Reproduction de : Thèse de doctorat : Sciences de la vie et de la santé : Lille 1 : 2006. / N° d'ordre (Lille 1) : 3910. Articles en anglais reproduits dans le texte et en annexe. Résumés en français et en anglais. Titre provenant de la page de titre du document numérisé. Bibliogr. p. 242-290.

To investigate the relationship between maturation of the spheno-occipital synchondrosis (SOS) with cervical vertebrae (CVM), dental development of the canine (DI), chronologic age and intra-rater / inter-rater reliability using retrospective cone-beam computed tomography, seventy-seven subjects were randomly selected into six groups based on age and sex. Spearman correlation coefficients and tabulations between stages of maturation indices were evaluated. SOS maturation was significantly correlated with CVM and age (r > 0.8). A weaker significant correlation coefficient was found between SOS and DI (r > 0.6). All males with fused SOS were in CVM stage 4 or later, while all females were in at least CVM stage 3. No subjects with open SOS were in the post-pubertal growth spurt age group and no subjects with closed SOS were in the pre-pubertal growth spurt age group. SOS maturation showed substantial and significant inter-rater and intra-rater reliability (kappa > 0.7). / February 2015

La première ovulation induite par effet mâle chez la brebis anovulatoire en anoestrus saisonnier est souvent accompagnée d’un développement de cycles courts qui peuvent être contrecarrés par un traitement progestatif préalable. Nos travaux ont montré que la réponse au mâle est plus rapide en fin d’anoestrus en raison d’une sélection à J0 de follicules dont le stade de développement est plus avancé. En parallèle, ils apportent de nouvelles connaissances sur le mécanisme d’action par lequel la progestérone parvient à supprimer les cycles courts induits par effet mâle, en modulant certaines caractéristiques de la dynamique de croissance folliculaire et en améliorant l’activité stéroïdogénique des follicules préovulatoires. Cependant, d’autres études sont nécessaires pour étudier l’impact de ces effets sur la qualité ovocytaire et la fertilité de ces premières ovulations induites par effet mâle sur un plus grand nombre d’animaux. / The first ovulation induced by male effect in anestrous ewes during the non-breeding season usually result in the development of short cycles that can be avoided by progesterone priming. Our results show that ewes ovulate earlier in June due to selection at J0 of follicles in a more advanced stage of development. However, these observations seem to be unrelated to the luteal outcome after male effect. In parallel, we demonstrate the positive effect of progesterone on the completion of follicular growth and the improvement of the ability of these follicles to respond properly to LH surge and to synthesis ovarian steroids. However, further studies are required to understand whether these changes have functional consequences on the quality of oocytes induced by the male effect and in fertility after male effect on a large number of animals.

Made available in DSpace on 2016-12-08T16:44:45Z (GMT). No. of bitstreams: 1 PGPV13MA126.pdf: 1438995 bytes, checksum: 92c38a9e65801fc815fae80c57176981 (MD5) Previous issue date: 2013-08-27 / The Mixed Rain Forest, popularly known as Araucaria Forest, is being deforested. From its original surface only approximately 1% remains. This study aimed to contribute to the restoration /recovery process of this vegetation type through studies on seeds of three native species of trees and bushes, based on harvest, overcome of possible dormancy and seed processing. The species explored in this study were: Miconia cinerascens Miq. var. Cinerascens, Vernonanthura discolor (Spreng.) H. Rob and Sapium glandulosum (L.) Morong. The ideal time to harvest for all these species was defined, considering morphological maturation parameters. Fruit harvest was performed in two remnants of Araucaria Forest (Rio Rufino and Lages, both in Santa Catarina) in 2012 and 2013, where the matrices were selected. After harvest, the seeds were extracted manually and dry matter, moisture level, germination and seed vigor were evaluated. Germination tests were conducted in germinators of B.O.D type, where conditions were controlled according to each species involved. Gerbox was used and blotting paper worked as substrate for M. cinerascens var. cinerascens and V. discolor and sand used for S. glandulosum - all moistened whenever necessary. In seeds of M. cinerascens var. cinerascens were tested lighting conditions (constant light, alternation with 12 hours photoperiod and dark) and methods for overcoming seed dormancy (sulphuric acid for five minutes, gibberellic acid (GA3) at 0.2% for 12 hours, combination of sulphuric acid for five minutes and GA3 at 0.2% for 12 hours) were tested. To evaluate the germination of V. discolor, the experiment followed a factorial 2 x 2 format, consisting of two stages of maturation and two methods of processing the seeds (with and without blower). In the seeds of S. glandulosum, the experiment was in factorial 2 X 2 X 4, with two stages of maturation; seeds with and without pressure; and four methods of scarification: alternating temperature of 15/30 oC and GA3 at 0.2% for 24 hours; alternating temperature of 20/30 oC and GA3 at 0.2% for 24 hours, plus control. The evaluations were conducted every two days, when the seed that sprouted the first pair of cotyledons was considered germinated. The experiments were conducted from randomized design, with four replicates of 25 seeds per treatment. Data was evaluated at a significance level α = 0.05. It can be concluded that the fruit of M. cinerascens var. cinerascens should be picked in their ripe stage and their seeds germinated under constant light after being soaked in GA3 at 0.2% for 24 hours. The ideal time to harvest the fruit of the V. discolor is when their achenes are immature with green coloration; however, the use of the blower is not efficient for processing. As for S. glandulosum, the ideal time to harvest is when the fruit is open, with the aril of seeds red, and they should be germinated after pressure and use of GA3 for 24 hours at alternating temperatures of 15/30 ºC under constant light / A Floresta Ombrófila Mista, popularmente conhecida como Floresta das Araucárias, está em processo de desmatamento, restando da sua superfície original aproximadamente 1%. Este estudo visou contribuir no processo de restauração/recuperação desta fitofisionomia, ofertando tecnologia na germinação de sementes de três espécies arbóreo-arbustivas nativas, tendo como princípio a colheita na época ideal, a superação da possível dormência e o beneficiamento das sementes. As espécies alvo deste trabalho foram a Miconia cinerascens Miq. var. cinerascens, a Vernonanthura discolor (Spreng.) H. Rob e o Sapium glandulosum (L.) Morong. Para essas espécies citadas foram definidos estádios de maturação para proceder à colheita de frutos na melhor época possível, tendo como referência parâmetros de maturação. As colheitas dos frutos foram realizadas em dois remanescentes de Floresta Ombrófila Mista (Rio Rufino, SC e Lages, SC), em 2012 e 2013. Após a colheita dos frutos, as sementes foram extraídas de forma manual para todas as espécies. Foram avaliados a massa seca, o teor de água, a germinação e o vigor das sementes recém-colhidas. Os testes de germinação foram conduzidos em germinadores tipo B.O.D, em condições controladas de acordo com a espécie. Utilizou-se gerbox e como substrato papel mata-borão para a M. cinerascens var. cinerascens e para a V. discolor e areia para o S. glandulosum, umedecidos quando necessário. Em sementes de M. cinerascens var. cinerascens, foram testadas condições de luminosidade (luz constante, alternância com fotoperíodo de 12 horas e escuro) e métodos para superação da dormência das sementes (ácido sulfúrico por cinco minutos, ácido giberélico (GA3) a 0,2% por 12 horas, combinação de ácido sulfúrico por cinco minutos e GA3 a 0,2% por 12 horas). Para avaliar a germinação das sementes de V. discolor o experimento seguiu em esquema fatorial 2 X 2, constituído de dois estádios de maturação e dois métodos de beneficiamento das sementes (com soprador e sem de soprador). Nas sementes de S. glandulosum, o experimento definitivo seguiu em esquema fatorial de 2 X 2 X 4 (dois estádios de maturação; sementes com e sem pressão; e quatro métodos de superação de dormência: temperatura alternada de 15/30 oC e GA3 a 0,2% por 24 horas; temperatura alternada de 20/30 oC e ácido giberélico GA3 a 0,2% por 24 horas, além da testemunha em ambas as temperaturas alternadas. As avaliações foram realizadas a cada dois dias, onde se considerou germinada a semente que emitiu o primeiro par de cotilédones. Os experimentos foram instalados a partir do delineamento inteiramente casualizado, com quatro repetições de 25 sementes por tratamento. Os dados foram avaliados a um nível de significância α = 0,05. Foi concluído que os frutos de M. cinerascens var. cinerascens devem ser colhidos no seu estádio maduro e as suas sementes colocadas para germinar sob luz constante após imersão em GA3 a 0,2% por 24 horas. A época ideal para realizar as colheitas dos frutos de V. discolor é quando seus aquênios estiverem imaturos com coloração verde, no entanto o uso do soprador não foi eficiente. Já para o S. glandulosum, o momento ideal de colheita é quando o fruto estiver aberto, com o arilo das sementes vermelho, e colocadas para germinar após pressão e com uso de GA3 por 24 horas a uma temperatura alternada de 15/30 ºC sob luz constante

Submitted by Giovana Barros Nunes (giovanabnunes@hotmail.com) on 2018-04-12T15:28:06Z No. of bitstreams: 1 GBN VERSÃO FINAL DISSERTAÇÃO P IMPRESSÃO.pdf: 1111649 bytes, checksum: f77c4c688d28fc8ca13182c8832085f8 (MD5) / Rejected by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: No arquivo submetido ao repositório deve estar inserido o certificado de aprovação (documento obrigatório). A informação sobre a lombada não precisa conter no arquivo pdf inserido. Favor inserir o certificado de aprovação e submeter novamente a sua dissertação no repositório. Agradecemos a compreensão on 2018-04-13T11:25:20Z (GMT) / Submitted by Giovana Barros Nunes (giovanabnunes@hotmail.com) on 2018-04-13T14:08:12Z No. of bitstreams: 1 Dissertação GIOVANA BARROS NUNES VERSÃO DEFINITIVA Repositório.pdf: 1276204 bytes, checksum: 3aba64a51e863966cadeab46cfa01561 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-13T17:17:41Z (GMT) No. of bitstreams: 1 nunes_gb_me_jabo.pdf: 1276204 bytes, checksum: 3aba64a51e863966cadeab46cfa01561 (MD5) / Made available in DSpace on 2018-04-13T17:17:41Z (GMT). No. of bitstreams: 1 nunes_gb_me_jabo.pdf: 1276204 bytes, checksum: 3aba64a51e863966cadeab46cfa01561 (MD5) Previous issue date: 2018-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo foi desenvolvido com o objetivo de avaliar o efeito do precursor do peptídeo natriurético tipo C (NPPC) durante o cultivo de pré-maturação in vitro (pré-MIV) de oócitos bovinos sobre: 1) a progressão da maturação nuclear; 2) a expressão gênica das células do cumulus e 3) a aquisição da competência do oócito para o desenvolvimento embrionário in vitro. Os complexos cumulus-oócito (CCOs) foram pré-MIV com 100 nM NPPC por 8 horas (grupo NPPC) e, ao final do período, foram lavados para completa remoção do NPPC e submetidos à MIV por 22h. Após 8h de pré-MIV e após 8h de pré-MIV seguidas de 22h de MIV (duração total do cultivo = 30h) foram avaliadas a progressão da maturação nuclear e a expressão relativa de mRNA nas células do cumulus. O grupo controle (C) foi maturado na ausência de NPPC por até 30h, e as mesmas avaliações anteriores foram realizadas imediatamente após a remoção do ambiente folicular (C0), após 8h de cultivo (C8), após 22h de cultivo (C22) e após 30h de cultivo (C30). Em outro experimento, cujos tratamentos foram idênticos aos supramencionados, os oócitos foram fecundados ao término da MIV e foi avaliado o desenvolvimento embrionário até a fase de blastocistos. Após 8h de cultivo de pré-MIV, a análise da progressão da meiose demonstrou que o grupo C0 apresentou 58,9% de estruturas com configuração de GV1, enquanto que o grupo C8 apresentou apenas 13,9% de estruturas nesta configuração (P<0,05). A proporção de GV1 no grupo NPPC foi semelhante a ambos estes grupos (22,8%; P>0,05). Por outro lado, o grupo C8 apresentou maior taxa de GV3 em relação ao C0 (53,1% vs. 3,62%; P<0,05), sem diferenças com o grupo NPPC (38,7%; P>0,05). Ao final do cultivo de MIV, não foi observada diferença entre os grupos (C22 vs. NPPC vs. C30) com relação à maturação nuclear, todavia, houve maior taxa de oócitos degenerados no C30 em comparação com C22 (11,4% vs. 2,8%; P<0,05). A análise da expressão relativa de genes das células do cumulus após 8h de pré-MIV com NPPC evidenciou aumento (P<0,05) na expressão de genes relacionados à expansão destas células (GREM1, PTGS2/COX2, PTX3, TNFAIP6 e VCAN), à maturação oocitária (BDNF, EGFR, NOS3, PDE5A, PRKCD e STAT3) e ao desenvolvimento embrionário (IGF1R, KRT8 e LUM). Ao final do cultivo de MIV, observou-se no grupo NPPC que o gene PTX3, relacionado à expansão das células do cumulus, além dos genes AREG e BDNF, relacionados à maturação oocitária, e o gene LUM, relacionado ao desenvolvimento embrionário estavam mais expressos em comparação com o grupo C30 (P<0,05). Com relação ao desenvolvimento embrionário, os grupos experimentais não apresentaram diferença (P>0,05) quanto à taxa de clivagem (média de 73,22%). Embora o grupo NPPC não tenha diferido (P>0,05) de C22 e C30 quanto à taxa de blastocistos, houve diferença entre C22 e C30 (69,3 vs. 37,4; P<0,05). Todavia, não houve diferença entre os grupos com relação ao número de células totais (blastômeros) e apoptóticas (P>0,05). Em conclusão, o cultivo de pré-MIV de oócitos bovinos por 8h com 100nM NPPC não bloqueou a retomada da meiose, mas a progressão da meiose ocorreu de forma mais lenta e impediu o envelhecimento e degeneração dos oócitos. O cultivo de oócitos por tempo prolongado (30h) na ausência de NPPC foi prejudicial para o desenvolvimento embrionário, mas o tratamento com NPPC (8h pré-MIV+22h MIV = duração total de 30h) reverteu parcialmente este índice. / The aim of this study was to evaluate the effect of the C-type natriuretic peptide precursor (NPPC) during pre in vitro maturation culture (pre-IVM) of bovine oocytes on: 1) nuclear maturation progress; 2) gene expression in cumulus cells and 3) acquisition of competence for in vitro embryo development. Cumulus oocyte complexes (COCs) were pre-IVM with 100 nM NPPC for 8 hours (NPPC group) and then were washed for the complete removal of NPPC and submitted to IVM for 22h. After 8h pre-IVM followed by 22h IVM (total culture time = 30h) oocytes were evaluated for nuclear maturation progress and cumulus cells for relative mRNA expression. Control group (C) was IVM in the absence of NPPC for up to 30h and the same evaluations were made immediately after follicle removal (C0) and after 8h (C8), 22h (C22) and after 30h of culture (C30). In another experiment with the same treatment, the oocytes were fertilized at the end of IVM and embryo development to the blastocyst stage was evaluated. After 8 hours of pre-IVM culture, meiosis progression analysis showed 58.9% of oocytes in GV1 configuration in C0, while C8 had only 13.9% (P<0.05). The GV1 rates in NPPC did not differ from any group (22.8%; P>0.05). On the other hand, C8 showed higher rates of GV3 in comparison with C0 (53.1% vs. 3.62%; p<0.05) and no differences compared to NPPC (38.7%; P<0.05). At the end of IVM culture, no differences between groups (C22 vs. NPPC vs. C30) were observed in nuclear maturation, however, higher rates of degenerated oocytes were observed in C30 in comparison with C22 (11.4% vs. 2.8%; P<0.05). The relative gene expression analysis in cumulus cells after 8h pre-IVM with NPPC showed an up-regulation in genes related to cumulus cells expansion (GREM1, PTGS2/COX2, PTX3, TNFAIP6 and VCAN), oocyte maturation (BDNF, EGFR, NOS3, PDE5A, PRKCD e STAT3) and embryo development (IGF1R, KRT8 and LUM). At the end of IVM culture, the cumulus cells expansion related gene, PTX3, the oocyte maturation genes, AREG and BDNF, and the embryo development gene, LUM, were up-regulated in NPPC in comparison with C30 (p<0.05). Regarding embryo development, the cleavage rates did not differ in experimental groups (mean around 73,22%). Besides, blastocyst rates did not differ between NPPC (P>0.05) and the other groups, but there was a difference between C22 and C30 (69.3 vs. 37.4%; P<0.05). There was no difference between the groups in total cell number (blastomeres) and apoptotic cells (P<0.05). In conclusion, the pre-IVM culture of bovine oocytes for 8h with 100nM NPPC did not block meiosis resumption, but meiosis progression occurred more slowly and prevented aging and degeneration of the oocytes. The prolonged time of oocyte culture (30h) in the absence of NPPC was detrimental to embryo development, but NPPC treatment (8h pre-IVM + 22h IVM = total duration of 30h) partially reversed this effect.

La phase de maturation des graines est caractérisée par l’ac-quisition successive de composantes qui constituent la qua-lité physiologique d’un lot de semences, à savoir la toléranceà la dessiccation (capacité à survivre au retrait total de l’eaucellulaire), la longévité (capacité de survivre à l'état sec pen-dant le stockage), la dormance ainsi que la vigueur germina-tive (capacité à germer de façon rapide et homogène quelquessoient les conditions de l’environnement). La production desemences à haute qualité germinative représente un enjeumajeur pour les semenciers car elle constitue un levier clefpour augmenter les rendements agricoles. Cependant, lesmécanismes régulant l’acquisition de la qualité germinativeet en particulier la longévité restent peu connus. Une étudepréalable d’un réseau de co-expression génique de facteursde transcription avait identifi é trois gènes candidats associésà la longévité chez Medicago truncatula :MtABL (ABA INSEN-SITIVE4-LIKE), MtABI5 (ABA INSENSITIVE5) et MtHSFA2.2(HEAT SHOCK FACTOR A2.2). L'objectif de cette thèse était devalider ces gènes et d’en comprendre leur fonction chez Medicagotruncatula et le pois par la caractérisation de mutantsd’insertion et EMS. ABL et ABI5 jouent un rôle dans la matu-ration en régulant positivement la longévité alors que celle-ci n’est pas affectée dans les mutants hsfa2.2. Des étudestranscriptomiques et biochimiques montrent que ABL et ABI5régulent de manière complexe la photosynthèse, la dégrada-tion de la chlorophylle et l’accumulation des oligosaccharide / Seed maturation is characterized by the acquisition ofthe various components that collectively constitute thephysiological quality or vigor of the seed: desiccation tolerance(DT, i.e. the capacity to survive complete drying), seedstorability or longevity (the capacity to remain alive duringstorage), dormancy, as well as fast and uniform germinationand seedling emergence under stressful conditions. Thesetraits are pivotal to ensure rapid and homogenous seedlingestablishment required for stable yield and are a majoreconomic challenge for the seed industry. Despite theiragronomic importance, the mechanisms regulating theiracquisition, including longevity, are still poorly understood. InMedicago truncatula, a gene co-expression network inferredthat transcription factors such asMtABL (ABA INSENSITIVE4-LIKE), MtABI5 (ABA INSENSITIVE5) and MtHSFA2.2 (HEATSHOCK FACTOR A2.2) are putative regulators of seedlongevity. The aim of this thesis was to characterize theirroles in Medicago truncatula and Pisum sativum using Tnt1insertion and EMS mutants. ABL and ABI5 are positiveregulators of longevity while defects in hsfa2.2 do not affectit. Transcriptomic and biochemical analyses show that ABLand ABI5 are involved in the regulation of photosynthesisassociated genes, chlorophyll loss and accumulation ofraffi nose family oligosaccharides (RFO). ABI5 is also involvedin the accumulation of stress proteins such as LEA proteins.By establishing a link between degreening, RFO contents andlongevity, our work offers new opportunities to tackle a

Dans une démarche d’éco-innovation, les entreprises cherchent à inventer et mettre en oeuvre de nouvelles activités plus durables parfois en rupture avec leurs pratiques existantes, et qui entraînent des changements plus ou moins importants au sein de leurs offres, de leur business model, et parfois sur l’ensemble de leurs écosystèmes. Confrontée à de tels enjeux et des dynamiques associées souvent complexes de par leur nature parfois techniques, économiques, sociales, juridiques, politiques…, l’entreprise et les parties prenantes du projet en émergence semblent ne pas toujours réussir à suffisamment s’écarter consciemment des cadres cognitifs existants pour explorer des alternatives en adéquation avec les ambitions initiales d’un projet d’éco-innovation. Ainsi, les trajectoires empruntées par ces projets sont susceptibles d’entrainer par exemple une dilution des valeurs environnementales et sociales ou de provoquer l’abandon de projets par un manque de considération des dimensions techniques ou économiques.Les travaux présentés ici portent sur la phase de maturation des concepts éco-innovants et cherchent à développer des modalités d’accompagnement pour éviter ou surpasser de telles situations dites de « fixation collective ».L’approche méthodologique repose sur une recherche-action effectuée au sein de l’organisme d’accompagnement Apesa structurée en deux étapes :- L’analyse de trois cas de projets d’éco-innovation nous a d’abord permis de caractériser la problématique des pratiques d’accompagnement et plus précisément les fixations collectives présentes lors de la maturation des concepts.- Cette première étude a alimenté la démarche de conception mise en oeuvre pour élaborer la méthode MIRAS, l’apport principal de notre recherche.La méthode MIRAS propose un panel d’outils d’animation destinés aux acteurs de l’accompagnement pour aider les groupes projets lors des phases de maturation de leur concept et de leur potentiel de soutenabilité en visant un certain équilibre du triptyque économique – environnemental – social). Dans cette optique, MIRAS vise à adopter une pensée systémique, qui ne soit pas centrée seulement sur l’entreprise mais qui reconsidère l’ensemble des dimensions du « réseau élargi des parties prenantes ». / During the development of eco-innovations, companies are looking to implement a new activity that can create ruptures with its existing practices and cause many changes in their business model. In such complex situations, the stakeholders of emerging projects have some difficulties to consciously deviate from existing cognitive frameworks to explore alternatives in line with the initial goals of the project. Thus, they take trajectories that may lead to a dilution of the environmental and social values or cause the abandonment of projects. The work presented here focuses on the maturation of eco-innovative concepts and seeks to develop tools and methods to avoid and overcome such situations called collective fixations.The methodological approach is based on an action research conducted in the organization Apesa and structured in two steps:- The analysis of three case-studies of eco-innovative projects allowed us to characterize supporting practices and deepen our knowledge on the collective fixation present during the maturation of concepts.- This first study has fueled the design process of the MIRAS method, the main contribution of our research.The MIRAS method offers a toolkit designed for eco-innovation intermediaries in order to help them to structure their intervention during the stage of concept maturation. Specifically the tools help to improve the sustainability potential of concepts, to analyze project group behaviors during sessions and to revisit stakeholder networks so as to anticipate future mutations and news ways of incubation.

Doctorat en sciences psychologiques / info:eu-repo/semantics/nonPublished

La maturation des ARNt en 5' est réalisée par RNase P. C'est un ribozyme chez les bactéries, les fungi et les nuclei des mammifères et un enzyme protéique dans les plantes ou des organelles des mammifères qui s’appelle PRORP. Il y a trois PRORP dans A. thaliana. PRORP contiennent deux domaines : un domaine PPR qui reconnaît spécifiquement des séquences d'ARN et un domaine nucléase qui assure la coupure endonucléolytique 5' des précurseurs d’ARNt. Pendant ma thèse j'ai pu montré par des méthodes biophysiques et structurales comme SRCD et SAXS que PRORP1 et 2 sont composées en majorité des hélices alpha Elles ont un rayon de giration de 33 Å et contiennent deux domaines distincts avec et une dimension maximale de 110 Å. Pour le complex entre un substrat d'ARNt et PRORP une constante de dissociation de 1 uM a pu être confirmé par la microcalorimétrie, la thermophorèse et l'ultracentrifugation analytique. Ces analyses nous ont permis de construire un modèle PRORP et un substrat d'ARNt. / RNase P cleaves 5’ leaders of precursor tRNAs. RNase P is a ribozyme in bacteria, fungi and animal nuclei and a protein in animal organelles, plants and many other organism. There are three PRORPs in A. thaliana. MALS, SRCD and SAXS provided first structural information: 1) PRORPs are monomers in solution. 2) PRORP 1-2 have a high alpha-helical content. 3) PRORPs are composed of two distinct domains with a radius of gyration of 33 A. These results together with homology modelling enabled us to build a first model of PRORPs in complex with tRNA. Using three different methods, isothermal titration calorimetry, microscale thermophoresis and analytical ultracentrifugation, a binding constant of about 1 µM could be determined for the system PRORP2mDD and L5T0 tRNA. This helped us conducting a SAXS experiment taking into account the low resolution affinity and designed to provide the direct structural data of a complex of proteinaceous RNase P with a substrate tRNA.

La qualité nutritionnelle de la mangue se construit du champ à la mise sur le marché. Outre le stade de maturité à la récolte, les facteurs environnementaux comme l'irrigation en pré-récolte, ou la température de stockage en post-récolte peuvent avoir une incidence sur la composition du fruit. Les caractéristiques physico-chimiques de la mangue sont également reliées à sa réponse aux espèces réactives d'oxygène (ERO) générées naturellement par la maturation, mais aussi par les contraintes externes (stress abiotiques), avec une incidence directe sur la durée de vie commerciale et la qualité du fruit. Ce travail de thèse a pour objectifs d'évaluer les effets relatifs du stade de récolte, du déficit hydrique ou de la conservation au froid (7 et 12 °C) sur la capacité de réponse de la mangue Cogshall aux ERO et sa capacité de synthèse en caroténoïdes et en polyphénols, composés impliqués dans la qualité nutritionnelle et participant avec l'ascorbate à la régulation du stress oxydatif. L'identification des caroténoïdes et composés phénoliques de la mangue Cogshall, a permis (i) d'approfondir les connaissances existantes sur le cultivar et (ii) de disposer d'un référentiel pour évaluer l'impact des paramètres abiotiques étudiés. La maturation induit un stress oxydatif majeur, mais il est montré que le potentiel de régulation du stress oxydatif lié aux conditions environnementales est partiellement lié au stade de maturité. À la récolte à un stade vert-mature, le déficit hydrique appliqué se traduit par une augmentation du stress oxydatif, avec des teneurs plus élevées en H2O2 et des teneurs en ascorbate plus importantes pour les fruits les plus précoces, une synthèse des teneurs en composés phénoliques marquée. En revanche après maturation, le stress associé à la crise respiratoire estompe les tendances observées quel que soit le stade de récolte. La voie de biosynthèse des caroténoïdes est modulée par le déficit hydrique avec une accumulation marquée d'acide abscissique. Le stockage à basse température pendant 14 jours favorise le stress oxydatif. Après maturation à 20 °C, le stade de récolte et de la température appliquée vont moduler le métabolisme des mangues. Les fruits précoces stockés à basses températures ont les teneurs en caroténoïdes les plus faibles et une capacité de réponse peu développée aux ERO alors que des fruits plus avancés ont un système de défense plus actif et une meilleure accumulation des caroténoïdes. Enfin, les corrélations entre les descripteurs de qualité classiques et la composition des fruits mettent évidence des relations assez robustes entre teneurs en sucres et extrait sec soluble et caroténoïdes majoritaires et angle de teinte, mais montrent aussi des décalages entre caroténoïdes totaux et angle de teinte, entre acidité titrable et acides organiques, quand les fruits sont conservés au froid. / The construction of mango nutritional quality begins in the field and ends on the shelf. In addition to the ripening stage at harvest, environmental factors such as irrigation and post-harvest storage temperature can influence fruit composition. The physico-chemical properties of mango are also related to its response to reactive oxygen species (ROS) that are naturally generated during ripening, as well as to external constraints (abiotic stress), which have a direct impact on shelf life and fruit quality. The aim of this thesis is to evaluate the effects of harvest stage, water deficit and cold storage (7 and 12 °C) on the response ability of Cogshall mango towards ROS and on its ability to synthesize carotenoids and phenolics compounds involved in nutritional quality and that contribute, with ascorbate, to the regulation of oxidative stress. The identification of carotenoids and phenolics from Cogshall mango made it possible to: (i) expand existing knowledge about this cultivar; and (ii) assess reference data in order to evaluate the influence of the abiotic parameters studied.Ripening induces a major oxidative stress, but it was shown that the regulation potential for oxidative stress linked to environmental conditions was, in part, driven by harvest stage. At harvest for the green-mature stage, the water deficit applied resulted in an increase in oxidative stress, with higher H2O2 and ascorbate contents for the earliest fruits, accompanied by a pronounced increase in phenolic content. However, after ripening, the stress linked to the respiration crisis eliminates the trends observed at harvest, regardless of the stage. The carotenoid pathway was modulated by water deficit with a marked accumulation of abscisic acid. Cold storage for 14 days encourages oxidative stress. After ripening at 20 °C, both harvest stage and storage temperature will modulate mango metabolism. Early fruits stored at low temperatures had low carotenoid contents and low ROS scavenging capacities, whereas later fruits had a more active defense system and a better accumulation of carotenoids. Finally, correlations between classic quality descriptors and fruit composition provided strong relationships between sugar contents and dry soluble extract and between major carotenoid contents and hue angle. However, discrepancies were observed between total carotenoids and hue angle and between titratable acidity and organic acid contents when fruits were kept in cold storage.