Ökomorphologische Konvergenz tritt auf, wenn Arten mit demselben Lebensstil unabhängig voneinander ähnliche morphologische Merkmale evolvieren. Neue Fallstudien können dabei helfen, die diesem Prozess zugrunde liegenden Mechanismen aufzuklären. Diese Arbeit befasst sich mit einigen konvergent evolvierten, langsamen, baumbewohnenden Säugetieren, d. h. zwei Linien baumlebender Faultieren, dem Zwergameisenbär, den Lorisiden, zwei Kladen ausgestorbener Lemuren, d. h. Paläopropithekiden und Megaladapis, und dem Koala. Es werden funktionsmorphologische Konvergenzen in diesen Taxa erforscht, indem ihr Humerus und ihr Femur sowie jene ihrer nah verwandten, aber ökologisch unterschiedlichen Taxa untersucht werden. Erstmals werden Knochen mittels phylogenetisch vergleichender Methoden auf vier anatomischen Ebenen, d.h. äußere Form, diaphysäre Mikrostruktur und Anatomie sowie epiphysäre Trabekelarchitektur, analysiert. Viele langsame, baumbewohnende Säugetiere teilen eine geringe kortikale Kompaktheit, was wahrscheinlich mit ihrer extrem niedrigen Stoffwechselrate und ihren biomechanischen Anforderungen zusammenhängt. Langsame, arboreale Xenarthra, d. h. baumbewohnende Faultiere und der Zwergameisenbär, weisen ein Muster unvollständiger Konvergenz für eine Reihe äußerer und innerer anatomischer Merkmale auf, was möglicherweise durch die relativ unterschiedliche Ökologie des Zwergameisenbären erklärt wird. Auf einer breiteren Säugetierskala konvergieren andere Merkmale, die möglicherweise mit der Ökologie der langsamen baumbewohnenden Lebensweise in einigen der untersuchten Taxa zusammenhängen, obwohl komplexe Muster auch durch andere evolutionäre Prozesse erklärt werden können. Nur suspensorisch lebende Taxa tragen signifikant zur Konvergenz bei. Diese Arbeit hebt die stärkere Konvergenz hervor, die sich in der inneren Struktur des Knochens widerspiegelt. / Ecomorphological convergence occurs when similar morphological traits are independently evolved by species with the same lifestyle. Novel case studies can help to elucidate the underlying mechanisms of this process. This work addresses some convergent slow arboreal mammals, i.e. two lineages of ‘tree sloths’, the silky anteater, ‘Lorisidae’, two clades of extinct lemurs, i.e. palaeopropithecids and Megaladapis, and the koala. Functional morphological convergences are searched in these taxa, studying their humerus and femur as well as those of their closely related ecologically distinct taxa. For the first time, bones are analyzed at four anatomical levels, i.e. external shape, diaphyseal microstructure and anatomy and epiphyseal trabecular architecture, through phylogenetic comparative methods. Many slow arboreal mammals share a low cortical compactness, probably related to their extremely low metabolic rate and biomechanical demands. Slow arboreal xenarthrans, i.e. ‘tree sloths’ and the silky anteater, exhibit a pattern of incomplete convergence for a set of external and internal anatomical features, possibly explained by the relatively distinct ecology of the silky anteater. On a wider mammalian scale, other traits possibly related to slow arboreal ecology converge in some of the studied taxa, although with complex patterns also explained by other evolutionary processes. Only suspensory taxa significantly contribute to convergence. This thesis highlights the stronger convergence reflected by bone internal structure. By providing potential explanations for convergence in slow arboreal mammals, the inherent complexity of this process is here emphasized.

Thèse de doctorat présenté en vue de l'obtention du doctorat en psychologie - recherche intervention, option neuropsychologie clinique (Ph.D) / Les personnes qui ont un trouble de déficit de l’attention avec/sans hyperactivité (TDAH) seraient particulièrement créatives. Toutefois, dans la littérature scientifique, cette croyance ne fait pas consensus. Bien que les personnes qui ont un TDAH présentent une grande créativité autorapportée, des résultats variables sont trouvés aux épreuves formelles de créativité (de potentiel créatif), même lorsque des variables confondantes, comme la nature hétéroclite de ces épreuves, sont prises en compte. En introduction de cette thèse, un tour d’horizon théorique sur la créativité et le TDAH est effectué et permet d’identifier un facteur de variabilité important qui a été négligé en recherche et qui pourrait masquer un lien entre la créativité et le TDAH : l’hétérogénéité du TDAH. En effet, le TDAH se découpe en différentes présentations caractérisées par des symptômes dominants (l’inattention, l’hyperactivité/l’impulsivité ou une combinaison des deux). Chacun des corrélats neurocognitifs qui sous-tendent ces symptômes contribuerait à la créativité de façons bien spécifiques, suggérant que celle-ci pourrait différer entre les présentations du TDAH. Or, bien souvent, dans les études portant sur le TDAH et la créativité, le TDAH est considéré comme un trouble homogène. L’introduction de cette thèse amène également l’idée que la relation entre la créativité et le TDAH ne devrait pas être exclusivement étudiée en recherche. Alors que la science tarde à élucider l’existence d’une telle relation, la créativité dans le TDAH pourrait potentiellement être évaluée en contexte clinique, sur une base individuelle, à l’aide de tests de créativité. Avec l’arrivée de la mouvance de la neurodiversité, il est bien possible que les personnes qui ont un TDAH soient de plus en plus intéressées à être informées au sujet des forces sur lesquelles ils peuvent prendre appui pour se réaliser comme individus. Cependant, les tests de créativité sont souvent longs à administrer ainsi qu’à corriger, faisant en sorte qu’ils s’insèrent difficilement dans un protocole d’évaluation cognitive. Même en recherche, ces tests présentent plusieurs lacunes, surtout en ce qui a trait à la mesure de l’originalité des réponses. Des méthodes de cotation populaires, comme le calcul de la rareté statistique, impliquent la prise de plusieurs décisions subjectives et nécessitent la formation de larges échantillons pour être suffisamment précises. Pour leur part, les systèmes d’accord interjuges nécessitent un grand travail de correction. Ainsi, les principaux objectifs de cette thèse sont de mieux comprendre la relation entre la créativité et le TDAH en considérant les différentes présentations de ce trouble ainsi que d’introduire et de prévalider une mesure de l’originalité qui permettrait de contourner certaines critiques des tests de créativité en recherche. Ce test pourrait aussi rendre la mesure de la créativité plus compatible aux réalités de la clinique et faciliter l’identification de forces chez les personnes qui ont un TDAH. Dans une première étude, nous voulions vérifier si la créativité varie entre les présentations les plus communes du TDAH : la présentation avec prédominance de symptômes d’inattention (TDAH-I) et la présentation combinée (TDAH-C). Nous voulions aussi explorer la relation entre la créativité, les symptômes du TDAH ainsi que l’inhibition. Les participants (n = 83, 20 hommes) étaient âgés de 18 à 51 ans (M = 26.66, É-T = 8.73) et avaient un diagnostic de TDAH-I (n = 21), de TDAH-C (n = 19) ou pas de diagnostic de TDAH (n = 43). La créativité a été évaluée à l’aide d’une mesure de l’autoperception des habilités créatives et d’un test de pensée divergente. Les résultats révèlent que le groupe TDAH-C a produit des réponses plus originales et abstraites au test de pensée divergente que le groupe contrôle. En comparaison aux autres groupes, le groupe TDAH-C a rapporté une plus grande créativité auto perçue dans le domaine de la performance. Ce score était associé aux symptômes d’hyperactivité. Ces résultats suggèrent que la créativité varie entre les présentations du TDAH et que certains symptômes seraient associés à une plus grande créativité dans des domaines spécifiques. Dans une deuxième étude, qui se voulait exploratoire, nous avons développé un nouveau test de créativité : Creo. Les réponses à Creo sont évaluées en fonction de leur niveau de nouveauté personnelle. Ce faisant, la cotation ne repose pas sur la rareté statistique dans un groupe, mais plutôt sur un calcul novateur permettant d’estimer la taille des transformations effectuées dans les réponses. Quarante-sept hommes/femmes de 16-51 ans ont participé à l’étude de prévalidation. La validité de construit a été mesurée à l’aide de tâches de pensée divergente, d’autoperception des habilités créatives, de fonctions exécutives, de fluence graphique et d’intelligence non verbale. Creo présente certaines évidences de validité de construit. Le score de nouveauté personnelle à Creo apparait conceptuellement proche de celui de l’originalité en pensée divergente. Au terme de ce travail, il apparait essentiel de considérer les différentes présentations du TDAH en recherche, car celles-ci ne présentent pas les mêmes forces créatives. Ensuite, la mesure de la nouveauté personnelle pourrait être une alternative viable aux méthodes populaires de cotation de l’originalité dans la pensée divergente. En plus d’être un test intéressant en recherche, Creo pourrait être une tâche qui s’insère facilement dans un protocole d’évaluation cognitive en clinique et comporte des attributs qui pourraient le rendre particulièrement intéressant pour l’évaluation de la créativité dans le TDAH. Les implications théoriques et cliniques de l’ensemble de nos résultats sont discutées. / People who have attention-deficit/hyperactivity disorder (ADHD) would be particularly creative. However, in the scientific literature, there is no consensus on this belief. Although people with ADHD shows high self-reported creativity, variable results are found on formal tests of creativity (tests of creative potential), even when confounding variables, such as the heterogeneous nature of these tests, are considered. In the introduction to this thesis, a theoretical overview of creativity and ADHD is carried out and identifies an important variability factor, which has been neglected in research and could mask a link between creativity and ADHD: the heterogeneity of ADHD itself. Indeed, ADHD is divided into different presentations characterized by dominant symptoms (inattention, hyperactivity/impulsivity, or a combination of both). Each of the neurocognitive correlates that underlie these symptoms may contribute to creativity in very specific ways, suggesting that it may differ between ADHD presentations. However, in studies of ADHD and creativity, ADHD is often considered to be a homogeneous disorder. The introduction of this thesis also brings the idea that the relationship between creativity and ADHD should not be exclusively studied in research. While science is slow to elucidate the existence of such a relationship, creativity in ADHD could potentially be assessed in a clinical context, on an individual basis, using creativity tests. With the arrival of the neurodiversity movement, it is quite possible that people with ADHD will be more and more interested in being informed about the strengths on which they can rely to achieve their individual fulfillment. However, creativity tests are often long to administer and correct, making them difficult to fit into a cognitive assessment protocol. Even in research, these tests have several shortcomings, especially in terms of measuring the originality of responses. Popular scoring methods, such as the calculation of statistical rarity, involve making several subjective decisions and require large samples to be sufficiently accurate. For their part, inter-rater agreement systems require a great deal of correction work. Thus, the main objectives of this thesis are to better understand the relationship between creativity and ADHD by considering the different presentations of this disorder as well as to introduce and prevalidate a measure of originality that would alleviate certain criticisms of creativity testing in research. This test could also make the measurement of creativity more compatible with clinical work and facilitate the identification of strengths in individuals with ADHD. In a first study, we wanted to verify whether creativity varies between the most common presentations of ADHD: the presentation with predominant symptoms of inattention (ADHD-I) and the combined presentation (ADHD-C). We also wanted to explore the relationship between creativity, ADHD symptoms and inhibition. Participants (n = 83, 20 men) were 18-51 years old (M = 26.66, SD = 8.73) and diagnosed with ADHD-I (n = 21), ADHD-C (n = 19) or no diagnosis of ADHD (n = 43). Creativity was assessed using a measure of self-perception of creative abilities and a divergent thinking test. The results reveal that the ADHD-C group produced more original and abstract responses to the divergent thinking test than the control group. Compared to the other groups, the ADHD-C group reported greater self-perceived creativity in the domain of performance. This score was associated with symptoms of hyperactivity. These results suggest that creativity varies between ADHD presentations and that certain symptoms may be associated with greater creativity in specific domains. In a second study, which was exploratory, we developed a new creativity test: Creo. Responses to Creo are evaluated based on their level of personal novelty. In doing so, the scoring is not based on statistical rarity in a group, but rather on an innovative calculation to estimate the size of the transformations performed in the responses produced by the participants. Forty-seven men/women aged 16-51 participated in the prevalidation study. Construct validity was measured using tasks of divergent thinking, self-perception of creative abilities, executive functions, graphic fluency, and nonverbal intelligence. Creo presents some evidence of construct validity. The personal novelty score in Creo appears conceptually close to that of originality in divergent thinking. At the end of this work, it appears essential to consider the different presentations of ADHD in research, because they do not present the same creative strengths. Second, measuring personal novelty could be a viable alternative to popular originality scoring methods in divergent thinking. In addition to being an interesting test in research, Creo could be a task that fits easily into a clinical cognitive assessment protocol and has attributes that could make it particularly interesting for the assessment of creativity in ADHD. The theoretical and clinical implications of all our results are discussed.

No description available.

This study critically examines the (UHI) effect in urban and suburban neighbourhoods of Quito, Ecuador, over a 19-year period, focusing on the interplay between atmospheric pollution and urban/ suburban temperature. Utilizing Empirical Dynamic Modeling(EDM) and Convergent Cross-Mapping (CCM), this study dives into the nonlinear dynamics of environmental factors, a method that traditional linear models fail to address effectively.The results unveil a consistent and strong positive correlation across various neighbourhoods, with temperature fluctuations indicating a typical UHI effect. This is most noticeable in urbanized areas where the temperature is significantly higher due to dense infrastructure and reduced greenery, a pattern that diminishes as one moves towards the outskirts. Specifically, pollutants like PM2.5 exhibit a non-uniform positive correlation, suggesting their collective increase or decrease across different regions, whereas CO shows a very slight and inconsistent inverse relationship across locations. The causal analysis further substantiates a significant interaction between PM2.5 concentrations and temperature, with the data revealing a reciprocal predictive capacity between these variables. The CCM analysis, through its graphical representation of predictive skills, confirms the causal effect of PM2.5 on urban temperature, marking an essential contribution to understanding the UHI effect and its implications for urban environmental dynamics. This study provides a comprehensive overview of the UHI phenomenon, highlighting the intricate relationship between urbanization, atmospheric pollution, and climate. The findings emphasize the necessity for urban planning and policy to consider these complex interactions to mitigate the effects of climate change on urban environments.

This study was conducted in order to assess the effects of creative stimulation in early childhood. The quantitative quasi-experimental study was set out to test a target group of 8 children in grade R, ranging in age from five to six years, to determine the importance of stimulation and intervention of creativity from a young age. A pre-test, evaluated the initial level of each child’s creative skills in fluency, flexibility and originality. This was followed by selecting one class as the experimental group and another class, from the same demographical location, as the control group. The experimental group underwent a six-week intervention programme which focused on the primary concepts in each area of fluency, flexibility and originality. Both groups continued with their normal school learning programmes. The results indicate that the impact of stimulation on young children was significant and that there was a great difference in the abilities and understanding of concepts in those children whohad been stimulated. / Teacher Education / M. Ed. (Psychology of Education)

The concept of biodiversity – the phenotypic and genotypic variation among organisms – is central to conservation biology. There is growing recognition that biodiversity does not exist in isolation, but rather is intrinsically and evolutionarily linked to cultural diversity and indigenous knowledge systems. In Canada, caribou (Rangifer tarandus) occupy a central place in the livelihoods and identities of indigenous people and display substantial variation across their distribution. However, quantifying caribou intraspecific variation has proven challenging. Interdisciplinary approaches are necessary to produce effective species characterizations and conservation strategies that acknowledge the interdependent relationships between people and nature in complex social-ecological systems. In this dissertation I use multiple disciplinary traditions to develop comprehensive and united representations of caribou variation through an exploration of population genetics, phylogenetics, traditional knowledge, language, and visual approaches in the Sahtú region of the Northwest Territories, Canada. First, I examine caribou variation through analysis of population genetics and the relationships Dene and Métis people establish with animals within bioculturally diverse systems. Next, I focus on how the Pleistocene glacial-interglacial cycles have shaped the current patterns of caribou phylogeographic lineage diversification. Finally, I explore how art can be used to facilitate cross-cultural collaboration and externalize the unique heterogeneity of biocultural diversity. The results demonstrate a broad scale understanding of the distribution, spatial organization, and the degree of differentiation of caribou populations in the region. I found evidence for caribou population differentiation that corresponds to the caribou types recognized by Dene people: tǫdzı “boreal woodland caribou,” ɂekwę́ “barren-ground caribou,” and shúhta ɂepę́ “mountain caribou.” Phylogenetic results reveal that in their northern margin the boreal ecotype of woodland caribou evolved independently from the northern Beringian lineage in contrast with southern boreal caribou which belong to the sub-Laurentide refugia lineage. In addition, I demonstrate how art can be used improve communication, participation, and knowledge production among interdisciplinary research collaborations and across language and knowledge systems. A collaborative process of research that facilitates łeghágots'enetę “learning together” has the potential to produce sustainable conservation solutions, develop efficient and effective wildlife management policies, and ensure caribou remain an important part of the landscape. / February 2017

To avoid dangerous climate change a massive reduction in greenhouse gas emissions is required in a relative short time span. However, as development is moving in the wrong direction, there appears to be great inertia in changing activities. This dissertation’s overarching purpose is, from an institutional perspective, to advance the understanding of greenhouse gas-related inertia, as well as change, in industrial agri-activities. This purpose is addressed in four individual but related papers and an introductory chapter. A case study methodology is utilized to advance knowledge regarding greenhouse gas-related inertia and change. Two change initiatives involving the Swedish Board ofAgriculture, the designated expert authority on agricultural matters, were chosen and explored with qualitative methods. The first case consisted of a project to create at an Action Plan, a policy suggestion regarding strategies to reduce emissions from agriculture. The second case focused on the Swedish Board of Agriculture’s co-owned agricultural extension service, Greppa Näringen. More specifically, the case consisted of the provision of climate advice to farmers. The analyses of the initiatives focused on assessing, discussing and explaining the types of change advanced within them. The papers show how and why convergent rather than divergent change was pursued, describing different mechanisms generating this inertia. / För att undvika farliga klimatförändringar krävs massiva minskningar av växthusgasutsläpp på relativt kort tid. Detta kan inte uppnås utan omfattande förändringar av utsläppsintensiva aktiviteter. Det förefaller dock finnas en stor tröghet avseende detta, eftersom utvecklingen går i fel riktning. Såväl tröghet som förändring kan analyseras på olika nivåer, och den industriella nivån är speciellt relevant eftersom industriella aktiviteter bidrar med stora utsläpp. I detta sammanhang är primärproduktion av livsmedel av relativ betydelse, både med anledning av utsläppens storlek och produktionens betydelse för mänsklighetens överlevnad. För att förstå de ofta värdeladdade och idédrivna beteendena involverade i miljörelaterade förändringsprocesser använder jag mig av institutionell teori, en icke-reduktionistisk organisationsteori innehållande ett antal, i sammanhanget passande begrepp. Jag kombinerar institutionell teori med en positionering i det ”starka” hållbarhetsparadigmet, vilket ger ett analytiskt ramverk som betonar betydelsen av divergent, snarare än konvergent, förändring av industriell praktik. Följaktligen är denna avhandlings syfte att, ur ett institutionellt perspektiv, öka förståelsen av tröghet och förändring, relaterat till växthusgasutsläpp och industriella jordbruksaktiviteter. Syftet adresseras i fyra individuella men relaterade papper och en inledande kappa. Kappan presenterar det teoretiska ramverket, metoden, en översikt över artiklarna och en avslutande diskussion av artiklarnas sammanlagda bidrag i relation till litteraturen och avhandlingens syfte. Avhandlingen använder en fallstudie metodologi för att öka förståelsen av tröghet och förändring relaterat till växthusgasutsläpp. Två förändringsinitiativ relaterade till Statens jordbruksverk, expertmyndigheten på jordbruksområdet, valdes ut och utforskades med kvalitativa metoder. Bägge dessa initiativ riktade sig specifikt emot primärproduktion, där de största utsläppen sker. Det första fallet utgjordes av ett projekt för att skapa en handlingsplan: ett förslag på strategier för att reducera utsläpp från jordbruket. Det andra fallet fokuserade på Jordbruksverkets rådgivningsorganisation, Greppa Näringen, och utgjordes av klimatrådgivning riktat mot lantbrukare. Analysen av fallen sökte bedöma, diskutera och förklara den typ av förändring som eftersträvades. Resultaten har beskrivits i de fyra artiklarna, där de två första koncentrerade sig på studiet av handlingsplanen och de två senare på klimatrådgivningen. Artiklarna visar hur och varför som konvergent, snarare än divergent, förändring eftersträvades, genom att beskriva olika mekanismer som skapar denna tröghet. Konvergent förändring inbegriper ett fokus på effektivitet eller rådande politiska mål snarare än att minska förekomsten av utsläppsintensiva aktiviteter. I diskussionen av artiklarnas sammanlagda resultat föreslås att förändringsinitiativen bidrar till tröghet inom industrin genom att påverka öppenheten och motivationen gentemot divergent förändring hos andra aktörer. Avhandlingen bidrar till hållbarhetsfältet genom att ge en institutionell analys av tröghet och förändring på industriell nivå, vilket visar på hur begreppen konvergent/divergent förändring kan användas för att utforska hållbarhetsfrågor. Genom detta exempel kan förändringsprocesser i andra industrier inbegripande andra hållbarhetsfrågor förstås bättre. Utöver detta bidrar avhandlingen till institutionell teori, mer specifikt till diskussionen rörande hållbart entreprenörskap och institutionella logiker. Det förstnämnda bidraget inkluderar förbättrad förståelse av möjliggörande såväl som institutionellt entreprenörskap i fält karakteriserade av institutionell komplexitet, medan det sistnämnda utgörs av konceptualiseringen av konkurrerande institutionella logiker och deras inflytande på översättning.

Les anomalies du tube neural (ATN) sont des malformations congénitales parmi les plus fréquentes chez l’humain en touchant 1-2 nouveau-nés par 1000 naissances. Elles résultent d’un défaut de fermeture du tube neural pendant l’embryogenèse. Les formes les plus courantes d'ATN chez l'homme sont l'anencéphalie et le spina-bifida. Leur étiologie est complexe impliquant à la fois des facteurs environnementaux et des facteurs génétiques. Un dérèglement dans la signalisation Wnt, incluant la signalisation canonique Wnt/β-caténine et non-canonique de la polarité planaire cellulaire (PCP), peut causer respectivement le cancer ou les anomalies du tube neural (ATN). Les deux voies semblent s’antagoniser mutuellement. Dans cette étude, nous investiguons les rôles de Lrp6 et deANKRD6, entant qu’interrupteurs moléculaires entre les deux voies de signalisation Wnt, et CELSR1, en tant que membre de la PCP, chez la souris mutante Skax26m1Jus, générée par l’agent mutagène N-Ethyl-N-Nitrosuera, et dans une cohorte de patients humains ATN. Pour Lrp6, nous avons démontré que Skax26m1Jus représente un allèle hypermorphe de Lrp6 avec une augmentation de l’activité de la signalisation Wnt/canonique et une diminution de l’activité JNK induite par la voie PCP. Nous avons également montré que Lrp6Skax26m1Jus interagit génétiquement avec un mutant PCP (Vangl2Lp) où les doubles hétérozygotes ont montré une fréquence élevée d’ATN et des défauts dans la polarité des cellules ciliées de la cochlée. Particulièrement, notre étude démontre l'association des nouvelles et rares mutations faux-sens dans LRP6 avec les ATN humaines. Nous montrons que trois mutations de LRP6 causent une activité canonique réduite et non-canonique élevée. Pour ANKRD6, nous avons identifié quatre nouvelles et rares mutations faux-sens chez 0,8% des patients ATN et deux chez 1,3% des contrôles. Notamment, seulement deux, des six mutations validées (p.Pro548Leu et p.Arg632His) ont démontré un effet significatif sur l’activité de ANKRD6 selon un mode hypomorphique. Pour CELSR1, nous avons identifié une mutation non-sens dans l'exon 1 qui supprime la majeure partie de la protéine et une délétionde 12 pb. Cette perte de nucléotides ne change pas le cadre de lecture et élimine un motif putatif de phosphorylation par la PKC " SSR ". Nous avons également détecté un total de 13 nouveaux et rares variants faux-sens qui avaient été prédits comme étant pathogènes in silico. Nos données confirment le rôle inhibiteur de Lrp6 dans la signalisation PCP pendant la neurulation et indiquent aussi que les mutations faux-sens identifiées chez LRP6 et ANKRD6 pourraient affecter un équilibre réciproque et un antagonisme très sensible à un dosage précis entre les deux voies Wnt. Ces variants peuvent aussi agir comme facteurs prédisposants aux ATN. En outre, nos résultats impliquent aussi CELSR1 comme un facteur de risque pour les anomalies du tube neural ou l’agénésie caudale. Nos résultats fournissent des preuves supplémentaires que la voie de signalisation PCP a un rôle pathogène dans ces malformations congénitales et un outil important pour mieux comprendre leurs mécanismes moléculaires. / Neural tube defects (NTDs) are among the most common congenital malformations in humans affecting 1–2 infants per 1000 births. NTDs are caused by failure of the neural tube to close during embryogenesis. The most common forms of NTDs in humans are anencephaly and spina bifida. Their etiology is complex implicating environmental and genetic factors. Wnt signaling has been classified as canonical Wnt/ β-catenin dependent or non-canonical planar cell polarity (PCP) pathway. Misregulation of either pathway is linked mainly to cancer or neural tube defects (NTDs) respectively. Both pathwaysseem to antagonize each other. In this study, we investigate the role of Lrp6andANKRD6 as molecular switches between both Wnt pathways as well as CELSR1 as PCP member, in a novel ENU mouse mutant of Lrp6 (Skax26m1Jus) and in human NTDs. For Lrp6, we demonstrate that Skax26m1Jus represents a hypermorphic allele of Lrp6 with increased Wnt canonical and abolished PCP-induced JNK activities. We also show that Lrp6Skax26m1Jusgenetically interacts with a PCP mutant (Vangl2Lp) where double heterozygotes showed an increased frequency of NTDs and defects in cochlear hair cells’ polarity. Importantly, our study also demonstrates the association of rare and novel missense mutations in LRP6 that is an inhibitor rather than an activator of the PCP pathway with human NTDs. We show that three LRP6 mutations in NTDs led to a reduced Wnt canonical activity and enhanced PCP signaling. For ANKRD6: We identified four rare missense mutations in 0.8% of the NTD patients and 2 rare missense mutations in 1.3% of the controls. Notably, when all 6 mutations were validated, only two mutations identified in NTD patients, p.Pro548Leu, p.Arg632His, significantly altered DIVERSIN activity in Wnt signaling assays in a hypomorphic fashion. For CELSR1: We identified one nonsense mutation in exon 1 of CELSR1 that truncates the majority of the protein in one NTD patient and one in-frame 12 bp deletion that removes a putative PKC phosphorylation“SSR” motif in one caudal agenesis patient. We also detected a total of 13 novel missense variants in 12 patients (11 NTDs and 1 caudal agenesis) that were predicted to be pathogenic in silico. Our data confirm an inhibitory role of Lrp6 in PCP signaling in neurulation and indicate that rare missense mutations in LRP6 and ANKRD6 could affect a balanced reciprocal and a highly dosage sensitive antagonism between both Wnt pathways in neurulation and act as predisposing factors to NTDs in a subset of patients. Also, our findings implicate CELSR1 as a risk factor for NTDs or caudal agenesis. Our findings provide additional evidence for a pathogenic role of PCP signaling in thesemalformations and an important tool for better understanding their molecular mechanisms.

Les furocoumarines sont des composés phénoliques impliqués dans la défense contre les herbivores. Ces molécules sont majoritairement décrites dans quatre familles botaniques, notamment les Rutaceae, dont font partie les agrumes. Ces molécules sont phototoxiques ce qui peut poser des problèmes pour leur utilisation comme par exemple en cosmétique ou en phytothérapie. D’autre part, en cas d’ingestion par exemple via la consommation de jus de certains agrumes, elles ont responsables de l’inhibition d’enzymes de détoxication comme le CYP3A4 humain. Cela peut conduire à des surdosages médicamenteux connus sous le nom d’Effet Pomelo. Ce travail de thèse a consisté à réfléchir et à développer, des outils qui permettront de générer de manière ciblée des variétés de pomelo qui ne produisent plus de furocoumarines. Nous avons abordé l’ensemble des étapes essentielles pour la mise en place d’une stratégie global : i) des méthodes reproductibles ont été développées pour la production de protoplastes et de cultures cellulaires de pomelo Star Ruby ; ii) des conditions de transformation de protoplastes par électroporation ont également été mises au point ; iii) finalement, pour inhiber de manière spécifique la voie de biosynthèse des furocoumarines, nous avons choisi de mettre en œuvre une approche d’édition de génome en utilisant une méthodologie CRISPR/Cas9. La mise au point de la méthode a été réalisée avec un gène codant pour une umbelliferone 6-dimethylallyl transférase. Les résultats obtenus indiquent que la stratégie est envisageable. Pour renforcer la stratégie CRISPR/Cas9, nous avons mis en œuvre une démarche d’identification de gènes cibles additionnels. En utilisant une approche de data mining de bases de données génomiques et transcriptomiques nous avons identifié 18 séquences candidates, potentiellement impliquées dans la voie de biosynthèse des furocoumarines. L’expression hétérologue des protéines correspondantes et leur caractérisation fonctionnelle a permis de montrer que CYP706J12 est en mesure de métaboliser l’hérniarine, une coumarine. Ce résultat apporte des éléments pour émettre des hypothèses sur l’évolution convergente de la synthèse des coumarines et des furocoumarines chez les végétaux supérieurs. / Furanocoumarins are phenolic compounds involved in defense against herbivores. These molecules are mainly described in four botanical families. Rutaceae, one of those families, includes Citrus species. Furanocoumarins are phototoxic compounds, which can be problematic for their use in cosmetics or in phytotherapy. Furanocoumarin ingestion via citrus juice consumption, may inhibit human enzymes of detoxification, such as human CYP3A4. This can lead to drug overdoses known as the “Grapefruit Juice Effect”. This work consisted in the development of tools that will allow to generate new varieties of pomelo that no longer produce furanocoumarins by targeted genome edition. We have covered the essential steps for the implementation of a global strategy: i) reproducible methods have been developed for the production of protoplasts and cell cultures of Star Ruby grapefruit; ii) conditions for protoplast transformation by electroporation have also been developed; iii) finally, to specifically inhibit the furanocoumarin biosynthetic pathway, we chose to implement a genome editing approach using a CRISPR / Cas9 methodology. The development of the method was carried out with a gene encoding umbelliferon 6-dimethylallyltransferase. The results obtained indicate that the strategy is feasible. To strengthen the CRISPR / Cas9 strategy, we implemented a method to identify additional target genes. Using a data mining approach of available genomic and transcriptomic databases we identified 18 candidate sequences potentially involved in the furanocoumarin biosynthetic pathway. Heterologous expression of the corresponding proteins and their functional characterization made it possible to show that CYP706J12 is able to metabolize herniarin (a coumarin). This result provides elements to hypothesize about the convergent evolution of coumarin and furanocoumarin synthesis in higher plants.

A síntese de peptídeos em fase sólida passo a passo (SPFS) tem sido aplicada com sucesso na preparação de peptídeos curtos, médios e de determinados sequências contendo mais de 30 resíduos. Entretanto, esta apresenta problemas e limitações que podem ser contornados pela síntese convergente de peptídeos em fase sólida (SCPFS) que se baseia na condensação entre fragmentos peptídicos Nα-acilados protegidos em suas cadeias laterais (doadores de acila) a fragmentos protegidos ligados a um suporte polimérico (receptores de acila). Além de desenvolver outros projetos enfocados na síntese de peptídeos ou no uso de sintéticos para o estudo de peptídeos biologicamente ativos ou proteinas, o nosso grupo de pesquisa tem se dedicado a estudar o emprego de temperaturas altas em SPFS. O objetivo final é propor protocolos ágeis alternativos aos empregados classicamente. Neste trabalho nos propusemos a investigar alguns aspectos da SCPFS e a explorar a possibilidade de agilizá-Ia a 60°C. Para tanto, empregamos como modelos a colecistocinina-33 humana (hCCK-33) não sulfatada e o análogo [Gln1]-gomesina. As seqüências destes peptídeos foram divididas em: doadores de acila (fragmentos central e N-terminal da hCCK-33 não sulfatada de 11 e de 5 resíduos, respectivamente, e N-terminal de 8 resíduos do [Gln1]-gomesina) e receptores de acila (fragmentos C-terminais da hCCK-33 não sulfatada de 17 resíduos e do [Gln1]-gomesina de 10 resíduos). As peptidil-resinas correspondentes foram sintetizadas manualmente por SPFS passo a passo e caracterizadas por análise de aminoácidos para determinação de seus graus de substituição. Suas propriedades de solvatação em diferentes sistemas de solventes foram também examinadas. Análises por RP-HPLC e LC/ESI-MS dos peptídeos brutos obtidos após clivagem das resinas e desproteção total permitiram avaliar as sínteses realizadas. Os doadores de acila foram então gerados a partir das peptidil-resinas empregando procedimentos conhecidos (catálise por DBU ou NaOH) e um proposto por nós (assistência por íons metálicos). Finalmente, os acoplamentos entre os doadores e receptores de acila foram realizados a 37 e 60°C empregando sistemas de solventes adequados à solvatação dos receptores de acila e diferentes reagentes acopladores. As peptidil-resinas alongadas foram analisadas em seu conteúdo de aminoácidos e submetidas à clivagem e desproteção total para liberação dos peptídeos brutos correspondentes. Estes foram submetidos à análise comparativa usando RP-HPLC e LC/ESI-MS. Os resultados obtidos neste primeiro trabalho que emprega alta temperatura na SCPFS demonstraram que: 1) o conhecimento do grau de solvatação das peptidil-resinas auxilia na escolha do sistema de solventes a ser empregado na geração dos doadores de acila (desligamento dos peptídeos protegidos correspondentes) e nos seus acoplamentos aos receptores de acila; 2) a geração de doadores de acila a partir de peptidil-KOR não é trivial como sugere a literatura (o fragmerto 6-19 da hCCK-33 na forma protegida não foi obtido) e deve ser melhor estudada. O tamanho e a seqüência peptídica parecem estar diretamente relacionados à eficiência do processo; 3) o uso de alta temperatura agiliza o processo; 4) a geração de doadores de acila a partir de peptidil-2-CI-Trt empregando 1%TFA em DCM e misturas AcOH:TFE:DCM é simples e eficiente; 5) o uso combinado de DMF, do agente acoplador TBTU e de 60°C levou à agilização dos acoplamentos convergentes realizados, fornecendo os peptídeos desejados com boa qualidade em tempos relativamente menores; 6) vantagens e desvantagens da SCPFS em alta temperatura devem ser melhor avaliadas; 7) a SCPFS também apresenta limitações e problemas a serem contornados, o que demanda exploração sistemática empregando seqüências peptídicas e resinas variadas. / Stepwise solid-phase peptide synthesis (SSPPS) has been applied successfully for the preparation of most peptides containing up to 30 residues. However, it presents problems and limitations. Convergent soIid-phase peptide synthesis (CSPPS) can overcome part of them. This methodology is based on the synthesis of peptide segments by SSPPS followed by their condensations: the Nα- acylated protected segments act as acyl donors and the protected segments bound to the resin as acyl receptors. When the sequence is completed this is detached from the resin and fully deprotected to give the crude peptide. Besides developing other projectsfocused on peptide synthesis itself or on the use of synthetics to study biologically active peptides or proteins, we have systematically examined solid-phase peptide synthesis at elevated temperature. The aim of the present work was to investigate different aspects of convergent solid-phase peptide synthesis and examine the possibility to improve it at 60°C. Thus, unsulfated human cholecystokinin-33 and [Gln1]-gomesin were divided in three and two fragments, respectively. In the first case, the acyl donors were built-up by SSPPS on Kaiser oxime resin while in the second peptide elongation was done on 2-CI-Trt resin. The acyl receptor was synthesized and kept on the MBHA resin. The synthetic process was evaluated through characterization of every peptidyl-resin by amino acid analysis and of each crude peptide obtained from resin cleavage/full deprotection by RP-HPLC and LC/ESI-MS. The swelling degrees of the peptidyl-resins were determined in various solvents or mixtures of high boiling points. The peptidyl-KOR and peptidyl-2-CI-Trt were then submitted to peptide detachment under a few experimental conditions in order to release the Nα-acyl protected peptides (the acyl donors). Finally, their couplings with the acyl receptors were carried-out at 37 and 60°C in solvents or mixtures suitable for peptidyl-resin solvation containing specific coupling agents. The resulting peptidyl-resins were isolated, dried and submitted to HF treatment to release the corresponding unprotected crude peptides, which were analysed by RP-HPLC and LC/ESI-MS. The results found indicated that: 1) the knowledge of the swelling properties of the peptidyl-resins in different solvents systems is very useful in SCPFS. Indeed, it may guide the selection of experimental conditions to be used in peptide detachment from KOR and 2-CI-Trt and in segment condensation at elevated temperature, 2) peptide detachment from KOR is not as trivial as described (it was impossible to release hCCK-33 fragment 6-19 in its protected form). Further studies are certainly required to improve it. It seems that the size and the sequence are strictly related to the process efficiency, 3) high temperature can improve it, 4) peptide detachment from 2-CI-Trt is as simple as described, 5) combination of DMF as solvent, TBTU as coupling agent and 60°C was suited for the segment couplings studied: the reactions were completed in relatively short times and crude peptides of good quality were obtained, 6) this is the first attempt to carry-out CSPFS at elevated temperature, thus its advantages and disadvantages must be studied, 7) CSPPS also presents problems and limitations to overcome. Such task requires further investigation using various resins and peptide sequences.