-invasive populations of the little fire ant, W. auropunctata. This species is characterised by an eccentric breeding system polymorphism. In ancestral populations, queens and males reproduce following the classical sexual reproduction system of hymenopteran species (haplo-diploid). In some other populations, queens reproduce by parthenogenesis and the males are reproduced clonally through queens' eggs. These clonal queens and males nevertheless produce sterile workers sexually. Interestingly this clonal reproduction seems indirectly associated with the invasive success of populations. In this study, we first identified the mechanisms underlying the breeding system of clonal populations. Our results indicate that queens use automictic parthenogenesis associated with a drastic reduction of meiotic recombination rate, androgenesis and sexual reproduction for the production of queens, males, and sterile workers respectively. The fixation of parental genomes in the successive generations allows individuals from the same cohort to reproduce together avoiding inbreeding depression in their worker offspring. We also found that the change of breeding system from sexuality to clonality is associated with an adaptive change that allow workers from clonal populations to better tolerate the stressing temperatures of invaded areas better than workers from ancestral sexual populations. Finally, we used a developed mutlidisciplinary approach combining niche modelling, genetic analyses and laboratory experiments, and found that the above evolutionary changes occur within the native range in marginal habitats prior to long-distance dispersal events into localities that display similar environmental conditions
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Taylor, Alison Sandra. "Human parthenogenesis : an investigation to determine whether human parthenogentic embryos can be used as an alternative model for embryo research." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244020.
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Vandervoort, Carla Louise. "Geographic parthenogenesis: A case study of sexual and apomictic Erigeron strigosus Muhl. ex Willd. (prairie fleabane) in the southeastern United States." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433499.
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Porciuncula, Patrícia Marafon. "Ativação partenogenética de oócitos bovinos jovens com ionomicina e 6-dimetilaminopurina associado ou não ao estrôncio." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-14112007-155048/.
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Tendo em vista a possibilidade da associação de agentes ativadores aliada à influência da idade do oócito no desenvolvimento embrionário, a proposta deste trabalho foi estudar a relação entre o envelhecimento do oócito e a ativação partenogenética. Para tal, oócitos bovinos foram maturados in vitro por um período de 22 h (jovens) e 28 h (envelhecidos). Em seguida, os dois grupos de oócitos foram ativados com os tratamentos: ID3: ionomicina (5 µM por 5 min) + 6DMAP (2 mM por 3 h de incubação); ID6: ionomicina (5 µM por 5 min) + 6DMAP (2 mM por 6 h de incubação); IDS: ionomicina + associação 6DMAP (2 mM) e estrôncio (20 mM; SrCl2) por 6 h e IDSS: ionomicina + (6DMAP+Sr) nas primeiras 3 h, seguido de lavagem e incubação com estrôncio (Sr2+) isoladamente por mais 3 h de incubação. O grupo controle foi cultivado na ausência de qualquer agente ativador (ativação espontânea). Após a ativação os oócitos foram avaliados quanto a: 1) taxa de ativação (formação de pronúcleo às 12 hpa); 2) atividade do fator promotor de maturação (MPF) e proteína cinase ativada por mitógeno (MAPK) nos intervalos de 5 min, 3 h, 6 h e 10 h; 3) desenvolvimento embrionário (taxa de clivagem às 48 h, dia 7 e 9 taxas de blastocisto e eclosão); 4) qualidade dos embriões (dia 9 pelo número total de células, apoptose e expressão de interferon-t). Em geral, oócitos jovens apresentaram menor taxa de ativação e maior atividade de MPF e MAPK em relação aos envelhecidos. No entanto, a incubação dos oócitos em 6DMAP por 6 h permitiu taxas semelhantes aos envelhecidos com pequeno prejuízo em número de células, sem efeitos em outros critérios de qualidade do embrião. Os dados sugerem possíveis aplicações destes resultados de maneira a contribuir para a TN com flexibilidade de horários e produção de embriões de boa qualidade.Considering the possibility of the combination of different activating agents associated to the influence of oocyte ageing on embryo development, the purpose of this work to study the relationship between oocyte ageing and parthenogenetic activation. Bovine oocytes were in vitro maturated for 22 (young) and 28 h (aged). Next, both groups of oocytes were activated using the following treatments: ID3: ionomycin (5 µM for 5 min) + 6DMAP (2 mM for 3 h); ID6: ionomycin (5 µM for 5 min) + 6DMAP (2 mM for 6 h); IDS: ionomicyn + 6DMAP (2 mM) and strontium (20 mM; SrCl2) for 6 h and IDSS: ionomicyn + (6DMAP+Sr2+) for the first 3h, followed by incubation with Sr2+ alone for another 3 h. The control group was cultured in the absence of any activating agents (spontaneous activation). After activation, the oocytes were evaluated for: 1) activation rate (pronuclei formation at 12 hpa); 2) activity of maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK) at 5 min, 3 h, 6 h and 10 hpa; 3) embryo development (cleavage rate at 48 h and blastocyst and hatching rates on days 7 and 9); 4) embryo quality (day 9 regarding total cell numbers, apoptosis and interferon-t expression). In general, young oocytes showed lower activation rates and higher MPF and MAPK activity when compared with aged oocytes. However, incubation of the oocytes with 6DMAP for 6 h allowed development rates similar to aged oocytes with a small decrease in total cell number, but without effects on other criteria of embryo quality. The data suggest a possible application of these results in such a way to contribute for timing flexibilization in NT experiments and production of good quality embryos.
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Miyauchi, Tochimara Aparecida. "Aspectos biológicos do desenvolvimento pré- implantacional de embriões bovinos partenogenéticos ou fecundados in vitro." Universidade Jose do Rosario Vellano, 2012. http://tede2.unifenas.br:8080/jspui/handle/jspui/140.
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Parthenogenesis has been described as an alternative method to produce embryos for studies with embryonic cells, particularly in humans which have a restriction of fertilized embryos. Procedures used in parthenogenesis are also required to produce embryos by somatic cell nuclear transfer in domestic species. However, many biological, cellular and molecular aspects of parthenogenetic embryos are still unknown. This study aimed to compare the kinetics of development, apoptosis rate and gene expression of stress and celular metabolism in bovine parthenogenetic embryos and embryos fertilized in vitro. Oocytes (n = 1541) obtained from slaughterhouse ovaries were matured in vitro and submitted to parthenogenetic activation (4.62 µM ionomycin for 5 min followed by 2 mM 6-DMAP for 4 h) or in vitro fertilization (2 x 106 sperm/mL for 20h with semen from a single departure). 72h postactivation/fertilization (hpaf), embryos (8-cell) were frozen for subsequent analysis of gene expression and another part has been separated into groups of high or low potential of development: Part ≥ 8 - parthenogenetic embryos with 8 or more cells (high development potential); Part < 8 - embryos less than 8 cells (low development potential); ≥ 8 IVF - in vitro fertilized embryos with 8 or more cells; and IVF < 8 - embryos with less than 8 cells. Embryos were cultured in CR2aa medium with 2.5% BFS in 5% CO2, 5% O2, 90% N2 at 38.5° C and were evaluated rates of blastocyst 168hpaf (D7) and 196hpaf (D8). 8-cell embryos obtained after 72hpfa were analyzed for gene expression. D8 blastocysts were fixed and subsequently apoptotic index was analyzed by TUNEL. Data were compared by analysis of variance and means by Student Newman Keuls test. Gene expression was evaluated by REST® software. Values are shown as mean ± standard error. Embryos with 8 or more cells produced higher (P < 0.01) blastocysts rates in D7 and D8 compared to embryos with less than eight cells, showing its greatest development potential, regardless if they were parthenogenetic or fertilized. Embryos of Part ≥ 8 group had higher (P <0.05) blastocyst rate in D7 (63.6 ± 3.4%) than IVF ≥ 8 (45.3 ± 8.9%), but at D8 rate was similar (56.7 ± 3.0% and 44.2 ± 8.9% for Part ≥ 8 and IVF ≥ 8, respectively; P <0.05). There was no difference (P < 0.05) on blastocyst rates at D7 and D8 between embryos with less than 8 cells derived from parthenogenesis or fertilization. There was no difference in total cell number (92.0 ± 3.4, 102.30 ± 4.8), apoptotic cells (10.8 ± 1.22, 9.5 ± 1.07) and apoptotic index (11.4 ± 1.27, 9.8 ± 1.8) for parthenogenetic and IVF blastocysts, respectively. In 8-cell embryos analyzed, there was a subexpression of genes DNAJB1, HSPA1L, HSF1 and GLUT1 for Part in relation to FIV, while HSF2 was overexpressed in Part compared to FIV. In conclusion, bovine parthenogenetic embryos differ to embryos fertilized in vitro in hability of preimplantation development in vitro and gene expression, which may limit the use of parthenogenesis in studies of embryonic development.
A partenogênese tem sido descrita como um método alternativo para produzir embriões para estudos com células embrionárias, principalmente em humanos para os quais existe a restrição do uso de embriões fecundados. Procedimentos utilizados na partenogênese são também necessários para se produzir embriões por transferência nuclear com células somáticas nas espécies domésticas. Contudo, muitos aspectos biológicos, celulares e moleculares dos embriões partenogenéticos ainda são desconhecidos. Este estudo objetivou comparar a cinética do desenvolvimento, índice de apoptose e expressão de genes de estresse e metabolismo celular em embriões bovinos partenogenéticos e embriões fecundados in vitro. Oócitos (n=1541) obtidos de ovários de matadouro foram maturados in vitro e submetidos à ativação partenogenética (4,62 µM ionomicina por 5 min seguido de 2 mM 6-DMAP por 4h) ou fecundação in vitro (2 x 106 espermatozoides/ml por 20h, com sêmen de uma única partida). Com 72h pós-ativação/fecundação (hpaf) parte dos embriões (8 células) foram congelados para posterior análise da expressão gênica e outra parte foi separada em grupos de alto ou baixo potencial de desenvolvimento: Part≥8 - embriões partenogenéticos com 8 ou mais células (alto potencial de desenvolvimento); Part<8 - embriões com menos de 8 células (baixo potencial de desenvolvimento); FIV≥8 - embriões fecundados in vitro com 8 ou mais células; e FIV<8: embriões com menos de 8 células. Os embriões foram cultivados em meio CR2aa com 2,5% SFB em 5%CO2, 5%O2, 90% N2 a 38,5ºC e avaliadas as taxas de blastocistos com 168hpaf (D7) e 196hpaf (D8). Embriões com 8 células obtidos após 72hpfa foram analisados quanto à expressão gênica. Blastocistos em D8 foram fixados e posteriormente foram avaliados pela técnica de TUNEL o índice apoptótico. Os dados foram comparados por análise de variância e as médias por teste de Student Newman Keuls. A expressão gênica foi avaliada pelo software REST®. Os valores são mostrados como média±erro padrão. Embriões com 8 ou mais células produziram maiores (P<0,01) taxas de blastocistos no D7 e D8 do que os embriões com menos de oitos células mostrando seu maior potencial de desenvolvimento, independentemente se foram partenogenéticos ou fecundados. Embriões do grupo Part≥8 apresentaram maior (P<0,05) taxa de blastocistos no D7 (63,6±3,4%) que os FIV≥8 (45,3±8,9%), porém a taxa no D8 foi semelhante (56,7±3,0% e 44,2±8,9% para Part≥8 e FIV≥8, respectivamente; (P<0,05). Não houve diferença (P<0,05) quanto às taxas de blastocistos no D7 e D8 entre embriões com menos de 8 células oriundos da partenogênese ou fecundação. Não houve diferença quanto ao número total de células (92,0±3,4; 102,30±4,8), células apoptóticas (10,8±1,22; 9,5±1,07) e índice apoptótico (11,4±1,27; 9,8±1,8) nos blastocistos partenogenéticos e FIV, respectivamente. Nos embriões com 8 células analisados, houve subexpressão dos genes DNAJB1, HSPA1L, HSF1, GLUT1 nos Part em relação aos FIV, enquanto o HSF2 esteve sobrexpresso nos Part quando comparado aos FIV. Conclui-se que embriões partenogenéticos bovinos possuem diferenças se comparados aos embriões fecundados in vitro quanto à capacidade de desenvolvimento pré-implantacional in vitro e expressão gênica, o que pode limitar o uso da partenogênese em estudos sobre desenvolvimento embrionário.
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Pearcy, Morgan. "Stratégies reproductrices chez la fourmi Cataglyphis cursor." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210909.
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La sélection de la parentèle est le concept actuellement le plus fréquemment avancé pour justifier l’évolution et le maintien d'une caste ouvrière stérile chez les Hyménoptères sociaux. La fourmi méditerranéenne Cataglyphis cursor possède plusieurs traits biologiques qui font de cette espèce un modèle particulièrement intéressant pour tester les prédictions de la théorie de la sélection de la parentèle, le plus important d'entre eux étant la capacité des ouvrières, qui ne s'accouplent jamais, à produire une descendance mâle (haploïde) par parthénogenèse arrhénotoque, ou femelle (diploïde) par parthénogenèse thélytoque. Nos analyses génétiques, basées sur des marqueurs microsatellites développés au préalable pour cette espèce, ont révélé que les reines utilisent la reproduction sexuée et asexuée respectivement pour la production de la caste ouvrière et reproductrice. L'analyse du pedigree des reproductrices issues de la reproduction asexuée nous a permis d'identifier le mécanisme cytologique de la parthénogenèse thélytoque et d'estimer la proportion de reines issues de la reproduction des ouvrières au sein de la population. De plus, bien que les reines soient capables de produire une descendance diploïde (femelle) par parthénogenèse thélytoque, elles ont conservé la reproduction sexuée pour la caste ouvrière et s'accouplent avec plusieurs mâles. Ceci indique que la reproduction sexuée a une fonction importante au niveau de la colonie, et nous avons testé certaines des hypothèses avancées pour justifier l'évolution de la polyandrie. Finalement, nous avons étudié l'impact des stratégies de dispersion de cette espèce sur le sex-ratio de la descendance sexuée. Ces résultats confirment l'intérêt que représente l'étude des stratégies reproductrices chez les Hyménoptères sociaux pour tester les prédiction de diverses théories en biologie évolutives et ouvrent également de nouvelles perspectives de recherche, tant chez C. cursor que chez d'autres espèces appartenant au genre Cataglyphis.Kin selection is, to date, the most widely accepted theory to justify the evolution of a sterile worker caste among social Hymenoptera. The Mediterranean ant Cataglyphis cursor represents an interesting biological model for several reasons, the most important of them being the ability for unmated workers to produce haploid (male) offspring, through arrhenotokous parthenogenesis, and diploid (female) offspring, through thelytokous parthenogenesis. Our genetic analyses, based on microsatellite loci developed for this purpose, revealed that queens selectively use sexual and asexual reproduction to produce workers and sexuals, respectively. Pedigree analyses allowed us to identify the cytological mechanism involved in thelytokous parthenogenesis and to estimate the proportion of worker-produced queens in the study population. Although C. cursor queens do not require mating to produce diploid offspring, they have retained sexual reproduction and mate multiply with up to 8 males. This suggests that sexual reproduction has important benefits for colony function, and we tested several hypotheses accounting for the evolution of polyandry. Eventually, we studied the effect of dispersal strategies on sex-ratio of the sexual brood. These results confirm the interest of investigating the reproductive strategies of social Hymenoptera to test the predictions of diverse theories in the field of evolutionary biology, and open new research perspectives in C. cursor and other ants of the Cataglyphis genera.
Doctorat en Sciences
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Rascado, Tatiana da Silva [UNESP]. "Produção de embriões por fecundação in vitro e ativação partenogenética visando o isolamento de células tronco embrionárias felinas." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/94582.
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rascado_ts_me_botfmvz.pdf: 550386 bytes, checksum: 2b1967d2846b363e04547e6d5a1ff2fb (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo deste estudo foi aprimorar os protocolos de produção in vitro de embriões e de ativação partenogenética visando o isolamento e o cultivo de células tronco embrionárias felinas. Os CCOs-I foram obtidos a partir de ovários de gatas adultas e maturados in vitro. No experimento I, os CCOS foram fecundados e os embriões cultivados nos meios SOFaa e FOC. Foram comparadas as taxas de clivagem e a produção de blastocistos. A análise estatística foi realizada por meio da análise de variância e a viabilidade embrionária foi avaliada por sondas fluorescentes (Hoechst e iodeto de propídio). Não houve diferenças significativas entre os meios de cultivo, os quais apresentaram taxas de clivagem de 50,5±9,47 e 63,75±5,9 (P>0,05) e de produção de blastocistos em relação ao total de oócitos fecundados de 18±5,07 e 33,2±3,71 (P>0,05) para FOC e SOF respectivamente. No experimento II, os CCOs maturos foram submetidos a três diferentes protocolos de ativação partenogenética: 1-ionomicina associada ao cicloheximide; 2-ionomicina associada ao roscovitine e 3-ionomicina associada ao estrôncio, os quais foram comparados entre si e ao controle quanto às taxas de ativação, clivagem e desenvolvimento embrionário, sendo cultivados em SOFaa por 72 horas após a ativação. Para tais avaliações, oócitos e embriões foram corados com Hoechst 33342 e examinados em microscópio invertido. Como análise estatística foi utilizado o teste qui-quadrado. Não houve diferença significativa entre os tratamentos quanto à taxa de oócitos ativados (69,9%, 76,6% e 64,6%, para tratamento 1, 2 e 3 respectivamente) (P>0,05) nem quanto às taxas de clivagem (46,6%, 46,73% e 32,32%, para tratamento 1, 2 e 3 respectivamente) (P>0,05), mas sim entre estes e o controle (36% e 12%, respectivamente, para taxa de oócitos ativados e taxas de clivagem) (P<0,05). Quanto ao desenvolvimento...
The objective of this study was to improve the existent protocols for in vitro embryos production and parthenogenetic activation in cats, aiming the isolation and culture of feline embryonic stem cells. COCs-I were collected from adult queens´s ovaries and matured in vitro. In the experiment I, COCs were fertilized and embryos cultured in two culture media, SOFaa and FOC. In both media the cleavage rate and blastocysts production were compared. Fluorescents probes (Hoechst and propidium iodide) were utilized to estimate embryo viability. The statistical analysis was realized through the ANOVA. No statistical difference was observed between culture media. The cleavage rates considering the total number of fertilized oocytes were 50.5±9.47 and 63.75±5.9 (P>0.05) for FOC and SOF medium respectively. Similarly, the blastocysts production rates were 18±5.07 and 33.2±3.71 (P>0.05) for FOC and SOF, respectively. In experiment II matured COCs were submitted to three parthenogenetic activation protocols: 1- ionomycin associated to cycloheximide; 2 – ionomycin associated to roscovitine; 3 – ionomycin associated to strontium. The treatments were compared among themselves and among them and the control concerning chromatin decondensation, cleavage and embryo development rates. The parthenogenetic embryos were then cultured in SOFaa during 72 hours. To estimate chromatin status and number of nuclei, oocytes and embryos were stained with Hoechst 33342 and examined under an inverted fluorescent microscope. As statistical analyses chi-square test was utilized. No statistical difference was observed among treatments concerning activated oocytes rates (69.9%, 76.6% e 64.6%, respectively, for treatment 1, 2 and 3) (P>0.05) neither cleavage rates (46.6%, 46.73% e 32.32%, respectively, for treatment 1, treatment 1, 2, 3) (P>0.05). However, statistical difference was observed among treatments and... (Complete abstract click electronic access below)
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Mathias, Frank Furlong Jr. "A Plio-Pleistocene Record of Lacustrine Ostracodes from Butte Valley, California: Faunal Responses to Tectonic and Climatic Change." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1404725598.
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Smith, Hilary April. "Evolution of Reproduction and Stress Tolerance in Brachionid Rotifers." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/52145.
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Stress can be a driving force for new evolutionary changes leading to local adaptation, or may be responded to with pre-existing, ancestral tolerance mechanisms. Using brachionid rotifers (microzooplankton) as a study system, I demonstrate roles of both conserved physiological mechanisms (heat shock protein induction) and rapid evolution of traits in response to ecologically relevant stressors such as temperature and hydroperiod. Rapid evolution of higher levels of sex and dormancy in cultures mimicking temporary waters represents an eco-evolutionary dynamic, with trait evolution feeding back into effects on ecology (i.e., reduced population growth). I also reveal that prolonged culture in a benign laboratory environment leads to evolution of increased lifespan and fecundity, perhaps due to reduction of extrinsic mortality factors. Potential mechanisms (e.g., hormonal signals) are suggested that may control evolvability of facets of the stress response. Due to prior studies suggesting a role of progesterone signaling in rotifer sex and dormancy, the membrane associated progesterone receptor is assayed as a candidate gene that could show positive selection indicating rapid divergence. Despite some sequence variation that may contribute to functional differences among species, results indicate this hormone receptor is under purifying selection. Detailed analyses of multiple stress responses and their evolution as performed here will be imperative to understanding current patterns of local adaptation and trait-environment correlations. Such research also is key to predicting persistence of species upon introduction to novel habitats and exposure to new stressors (e.g., warming due to climate change). Perhaps one of the most intriguing results of this dissertation is the rapid, adaptive change in levels of sex and dormancy in a metazoan through new mutations or re-arrangements of the genetic material. This suggests species may be able to rapidly evolve tolerance of new stressors, even if standing genetic variation does not currently encompass the suite of alleles necessary for survival.
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Bem, Tiago Henrique Camara De. "Efeito da pré-maturação sobre o desenvolvimento embrionário de oócitos submetidos à ativação partenogenética e transferência de núcleo." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-08092009-114443/.
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As taxas de produção embrionária tanto da FIV (30-40%) como da TN (23%) ainda estão aquém do esperado. Desta forma, a pré-maturação com inibidores do ciclo celular é uma das alternativas que vem sendo estudada para aumentar a competência dos oócitos utilizados na PIV, na tentativa de otimizar o sucesso das biotécnicas. Sabe-se que neurotrofinas desempenham funções no sistema reprodutor. O BDNF é um exemplo de neurotrofina que parece estar relacionada com a maturação dos oócitos. Desta forma, o objetivo deste trabalho foi de aperfeiçoar a pré-maturação e a maturação in vitro de oócitos bovinos submetidos posteriormente à ativação partenogenética, visando seu uso na biotécnica de transferência de núcleo. Oócitos bovinos foram submetidos à maturação na presença (MIV/BD) ou ausência (MIV) de BDNF ou pré-maturados com BLI e suplementados (BL/BD) ou não (BL) com a neurotrofina. Posteriormente foram avaliados quanto à taxa de maturação (metáfase II), ativação (formação de prónúcleo) e desenvolvimento embrionário (produção e qualidade dos blastocistos). Não houve diferença (P>0,05) entre taxas de MII após a maturação com ou sem BDNF. Porém, o grupo pré-maturado e suplementado (BL/BD n=73; 91,2%) apresentou maior taxa de MII (P<0,05) em relação ao grupo não suplementado (BL n=66; 76,7%). Oócitos maturados nas mesmas condições foram ativados quimicamente para análise do desenvolvimento embrionário. Os grupos MIV/BD (n=30; 71,4%) e MIV (n=41; 91.1%) apresentaram diferença (P<0,05) em relação à taxa de ativação. Porém, não foi observada diferença quanto aos outros parâmetros do desenvolvimento. Quando os oócitos foram pré-maturados a taxa de clivagem do grupo suplementado (BL/BD: n=227; 65,2%) foi superior (P<0,05) ao grupo não suplementado (BL: n=187; 57,7%), mas não foram observadas diferenças (P>0,05) para os outros parâmetros de desenvolvimento. A qualidade dos embriões ativados também não foi afetada pelos tratamentos. Os grupos submetidos à TN (MIV e BL/BD) apresentaram diferenças (P<0,05) para extrusão do 1°CP (n=639; 63,5% e n=693; 69,5%, respectivamente) e para taxa de fusão (n=345; 72,9% e n=397; 79,2%, respectivamente) não havendo diferença para nenhum outro parâmetro avaliado. A qualidade dos embriões clonados também foi avaliada e não foi observada diferença. Após a transferência dos embriões dos grupos MIV (n=28) e BL/BD (n=26) para as receptoras, os grupos foram capazes de produzir gestação avançadas (10,7 e 11,5%, respectivamente) de forma similar (P>0,05). Com base nestes resultados podemos concluir que a suplementação, tanto da maturação como a pré-maturação não causa prejuízo no posterior desenvolvimento embrionário. Ainda, embriões clonados produzidos a partir de oócitos bloqueados são capazes de estabelecer gestações avançadas em bovinos.Embryo production rates obtained from both IVF (30-40%) and NT (23%) are still below the expected values. Therefore, oocyte pre-maturation using cell cycle inhibitors is one of the alternatives which has been studied to increase the competence of oocytes used for IVP, as an attempt to optimize the success rates of these biotechniques. Neurotrophins are known to play several roles in the reproductive system. BDNF is an example of a neurotrophin that seems to be related to oocyte maturation. Therefore, the objective of this study was to improve techniques of pre-maturation and maturation of bovine oocytes submitted to parthenogenetic activation, aiming for its use on cloning by nuclear transfer. Bovine oocytes were submitted to maturation either in presence (IVM/BD) or absence (IVM) of BDNF or pre-matured with BLI and supplemented (BL/BD) or not (BL) with the neurotrophin. Groups were evaluated for maturation rates (metaphase II), activation (pro-nucleus formation) and embryo development (blastocyst formation rate and quality). There was no difference (P>0.05) in MII rate after the maturation with or without BDNF. However, pre-maturation in the supplemented group (BL/BD, n=73; 91.2%) resulted in higher MII rate (P<0.05) when compared with the nonsupplemented group (BL, n=66; 76.7%). Oocytes which were matured under the same conditions were also activated chemically for embryonic development analysis. Activation rates were different (P<0.05) from IVM/BD groups (n=30; 71.4%) and IVM (n=41; 91.1%). However, no difference were observed for development parameters. When the oocytes were prematured, cleavage rates in the supplemented group were superior (P<0.05) than non supplemented group (BL/BD: n=227; 65.2%) and (BL: n=187; 57.7%), but no difference was observed for other developmental parameters. Embryo quality was also evaluated and no difference was observed between treatments. Groups submitted to NT (IVM and BL/BD) differed regarding (P<0.05) the 1stPB extrusion (n=639; 63.5% and n=693; 69.5%, respectively) and fusion rate (n=345; 72.9% and n=397; 79.2%, respectively), but did not present differences for other evaluated parameters. Embryo quality was evaluated again and no differences were observed. After the embryos were transferred to recipient cows, groups IVM (n=3; 10.7%) and BL/BD (n=3; 11.5%) were capable of producing advanced gestations at similar rates (P>0.05). Based on these results, it may be concluded that supplementation of both maturation and pre-maturation does not impair embryonic development. Additionally, cloned embryos produced from blocked oocytes are able to establish advanced gestation in cattle.
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Jackson, Heather Bird. "Distribution of chemistry and sexual fecundity in the lichenized-fungi, Xanthoparmelia cumberlandia and Xanthoparmelia coloradoensis on Boulder Mountain, Aquarius Plateau, UT." BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/206.
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Three aspects of Xanthoparmelia cumberlandia and Xanthoparmelia coloradoënsis populations found at two elevations are explored: clustering of secondary chemicals and the resulting implications for taxonomic distinctions, the usefulness of thallus size as an indirect measure of sexual fecundity, and the frequency of sexual reproduction.
First, we use clustering of 46 chemicals produced by X. cumberlandia and X. coloradoënsis to evaluate the adequacy of the current taxonomic distinction between them. Using principal components analysis and UPGMA, we find that the currently recognized species boundaries indicated by the presence of stictic acid in X. cumberlandia and salazinic acid in X. coloradoënsis are supported by distinct differences in their chemotypes (combinations of secondary chemicals). Norstictic acid, which the literature also associates with X. cumberlandia, is found frequently in both X. cumberlandia and X. coloradoënsis, and is not a good distinguishing characteristic. No chemical difference between sexually fecund and sterile individuals was found.
Second, we test the claim that thallus size can be used as an indirect measure of sexual fecundity. By comparing the number of apothecia, the total area of the apothecia, and the presence or absence of apothecia with thallus area, we found positive correlations between these measures of sexual fecundity and thallus size which are statistically significant. However, the total variation explained by these predictors is limited, and is significantly affected by elevation and micro-environmental features such as proximity to trees. We conclude that size is not a reliable synonym for sexual fecundity in X. cumberlandia and X. coloradoënsis.
Third, we make inferences concerning the frequency of sexual reproduction based on the frequency of sexual structures, rare chemicals, and unique chemotypes. We predicted that sexual reproduction would be more frequent at lower elevations, consistent with a common pattern found in plants and animals. The frequency of sexual structures indicates that sexual reproduction is more common at the lower elevation, while frequency of rare chemicals and chemotypes implies that outcrossing is more common at the upper elevation. Since these indicators lead to opposing conclusions, we encourage the use of molecular markers to estimate the frequency of outcrossing directly.
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Rey, Olivier. "Systèmes de reproduction et scénarios d’invasion chez la petite fourmi de feu, Wasmannia auropunctata." Thesis, Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0046/document.
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Cette thèse vise à améliorer notre connaissance des processus évolutifs et écologiques liés aux invasions biologiques au travers de l'étude de populations envahissantes et non envahissantes de la petite fourmi de feu, Wasmannia auropunctata. Cette espèce présente un polymorphisme du système de reproduction original. Dans les populations ancestrales, les reines et les mâles se reproduisent selon le mode de reproduction sexué classique des hyménoptères (haplo-diploïde). Dans d'autres populations, les reines sont parthénogénétiques et les mâles sont produits de manière clonale via les œufs pondus par la reine. Ces reines et ces mâles produisent néanmoins des ouvrières stériles sexuellement. Ce mode de reproduction clonal semble associé indirectement au succès d'invasion des populations. Dans un premier temps nous avons identifié les mécanismes sous-jacents au système de reproduction des populations clonales. Nos résultats montrent que les reines utilisent la parthénogenèse automictique associée à une réduction du taux de recombinaison pour la production de reines, l'androgenèse pour la production des mâles et la reproduction sexuée pour la production d'ouvrières stériles. La fixation des génomes parentaux dans les descendances successives permet la reproduction entre individus d'une même cohorte en évitant la dépression de consanguinité dans la descendance ouvrière. Nous avons ensuite montré que le changement de système de reproduction de la sexualité vers la clonalité est associé à un changement adaptatif permettant aux ouvrières des populations clonales de mieux tolérer les températures stressantes caractéristiques des localités envahies, comparativement aux ouvrières des populations sexuées ancestrales. Enfin, l'utilisation d'une approche multidisciplinaire couplant des modèles de distribution d'espèces, des analyses de génétique des populations et des expériences en laboratoire, nous a permis de montrer que les changements évolutifs clefs associés au succès d'invasion des populations, ont lieu dans des habitats marginaux de l'aire native, avant la dispersion vers des localités distantes caractérisées par des conditions environnementales similairesThe main goal of this thesis is to provide new insights on the evolutionary processes associated to biological invasions through the study of invasive and non-invasive populations of the little fire ant, W. auropunctata. This species is characterised by an eccentric breeding system polymorphism. In ancestral populations, queens and males reproduce following the classical sexual reproduction system of hymenopteran species (haplo-diploid). In some other populations, queens reproduce by parthenogenesis and the males are reproduced clonally through queens' eggs. These clonal queens and males nevertheless produce sterile workers sexually. Interestingly this clonal reproduction seems indirectly associated with the invasive success of populations. In this study, we first identified the mechanisms underlying the breeding system of clonal populations. Our results indicate that queens use automictic parthenogenesis associated with a drastic reduction of meiotic recombination rate, androgenesis and sexual reproduction for the production of queens, males, and sterile workers respectively. The fixation of parental genomes in the successive generations allows individuals from the same cohort to reproduce together avoiding inbreeding depression in their worker offspring. We also found that the change of breeding system from sexuality to clonality is associated with an adaptive change that allow workers from clonal populations to better tolerate the stressing temperatures of invaded areas better than workers from ancestral sexual populations. Finally, we used a developed mutlidisciplinary approach combining niche modelling, genetic analyses and laboratory experiments, and found that the above evolutionary changes occur within the native range in marginal habitats prior to long-distance dispersal events into localities that display similar environmental conditions
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Erdmann, Georgia. "Community structure, trophic ecology and reproductive mode of oribatid mites (Oribatida, Acari) in forest ecosystems." Thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://hdl.handle.net/11858/00-1735-0000-000C-B7E7-7.
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Philipp, H. Schiffer [Verfasser], Einhard [Akademischer Betreuer] Schierenberg, and Guenter [Akademischer Betreuer] Plickert. "A genomic perspective on variations in the molecular toolkit for development and on the evolution of parthenogenesis in Nematoda / Schiffer Philipp H.. Gutachter: Einhard Schierenberg ; Guenter Plickert." Köln : Universitäts- und Stadtbibliothek Köln, 2015. http://d-nb.info/1069985821/34.
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Rascado, Tatiana da Silva. "Produção de embriões por fecundação in vitro e ativação partenogenética visando o isolamento de células tronco embrionárias felinas /." Botucatu, 2009. http://hdl.handle.net/11449/94582.
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Orientador: Fernanda C. Landim AlvarengaBanca: Maria Denise Lopes
Banca: Mayra Elena Ortiz D'Avila Assumpção
Resumo: O objetivo deste estudo foi aprimorar os protocolos de produção in vitro de embriões e de ativação partenogenética visando o isolamento e o cultivo de células tronco embrionárias felinas. Os CCOs-I foram obtidos a partir de ovários de gatas adultas e maturados in vitro. No experimento I, os CCOS foram fecundados e os embriões cultivados nos meios SOFaa e FOC. Foram comparadas as taxas de clivagem e a produção de blastocistos. A análise estatística foi realizada por meio da análise de variância e a viabilidade embrionária foi avaliada por sondas fluorescentes (Hoechst e iodeto de propídio). Não houve diferenças significativas entre os meios de cultivo, os quais apresentaram taxas de clivagem de 50,5±9,47 e 63,75±5,9 (P>0,05) e de produção de blastocistos em relação ao total de oócitos fecundados de 18±5,07 e 33,2±3,71 (P>0,05) para FOC e SOF respectivamente. No experimento II, os CCOs maturos foram submetidos a três diferentes protocolos de ativação partenogenética: 1-ionomicina associada ao cicloheximide; 2-ionomicina associada ao roscovitine e 3-ionomicina associada ao estrôncio, os quais foram comparados entre si e ao controle quanto às taxas de ativação, clivagem e desenvolvimento embrionário, sendo cultivados em SOFaa por 72 horas após a ativação. Para tais avaliações, oócitos e embriões foram corados com Hoechst 33342 e examinados em microscópio invertido. Como análise estatística foi utilizado o teste qui-quadrado. Não houve diferença significativa entre os tratamentos quanto à taxa de oócitos ativados (69,9%, 76,6% e 64,6%, para tratamento 1, 2 e 3 respectivamente) (P>0,05) nem quanto às taxas de clivagem (46,6%, 46,73% e 32,32%, para tratamento 1, 2 e 3 respectivamente) (P>0,05), mas sim entre estes e o controle (36% e 12%, respectivamente, para taxa de oócitos ativados e taxas de clivagem) (P<0,05). Quanto ao desenvolvimento... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The objective of this study was to improve the existent protocols for in vitro embryos production and parthenogenetic activation in cats, aiming the isolation and culture of feline embryonic stem cells. COCs-I were collected from adult queens's ovaries and matured in vitro. In the experiment I, COCs were fertilized and embryos cultured in two culture media, SOFaa and FOC. In both media the cleavage rate and blastocysts production were compared. Fluorescents probes (Hoechst and propidium iodide) were utilized to estimate embryo viability. The statistical analysis was realized through the ANOVA. No statistical difference was observed between culture media. The cleavage rates considering the total number of fertilized oocytes were 50.5±9.47 and 63.75±5.9 (P>0.05) for FOC and SOF medium respectively. Similarly, the blastocysts production rates were 18±5.07 and 33.2±3.71 (P>0.05) for FOC and SOF, respectively. In experiment II matured COCs were submitted to three parthenogenetic activation protocols: 1- ionomycin associated to cycloheximide; 2 - ionomycin associated to roscovitine; 3 - ionomycin associated to strontium. The treatments were compared among themselves and among them and the control concerning chromatin decondensation, cleavage and embryo development rates. The parthenogenetic embryos were then cultured in SOFaa during 72 hours. To estimate chromatin status and number of nuclei, oocytes and embryos were stained with Hoechst 33342 and examined under an inverted fluorescent microscope. As statistical analyses chi-square test was utilized. No statistical difference was observed among treatments concerning activated oocytes rates (69.9%, 76.6% e 64.6%, respectively, for treatment 1, 2 and 3) (P>0.05) neither cleavage rates (46.6%, 46.73% e 32.32%, respectively, for treatment 1, treatment 1, 2, 3) (P>0.05). However, statistical difference was observed among treatments and... (Complete abstract click electronic access below)
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Vollmer, Alicia A. "Rare Parthenogenic Reproduction in a Common Reef Coral, Porites astreoides." Thesis, NSUWorks, 2018. https://nsuworks.nova.edu/occ_stuetd/464.
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Multiple stressors have caused a decline in coral populations. Broadcast spawning corals once dominated the Florida Reef Tract (FRT), but since their decline, smaller brooding corals, soft corals, and macroalgae are replacing them. Brooding corals are more resilient to current threats in part because they are reproductive throughout much of the year and their larvae are competent to settle after release. Despite the ubiquity of brooders on Florida reefs, much of their reproductive strategy remains unknown. This study aimed to examine paternity as a function of colony size and density in Porites astreoides, a common brooding coral in the FRT. Porites astreoides colonies were configured in arrays at three densities that were replicated three times. A focal colony was surrounded by six other colonies, separated from the focal colony at different distances (1m, 7m, and 15m) representing high, moderate, and low population densities, respectively. All arrays were placed in the field but were separated from the reef and naturally occurring P. astreoides colonies by at least 50 m. Four days before the new moon, colonies were transported to the laboratory for larval collection. Over a four day period, a total of 3,184 larvae were collected from 24 colonies, 13 of which released larvae over consecutive days. The resulting larvae were genotyped using seven microsatellite markers. All larvae had the exact genotypes of the colony from which the larvae were collected, i.e. maternal- egg donor. This suggested the larvae were parthenogenically produced and no sperm was used to fertilize the eggs. This is the first study to suggest that parthenogenesis is occurring in P. astreoides. In today's oceans that have been depleted of corals, parthenogenesis may be an advantageous reproductive strategy used to boost populations. However, parthenogenesis reduces the genetic diversity which could hinder successful sexual reproduction in the future causing fragmented populations.
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Duke, Connor Raymond. "Optimization of Control Source and Error Sensor Locations in Free Field Active Noise Control." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1169.
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Previous work has shown that active noise control (ANC) can be applied to axial cooling fans. Optimization of the control source and error sensor placement is desired to maximize the attenuation using ANC. A genetic algorithm was developed to find the optimal placement of control sources for a given primary source. The optimal configuration of control sources around a single primary source was shown to be a linear arrangement of the sources. This holds true for both two-dimensional as well as three-dimensional configurations. The higher-order radiation of the linear arrangement has also been verified experimentally, but the improvement in the experimental apparatus was not as dramatic as the theoretical model. Multiple flow visualization techniques have been used to find optimal near field error sensor locations. When there is little obstruction to the flow field of the fan, minimal airflow is found along the near field null that is created by minimizing the sound power of the system. Surface mounting of the error sensors can lead to a small increase in the signal-to-noise ratio of the error sensors if vortices exist in the near field of the fan due to obstructions in the main flow. It has also been shown that the introduction of the ANC system does not affect the flow field of the fan.
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Sherwood, David Alan. "A Simple Metabolic Switch May Activate Apomixis in Arabidopsis thaliana." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7409.
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Apomixis, asexual or clonal seed production in plants, can decrease the cost of producing hybrid seed and enable currently open pollinated crops to be converted to more vigorous and higher yielding hybrids that can reproduce themselves through their own seed. Sexual reproduction may be triggered by a programmed stress signaling event that occurs in both the meiocyte, just prior to meiosis, and later in the egg just prior to embryo sac maturation. The prevention of stress signaling and the activation of a pro-growth signal prior to meiosis triggered apomeiosis, the first half of apomixis. The same approach was used prior to embryo sac maturation to trigger parthenogenesis, the second half of apomixis. This discovery suggests that apomixis exists as a program that can be activated by the appropriate metabolic signal at the appropriate developmental stages. Therefore, apomixis may be alternative mode of reproduction rather a ‘broken’ form of sexual reproduction.
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Niciura, Simone Cristina Méo. "Interação núcleo-citoplasmática em embriões e expressão de genes "imprinted" em fetos bovinos produzidos in vivo, in vitro e partenogenéticos /." Jaboticabal : [s.n.], 2005. http://hdl.handle.net/11449/105949.
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Orientador: Joaquim Mansano GarciaBanca: Flávio Vieira Meirelles
Banca: Claudia Lima Verde Leal
Banca: Vera Fernanda Martins Hossepian de Lima
Banca: Gisele Zoccal Mingoti
Resumo: A maturação oocitária é marcada pela retomada da primeira divisão da meiose, com progressão do estádio de Vesícula Germinativa (GV) da Prófase I até a Metáfase II (MII), e inclui todos os eventos necessários para que o oócito expresse seu potencial máximo de desenvolvimento após a fecundação. Para avaliarmos a eficiência da maturação in vitro (MIV), utilizamos oócitos classificados em viáveis (graus I, II e III) e inviáveis (atrésico e desnudo), e acompanhamos a progressão nuclear e a distribuição dos grânulos corticais (GC) como indício de maturação citoplasmática, após MIV em TCM 199 com soro fetal bovino, hormônios, antibiótico e piruvato, por 24h em 5% de CO2 em ar. Maturação nuclear (78,4-87,8%) e citoplasmática (GC periféricos; 67,2-79,3%) foram semelhantes entre as diferentes classes de oócitos e apresentaramse como eventos independentes. Para o acompanhamento dos eventos desencadeados pelo espermatozóide, avaliamos a dinâmica nuclear e de microtúbulos, em intervalos de 2h, após fecundação in vitro (FIV), em meio TALP com heparina, PHE e sêmen preparado em gradiente de Percoll. Observamos que o estádio de MII foi predominante de 2 a 8h; MII e Anáfase/Telófase (A/T) predominaram às 10h; MII, A/T e estádio pronuclear (PN) de 14 a 16h; e PN a partir de 18h. A penetração do espermatozóide ocorreu após 4h da inseminação dos oócitos; a diferenciação dos PN 14 masculino e feminino pelo tamanho foi possível de 14 a 18h e a singamia ocorreu a partir de 24h. O período de 10h pode ser suficiente para que a FIV seja efetiva em oócitos bovinos, nas condições aqui descritas.
Abstract: We aimed to evaluate events involved in in vitro maturation, fertilization and development, and parthenogenetic activation of bovine oocytes assessed by nuclear-cytoplasmic interaction and gene expression. Oocyte morphological selection did not affect nuclear maturation (78.4-87.8%) and cytoplasmic cortical granule distribution (67.2-79.3%). Following nuclear and microtubular dynamics after fertilization (IVF), we observed sperm penetration 4h after insemination; male and female pronuclei differentiation by size from 14 to 18h; syngamy after 24h; and sufficient co-incubation of spermatozoa and oocytes for 10h. Pronuclear transfer to study the interaction between nucleus (N) and cytoplasm (C) in parthenogenetic embryos produced by ionomycin followed by strontium (S) or 6-DMAP (D) was assessed by cleavage, eight-cell, and blastocyst development rates: CSND (76.5, 36.4, and 6.8%) and CDNS (69.5, 25.0, and 4.9%). S cytoplasm promoted dominant effect on D nucleus. Higher rates of developmental arrest up to the eight-cell stage were observed by the combination of cytoplasm and nucleus produced by the two different activation treatments. We recovered parthenogenetic D fetuses on Day 35, which were small but normal in formation and in appearance of chorio-alantoic membranes. Genomic imprinting of IGF2 was observed, but XIST was maternally expressed in extra-embryonic tissues. In vitro culture promoted higher expression of IGF2 and H19 genes and also increased IGF2/IGF2r ratio in IVF embryos compared to in vivo produced ones.
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Niciura, Simone Cristina Méo [UNESP]. "Interação núcleo-citoplasmática em embriões e expressão de genes imprinted em fetos bovinos produzidos in vivo, in vitro e partenogenéticos." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/105949.
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A maturação oocitária é marcada pela retomada da primeira divisão da meiose, com progressão do estádio de Vesícula Germinativa (GV) da Prófase I até a Metáfase II (MII), e inclui todos os eventos necessários para que o oócito expresse seu potencial máximo de desenvolvimento após a fecundação. Para avaliarmos a eficiência da maturação in vitro (MIV), utilizamos oócitos classificados em viáveis (graus I, II e III) e inviáveis (atrésico e desnudo), e acompanhamos a progressão nuclear e a distribuição dos grânulos corticais (GC) como indício de maturação citoplasmática, após MIV em TCM 199 com soro fetal bovino, hormônios, antibiótico e piruvato, por 24h em 5% de CO2 em ar. Maturação nuclear (78,4-87,8%) e citoplasmática (GC periféricos; 67,2-79,3%) foram semelhantes entre as diferentes classes de oócitos e apresentaramse como eventos independentes. Para o acompanhamento dos eventos desencadeados pelo espermatozóide, avaliamos a dinâmica nuclear e de microtúbulos, em intervalos de 2h, após fecundação in vitro (FIV), em meio TALP com heparina, PHE e sêmen preparado em gradiente de Percoll. Observamos que o estádio de MII foi predominante de 2 a 8h; MII e Anáfase/Telófase (A/T) predominaram às 10h; MII, A/T e estádio pronuclear (PN) de 14 a 16h; e PN a partir de 18h. A penetração do espermatozóide ocorreu após 4h da inseminação dos oócitos; a diferenciação dos PN 14 masculino e feminino pelo tamanho foi possível de 14 a 18h e a singamia ocorreu a partir de 24h. O período de 10h pode ser suficiente para que a FIV seja efetiva em oócitos bovinos, nas condições aqui descritas.
We aimed to evaluate events involved in in vitro maturation, fertilization and development, and parthenogenetic activation of bovine oocytes assessed by nuclear-cytoplasmic interaction and gene expression. Oocyte morphological selection did not affect nuclear maturation (78.4-87.8%) and cytoplasmic cortical granule distribution (67.2-79.3%). Following nuclear and microtubular dynamics after fertilization (IVF), we observed sperm penetration 4h after insemination; male and female pronuclei differentiation by size from 14 to 18h; syngamy after 24h; and sufficient co-incubation of spermatozoa and oocytes for 10h. Pronuclear transfer to study the interaction between nucleus (N) and cytoplasm (C) in parthenogenetic embryos produced by ionomycin followed by strontium (S) or 6-DMAP (D) was assessed by cleavage, eight-cell, and blastocyst development rates: CSND (76.5, 36.4, and 6.8%) and CDNS (69.5, 25.0, and 4.9%). S cytoplasm promoted dominant effect on D nucleus. Higher rates of developmental arrest up to the eight-cell stage were observed by the combination of cytoplasm and nucleus produced by the two different activation treatments. We recovered parthenogenetic D fetuses on Day 35, which were small but normal in formation and in appearance of chorio-alantoic membranes. Genomic imprinting of IGF2 was observed, but XIST was maternally expressed in extra-embryonic tissues. In vitro culture promoted higher expression of IGF2 and H19 genes and also increased IGF2/IGF2r ratio in IVF embryos compared to in vivo produced ones.
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Lashermes, Philippe. "Gynogenese et androgenese in vivo chez le mais (zea mays l. ) : etudes genetique et physiologique, utilisation en selection." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF21058.
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Timmermans, Iris. "Stratégies de reproduction au sein du genre Cataglyphis (Hymenoptera :Formicidae): analyse comparative." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210238.
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Les fourmis, comme tous les Hyménoptères, sont caractérisées par un mode de détermination du sexe de type haplodiploïde. Les femelles sont issues d’œufs fertilisés et sont diploïdes alors que les mâles se développent à partir d’œufs non fertilisés par parthénogenèse arrhénotoque, et sont haploïdes. A quelques rares exceptions près, le déterminisme de la caste au sein du sexe femelle est réalisé de manière épigénétique :seules les larves diploïdes les mieux nourries et/ou celles produites après le repos hivernal se développent en femelles sexuées (reines), les autres en femelles non reproductrices (ouvrières). Récemment, plusieurs travaux ont montré que les reines de quelques espèces de fourmis sont capables de maximiser leur succès reproductif en exploitant de manière conditionnelle la reproduction sexuée et asexuée. Alors que les ouvrières sont produites à partir d’œufs fertilisés par reproduction sexuée classique, les jeunes femelles reproductrices sont issues d’œufs diploïdes produits par parthénogenèse thélytoque et sont, par conséquent, génétiquement très similaires à leur mère. L’espèce Cataglyphis cursor est le premier modèle chez lequel cette stratégie reproductrice a été mise en évidence (Pearcy et al. 2004b). Les sociétés de C. cursor sont strictement monogynes, les reines sont hautement polyandres et utilisent la reproduction sexuée et asexuée pour la production d’ouvrières et de femelles reproductrices, respectivement. La combinaison de la polyandrie et de la reproduction thélytoque permet aux reines de C. cursor d’optimiser le taux de transmission de leurs gènes via des filles reproductrices, tout en assurant une diversité génétique maximale au sein de la force ouvrière. Par ailleurs, les ouvrières de C. cursor ont conservé leurs ovaires et se reproduisent en l’absence de reine. Elles produisent alors des mâles (par parthénogenèse arrhénotoque), des femelles sexuées et des ouvrières (par parthénogenèse thélytoque) (Cagniant, 1973)Les travaux réalisés dans le cadre de cette thèse de doctorat visent à déterminer si les stratégies reproductrices remarquables exploitées par C. cursor sont propres à l’espèce ou si elles ont évolué au sein de plusieurs espèces du genre. A cette fin, nos recherches s'articulent autour de 2 axes complémentaires. Premièrement, nous avons approfondi l'étude des stratégies reproductrices chez C. cursor en nous concentrant sur deux aspects. (i) Plusieurs hypothèses ont été proposées pour justifier l’évolution de la polyandrie chez les fourmis. Nos travaux ont testé et éliminé trois d’entre elles pour C. cursor :l’hypothèse de la limitation spermatique, celle des coûts des mâles diploïdes et celle selon laquelle une plus grande variabilité génétique des ouvrières améliorerait la division du travail. (ii) Nous avons mis en évidence l’existence d’un contrôle des reines dans le déterminisme de la caste chez cette espèce. Les reines ne produisent des œufs thélytoques qu’au début du printemps, lorsque les ouvrières élèvent les œufs en sexués. Plus tard dans la saison, les reines ne produisent plus que des œufs fertilisés qui se développeront en ouvrières.
Deuxièmement, à titre comparatif, nous avons analysé la structure socio-génétique de deux autres espèces de Cataglyphis :C. sabulosa et C. livida. Ces deux espèces sont monogynes et polyandres. Leurs ouvrières sont capables de pondre des œufs haploïdes mais seules les ouvrières de C. sabulosa ont produits des œufs diploïdes thélytoques. Aucune des reines des deux espèces n’utilisent la parthénogenèse thélytoque pour produire des femelles sexuées.
L’ensemble des résultats obtenus dans notre étude ont été replacés dans une perspective évolutive afin de préciser quand la polygynie, la polyandrie et la thélytoquie seraient apparues dans la phylogénie des Cataglyphis.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Mezzalira, Joana Claudia. "Efeito da heteroplasmia na densidade celular e desenvolvimento embrionário in vitro de embriões bovinos clonados por transferência nuclear de célula somática." Universidade do Estado de Santa Catarina, 2009. http://tede.udesc.br/handle/handle/892.
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In somatic cell nuclear transfer (SCNT), the type of the recipient cytoplast plays a key role on nuclear reprogramming. Distinct cytoplasts and karyoplasts and different activation protocols were used for bovine embryo cloning aiming to evaluate the effect of the type of cytoplast (oocyte and/or zygote) and the activation protocol (chemical, AQ, or spermatic, AE) on development of cloned blastocysts produced by handmade cloning (HMC). After 17 h of in vitro maturation (MIV), 2,946 oocytes were enucleated by manual bisection resulting in either MII cytoplasts (enucleated) or MII karyoplasts (non-enucleated). An additional group of 2,368 oocytes, in vitro-fertilized (FIV) for 6 h, were manually bisected and segregated in either FIV cytoplasts (enucleated) or FIV karyoplasts (non-enucleated). Cells from a primary culture previously established from a skin biopsy from an adult female bovine were used as nuclei donors (karyoplast CS). Structures were allocated to (a) control groups: FIV; parthenogenesis using zona-intact (PG c/) or zona-free oocytes (PG s/); and clones by SCNT; or (b) experimental groups: G1, FIV cytoplast + MII cytoplast + CS karyoplast; G2, MII cytoplast + FIV karyoplast; G3, FIV cytoplast + FIV karyoplast; G4, FIV cytoplast + FIV cytoplast + CS karyoplast; and G5, MII cytoplast + MII karyoplast. Following electrofusion, experimental groups G1 to G5 were allocated to sub-groups of either sperm-mediated (AE) or additional chemical (AQ) activation. The in vitro culture was carried out in the WOW (wellof- the-well) system. After 20 replications, cleavage (D2) and blastocyst (D7) rates were compared by the χ2 test, with values for total cell number and cell allocation in the blastocyst, determined by differential staining, being evaluated by ANOVA, with pairwise comparisons by the Tukey test, for P<0.05 (P<0.05). The only experimental group that yielded a blastocyst development similar to the FIV (27.0%) and SCNT (31.4%) control groups was the subgroup G1 AE (28.2%). This fact may be attributed to a more proper synchrony between the karyoplast and cytoplasts and/or to a more suitable activation process. Embryo development in subgroups G1 AQ (13.7%), G4 AQ (6.4%) and G4 AE (8.7%) was lower than in G1 AE, possibly due to a higher degree of asynchrony in the activation process or cell cycle. The lack of development in groups G2 and G3, irrespective of the activation protocol, was possibly due to the manipulation process during a highly sensible biological period. Likewise, the low cleavage (57.0%) and the lack of development in group G5 (spontaneous activation) in fact showed that the manipulation induced weak spontaneous oocyte activation. In general, total cell number and cell allocation were similar between groups with development to the blastocyst stage. In conclusion, the activation process appeared to be as important to embryo development as the type of cytoplast or karyoplast used for embryo reconstruction. The production of cloned bovine embryos using a more physiological activation process (AE) was proven as a viable procedure, with efficiency rates observed in subgroup G1 AE being similar to groups FIV or TNCS
Na clonagem por transferência nuclear com célula somática (TNCS), o tipo de citoplasto receptor desempenha papel chave na reprogramação nuclear. Distintos citoplastos e carioplastos e condições de ativação foram utilizadas na reconstrução de embriões bovinos com o objetivo de avaliar o efeito do tipo de citoplasto (oócito e/ou zigoto) e do método de ativação (química, AQ, ou espermática, AE) no desenvolvimento de blastocistos clonados produzidos pela técnica de clonagem manual (Handmade Cloning, HMC). Após 17 h de maturação in vitro (MIV), 2.946 oócitos foram enucleados por bissecção manual, resultando em hemi-oócitos enucleados (citoplastos MII) e não enucleados (carioplastos MII). Outros 2.368 oócitos submetidos a 6 h de fecundação in vitro (FIV) foram bisseccionados manualmente e segregados em hemi-zigotos enucleados (citoplastos FIV) e não enucleados (carioplastos FIV). Células de um cultivo celular estabelecido a partir da biópsia auricular de uma fêmea bovina adulta foram utilizadas como núcleos doadores (carioplasto CS). As estruturas foram dispostas em (a) grupos controle: FIV; partenogênese com oócitos com (PG c/) ou sem zona pelúcida (PG s/); e clone por TNCS; ou (b) grupos experimentais: G1, citoplasto FIV + citoplasto MII + carioplasto CS; G2, citoplasto MII + carioplasto FIV; G3, citoplasto FIV + carioplasto FIV; G4, citoplasto FIV + citoplasto FIV + carioplasto CS; e G5, citoplasto MII + carioplasto MII. Após a eletrofusão das estruturas, os grupos experimentais G1 a G45 foram divididos em subgrupos de AQ ou AE. O cultivo in vitro foi realizado pelo sistema WOW (well-of-the-well). Após 20 repetições, as taxas de clivagem (D2) e blastocisto (D7) foram comparadas pelos testes de χ2 e os valores para o número total de células e a alocação das linhagens celulares nos blastocistos, determinados por coloração diferencial, foram avaliados por análise de variância, com pareamento comparativo pelo teste de Tukey, para P<0,05. O único grupo experimental que apresentou desenvolvimento embrionário no D7 semelhante aos controles FIV (27,0%) e TNCS (31,4%) foi o subgrupo G1 AE (28,2%). Isso pode ser atribuído a uma melhor sincronia do ciclo celular entre citoplastos e/ou carioplasto e um mais adequado processo de ativação. O desenvolvimento embrionário nos grupos G1 AQ (13,7%), G4 AQ (6,4%) e G4 AE (8,7%) foi menor do que o G1 AE, possivelmente devido à assincronia do processo de ativação ou ciclo celular. O desenvolvimento embrionário nulo dos grupos G2 e G3, independente da ativação, possivelmente foi decorrente da manipulação das estruturas em um momento biologicamente sensível. Da mesma forma, a baixa clivagem (57,0%) e o desenvolvimento nulo no grupo G5 de ativação espontânea demonstraram de fato que a manipulação estimulou o processo de ativação embrionária de forma sub-limiar. Em geral, não houve diferença no número de células e alocação celular nos grupos onde houve desenvolvimento até o estádio de blastocisto. Conclui-se que o processo de ativação foi tão significativo para o desenvolvimento embrionário que o tipo de citoplasto e carioplasto usados na reconstrução embrionária. A produção de embriões clones com um método mais fisiológico de ativaçao (AE) mostrou-se como um procedimento viável, obtendo-se no grupo G1 AE a mesma eficiência observada na FIV ou na TNCS
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Kremer, Natacha. "Évolution de la dépendance dans les symbioses à Wolbachia : étude du genre Asobara (Hymenoptera : braconidae)." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10141.
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Les associations entre organismes eucaryotes et micro-organismes sont fréquemment observées dans la nature et s’étendent le long du continuum parasitisme-mutualisme. Si de nombreuses associations symbiotiques ont été bien caractérisées, leur mise en place et leur évolution ont été rarement étudiées. Les bactéries intracellulaires Wolbachia induisent des effets très différents, variant du parasitisme de la reproduction chez les Arthropodes au mutualisme chez les Nématodes. Nous nous sommes ici intéressés à l’hyménoptère Asobara tabida, rare espèce où Wolbachia est obligatoire pour l’ovogenèse de son hôte Arthropode, de façon à étudier les mécanismes à l’origine d’une transition évolutivement récente. Nous avons tout d’abord étudié la variabilité de la dépendance vis-à-vis de Wolbachia au sein du genre Asobara. Par diverses approches de transcriptomique, nous avons ensuite caractérisé les mécanismes moléculaires impliqués dans la dépendance chez A. tabida, et mis en évidence des processus impliqués dans la mort cellulaire programmée, l’immunité (sens large) et le développement. Enfin, nous avons étudié l’impact de Wolbachia sur la physiologie de son hôte, en étudiant le métabolisme du fer et plus généralement l’immunité dans diverses associations symbiotiques. Ces études montrent que la dépendance n’est pas forcément associée à l’apport de nouvelles fonctions et pourrait au contraire être le reflet de processus compensatoires mis en place par l’hôte, en réponse aux perturbations physiologiques induites par le symbiote. Ces résultats appellent à considérer les effets et les conséquences de ces symbiotes au delà des mécanismes qui permettent leur maintien dans les populationsAssociations between eukaryotes and micro-organisms are frequently observed in nature and range along the continuum between parasitism and mutualism. Numerous associations have already been well described; however the origin and the evolution of these associations are rarely studied. We focused on the intracellular bacterium Wolbachia, which induces very different phenotypic effects, ranging from facultative reproductive parasitism in Arthropods to obligatory mutualism in Nematodes. Here we studied the hymenopteran Asobara tabida, a rare species in which Wolbachia is necessary for oogenesis completion of its Arthropod host, in order to investigate the mechanisms underlying an evolutionarily recent transition. We first studied the variability of dependence to Wolbachia within the Asobara genus. Using various transcriptomic approaches, we next characterized molecular echanisms involved in dependence between A. tabida and Wolbachia, and highlighted processes implicated in programmed cell death, immunity (broad sense) and development. Finally, we examined to what extent Wolbachia impacts host physiology, by studying iron metabolism and global immunity in various symbiotic associations. These studies highlight that dependence is not always linked with the provision of a new function. It could rather reflect host compensatory mechanisms in response to physiological perturbations induced by the presence of symbiont. More generally, these results invite to consider the effects and the consequences of symbionts over the mechanisms allowing their persistence within populations
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Hellemans, Simon. "Ecology and reproduction of neotropical soil-feeding termites from the Termes group." Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/286072.
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The traditional view of a lifelong monogamy between a king and a queen has recently been challenged in termites. In several species, multiple parthenogenetically-produced secondary queens replace the primary queen and mate with the primary king; this strategy is referred to as “Asexual Queen Succession” (AQS). The aim of my thesis was to investigate the modalities of reproduction and the ecology of neotropical soil-feeding termites from the Termitinae, with a focus on the inquiline termite Cavitermes tuberosus in the Termes group.In the first axis, we investigated the modalities of reproduction of C. tuberosus. (i) AQS is the main reproductive strategy of this species. (ii) The evolution of AQS requires the propensity of parthenogens to develop into neotenic queens. In C. tuberosus, secondary queens develop from a developmental stage of “aspirants” which participate to the social tasks usually undertaken by workers, as long as the primary queen is alive. (iii) In AQS species, a female-biased sex ratio is expected in the dispersing reproductives. In C. tuberosus, sex ratio varies among years and according to the type of reproductives, and the population sex ratio is balanced. These results raise hints on queen-king conflict over the sex ratio.In the second axis, we described the ecology and symbioses of C. tuberosus. (iv) Wolbachia, an endosymbiotic bacterium mainly known for manipulating the reproduction of arthropods in order to enhance its own transmission, infects all individuals in societies. This bacterium, particularly abundant in a gut-associated bacteriome, may play a role in the nutrition of C. tuberosus; both partners would have evolved a mutualistic symbiosis. (v) Inquiline termites live in a nest built by other termite species and do not forage outside. Physico-chemical measures and microbiota sequencing revealed that C. tuberosus is a generalist nest-feeder.Finally, we expanded our study of the breeding systems in the phylogenetic proximity of C. tuberosus. (vi) We described Palmitermes impostor, a new genus and species as a sister-group to the genus Cavitermes. (vii) AQS is the main reproductive strategy in P. impostor, and queens of Spinitermes trispinosus and Inquilinitermes inquilinus are able to reproduce parthenogenetically. Therefore, it appears likely that the conditional use of sexual and asexual reproductions is a preadaptation common to the whole Termes group, and that it evolved into a stable element of their breeding system at least in some species.Overall, our results open new perspectives in the understanding of reproductive strategies in termites and their relationships with their bacterial symbionts.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Defendini, Hélène. "Bases génétiques et conséquences évolutives de la perte de sexe dans le groupe des pucerons." Electronic Thesis or Diss., Rennes, Agrocampus Ouest, 2023. http://www.theses.fr/2023NSARA094.
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La reproduction sexuée est considérée comme le mode de reproduction ancestral des eucaryotes, mais elle été perdue à plusieurs reprises dans de nombreux taxons. Comprendre les mécanismes par lesquels les lignées asexuées apparaissent et persistent dans le temps reste un défi majeur de la biologie évolutive. Au cours de ma thèse, j'ai étudié les bases génétiques ainsi que les conséquences évolutives de la perte du sexe chez les pucerons, un groupe qui présente un polymorphisme de reproduction. Le mode de reproduction ancestral des pucerons est la parthénogenèse cyclique (CP, une alternance de plusieurs générations parthénogénétiques et d'une génération sexuée), mais la parthénogenèse obligatoire (OP) est fréquemment observée dans ce groupe. Les lignées OP dérivées ne sont pas capables de produire des femelles sexuées bien qu'elles conservent souvent la capacité de produire des mâles. Pour caractériser les régions génomiques impliquées dans la transition de la reproduction CP à OP, nous avons utilisé des approches de scan génomique sur différents taxons de pucerons plus ou moins proches génétiquement et présentant des variations de mode de reproduction. Nous avons montré que la base génétique de la perte du sexe est différente entre les taxons étudiés, sans convergence apparente dans le contenu génique ou les fonctions des gènes. Ainsi, plusieurs régions génomiques indépendantes peuvent être responsables de la perte du sexe chez les pucerons, ce qui suggère qu'il existe de nombreuses voies menant à l'asexualité dans ce groupe. Ensuite, nous avons étudié les conséquences évolutives de la perte du sexe sur les traits et les gènes essentiels à la reproduction sexuée. Comme il est peu probable que les mâles produits par les lignées OP transmettent leurs gènes (les lignées CP étant généralement séparées géographiquement des lignées OP), nous avons testé la prédiction selon laquelle les traits mâles dégénèrent. La production de mâles était en effet réduite dans les lignées OP, supposément en raison de la contre-sélection, mais le succès reproductif des mâles n'était que légèrement inférieur à celui des lignées CP, probablement en raison de la sélection relâchée qui agit lentement ou d’opportunités reproductives sous-estimées. Comme les lignées OP produisent rarement des mâles et ne produisent pas de femelles sexuées, l'expression génétique des femelles parthénogénétiques n'est plus contrainte par celle des autres morphes. Nous avons donc prédit que la disparition du conflit sexuel (qui survient lorsqu'il existe différents optima spécifiques à chaque morphe pour un trait partagé par différents morphes) entraînerait des changements d’expression des gènes. Nous avons donc comparé les profils d'expression génétique des lignées CP et OP pour différents morphes du puceron du pois. Nous avons observé que l'expression des gènes chez les mâles des lignées OP tendait vers l'optimum des femelles parthénogénétiques, comme le prévoyait la théorie. Plus surprenant, les mâles et les femelles parthénogénétiques des lignées OP surexpriment systématiquement des gènes exprimés dans les gonades des morphes sexués. Ces changements dans l'expression des gènes dans les lignées OP peuvent s’expliquer par un relâchement de la sélection ou la reconversion de réseaux de gènes autrement utilisés dans les lignées sexuées. Cette thèse illustre la pertinence de l'utilisation d'espèces aux systèmes de reproduction polymorphes pour comprendre l'histoire évolutive de la perte du sexe et ses conséquencesSexual reproduction is considered the ancestral reproductive mode of eukaryotes, yet it has been lost several times in many taxa. Understanding the mechanisms by which asexual lineages appear and persist over time remains a major challenge of evolutionary biology. During my PhD, I investigated the genetic basis as well as the evolutionary consequences of sex loss in aphids, a group that displays reproductive polymorphism. The ancestral reproductive mode of aphids is cyclical parthenogenesis (CP, an alternation of several parthenogenetic generations and one sexual generation), but obligate parthenogenesis (OP) is frequently observed in this group. Derived OP lineages are not able to produce sexual females though they often retain the ability to produce males. First, to characterize genomic regions involved in the transition from CP to OP reproductive mode, we used genome scan approaches on different aphid taxa that are more or less genetically related and exhibit variation in reproductive mode. We showed that the genetic basis of sex loss is different between the studied taxa, with no apparent convergence in gene content norfunctions. Thus, several independent genomic regions may be responsible for sex loss in aphids, suggesting that there are many paths that lead to asexuality in this group. Second, we studied the evolutionary consequences of the loss of sex on traits and genes essential for sexual reproduction. Since the males produced by OP lineages are unlikely to pass on their genes (because CP lineages are usually separated from OP ones), we tested the prediction that male traits should degenerate. Male production was indeed reduced in OP lineages, supposedly resulting from counter-selection, but male reproductive success was only slightly lower than in CP lineages, presumably due to the slow action of relaxed selection orunderestimation of reproductive opportunities. As OP lineages produce rare males and also do not produce sexual females, the gene expression of parthenogenetic females in these OP lineages is no longer constrained by that of other morphs. We thus predicted that the disappearance of sexual conflict (which arises when there are different morph-specific optima for a trait shared by different morphs) would result in shifts of gene expression. We therefore compared gene expression patterns of CP and OP lineages for different morphs in the pea aphid. We observed that gene expression in males from OP lineages tended towards the parthenogenetic female optimum, as predicted by theory. More surprisingly, males and parthenogenetic females of OP lineages consistently over-expressed genes typically expressed in the gonads of sexual morphs. These changes in gene expression in OP lineages may arise from the relaxation of selection or the repurposing of gene networks otherwise used in sexual lineages. This thesis illustrates the relevance of using species with polymorphic reproductive systems to understand the evolutionary history of sex loss and its consequences
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Fisher, David Lockwood. "Comparative life history studies of sexual and parthenogenetic Liposcelis." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264839.
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Pennarossa, G. "CENTROSOME BIOGENESIS AND ADAPTIVE RESPONSE IN MAMMAL PARTHENOGENETIC CELLS." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/169555.
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Human parthenotes have been proposed as a source of embryonic stem cells despite the high incidence of aneuploidy described in parthenotes of most mammalian species. Through a comparative analysis between parthenogenetic and bi-parental cells lines we found that parthenogenetic cells are affected by chromosomal instability and centrosome amplification. We provide evidence that both alterations are determined by the lack of paternal centriole, normally contributed by the sperm at the time of fertilization, but parthenogenetic cell lines activate a series of adaptive mechanisms that allow them to proliferate and differentiate. These include down-regulation of the p53/p21 pathway, massive increase of autophagic activity and formation of a wide network of intercellular bridges with the morphological and molecular characters of blocked cell abscissions. These processes are commonly observed in transformed cells therefore parthenogenesis may be used to explore the mechanisms regulating oncogenesis and their link with self-renewal and pluripotency in human cell lines.
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Ahmad, Ruhel [Verfasser], and Albrecht [Akademischer Betreuer] Müller. "Neurogenesis from parthenogenetic human embryonic stem cells / Ruhel Ahmad. Betreuer: Albrecht Müller." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1031379878/34.
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Samandar, eweis Dureen. "Asymmetric division in single cell nematode embryos outside the Caenorhabditis genus." Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLS063.
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La division cellulaire asymétrique est un processus essentiel du développement. Ce processus ainsi que sa régulation ont fait l’objet de nombreuses études chez l’embryon de Caenorhabditis elegans. La division asymétrique de l'embryon unicellulaire est un processus conservé à travers les espèces de nématodes, cependant les caractéristiques cellulaires menant à la division sont étonnamment variables. Au cours de mon doctorat, j'ai voulu étudier ces différences en utilisant deux embryons non-C. elegans : Diploscapter pachys et Pristionchus pacificus. D. pachys est le parent parthénogénétique le plus proche de C. elegans. La polarité étant induite par le sperme chez C. elegans, on ne peut expliquer ce qui brise la symétrie chez D. pachys. Mes résultats montrent que le noyau occupe le plus souvent l’hémisphère de D. pachys qui deviendra le pole postérieur. Dans les embryons où il est astreint à un pôle par centrifugation, le noyau fini par revenir à son pôle préférentiel. Même si l’embryon est polarisé, l’agitation corticale et le cytosquelette d’actine semblent identiques aux deux pôles. D’autre part, la position du fuseau méiotique est corrélée avec la future cellule postérieure. Dans certains ovocytes, on observe des structures de microtubules émanant du fuseau méiotique combiné à un faible enrichissement en actine au future pôle postérieur. Finalement, mon principal projet de thèse montre que la polarité de D. pachys est atteinte durant la méiose, au cours de laquelle le fuseau méiotique pourrait jouer un rôle par un mécanisme présent mais inhibé chez C. elegans. Chez P. pacificus, la transgénèse biolistique a été récemment utilisée avec succès. Toutefois, par manque d’un marqueur de sélection fiable, il était illusoire de poursuivre cette approche. En conclusion, les résultats de ma thèse contribuent à une meilleure compréhension de l’embryogénèse hors C. elegans. Ils soulignent l’importance de ces espèces dans l’optique d’études comparativesAsymmetric cell division is an essential process of development. The process and its regulation have been studied extensively in the Caenorhabditis elegans embryo. Asymmetric division of the single-cell embryo is a conserved process in nematode species, however, the cellular features leading up to division are surprisingly variable. During my PhD, I aimed to study these differences by using two non-C. elegans embryos: Diploscapter pachys and Pristionchus pacificus. D. pachys is the closest parthenogenetic relative to C. elegans. Since the polarity cue in C. elegans is brought by the sperm, how polarity is triggered in D. pachys remains unknown. My results show that the nucleus inhabits principally the hemisphere of the D. pachys embryo that will become the posterior pole. Moreover, in embryos where the nucleus is forced to one pole by centrifugation, it returns to its preferred pole. Although the embryo is polarized, cortical ruffling and actin cytoskeleton at both poles appear identical. Interestingly, the location of the meiotic spindle also correlates with the future posterior cell. In some oocytes, a slight actin enrichment along with unusual microtubule structures emanating from the meiotic spindle are observed at the future posterior pole. Overall, my main PhD project shows that polarity of the D. pachys embryo is attained during meiosis wherein the meiotic spindle could potentially be playing a role by a mechanism that may be present but suppressed in C. elegans. For P. pacificus, biolistic transgenesis has been shown recently successful. However, due to a lack of a stringent selection marker, the continuation of this project was unfeasible during my PhD. Altogether, the results of my PhD add to the understanding of non-C. elegans early embryogenesis and emphasizes on the importance of using these species for comparative studies
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Sukumaran, Sandhya. "Genotoxic responses and population level effects of mutagen exposure in bisexual and parthenogenetic Artemia." Thesis, University of East Anglia, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551144.
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Genotoxic chemicals in the aquatic environment induce DNA damage and mutations causing emergent effects on populations and ecosystem. The vulnerability of organisms to these chemicals also depends on life histories and reproductive mode. This thesis explored the population consequences of exposure to a reference genotoxicant/mutagen, ethyl methane sulfonate in sexual and asexual species of Artemia. A holistic approach was adopted by studying molecular markers (comet assay and ISSR), whole organism (changes in demographic parameters) and population level consequences (prospective and retrospective analysis of effects on population growth rate ft.) in laboratory conditions. EMS elicited predictable genotoxic responses in both the species of Artemia in comet assay and ISSR profiling. The genotoxic responses were associated with reductions in whole organism performance and population growth in the parental generation of both the species and Fl and F2 generations of asexual species showing the predictability of biomarkers about population level effects, more efficiently in asexuals. Population growth rate was proportionally more sensitive to juvenile survival whereas the effect of EMS on juvenile fertility contributed more to the variations in population growth rate in both the species in perturbation analysis and this effect was due to the high growth rate of Artemia. Simulations of lower population growth rate in the model showed that, adult fertility and survival are also of importance. Asexual species showed substantial reductions in whole organism performance and population growth rate in all the three generations whereas in sexual species substantial effects occurred only in parental generation. Thus the inability of asexual species to purge deleterious mutations by a genotoxicant/mutagen was demonstrated conclusively. These findings provided strong empirical evidence of the evolutionary hypotheses about the advantages and disadvantages of asexual and sexual reproduction. Thus asexual species may be vulnerable to extinction in environmentally challenging conditions affecting community structure and ecosystem dynamics.
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Knebelsberger, Thomas. "Geographische Parthenogenese bei der Schabe Phyllodromica subaptera (Blattoptera, Blattellidae, Ectobiinae) und Revision des subaptera-Artenkomplexes." Diss., kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/8966/.
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Reichel, Katja. "Effets de la reproduction partiellement asexuée sur la dynamique des fréquences génotypiques en populations majoritairement diploïdes." Thesis, Rennes, Agrocampus Ouest, 2015. http://www.theses.fr/2015NSARC123/document.
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Les systèmes reproducteurs déterminent comment le matériel génétique est transmis d’une génération à la suivante […]. Les espèces qui combinent de la reproduction sexuée et asexuée/clonale sont très répandues [… mais] l’effet de leur système reproducteur sur leur évolution reste énigmatique et discuté.L’objectif de cette thèse est de modéliser la dynamique des fréquences génotypiques d’une population avec une combinaison de reproduction sexuée et/ou clonale dans des cycles de vie principalement diploïdes [. … Un] modèle du type chaine de Markov avec temps et états discrets sert de base mathématique pour décrire [leurs] changements […] au cours du temps.Les résultats montrent que la reproduction partiellement asexuée peut en effet modifier la dynamique de la diversité génomique par rapport à une reproduction strictement sexuée ou strictement asexuée. […] L’histoire démographique a un rôle important pour les organismes partiellement clonaux et doit être prise en compte dans toute analyse […].Cette thèse fait des recommandations pour la collecte des données et une hypothèse de base pour l’interprétation des données de génétique/génomique […]. Ces résultats ont des retombées dans plusieurs domaines, allant de la recherche fondamentale […] à des applications en agriculture […], pêche […] et protection de la nature […]Reproductive systems determine how genetic material is passed from one generation to the next, making them an important factor for evolution. Organisms that combine sexual and asexual/clonal reproduction are very widespread [… yet] the effects of their reproductive system on their evolution are still controversial and poorly understood.The aim of this thesis was to model the dynamics of genotype frequencies under combined sexual/clonal reproduction in dominantly diploid life cycles [. … A] state and time discrete Markov chain model served as the mathematical basis to describe [their] changes […] through time.The results demonstrate that partial clonality may indeed change the dynamics of genomic diversity compared to either exclusively sexual or exclusively clonal populations. […] Time has a crucial role in partially clonal populations and needs to be taken into account in any analysis of their genomic diversity.This thesis provides recommendations for data collection and a null hypothesis for the interpretation of population genetic/genomic data […]. Moreover, it includes new methods for the analysis of genotype-based population genetic Markov chain models. These results have a high potential relevance in several areas, ranging from basic research […] to applications in agriculture […], fisheries […] and nature conservation […]
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Rosenberger, Martin Julien [Verfasser], Stefan [Akademischer Betreuer] Scheu, Mark [Akademischer Betreuer] Maraun, and Ulrich [Akademischer Betreuer] Brose. "Phylogeography in sexual and parthenogenetic European oribatida / Martin Julien Rosenberger. Gutachter: Stefan Scheu ; Mark Maraun ; Ulrich Brose. Betreuer: Stefan Scheu." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1043612831/34.
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Winger, Quinton A. "Expression of insulin-like growth factors (IGF) and their binding proteins (BP) in fertilized and parthenogenetic bovine embryos, regulators of early development." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21055.pdf.
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Bergmann, Paavo Karl [Verfasser], and Michael [Akademischer Betreuer] Heethoff. "Development and function of the genital organs in the parthenogenetic oribatid mite Archegozetes longisetosus Aoki 1965 / Paavo Karl Bergmann ; Betreuer: Michael Heethoff." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/1163397261/34.
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Coutinho, Ana Rita Sousa. "Presença da Caspase-3 ativa e das proteínas de reparo de lesões do DNA em embriões suínos ativados partenogeneticamente com alta ou baixa capacidade de desenvolvimento." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-12122007-100619/.
Full textAbstract:
Apoptose é uma forma de morte celular extremamente conservada que tem papel primordial no desenvolvimento animal e na homeostasia celular, agindo como mecanismo de controle de qualidade com a função de remover células danificadas, em excesso ou não-funcionais. Este processo tem papel importante no desenvolvimento embrionário pré-implantacional, pois as células embrionárias estão sujeitas aos danos no DNA que podem ativar mecanismos de reparo de DNA ou induzir apoptose, que culmina com a ativação da enzima caspase-3 responsável pela clivagem de vários substratos celulares. Deste modo, o presente trabalho teve como objetivos determinar a presença da Caspase-3 ativa (+casp-3) e sua influência no desenvolvimento de embriões suínos no estágio de pré-implantação, bem como investigar a detecção de proteínas que atuam no mecanismo de lesão e reparo do DNA. Foram realizados 4 experimentos com oócitos imaturos de fêmeas pré-púberes, obtidos de ovários oriundos de abatedouro, maturados in vitro (MIV) por 44-46 horas. Oócitos em metáfase II (MII) foram ativados partenogeneticamente (AP) com ionomicina e cloreto de estrôncio e cultivados in vitro em PZM3 a 38ºC e 5% CO2 em ar e alta umidade. No primeiro experimento os embriões foram classificados em 4 grupos de acordo com o tempo de clivagem e o número de células: R4 - clivado às 24 horas e com ≥4 células às 48 horas; R2 - clivado às 24 horas e com 2 ou 3 células às 48 horas; L4 - não clivado às 24 horas e com ≥4 células às 48 horas; L2 - não clivado às 24 horas e com 2 ou 3 células às 48 horas. Os embriões foram então avaliados no D-6 do CIV para determinação do índice de desenvolvimento até o estágio de blastocisto. Os embriões do grupo R apresentaram maiores índices de blastocisto, R4 - 66,1 (174/263) e R2 - 59,6 (62/104) e maior número de núcleos por blastocisto, R4 - 40,1 e R2 - 37,8, quando comparados ao grupo L, L4 - 15,4 (6/39) e L2-16,8 (13/77); L4-18,5 e L2-18,3 (Qui-quadrado e Tukey-Kramer, respectivamente, P<0,05); entretanto, não houve diferença entre os grupos R4 e R2 e L4 e L2. Para o segundo experimento utilizou-se apenas embriões R e L, classificados às 24hs do início do CIV. Ambos os grupos (R e L) foram destinados à análise de imunocitoquímica para +casp-3 fixados nos D2, D4 e D6, sendo cada um destes dias considerado um sub-experimento e realizado em manipulações diferentes. Foi observada localização citoplasmática da +casp-3 do D2 ao D6 e nuclear a partir do D5 de cultivo. A quantificação relativa da +casp-3 nos grupos R e L de cultivo foi de 2,4 vs 1,4; 1,1 vs 1,0 e 1,1 vs 1,2 para o D2, D4 e D6, respectivamente. Para avaliar a influência da +casp-3 no desenvolvimento de embriões suínos foi realizado o terceiro experimento utilizando o inibidor de caspase z-DEVD-fmk (100uM) durante a MIV, no início (D0 ao D2) ou no final (D4 ao D6) do cultivo. Embriões produzidos sem inibidor foram usados como controle. A presença do inibidor durante a MIV e no final do cultivo não afetou os índices de blastocistos. No entanto, a presença do inibidor durante as primeiras 48 horas de cultivo resultou em maior índice de blastocisto do que o grupo controle, 55,1 (59/107) e 37,5 (39/104) (Qui-quadrado, P<0,05). O último experimento foi realizado para investigar a presença das proteínas de reparo de lesão de DNA, γH2AX, 53BP1, NSB1 e RAD52, em embriões desenvolvimento R e L. Não foi detectada 53BP1 em embriões suínos AP durante o desenvolvimento inicial. Embriões do grupo L apresentaram maior quantidade de γH2AX no D-5 quando comparado ao grupo R; entretanto, não houve diferença de marcação para NSB1 e RAD52. Estes dados indicam que o mecanismo de apoptose interfere no desenvolvimento embrionário inicial com efeito positivo do inibidor de caspase, na taxa de blastocisto de embriões suínos AP. Embriões de desenvolvimento L apresentaram um aumento da sinalização às injúrias do DNA, entretanto, a diferenças quanto ao potencial de reparo do DNA lesado em embriões de diferentes potenciais de desenvolvimentos, ainda precisam ser melhor investigadas.Apoptosis is a highly conserved form of cell death that plays a major role in animal development and cellular homeostasis by acting as a quality control mechanism to remove cells that are damaged, nonfunctional, misplaced or supranumerary. This form of cell death plays a major role on preimplantation embryonic development since embryonic cells are often subject to DNA damage, triggering either DNA damage and repair mechanisms or apoptosis. Once initiated the apoptotic process leads to caspase activation and cleavage of cellular substrates. The aim of the present study was to quantify active Caspase-3 (+casp-3) and to determine the role of this pro-apoptotic enzyme on the development of preimplantation porcine embryos, as well as to investigate the presence and localization of DNA damage and repair proteins. Four experiments were conducted using slaughterhouse immature oocytes collected from pre-pubertal gilt ovaries and in vitro matured (IVM) for 44-46 h. Metaphase II (MII) oocytes were parthenogenetically activated (PA) using ionomycin and strontium chloride and cultured in PZM-3 at 38ºC, 5% CO2 in air and high humidity. In the first study embryos were distributed into 4 groups according to cleavage time and cell number: R4 - cleaved at 24 h with ≥4-cells at 48 h; R2 - cleaved at 24 h with 2-3 cells at 48 h; L4 - non-cleaved at 24 h with ≥4-cells at 48 h; L2 - non-cleaved at 24 h with 2-3 cells at 48 h. Group R embryos showed higher blastocyst rates R4-66.1 (174/263) and R2-59.6 (62/104) and more nuclei per blastocyst, R4-40.1 and R2-38.9, when compared to group L L4-15.4 (6/39) and L2-16.8 (13/77); L4-18.5 and L2-18.3 (Chi-square and Tukey-Kramer, P<0.05); however, there were no differences between R4 and R2 or L4 and L2. The second experiment used only early-(R) and late-cleaved embryos (L), classified at 24 h of IVC, fixed at D-2, D-4 and D-6 and then stained for +casp-3 immunofluorescence. In this embryos fixed at D-2, D-4 and D-6 were considered as sub-experiments conducted in different replicates. Active Caspase-3 cytoplasmic signal was detected in cultured embryos from D2 to D6 and nuclear signal was detected from D5 to D6. The relative amount of immunofluorescence signal for +casp-3 for groups R and L at D2, D4 and D6 of culture was 2.4 vs. 1.4; 1.1 vs. 1.0 and 1.1 vs. 1.2, respectively. A third experiment was conducted to evaluate the role of +casp-3 on porcine preimplantation embryos. In this study the Caspase inhibitor Z-DEVD-fmk (100 uM) was supplemented during maturation of porcine oocytes or embryo culture (D0 to D2 or D4 to D6). Addition of the caspase inhibitor during IVM or D4 to D6 of culture did not affect blastocyst rate. However, caspase inhibition from D0 to D2 increased development of porcine embryos to the blastocyst stage [55.1 (59/107) and 37.5 (39/104) for control and Z-DEVD-fmk, respectively; Chi-square, P<0.05). The last experiment investigated the presence of DNA damage and repair proteins γH2AX, 52BP1, NSB1, and Rad52 in early- and late-cleaved embryos by immunofluorescence. There was no 53BP1 signal in PA porcine embryos at beginning of IVC. Late-cleaved embryos showed higher γH2AX signal than early-cleaved embryos; however, there was no difference between NSB1 and Rad52 staining between these embryos. In conclusion, apoptosis and DNA damage and repair mechanisms play a role on development of porcine embryos. Active caspase-3 is present in porcine embryos throughout the preimplantation period and inhibition of this enzyme at early stages of in vitro culture can increase blastocyst rate of PA embryos. Moreover, late-cleaved embryos carry higher DNA damage than early-cleaved embryos. Therefore, the relationship between DNA repair mechanism and developmental potential of porcine embryos need to be further investigated.