Orientadora: Kathia Fernandes Lopes Pivetta / Banca: Regina Maria Monteiro de Castilho / Banca: Fabíola Vitti Moro / Resumo: A palmeira Syagrus oleracea (Mart.) Becc é a única espécie produtora de palmito amargo e desperta grande interesse no paisagismo brasileiro, porém ainda é pouco estudada. A germinação lenta e desuniforme das sementes acarretam problemas na propagação dessa espécie, dificultando principalmente, a produção de mudas em escala comercial. Desta forma, o objetivo deste trabalho foi descrever os aspectos morfológicos dos diásporos e das plântulas, bem como, estudar o efeito do substrato e da escarificação mecânica na germinação de sementes de S. oleracea. Para os estudos da morfologia, efetuou-se a semeadura de 100 diásporos em caixas de plástico (50 x 22 x 16 cm), contendo uma camada de 10 cm do substrato vermiculita média umedecida, sendo retiradas amostras representativas de casa fase do processo germinativo. As amostras, a face externa, interna e o embrião dos diásporos foram documentados com auxílio de câmara clara acoplada ao estereomicroscópio. Para o estudo do efeito do substrato e da escarificação mecânica, o delineamento foi inteiramente casualizado em esquema fatorial 6X2 (seis substratos: vermiculita, areia, Plantmax®, Turfa®, fibra de coco e composto de poda de árvore, combinados sem ou com escarificação mecânica do endocarpo) e 4 repetições de 25 diásporos. Anotou-se, a cada 5 dias, durante 90 dias, o número de sementes germinadas adotando como critério de germinação o aparecimento da primeira folha. Determinou-se porcentagem de germinação (%), Índice de Velocidade de Emergência (IVE), área foliar (cm2), comprimento de raiz (cm), massa seca de folha (g) e massa seca de raiz (g). As médias foram comparadas pelo teste de Tukey, a 5 %. Verificou-se que as sementes são albuminosas, com endosperma ruminado e de consistência dura ocupando quase todo o interior do diásporo; o embrião... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Syagrus oleracea (Mart.) Becc palm is the only species producer of bitter palm heart and arouses great interest in the Brazilian landscape, but is still little studied. The slow and uneven germination of seeds cause problems in the propagation of this species, mainly the seedlings production on a commercial scale. The objective of this study was to describe the disseminule and seedling morphology and to study the effect of substrate and mechanical scarification on germination of S. oleracea seed. For study the morphology, was made the sowing of 100 disseminules in plastic boxes (50 x 22 x 16 cm) containing a layer of 10 cm medium vermiculite and samples representing each phase of the germination process. The samples, the external and internal face, and embryo of the seeds were documented using the help of a clear camera coupled to a stereomicroscope. For study the effect of substrate and mechanical scarification, the design was completely randomized in factorial scheme (6x2) with 4 replications of 25 disseminules. Noted to every 5 days during 90 days the number of germinated seed adopting as criterion for germination the appearance of the first leaf. It was determined percentage of germination (%), speed of emergence index (IVE), leaf area (cm2), root length (cm), leaf dry mass (g) and root dry mass (g). The averages were compared by Tukey test at 5%. The results showed that the seeds are albuminous type, ruminal endosperm with hard consistency occupying almost the entire interior of the disseminule; the embryo is lateral, peripheral, straight and little differentiated; the seed germination is remote tubular type. It was concluded that seeds without scarification in vermiculite, germinated faster and had higher percentage of germination (65%) and greater length of root (16.55 cm), leaf dry mass (5.07 g) and dry mass root (12.41 g). / Mestre

Made available in DSpace on 2014-06-11T19:29:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-18Bitstream added on 2014-06-13T19:39:02Z : No. of bitstreams: 1 regis_jta_me_ilha.pdf: 771444 bytes, checksum: abaa5d900580a22b13d9cbb9beeeb58f (MD5) / O maracujá-doce é a segunda espécie de maracujazeiro mais plantada no Brasil. O maracujazeiro doce tem como vantagem sua resistência à morte prematura. Este trabalho teve como objetivo avaliar a calagem, o cultivo orgânico e mineral, na fase de formação de mudas de maracujazeiro doce (Passiflora alata Ait.) bem como no desenvolvimento destas mudas no campo. O experimento foi desenvolvido e conduzido no viveiro e no campo da Fazenda de Ensino Pesquisa e Extensão no município de Selvíria-MS. No viveiro, o experimento foi em blocos ao acaso, com oito tratamentos (adubações mineral , orgânica e calcário), quatro repetições e oito mudas úteis por parcela e no campo delineamento foi em blocos ao acaso, com oito tratamentos, três repetições e duas plantas por repetição. Foram avaliados no viveiro, a porcentagem de germinação, número de folhas, altura da planta, comprimento radicular, massa da matéria seca da parte aérea e massa da matéria seca das raízes. Na análise química foram determinadas as concentrações de macronutrientes (N, P, K, S, Ca e Mg) e de micronutrientes (Zn, Mn, Cu, Fe e B) na parte aérea e na raiz. No campo foram avaliados o diâmetro do tronco e a altura da planta. Com base nos resultados obtidos nas condições do experimento conclui-se que: Experimento no Viveiro: a) a adição de esterco bovino no substrato propiciou mudas com maior qualidade, especialmente se acompanhada de adubação mineral; b) O substrato com os tratamentos 8 (SFS + FTE-BR12 + esterco bovino + calcário), 4 (SFS + FTE-BR12 + esterco bovino) e 2 (esterco bovino) propiciou maior desenvolvimento das mudas; c) As melhores concentrações de nutrientes na massa seca da parte aérea e na raiz foram as obtidas no tratamento 8 (SFS + FTE-BR12 + esterco bovino + calcário) resultando em mudas vigorosas de maracujá doce. Experimento no Campo: d)... / The sweet passion fruit is the second most planted in Brazil. The sweet passion fruit has the advantage of its resistance to premature death. This study aimed to evaluate the liming, organic farming and mineral during the formation of sweet passion fruit (Passiflora alata Ait.) As well as the development of these seedlings in the field. The experiment was conducted in the nursery in the farm of instruction, research and extension in Selviria-MS. The design was randomized blocks with eight treatments ( mineral fertilizer, lime and organic), four repetitions and eight plants useful per parcel and field design was a randomized block with eight treatments, three replications and two plants per replicate . Was evaluated in the nursery germination percentage, leaf number, plant height and root length, dry matter and shoot dry mass of roots. In the chemical analysis were determined the concentrations of macronutrients (N, P, K, S, Ca and Mg) and micronutrients (Zn, Mn, Cu, Fe and B) in shoots and roots. In the field was evaluated for plant height and trunk diameter. Based on the results obtained in the experiment can be concluded that: Experiment in the Nursery: a) the addition of manure in the substrate provided with the best quality seedlings, especially if accompanied by mineral fertilizer b) The substrate with the treatments 8 ( SFS + FTE-BR12 + manure + lime), 4 (SFS + + FTE BR12-manure) and 2 (manure) causes greater development of the seedlings; c) the best nutrient concentrations in shoot dry mass and root treatment was 8 (SPS + FTE-BR12 + manure + lime) to produce vigorous seedlings of sweet passion. Field experiment: d) Association of organic manure (farmyard manure), mineral fertilizer or lime in the substrate was positive for growth and development of plants in the field

No description available.

Este experimento avaliou, em casa de vegetação, o desenvolvimento de mudas de cafeeiro produzidas em tubetes, sob o efeito de malhas utilizadas para sombreamento. Os tratamentos utilizados foram a malha negra 50%, conhecida comercialmente como “sombrite” ou “tela preta”, considerada padrão para o desenvolvimento destas mudas, e malhas termo-refletoras com quatro diferentes percentagens de atenuação da radiação solar, sendo as malhas 40%, 50%, 60% e 70%. O delineamento experimental adotado foi em blocos casualizados contendo os 5 tratamentos, com 4 repetições, totalizando-se assim 20 parcelas. As parcelas foram representadas por 20 bancadas, cada qual contendo fechamento superior com um tipo de malha para sombreamento, e também fechamento nas laterais, atenuando a radiação solar lateral. Cada parcela foi composta por 175 mudas, sendo 161 para bordadura, e 14 para avaliações. As irrigações, realizadas diariamente, foram implementadas com a utilização de uma barra motorizada semi-automatizada que se deslocava longitudinalmente na casa de vegetação em ambos os sentidos. A lâmina desejada era ajustada de acordo com a velocidade de deslocamento da barra que era regulada por meio de um inversor de freqüência, responsável por este controle. Para monitorar o microclima, foi instalado interiormente a cada parcela um psicrômetro não ventilado e de tempos em tempos foram realizadas medidas de radiação solar global, fotossinteticamente ativa e o saldo de radiação (SR), estabelecendo-se relações de transmissividade global (TRG) e transmissividade fotossinteticamente ativa (TRFA). As variáveis fisiológicas utilizadas para avaliar o desenvolvimento das mudas foram área foliar, altura das plantas, diâmetro do caule, e, ao final do experimento, foram realizadas análises de matéria seca da parte aérea, do sistema radicular e matéria seca total. A avaliação dos dados psicrométricos mostrou que a temperatura do ar pouco variou nas parcelas, assim como a umidade relativa do ar. Com relação a TRG e TRFA, verificou-se que malhas com menor atenuação da radiação solar apresentaram em geral maior transmissividade, conforme esperado. Para a variável saldo de radiação, a presença de interferências ambientais inviabilizou a maior parte dos dados, verificando-se em apenas parte deles uma tendência de maior SR nas malhas 40% e 50%. A avaliação das variáveis fisiológicas mostrou que a área foliar não apresentou diferença significativa entre os tratamentos. Já para altura da planta e diâmetro do caule, verificou-se que as mudas produzidas sob as malhas termo-refletoras 40% e 50% foram superiores àquelas produzidas sob malha negra 50% e malhas termo-refletoras 60% e 70%, respectivamente. Nas avaliações de matéria seca, verificou-se que as mudas produzidas sob as malhas termo-refletoras 40% e 50%, e malha negra 50% acumularam mais matéria seca comparativamente àquelas produzidas sob malhas termo-refletoras 60% e 70%. Assim, nas condições em que desenvolveu-se o experimento, concluiu-se que as malhas termo-refletoras 40% e 50% e negra 50% apresentaram melhores resultados que as malhas termo-refletoras 60% e 70%. / This experiment evaluated, in greenhouse conditions, the development of coffee seedlings produced in plastic tubes, under the effect of screens used for shading. The treatments were black screen 50%, known commercially as "sombrite" or as "black screen", considered standard for the development of these seedlings, and thermo-reflective screens with four different percentages of attenuation of the solar radiation, being meshes 40%, 50%, 60%, and 70%. The adopted experimental delineation was randomized blocks with 5 treatments and 4 replicates, making up 20 parcels. The parcels were represented by 20 benches; each one with superior closing system with one type of screen, and also side closing system, attenuating the side solar radiation. Each parcel was composed by 175 seedlings, from which 161 were used as a border, and 14 used for the evaluations. The irrigation, daily carried out, was implemented with the use of a semi-automated motorized bar that dislocated longitudinally along the greenhouse in both directions. The desired water amount was set in accordance to the bar displacement speed that was established by means of a frequency inverter, responsible for this control. To monitor the microclimate, one psicrometer was installed inside each parcel and, from time to time, global solar radiation, photosynthetically active radiation, and net radiation (SR) measures were taken, establishing, this way, relations of global transmissivity (TRG) and photosynthetically active transmissivity (TRFA). The physiological variables used to evaluate the development of the seedlings were leaf area, seedlings height, and stalk diameter. Analyses on the dry matter of aerial part and root system and total dry matter were carried out at the end of the experiment. The evaluation of the psicrometers data showed that the temperature of air gently varied in the parcels, as well as the air relative humidity. Relating to TRG and to TRFA, it was verified that screens with less attenuation of the solar radiation presented higher transmissivity in general, as expected. For the variable net radiation, the presence of environment interference made most data impracticable, verifying a partial trend of higher SR in the screens 40% and 50%. The evaluation of the physiological variables showed that the leaf area did not present significant difference among the treatments. Yet, it was verified that, for seedlings height and stalk diameter, the seedlings produced under thermo-reflective screens 40% and 50% were superior to those produced under black screen 50% and thermo-reflective screen 60% and 70%. It was also verified that, for the evaluations of dry matter, the seedlings produced under thermo-reflective screens 40% and 50%, and black screen 50% comparatively accumulated more dry matter than those produced under thermo-reflective screens 60% and 70%. Thus, under the conditions where the experiment was carried out, it can be concluded that the thermo-reflective screens 40% and 50% and black screen 50% presented better results than the thermo-reflective screens 60% and 70%.

Os crustáceos estão entre os invertebrados marinhos mais diversos e tendem a se associar com outros organismos a fim de encontrar abrigo, oferta de alimento e um lugar seguro para reprodução. Aspectos reprodutivos como fecundidade, tamanho dos embriões e energia investida na reprodução são os principais parâmetros para a compreensão da história natural de uma espécie e/ou população. Assim, esse trabalho foi desenvolvido no sentido de investigar tais parâmetros e a influência do tipo de substrato ocupado. A espécie utilizada como modelo de estudo foi o caranguejo porcelanídeo Pachycheles monilifer coletado em dois substratos biológicos diferentes, no briozoário Schizoporella errata no píer do Itaguá e no poliqueto Phragmatopoma caudata na praia Grande, ambas as paias localizadas em Ubatuba, litoral norte de SP. Somente os embriões em estágio inicial de desenvolvimento foram utilizados para os cálculos de fecundidade e investimento reprodutivo (RO). Os embriões foram contados e medidos sob esteromicroscópio. Para obtenção do RO foram utilizados os pesos secos das fêmeas ovígeras e das massas de embriões, previamente secos em estufa. Além dos aspectos reprodutivos, análises de distância genética também foram realizadas pelo sequenciamento de genes mitocôndrias (16S e COI) de exemplares de P. monilifer. A estimativa da porcentagem de variação genética intra e interespecífica, a possibilidade de fluxo gênico entre indivíduos de diferentes praias do estado de São Paulo foram verificadas. A partir desses dados confirmou-se a validade da espécie, assim como o fluxo gênico contínuo entre indivíduos dessas duas praias. A baixa divergência genética permite concluir que as diferenças reprodutivas encontradas são, portanto um reflexo das condições proporcionadas pelo ambiente. Os animais simbiontes do briozoário, assim como as fêmeas ovígeras, são maiores que os associados ao poliqueta e também possuem maior fecundidade e investimento reprodutivo, porém não foram encontradas diferenças em relação ao tamanho dos embriões. No substrato do briozoário o estresse reprodutivo parece ser menor que no substrato do poliqueto, já que aquele substrato proporciona um ambiente fisicamente mais estável para os organismos simbiontes. No substrato do poliqueto, além do alto hidrodinamismo local, o espaço disponível na colônia parece ser mais restrito e pode limitar o tamanho de seus habitantes. Os animais simbiontes do briozoário parecem não serem influenciados por fatores externos à colônia, entretanto o mesmo não foi observado nos simbiontes do poliqueto. Tais diferenças reprodutivas refletem o tipo de substrato ocupado, evidenciando a plasticidade fenotípica da espécie para uma melhor adaptação local. / The crustaceans are the most diverse of the marine invertebrates and many of them tend to associate with other organisms where they can find shelter, food supply and a safe place to reproduce. Reproductive traits as fecundity, egg size and reproductive output (RO) are the most important aspects to understand the species life history. This study aimed to investigate the reproductive traits in relation to the substrate that the organisms live. The studied species used as model was the porcellanid crab Pachycheles monilifer that was collected in two different substrates, one of them is the bryozoan Schizoporella errata at the Itaguá beach and the other is the polychaete Phragmatopoma caudata at Grande beach, both are located in Ubatuba, northern coast of São Paulo. Only the initial stage of eggs was used to estimate the crab fecundity and RO. The eggs were counted and measured in a stereomicroscope. To obtain the RO the female and the egg mass dry weight, which were previously dried in an oven, were used. Besides the reproductive aspects, the genetic distance between the organisms was valued with partial sequences of the mitochondrial genes 16S and COI. The estimate of the intra and interspecific genetic variation and the possibility of gene flow between the individuals from the beaches in SP were analyzed too. Therefore, with all these analyses it was possible to confirm that the species is valid and that there is gene flow among the populations. The low genetic divergence allowed us to conclude that the different reproductive traits found among the populations were due to the different substrates that the organisms inhabit. The bryozoan symbionts are larger than the polychaete symbionts as well as the females fecundity and the RO, but there is no difference in egg size. In the bryozoan substrate it seems like the physical stress is smaller than in polychaete and it promotes a more stable habitat for the crabs reproduce. In the polychaete substrate, beyond the high hydrodynamic location, the available space in the colony appears to be narrower, which could limit the size of its inhabitants. The bryozoan symbionts do not seem to be influenced by the external factors of the colony, though the same was not observed in the polychaete colony. Such differences in reproduction reflect the kind of substrate inhabited, highlighting the phenotypic plasticity of the species to a local better adaptation.

Master of Science / Department of Clinical Sciences / James W. Carpenter / Current in vitro maturation (IVM) systems for domestic dog oocytes are inefficient, largely due to the species' unique reproductive physiology. The size of donor follicle influences developmental competence of dog ovarian oocytes. Specifically, oocytes from follicles > 2 mm in diameter complete in vitro nuclear maturation at a higher rate than those from smaller follicles. The objective was to determine the influences of follicular size, maturation time, and meiotic status on oocyte metabolism. We hypothesized that metabolic patterns differed between oocytes from small versus large follicles. Oocytes (n = 531) from adult ovaries were collected and grouped based on follicular size (small, < 1 mm, n = 252; medium, 1 to 2 mm, n = 231; and large, > 2 mm, n = 48). Oocytes were cultured for 0, 24, or 48 hours at 38.5°C in 5% CO[subscript]2 in 80 [Mu]L of TCM 199 + 25[Mu]M [Beta]- mercaptoethanol + 10 ng/ml epidermal growth factor + 0.25 mM pyruvate + 2.0 mM glutamine + 0.1% polyvinyl alcohol + 0.03 mg/ml streptomycin + 0.03 mg/ml penicillin G sodium (IVM medium), assessed for metabolism and evaluated for nuclear status. For metabolic assessments, oocytes were incubated for 3 h in 3 [Mu]l of IVM medium containing (1) 0.005 mM [0.064 [Mu]Ci/[Mu]l] D-53H-glucose (glycolysis) + 1 mM D-614C [0.053 [Mu]Ci/[Mu]l] glucose (glucose oxidation) or (2) 0.001 mM [0.041 [Mu]Ci/[Mu]l] L-G-3H-glutamine + 1 mM [0.027 [Mu]Ci/[Mu}l] 1-14C pyruvate, placed on the lid of a centrifuge tube containing 25 mM NaHCO3 and trapped radioactivity was measured using a [Beta]-counter. Only oocytes at an appropriate meiotic stage for each culture period (n = 380) were included in data analysis (e.g., germinal vesicle stage at 24 and 48 h culture were excluded). Differences in metabolism among groups were analyzed by ANOVA (main effects being follicular class, culture interval, and meiotic status). Oocytes recovered from large follicles metabolized significantly more pyruvate, glutamine, and glucose (via glycolysis) than those from small ones (p < 0.05). Across meiotic stages and follicular sizes, glycolytic rate was lowest in oocytes cultured for 24 hours (p < 0.05) compared to 0 or 48 hours. Metaphase II oocytes had a significantly higher glycolytic rate than those at other meiotic stages (p < 0.05). At culture onset (0 h), oocytes from small follicles predominately used pyruvate (p < 0.05), while oocytes from larger follicles (p < 0.05) predominately metabolized glucose. The present data suggests that dog oocytes preferentially use glucose as an energy substrate and that increasing glycolytic rate correlates with meiotic maturation. In addition, oocytes collected from large follicles exhibit increased metabolic capabilities that may be responsible for their increased developmental competence during IVM.

Electrodeposition method is used to deposit diamond-like carbon (DLC) films on copper substrates via anodic oxidation at low temperature. These films are characterized using Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Homogeneity of these films is studied using Raman spectroscopy and scanning electron microscopy. Scotch tape peel tests indicate adherent film on copper substrate. Carbon phase transformation is studied using thermal annealing experiments in conjunction with Raman spectroscopy and scanning electron microscopy. A cathodic electrochemical method is also studied to deposit diamond-like carbon films on copper substrates. However, films deposited by the cathodic route have poor adhesion and quality compared to anodically deposited films. It is also possible to grow diamond phase on copper substrates using acetylene in liquid ammonia via electrodeposition route. An electrochemical method is proposed for boron doping into DLC films.

The express purpose for doing this project was to develop methods for the continuous culture of E. coli and P. aeruginosa as a mixed population, and to apply these methods in studying the effects of pH and substrate upon the growth of these two organisms in mixed continuous culture.

Cette thèse est une étude sur la caractérisation, la modélisation et l’optimisation des effets substrat dans les circuits intégrés, dédies à des applications WLAN.L’objectif de ces travaux de recherche est de développer une nouvelle méthodologie d’extraction qui prenne en compte tous les parasites ; à savoir les modèles RLCK distribués, les effets électromagnétiques, ainsi que le couplage substrat.Les effets substrat ont été optimisés grâce au développement de nouvelles structures d’isolation utilisant des tranches profondes d’isolation (DTI).La prédictibilité des simulations circuits a été améliorée grace à l’introduction d’une nouvelle méthodologie d’extraction, basée sur une approche quasi-statique prenant en compte avec précision la description exacte et complète du procédé BiCMOS ainsi que les pertes dans le substrat, aussi bien diélectriques que résistives.La validité de cette méthodologie a été évaluée en comparant les résultats de simulation avec les mesures sur silicium. La bonne corrélation des résultats démontre la pertinence de cette nouvelle méthodologie. Cette méthode permet de plus, de réduire le « time to maket » grâce à l’optimisation des temps de simulations. / This thesis is about characterization, modelling and optimization of substrate effects in integrated circuits, dedicated to WLAN applications.The objective of this thesis is to develop a new extraction methodology that takes into account all parasites; distributed RLCK models, electromagnetic effects, as well as substrate coupling.Substrate effects have been optimized through the development of a new insulation strategies using deep isolation isolation (DTIs).The circuit predictability has been improved thanks to the development of a new extraction methodology, based on a quasi-static approach taking into account the complete description of the BiCMOS process as well as the substrate loss, both capacitive and resistive effects.The validation of this methodology was evaluated by comparing simulation results with silicon measurements. The good correlation of the obtained results demonstrates the accuracy of this new methodology. This method also makes it possible to reduce the time to market thanks to the optimization of the simulation times.

Lors d’une blessure, les cellules migrent et prolifèrent collectivement pour rétablir la continuité de l’épithélium. En migrant, les cellules exercent des forces entre elles ainsi que sur le substrat et de nombreuses études suggèrent un couplage mécanique entre la migration et la prolifération. Récemment découvert, le cofacteur de transcription Yap (Yes-associated protein) est régulé par des signaux mécaniques. L’activation de YAP se traduit par sa rétention nucléaire et augmente la prolifération cellulaire. D’un point de vue mécanique, l’engagement des intégrines dans les adhésions focales, l’aire d’étalement des cellules et la contractilité de l’actomyosine activent YAP. Au contraire, l’engagement des cadhérines dans les jonctions intercellulaires inhibent Yap. A ce jour, les contributions respectives des contacts cellulaires et de l’actomyosine pour la régulation de Yap de de la prolifération restent inexplorées.Au cours de cette thèse, nous nous sommes intéressés au rôle des adhésions au substrat, des jonctions cellule-cellule, du cytosquelette d’actomyosine et de la tension mécanique inter- et intracellulaire sur l’activation de YAP et sur la prolifération cellulaire pendant la cicatrisation épithéliale.D’abord, nous avons étudié le rôle de l’étalement cellulaire et des forces transmises par les contacts cellule-substrat sur la régulation de la localisation de Yap. En confinement sur des motifs adhésifs micro-fabriqués, les kératinocytes humains (HaCaT) adoptent un mouvement collectif oscillatoire. En combinant la vidéomicroscopie, la microscopie à force de traction (TFM) et l’analyse quantitative d’images, nous avons d’abord montré que la migration des cellules est alternativement divergente et convergente ce qui régule l’étalement des cellules. Nous avons ensuite montré que l’étalement d’une cellule est corrélé aux forces de traction sur le substrat et à la relocalisation nucléaire de Yap. Bien qu’ils soient encore préliminaires, ces résultats suggèrent que Yap est régulé par les forces transmises au contacts cellule-substrat pendant la migration épithéliale.Ensuite, nous nous sommes intéressés à la régulation de Yap et de la prolifération cellulaire pendant la migration épitheliale en absence de contacts cellule-substrat. Pour cela, nous avons forcé la migration de monocouches de cellules HaCaT sur des bandes adhérentes séparées de bandes cytorépulsives. Lorsqu’elles migrent sur les bandes adhérentes, les cellules HaCaT étendent une couche de cellules suspendues au-dessus des bandes cytorépulsives. Les cellules suspendues sont cohésives entre elles mais n’interagissent pas avec le substrat. Dans le feuillet de cellules suspendues, les fibres de stress d’actine se réorganisent à l’échelle du tissu grâce au renforcement des contacts cellule-cellule et la contractilité est augmentée. Ce modèle est le premier qui permet de découpler la contractilité de l’actomyosine et les adhésions cellule-substrat pendant la migration épithéliale. Malgré l’augmentation des contraintes d’étirement, l’absence de contacts cellule-substrat empêche la localisation nucléaire de YAP et inhibe la prolifération des cellules suspendues. En conclusion, l’engagement de contacts cellule-substrat sont nécessaires à la localisation nucléaire de Yap et à l’augmentation de la prolifération pendant la cicatrisation épithéliale in vitro.Ces travaux démontrent que les forces de traction sur le substrat sont associées à la localisation nucléaire de Yap et à l’augmentation de la prolifération pendant la migration épithéliale in vitro / After a wound, cells both migrate and proliferate collectively to restore epithelial continuity and to heal the wound. While migrating, cells exert forces on the substrate and pull on each other. Several previous studies suggest a mechanical coupling between collective cell migration and proliferation. Recently discovered, the transcription co-factor Yap (Yes-associated protein) is regulated by mechanical signal. Yap activation induces its nuclear retention and cell cycle progression. Integrin engagement on cell-substrate contacts, cell spreading and actin contractility are related to Yap activation. In turn, cadherin engagement and forces in cell-cell contacts induces Yap nuclear exclusion and reduce cell proliferation. Integrins and cadherins anchor actomyosin cytoskeleton and to date, and the respective contributions of cell-substrate adhesions, cell-cell junctions and actin cytoskeleton on regulation Yap and cell proliferation remain unexplored.In this thesis, we interested in the role of substrate adhesions, cell-cell junctions, actomyosin cytoskeleton and cell mechanical loading on Yap activation and cell proliferation during epithelial wound healing.First, we aim to understand the role of cell spreading and mechanical loading of cell-substrate contacts on the regulation of Yap localisation. Confined on microfabricated adhesive patterns, human keratinocytes HaCaT adopt an oscillatory collective motion. Combining videomicroscopy, traction force microscopy (TFM) and quantitative image analysis, we show that collective cell movements are alternatively divergent and convergent which regulate local cell spreading. Then, we show that cell spreading correlate with traction forces on the substrate and nuclear localisation of Yap. While it remains preliminary, our data show that forces at cell-substrate contacts and cell spreading induce nuclear localisation of Yap during collective cell movements.In the second part of the thesis, we interested on Yap localisation and proliferation during epithelial migration in absence of cell-substrate contacts. To do so, we forced migration of monolayer of HaCaT keratinocytes on micropattern comprising alternatively adherent and cytorepulsive stripes. While migrating on adherent line, cells extend a multicellular layer over the non-adherent areas. Suspended cells are cohesive with each other but do not engage cell-substrate adhesion. In the suspended cell layer, actin stress fibres reorganise at the tissue level thanks to reinforcement of cell-cell contacts and contractility is increased. This model is the first one that allow to decouple actomyosin contractility and cell-substrate contact during epithelial migration. Despite increased stretching stress, absence of cell-substrate contacts induces Yap cytoplasmic localisation and inhibits cell proliferation. To conclude, cell-substrate contact engagement is necessary to induce Yap nuclear localisation and increase cell proliferation during epithelial wound healing in vitro.This work demonstrates that traction forces through cell-substrate contacts are associated to nuclear localisation of Yap and to increased cell proliferation during epithelial wound healing in vitro