Thèses sur le sujet « Gpa2 »

Nous avons caractérisé cinq protéines bovines qui sont potentiellement impliquées dans la reproduction.Un travail de clonage a été initié qui permettra à terme de purifier les GPA2 et GPB5 recombinantes puis naturelles pour étudier leurs structures. GPA2 et GPB5 sont considérés comme les ancêtres moléculaires des sous-unités α et β des hormones glycoprotéiques. Nous avons montré la relative fragilité thermique de la structure quaternaire de la FSH bovine par rapport aux FSH ovine et humaine et nous avons étudié les propriétés enzymatiques de la PDI (Protein Disulfide Isomerase) en préalable à l’étude de l’activité PDI de GPA2/GPB5. Nous avons aussi purifié la phosphatidyl-ethanolamine-binding protein (PEBP) et l’ubiquitine testiculaires par chromatographie hydrophobe à très haute concentration de sulfate d’ammonium. A partir de la PEBP purifiée, on a produit des anticorps spécifiques chez le lapin qui nous ont permis d’être les premiers à développer un dosage ELISA fiable pour cette protéine
We characterized five bovine proteins that are potentially involved in reproduction. We started with the cloning of gpa2 and gpb5 cDNAs in order to eventually purify recombinant and natural GPA2 and GPB5 to study their possible quaternary structure. GPA2 and GPB5 are the evolutionary ancestors of Glycoprotein hormones α and β subunits respectively. Meanwhile, we have shown the relative quaternary structure fragility of bovine FSH compared to human and sheep FSH. We also studied the effect of endocrine disruptors on PDI (Protein Disulfide Isomerase) before addressing GPA2/GPB5 PDI activity of GPA2/GPB5 once purified.We succeeded to purify the phosphatidyl-ethanolamine-binding protein (PEBP) and ubiquitin from bovine testis by hydrophobic interaction chromatography at very high ammonium sulfate concentration and we produced specific antibodies (anti-PEBP) in rabbits that allowed us to be the first to develop a reliable Elisa assay for this protein

In the yeast Saccharomyces cerevisiae, the Ras proteins are part of the cAMP/PKA signalling pathway, which plays a fundamental role in the control of many cellular processes including cells proliferation, stress resistance, metabolism, and growth. They belong to the super-family of the small GTPases that act as molecular switches by cycling between an inactive GDP-bound form and an active GTP-bound form. This process is controlled by two classes of regulatory proteins: the GEFs promote the activation of Ras by catalyzing the GDP-GTP exchange, whereas the GAPs turn off the Ras proteins by stimulating the hydrolysis of GTP to GDP. In the first section of this thesis, we investigated the localization of active Ras proteins in wild type cells and in mutants in several components of the cAMP/PKA pathway to understand how the proteins involved in this pathway influence the localization of active Ras. To this aim we used a probe in which the eGFP (enhanced green fluorescent protein) is fused to a trimeric Ras binding domain (RBD3) of the human Ras effector, c-Raf1. This RBD directly binds to the active Ras with a much higher affinity than the inactive Ras. We also investigated the influence of PKA activity on active Ras localization analyzing different mutants with either high or low/absent PKA activity. The cells of the different strains expressing the eGFP-RBD3 probe growing on glucose medium were observed under the microscope. In wild type cells, Ras-GTP was mainly localized at the plasma membrane and surprisingly in the nucleus. In cyr1∆ and gpr1∆ cells, the probe showed a similar localization as in wild type cells. In gpa2∆, hxk2∆ and hxk1∆hxk2∆ cells, the fluorescence accumulated in internal membranes and mitochondria. However, in the hxk1∆hxk2∆ cells transformed with the centromeric plasmid YCpHXK2 expressing Hxk2, the eGFP-RBD3 probe was mainly localized at the plasma membrane and in the nucleus. These results suggest that Gpa2 and Hxk2 play a role in the localization of active Ras. We also observed that the localization of active Ras is dependent on PKA activity. Indeed, in the bcy1∆ mutant, showing high PKA activity, there was a clear relocalization of active Ras to the cytoplasm and to the nucleus, while no active Ras was localized at the plasma membrane anymore. In a strain with either reduced PKA activity, the tpk1w1 tpk2∆ tpk3∆ strain or absent PKA activity, the tpk1∆ tpk2∆ tpk3∆ yak1∆ strain, active Ras was mainly localized at the plasma membrane. In the second section of this thesis, we investigated the role played by active Ras in the nucleus. To this aim, a fusion was made between the Ras2 protein and the Nuclear Export Signal (NES) from the HIV virus (HIV virus Rev protein NES) (Henderson et al., 2000), generating the NES-RAS2 strain. Our results showed that the exclusion of Ras2 protein from the nucleus did not cause a growth defect neither on fermentable nor non fermentable carbon sources and did not influence the PKA related phenotypes analyzed in our work. Cells expressing the fusion protein were only defective for the invasive growth, suggesting that nuclear active Ras2 is involved in this cellular process. These results were confirmed using also the Tlys86 strain, that is commonly used to test this phenotype. We also demonstrated that the nuclear localization of Cdc25, the main GEF of Ras proteins, is required for invasive growth and that PKA activity controls invasive growth influencing the localization of active Ras. Data in literature (Cazzaniga et al., 2008; Pescini et al., 2012) show the presence in silico of cAMP levels oscillations. In the last section of this thesis, we tested two different FRET sensors, previously used in mammalian cells, to monitor the cAMP levels (CFP-Epac1-YFP probe) and PKA activity in single cells in vivo (AKAR3 probe). We inserted the sequences coding for the CFP-Epac1-YFP sensor and for the AKAR3 sensor in a multicopy yeast expression vector and the sensors were expressed under the control of the TPI promoter in several yeast strains. We used a two-photon confocal microscope system to measure the FRET efficiency. Our preliminary results showed that in a wild type strain expressing either the Epac sensor or the AKAR3 sensor there was respectively an increase of cAMP level and PKA activity in a single yeast cell after glucose addition to glucose-starved cells.

Afin de lutter contre le nematode à kyste de la pomme de terre, Globodera pallida, l’utilisation de variétés résistantes est maintenant préconisée. Cependant la plupart des gènes de résistances connus, comme le gène majeur Gpa2 ne sont efficaces que vis-à-vis d’un nombre réduit de populations. De plus Gpa2 nécessite la présence d’un co-facteur, RanGAP2, pour reconnaître la protéine d’avirulence du nématode codée par le gène Gp-Rbp-1 et déclencher alors les mécanismes de défenses de la plante. L’objectif de cette étude est de caractériser le spectre d’e efficacité de Gpa2 vis-à-vis de populations de G. Pallida originaires d’Europe et d’Amérique du Sud (bassin d’origine du nématode) et de décrire la variabilité moléculaire et fonctionnelle de Gp-Rbp-1 et chez Gp-Rbp-1 qui pourrait affecter l’interaction ave Gpa2 et du polymorphisme chez RanGAP2 qui pourrait être utilisé pour élargir le spectre d’action du gène Gpa2. Nous avons montré que la sensibilité d’un cultivar de pomme de terre exprimant Gpa2 à une population de G. Pallida ne pouvait être expliquée exclusivement par la fréquence de variants avirulents de Gp-Rbp-1 dans cette population de nématodes. De plus parmi les huit sites de Gp-Rbp-1 détectés sous slection positive, la seule variation d’acide mainé en position 187 (proline/sérine) s’est avérée suffisante pour expliquer la reconnaissance de GP-RBP-1 par GPA2. Malgré de nombreux sites détectés sous sélection purifiante, RanGAP2 présente deux sites polymorphes (acides aminés 106 et 237) et une insertion/délétion d’intérêt. La variabilité au niveau de ces sites ne permet pas la reconnaissance des variants virulents (non reconnus ) de GP-RBP-1 par GPA2 mais semble néanmoins affecter l’intensité de la réaction d’hypersensibilité qui se produits lors de lla reconnaissance des variants avirulents de GP-RBP-1 par GPA2
In order to control the potato cyst nematode. Globodera pallida, using resistant varieties is now advocated. Nevertheless, most of the resistance genes, including ther major gene Gpa2 are efficient only against a lim ited number of nematode populations. Moreover Gpa2 needs the presence of a co-factor – RanGAP2 – to recognize the nematode avirulence protein coded by the Gp-RBP-1 gene and to trigger the plant defence mechanisms. The present work aims to characterize the efficiency spectrum of Gpa2. Our goals were to identify the Gp-Rbp-1 polymorphisms affecting the outcome of the interaction with Gpa2 and the polymorphisms in RanGAP2 that can be used to expand the range of G. Pallida populations controlled by Gpa2. We have shown tha susceptibility of a potato cultivar expressing Gpa2 to a G. Pallida population. Furthermore, among the eight sites of Gp-Rbp-1 found under positive selection, the sole variation at amino acid position 187 (proline/serine) remained sufficienet to explain the recognition of GP-RBP 1 by GPA2. Despite numerous sites found to have evolved under purifying selection, RanGAP2 have two polymorphic sites (amino acids 106 and 237) and one insertion/deletion of interest. Variability observed at these sites do not enable the recognition of virulent variants (non-recognized) of GP-RBP-1 by GPA2 but seems to affect intensity of the hypersensitive response triggered by the recognition of avirulent variants of Gp Rbp-1 GPA2

Le but de cette recherche etait essentiellement de determiner les facteurs qui influent sur le choix d'une methode et d'un outil de pilotage de la production, et de proposer, en coherence avec cette etude, un referentiel synthetique montrant les liens privilegies entre les differentes situations industrielles et l'utilisation de telle ou telle approche de pilotage. Ce double objectif devait permettre d'apporter une contribution a la connaissance du pilotage de la production tant d'un point de vue theorique, en precisant notamment l'adequation des methodes et outils de pilotage aux differentes problematiques de production, que sur le plan pratique de l'aide a la decision, en facilitant le choix de l'approche de pilotage la plus adaptee a un systeme de production donne. La methode d'investigation retenue s'est basee sur trois etapes. Une phase theorique a permis d'etablir une typologie des systemes de production qui a servi de cadre pour developper un modele d'aide au choix des methodes et outils de pilotage de la production. Ce modele croise entre eux trois criteres principaux : le mode de reponse au marche, la nature du flux et le profil du flux. Une phase d'etude empirique a eu pour objet d'etudier sur le terrain la realite des pratiques de choix, en vue d'une prise en compte de la complexite du reel. Enfin, une troisieme phase a permis de boucler la recherche en integrant la complexite du reel dans le modele initial. Le referentiel a ete amenage pour integrer les criteres manageriaux et traiter la problematique des systemes mixtes.

Gp12 est une protéine qui se fixe symétriquement au centre de chacun des 60 hexamères de la capside icosaédrique du bactériophage SPP1. La protéine produite dans un système d’expression hétérologue se lie à la capside de particules virales dont le gène codant gp12 a été inactivé. Cette interaction a lieu spécifiquement avec des capsides qui ont subi le processus d’expansion et encapsulé l'ADN viral.L'analyse de la séquence de gp12 montre la présence d'un motif (GXY)n retrouvé dans des protéines de type collagène. Nous avons démontré que gp12 est un trimère allongé en solution. Ce trimère s'avère sensible à la collagénase VII qui coupe la protéine gp12 dans un site spécifique du motif (GXY)8. Le profil de dichroïsme circulaire de gp12 porte aussi la signature d'une protéine de type collagène. La fixation de gp12 sur la capside virale conduit à une augmentation de 20°C de sa stabilité thermique. Gp12 peut être dénaturée-dissociée et puis renaturée-reassociée sous l'effet de la température. Le trimer de gp12 et sa forme dénaturée se fixent à la capside de SPP1 mais avec des profils d’interaction différents. Ces propriétés permettent d’utiliser gp12 comme un ligand réversible de la capside phagique en fonction de la température. Gp12 a une organisation modulaire avec un motif collagène qui sépare les modules amino et carboxyl-terminaux. Des protéines avec une organisation similaire sont codées par des gènes adjacents à celui codant pour la protéine majoritaire de la capside dans des prophages de Bacilli, suggérant une fonction similaire à gp12. Leurs modules ont une taille variable. Une recherche de protéines procaryotes et virales avec des segments collagène a montré qu’elles sont abondantes parmi les bactéries et les virus. Le motif est rare parmi les archées et leurs virus. Ces résultats montrent l’importance des protéines avec des séquences de type collagène dans le monde non-eucaryote et du développement de leur étude biochimique et fonctionnelle
Gp12 is a protein found distributed symmetrically at the surface of the icosahedral capsid from bacteriophage SPP1. Recombinant gp12 binds to phage particles whose gene coding for gp12 was disrupted. This interaction occurs specifically with capsids that undergone expansion and packaged DNA.The gp12 protein sequence is marked by the presence of a stretch of 8 repeats of a GXY motif, which is the sequence signature of collagen. Our results showed that gp12 is an elongated trimer in solution. The trimer is sensitive to collagenase VII that cuts the gp12 protein inside the collagen motif. Its circular dichroism profile has also the signature of a collagen-like protein. Binding of gp12 to SPP1 capsids increases its thermal stability by 20°C. Gp12 is denatured and dissociated reversibly by temperature shift. The gp12 trimer and its denatured form bind to SPP1 capsids but with a different interaction behavior. These properties allow to use gp12 as thermo-switchable SPP1 capsid binder. Gp12 has a modular organization with a central collagen motif that connects the amino and carboxyl termini. Proteins with a similar organization that are encoded by genes adjacent to the gene coding for the major capsid protein were identified in prophages of Bacilli, suggesting a function similar to gp12. Their modules have a variable length.A pangenome-wide search for collagen-like proteins in prokaryotes and viruses shows that they are abundant among bacteria and viruses. In contrast, this motif is rare is archaea and their viruses. Our analysis highlights the importance of collagen-like proteins in the non-eukaryotic world and supports the interest to develop their biochemical and structural study

L'obésité est aujourd’hui considérée comme une maladie inflammatoire chronique dite de « bas grade » principalement caractérisée par une augmentation de l’inflammation du tissu adipeux. Les adipocytes et les macrophages sont connus pour jouer un rôle clé dans l’établissement, la progression et le maintien de l'inflammation. Dans mon projet de thèse, nous nous sommes particulièrement intéressés aux mécanismes transcriptionnels impliqués dans l'inflammation chronique en décodant l'action du corégulateur transcriptionnel GPS2 (G protein pathway suppressor 2) dans les adipocytes et les macrophages du tissu adipeux. Dans un premiers temps, nous avons étudié la régulation et les actions de GPS2 (et ses partenaires SMRT et NCOR) dans le tissu adipeux humains de sujets obèses par rapport à des sujets minces. Dans cette première étude, nous avons identifié un mécanisme épigénomique qui participe à la régulation de la transcription des gènes inflammatoires dans les adipocytes lors de l’obésité. Nous avons démontré que la dérégulation de GPS2 contribuait à l'inflammation du tissu adipeux en permettant à la dérépression de certains gènes inflammatoires dont l’interleukine 6. Dans la deuxième étude, nous avons caractérisé les conséquences de l’invalidation de GPS2 dans le phénotype inflammatoire des macrophages ainsi que les conséquences in vivo sur la progression de l’insulino-résistance. Pour ceci, nous avons généré un modèle de souris où GPS2 a été spécifiquement invalidé dans les macrophages (GPS2-MacKO). De manière intéressante, les souris GPS2-MacKO, présentent une expression accrue des gènes impliqués dans la voie de signalisation des TLR et des chimiokines dans les macrophages isolés. Par conséquent, une augmentation significative de l'infiltration des macrophages dans le tissu adipeux est observée dans un contexte d’obésité induisant une altération de l’homéostasie glucidique. Par nos approches génomiques, transcriptomiques et épigénomiques, nous avons pu révéler les voies de signalisations spécifiquement contrôlées par GPS2. Ces travaux démontrent également l’importance des régulations épigénomiques dans l'inflammation métabolique du tissu adipeux durant l'obésité
Obesity is now considered a chronic low-grade inflammatory disease with increased levels of inflammatory mediators both in circulation and adipose tissue. Among adipose tissue cell types, adipocytes and macrophages are known to play key roles in the progression of inflammation by establishing and maintaining it. In this PhD project, we particularly focus on the transcriptional mechanisms behind the chronic low-grade inflammation by deciphering the action of GPS2 in adipocytes and adipose tissue macrophages. We initially studied the gene regulation and the actions of GPS2 and its partners in adipose tissue and adipocytes of human obese subjects compared to lean subjects. In this first study we identified a novel regulatory pathway that participates in the transcriptional control of inflammation associated with obesity, both in adipose tissue and adipocytes. We have shown that GPS2 and SMRT were differentially expressed and regulated in obese adipocytes. In addition, this dysregulation contributes to inflammation of the adipose tissue by allowing the derepression of specific inflammatory genes. In a second study, in order to go further in the characterisation of the in vivo function of GPS2, we generated a mouse model were GPS2 was specifically invalidated in macrophages. Models of diet-induced obesity were applied in these experiments. Interestingly, GPS2-MacKO mice showed an increased expression of inflammatory genes both in adipose tissue and isolated ATMs (F4/80+ cells) associated with a significant increase of macrophages infiltration in the adipose tissue. Finally, we observed that GPS2-MacKO mice had impaired glucose metabolism as they presented high glucose intolerance as well as an important insulin resistance

L'outil présenté utilise les principes de la méthode GRAI en particulier une modélisation hiérarchique et fonctionnelle du système étudié. Il s'agit d'un système expert capable d'élaborer un bilan d'analyse à partir d'une représentation du système de gestion de la production étudié, qui est entrée à la fois graphiquement et sous la forme d'objets stockés dans une base de données.

Alanine has long been recognized as an important substrate for hepatic gluconeogenesis through the glucose-alanine (Cahill) cycle which plays an important role in the maintenance of euglycemia during times of caloric deficiency. The Cahill cycle involves the transamination of pyruvate by the amino group of glutamate, producing α-ketoglutarate and alanine. Alanine formed in skeletal muscle during exercise can be sent to the liver where it is used to produce glucose and safely remove the NH₃₊ as urea. This process is catalyzed by the glutamic-pyruvic transaminase (GPT) enzyme, of which two distinct isoforms exist: cytosolic GPT1 and mitochondrial GPT2. However, the precise role of these different enzymes in alanine metabolism remains to be fully elucidated and is an ongoing subject of debate. Likewise, the potential efficacy of exogenous alanine administration as a strategy to improve skeletal muscle glycogen recovery following exercise has not been examined. The following studies were conducted to: 1) evaluate the metabolic effects of L-alanine administration following a bout of exhaustive exercise and 2) determine the role hepatic GPT2 plays in gluconeogenesis from alanine during exercise.

Administration of L-alanine to C57BL/6 mice kept fasted after an exhaustive bout of exercise did not significantly alter glycogen content in the gastrocnemius during 1 hour of recovery; despite the observation that blood glucose concentrations were elevated at this time compared to mice treated with sterile saline. In addition, treatment with L-alanine resulted in significantly increased blood lactate concentrations at 30 and 60 minutes of recovery.

Liver specific GPT2–/– mice are overtly normal and survive to adulthood with normal exercise tolerance. Gene expression analysis by qPCR reveals LS-GPT2–/– mice have higher levels of GPT1 mRNA, which may act to compensate for the loss of GPT2. Indeed, liver specific deletion of GPT2 and the mitochondrial pyruvate carrier 2 (MPC2) resulted in reduced exercise time to exhaustion. Impaired gluconeogenesis was also observed in double knockout mice following 1 hour of recovery from exercise in the fasted state.

These studies demonstrate that immediately following exercise alanine is not a limiting substrate for skeletal muscle glycogen replenishment or hepatic gluconeogenesis. In addition, we show that loss of GPT2 alone is not sufficient to reduce exercise performance or gluconeogenesis due to compensatory changes in gene expression.

The purpose of this study was to determine the correlation between a students Grade Point Average (GPA) and a student's proximity to campus. There were also two other independent variables studied, the students gender and the number of roommates the student has. The results showed that there is no correlation between GPA and proximity to campus or GPA and number of roommates. The only correlation found, which was slight, was between GPA and gender.

Bovine vaccinia (BV) is a zoonosis caused by Vaccinia virus (VACV), which affects dairy cattle and milkers, and causing economical, animal and human health impacts. By the clinical presentation of the disease, it seems that BV is a localized disease, with lesions restricted to the skin of affected individuals. But there are no studies about the pathogenesis of the disease in cows to access if there is a systemic spread of the virus and if there are different ways of VACV shedding. This work had the objective to study if occurs viremia and VACV shedding in the feces of VACV experimentally infected cows. To this end, ten crossbred lactating cows, serologically negative for VACV, were used. Three teats of each cow were scarified using sandpaper, followed by inoculation of 106 UFP/50µL of Guarani P2 (GP2V) strain of VACV. All animals were monitored daily and blood and feces samples were collected for 67 days post infection (d.p.i.). After this period, all animals that were previously infected were divided in two treatment groups: re-infection or immunodeppression. All animals developed lesions compatible with VB (papules, vesicles and ulcers), and even after the resolution of the lesions, viral DNA was detected in the blood and lymphoid tissues, as well as an intermittent and extended detection of VACV DNA in the feces, until the last day of collection (67 day post infection), suggesting that VACV infection is chronic. The detection of VACV viable particles in the feces suggests that this is a possible route of viral shedding in the environment, which may favor VACV transmission within and among properties. VACV infections in cattle are associated with infection of epithelial cells and goblet cells in the intestine, and macrophages and lymphocytes in lymphoid tissues. In the animals experimentally infected and then immunodepression, VACV DNAnemia and DNA detection in feces were observed even before the immunodepressive treatment. There was a tendency to an increase in DNA detection in the blood and feces after the treatment, suggesting that there is some mechanism of VACV persistent infection in cattle and that this is influenced by the immune system. The group of animals that were reinfected by VACV, presented lesions in the teats once more, and VACV DNAnemia was observed. This study showed new evidence that VACV infection in cattle is systemic, has a chronic course and that there is viral shedding on the feces.
A vaccínia bovina (VB) é uma zoonose causada pelo Vaccinia virus (VACV), que afeta vacas leiteiras e seus ordenhadores, causando impactos econômicos e na saúde pública e animal. A apresentação clínica da doença é caracterizada pela presença de lesões localizadas na pele dos indivíduos afetados. Em bovinos não existem estudos sobre a patogênese da doença que descrevam a forma de disseminação do vírus, bem como suas vias de excreção. Este trabalho teve por objetivo estudar a ocorrência de viremia e da excreção do VACV nas fezes de vacas experimentalmente infectadas com este vírus. Para tanto, dez vacas mestiças, em lactação, sorologicamente negativas para o VACV foram utilizadas. Três tetos de cada vaca foram escarificados utilizando lixa e inoculadas com 106 UFP/50µL de VACV, amostra Guarani P2. Os animais foram acompanhados e coletadas amostras de sangue e fezes durante um período de 67 dias pós-infecção (d.p.i.), quando foram então divididos em dois grupos de tratamento, sendo um submetido à reinfecção e o outro à imunodepressão. Todos os animais desenvolveram lesões compatíveis com a VB (pápulas, vesículas e úlceras). Mesmo após a resolução das lesões, o DNA viral foi detectado no sangue e em tecidos linfóides e de forma intermitente e prolongada nas fezes dos animais até o último dia de coleta (67º dia pós-infecção), demonstrando que a infecção causada pelo VACV é prolongada. A detecção de partículas virais infecciosas nas fezes sugere que essa via de excreção seja uma forma de disseminação do vírus no ambiente, podendo favorecer a transmissão do VACV dentro e entre propriedades. Infecções do VACV em bovinos estão associadas à infecção de células epiteliais e caliciformes no intestino, e em macrófagos e linfócitos em tecidos linfóides. Os animais infectados e posteriormente imunodeprimidos experimentalmente, voltaram a apresentar DNAnemia e permaneceram eliminando o VACV nas fezes com uma tendência a um aumento nesta excreção, podendo sugerir que exista algum mecanismo de persitência na infecção do VACV em bovinos e que este seja influenciado pelo sistema imunológico. Os animais reinfectados pelo VACV voltaram a apresentar lesões nos tetos e DNAnemia. Este estudo demonstra novas evidências de que a infecção do VACV em bovinos seja sistêmica e prolongada, e que ocorra excreção viral nas fezes.

Das seit 1957 als essentiell klassifizierte Spurenelement Selen vermittelt seine Funktion hauptsächlich durch seinen Einbau in Selenoproteine in Form der 21. proteinogenen Aminosäure Selenocystein. Insgesamt wurden 25 humane Gene für Selenoproteine identifiziert, deren genaue Funktion häufig noch nicht bekannt ist. Selen ist das einzige Mitglied aus der Gruppe der Mikronährstoffe, für das nach wie vor eine antikanzerogene Funktion vor allem in Bezug auf Darmkrebs postuliert wird. Die Grundlage dafür liefert eine Interventionsstudie, bei der 1.312 Probanden für 4,5 Jahre mit 200 μg Selen/Tag supplementiert wurden. Dies resultierte in einer Senkung der Gesamtkrebsmortalität um 50 %. Die Fragen einer optimalen Selenzufuhr, die nicht nur den Bedarf deckt, sondern auch die Entfaltung der antikanzerogenen Wirkung von Selen gewährleistet und die zugrunde liegenden molekularen Mechanismen sind noch ungeklärt. Zudem liegt die Selenzufuhr bei einem Großteil der europäischen Bevölkerung unter den Empfehlungen. Deshalb wurden in der vorliegenden Arbeit vier Wochen alte Mäuse für sechs Wochen marginal defizient (0,086 mg/kg Futter) bzw. selenadäquat (0,15 mg/kg Futter) gefüttert. Dieser geringe Unterschied im Selengehalt resultierte in einer Senkung des Plasmaselenspiegels der selenarmen Tiere auf 13 % und der GPx-Aktivität in der Leber auf 35 %. Zunächst wurde der Einfluss von Selen auf die globale Genexpression im murinen Colon mittels Microarray untersucht. Von den im Colon exprimierten Selenoproteinen reagierte die mRNA von SelW, SelH, GPx1 und SelM im Selenmangel besonders deutlich mit Expressionsverlust. Da diese Selenoproteine nicht nur im Colon, sondern auch in Leukozyten reguliert waren, sind sie auch als humane Biomarker für die in dieser Studie gewählte Schwankung des Selengehalts geeignet. Des Weiteren wurde auf Basis der Microarraydaten eine Signalweganalyse durchgeführt, die der Identifizierung krebsrelevanter Signalwege diente, um mögliche molekularbiologische Erklärungsansätze für die Rolle von Selen im Krebsgeschehen zu finden. Es zeigte sich, dass die mRNA von Schlüsselgenen des Wnt-Signalwegs wie β-Catenin, Gsk3β, Dvl2, Tle2, Lef1 und c-Myc auf Schwankungen des Selengehalts reagiert. Vor allem die Induktion von c-Myc, einem Zielgen des Wnt-Signalwegs, deutet darauf hin, dass dieser im Selenmangel tatsächlich aktiver ist als bei selenadäquater Versorgung. Ein weiterer möglicher Erklärungsansatz für die postulierte präventive Funktion von Selen gegenüber Darmkrebs ist die gastrointestinale Glutathionperoxidase (GPx2), die physiologisch in den proliferierenden Zellen des Kryptengrunds exprimiert wird. Die Regulation dieses Enzyms durch den Wnt-Signalweg, der ebenfalls in proliferierenden Zellen aktiv ist, konnte mittels Reportergenanalyse und endogen auf mRNA- und Proteinebene in Zellkultur gezeigt werden. Die Aktivierung verkürzter Promotorkonstrukte und die Mutation eines potentiellen Bindeelements identifizierten den für die Bindung von TCF und β-Catenin verantwortlichen Bereich. Als Zielgen des Wnt-Signalwegs scheint GPx2 zu den an Proliferationsprozessen beteiligten Genen zu gehören, was unter physiologischen Bedingungen die Aufrechterhaltung des intestinalen Epithels gewährleistet. Bei der Entstehung intestinaler Tumore, die in der Initiationsphase zu über 90 % mit einer konstitutiven Aktivierung des Wnt-Signalwegs einhergeht, wirkt GPx2 möglicherweise prokanzerogen. Die genaue Funktion von GPx2 während der Kanzerogenese bleibt weiter zu untersuchen.
Suboptimal selenium (Se) status has been suggested to be associated with a higher risk of developing various cancers, especially colon cancer. In mammals, Se exerts its functions through selenoproteins into which it is incorporated as selenocysteine. Since the function of many selenoproteins has not been identified the underlying mechanisms of the anti-carcinogenic function of Se remains unclear. Therefore, mice were fed either a marginal Se-deficient diet (0.086 mg Se/kg) or a Se-adequate diet (0.15 mg Se/kg) for six weeks. The plasma Se level was reduced to 13 % in the Se-deficient group while GPx activity in the liver was reduced to 35 %. The influence of Se on the global gene expression pattern was analysed using microarray technology. Among selenoproteins SelW, GPx1, SelH and SelM were consistently lower expressed in animals fed with the Se-deficient diet. As the mRNA of these genes was regulated in leucocytes as well, they are possible new biomarkers for the Se status in human studies. In addition, pathway analysis revealed that the cancer-relevant Wnt pathway was affected by the Se status, indicated by changes in the mRNA expression of key proteins like β-catenin, Gsk3β, Dvl2, Tle2, Lef1 and the Wnt target gene c-Myc. The regulation of these genes by Se points to a slightly increased basal activity level of the Wnt pathway in the Se poor state and may therefore contribute to the higher cancer risk in a marginal Se deficiency. Another possible explanation for anti-carcinogenic effects of Se is the gastrointestinal glutathione peroxidase GPx2, a selenoprotein predominantly expressed in proliferating cells at the crypt grounds of the intestine. The regulation of GPx2 via the Wnt pathway was confirmed by reporter gene experiments and by analysing endogenous GPx2 expression on the mRNA as well as on the protein level in different cell culture systems. Shortened promoter constructs and the mutation of a potential TCF binding element identified the area responsible for β-catenin/TCF binding. GPx2 is the first selenoprotein identified as a target of the Wnt pathway. This finding suggests a function of GPx2 in the maintenance of normal renewal of the intestinal epithelium as well as in cancer development.

La necessite d'amelioration de competitivite oblige les industriels a utiliser des solutions informatiques de type produit (progiciels de gestion de production par exemple). Le choix des produits du marche est de plus en plus difficile (criteres economiques, criteres techniques et criteres fonctionnels). Ce travail de recherche propose des concepts (bases sur les objectifs a atteindre et utilisant les principes des activites grai) coherents avec la methodologie grai, permettant d'une part de specifier une application informatique de gestion de production et d'autre part d'etablir les bases d'un cahier des charges pour choisir un progiciel du marche. La demarche proposee permet des iterations entre les phases de specification et les phases d'etude du marche des progiciels.

La technique EPR (Electron Powder Ribbon) permet l'élaboration des rubans de silicium multi cristallin destinés à la fabrication des cellules solaires en utilisant une ligne de fusion obtenue par déflexion magnétique d'un faisceau électronique. Les forts gradients de température sont la cause principale de l'apparition des contraintes thermiques. Leur élimination nécessite une meilleure connaissance des profils de température. A cette fin, nous avons procédé à une modélisation en 3 dimensions des échanges thermiques ; après localisation et évaluation des contraintes à partir des profils de température obtenus, nous adaptons les paramètres de tir age pour que ces profils soient linéaires. Nous analysons expérimentalement les contraintes résiduelles dans le ruban par photo-élasticimétrie infrarouge assistées par ordinateur (PIRAO). Enfin, nous proposons un système de pilotage du faisceau électronique par ordinateur assurant le dépôt d'énergie le mieux adapté aux conditions thermiques énoncées précédemment
Multicrystalline silicon solar cells can be achieved with the Electron Powder Ribbon process (EPR) which use a magnetic deflection of an electron beam to make a fusion line. The hight temperature gradients are responsible of the thermal strains appearance. Their elimination requires a better knowledge of the temperature profiles. In that aim, we try to make a 3 dimensional model of the thermal exchanges. After localization and evaluation of the strains due to the temperature profiles, we fit the elaboration process parameters in order to make the profiles linear. Experimentally, we evaluate the residual stresses by computer aided infrared photo-elasticimetry (PIRAO). We propose a computer driving of the electron beam, to ensure the best energy deposit in agreement with the thermal conditions mentioned before

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nosso principal objetivo foi caracterizar a família gp82 de proteínas, codificada pela família gênica gp82, que é parte da grande família multigênica gp85/trans-sialidase do T. cruzi. Até o início desse estudo, somente a gp82 de superfície, envolvida na invasão celular das formas metacíclicas da cepa CL e identificada pelo anticorpo monoclonal (MAb) 3F6, havia sido descrita. Na primeira parte, investigamos as bases da avirulência in vivo e in vitro das formas metacíclicas do clone CL-14 do T. cruzi , derivado da cepa CL. Descobrimos que a baixa infectividade desses parasitas está associada com a reduzida expressão da gp82 na superfície, reforçando o papel central da molécula na infecção pelo T. cruzi. Além disso, os dados sugeriram que devido à deficiência da gp82, as formas metacíclicas do clone CL-14, como as da cepa G, uti lizam preferencialmente as glicoproteínas gp35/50 para interagir com a célula hospedeira. Na segunda parte, analisamos a expressão e a localização de moléculas da família gp82 em formas metacíclicas das cepas G e CL do T. cruzi. Para isso, isolamos um novo membro (clone C03) que, em contraste com o clones de cDNA representantes da família gp82 previamente descritos, J18 (cepa G) e R31 (cepa CL), não contém o epítopo do MAb 3F6. Na análise comparativa da seqüência de aminoácidos do clone C03, observamos 59,1% de identidade com o clone J18 e 60,2% de identidade com o clone R31. Além disso, quando alinhamos as seqüências de aminoácidos dos clones C03 e Tc-85 (gp85 das formas tripomastigotas de cultura de tecido), observamos 57,2% de identidade, indicando que esse clone também é parte da família gp85/trans-sialidase. Utilizando os anticorpos policlonais anti-J18 e anti-C03, e o MAb 3F6, mostramos que membros da família gp82 são expressos em formas metacíclicas na superfície e intracelularmente, e que alguns desses membros têm localização diferenciada em parasitas dos grupos T. cruzi I e II. Ao contrário da gp82 reativa com o MAb 3F6, específica das formas metacíclicas, outras moléculas da família foram detectadas também nas formas tripomastigotas de cultura de tecido e amastigotas pelos anticorpos policlonais. Na terceira parte, investigamos o efeito da gp82 em sua forma recombinante (J18), sobre a linhagem de melanoma murino Tm5. Observamos que J18 liga-se a essas células induzindo a despolimerização dos filamentos de actina similar à citocalasina-D, droga indutora de apoptose em células de mamíferos. Em vista disso, fizemos uma análise comparativa das alterações no citoesqueleto de actina e eventos característicos de morte celular por apoptose nas células Tm5 tratadas com J18, e na linhagem de melanócitos melan-a, da qual Tm5 é derivada. Mostramos que J18 tem função indutora de apoptose somente sobre as células do melanoma Tm5. Descrevemos assim uma propriedade de um membro da família gp82, nunca antes descrita para nenhum outro componente molecularmente definido do T. cruzi.
The main goal of this work was to characterize the proteins encoded by the gp82 gene fami ly, which is part of the large T. cruzi gp85/trans-sialidase multigenic family. Previous studies had focused on the surface gp82, which is engaged in the cell invasion by CL strain metacyclic forms and is identified by monoclonal antibody (MAb) 3F6. Firstly, we investigated the molecular basis of the non-virulence of T. cruzi clone CL-14 metacyclic forms in vivo and in vitro. We found that the low infectivity of these parasites is associated with reduced expression of surface gp82, reinforcing the role of this molecule in T. cruzi infection. In addition, our data suggested that instead of gp82, metacyclic forms of clone CL-14, like G strain, preferentially engage gp35/50 glycoproteins to interact with the host cell. Secondly, we analyzed the expression and cellular localization of molecules of the gp82 family in T. cruzi metacyclic forms of G and CL strains. We cloned a new member of this family, designated C03, which lacks the MAb 3F6 epitope, in contrast to the previously described gp82 cDNA clones J18 (G strain) and R31 (CL strain). The predicted amino acid sequence of the C03 clone displayed 59,1% identity to J18 clone and 60,2% to R31 clone. When the amino acid sequences of C03 and Tc-85 (tissue culture trypomastigote gp85) clones were aligned, the identity was 57,2%, indicating that this new clone belongs to the gp85/trans-sialidase family. Using anti-J18 and anti-C03 polyclonal antibodies, as well as MAb 3F6, we demonstrated that members of the gp82 family are localized on the cell surface and intracellularly in metacyclic forms, and some members have different cellular localization in parasites from T. cruzi I and II groups. As opposed to metacyclic stage-specific gp82 identified by MAb 3F6, other gp82 fami ly molecules were also detected in tissue culture trypomastigotes and amastigotes by polyclonal antibodies. Thirdly, we investigated the effect of gp82, as a recombinant protein (J18), on the murine melanoma lineage Tm5. We observed that J18 binds to these cells disrupting actin filaments similarly to cytochalasin-D, drug that induces apoptosis in mammalian cells. Based on these information, we comparatively analyzed alterations in actin cytoskeleton and apoptotic events in J18-treated Tm5 cells, and in the melanocyte lineage melan-a, from which Tm5 is derived. J18 selectively induced apoptosis in Tm5 melanoma cells. Our results show an activity of a protein from gp82 family that has not been described for any other T. cruzi molecule.
TEDE

Abstract Improving the academic success and graduation rates of African-American males has been a major focus of both scholars and practitioners in the United States. Locally, African-American males at an urban Title 1 school were experiencing the lowest grade point averages, American College Test scores, and graduation rates in the district. In response to these academic declines, this study focused on the tenets of Bechtol's sports participation theory, which holds that students who play sports experience greater academic achievement and adult success in life. The purpose of this study was to examine the relationship between total hours of high school athletics participation and earned GPAs for African-American male students at the school under study for 1 academic year and across each term (4) of the school year. A correlational research design was used to identify if a relationship existed between hours of sports participation and the GPAs of African-American male student-athletes from the 2012 ' 2013 school year (N = 36). The results of the 5 Pearson correlation analyses indicated no statistically significant relationship between the total hours African-American male student-athletes spent participating in sports and their GPAs. The sample size was a limitation of the study design, therefore it was recommended to conduct the investigation with a larger sample size. The results of the study prompted the design of a professional development program for local administrators, faculty, and staff called Championing Higher Achievement Matriculation, Preparation, and Success for Student Athletes (CHAMPS). The CHAMPS program prepares school personnel to more effectively mentor, coach, tutor, and teach African-American male student-athletes. The program can improve the quality of education that can serve as the stimulus for social change through improved educational outcomes for African-American male student athletes.

Les travaux de recherche developpes dans cette these s'inscrivent dans un contexte d'activites relevant a la fois de l'intelligence artificielle et de la productique, que d'aucuns appellent productique distribuee et intelligente. Ils contribuent a l'emergence de nouveaux concepts, tant sur le plan definitoire que sur le plan operatoire, permettant de mieux apprehender la modelisation des systemes de production et, par consequence, de mieux maitriser la productique distribuee et intelligente. Nous avons introduit un nouveau concept: emd (entreprise manufacturiere distribuee). L'emd definie, a partir d'un point de vue cognitif, un modele conceptuel permettant de caracteriser deux points importants de la productique distribuee et intelligente: (i) la repartition a la fois de competences et des capacites decisionnelles de l'entreprise conduisant a la caracterisation d'unites autonomes et (ii) le developpement de strategies de cooperation entre ces unites. Pour la mise en uvre de l'emd nous avons defini un nouveau paradigme de modelisation nomme aop3s (agent oriented programming paradigm for production systems). Aop3s est oriente connaissance ; il utilise certaines notions de l'architecture cimosa (computer integrated manufacturing open system architecture) ; et enfin, il adopte les systemes multi-agents comme methodes et outils de modelisation. Aop3s dispose d'un langage de representation de connaissances oriente-objet permettant de construire des modeles operatoires a partir du modele conceptuel de l'emd. L'utilisation de ce langage a des fins de simulation est dictee par une demarche methodologique

De nos jours, la reactivite d'une entreprise depend de l'amelioration des differents modes de conduite de son systeme de production et plus particulierement de la prise en charge des perturbations. Il s'agit de proposer aux acteurs de la production un systeme de conduite capable de leur fournir une aide au cours des processus de decision qu'ils developpent. Ces processus donnent lieu a des actes pour permettre d'apporter une reponse rapide aux perturbations qu'ils rencontrent. Dans cette optique, une approche sociotechnique des systemes de production a ete retenue (notions d'acteur, de decision, de processus de decision et de relais actorial). Ensuite, compte tenu des insuffisances de certaines methodes d'analyse, nous proposons une approche complementaire qui permet de construire un systeme de conduite centre sur les acteurs. Il s'agit d'une demarche d'analyse et de representation des processus de decision correspondant a la prise en charge de perturbations, processus qui font appel a des decisions non-programmees. Afin d'appuyer cette demarche, des concepts et outils sont proposes : des criteres de caracterisation des perturbations, une classification des perturbations, un questionnaire, un formalisme pour les representations, etc. Deux cas d'application de cette demarche sont presentes, ce qui permet de mettre en evidence les apports de cette demarche. Enfin, plusieurs voies d'approfondissement ou d'elargissement de ce travail sont envisagees.

Les premiers outils de conception ou de fabrication et autres techniques assistées par ordinateur ont permis de répondre à un certain nombre de besoins en matière de modélisation et simulation numérique de produit, automatisation de tâches en production, représentation et visualisation des résultats. Immédiatement est apparue la nécessité de faire communiquer ces tâches afin de limiter le nombre d'opérations manuelles de reprise des données. Pour cela, des interfaces spécialisées furent développées : cette démarche baptisée intégration par les interfaces se traduit par le couplage entre deux ou plusieurs maillons de la chaîne CFAO. Dans notre cas, un grand nombre d'interfaces spécifiques entre la CFAO et la GPAO ont été développées : complément de la nomenclature CAO pour aboutir à une nomenclature GPAO, communication vers le logiciel d'optimisation, chiffrage des études, choix des programmes d'usinages des différents centres de production, simulation d'usinage, choix automatiques des composants d'emballage, duplication de nomenclature, mise à jour globale de gammes et de nomenclatures. . . De plus en plus de recherches sont centrées autour de la fonction méthode pour le développement de systèmes de génération de gammes en partant du modèle virtuel provenant de la CAO. C'est le but de ce mémoire axé essentiellement dans un premier temps sur les gammes destinées au chiffrage, sur les gammes d'ordonnancement, sur les gammes d'usinage. Outre la complexité du raisonnement lié au savoir-faire du gammiste que doivent supporter de tels systèmes par des techniques appropriées de représentation des connaissances, toute une panoplie de données concernant le produit et l'outil de production doit être également intégrée. Les principales contraintes sont la durée des études qui s'est vue rallongée et donc la difficulté de tenir les délais ainsi que la disposition de beaucoup de mémoire, pour pouvoir manipuler un tel flot d'informations.

Photoacclimation is a process by which photosynthetic capacity is regulated in response to environmental adjustments in terms of light regime. Photoacclimation is essential in determining the photosynthetic capacity to optimize light use and to avoid potentially damaging effects. Previous work in our laboratory has identified a gene, gpt2 (At1g61800) that is essential for plants to acclimate to an increase in growth irradiance. Furthermore, we observed that the accession Columbia-0 (Col-0) is unable to respond to increases in light. Therefore, a Quantitative Trait Locus (QTL) mapping analysis was performed in Landsberg erecta (Ler)/Columbia (Col) recombinant inbred line population to identify novel genes responsible for this variation to acclimation. In order to investigate the photoacclimation in Arabidopsis thaliana, photosynthetic capacity was measured in plants of the accession Wassileskija (WS) and in plants lacking expression of the gene At1g61800 (WS-gpt2) during acclimation from high to low light. Plants were grown for 6 weeks under high light (400 μmol.m-2.s-1) and half of them were transferred to low light (100 μmol.m-2.s-1) after six weeks. Gas exchange measurements were performed in order to measure the maximum capacity for photosynthesis. Acclimation to a decrease in light resulted in a decrease in the photosynthetic capacity in WS and WS-gpt2 plants. This shows that under lower or limiting light, photosynthesis was slowed down. Chlorophyll fluorescence analysis was carried out to measure changes in the quantum efficiency of PSII (ΦPSII) and non-photochemical quenching (NPQ) during acclimation. ΦPSII decreased in both WS and WS-gpt2 plants showing that under low light, PSII is more saturated. However, it was found that there was no significant changes in NPQ level for both WS and WS-gpt2. To estimate the total chlorophyll and chl a/b ratio, a chlorophyll composition analysis was performed. There was no significant changes in the total chlorophyll for both WS and WS-gpt2. However, the chlorophyll a/b ratio was seen to be decreased in low light plants representing an increase in light harvesting complexes relative to reaction centre core. Plants of WS and WS-gpt2 were also grown under natural variable light in an unheated greenhouse in Manchester, UK. This experiment was carried out to study the photosynthetic acclimation of plants under fluctuating light condition. A preliminary work on gene expression of gpt2 was conducted by doing reverse transcriptase PCR (RT-PCR). It shows that the gene expression of gpt2 decreased following transfer to low light plants in WS. Microarray analysis was also performed to investigate the role of GPT2 (if any) and to identify any potential gene that is important in high to low light acclimation.

La symbiose mycorhizienne à arbuscules (AM) est une association entre la plupart des embryophytes et des champignons ubiquitaires du sol qui appartiennent à la famille des Glomeromycotina. La symbiose mycorhizienne a été proposé comme l'une des innovations clés qui ont permis la colonisation de la terre par des plantes il y a 450 millions d'années. Les champignons mycorhiziens colonisent leur hôte de façon interne et produisent des structures intracellulaires, appelées arbuscules, où ils fournissent de l'eau et des nutriments minéraux à leur hôte en échange de carbone sous forme de sucres et de lipides. Chez les angiospermes, des études récentes ont permis de mieux comprendre les mécanismes moléculaires à l'origine de l'établissement de la symbiose mycorhizienne et des échanges trophiques. Les lipides ont été identifiés comme étant une des principales sources de carbone transférée au partenaire fongique qui est auxotrophe pour les lipides. Une voie de biosynthèse des lipides associée à la symbiose limité dans son expression dans les cellules colonisées par les champignons AM a été caractérisé chez des plantes modèles. Cependant, les études génétiques ont jusqu'à présent été limitées à quelques espèces d'angiospermes. Nous avons utilisé ici le modèle d'hépatique Marchantia paleacea, récemment mis au point, pour vérifier si les mécanismes permettant le transfert des lipides de la plante au champignon ont une origine profonde dans les plantes ou ont évolué plus récemment chez les Angiospermes. Premièrement, nous avons observé une accumulation de lipides dans les cellules de M. paleacea contenant des arbuscules. Ensuite, une stratégie originale basée sur l'ingénierie enzymatique nous a permis de suivre des composés lipidiques spécifiques supposés être transférés au champignon. De cette manière, nous avons démontré la production de lipides et leur transfert de M. paleacea au champignon mycorhizien Rhizophagus irregularis. La conservation de ce transfert, qui avait été initialement démontrée dans les angiospermes, souligne son importance dans la symbiose mycorhizienne. Grâce au génome récemment séquencé de M. paleacea, nous avons identifié chez cet organisme les gènes connus chez les angiospermes comme étant impliqués dans la biosynthèse et le transfert de lipides symbiotiques. [...]
The Arbuscular Mycorrhiza (AM) symbiosis is an association between most embryophytes and ubiquitous soil-born fungi that belong to the Glomeromycotina. It has been proposed as one of the key innovation that allowed the colonization of land by plants 450 million years ago. AM fungi colonize internally their host and produce intracellular structures, called arbuscules, where they provide water and mineral nutrients to their host in exchange for carbon delivered as sugars and lipids. In angiosperms, recent studies have provided a deeper understanding of the molecular mechanisms behind AM establishment and trophic exchanges. Lipids have been identified as the main carbon source transferred to the fungal partner which is lipid auxotroph. The associated symbiotic lipid-biosynthesis pathway expressed in cells colonized by AM fungi have been deciphered in model plants. However, genetic studies have so far been limited to a few angiosperm species. Here, we used the model liverwort Marchantia paleacea, recently developed, to test whether the mechanisms that allow the transfer of lipids from the plant to the fungus have a deep origin in plants or evolved more recently in Angiosperms. First, we observed lipid accumulation in the arbuscule-containing cells of M. paleacea. Then, an original strategy based on enzymatic engineering allowed us to follow the fate of specific lipid compounds believed to be transferred to the fungus. By this way, we demonstrated the production of lipids and their transfer from M. paleacea to the AM fungus Rhizophagus irregularis. The conservation of this transfer, that had been originally demonstrated in angiosperms, outlines its importance in the AM symbiosis. Thanks to the recently sequenced genome of M. paleacea, we identified in this organism the genes known in angiosperms as being involved in the symbiotic lipid biosynthesis and transfer pathway. I focused on one essential gene encoding for the Glycerol-3 Phosphate Acyl Transferase RAM2 which is thought to act downstream of this pathway. Promoter GUS analysis of M. paleacea RAM2, indicated that its expression was induced in arbuscule-containing cells. [...]

Thesis (M.S. in Ed.)--Southern Illinois University Carbondale, 2005.
"Department of Educational Psychology and Special Eduation." Includes bibliographical references (leaves 57-62 ). Also available online.

The goal of this research was to examine the effects, if any, the programs available from an Academic Support Services unit of a small, private, liberal arts college might have on the grade point averages of students admitted on probation over two major semesters. The assumption was that the students who utilized the services of the Academic Center for Excellence would demonstrate more increases in GPA than students who did not utilize the services. The literature review of this study found that, although there were many factors and student characteristics that could predict and explain student achievement in course work, GPA was a good predictor and the only real measure of a student's performance. The programs designed to offer support are demonstrated to aid students in improving their academic achievement. The results of this study suggest that GPA is a good predictor of a student's academic achievement and a primary method of assessing student academic achievement. However, there was no apparent impact of the support services unit on the grade point averages of the students admitted on probation. Suggested uses for the study included the development of freshman orientation programs that integrate the student into academic life and a retooling of counseling and advising programs.
Ed.D.
Department of Educational Research, Technology and Leadership
Education
Educational Leadership

Bei der Entdeckung der Glutathionperoxidase-2 (GPx2) wurde zunächst davon ausgegangen, dass die Funktion dieses Enzyms im Kryptengrund des Colons einzig in der Reduktion von H2O2 besteht. Im Laufe der weiteren Erforschung zeigte sich, dass GPx2 auch in verschiedenen Tumorgeweben vermehrt exprimiert wird. Dabei wird diskutiert, ob die Wirkung von GPx2 im Tumor eher als pro- oder als antikarzinogen einzustufen ist. Mehrere Experimente in vitro und in vivo zeigten antiinflammatorische Eigenschaften der GPx2. Aufgrund dieser Befunde wird derzeit über weitere Funktionen der GPx2 spekuliert. In dieser Arbeit wurde die physiologische Funktion von GPx2 näher erforscht, dazu wurden Wildtyp- und GPx2-Knockout-Mäuse in Hinblick auf Veränderungen der Enzymexpression und der Colonmorphologie untersucht. Es wurden drei verschiedene Selendiäten verfüttert: selenarmes, selenadäquates und selensupplementiertes Futter. Unter physiologischen Bedingungen ist am Kryptengrund des Colons, innerhalb der proliferierenden Zone, die Mitoserate am höchsten. Der Großteil der apoptotischen Zellen ist hingegen an der Kryptenspitze vorzufinden. Durch den Knockout von GPx2 kam es zu einer signifikanten Erhöhung der Apoptoserate am Kryptengrund. Dabei war der größte Effekt auf selenarmem Futter zu verzeichnen. Hierbei wurde sogar eine Veränderung der Colonmorphologie dokumentiert, da die Verschiebung der Proliferationszone in Richtung Kryptenspitze eine Verlängerung der Krypten nach sich zog. Im Wildtyp wurden keine Apoptosen im Kryptengrund detektiert. GPx1 wird unter physiologischen Bedingungen im Gegensatz zur GPx2 in der Kryptenspitze exprimiert und ist im Selenmangel nicht mehr detektierbar. Der Knockout von GPx2 erhöhte die GPx1-Expression im Kryptengrund auf allen drei Selendiäten. Diese Überexpression von GPx1 am Kryptengrund soll vermutlich den Verlust von GPx2 an dieser Stelle kompensieren. Da jedoch dort die massive Apoptoserate detektiert wurde, kann die GPx1 nicht die komplette Funktion von GPx2 kompensieren. Diese Ergebnisse deuten darauf hin, dass die Funktion von GPx2 nicht nur in der Reduktion von H2O2 liegt. Vielmehr kann eine Rolle bei der Aufrechterhaltung der Homöostase von Zellen postuliert werden. Ein weiterer Bestandteil dieser Arbeit war die Klärung der Frage, welchen Einfluss GPx2 auf die entzündungsassoziierte Colonkarzinogenese ausübt. In dem hierfür verwendeten AOM/DSS-Model wird der karzinogene Prozess durch Entzündung vorangetrieben. Es erfolgte sowohl im Wildtyp als auch im GPx2-Knockout zum einen die Bewertung des Entzündungsstatus des Colons und zum anderen wurde die Anzahl von ACF und Tumoren verglichen. Das Colon im GPx2-Knockout war wesentlich stärker entzündet als im Wildtyp. Diese Ergebnisse bestätigen die für die GPx2 postulierte antiinflammatorische Funktion. Normalerweise führt eine Erhöhung der Mitoseanzahl zur Regeneration des entzündeten Gewebes. Jedoch beeinflusst der Verlust von GPx2 vermutlich den Ablauf der Entzündung, indem beispielsweise die Regeneration des Gewebes durch die enorm hohe Apoptoserate am Kryptengrund verlangsamt wird. Des Weiteren hatten sich im GPx2-Knockout tendenziell mehr Tumore entwickelt. Somit korrelierte die Entzündung des Colons mit der Entwicklung von Tumoren. Der Verlust von GPx2 begünstigte vermutlich sowohl die Tumorinitiation als auch die Tumorprogression. Allerdings stimulierte die Expression von GPx2 ebenfalls das Tumorwachstum. Es kann geschlussfolgert werden, dass eine adäquate GPx2-Expression vor Entzündung schützt und somit das Risiko für Colonkrebs senkt. Ob GPx2 aber insgesamt pro- oder antikarzinogen wirkt, hängt vermutlich vom Stadium des Colonkarzinogenese ab.
Since the detection of glutathione peroxidase-2 (GPx2) it was assumed that reducing hydroperoxides is the only function of this enzyme in the crypt ground of the colon. But further studies showed that GPx2 is also highly expressed in tumor tissue. However, it is not known whether it acts a pro- or anticarcinogenic manner at this site. In vitro and in vivo experiments elucidate antiinflammatory features of GPx2, based on these findings additional functions of GPx2 are discussed. In this dissertation the physiological function of GPx2 was investigated. For this purpose in wild type and GPx2-knockout mice, changes of enzyme expression and colon morphology were analyzed. The mice were fed three diets containing different selenium concentrations: selenium deficient, selenium adequate and selenium supplemented. Under physiological conditions the mitosis rate is highest in the proliferating zone in the crypt ground of the colon. The majority of apoptotic cells are located at the tip of the crypt. The knockout of GPx2 significantly increased the rate of apoptosis in the crypt ground. The greatest effect was documented on the selenium deficient diet. Here, changes of the colonic morphology were detectable, because the shift of the proliferating zone towards the tip of the crypt lead to an extension of the crypts. In the wild type mice no apoptotic cells were detected on the crypt ground. Under physiological conditions GPx1, in contrast to GPx2, is mainly expressed on the top of the crypt, and this enzyme is no longer detectable under selenium deficiency. The knockout of GPx2 increased the expression of GPx1 in the crypt ground of the colon on all three selenium diets. It is likely that this over expression of GPx1 compensates for the loss of GPx2. However the massive apoptotic rate in the crypt ground shows that GPx1 can not compensate the complete function of GPx2. These results elucidate that GPx2 not only functions as a hydroperoxide reducer, but that it is also important for the maintenance of the stem cell character and the homeostasis of cells. The question if GPx2 influences the inflammation triggered by the coloncarcinogenic process was next assessed in this dissertation. Therefore the AOM/DSS model was used to trigger the carcinogenic process through inflammation. The amount of aberrant crypt foci (ACF) and tumors in the colon were analyzed in both wild type and GPx2-knockout mice. However initially the inflammation status was compared between the two genotypes. The inflammation of the colon was stronger in the GPx2-knockout mice than in wild type. These results support the postulated antiinflammatory features of GPx2. The loss of GPx2 may influence the inflammation process by decelerating the regeneration of the tissue caused by the increased apoptotic rate in the proliferating zone. Additionally, the GPx2-knockout mice developed more tumors in the colon. Therefore the inflammation of the colon correlated with the development of tumors. The loss of GPx2 may have enhanced both tumor initiation and progression. But the expression of GPx2 also stimulated the growth of tumors. These results indicate that an adequate GPx2-expression can protect from colonic inflammation, and therefore decrease the risk of developing colon cancer. Whether GPx2 acts in a pro- or anticarcinogenic manner appears to depend on the state of the carcinogenic process.

This study investigated the strategies academically successful college student athletes use to do well in their class work, where academic success was defined as a 3.5 GPA for 12 or more credits for the two semesters preceding the study. Data were transcriptions of individual interviews with five male and five female athletes in seven sports at an NCAA Division I university in the western United States. Independent coders analyzed the data and agreed upon themes related to challenges to academic success and strategies to meet those challenges. Findings add to the literature by detailing self-regulatory habits that academically underprepared athletes can adopt from their successful peers. Academic advisors can use these findings as they help athletes increase academic success and learn valuable life skills.

Made available in DSpace on 2015-12-06T23:47:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2008
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Os tripomastigotas metacíclicos de Trypanosoma cruz; expressam as glicoproteínas de superfícies GP82 e GP90 de maneira estágio-específica, as quais estão implicadas na invasão da célula hospedeira. Embora as proteínas não sejam expressam e os RNAm GP82 e GP90 fracamente detectáveis em epimastigotas, ensaios de transcrição em núcleos isolados mostraram que eles são transcritos constitutivamente nos dois estágios. Este resultado indica que o acúmulo de transcritos nas formas metacíclicas não é devido a um aumento na transcrição dos genes GP82 e GP90. Para investigar se a estabilidade dos RNAm seria a responsável pelas diferenças nos níveis destes RNAm, parasitas foram tratados com actinomicina D ou cicloheximida. Quando tratados com actinomicina D, as meia-vidas dos transcritos GP82 e GP90 foram maiores que 8 h em tripomastigotas metacíclicos e menor que 0,5 h e 2 h em epimastigotas, respectivamente. Na presença de cicloheximida, os níveis de RNAm GP82 e GP90 caíram levemente, enquanto que em epimastigotas os níveis destes RNAm aumentaram após 8 h de tratamento. Este efeito sugere um mecanismo de estabilização atuando em tripomastigotas metacíclicos e de desestabilização em epimastigotas, os quais parecem ser mediados por elementos presentes na 3' -UTR destes transcritos. Nós mostramos que a 3'-UTR da GP82 gera uma expressão maior do gene repórter GFP em tripomastigotas metacíclicos do que em epimastigotas. Consistente com este achado, análises de "northern blot" mostram que os RNAm GP82 e GP90 são mobilizados para os polissomas e conseqüentemente traduzidos apenas em tripomastigotas metacíclicos. Estes resultados sugerem que a estabilidade destes RNAm envolve interações com elementos regulatórios positivos e negativos na 3' -UTR. Estudos para melhor compreensão dos mecanismos envolvidos na estabilidade dos RNAm GP82 e GP90 estão em progresso em nosso laboratório.
Trypanosoma cruzi metacyclic trypomastigotes express the developmentally regulated GP82 and GP90 glycoproteins, which are implicated in host cell invasion. Although GP82 and GP90 mRNAs and proteins are not present and the mRNAs barely detectable in epimastigotes, nuclear run-on analysis showed that they are transcribed in both stages. This result indicates that accumulation of transcripts in metacyclic forms is not due to increased transcription of the GP82 and GP90 genes. To investigate whether mRNA stability may be responsible for the differences in the steady-state levels of these mRNAs, parasites were treated with actinomycin D or cycloheximide. When treated with actinomycin D, the half-lives estimated for GP82 and GP90 transcripts were longer than 8 h in metacyclic trypomastigotes and less than 0.5 h and 2 hours in epimastigotes, respectively. In the presence of cycloheximide, the levels of GP90 and GP82 mRNA decayed slightly after 8 h in metacyclic trypomastigotes, whereas in epimastigotes the levels of these mRNAs increased. This effect suggests a stabilizing mechanism acting in metacyclic trypomastigotes and a destabilizing mechanism in epimastigotes which could be mediated by an element present in the 3’-UTR of the transcripts. We show that the 3’-UTR of GP82 causes higher expression of the green fluorescent protein reporter gene in metacyclic trypomastigotes than in epimastigotes. Consistent with this finding, northern blot analysis showed that GP82 and GP90 mRNAs were mobilized to polysomes and consequently translated, but only in metacyclic trypomastigotes. These results suggest that the stability of these mRNAs involves interactions between positive and negative regulatory elements in the 3’-UTR. Work is ongoing to better understanding the mechanisms involved in changes in GP82 and GP90 mRNA stability.
BV UNIFESP: Teses e dissertações

This study shows that Arabidopsis thaliana WRKY45 gene has an important role in limiting green peach aphid (GPA; Myzus persicae Sülzer) infestation. WRKY45 belongs to the WRKY family of transcription factors, which is one of the largest transcription factor family in plants. In response to GPA infestation, expression of WRKY45 was systemically upregulated in leaves and roots, with highest expression in the vascular tissues, which are the site of aphid feeding. GPA colonization was better on the wrky45 mutant compared to the wild-type (WT) plant. In contrast, GPA poorly colonized plants that were overexpressing (OE) WRKY45, thus confirming an important role for WRKY45 in plant defense to the GPA. A WRKY45-dependent process adversely impacted the reproductive rate of GPA and feeding from the sieve elements. RNA-seq experiments indicated a major impact of WRKY45 overexpression on expression of genes associated with dehydration and abscisic acid biosynthesis and signaling. In agreement with the RNA-seq data, ABA content was also higher in WRKY45-OE plants. However, genetic studies with an ABA-insensitive mutant (abi2-2) indicates that the WRKY45-OE conferred resistance to GPA is mediated through an ABA-independent mechanism. WRKY45-OE plants showed enhanced tolerance to drought and salt stresses. Genetic studies indicate that ABA signaling is critical for WRKY45's involvement in promoting plant tolerance to drought. Taken together, these results demonstrate that WRKY45 acts as a positive regulator of plant responses to GPA infestation, and drought and salt stress responses.

The development of all organs of the plant depends on the activity of the meristems and adjacent areas. Monocarpic plants show only one reproductive cycle before they senescence and die. The senescence and death of these plants is preceded by a global proliferative arrest of meristems (GPA). That way, the number of fruits/flowers that they produce during their lives depends on the proliferative activity of apical meristems of the branches and on the time GPA occurs. The study of the mechanisms that control GPA, as well as a better knowledge of genes involved in the maintenance of merismatic cells during this process, can provide useful tools for crop breeding programs in order to obtain more productive varieties. The GPA is a phenomenon described more than a century ago for some monocarpic plants. Different hypothesis have been set out about the factors that trigger it. Among the factors than might be involved, the existence of source-sink relationships or the regulation of the meristem activity by the reproductive organs in development have been proposed. Regarding reproductive organs, a signalling role of developing seeds is well established, as in sterile plants or in plants where fruits are continuously pruned the GPA is significantly delayed. In our group, it has been recently described the first genetic pathway proposed to regulate the longevity of the meristem in monocarpic plants. This pathway includes transcription factors such as FRUITFULL (FUL) and APETALA2 (AP2) to control the temporal onset of this process in Arabidopsis thaliana. Our model proposes that levels of expression of miR172 and FUL increase with the age of the plant as consequence of the decrease of miR156 and the upregulation of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPLs) transcription factors. The increase of the expression of FUL and miR172 causes the downregulation of AP2, which causes the progressive decrease of WUSCHEL (WUS) expression, and therefore, the cessation of meristematic activity and appearance of GPA. In the first chapter of this PhD thesis, we have aimed to gain further knowledge in the study of longevity control of the meristems by the FUL-AP2 pathway, identifying molecular targets or interactors of AP2. In the second chapter, we have screened different mutagenized populations for mutants that show early GPA while been sterile, as a starting point to the identification of factors potentially involved in the signalling mechanism between developing seeds and the apical meristem, one the proposed pathways for GPA regulation. In the third chapter, we have developed several biotechnological strategies to increase the production of fruits and seeds in Arabidopsis thaliana. These strategies aim to apply the knowledge we have gained about the FUL-AP2 pathway for the control of meristem activity to delay GPA. All the strategies converge in increasing AP2 expression specifically in the SAM. For this, specific promoters of this tissue have been used to either to silence FUL or to impair miR172 activity. Through these strategies, we have achieved to increase fruit production in Arabidopsis up to 40%. Finally, in the fourth chapter we have analysed the functional conservation of FUL in Pisum sativum. After the characterization of the fula and fulb mutants, we have observed that in fulb mutant, GPA is delayed, increasing the production of reproductive nodes and therefore of pods without any additional developmental defects. Our results show the conservation of FUL role in GPA regulation between brassica and legumes.
El desarrollo de todos los órganos de la planta depende de la actividad de los meristemos y regiones adyacentes. Las plantas monocárpicas presentan un único ciclo reproductivo antes de su senescencia y muerte. La senescencia y muerte de estas plantas está precedida por una parada global de la proliferación de sus meristemos (GPA). De este modo, el número de flores/frutos que producen durante su vida depende de la actividad proliferativa de los meristemos apicales de las ramas y de cuando se produzca el GPA. El estudio de los mecanismos que controlan el GPA, así como un mayor conocimiento de los genes implicados en el mantenimiento de las células meristemáticas durante este proceso, proporcionaría herramientas muy útiles en los programas de mejora de cultivos para la obtención de variedades más productivas. EL GPA es un fenómeno descrito hace más de un siglo para varias plantas monocárpicas, y se han planteado diferentes hipótesis sobre los factores que lo desencadenan. Entre los factores propuestos se encuentran la existencia de relaciones fuente-sumidero o la regulación de la actividad meristemática por parte de los órganos reproductivos en desarrollo. Respecto al papel de los órganos reproductivos está bien definido un papel señalizador de las semillas en desarrollo, ya que la esterilidad de la planta o la poda de los frutos retrasan considerablemente el GPA. Por otro lado, en nuestro grupo se ha desvelado recientemente la que es probablemente la primera ruta genética propuesta de regulación de la longevidad del meristemo en plantas monocárpicas, y que incluye a los factores transcripcionales FRUITFULL (FUL) y APETALA2 (AP2) en el control temporal de este proceso en Arabidopsis thaliana. Esta ruta propone que con la edad los niveles de expresión del miR172 y de FUL aumentan como consecuencia de la reducción del miR156 y aumento de los factores de transcripción SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPLs), que regulan la expresión de FUL. El aumento de la expresión de FUL y del miR172 produce la reducción de los niveles de AP2, que ocasiona la progresiva disminución de la expresión del gen de mantenimiento meristemático WUSCHEL (WUS), y por tanto, el cese de la actividad meristemática y aparición del GPA. En el capítulo 1 de esta tesis doctoral se ha pretendido profundizar en el estudio del control de la longevidad de los meristemos mediante la ruta FUL-AP2, identificando dianas moleculares o interactores de AP2. En el capítulo 2 hemos llevado a cabo el rastreo de diferentes poblaciones mutagenizadas buscando mutantes que a pesar de ser estériles tuvieran un GPA temprano, como punto de partida a la identificación de factores implicados en la vía de señalización entre semillas en desarrollo y meristemo apical, otra de las posibles rutas de regulación del GPA. En el capítulo 3 hemos desarrollado una serie de estrategias biotecnológicas que permiten aumentar la producción de frutos y semillas en Arabidopsis thaliana. Estas estrategias tratan de aplicar el conocimiento sobre la ruta FUL-AP2 de mantenimiento de la actividad meristemática para retrasar el GPA. Todas las estrategias convergen en elevar el nivel de expresión de AP2 únicamente en el SAM. Para ello, se han empleado promotores específicos de este tejido, dirigiendo el silenciamiento de FUL o la desregulación de la actividad del miR172. Mediante estas estrategias hemos conseguido incrementar la producción de frutos en la inflorescencia principal de Arabidopsis hasta en un 40%. Por último en el capítulo 4 hemos analizado la conservación funcional de FUL en Pisum sativum. Tras la caracterización de los mutantes fula y fulb, observamos como en el mutante fulb se retrasa el GPA, incrementando la producción de nudos reproductivos, y por tanto de vainas sin que estas muestren defectos en su desarrollo. Los resultados obtenidos indican una clara conservación del papel de FUL en el GPA entre brásicas y leguminosas.
El desenvolupament de tots els òrgans de la planta depèn de l'activitat dels meristems i regions adjacents. Les plantes monocàrpiques presenten un únic cicle reproductiu abans de la seua senescència i mort. La senescència i mort d'aquestes plantes està precedida per una parada global de la proliferació dels seus meristems (GPA). D'aquesta manera, el nombre de flors/fruits que produeixen durant la seua vida depèn de l'activitat proliferativa del meristem apical de la tija i de quan es produeix el GPA. L'estudi dels mecanismes que controlen el GPA, així com un major coneixement dels gens implicats al manteniment de les cèl·lules meristemàtiques durant aquest procés, proporcionaria eines molt útils en els programes de millora de cultius per a l'obtenció de varietats més productives. EL GPA és un fenomen descrit fa més d'un segle per a diverses plantes monocàrpiques, i s'han plantejat diferents hipòtesis sobre els factors que el desencadenen. Entre els factors proposats es troben l'existència de relacions font-sumider o la regulació de l'activitat meristemàtica per part dels òrgans reproductius en desenvolupament. Pel que fa al paper dels òrgans reproductius està ben definit un paper senyalitzador de les llavors en desenvolupament, ja que l'esterilitat de la planta o la poda dels fruits retarda considerablement el GPA. D'altra banda, en el nostre laboratori s'ha revelat recentment la que és probablement la primera ruta genètica proposta de regulació de la longevitat del meristem en plantes monocàrpiques, i que inclou els factors transcripcionals FRUITFULL (FUL) i APETALA2 (AP2) en el control temporal d'aquest procés en Arabidopsis thaliana. Aquesta ruta proposa que amb l'edat els nivells d'expressió del miR172 i de FUL augmenten com a conseqüència de la reducció del miR156 i augment dels factors de transcripció SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPLs), que regulen l'expressió de FUL. L'augment de l'expressió de FUL i del miR172 produeix la reducció dels nivells de AP2, que ocasiona la progressiva disminució de l'expressió del gen de manteniment meristemàtic WUSCHEL (WUS), i per tant, el cessament de l'activitat meristemàtica i aparició del GPA. En el capítol 1 d'aquesta tesi doctoral s'ha pretès aprofundir en l'estudi del control de la longevitat dels meristems mitjançant la ruta FUL-AP2, identificant dianes moleculars o interactors de AP2. En el capítol 2 hem dut a terme el rastreig de diferents poblacions mutageneizadas buscant mutants que tot i ser estèrils tingueren un GPA temprà, com a punt de partida a la identificació de factors implicats en la via de senyalització entre llavors en desenvolupament i meristem apical, una altra de les possibles rutes de regulació del GPA. En el capítol 3 hem desenvolupat una serie d'estratègies biotecnològiques que permeten augmentar la producció de fruits i llavors en Arabidopsis thaliana. Aquestes estratègies intenten aplicar el coneixement sobre la ruta FUL-AP2 de manteniment de l'activitat meristemàtica per retardar el GPA. Totes les estratègies convergeixen en elevar el nivell d'expressió de AP2 únicament en el SAM. Per açò, s'han emprat promotors específics d'aquest teixit, dirigint el silenciament de FUL o la desregulació de l'activitat del miR172. Mitjançant aquestes estratègies hem aconseguit incrementar la producció de fruits en la inflorescència principal d'Arabidopsis fins un 40%. Finalment en el capítol 4 hem analitzat la conservació funcional de FUL en Pisum sativum. Després de la caracterització dels mutants fula i fulb, observarem com en el mutant fulb es retardava el GPA, incrementant la producció de nusos reproductius, i per tant de baines, sense que aquestes mostraren defectes en el seu desenvolupament. Els resultats obtinguts indiquen una clara conservació del paper de FUL al GPA entre brasicas i lleguminoses.
Martinez Fernandez, I. (2017). La ruta FUL-AP2 y la longevidad de los meristemos en Arabidopsis thaliana. Bases moleculares y potencial biotecnológico [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/88394
TESIS

Après avoir fait un état de l'art en gestion de production assistée par ordinateur (gpao) et une étude critique des principaux progiciels existants, on propose une nouvelle approche qui permet de découpler l'optimisation des temps de cycles et des encours de celle du retard, le but étant de produire juste à temps. D'autre part on présente une typologie des ateliers d'usinage et une étude de l'adéquation des règles de conduite aux types d'atelier et de production habituellement rencontrés.

Meiosis is a specialized cell division, producing unique daughter cells containing half the chromosome number of the parental cell. In the hermaphroditic nematode C. elegans, meiotic mutants can be recognized by embryonic lethality (Emb) and high incidence of males (Him) phenotypes due to chromosome missegregation. In search of new meiotic mutants, we isolated vv33 in an EMS-based "Green eggs and Him" screen (Kelly et al. 2000; Tom Nolis, unpublished data). DAPI stainings of vv33 mutant gonads reveal unusually large nuclei and micronuclei throughout the germline. Characterization suggests that defects in cell division and chromosome segregation in mitotic germ cells are transmitted through the meiotic cell cycle, resulting in 80% Emb and 7% Him. Cloning of vv33 identified it as a novel allele of gpa-16, a Gα protein with known functions in mitosis in the early embryo (Gonczy 2002). Based on our observations, we hypothesize that there is a germline-specific requirement for GPA-16.
La méiose est une division cellulaire spécialisée qui produit des cellules filles haploides à partir de cellules parentales diploides. Chez le nématode hermaphrodite C. elegans, des anomalies de ségrégation des chromosomes lors de la méiose donnent lieu à des phénotypes de létalité embryonnaire (Emb) et d'augmentation du nombre de males (Him). Lors d'un crible génétique basé sur la recherche de nouveaux mutants him (Tom Nolis, non publié), nous avons isolé l'allèle vv33. Une analyse cytologique par coloration DAPI des gonades du mutant vv33 à révélé la présence de noyaux de tailles irrégulières. De plus, des études ont mis en évidence des défauts de ségrégation des chromosomes dans les cellules mitotiques de la lignée germinale. Les anomalies chromosomiques sont ensuite héritées par les cellules méiotiques et génèrent 80% de létalité embryonnaire. Le clonage de vv33 à permit d'identifier une mutation dans le gene gpa-16, qui code une sous-unité alpha d'une protéine G précédemment décrite pour son rôle dans la mitose embryonnaire (Gonczy 2002). Nos résultats nous permettent donc d'envisager une nouvelle fonction spécifique pour GPA-16 dans la lignée germinale.

Researchers have suggested that the college student population in the United States is evolving and the number of nontraditional students is rising. New student retention and academic success were ongoing concerns at a college in the southern United States and the association of those outcomes with instructional delivery model and student type was not known. In an effort to improve new student outcomes, this study examined differences in first-quarter student retention and academic success, as measured by GPA, for courses taught strictly online or on campus, and for traditional versus nontraditional students. Guided by Bean and Metzner's conceptual model of nontraditional student attrition, this quasi-experimental study used data from 1,304 first-quarter students divided into 4 equal groups (n = 326). Groups were compared for GPA using 2x2 factorial ANOVA and for retention using chi-square tests of association. Findings showed no significant differences in retention or in the interaction between instructional delivery model and student type for GPA. A significant difference in GPA between traditional and nontraditional students, with the latter earning higher grades, was found. In addition, a bimodal grade distribution was identified in all 4 sample groups indicating the highest frequencies of students earning As and Fs, suggesting that new students either do very well or very poorly academically. Based on these findings, a white paper and presentation for campus officials was developed. The implementation of rubrics in all campus-based courses along with continuous evaluation of student performance was recommended. Positive social change may result from the use of rubrics with the new student population by increasing consistency of grading and improving understanding of expectations which may lead to better student outcomes over time.

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS), occurring in isolated attacks or progressive forms. Many observations implicate Epstein-Barr virus (EBV) in the pathogenesis of MS. With the relentless accumulation of evidence for a significant pathogenic role of EBV in MS, I believe it may be possible to prevent and cure MS by effectively controlling EBV infection. Currently, monoclonal antibodies (MAb) are used as therapeutics for a molecular targeted approach to slowing disease progression in MS. However, to my knowledge, there have been no antibodies targeted against EBV infection in any model of MS. The objective of this study is to determine whether or not a MAb against EBV could be a therapeutic target for EAE. In this study, I will propose an experiment that will examine the effects of intraperitoneal injection of MAb F-2-1 in 2-month-old new humanized BALB/c Rag2-/- ll2rg-/- (BRG) adult EBV/EAE male mice. My expected results suggest that mice with EBV/EAE + MAb F-2-1 may have an attenuated clinical disease course. Through immunohistochemical studies, I will also propose that MAb F-2-1 may decrease inflammation, demyelination and axonal loss in the CNS of mice with EAE. I believe that this novel treatments success would depend on MAb F-2-1’s ability to inhibit clonal expansion of EBV-infected autoreactive B cell in the CNS. Ultimately, my proposed experiment suggests that inhibition of virus-cell fusion of EBV to the B cell membrane might attenuate neuropathology in EAE. I hope that my prospective study highlights the importance of controlling EBV in patients with MS and provides grounds for optimism on how to successfully treat MS by controlling EBV infection. In conclusion, by proposing an alternative therapeutic approach, I hope that this hypothetical experiment will aid in future investigations that could further our knowledge on treatment and prevention of multiple sclerosis

Ce travail porte sur la qualite des donnees manipulees en gestion de production. Il s'appuie sur une analyse effectuee dans quatre entreprises de la region. Elles connaissent le meme souci avec la qualite de leurs donnees techniques et ne savent pas comment estimer l'importance de la non qualite des donnees. Pour proposer une reponse a ces problemes, nous avons travaille sur quatre points importants. Une terminologie sur les dimensions de la qualite des donnees. Nous presentons les dimensions de la qualite des donnees selon 2 axes: la qualite du modele et la qualite des valeurs. Nous insistons sur la semantique des donnees: durant le cycle de vie d'une bd et selon son mode d'introduction dans l'entreprise. Une analyse de la qualite des donnees sur les bdt. Nous decrivons les causes majeures de la mauvaise qualite des donnees techniques et analysons l'influence de celle-ci sur les principaux traitements de la gpao. Nous montrons que le contexte dans lequel la bdt a ete developpee n'est pas neutre au regard de la semantique des donnees. Une etude des correlations entre qualite des donnees et resultats d'algorithmes. Dans les cas particuliers de l'ordonnancement en flow shop et du calcul de la quantite economique, nous montrons qu'il est possible de definir une politique de maintenance des donnees a partir d'un seuil de degradation des resultats. Une derive assez importante des donnees semble necessaire pour degrader considerablement les resultats. Une demarche d'evaluation et d'amelioration de la qualite des bdt. Nous presentons une demarche d'audit permettant de faire le point sur le niveau actuel de la qualite d'une bdt. Un exemple d'application industrielle illustre cette demarche. Les choix effectues lors de l'installation de la bdt peuvent etre remis en cause

Automatisation progressive de l'outil de production en 2 phases : automatisation de machines par commande numérique, mise en place de moyens informatiques pour l'aide à la conception des pièces et la préparation des programmes d'usinage, ainsi que pour la gestion de production, en ce qui concerne la 1ère étape, et intégration de cet ensemble par mise en place d'un système de communication couvrant les ateliers et le bureau des méthodes, dans un 2ème temps

Granulomatosis with Polyangiitis (GPA) is a granulomatous inflammatory disease. It is generally described as a systemic disorder which can present with a localized presentation like the orbit. Orbital GPA can be the initial manifestation of GPA where over time the disease may progress and become severe, involving vital organs. This study aimed to look for biomarkers in orbital GPA biopsies that could indicate diagnosis and be a predictor for the progression of the disease. To identify GPA patients, retrospective examination of patients’ medical records, who had undergone orbital biopsies for orbital inflammatory disease (OID), over a 21 year period, was performed. Long term outcomes of these patients were studied. Further subjective and objective histology analyses were done on haemotoxylin and eosin (H&E) tissue preparations. Comparison of cellular activity in biopsies of GPA and other OID were performed. Further T cells, B cells and macrophage phenotypes and their cytokines, were investigated with immunohistochemistry (IHC). IHC cell count comparisons were performed between GPA, sarcoidosis and idiopathic inflammatory orbital diseases (IIOD) biopsies. Results showed that in patients who presented with orbital GPA with no systemic manifestations, the disease remained localised and did not progress to systemic form, over time. H&E tissue biopsies examination showed that GPA tissues had a higher cellular activity compared to OIDs. Vasculitis and necrosis were found to be independently associated with the diagnosis of orbital GPA but these features were unreliable for diagnosis as a number of the biopsies did not exhibit these features. In immunohistochemistry staining, T cells, B cells and macrophage subtypes counts were comparable between GPA, sarcoidosis and IIOD. Nonetheless cytokines IL-17, IL-23 and BAFF-receptor (BAFF-R), were found significantly more in GPA compared to sarcoidosis and IIOD. This suggests that these cytokines possibly have a role in the pathogenesis of GPA and may have diagnostic value.

Les techniques de communication évoluées actuelles mises en oeuvre au sein des ateliers, caractérisées par les réseaux locaux industriels et les outils de communication qu'intègrent les équipements, ne sont pas ou peu mises au service de l'interfaçage entre le système de gestion de production et les postes de travail de l'atelier. La mise en oeuvre de cette communication est rendue difficile du fait de l'hétérogénéité des équipements. La gestion de la fabrication au sein de l'atelier passe alors souvent par l'intermédiaire des opérateurs. Par conséquent, fiabilité de l'information et dynamique des échanges ne sont pas garantis. Les travaux présentés dans ce mémoire contribuent à définir une architecture de communication intégrante pour le pilotage et le suivi des procédés industriels en exploitant ces moyens de communication. Dans ce contexte, plusieurs aspects sont explorés. L'étude des systèmes de communication industriels nous amène à constater que la messagerie MMS (Manufacturing Message Specification) représente un langage de communication permettant de définir une architecture de communication intégrante au sein d'un système automatisé de production. L'aspect GPAO et divers travaux relevant du domaine des systèmes d'information en gestion de production nous permettent d'acquérir une vue générale de la gestion d'atelier, sous un aspect informationnel. Enfin, en considérant différentes méthodes de modélisation pour l'analyse des systèmes d'information, nous avons choisi d'utiliser la méthode orientée objet OMT (Object Modeling Technique) dans le cadre de nos travaux. En nous plaçant dans un contexte particulier, nous proposons une approche méthodologique pour l'intégration des activités de gestion de production au niveau des équipements de l'atelier. La démarche consiste à partir de modèles OMT décrivant un système de GPAO et de modèles décrivant un poste de travail d'un point de vue communication, de dériver vers une architecture de communication basée sur la messagerie MMS. Afin de valider notre approche, nous expérimentons la démarche en mettant en oeuvre une application de maquettage d'un poste de travail à commande numérique communicant avec un poste de GPAO, en utilisant MMS
The current advanced communication techniques implemented within workshop, characterized by industrial local area networks and communication tools integrated by equipment, are often not used for interfacing between production management system and workstations of workshop. The implementation of this communication is difficult because heterogeneity of equipment. Manufacturing management within the workshop is often then realized by intermediary of the operators. Reliability of information and dynamics of exchanges are therefore not guaranteed. The research presented in this work contributes to defining an integral communication architecture for control and monitoring of the industrial processes by using these communication tools. Ln this context, several points of view are explored. The study of the industrial communication systems leads us to note that the industrial messaging MMS (Manufacturing Message Specification) represents a communication language making it possible to define an integral communication architecture within an automated production system. CAMM (Computer Aided Manufacturing Management) point of view and different work in the area of the information systems in production management enable us to acquire a general view of the workshop management, under an informational aspect. Finally, by considering different modelling methods for the analysis of the information systems, we chose to use the object oriented method OMT (Object Modeling Technique) for our work. By setting us in a specifie context, we propose a methodological approach for the integration of the production management activities at the level of the equipment in the workshop. By starting from OMT model describing a CAMM system and model describing a workstation from a communication point of view, it consist to derive towards a communication architecture using the messaging MMS. In order to validate our approach, we experiment our method by realising a prototyping application of a numerical control workstation which communicates with a CAMM system by using MMS

Face à des problèmes complexes et évolutifs, l'informatisation de la fonction production d'une entreprise manufacturière est difficile à mettre en oeuvre. L'approche objet, utilisant l'objet comme un modèle de données, est une approche appropriée pour de tels problèmes, qui ne peuvent être abordés autrement que par une modélisation. L'objectif des travaux présentés dans ce mémoire de thèse est d'étudier et d'évaluer dans le cadre de la problématique de la gestion de production, l'approche objet, et compte tenu d'améliorations possibles, proposer une approche objet/objet dédiée à la fonction production d'une entreprise manufacturière.

Problèmes de la gestion de l'énergie d'une telle installation et instrumentation nécessaire. Cahier de charge de la chaufferie automatisée pour supprimer les relevés erronés; problème de fiabilité des capteurs notamment pour les mesures sur la fumée

Thesis (M.A.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Counseling and Personnel Services. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.