Rozprawy doktorskie: „Prophase I”

1

Lee, Chih-ying. "Bouquet formation, rapid prophase movements and homologous pairing during meiotic prophase in Saccharomyces cerevisiae". Oklahoma City : [s.n.], 2009.

Znajdź pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

2

Testori, Sarah. "Cohesin dynamics during meiotic prophase". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/29857.

Pełny tekst źródła

Streszczenie:

For faithful segregation during meiosis, chromosomes must be physically linked by both sister chromatid cohesion (SCC), provided by cohesin, and at least one crossover (CO). In mitosis, cohesin is dynamically associated with chromatin and this has been shown to be crucial for the repair of DSBs. Although DSBs are purposely made to start meiotic recombination, it is unknown if meiotic cohesin is dynamically associated with chromatin. However, cohesin loss or degradation is thought to be involved in the high incidence of aneuploidy observed in human eggs. In Caenorhabditis elegans (C. elegans), the cohesin loader SCC-2 remains associated with the axial element of meiotic chromosomes following the completion of S-phase, hinting that cohesin may be reloaded during meiotic prophase. To confirm this, I investigated if depleting SCC-2 by RNAi after entrance into meiotic prophase had an effect on cohesin association with chromosomes. This revealed loss of the cohesin subunit REC-8 from late prophase nuclei, suggesting that without reloading cohesin is removed from chromatin. Furthermore, scc-2 RNAi also resulted in the impairment of chiasmata, raising the possibility that cohesin reloading plays a role in CO formation or in chiasma maintenance. Two key mediators of cohesin removal are known to operate during the G2 phase of the mitotic cell cycle: the presence of DSBs and the cohesion anti-establishment factor Wapl1. Here I show for the first time that WAPL-1 modulates the cohesiveness of complexes containing the meiosis-specific kleisins COH-3 and COH-4. Furthermore, cohesin complexes containing different kleisins are differentially modulated by DSBs, and only REC-8-containing cohesin complexes can undertake the repair of DNA damage. Finally, I have developed several genetic tools to allow the visualization of cohesin turnover during meiosis. These findings show the exceptional complexity of cohesin dynamics during meiotic prophase, as well as demonstrating roles for cohesin outside of the provision of SCC.

Style APA, Harvard, Vancouver, ISO itp.

3

Ghafari, Fataneh. "Oocyte progression and death during first meiotic prophase". Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409952.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

4

Persico, Angela. "The Role of Golgi Fragmentation in the Regulation f G2/Prophase Transition". Thesis, Open University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520741.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

5

Crawley, Oliver. "Investigating the regulation of cohesin dynamics during meiotic prophase in C. elegans". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/44281.

Pełny tekst źródła

Streszczenie:

The physical linking of sister chromatids after S-phase is known as sister chromatid cohesion (SCC) and is largely provided by the cohesin complex. The coordinated loss of SCC at anaphase onset is essential for correct chromosome segregation, a process mediated by proteolysis of the kleisin subunit of cohesin. In addition, during mitotic prophase of most organisms a large portion of cohesin is removed from chromosomes by a non-proteolytic pathway that depends on the conserved protein WAPL. Cohesin is also known to reload and SCC is re-established in response to DSBs after mitotic S-phase. During meiosis, SCC is similarly established during S-phase, but is then released in two steps during the sequential meiotic divisions. Also, unlike mitosis, multiple cohesin complexes with divergent functions exist in meiosis. Whether cohesin is dynamically associated with chromosomes during meiotic prophase and how this may be regulated was not known. Thus, the key aims of this project were to determine if WAPL mediates cohesin removal during meiotic prophase, and to find out if meiotic cohesin complexes display turnover on prophase chromosomes of the nematode C. elegans. Alternative meiosis-specific kleisins (REC-8, COH-3, and COH-4) define the different complexes present during worm meiosis. I show here that WAPL-1 limits the association of COH-3/4 complexes with meiotic prophase chromosomes, which severely limits their cohesive function. REC-8 complexes on the other hand are not affected much by WAPL-1. I show that loss of WAPL-1 affects the structure of axial elements and disrupts chromosome segregation and DSB repair. I also demonstrate by FRAP live imaging that there is significant turnover of cohesin on meiotic prophase chromosomes. Dynamic turnover of COH-3 is much greater that REC-8, as predicted by the different sensitivity to WAPL-1 of REC-8 and COH-3 cohesin complexes. These findings demonstrate that cohesin is actively removed and reloaded during meiotic prophase. Dysregulation of these processes could be relevant for human fertility, since SCC exhaustion over time is thought to contribute to the decline in fertility with increased maternal age.

Style APA, Harvard, Vancouver, ISO itp.

6

Ene, Adriana. "Meiotic prophase progression and germ cell elimination in fetal and neonatal mouse ovaries". Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92367.

Pełny tekst źródła

Streszczenie:

In most mammalian species, all oogonia cease mitotic proliferation and enter meiosis in fetal ovaries. Furthermore, more than half of the maximum number of germ cells is eliminated from ovaries by neonatal life, thus limiting the oocyte reserve for reproduction. The cause or mechanism of this female germ cell loss remains largely unknown. A major loss occurs in the oocytes which reach the pachytene stage of meiotic prophase, suggesting that oocytes with meiotic or recombination errors may be eliminated by a checkpoint mechanism. It remains to be determined whether oocytes are eliminated by apoptosis and if so in which pathway. The purpose of my study is to investigate a mechanism of oocyte loss in the mouse ovary during meiotic prophase. We used an Msh5 null mutant mouse strain, in which all oocytes are eliminated by neonatal life. Msh5 encodes a protein required for meiotic chromosome synapsis.
Msh5 heterozygous mutant mice were crossed and ovaries were isolated from female progeny at 14.5 22.5 days postcoitum (dpc). We studied the loss of germ cells in Msh5 -/- (MT) females comparing to the Msh5 +/+ (WT) and Msh5 (+/-) (HT) females by immunolabeling of ovarian sections for GCNA1 or MVH (both germ cell markers) or by counting GCNA1 positive germ cells in cell suspension preparations. Our results showed a continuous loss of GCNA1 positive cells in both MT and WT although the loss in MT was constantly larger than in the WT. A significant difference between WT and MT was found at 19.5 dpc.
Meiotic progression was studied by GCNA1 and SC (synaptonemal complex) or SC and ɣH2AX double immunolabeling of chromosome spread preparations. We found that meiosis in MT was blocked at zygotene-pachytene transition. No normal pachytene was observed in MT.
The role of apoptosis in elimination of oocytes during meiotic prophase was investigated by analyzing the cleavage of various caspases (caspase 2, 3, 6, 7, 9) as well as PARP1 by western blot using the lysate of whole ovaries. The activation of initiator caspase 9 increased from 17.5 to 18.5 dpc and decreased by 19.5 dpc. Caspase 2L activation also increased in a similar pattern but at much lower levels. The activation of effector caspase 3 or 6 remained at low levels. The activation of caspase 7 also was low but increased slightly at 19.5 dpc. The cleavage of PARP1 was high at all investigated stages. There were not major differences in the average level of activation between WT and MT. By immunolabeling of ovarian sections we observed that cleaved caspases and PARP1 were localized in oocytes but also in cells negative for GCNA1.
These results suggest that a mitochondrial pathway of apoptosis may play a role in the elimination of oocytes during meiotic prophase, involving activation of caspase 9 and cleavage of PARP1. However further studies are necessary for identification of an effector caspase.
Dans la plupart des espèces de mammifères, tous les oocytes cessent la prolifération mitotique et initialisent la méiose dans les ovaires ftales. En outre, plus de la moitié du nombre maximal de cellules germinales est éliminée dans les ovaires pendant la vie néonatale, limitant ainsi la réserve d'oocytes pour la reproduction. La cause ou le mécanisme de cette perte de cellules germinales femelles reste largement inconnu. Une perte majeure se produit dans les oocytes qui atteignent le stade pachytène de la prophase méiotique, suggérant que les oocytes avec des erreurs dans la méiose ou des erreurs de recombinaison peuvent être éliminés par un mécanisme de contrôle. Il reste à déterminer si les oocytes sont éliminés par apoptose, et si oui, par quel méchanisme. Le but de mon projet est d'étudier un mécanisme de perte d'oocytes dans les ovaires de souris durant la prophase méiotique. Nous avons utilisé une souche de souris mutantes pour la gene Msh5, dans lequelles tous les oocytes sont éliminés durant la vie néonatale. Msh5 code pour une protéine nécessaire à la synapse de chromosomes méiotiques.
Des souris hétérozygote Msh5 ont été croisées et les ovaires ont été isolées de la progéniture féminine de 14,5 à 22,5 dpc. Nous avons étudié la perte de cellules germinales dans les ovaires des femelles Msh5 -/- (MT) en les comparant à ceux des femelles Msh5 +/+ (WT) et Msh5 +/- (HT) par immunodétection en utilisant des anticorps anti-GCNA1 et anti-MVH (marqueurs des cellules germinales) ou par le comptage des cellules positives au GCNA1 dans des suspensions cellulaires. Nos résultats montrent une perte continue de cellules positives au GCNA1 chez les souris MT et WT, bien que la perte chez les MT a été constamment supérieure à celle des WT (différence significative à 19.5 dpc).
La progression de la méiose a été étudiée par immunodétection double pour GCNA1 et SC (complexe synaptonémal) ou pour SC et γH2AX sur des préparations de chromosomes. Nous avons constaté que la méiose chez les souris MT est bloquée dans le stage de transition zygotène-pachytène. Nous n'avons pas observé de pachytène normal chez les souris MT.
Le rôle de l'apoptose dans l'élimination d'oocytes au cours de la prophase méiotique a été étudié par analyse du clivage de diverses caspases (caspases 2, 3, 6, 7, 9) ainsi que celui de la PARP1 par immunobuvardage des protéines d'ovaires entières lysées. L'activation de la caspase 9 initiatrice a augmenté entre 17.5dpc et 18.5 dpc et a ensuite baissé à 19.5 dpc. Celle de la caspase 2L a augmenté d'une manière semblable, mais à des niveaux beaucoup plus bas. L'activation des caspases effectrice 3 et 6 est demeurée à des niveaux faibles mais celle de la caspase 7 bien que faible a augmenté légèrement à 19.5 dpc. Le clivage de PARP1 était élevé dans tous les stages. Dans tous ces cas, il n'y a pas eu de grandes différences dans le niveau moyen d'activation entre WT et MT. Par immunodétection de sections d'ovaires, nous avons observé que les caspases et PARP1 clivées étaient localisées dans des oocytes, mais aussi dans les cellules sans marquage pour GCNA1.
Ces résultats indiquent que la voie mitochondriale de l'apoptose peut jouer un rôle dans l'élimination d'oocytes au cours de la prophase méiotique, puisque les clivages de la caspase 9 et de PARP1 y sont associés. Cependant des études supplémentaires sont nécessaires pour l'identification de caspases effectrices.

Style APA, Harvard, Vancouver, ISO itp.

7

Loh, Benjamin Jia Hui. "Novel screens to identify genes regulating global chromatin structure during female meiotic prophase". Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4613.

Pełny tekst źródła

Streszczenie:

During female meiotic prophase in many organisms, a specialized chromatin structure is formed in the oocyte nucleus. This structure is known as the karyosome, and has been proposed to be important for the formation of the female meiotic bipolar spindle. However, how the karyosome is formed and maintained is not very well understood. To identify proteins involved in the formation and maintenance of the karyosome, I carried out a cytological screen on a collection of 220 mutant fly lines for mutants that were defective in karyosome morphology. The screen identified 46 mutants on the X and 2nd chromosome with abnormal karyosomes. Genetic analysis of these 46 mutants, followed by molecular analysis of one mutant, identified SRPK (SR Protein Kinase) as a protein that is important for the proper formation of the karyosome. NHK-1 (Nucleosomal Histone Kinase 1) was previously identified as a protein that is essential for the formation of the karyosome via its phosphorylation of BAF (Barrier-to-Autointegration Factor). NHK-1 phosphorylation of BAF leads to the release of chromatin from the nuclear membrane, an essential step for the formation of the karyosome, however, the regulation of this process is unclear. In order to identify genes that interact with NHK-1, I carried out a genetic modifier screen using a semi-lethal allele of NHK-1, NHK-1trip. After screening a collection of 44 deficiencies located on the 2nd chromosome, I identified a genetic region (44B8-44D1) containing a gene that interacts with NHK-1 and, when gene dosage is halved, enhanced the semi-lethal phenotype of NHK-1trip.

Style APA, Harvard, Vancouver, ISO itp.

8

Hanafi, Jasmin. "Identifying factors involved in chromosome movement during prophase I of meiosis in Caenorhabditis elegans". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121248.

Pełny tekst źródła

Streszczenie:

Meiosis is a reductional cell division that produces haploid gametes and uniquely allows the introduction of genetic diversity via crossover recombination between homologous chromosomes. Any defect during this process could lead to the non disjunction of chromosomes, which in turn leads to aneuploidy in the resulting progeny, a condition that is generally lethal but in certain cases results in serious developmental abnormality. In C. elegans, at the onset of meiosis, chromosomes condense and cis-acting regions near each chromosome end called pairing centers recruit zinc-finger proteins which help chromosomes associate with nuclear envelope bridge proteins. These bridge proteins are in turn linked to the cytoskeleton network. This association is important to facilitate chromosome clustering and homology search. Once chromosomes are properly homologously paired, the process of division continues until eventually four haploid cells are produced. Though the successful coordination and regulation of each step in meiosis is critical for the survival of a species, many components of the process remain unclear. During prophase I, chromosome movement resulting in proper homologous pairing is controlled and regulated in a manner that is not well understood. The objective of my research therefore, is to try and identify factors involved in this chromosome movement. To do this, a candidate RNAi screen of 482 genes was conducted and 156 genes were positively identified as having a lack of chromosome movement. Since any mistakes in pairing and subsequent stabilization of homologous chromosomes could lead to non disjunction and possible embryonic lethality (emb) from loss of an autosome or a high incidence of males (him) from loss of the X chromosome, positive candidates were also screened for emb and him. Of the 156 positive candidates, 24 were also positive for emb and 1 was additionally positive for him. These candidates present many possibilities for further validation and characterization in future projects.
La méiose est une division cellulaire réductionnelle qui produit des gamètes haploïdes et permet d'une façon unique l'introduction de diversité génétique à travers la recombinaison entre les chromosomes homologues. Tout problème dans le processus peut causer une impossibilité de séparation entre les chromosomes, ce qui à son tour cause l'aneuploïdie dans la génération suivante, une condition qui est généralement mortelle, mais résulte en anomalie dans le développement dans certains cas. Les chromosomes de C. elegans, au tout début de la méiose, se condensent et les régions "cis" à la fin de chaque chromosome appelées centres paires recrutent les protéines avec des doigts de zinc qui aident les chromosomes associer avec le pont de protéines sur l'enveloppe nucléaire. Le pont est connecté au réseau cytosquelette. Cette association est importante pour la facilitation du regroupement des chromosomes et la recherche de chromosomes homologues. À la retrouvaille des chromosomes homologues, le processus de division continue jusqu'à ce que quatre cellules haploïdes soient produites. Même si le succès de la coordination de chaque étape de la méiose est critique pour la survie des espèces, certain détails du processus restent inconnus.Durant la prophase I, le mouvement des chromosomes qui résulte dans le propre couplement des chromosomes homologues est contrôlé et régulé d'une manière encore inconnue. L'objectif de mes recherches est donc d'identifier des facteurs associés dans ledit mouvement des chromosomes. Pour accomplir ce but un écran de ARNi avec 482 gènes comme candidates a été mené et 156 gènes ont été positivement identifiés pour une manque de mouvement des chromosomes. Comme tout problème de formation des couples de chromosomes ainsi que dans la stabilisation des chromosomes homologues qui suit peut causer de la non-disjonction et possible mort embryonnaire (emb) suite à la perte d'un autosome ou une haute incidence de males (him) causé par la perte du chromosome X, les candidats out aussi été examinés pour emb et him. Des 156 candidats positifs, 24 ont aussi été positifs pour emb et un candidat a été additionnellement positif pour him. Ces candidats se présentent comme une source de futures recherches de validation ainsi que de caractérisation.

Style APA, Harvard, Vancouver, ISO itp.

9

Guichaoua, Marie-Roberte. "L'infertilité masculine d'origine chromosomique : ses mécanismes : apport de l'étude du stade pachytène dans les spermatocytes I en prophase de Méiose". Aix-Marseille 2, 1990. http://www.theses.fr/1990AIX21904.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

10

Pyatnitskaya, Alexandra. "Interplay between meiotic crossing-overs and chromosome architecture : role of the meiosis specific complex Zip2-Zip4-Spo16". Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLS061.

Pełny tekst źródła

Streszczenie:

La méiose est une étape essentielle de la reproduction chez tous les organismes sexués. En effet, celle-ci permet l’obtention de quatre gamètes haploïdes à partir d’une seule cellule diploïde grâce à la réalisation deux divisions successives suivant une seule étape de réplication. Un des éléments essentiels permettant une bonne ségrégation en première division méiotique est la création d’un échange physique entre les chromosomes homologues parentaux. Ce lien physique, plus communément appelé crossing-over (CO), est produit par un mécanisme de recombinaison entre les chromosomes homologues au cours de la prophase I méiotique. La recombinaison homologue est initiée par la formation simultanée de nombreuses cassures double-brin au sein du génome. Chez la levure de boulanger, la formation des COs est dépendante de la famille protéique ZMM (un acronyme pour Zip1/2/3/4-Msh4/5-Mer3-Spo16) composée de huit protéines hautement conservées, et impliquées dans la reconnaissance et la stabilisation des intermédiaires d’ADN formés au cours de la recombinaison homologue. Nous avons montré que la protéine Zip4 forme un complexe stable avec deux autres protéines ZMM, Zip2 et Spo16. Le complexe Zip2-Zip4-Spo16 (ZZS), de type XPF-ERCC1, serait capable de reconnaitre et de stabiliser les intermédiaires de recombinaison afin de promouvoir leur réparation en tant que CO. Chez les mammifères, Zip2 et Zip4 possèdent des homologues décrits, SHOC1 et TEX11 respectivement, mais aucun homologue n’a été découvert pour Spo16. Nous avons réalisé une analyse in silico et pu déterminer un homologue de Spo16 chez les mammifères, MmSPO16. Par la suite, j’ai pu co-purifier MmSPO16 avec le domaine XPF de SHOC1, ce qui suggère la conservation du complexe ZZS chez les mammifères. De plus, le processus de formation des COs est corrélé́ à la mise en place d’un complexe protéique formé entre les deux chromosomes homologues, appelé complexe synaptonémal (CS). Le CS est composé de deux éléments axiaux, accolés entre eux à une distance précise de 100 nm par la région centrale. La région centrale comprend un élément central, composé de l’hétérodimère Ecm11-Gmc2, et d’un élément transversal formé par la protéine Zip1. Les éléments transversaux partant des axes opposés se lient tête-bêche au niveau de l’élément central. Malgré des liens fonctionnels évidents entre la formation des COs et l’assemblage du CS entre les chromosomes homologues, aucun lien physique direct n’a été établi à ce jour. Au cours de mon doctorat, j’ai pu démontrer l’existence d’une interaction physique entre la protéine du CS Ecm11 et la protéine ZMM Zip4. Cette interaction est nécessaire pour la localisation et la polymérisation d’Ecm11 sur les chromosomes, l’assemblage correct du CS et la ségrégation des chromosomes homologues en première division méiotique
Meiosis is a highly conserved mechanism among organisms with sexual development. This process consists in producing four haploid gametes from one diploid cell by executing two successive rounds of cell division. During the first meiotic division, reciprocal exchanges of parental DNA strands, also known as crossing-overs (COs), ensure the faithful segregation of homologous chromosomes. COs arise from a specific type of DNA repair, homologous recombination. This pathway is initiated by the simultaneous induction of hundreds of double strand breaks (DSBs) in the genome. In budding yeast, the major CO pathway is promoted by a family of eight conserved proteins, named ZMMs (acronym for Zip1/2/3/4-Msh4/5-Mer3-Spo16), involved in recognizing and stabilizing DNA intermediates formed during homologous recombination. We showed that the Zip4 protein forms a stable tripartite complex with two other ZMM proteins, Zip2 and Spo16. Our data suggests that the Zip2-Zip4-Spo16 (ZZS) complex binds recombination intermediates through its XPF-ERCC1-like domain and drives them towards a CO fate. The homologs of Zip2 and Zip4 in mammals, SHOC1 and TEX11 respectively, have been described, but no Spo16 homolog has been found so far. We could identify the homolog of Spo16 in mammals by an in silico screen, MmSPO16. In addition, I could co-purify MmSPO16 with the XPF domain of SHOC1, thus revealing the potential conservation of the entire ZZS complex in mammals. ZMM-dependent COs are formed within the context of a meiosis-specific structure, named synaptonemal complex (SC). The SC is a proteinaceous structure composed of two axial elements physically maintained together at a precise distance of 100 nm by a central region. The central region encompasses a central element, composed of the two proteins Ecm11 and Gmc2, and the transverse filaments composed of Zip1. The transverse filaments from opposing axial elements overlap and bind head-to-head in the central element. However, despite evidence of a close relationship between SC assembly and CO formation, nothing is known about a direct link that could coordinate these two events spatially and temporally. During my PhD, I found a new interaction between the SC protein Ecm11 and the ZMM protein Zip4. This newly discovered interaction is necessary for Ecm11 association and polymerization on chromosomes, the SC assembly and the homolog disjunction in meiosis I. Our results suggest a direct connection that ensures SC assembly from CO sites through the Zip4-Ecm11 interaction. This way, ensuring SC polymerization from emerging CO sites could be a way of fine-tuning CO distribution, by participating to CO interference and/or by regulating nearby DSB formation. Moreover, I could identify an interaction between the mammalian ortholog of Zip4, TEX11, and one of the five members composing the SC central element, TEX12, raising the possibility that this mechanism synchronizing CO formation and SC polymerization could be conserved

Style APA, Harvard, Vancouver, ISO itp.

11

Fazio, Cynthia Marie. "The influence of meiotic onset on and the role of apoptosis in oocyte death during the meiotic prophase /". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97951.

Pełny tekst źródła

Streszczenie:

Loss of germ cells that entered meiosis at different developmental stages was compared. Mice were injected with BrdU at 13.3, 14.3 or 15.3 days post coitum (dpc) and sacrificed either 3 days after BrdU injection or 4 days post partum (dpp). BrdU-labeled germ cells were detected in ovarian sections through double immunofluorescent staining for BrdU and either GCNA-1 or MVH as a germ cell marker. The results show that the loss of germ cells that entered meiosis at 13.3 or 15.3 dpc was excessive compared to the loss of total germ cells. Such preferential elimination was not found for germ cells that entered meiosis at 14.3 dpc. We conclude that oocyte loss during meiotic prophase is influenced by the timing of meiotic onset.
The mechanism of germ cell loss during ovarian development was tested by the presence of markers for apoptosis. Mouse ovaries were isolated at 12.5 dpc, 18.5 dpc and 2 dpp and cultured with doxorubicin (DXR) to induce cell death. Ovarian histological sections were double immunofluorescent stained for GCNA-1 and cleaved caspase-3 or PARP-1. The results suggest that caspase-3 is not activated in germ cells throughout ovarian development whereas PARP-1 is activated in germ cells at 12.5 dpc and 2 dpp but not at 18.5 dpc. Thus, no evidence has yet been provided to support the hypothesis that oocyte death during the meiotic prophase is mediated by apooptosis.

Style APA, Harvard, Vancouver, ISO itp.

12

Zhaunova, Liudmila. "Regulation of oocyte-specific chromatin organisation during prophase I by the histone demethylase Kdm5/Lid and other proteins". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29007.

Pełny tekst źródła

Streszczenie:

In Drosophila oocytes, chromosomes undergo dynamic reorganisation during the prophase of the first meiotic division. This is essential to prepare chromatin for synapsis, recombination and consequent chromosome segregation. The progression of meiotic prophase I is well described, while the molecular mechanisms and regulation of these dramatic chromosomal reorganisations are not well understood. Histone modifying enzymes are major regulators of chromatin structure, however, our knowledge of their roles in meiotic prophase I is still limited. In this work, I investigated the role of the histone demethylase Kdm5/Lid, which removes one of the trimethyl groups at Lys4 of Histone 3 (H3K4me3). I showed that Kdm5/Lid is important for the assembly of the synaptonemal complex, pairing of homologous centromeres, and the karyosome formation. Additionally, Kdm5/Lid promotes crossing over and therefore ensures accurate chromosome segregation. Although loss of Kdm5/Lid dramatically increased the level of H3K4me3 in oocytes, catalytically inactive Kdm5/Lid rescued the above cytological defects. Thereby, I found that Kdm5/Lid regulates chromatin architecture in meiotic prophase I oocytes independently of its demethylase activity. To further identify the regulators of meiotic chromatin organisation during prophase I, I carried out a small-scale RNAi screen for karyosome defects. I found that depletion of ubiquitin ligase components, SkpA, Cul-3 and Ubc-6, disrupted the karyosome formation and the assembly of the synaptonemal complex. The success of the small-scale screen motivated me to initiate the genome-scale RNAi screen for karyosome defects. I found 40 new genes that, when depleted, strongly impaired karyosome morphology. Further studies are required to confirm and elucidate their role in chromatin organisation in oocytes. Overall, my findings have advanced our understanding of the regulation of chromatin reorganisation during oocyte development. Because of the conservation between Drosophila and human meiosis, this study provides novel insights into the regulation of meiotic progression in human oocytes.

Style APA, Harvard, Vancouver, ISO itp.

13

De, Kuntal. "ARABIDOPSIS WAPL IS ESSENTIAL FOR THE PROPHASE REMOVAL OF COHESIN DURING MEIOSIS AND ANTAGONIZES THE ROLE OF CTF7". Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1402059889.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Park, Stephanie. "The caspase 9-dependent apoptotic pathway is essential for oocyte loss during meiotic prophase progression in the mouse ovary". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116959.

Pełny tekst źródła

Streszczenie:

Female reproduction is limited by the oocyte pool, which establishes soon after birth in the mouse. It is dogma that more than half of the initial oocyte population is eliminated during the first meiotic prophase progression in fetal life. Apoptosis has been proposed as a mechanism for this oocyte loss; however, its pathway remains to be clarified. The mitochondrial apoptotic pathway is mediated by initiator caspase 9, which in turn activates effector caspase 3, 6, or 7 leading to cell death. The purpose of my study is to investigate the role of caspase 9 in the loss of oocytes during meiotic prophase progression. We first examined the activation of various caspases by immunofluorescence (IF) staining of cleaved caspases in ovarian sections. The results showed that both caspase 9 and 7 were constitutively activated in oocytes in the meiotic prophase. We then examined Casp9 deficient mice. Casp9 +/- mutants were crossed and ovaries were isolated from female progeny at 16.5-19.5 days postcoitum (dpc). The ratio of Casp9 -/- females drastically decreased during this period, confirming the perinatal lethality of caspase 9 deficiency. The total number of germ cells, identified by IF staining of GCNA1, in dissociated cells of Casp -/- ovaries were comparable to those in control ovaries at 16.5 dpc but became twice as large than those in +/+ or +/- ovaries at 19.5 dpc. Meiotic prophase progression, assessed by IF staining of synaptonemal complex components, was similar in all genotypes. IF staining of GCNA1 and γH2AX, a marker of double strand breaks, showed that the excessive numbers of oocytes were accumulated at the end of meiotic prophase in the Casp -/- ovary. Our results suggest that caspase 9 plays an essential role leading to oocyte loss and a block of caspase 9 dependent apoptotic pathway allows for a greater number of oocytes to survive and progress through the meiotic prophase
La reproduction chez les femelles est limitée par le pool d'ovocytes qui est établi peu après la naissance chez la souris. Il est considéré comme un dogme que la moitié de la population initiale d'ovocytes est éliminée durant la vie fœtale pendant la première progression de la prophase méiotique. L'apoptose a été proposée comme mécanisme expliquant la perte de ces ovocytes, mais ceci reste à être clarifié. La voie apoptotique mitochondriale est médiée par la caspase 9 initiatrice, qui active à son tour les caspases effectrices 3, 6 ou 7, amenant à la mort cellulaire. Le but du projet était d'étudier le rôle de la caspase 9 dans la perte des ovocytes pendant la progression de la prophase méiotique. Premièrement, nous avons étudié par immunofluorescence (IF) l'activation de différentes caspases en marquant des caspases clivées dans des sections de tissus ovariens. Les résultats ont montré que les caspases 9 et 7 sont activées de manière constitutive dans les ovocytes durant la prophase méiotique. Par la suite, nous avons étudié des souris déficientes pour Casp9. Des souris mutantes Casp9 +/- ont été croisées, puis les ovaires des femelles de la progéniture ont été isolés aux jours 16,5-19,5 post-coïtum. Le ratio de femelles Casp9 -/- a drastiquement diminué pendant cette période, confirmant la mortalité périnatale lorsqu'il y a une déficience de caspase 9. Le nombre total de cellules germinales dans des cellules dissociées d'ovaires de souris Casp9 -/-, identifiées par IF en marquant GCNA1, était comparable au contrôle des ovaires au jour 16,5 post- coïtum mais a augmenté deux fois chez les ovaires de souris +/+ ou +/- au jour 19.5 post-coïtum. La progression de la prophase méiotique, telle qu'observée par IF en marquant les composantes de complexe synaptonemale, était similaire dans tous les génotypes. Le marquage par IF de GCNA1 et H2AX, un marqueur de bris doubles brins de l'ADN, a démontré que le nombre excessif d'ovocytes est accumulé à la fin de la prophase méiotique dans les ovaires des souris -/-.Nos résultats suggèrent que la caspase 9 joue un rôle essentiel amenant à la perte des ovocytes et le blocage de la voie apoptotique dépendante à la caspase 9 permet la survie d'un nombre plus important d'ovocytes qui progresseront dans la prophase méiotique I.

Style APA, Harvard, Vancouver, ISO itp.

15

Bellutti, Laura. "Régulation transcriptionnelle et entrée en méiose". Thesis, Université de Paris (2019-....), 2019. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=4244&f=28602.

Pełny tekst źródła

Streszczenie:

La méiose est un processus hautement conservé, central dans la reproduction sexuée, permettant la production de cellules haploïdes à partir des cellules germinales diploïdes. Chez les mammifères l’entrée en méiose est étroitement régulée et dépendante du sexe : elle a lieu au cours de la vie fœtale chez la femelle et pendant la vie post-natale chez le mâle. À l’heure actuelle, l’acide rétinoïque (AR) est considéré comme le principal régulateur de l’entrée en méiose : il induirait l’expression de Stra8 (Stimulated by the retinoic acid gene 8), facteur transcriptionnel clé de la transition mitose/méiose. Dans les testicules fœtaux, CYP26B1, enzyme capable de cataboliser l’AR, inhibe l’expression de Stra8 et l’entrée en méiose. Cependant, il n’existe pas de preuve définitive du rôle de l’AR endogène dans l’initiation de la méiose. Nous avons donc tenté de clarifier l’implication de l’AR dans la régulation de Stra8 en vie fœtale. Pour cela nous avons développé une méthode de surexpression ex vivo des enzymes CYP26B1 et CYP26A1, une autre enzyme avec une activité catalytique de l’AR. Nous montrons que CYP26B1 est suffisant pour inhiber STRA8 dans l’ovaire fœtal, indépendamment de la voie de signalisation de l’AR. Nous proposons ainsi que l’AR agisse dans l’amplification de Stra8 plutôt que dans son induction primaire. Récemment deux autres facteurs ont été caractérisés pour leur rôle clé dans la régulation de la transition mitose/méiose au niveau post-transcriptionnel : MEIOC et son partenaire YTHDC2. Nous avons effectué une analyse des mutants Stra8, Meioc et Ythdc2, qui révèlent de nombreuses similarités. Nous émettons donc l’hypothèse de l’existence d’un continuum entre la régulation transcriptionnelle (par STRA8) et post-transcriptionnelle (par MEIOC/YTHDC2) en début de méiose. En outre, la double-invalidation de Stra8 et Meioc ne prévient pas l’entrée en méiose de quelques rares spermatocytes. Nous suggérons donc l’existence de facteurs additionnels, encore à découvrir, contrôlant la transition mitose/méiose.Enfin, nous montrons qu’au moment de la transition mitose/méiose les spermatocytes I sont trancriptionnellement silencieux. Cette répression transcriptionnelle est en partie régulée par Stra8 mais elle est indépendante des évènements clés de la prophase I : cassures double brin, synapsis des chromosomes homologues, changements de la structure chromatinienne. En exploitant une méthode de synchronisation de la spermatogenèse et en immunoprécipitant les ARN néotranscrits, nous avons alors caractérisé le paysage de la transcription en début de méiose pour la première fois. Nous mettons ainsi en évidence des évènements de stabilisation/déstabilisation des ARN ayant lieu au cours de la prophase I. Ces travaux ont donc mis en lumière le haut degré de complexité caractérisant l’entrée en méiose des cellules germinales. Cette dernière est régulée par plusieurs facteurs, dont certains demeurent encore inconnus, aux niveaux transcriptionnel et post-transcriptionnel
Meiosis is a conserved process, allowing the production of haploid germ cells. In mammals, entry into meiosis is sexually dichotomic, taking place during fetal life in ovaries and during postnatal life in testes. In fetal ovaries, Retinoic Acid (RA) is believed to activate Stra8 (Stimulated by the retinoic acid gene 8), a key factor of mitosis/meiosis transition. In fetal testes, CYP26B1, a RA-metabolising enzyme, prevents Stra8 expression. However, the exact role of endogenous RA remains uncertain.The first objective of my work was to clarify the function of endogenous RA in meiotic initiation. For this purpose, we created a model of artificial RA deficiency by ex vivo electroporation of fetal gonads with plasmids encoding Cyp26b1 or Cyp26a1, two RA-metabolising enzymes. We observed that ectopic CYP26B1 is sufficient to prevent STRA8 appearance in germ cells from fetal ovaries. In contrast, overexpression of CYP26A1 only mildly affects the expression of Stra8 mRNA. We thus conclude that CYP26B1 acts independently of RA signalling pathway on meiotic initiation. We propose a two-step model with first a RA-independent Stra8 induction, followed by its RA-dependent amplification.Recently, MEIOC and YTHDC2 have been caracterised as key post-transcriptional regulators of mitosis/meiosis transition. Here, we compare the phenotypes of Stra8, Meioc and Ythdc2 mutant mice Their high similarity prompt us to hypothesise a continuity between transcriptional and post-transcriptional regulations. In parallel, we show that double invalidation of Stra8 and Meioc does not completely prevent meiotic initiation. Thus, we hypothesise the existence of other unknown mitosis/meiosis regulators.Finally, we characterised a genome wide arrest of transcription taking place during mitosis/meiosis transition. This transcriptional silencing is partly dependent of Stra8 but is independent of other key events of meiotic prophase I: double-strand breaks, homologous chromosome synapsis, axe-loop chromosome structure. We took advantage of a spermatogenesis synchronisation protocol and nascent RNA immunoprecipitation, to characterise the transcriptional landscape of early-meiotic germ cells. This highlighted stabilization and destabilization phemomena taking place during prophase I. As a whole, we show the high complexity level of meiosis initiation, which has to be finely regulated by the orchestration of transcriptional and post-transcriptional events

Style APA, Harvard, Vancouver, ISO itp.

16

Aquino, Perez Gildardo. "Generation of an integrated karyotype of the honey bee (Apis mellifera L.) by banding pattern and fluorescent in situ hybridization". [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2416.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

17

Reini, K. (Kaarina). "Characterisation of the human DNA damage response and replication protein Topoisomerase IIβ Binding Protein 1 (TopBP1)". Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514282787.

Pełny tekst źródła

Streszczenie:

Abstract Genetic information is stored in the base sequence of DNA. As DNA is often damaged by radiation or reactive chemicals, cells have developed mechanisms to correct the DNA lesions. These mechanisms involve recognition of damage, DNA repair and cell cycle delay until DNA is restored. Failures in the proper processing of DNA lesions may lead to mutations, premature aging, or diseases such as cancer. In this thesis study the human topoisomerase IIβ binding protein 1 (TopBP1) was identified as the homolog of budding yeast Dpb11 and fission yeast Cut5. TopBP1 was found to be necessary for DNA replication and to associate with replicative DNA polymerase ε. TopBP1 localised to the sites of DNA damage and stalled replication forks, which suggests a role in the DNA damage response. TopBP1 interacted with the checkpoint protein Rad9, which is a part of a protein complex whose function includes tethering proteins to sites of DNA damage. This supports a role for TopBP1 in the early steps of checkpoint activation after DNA damage. TopBP1 also interacted with the tumour suppressor protein p53 in a phosphorylation dependent manner. In addition, the data support a role for TopBP1 outside of S-phase. During M-phase, TopBP1 was found to localise to centrosomes along with the tumour suppressor proteins Brca1 and p53. Analysis of the expression of TopBP1 in mouse tissues suggested that TopBP1 may also play a role during meiosis. The localisation pattern of TopBP1 in mouse meiotic spermatocytes resembled that of many proteins functioning during meiotic recombination. For example, co-localisation of ATR kinase and TopBP1 was observed during meiotic prophase I. In accordance with the findings from mouse studies, the analysis of a cut5 mutant during yeast meiosis showed that Cut5 is essential for the meiotic checkpoint. These results strongly suggest that TopBP1 operates in replication and has checkpoint functions during both the mitotic and meiotic cell cycles.

Style APA, Harvard, Vancouver, ISO itp.

18

Little, Brent Ashley. "Genetic Analysis of Development and Behavior in Hypoxia and Cellular Characterization of Anoxia Induced Meiotic Prophase Arrest in Caenorhabditis Elegans". Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc84241/.

Pełny tekst źródła

Streszczenie:

It was hypothesized that chronic hypoxia will affect various biological processes including developmental trajectory and behavior. To test this hypothesis, embryos were raised to adulthood in severe hypoxic environments (0.5% O2 or 1% O2, 22°C) and analyzed for survival rate, developmental progression, and altered behaviors. Wildtype hermaphrodites survive chronic hypoxia yet developmental trajectory is slowed. The hermaphrodites raised in chronic hypoxia had different phenotypes in comparison to the normoxic controls. First, hermaphrodites exposed to chronic hypoxia produced a significantly lower number of embryos and had a slight increase in male progeny. This suggests that chronic hypoxia exposure during development affects the germline. Second, animals raised in chronic hypoxia from embryos to young adults have a slight increase in lifespan when re-exposed to a normoxic environment, indicating that chronic hypoxia does not negatively decrease lifespan. Finally, hermaphrodites that were raised in hypoxia will lay the majority of their eggs on the area of the agar plate where the bacterial lawn is not present. This is in contrast to animals in normoxia, which lay the majority of their eggs on the bacterial lawn. One hypothesis for this hypoxia-induced egg-laying behavior is that the animal can sense microenvironments in hypoxia. To examine if various pathways are involved with chronic-hypoxia responses RNAi and assayed genetic mutants were used. Specifically, genetic mutations affecting oxygen sensing (egl-9), aerotaxis (npr-1), TFG-ß signaling (dbl-1, daf-7) and predicted oxygen-binding proteins (globin-like genes) were phenotypically analyzed. Results indicate that mutations in several of these genes (npr-1, dbl-1) resulted in a decrease in hypoxia survival rate. A mutation in egl-9 also had a detrimental affect on the viability of an animal raised in chronic hypoxia. However, a similar phenotype was not observed in the vhl-1 mutation indicating that the phenotype may not be due to a mere increase in HIF-1 levels, per se. A mutation in the globin-like gene (glb-13(tm2825)) suppressed the hypoxia-induced egg-laying phenotype. That is, the glb-13(tm2825) animal raised in chronic hypoxia laid eggs on the bacterial lawn at a significantly higher rate in comparison to wildtype controls, thus suggesting that globin-like molecules may be involved with the sensing of microenvironments. Together, this research lays the foundation for understanding the implications of chronic hypoxia in developing organisms.

Style APA, Harvard, Vancouver, ISO itp.

19

Raina, Vivek B. [Verfasser], i Andrea [Akademischer Betreuer] Musacchio. "Regulation of meiotic prophase checkpoint function by the AAA+ ATPase Pch2 and the HORMA protein Hop1 / Vivek B. Raina ; Betreuer: Andrea Musacchio". Duisburg, 2020. http://d-nb.info/122290876X/34.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

20

Soh, Ying Qi Shirleen. "The genomic and genetic basis of mammalian sexual reproduction : sequence of the mouse Y chromosome, and a gene regulatory program for meiotic prophase". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98632.

Pełny tekst źródła

Streszczenie:

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Mammalian sexual reproduction requires sexual determination, sexual differentiation, and the production of haploid gametes. In this thesis, I examined the genomic evolution of the mouse Y chromosome, which instructs sexual determination, and genetic regulation of a program of gene expression for meiosis, a specialized cell cycle which gives rise to haploid gametes. Chapter 2 describes the study of the mouse Y chromosome. Contrary to popular theory that Y chromosomes should be degenerate and gene poor, we find that the mouse male-specific region of the Y chromosome (MSY) is almost entirely euchromatic and contains about 700 protein-coding genes. Almost all of these genes belong to three acquired, massively amplified gene families that have no homologs on primate MSYs but do have acquired, amplified homologs on the mouse X chromosome. We propose that lineage-specific convergent acquisition and amplification of X-Y gene families is a result of sex-linked meiotic drive. Chapter 3 describes the gene regulatory program of meiotic prophase. Meiotic prophase comprises a complex chromosomal program results in the production of haploid gametes. This must be supported by a program of gene expression via which the required genes are induced. We interrogated gene expression in fetal ovaries over time and space, and in mutants of Dazl and Stra8 - key genes required for meiotic initiation. We determined that genes are regulated in three classes. Class 1 genes are expressed independently of Stra8, class 2 genes are expressed partially independently of Stra8, and Class 3 genes are dependent on Stra8 to be expressed. All genes require Dazl to be expressed. We propose that the Stra8-independent genes may represent genes required to be expressed prior to or early during meiotic initiation. Following initiation of meiosis, we found that Stra8 is required to induce down-regulation of its own expression. We propose that induction of down-regulation of the initiating signal by itself serves to ensure timely cessation of and one-time activation of the chromosomal program of meiotic prophase.
by Ying Qi Shirleen Soh.
Ph. D.

Style APA, Harvard, Vancouver, ISO itp.

21

Daldello, Enrico Maria. "Arpp19 et Cdc6, deux régulateurs majeurs des divisions méiotiques de l'ovocyte de Xénope". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066116/document.

Pełny tekst źródła

Streszczenie:

L’objectif de cette thèse a été de comprendre deux caractéristiques majeures des divisions méiotiques chez la femelle: le blocage en prophase de 1ère division méiotique qui permet à l’ovocyte d’accumuler des réserves énergétiques et des déterminants nécessaires au développement embryonnaire ; et l’absence de phase-S entre les deux divisions méiotiques ce qui permet de former des cellules haploïdes aptes à la fécondation. Pour cela, j’ai choisi comme modèle d’étude l’ovocyte de Xénope qui permet de suivre ces processus in vitro en réponse à la progestérone. L’ovocyte subit les deux divisions méiotiques grâce à l’activation du facteur universel de la division cellulaire, le MPF, et se bloque en métaphase de 2ème division méiotique dans l’attente d’être fécondé. Chez tous les vertébrés, le 1er arrêt en prophase dépend de l’activité de la protéine kinase dépendante de l’AMPc, PKA, dont l’inactivation est nécessaire pour la reprise de la méiose. Le substrat de PKA dans l’ovocyte était resté inconnu. Nous avons découvert que la protéine Arpp19, jusqu’alors connue pour son rôle positif dans l’activation du MPF, est phosphorylée par PKA de cette phosphorylation bloque l’activation du MPF nécessaire pour la levée du blocage en prophase. ARPP19 possède donc un double rôle, le 1er exercé comme substrat de PKA et responsable de l’arrêt en prophase, le second dans l’activation du MPF suite à un changement dans sa phosphorylation. Dans un second temps, nous avons étudié la protéine Cdc6, un acteur majeur de la réplication de l’ADN. Absente en prophase, Cdc6 s’accumule entre les deux divisions méiotiques ce qui permet à l’ovocyte d’acquérir la compétence à répliquer l’ADN. Cette compétence ne s’exprime pas ce qui permet de réduire de moitié la ploïdie. Nous avons montré que Cdc6 est un inhibiteur puissant du MPF capable de bloquer les divisions méiotiques et d’induire la réplication de l’ADN. Pour éviter ces effets délétères l’accumulation de Cdc6 est strictement régulée lors des deux divisions méiotiques, ce qui est absolument requis pour assurer l’enchainement des deux divisions cellulaires sans phase-S intercalaire
The goal of my PhD project was to understand two main features of the female meiotic division: the arrest in prophase of the 1st meiotic division that allows the accumulation of nutrients and determinants necessary for the embryonic cell cycles; and the absence of S-phase between the two meiotic divisions in order to produce haploid gametes. For this purpose, I studied Xenopus oocytes, a powerful model system that allows the biochemical analysis of these two processes in vitro. In ovary, oocytes are arrested in prophase I and resume meiosis in response to progesterone. The oocytes then proceed through the 1st and the 2nd meiotic divisions and halt at metaphase II, awaiting for fertilization. These two consecutive divisions are controlled by two waves of Cdk1 activation, the universal factor responsible for the entry into mitosis. I analysed the mechanisms responsible for arresting the oocyte in prophase I. In all vertebrates, this arrest depends on a high activity of the cAMP-dependent protein kinase, PKA, whose downregulation is required for the release of the prophase block. The substrate of PKA had never been identified up to date. I discovered that the small protein Arpp19, already known for positively regulating entry into M-phase, is phosphorylated by PKA in prophase I and is dephosphorylated upon progesterone addition, an event required for Cdk1 activation. Hence, Arpp19 has a dual function, responsible of the prophase arrest as a PKA substrate, and then converted into an activator of Cdk1 by changes of its phosphorylation pattern. The second part of my thesis has been dedicated to understanding the role and the regulation of the Cdc6 protein during meiotic divisions. This protein is essential for DNA replication in somatic cells. It is accumulated between the two oocyte meiotic divisions and restores the competence to replicate DNA in oocyte. However, this competence is repressed before fertilization, allowing formation of haploid cells. I found that the accumulation of Cdc6 is tightly controlled during meiotic maturation by the Cyclin B accumulation and the Mos/MAPK pathway. I further demonstrated that Cdc6 is a strong inhibitor of Cdk1 in Xenopus oocytes and that the timely accumulation of Cdc6 is required to coordinate the two meiotic divisions with no intercaling S-phase

Style APA, Harvard, Vancouver, ISO itp.

22

Eibes, González Susana. "Functional study of the NIMA protein kinases Nek9, Nek6 and Nek7 at the onset of mitosis. Control of the kinesin Eg5 and prophase centrosome separation". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/399449.

Pełny tekst źródła

Streszczenie:

Mitosis is a tightly regulated process that aims to ensure the correct distribution of the chromosomes between the two newly generated cells. Many protein kinases have been defined as essential for this process: cyclin- dependent kinases, Aurora family and Polo family kinases are some of the most relevant players. The objective of this thesis is to characterize one of the less studied kinase pathways involved in this process, which is constituted by the NIMA-related kinases Nek9, Nek6 and Nek7. Nek9 is activated at the onset of mitosis by a double step mechanism mediated by CDK1 and Plk1. Once Nek9 is activated it can bind to Nek6 and Nek7 and phosphorylate them, promoting their activation. Finally, Nek6 and Nek7 are responsible for the phosphorylation of the kinesin Eg5, promoting Eg5 accumulation at centrosome, and consequently, centrosome separation. The kinesin eg5 motor protein is considered as one of the major players for centrosome separation and formation of the bipolar spindle. The tetramer configuration allows Eg5 to bind antiparallel microtubules and slide them apart, exerting a force that promotes centrosome separation and the maintenance of the bipolar spindle. Centrosome separation, however, is a highly intricate process that involves several pathways, including Eg5 activity. Dynein presents a directed activity towards the minus ends of microtubules, which has a redundant role to Eg5 in centrosome separation. Dynein accumulation at the cell cortex and the nuclear membrane, through its adaptor BicD2, is also involved in centrosome tethering at the nuclear envelope, a necessary step prior to separation. Furthermore, dynein can control the position of Eg5 at the spindle via TPX2, an event that could also happen before nuclear envelope breakdown (NEB). Here we describe the conditions required for Eg5 accumulation at the centrosmes after Ser1033 phosphorylation. During the development of this project we have explored the essential circumstances for correct Eg5 localization in cells. By using protein-protein interaction techniques and shRNA depletion of protein candidates we have determined that another motor protein, dynein, together with the adaptor BicD2 and the protein TPX2 are responsible for Eg5 accumulation around centrosomes. Additionally, we proposed TPX2 as a novel Nek9 substrate and we have investigated the role of this phosphorylation, which affects TPX2 localization during prophase, before NEB. We present with this thesis a model for Eg5 accumulation at microtubule minus ends and centrosome separation during prophase summarized in the following points: 1) Dynein complex transports Eg5 towards the centrosome. Dynein interacts with Eg5 independently of the Ser1033 phosphorylation. The adaptor BicD2, which interacts directly with Eg5 tail domain, mediates the interaction. Dynein motility towards microtubule minus ends and the presence of BicD2 on the complex are required for Eg5 localization at centrosomes. Thus, the dynein complex is required for Eg5 transport to the centrosomes during G2-M transition. 2) TPX2 inhibits Eg5 motility in response to Ser1033 phosphorylation. TPX2 is necessary for the correct localization of Eg5 at centrosomes during prophase. TPX2 mislocalization at centrosomes without altering its overall levels leads to failed Eg5 localization, therefore the presence of TPX2 at centrosomes during prophase is required for Eg5 localization. TPX2 interacts with Eg5 during mitosis and the interaction is abolished when the Ser1033 can’t be phosphorylated. Thus, TPX2 is able to respond to Eg5 Ser1033 phosphorylation, which we propose is promoting the interaction between these two proteins, and consequently inhibiting Eg5 motility at centrosomal levels. 3) TPX2 phosphorylation by Nek9 promotes its centrosomal localization. Nek9 phosphorylation of TPX2 is responsible for TPX2 localization at the spindle poles during prophase. Nek9 phosphorylates TPX2 at residues that are proximal to a NLS, making TPX2 localization more cytoplasmic and promoting its accumulation to the area where Nek9 is more active, the centrosome.
La mitosis es un proceso altamente regulado cuyo objetivo es asegurar la correcta distribución de los cromosomas entre las dos células nuevamente generadas. Diferentes proteínas quinasas han sido definidas como esenciales en este proceso pero el objetivo de esta tesis es caracterizar una de las rutas de señalización menos estudiada, la cual la componen las NIMA quinasas Nek9, Nek6 y Nek7. Nek9 es activada al inicio de mitosis por un doble mecanismo mediado por CDK1 y Plk1. Una vez activada, se puede unir a Nek6 y Nek7 y fosforilarlas, promoviendo su activación. Finalmente, Nek6 y Nek7 son responsables de la fosforilación de la quinesina Eg5, promoviendo la acumulación de Eg5 en los centrosomas, y en consecuencia, la separación de los mismos en profase. Aquí describimos las condiciones necesarias para la acumulación de Eg5 en los centrosomas después de la fosforilación en la Ser1033. Durante el desarrollo de este trabajo hemos explorado las circunstancias esenciales para una correcta localización de Eg5 en las células. Usando técnicas de interacción proteína-proteína y técnicas de silenciamiento proteico de candidatos con shRNA hemos determinado que otra proteína motora, dineína, junto con el adaptador BicD2 y la proteína TPX2, son responsables de la acumulación de Eg5 alrededor de los centrosomas. Además, hemos propuesto a TPX2 como un nuevo substrato regulado por Nek9 y hemos investigado el papel de esta fosforilación, la cual afecta la localización de TPX2 durante profase, antes de la rotura de la membrana nuclear. Con esta tesis presentamos un modelo para la acumulación de Eg5 y la separación de los centrosomas en profase que puede ser resumido en los siguientes puntos: - El complejo de dineína transporta Eg5 hacia el centrosoma independientemente de la fosforilación en la Ser1033. El adaptador BicD2 media esta interacción uniéndose directamente al dominio C terminal de Eg5. -TPX2 inhibe movilidad de Eg5 en respuesta a la fosforilación en la Ser1033. - La presencia de TPX2 en los centrosomas es necesaria para la localización de Eg5. La fosforilación de TPX2 por Nek9 promueve la localización de TPX2 en los centrosomas durante la profase.

Style APA, Harvard, Vancouver, ISO itp.

23

Daldello, Enrico Maria. "Arpp19 et Cdc6, deux régulateurs majeurs des divisions méiotiques de l'ovocyte de Xénope". Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066116.pdf.

Pełny tekst źródła

Streszczenie:

L’objectif de cette thèse a été de comprendre deux caractéristiques majeures des divisions méiotiques chez la femelle: le blocage en prophase de 1ère division méiotique qui permet à l’ovocyte d’accumuler des réserves énergétiques et des déterminants nécessaires au développement embryonnaire ; et l’absence de phase-S entre les deux divisions méiotiques ce qui permet de former des cellules haploïdes aptes à la fécondation. Pour cela, j’ai choisi comme modèle d’étude l’ovocyte de Xénope qui permet de suivre ces processus in vitro en réponse à la progestérone. L’ovocyte subit les deux divisions méiotiques grâce à l’activation du facteur universel de la division cellulaire, le MPF, et se bloque en métaphase de 2ème division méiotique dans l’attente d’être fécondé. Chez tous les vertébrés, le 1er arrêt en prophase dépend de l’activité de la protéine kinase dépendante de l’AMPc, PKA, dont l’inactivation est nécessaire pour la reprise de la méiose. Le substrat de PKA dans l’ovocyte était resté inconnu. Nous avons découvert que la protéine Arpp19, jusqu’alors connue pour son rôle positif dans l’activation du MPF, est phosphorylée par PKA de cette phosphorylation bloque l’activation du MPF nécessaire pour la levée du blocage en prophase. ARPP19 possède donc un double rôle, le 1er exercé comme substrat de PKA et responsable de l’arrêt en prophase, le second dans l’activation du MPF suite à un changement dans sa phosphorylation. Dans un second temps, nous avons étudié la protéine Cdc6, un acteur majeur de la réplication de l’ADN. Absente en prophase, Cdc6 s’accumule entre les deux divisions méiotiques ce qui permet à l’ovocyte d’acquérir la compétence à répliquer l’ADN. Cette compétence ne s’exprime pas ce qui permet de réduire de moitié la ploïdie. Nous avons montré que Cdc6 est un inhibiteur puissant du MPF capable de bloquer les divisions méiotiques et d’induire la réplication de l’ADN. Pour éviter ces effets délétères l’accumulation de Cdc6 est strictement régulée lors des deux divisions méiotiques, ce qui est absolument requis pour assurer l’enchainement des deux divisions cellulaires sans phase-S intercalaire
The goal of my PhD project was to understand two main features of the female meiotic division: the arrest in prophase of the 1st meiotic division that allows the accumulation of nutrients and determinants necessary for the embryonic cell cycles; and the absence of S-phase between the two meiotic divisions in order to produce haploid gametes. For this purpose, I studied Xenopus oocytes, a powerful model system that allows the biochemical analysis of these two processes in vitro. In ovary, oocytes are arrested in prophase I and resume meiosis in response to progesterone. The oocytes then proceed through the 1st and the 2nd meiotic divisions and halt at metaphase II, awaiting for fertilization. These two consecutive divisions are controlled by two waves of Cdk1 activation, the universal factor responsible for the entry into mitosis. I analysed the mechanisms responsible for arresting the oocyte in prophase I. In all vertebrates, this arrest depends on a high activity of the cAMP-dependent protein kinase, PKA, whose downregulation is required for the release of the prophase block. The substrate of PKA had never been identified up to date. I discovered that the small protein Arpp19, already known for positively regulating entry into M-phase, is phosphorylated by PKA in prophase I and is dephosphorylated upon progesterone addition, an event required for Cdk1 activation. Hence, Arpp19 has a dual function, responsible of the prophase arrest as a PKA substrate, and then converted into an activator of Cdk1 by changes of its phosphorylation pattern. The second part of my thesis has been dedicated to understanding the role and the regulation of the Cdc6 protein during meiotic divisions. This protein is essential for DNA replication in somatic cells. It is accumulated between the two oocyte meiotic divisions and restores the competence to replicate DNA in oocyte. However, this competence is repressed before fertilization, allowing formation of haploid cells. I found that the accumulation of Cdc6 is tightly controlled during meiotic maturation by the Cyclin B accumulation and the Mos/MAPK pathway. I further demonstrated that Cdc6 is a strong inhibitor of Cdk1 in Xenopus oocytes and that the timely accumulation of Cdc6 is required to coordinate the two meiotic divisions with no intercaling S-phase

Style APA, Harvard, Vancouver, ISO itp.

24

Yerle-Bouissou, Martine. "Contribution à la carte génique du porc par hybridation moléculaire in situ sur des chromosomes en métaphase et en fin de prophase : application à l'étude du gène halothane". Toulouse, INSA, 1990. http://www.theses.fr/1990ISAT0018.

Pełny tekst źródła

Streszczenie:

L'analyse du genome chez l'homme et la souris est maintenant tres avancee grace a l'etablissement de cartes geniques detaillees. La situation est tout a fait differente dans le cas des especes domestiques ou les cartes geniques sont encore sommaires ou inexistantes. L'objectif de ce travail est d'une part, de contribuer a l'etablissement d'une carte physique globale pour l'espece porcine et d'autre part, de realiser la carte fine du chromosome 6, qui porte un gene d'interet zootechnique: le gene de sensibilite a l'halothane (hal). Nous avons etabli le caryotype des chromosomes porcins en fin de prophase, multipliant par deux le nombre de bandes g obtenues par rapport au caryotype standard. Nous avons developpe la technique d'hybridation moleculaire in situ sur des chromosomes en metaphase et en fin de prophase. A l'aide de cette technique, nous avons localise des genes moyennement repetes: l'interferon et le complexe majeur d'histocompatibilite ainsi qu'un gene unique codant pour la nucleoside phosphorylase. Concernant l'etude du gene hal, cinq marqueurs ont ete localises et ordonnes sur le chromosome 6 (ssc6). Cette etude nous a permis de montrer que le chromosome 6 (region: centromereq2. 1 et q. 2. 2q2. 5) est en partie homologue aux chromosomes 1 (region pterp36. 13) et 19 (region q13. 1q13. 2) humain. Grace aux resultats obtenus, un atelier pilote charge de l'etablissement d'une carte genique complete du porc, va etre developpe

Style APA, Harvard, Vancouver, ISO itp.

25

Finsterbusch, Friederike. "Analysis of gene expression data from Massive Parallel Sequencing identifies so far uncharacterised regulators for meiosis with one candidate being fundamental for prophase I in male and female meiosis". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-202144.

Pełny tekst źródła

Streszczenie:

Meiosis is a specialized division of germ cells in sexually reproducing organisms, which is a fundamental process with key implications for evolution and biodiversity. In two consecutive rounds of cell division, meiosis I and meiosis II, a normal, diploid set of chromosome is halved. From diploid mother cells haploid gametes are generated to create genetic individual cells. This genetic uniqueness is obtained during prophase of meiosis I by essential meiotic processes in meiotic recombination, as double strand break (DSB) formation and repair, formation of crossovers (CO) and holiday junctions (HJs). Checkpoint mechanisms ensure a smooth progress of these events. Despite extensive research key mechanisms are still not understood. Based on an analysis of Massive Parallel Sequencing (MPS) data I could identify 2 genes, Mcmdc2 and Prr19, with high implication in meiotic recombination. In the absence of Mcmdc2 both sexes are infertile and meiocytes arrest at a stage equivalent to mid-‐pachytene in wt. Investigations of the synaptonemal complex (SC) formation revealed severe defects suggesting a role for MCMDC2 in homology search. Moreover, MCMDC2 does not seem to be essential for DSB repair, as DSB markers of early and mid recombination nodules, like DMC1 and RPA, are decreased in oocytes. Nevertheless, late recombination nodules, which are positive for MutL homolog 1 (MLH1), do not form in both sexes. The absence of the asynapsis surveillance checkpoint mechanism in Hormad2 deficient ovaries with Mcmdc2 mutant background allowed survival of oocytes. This points into the direction that Mcmdc2 knockout oocytes get eliminated after prophase I due to failed homologous synapsis. Interestingly, MCMDC2 contains a conserved helicase domain, like the MCM protein family members MCM8 and MCM9. I therefore hyphothesize that Mcmdc2 promotes homolgy search.

Style APA, Harvard, Vancouver, ISO itp.

26

Borgne, Annie. "Etude de la regulation de cdc2/cycline b a la transition prophase/metaphase de l'ovocyte d'etoile de mer. Caracterisation des effets de la roscovitine, un nouvel inhibiteur chimique de cdk". Paris 6, 1998. http://www.theses.fr/1998PA066422.

Pełny tekst źródła

Streszczenie:

La transition prophase/metaphase du cycle cellulaire est regulee par cdc2/cycline b (ou mpf, m-phase promoting factor). En prophase, la kinase se trouve sous la forme d'un complexe inactif, cdc2 etant phosphorylee sur thr-14 et tyr-15 (forme t p-y p) et la cycline b etant non phosphorylee. L'activation de la kinase se deroule en deux etapes concomitantes : 1) dephosphorylation de cdc2 par la phosphatase cdc25, qui active la kinase (forme t-y), 2) phosphorylation de la cycline b, qui permet la translocation du complexe dans le noyau ou se trouvent ses substrats. En utilisant l'ovocyte d'etoile de mer comme modele cellulaire, nous avons montre que la dephosphorylation de cdc2 in vivo et in vitro se deroule en deux etapes, la dephosphorylation de la thr-14 precedant celle de la tyr-15. La forme transitoire de cdc2 (t-y p) est partiellement active. Ces resultats laissent supposer que la forme t-y p peut etre impliquee dans l'amplification auto-catalytique du complexe. Nous avons egalement etudie la regulation de la phosphorylation de la cycline b. Nous avons mis au point une methode de detection de l'activite cycline b kinase in vitro. Nos resultats montrent que : 1) la phosphorylation de la cycline b n'est pas requise pour l'activite kinase du complexe, 2) cdc2 est responsable de la phosphorylation (shift) de la cycline b en metaphase, 3) la phosphorylation de la cycline b est une reaction intra-mpf. Enfin, nous avons caracterise les effets biochimiques et cellulaires de la roscovitine, un nouvel inhibiteur chimique de cdk. Ce derive de purine inhibe specifiquement cdc2, cdk2 et cdk5 et possede un pouvoir inhibiteur 10 fois superieur a l'olomoucine. La roscovitine empeche la replication de l'adn dans les extraits d'ufs de xenope et provoque l'arret du cycle en g 2/m dans les ovocytes, embryons et lignees de cellules de mammiferes testees. La cible physiologique en prophase de l'inhibiteur est probablement le complexe cdc2/cycline b.

Style APA, Harvard, Vancouver, ISO itp.

27

Liang, Lu. "Variation in Campylobacter phage and prophage". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41924/.

Pełny tekst źródła

Streszczenie:

Campylobacter is a bacterial pathogen commonly responsible for foodborne gastroenteritis worldwide. Due to the rapid development of resistance to antibiotics, many alternative interventions have been studied and bacteriophage therapy is one of them. To maximise the impact of the intervention and to ensure it remains sustainable it important to study the ecology and coevolution of Campylobacter and the bacteriophage that infect the pathogen. Coevolution interactions between Campylobacter and bacteriophage drive rapid molecular change and contribute to a higher mutation rates for both parties. In this study genetic modifications were examined in the bacterial host and phage arising either in vivo or in vitro. We observed the impact of C. jejuni containing Mu-like pro-phage on campylobacters populating the caeca of commercial broiler flocks. The Mu-containing campylobacters initially colonised and became the dominant strain, only to be out-competed before depopulation of the broiler house. The presence of the transposable Mu-like prophage ultimately proved to be a limitation in the fitness of the host. Campylobacter-specific phage CP30 is a T4-like phage of the Eucampyvirinae that was isolated from a farm with several other phage showing differences in host range of contemporary farm isolates. After serial passage the phage population acquired sequence variants. One newly characterised sequence type, CP30C, was defective in a tail fibre protein and revealed reduced adsorption ability and sensitivity against C. jejuni host strains. Whole genome sequencing identified host mutation in C. jejuni carrier state strains that maintain viability despite the continual production of virulent phage. A point mutation in the flhF gene (flhF(T368A)) was hypothesised to contribute to the non-motile phenotype of carrier state strains. Expression of flhF(T368A) in a flhF knockout background provedto have impaired motility, exhibit structural defects in flagella synthesis, were less susceptible to phage infection and show down regulation of σ28 dependent and σ54 dependent flagellar associated genes. Recombinant protein expression of FlhF demonstrated the protein to have GTPase activity and the FlhF(T368A) to have reduced enzyme activity, greater thermal sensitivity and to be impaired in protein folding compared to wild type FlhF.

Style APA, Harvard, Vancouver, ISO itp.

28

Finsterbusch, Friederike [Verfasser], Attila [Akademischer Betreuer] Toth, Anthony [Gutachter] Hyman i Attila [Gutachter] Toth. "Analysis of gene expression data from Massive Parallel Sequencing identifies so far uncharacterised regulators for meiosis with one candidate being fundamental for prophase I in male and female meiosis / Friederike Finsterbusch ; Gutachter: Anthony Hyman, Attila Toth ; Betreuer: Attila Toth". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1160874816/34.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

29

Louis, Séverine. "Localisation par immunohistochimie des cellules immunoréactives à la dopamine et à la noradrénaline dans les ganglions d'un mollusque bivalve Mya arenaria et effets de la sérotonine sur la dissolution de la vésicule germinale des ovocytes bloqués en prophase I de la méiose /". Thèse, [Rimouski, Québec] : Université du Québec à Rimouski, 2007.

Znajdź pełny tekst źródła

Streszczenie:

Thèse (M. Sc.) -- Université du Québec à Rimouski, 2007.
Titre de l'écran-titre (visionné le 10 avril 2008). Mémoire présenté à l'Université du Québec à Rimouski comme exigence partielle du programme de maîtrise ès Sciences en océanographie. CaQRU CaQRU Comprend des réf. bibliogr. Publié aussi en version papier. CaQRU

Style APA, Harvard, Vancouver, ISO itp.

30

Brumby, Anthony Mansfield. "The control of prophage induction in coliphage 186 /". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phb893.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

31

Leslie, Kevin Alexander. "Investigation of Prophage in Clinical Isolates of H pylori". W&M ScholarWorks, 2013. https://scholarworks.wm.edu/etd/1539626941.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

32

Boullis, Jean-Jacques. "Mably, prophète de l'esprit national". Aix-Marseille 1, 1990. http://www.theses.fr/1990AIX10051.

Pełny tekst źródła

Streszczenie:

Parmi toutes celles des reformateurs, l'oeuvre de mably se detache par l'audace meme de son "esprit critique" au sens d'entreprise destructrice denoncee par comte. Elle s'acharne a demanteler les assises de la monarchie hereditaire, en epaulant, notamment, les luttes des parlements contre le "despotisme ministeriel", en les incitant a se faire de "nouveaux droits". Ce nostalgique d'une egalite a jamais perdue invoque, certes, comme conditions du contrat originaire, les principes du droit naturel. Mais audela de cette armature theorique, leur portee subversive tient au fait qu'ils nous font connaitre nos droits imprescriptibles* le droit d'avoir ses opinions, de resister aux abus, de rester "libres dans la societe", en nous rappelant le bonheur ou nous destinait la nature. Sans eux, impossible de demeler, en tout acte historique, sa part d'injustice, ou de droiture. . . Le specialiste du "droit public de l'europe" va condronter, a la lumiere de ces principes, les merites des constitutions europeennes, leur capacite d'affermir la liberte de certains peuples, ou de s'en rapprocher. Un "droit des gens" doit representer a la raison des gouvernants la necessite de lui subordonner tout patriotisme. En puisant des lecons dans les bilans des proces de declin, des rares "revolutions heureuses". L'historien ne cesse de traquer les symptomes des "passiosn agreables", les ravages provosues par "l'avarice et l'ambition". Certes, le souhait de charger de futurs "etatsgeneraux" de l'integrale "puissance legislative" trahit bien un projet revolutionnaire (conforte, au surplus, de l'entretien du "mythe carlovingien"). Seulement il est tempere par la "these des contreforces", prete a confier la distribution des pouvoirs - dans la

Style APA, Harvard, Vancouver, ISO itp.

33

Owen, S. V. "Exploring the prophage biology of Salmonella enterica serovar Typhimurium ST313". Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3011773/.

Pełny tekst źródła

Streszczenie:

In the past 30 years, Salmonella bloodstream infections have become a significant health problem in sub-Saharan Africa and are responsible for the deaths of ~390,000 people each year. The disease is largely caused by a recently described sequence type of Salmonella Typhimurium: ST313. Comparative genomic analysis showed that the ST313 lineage is closely-related to the ancestral gastroenteritis-associated Typhimurium sequence type ST19, but carries a distinct prophage repertoire. I hypothesised that prophages contribute to the biology of this clinically-relevant ST. In this thesis I show that the African ST313 representative strain D23580 contains 5 full length prophages. Prophage BTP1 and BTP5 are undescribed, novel prophages specific to African ST313 strains, whilst Gifsy-2, ST64B and Gifsy-1 are well-characterised prophages found in other strains of S. Typhimurium. Of the five prophages, only BTP1 and BTP5 showed evidence for functional phage production, and mutations responsible for the inactivation of Gifsy-2, ST64B and Gifsy-1 were identified. The BTP1 prophage spontaneously induced at a prolific rate, estimated to result in the phage-mediated lysis of approximately 0.2% of the lysogenic cell population. A GFP reporter system was developed to visualise the spontaneous induction of the BTP1 prophage at the single-cell level. Though the BTP5 phage could not be studied using traditional plaque assay methodology, there was evidence that the BTP5 prophage was capable of forming viable BTP5 phage that could lysogenise naïve hosts. I analysed the genomes of recently discovered ST313 isolates from the UK and show that ST313 in the UK represents a distinct population of antibiotic susceptible strains associated with gastrointestinal infection. Additionally, analysis of the UK-ST313 genomes indicated that the BTP1 and BTP5 prophages were acquired independently by the two African ST313 lineages, showing convergent evolution to acquire and conserve the BTP1 and BTP5 prophages. Finally I present evidence that the prophages, in particular BTP5, effect the global gene expression of ST313, and the ST313-td gene of BTP1 mediates lysogenic conversion by functioning as a superinfection immunity factor against infection by Salmonella phage P22. The implications of these findings for understanding the pathogen in terms of ecological niche, host range and invasiveness in humans is discussed.

Style APA, Harvard, Vancouver, ISO itp.

34

Benoit, Jain Madhu. "Shelley, prophète de la non-violence". Paris 4, 1995. http://www.theses.fr/1995PA040160.

Pełny tekst źródła

Streszczenie:

Porté au firmament littéraire pour son œuvre poétique, Percy Bysshe Shelley est demeure dans l'ombre en tant que théoricien politique. Même Mohandas K. Gandhi, qui puisa sans doute pour une large part son inspiration dans les écrits du poète et auprès des disciples de celui-ci, ne lui a jamais rendu d'hommage public. Pourtant, Shelley est le père de la non-violence. Cette doctrine a, de l'indépendance de l'Inde à la fin de l'apartheid en Afrique du sud, marqué de son sceau plusieurs tournants de l'histoire récente. Notre travail a pour but d'étudier la théorie de la non-violence, telle qu'elle a été élaborée par Shelley dans un premier temps, et de retracer la filiation entre le poète et le mahatma dans un deuxième temps. Bien que cette recherche porte principalement sur Gandhi, il ne fut pas le seul citoyen illustré à être influencé par Shelley. Nous avons mentionné pour mémoire d'autres shelleyens qui ont laissé leur empreinte sur la politique contemporaine. Nous avons également tenté d'évaluer l'influence shelleyenne sur les stratégies de la non-violence utilisées dans des conflits sociaux au XXème siècle, afin de rendre au poète l'hommage qui lui est dû
Percy Bysshe Shelley has long been ranked amongst the greatest English poets but he has never been given full credit as a political thinker. Even Mohandas K. Gandhi, who is undoubtedly greatly indebted to the poet, both directly and indirectly, never acknowledged this debt. Nevertheless, Shelley is the source of Gandhi’s doctrine of non-violence. A doctrine which has left its mark on recent history, from the Indian struggle for independence right up to the nineties, including such brilliant examples as the abolition of apartheid in South Africa. The aim of the present study is firstly to study the theory of non-violence as conceived by Shelley, and secondly, to trace the link between the mahatma and the poet. Although the present work focuses on Gandhi, he is far from being the only personality to have followed shelleyan theories. Keeping this in mind, we have mentioned, albeit briefly, other eminent shelleyans who have influenced contemporary politics. We have also tried to assess Shelley’s impact on non-violent strategy, as it has been used during various social conflicts in the XXth century, in an attempt to give the poet credit long overdue, particularly in the annals of non-violence

Style APA, Harvard, Vancouver, ISO itp.

35

Davies, Emily. "The role of prophages in Pseudomonas aeruginosa". Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2034639/.

Pełny tekst źródła

Streszczenie:

Pseudomonas aeruginosa is a common opportunistic respiratory pathogen of individuals with cystic fibrosis (CF), capable of establishing chronic infections in which the bacterial population undergoes extensive phenotypic and genetic diversification. The Liverpool Epidemic Strain (LES) is a widespread hypervirulent and transmissible strain that is capable of superinfection and is linked to increased morbidity and mortality, relative to other P. aeruginosa strains. The LES has six prophages (LESφ1-6) within its genome, of which three are essential to the competitiveness of this strain. Temperate bacteriophages are incredibly common in bacterial pathogens and can contribute to bacterial fitness and virulence through the carriage of additional genes or modification of existing bacterial genes, lysis of competitors, or by conferring resistance to phage superinfection. Furthermore, the LES phages are detected at high levels in the CF lungs and have been implicated in controlling bacterial densities. The aims of this study were to (i) further characterise the LES phages and their induction, (ii) determine the extent to which the LES phages contribute to bacterial phenotypic and (iii) genetic diversification and (iv) determine how the LES phages affect host competitiveness, using a variety of in vitro and in vivo infection models. LES phages are continuously produced by spontaneous lysis and this study found that environmental factors that are common to the CF lung, such as oxidative stress, pharmaceutical chelating agents and antibiotics, can alter phage production by clinical LES isolates. Characterisation of the phages highlighted differences between the phages with regards to their lytic cycles and ability to propagate in different environments. P. aeruginosa undergoes extensive phenotypic diversification in an artificial sputum model (ASM) of infection, similar to that observed in chronic CF infections. Hypermutability, loss of motility and auxotrophy were phenotypes observed in bacteria evolved for approximately 240 bacterial generations in ASM in the presence and absence of the LES phages. However, the LES phages accelerated this process; loss of twitching motility occured earlier in populations evolved in the presence of phages. Sequencing of evolved populations revealed a high level of genetic diversification, with genes involved in motility, quorum sensing and genetic regulation experiencing loss of function mutations in parallel populations. In phage treated populations, LESφ4 had disruptively integrated into motility and quorum sensing genes, suggesting that temperate phages can provide an alternative (and quicker) route to adaptation. LES prophage carriage is important for bacterial competitiveness; PAO1 LES Phage Lysogens (PLPLs) successfully invaded a phage-susceptible population in vitro from when initially rare. Strain invasiveness was dependent on the LES prophage; LESφ4 lysogens were more invasive than PLPLφ2 or PLPLφ3, whereas carriage of all three prophages accelerated bacterial invasion. PLPLφtriple could also invade a susceptible competitor population in a rat model of chronic lung infection, although not as successfully as in vitro. These data suggest that prophage carriage is important for LES competitiveness and that phage-mediated lysis of phage-susceptible competitors may explain why LES is adept at superinfection. The study indicates that the LES phages are important drivers of bacterial diversification and evolution and confer a competitive advantage to their bacterial host. This may help explain why the LES is so successful, and the high prevalence of polylysogeny in bacterial pathogens.

Style APA, Harvard, Vancouver, ISO itp.

36

Décimo, Marc. "Saint Jean-Pierre Brisset grammairien et prophète". Paris 10, 1987. http://www.theses.fr/1987PA100122.

Pełny tekst źródła

Streszczenie:

C'est une étude de l'ensemble des œuvres de Jean-Pierre Brisset (1837-1919): art de nager, grammaires et livres prophétiques. La première partie détermine les options linguistiques de Brisset par rapport à la grammaire scolaire et les grands courants linguistiques du temps. L’analyse des méthodes et points grammaticaux étudiés par Brisset font apparaitre des structures répétitives, systématiques livrées à l'interprétation. Où il est question de lire des désirs et des pulsions dans des théories grammaticales. La deuxième partie s'intéresse aux œuvres "révélées", essentiellement celles de 1883 et 1889, ou Brisset découvre que le latin n'existe pas, que l'homme descend de la grenouille et les vertus du calembour. On y répertorie les procédés, les influences possibles et, à travers cette description, on essaie de relier les grands mythes brissettiens, de les interpréter, et de les mettre en rapport avec les déductions déjà menées par l'étude des grammaires, en somme de reconstituer l'unité de cette pathographie qui fait passer d'un art de nager (1870) par lequel on peut apprendre la brasse au mythe de la grenouille, ancêtre de l'homme ; unité décelée par les structures, leur description systématique qui renvoie de fait à la structure psychotique du sujet. On aboutit au ressassement de certaines formes, images essentiellement du morcellement et du regroupement illustration exemplaire d'un cas de délire paraphrénique (comme celui du président Schreber), étonnant par sa richesse et qui fait de Brisset, assurément, un écrivain, inévitablement à mettre en connexion avec Jarry ou Roussel
This is a study of the comprehensive works of Jean-Pierre Brisset (1837-1919): the art of swimming, grammar and prophetical books. In the first part, Brisset's linguistic options are specified in relation with school grammar and the main linguistic currents of the time. From analysis of methods and grammatical shapes which are studied by Brisset, repetitive, systematic structures appear, open to interpretation. It is a matter of reading yearnings and dashes in grammatical theories. The second part deals with "revealed" works, mainly those of 1883 and 1889, in which Brisset discovers the non-existence of the latin language, the frog as the originator of mankind and the quality of puns. This work lists procedures and possible influences. Through this description it tries to link the great brissettian myths, in order to give them interpretations and to relate them with deductions already arisen from grammatical studies. In fact to tie components of this pathography, through which one can switch from the craft of swimming (1870) -leading to practice of breast stroke - to the myth of the frog, the ancestor of mankind. Having disclosed unity through structures, their systematic description brings back to the psychotic structure of Jean-Pierre Brisset. Certain shapes are hacked back, pictures of scatterings and amalgamatings, exemplary illustrated of a case of paraphrenical delirium (as president schreber had) whose surprising richness undoubtably connects Brisset to Jarry or Roussel: Brisset is a writer

Style APA, Harvard, Vancouver, ISO itp.

37

Windhorst, Daniel [Verfasser]. "Analysis and characterization of the prophage content in Salmonella Enteritidis / Daniel Windhorst". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1009416308/34.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

38

Bouchard, Gilles. "André Naud, témoin de sa génération-- et prophète?" Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28203/28203.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

39

Kessler, John. "Le rôle du prophète dans le livre d'Aggée". Paris 4, 1995. http://www.theses.fr/1994PA040277.

Pełny tekst źródła

Streszczenie:

Cette thèse constitue une enquête sur le rôle prophétique au début de la restauration juive (539-515 av. Notre ère). Une analyse des conditions démographiques,économiques,religieuses et sociologiques établit les paramètres dans le cadre desquels l'office prophétique s'exerçait. Ces conditions excluent certaines hypothèses sur le rôle du prophète à cette époque,à savoir le prophète était un zélote ou un partisan de groupes sectaires. Le livre d'Aggée peut être utilisé à des fins de reconstitutions historiques. Le livre présente Aggée comme un prophète préexilique typique. Une analyse des mots d'Aggée révèle que le rôle prophétique était devenu foncièrement lié à la transmission des traditions religieuses. Aggée,à travers plusieurs démarches herméneutiques novatrices,adapte et remanie la tradition religieuse antérieure de façon qu'elle soit applicable aux conditions de l'époque postexilique. Par ce moyen,Aggée réussit à promouvoir la réédification du temple jérusalemite et à établir la continuité entre la communauté postexilique et l'Israe͏̈l d'antan
This thesis is an historical investigation of the prophetic role in the early Judaean restoration (539-515 BC),especially as evidenced in the book of Haggai. .

Style APA, Harvard, Vancouver, ISO itp.

40

Menouni, Rachid. "Maintien des prophages dans les génomes d' entérobactéries". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4008.

Pełny tekst źródła

Streszczenie:

Les bactériophages sont les virus spécifiques des bactéries. Ils sont considérés comme les entités biologiques les plus abondantes de la biosphère (1031 au total). Une grande partie des bactériophages sont dits tempérés de part leur propriété à intégrer leur génome dans celui de leur hôte et à s'y maintenir en état de réplication passive appelé lysogénie. Les gènes de prophages apportent de nouvelles propriétés à l'hôte via la conversion lysogénique. De nombreux prophages défectifs et fonctionnels sont maintenus dans les génomes bactériens. Nous avons émis l'hypothèse que des stratégies de maintien aient été sélectionnées pour maintenir cette source de gènes, même si elle est potentiellement dangereuse car les prophages peuvent être induits dans des conditions de stress.Nos résultats suggèrent que le maintien de la lysogénie d'une catégorie de prophages, qui présente une organisation génétique atypique du module de recombinaison spécifique de site, est sous le contrôle du facteur de terminaison de la transcription Rho. Pour ces prophages, qu'ils soient défectifs ou fonctionnels, leur induction par inactivation de Rho, fait intervenir une nouvelle voie d'induction lytique indépendante de la voie classique via la réponse SOS.Ces interactions hôtes-virus reflète la coévolution de ces microorganismes, qui permet l'acquisition de gènes via le transfert horizontal tout en contrôlant l'expression des gènes délétères. Ceci permet l'acquisition de nouvelles propriétés et l'adaptation de l'hôte à différentes conditions environnementales
Bacteriophages are the most abundant biological entities in the biosphere. A majority of them are temperate phages that are able to integrate their genome into the host and replicate passively in a lysogenic state. Hosts frequently benefit from such massive gene acquisition through lysogenic conversion. As prophages may be beneficial to their hosts, we hypothesize that hosts adapted strategies for maintaining that gene source. Since prophages integrate into and excise from the host chromosome through site-specific recombination (SSR), we investigated whether regulation of SSR at the level of gene expression could be involved in the maintenance process. Our results suggest that lysogeny maintenance of a class of prophages, which all share a same unusual genetic organization, are controlled by the transcription termination factor Rho. Rho is not only involved in horizontally acquired gene silencing but also in prophage maintenance, which can be seen as an adaptation of the host to maintain prophage genes. For these prophages, whether defective or functional, their induction by the inactivation of Rho, involves a new pathway of lysogeny escape, which is independent of the classical pathway via the SOS response. This newly characterized interaction reflects the coevolution of host and viruses, which allows the acquisition of genes, and thus new properties, via horizontal transfer, while controlling the expression of deleterious genes

Style APA, Harvard, Vancouver, ISO itp.

41

Berlogea, Ana. "Un prophète à Tophet : August Strindberg relit Jérémie". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0162.

Pełny tekst źródła

Streszczenie:

Un geste accompli au cours d’une représentation théâtrale et un geste prophétique peuvent-ils se rejoindre ? Un texte dramatique peut-il avoir lui-même vocation « prophétique », dans le sens où il éveille la conscience de ses destinataires, leur montrant le chemin de la vie et de la mort ? Telle est la question au centre de cette recherche. Pour l’aborder on propose d’étudier la manière dont l’auteur dramatique suédois August Strindberg (1849-1912), un des pères du théâtre moderne, reçoit et relit dans son dernier écrit pour le théâtre, La Grand-route (1909), la prophétie de Jérémie à Tophet (Jr 7, 31.32 ; 19, 6.11.12.13.14). Proclamant la parole divine essentiellement à Jérusalem à la fin du 6ème siècle av. J. C., Jérémie est aussi envoyé par Dieu à Tophet, pour poser un acte prophétique particulier – qui unit le geste à la parole pour renforcer cette dernière : Jérémie doit briser un vase pour annoncer la destruction de Jérusalem (19,11-12). Dans le dernier drame strindbergien, un prédicateur arrive dans une ville nommé Tophet, où il reçoit un vase japonais qui devient urne funéraire. Associé à un discours critique envers les perversions d’une société matérialiste, l’objet devient signe de la fin tragique d’un homme, associée au destin de sa ville, Hiroshima. À travers l’analyse comparative de la mission des sujets, des fonctions du lieu et du vase, objet empreint de la vie humaine, la thèse traite de la relation entre théâtre et prophétie, domaines abordés utilisant l’analyse performative et les principes de la grammaire narrative et structurale
Can a gesture made during a theatrical performance and a prophetic gesture be compared? Can a dramatic text itself have a "prophetic" vocation, in the sense that it awakens the consciousness of its audience? This is the central question of this research. To approach it, we propose to study the way in which the Swedish playwright August Strindberg (1849-1912), one of the fathers of modern theatre, interprets in his last drama, The Great Highway (1909), the prophecy of Jeremiah. Proclaiming the divine word essentially in Jerusalem, at the end of the 6th century BC, the prophet Jeremiah is also sent to Tophet (Jr 7: 31.32; 19, 6.11.12.13.14), a place that alone symbolizes the perversion of the Israelites (Jr 19:1-20:2). It is here that Jeremiah is invited to perform a prophetic act, which unites gesture with words to strengthen the latter: Jeremiah must break a vessel to announce the destruction of Jerusalem. In Strindberg’s drama, a preacher arrives in a town calls Tophet, where he receives a Japanese vase in order to turn it into a funeral urn. Associated to a critical speech against a materialistic society, the object becomes a sign of a merchant’s tragic life, linked to the destiny of his hometown, Hiroshima. Through a comparative analysis, that focuses on the mission of the hero, the functions of the place and of the vase – an object imprinted of man’s life and choices, the theses addresses the relationship between theatre and prophecy. The two domains are approached through a performative analyse, but also with the help of narrative and structural grammar

Style APA, Harvard, Vancouver, ISO itp.

42

Sockett, H. "Induction of mutations in the cI region of #lambda# prophage by thymine deficiency". Thesis, Queen's University Belfast, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374995.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

43

Panis, Gaël. "Caractérisation du module de recombinaison spécifique de site du prophage KplE1 d'Escherichia coli : de l'assemblage de l'intasome à la régulation des gènes". Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22089.

Pełny tekst źródła

Streszczenie:

KplE1 est l’un des dix prophages présents sur le chromosome de la souche Escherichia coli K12. Nous avons montré in vivo que ce prophage est compétant pour s’exciser du chromosome bactérien bien qu’il soit incapable de former des particules virales et de lyser son hôte. Au laboratoire, nous avons identifié les protéines IntS (intégrase) et TorI (RDF), codées sur le prophage KplE1, et la protéine IHF (NBP) de l’hôte comme seules impliquées dans le mécanisme de recombinaison spécifique de site (RSS). Nous avons cartographié sur les régions attL et attR, les sites de fixations des protéines de recombinaison permettant l’assemblage de l’intasome, le complexe nucléoprotéique compétant pour la RSS. L’ensemble de ces sites ainsi que les gènes intS et torI qui chevauchent respectivement les régions attL et attR, ont permis de définir un module de recombinaison de type KplE1. Ce module est très conservé et se retrouve chez des phages infectant différentes souches d’E. coli et de shigella. Le modèle en terme de RSS est celui décrit pour les bactériophages de type λ. Cependant, le nombre et l’organisation des sites de recombinaison suggèrent que l’architecture de l’intasome de type KplE1 diffère de celle de λ. Nos résultats renforcent ainsi l’idée que l’assemblage de l’intasome est spécifique du module de RSS considéré même si, in fine, la réaction catalysée demeure similaire.En ce qui concerne l’expression des gènes intS et torI, le fait que ces gènes soient localisés à chacune des extrémités du prophage, rend ainsi impossible leur couplage transcriptionnel à partir d’un promoteur commun au moment de la commutation lyse/lysogénie, tel qu’il est connu pour les phages lambdoïdes. De part son orientation atypique sur attL, la présence de sites de fixations des protéines IntS et TorI au niveau du promoteur du gène intS, nous ont logiquement amené à étudier sa régulation. Nous avons ainsi montré que le gène intS est négativement régulé par son propre produit ainsi que par la protéine RDF TorI. Nos résultats in vivo et in vitro indiquent que l’efficacité de la réaction de recombinaison excisive est intimement liée à la quantité d’intégrase présente, pouvant alors justifier la raison d’être de ce contrôle strict de l’expression du gène intS. En parallèle, une approche in silico a révélé que cette orientation atypique du gène codant pour l’intégrase est largement répandue sur les génomes des prophages, nous amenant à généraliser ce mécanisme atypique de régulation négative de l’intégrase
KplE1 is one of the 10 prophage region present on the Escherichia coli K12 chromosome. We showed in vivo that this prophage is fully competent to excise from the bacterial chromosome, although it is unable to form viral particles and lyse its host. In the laboratory, we have identified Ints (integrase) and TorI (RDF) proteins, encoded on the KplE1 prophage, and the host protein IHF (NBP) only involved in the mechanism of site-specific recombination (SSR). We have mapped on attL and attR regions, the binding sites of recombinant proteins for the assembly of the intasome, the nucleoprotein complex competent for SSR. All of these sites as well as intS and torI genes that overlap respectively attL and attR regions, have permit to define a KplE1 recombination module. This module is highly conserved and is found among phages infecting different E. coli and shigella strains. The model in terms of RSS is that described for λ bacteriophage. However, the number and organization of recombination sites suggests that the architecture of the KplE1 intasome differs from that of λ. Our findings reinforce the idea that the intasome assembly is specific to the SSR module considered even if ultimately the catalyzed reaction is similar.Regarding the intS and torI gene expressions, the fact that these genes are located at each end of the prophage, prevented the transcriptional coupling of these genes from a common promoter when the lysis/lysogeny switch occurs. Because of its atypical orientation on attL, and the presence of IntS and TorI protein binding sites that overlap its promoter region, we have logically studied the regulation of the intS gene. We have shown that intS is negatively regulated by both IntS and TorI proteins. Our in vivo and in vitro results suggest that the efficiency of the excision recombination reaction is closely related to the amount of this integrase, which can justify the strict control of the intS gene expression. In parallel, an in silico approach has revealed that the atypical orientation of the integrase gene is widespread in prophage genomes, leading us to generalize this atypical mechanism of negative regulation of integrase

Style APA, Harvard, Vancouver, ISO itp.

44

Titus, Andrew. "Sweet mother prophesy, a Buddha for an abominable age". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0005/MQ35535.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

45

Vincent, Cédric. "Frédéric Bruly Bouabré : un prophète africain dans l'art contemporain". Paris, EHESS, 2011. http://www.theses.fr/2011EHES0460.

Pełny tekst źródła

Streszczenie:

L'Ivoirien Frédéric Bruly Bouabré est sans aucun doute l'un des artistes contemporains les plus emblématiques apparus sur la scène internationale ces vingt dernières années. Il est aussi l'un des plus controversés en raison des circonstances imprévues qui l'ont amené à passer du statut de prophète raté à celui d'artiste accompli. Mais, trop souvent présenté hors de tout contexte proprement historique ou biographique, il est en conséquence perçu comme jloiment naïf. Ainsi son oeuvre se trouve valorisée, ou discréditée, moins pour sa complexité, voire ses contradictions internes, que pour une simplicité que la critique lui a peu ou prou inventée. Expliquer pourquoi et comment il est devenu un référent artistique est le principal sujet de cette étude, en faisant prévaloir des situations de coproduction et de traduction sur celles de l'artiste inventé ou de l'ariste par vocation, et ainsi établir une relation d'ordre dialectique entre prophète et artiste. Cette description nous conduit à circuler dans différents cadres: dans l'histoire du prophétisme ouest-africain, des savoirs africanistes et de l'histoire coloniale, des bouleversements récents de l'espace artistique. Bouabré est un point d'observation essentiel pour saisir les tensions et les résistances qui travaillent l'art contemporain et sa relation aux artistes issus de ses zones d'ombre. Notamment, il permet l'émergence d'une catégorie d'art contemporain africain, non pas comme une catégorie simplement chronologique ou temporelle, mais comme une catégorie esthétique, critique et normative
Frédéric Bruly Bouabré (Côte d'Ivoire) is one of the most emblematic figures to have emerged on the international arts scene over the past twenty years. He is also one of the scene's more controversial figures, due to a set of unpredictable circumstances that saw him move from the status of failed prophet to that of accomplished artist. Discussions of his work commonly lack a serious historical or biographical grounding, resulting in a picture of him as a sweetly naïve character. As a result, his oeuvre is hailed by some and discredited by others less for its inherent complexity or internat contradictions than on the grounds of a wholly invented simplicity. The study aims to explain why and how Bouabré has emerged as a point of reference. To do so, it privileges notions of co-production and translation over ideas of the artist as a self-taught individual driven by vocation alone. In the process, it posits a dialectical relationship between Bouabré's dual identities as prophet and artist. Close attention to how he has been shaped by interactions with others and to howthese interactions have played out over time draws attention to the dynamics of his prophetism. This, in turn, highlights a key aspect of his identity that has tended to be down. Bouabré constitutes a node, a key focus, to understand the spaces of tension and resistance that thicken the realm of contemporary art and complexify the relations it entertains with artists hailing from its shadowlands. Notably, it allows us to think through the emergence of contemporary African art not as a simply chronological or temporal category, but also, and more importantly,as an aesthetic, critical and normative category

Style APA, Harvard, Vancouver, ISO itp.

46

Durozoy, Anne-Sophie. "Le petit prophète Jonas au Moyen Âge : étude iconographique". Paris, EPHE, 2011. http://www.theses.fr/2011EPHE4016.

Pełny tekst źródła

Streszczenie:

Jonas est fréquemment représenté du XIIe au XVe siècle en France, dans les pays germaniques et en Angleterre. Il l’est moins en Espagne ou en Italie, ainsi que dans les pays scandinaves. La présente étude analyse textes et images pour évaluer la place du petit prophète au Moyen Âge, tant dans la pastorale, l’exégèse et les sommes théologiques que dans l’imaginaire. Jonas est un thème très important dans l’art paléochrétien. Les régions et les époques marquées par l’Antiquité ont accordé une place particulière à ce petit prophète, tout en modifiant le sens et l’iconographie des représentations. La baleine remplace la plante comme attribut principal. Les préoccupations quant au Salut de l’homme s’effacent derrière l’importance accordée à la Résurrection. Jonas est en effet une préfigure du Christ à double titre : avalé par la baleine, il annonce sa mort ; en sortant, il anticipe sa Résurrection. Il est également l’un des douze petits prophètes et est à ce titre régulièrement représenté, en général sans attribut, au milieu d’autres prophètes, pour insister sur la continuité du projet divin. Envoyé malgré lui à Ninive qui se repent de ses erreurs de manière spectaculaire, il devient paradoxalement une figure de la conversion, très appropriée quand, à la suite de Latran IV, la pastorale met l’accent sur la nécessité du sacrement de la pénitence. Jonas est le plus souvent accompagné du monstre marin, qui devient peu à peu baleine : la présence du petit prophète dans la gueule de l’animal permet de l’identifier. La fascination pour le merveilleux et l’espérance en la Résurrection de la Chair expliquent probablement l’importance accordée à l’épisode de la baleine
Jonah was often represented from the 12th to the 15th century in France, in the German countries as well as in England. He was less so in Spain, Italy, or in the Scandinavian countries. This study sets out to analyse texts and images so as to assess the part played by this character in pastoral, exegesis, theological compendiums, as well as in the the imaginary world. Jonah is a prominent figure in paleo-christian art. This little prophet was given a very unique treatment in the regions and periods that were influenced by Antiquity. Yet, they also reworked the meaning and the iconography of Jonah’s representations. The plant gave way to the whale as his main attribute. The emphasis before on the issue of Man’s Salvation shifted towards Resurrection. Indeed, Jonah prefigures the Christ in a double way. Being swallowed and cast out of the whale, he announces both Christ’s death and Christ’s resurrection. He is also one of the twelve minor prophets and in this respect he appears quite often - not always with an attribute - among other prophets, to show the continuity in God’s plan. He is ordered by God against his will to the city of Nineveh, which repents of his sins in a powerful way. Thus he appears quite paradoxically as a figure of repentance and that was used for pastoral purposes when the necessity of the sacrament of repentance arose after the Fourth Council of the Lateran. Jonah is often seen with a sea creature that would then be depicted in the form of a whale: his being in the belly of a great fish allows to identify him. The fascination for the marvellous as well as the hope of the Resurrection of the Flesh may account for the prominence of the whale episode

Style APA, Harvard, Vancouver, ISO itp.

47

Scott, Julie. "Prophage-regulated expression of DNA mismatch repair genes in group A streptococci genome strains". Oklahoma City : [s.n.], 2008.

Znajdź pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

48

Alem, Abdenbi. "Les magazi du Prophète dans le Coran et la poésie". Paris 4, 1986. http://www.theses.fr/1986PA040057.

Pełny tekst źródła

Streszczenie:

Cette thèse a étudié les expéditions du prophète Muhammad dans le coran et la poésie contemporaine au prophète. Cette étude porte sur le côté historique et littéraire. Cependant, l'étude littéraire prévaut. Quatre batailles et conquêtes ont été étudiées; badr, uhud, banu-n-nadir et al-handaq et banu qurayza. Chaque bataille et conquête a été étudiée historiquement, dans le coran et dans la poésie. Un chapitre pour l'étude historique de chaque bataille. Un autre pour l'expose de la bataille dans le coran. Un troisième pour l'étude des thèmes coraniques. Et un quatrième pour l'étude des thèmes poétiques. Quatre magazine donc quatre parties; pour chaque partie quatre chapitres. Une cinquième partie a été consacrée pour l'étude des figures de style dans les textes considères. La conclusion a traite trois points: l'influence religieuse sur la poésie. Les caractéristiques générales de cette poésie. Parallèle entre la manière du coran et de la poésie à traiter des magazi.

Style APA, Harvard, Vancouver, ISO itp.

49

Hadey, Jean. "Le statut du temple dans le livre du prophete jeremie". Université Marc Bloch (Strasbourg) (1971-2008), 1998. http://www.theses.fr/1998STR20034.

Pełny tekst źródła

Streszczenie:

Les differences textuelles entre la septante et le texte massoretique du livre de jeremie attestent que celui-ci est le produit d'une longue tradition litteraire. Il reste cependant legitime et possible de rechercher quelles ont ete les prises de position de jeremie dans les questions de son temps. Une telle recherche est ici entreprise a propos du temple. Dans une premiere partie est analysee la terminologie employee dans le livre de jeremie pour designer le temple, soit les termes hebreux equivalents a : maison, palais, sanctuaire, tente, patrimoine, trone, lieu. La seconde partie est consacree a l'etude des passages du livre de jeremie les plus pertinents pour la question du temple : les recits de jr. 27-28; 26; les discours en prose de jr. 3,14-18; 7,1-15; et les oracles prophetiques de jr. 11,15-17; 12,7-12; 4,19-26. Ces analyses permettent de conclure que le prophete jeremie a rejete l'ideologie judeenne du temple fondee sur la notion d'election de jerusalem comme lieu de la presence divine. Une partie des interventions redactionnelles a permis d'estomper cet aspect de la predication du prophete
It is obvious that the book of jeremiah is the result of a complex and lengthy process of literary evolution. It remains nonetheless possible to look for jeremiah's own declarations on several subjects. Such a quest is here undertoken concerning the question of the temple. The first part is a study of the terminology of the temple used in the book of jeremiah in the second part, several passages in jeremiah which appear to be concerned with the question of the temple are submitted to detailed exegesis. These analyses allow the conclusion that jeremiah rejected the judean temple ideology based on the election of jerusalem through god

Style APA, Harvard, Vancouver, ISO itp.

50

Bonneau, Guy. "Le prophète Marc, fonctions communautaires et stratégies rédactionnelles du second évangile". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1995. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21430.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

Rozprawy doktorskie na temat „Prophase I”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych