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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Contribution à la modélisation de l’absorption du cadmium par les racines du tournesol (Helianthus annuus L.) en relation avec l’architecture racinaire. / Contribution to the cadmium absorption modeling by sunflower roots (Helianthus annuus L.) in relation with root system architecture

Laporte, Marie-Aline 20 December 2013 (has links)
Le cadmium (Cd) est naturellement présent dans les sols qui sont aussi enrichis par l'activité humaine. Le Cd contamine les produits végétaux alimentaires car il est absorbé par les racines des plantes. Elément toxique pour les organismes vivants, les concentrations dans les produits consommés sont soumises aux règlementations pour l’alimentation humaine et animale. Il est donc nécessaire de comprendre le transfert sol-organe consommé du Cd, spécialement pour le tournesol (Helianthus annuus L.), notre plante modèle, pouvant accumuler plus de Cd que d’autre plantes cultivées. Ce travail a testé l'hypothèse que la quantité de Cd absorbée par le système racinaire du tournesol était liée à l'architecture de ce dernier. Nous avons caractérisé au niveau des racines individuelles une variation longitudinale de l’influx d'absorption du Cd2+ en lien avec le milieu de culture, l'ordre et l'âge des racines. Ces variations ont été attribuées à la dynamique de développement des barrières apoplasmiques (dépôts de cellulose lignine et subérine) qui limitent l'internalisation du Cd2+ dans le cytoplasme cellulaire. Par simulation, il a été montré que ces variations pouvaient théoriquement impacter l'absorption totale de Cd2+ en fonction de l'architecture racinaire en hydroponie mais beaucoup moins sur substrat solide (sable). En outre, une comparaison de 14 cultivars de tournesol cultivé en hydroponie a montré que la variabilité des teneurs en Cd dans les parties aériennes était plutôt liée à des différences d'absorption indépendantes de l'architecture racinaire et à des variations de répartition dans la plante. Les variations longitudinales d'absorption du Cd peuvent alors être considérées comme mineures face à des variations inter-cultivars dont l'origine reste à élucider. Dans une optique de modélisation du prélèvement total en conditions de sol, il serait alors possible de ne considérer qu’un influx moyen de Cd pour la totalité du système racinaire indépendamment de son architecture / Cadmium (Cd) is naturally occurring in soils that are also enriched by human activity. Cd contaminates food crops because of its absorption by plant roots. Because it is a toxic element for living organisms, its concentrations in food and feed plant products are subjected to regulatory limits. Therefore, it is necessary to understand the transfer of this metal from the soil to the edible plant part, especially for sunflower (Helianthus annuus L.), our model plant that can accumulate more Cd than other crop species. This study tested the hypothesis that the amount of Cd absorbed by sunflower was related to the root architecture. We characterized, at the individual roots level, a longitudinal variation of the influx of Cd2+ absorption in relation with the culture medium, the order and the age of roots. These variations were attributed to the development of apoplastic barriers (cellulose, lignin and suberin deposition) that restrict the absorption of Cd2+ into the cytosol. By simulation, it has been shown that these variations could theoritically impact the total absorption of Cd2+ in hydroponics depending on the root architecture while in solid substrate (sand) the impact was much more limited. Furthermore, a comparison of 14 sunflower cultivars showed that the variability in Cd concentrations in shoots was rather due to differences in absorption independent of root architecture and in variations in the root to shoot distribution. The longitudinal variation in the Cd root influx can then be considered of minor importance compared to the between cultivar variability in Cd uptake, the origin of which remains to be determined. In the perspective of modelling the total uptake of Cd in soil conditions, it could then be possible to assume a global mean influx of Cd independent of the root architecture
42

Prima facie status jako možné řešení hromadného přílivu uprchlíků / Prima Facie Status as a Possible Solution for Mass Influx of Refugees

Radová, Kateřina January 2018 (has links)
This thesis addresses the topic of mass influx of refugees and its possible solutions. It examines the concept of prima facie refugee status determination in group situations, which is plentifully used in states of the economic South as a solution to mass influx of refugees. Despite its ample use, it is not entirely clear what can be understood by it. A better way to tackle mass influxes of refugees is sought here in response to the European migration "crisis" which has shed light on the unpreparedness of the Common European Asylum System for a large scale influx. The prima facie refugee status determination is put here as an opposite to individualized refugee status determination, which is assumed by the western doctrine and practice to be the only possible way of determining refugee status under the 1951 Convention. Even though individualized refugee status determination may be an appropriate tool in times of relatively low number of refugees, as it has been the case for a long time at the European continent, it may be different in situations of mass influx of refugees. Such individualized refugee status determination is very costly and lengthy procedure and as such not very suitable for situation of mass influx of refugees. To answer the question of whether the prima facie refugee status...
43

Physiology of Potassium Nutrition in Cereals: Fluxes, Compartmentation, and Ionic Interactions

Szczerba, Mark 01 August 2008 (has links)
Potassium (K+) is an essential nutrient and the most abundant cation in plant cells. Plants possess two transport systems for K+ acquisition: a high-affinity system (HATS), operating at external K+ concentrations ([K+]ext) below 1 mM, and showing reduced transport activity in the presence of ammonium (NH4+); and, a low-affinity system (LATS), operating at [K+]ext above 1 mM, that is not affected by NH4+. K+ transport and compartmentation were investigated in barley (Hordeum vulgare L.) and rice (Oryza sativa L.) using the non-invasive technique of compartmental analysis by tracer efflux (CATE), to simultaneously determine unidirectional membrane fluxes, ion concentrations, and exchange characteristics in subcellular compartments. These studies revealed striking differences in unidirectional K+ fluxes between HATS and LATS. It was found that flux measurements, using traditional direct influx (DI) protocols, accurately represented HATS influx, but underestimated LATS influx by as much as seven-fold. In both barley and rice, LATS K+ fluxes were found to undergo rapid, futile cycling, with the ratio of efflux:influx 3 to 5 times greater, and the cytosolic exchange rate 2 to 3 times faster than under HATS. Based upon plasma-membrane electrical potential measurements, efflux was found to be active under LATS conditions. LATS-mediated conditions for K+ were found to provide relief from NH4+ toxicity in barley by immediately reducing NH4+ influx by more than 50%, and significantly reducing NH4+ futile cycling. Employing the K+ channel inhibitors cesium, lanthanum, and tetraethylammonium, NH4+ was shown to have both K+-sensitive and –insensitive influx pathways at high [NH4+]ext. Based on current models of flux energetics, the combined uptake of K+ and NH4+ was found to utilize 60% of root oxygen consumption. Barley and rice both showed signs of NH4+ toxicity at low [K+]ext, but rice recovered at much lower [K+]ext, suggesting a crucial role of K+ in the NH4+-tolerance of rice. These experiments address fundamental aspects of K+ fluxes, and help provide a physiological framework for future studies of K+ transport and mineral nutrition.
44

Physiology of Potassium Nutrition in Cereals: Fluxes, Compartmentation, and Ionic Interactions

Szczerba, Mark 01 August 2008 (has links)
Potassium (K+) is an essential nutrient and the most abundant cation in plant cells. Plants possess two transport systems for K+ acquisition: a high-affinity system (HATS), operating at external K+ concentrations ([K+]ext) below 1 mM, and showing reduced transport activity in the presence of ammonium (NH4+); and, a low-affinity system (LATS), operating at [K+]ext above 1 mM, that is not affected by NH4+. K+ transport and compartmentation were investigated in barley (Hordeum vulgare L.) and rice (Oryza sativa L.) using the non-invasive technique of compartmental analysis by tracer efflux (CATE), to simultaneously determine unidirectional membrane fluxes, ion concentrations, and exchange characteristics in subcellular compartments. These studies revealed striking differences in unidirectional K+ fluxes between HATS and LATS. It was found that flux measurements, using traditional direct influx (DI) protocols, accurately represented HATS influx, but underestimated LATS influx by as much as seven-fold. In both barley and rice, LATS K+ fluxes were found to undergo rapid, futile cycling, with the ratio of efflux:influx 3 to 5 times greater, and the cytosolic exchange rate 2 to 3 times faster than under HATS. Based upon plasma-membrane electrical potential measurements, efflux was found to be active under LATS conditions. LATS-mediated conditions for K+ were found to provide relief from NH4+ toxicity in barley by immediately reducing NH4+ influx by more than 50%, and significantly reducing NH4+ futile cycling. Employing the K+ channel inhibitors cesium, lanthanum, and tetraethylammonium, NH4+ was shown to have both K+-sensitive and –insensitive influx pathways at high [NH4+]ext. Based on current models of flux energetics, the combined uptake of K+ and NH4+ was found to utilize 60% of root oxygen consumption. Barley and rice both showed signs of NH4+ toxicity at low [K+]ext, but rice recovered at much lower [K+]ext, suggesting a crucial role of K+ in the NH4+-tolerance of rice. These experiments address fundamental aspects of K+ fluxes, and help provide a physiological framework for future studies of K+ transport and mineral nutrition.
45

Waste management in the Sebideng District Municipality : a strategy for improved service delivery / Khathutshelo Elias Masindi.

Masindi, Khathutshelo Elias January 2009 (has links)
Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.
46

Waste management in the Sebideng District Municipality : a strategy for improved service delivery / Khathutshelo Elias Masindi.

Masindi, Khathutshelo Elias January 2009 (has links)
Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.
47

The role of EGR-1 and calcium influx in the antitumor activity of anti-CD20 monoclonal antibodies / Le rôle d'EGR-1 et du flux calcique dans l'activité antitumorale des anticorps monoclonaux anti-CD20

Spasevska, Ivana 01 December 2017 (has links)
Les anticorps monoclonaux (AcM) anti-CD20 sont essentiels pour le traitement du lymphome non hodgkinien et de la leucémie lymphoïde chronique (LLC). Les AcM agissent soit en activant directement la signalisation apoptotique dans les cellules cibles, soit via le système immunitaire. Dans une étude préclinique, nous avons montré que le traitement avec AcM anti-CD20, rituximab et GA101, induit l'expression de la protéine early growth response 1 (EGR-1) (Dalle et al., 2011). EGR-1 est un facteur de transcription régulé par le calcium (Ca2+) et CD20 est impliqué dans la régulation du flux calcique transmembranaire. Nous avons donc étudié le rôle d'EGR-1 et du flux Ca2+ dans l'activité cytotoxique des AcM anti-CD20. Nous avons montré qu'EGR-1 est rapidement induit suite à l'exposition au rituximab et à GA101. La baisse de l'expression d'EGR-1 par shRNA a supprimé l'effet cytotoxique du GA101 à la fois in vitro et in vivo, indiquant qu'EGR-1 est requis pour la mort cellulaire médiée par CD20. De plus, la surexpression d'EGR-1 augmente la sensibilité au GA101 in vitro et in vivo. En outre, nos résultats indiquent que les AcM anti-CD20 induisent un flux Ca2+. Le blocage du flux Ca2+ par inhibiteurs de canaux calciques (ICC) a aboli l'induction d'EGR-1 ainsi que l'efficacité du GA101 in vivo et ex vivo dans des échantillons de LLC. Plus important, nos données indiquent que les patients recevant des ICC ont une moins bonne réponse au traitement par les AcM anti-CD20. En conclusion, nous avons identifié EGR-1 comme potentiel biomarqueur pour prédire la réponse à la thérapie anti-CD20 et démontré que les ICC ont un impact négatif sur l'efficacité des AcM anti-CD20 chez les patients / Anti-CD20 monoclonal antibodies (mAbs) are an essential component of the treatment of patients with non-Hodgkin's lymphoma and chronic lymphocytic leukemia (CLL). They mediate their antitumor effects by activating the immune system or by direct apoptotic signaling in target cells. In a previous preclinical study, we showed that treatment with anti-CD20 mAbs, rituximab and GA101, resulted in upregulated expression of early growth factor 1 (EGR-1) (Dalle et al. 2011). EGR-1 is a calcium (Ca2+) regulated transcription factor and CD20 is hypothesized to regulate transmembrane Ca2+ flux. Therefore, we aimed to assess the role of EGR-1 and Ca2+ flux in the cytotoxic activity of anti-CD20 mAbs. We have shown that EGR-1 expression is rapidly upregulated in CD20+ cells following rituximab and GA101 exposure. Decreasing EGR-1 expression by shRNA abolishes the direct cytotoxic effect of GA101 both in vitro and in vivo, indicating that EGR-1 is required for CD20-mediated cell death. Additionally, the overexpression of EGR-1 enhances the cytotoxic activity of GA101 both in vitro and in vivo. Furthermore, our results indicate that anti-CD20 mAbs induce calcium influx. Blocking the Ca2+ flux with calcium channel blockers (CCB) abolishes EGR-1 induction and impaires the GA101 efficacy in vivo and ex vivo in CLL blood samples. More importantly, our data indicate that patients receiving CCBs and anti-CD20 therapy have worst progression free survival and overall survival. In conclusion we have identified EGR-1 as a potential biomarker to predict response to anti-CD20 therapy. We demonstrated that co-treatement with CCBs negatively impacts the outcome of patients receiving anti-CD20 mAbs
48

Synthesis & biological evaluation of neuroprotective molecules with polycyclic scaffolds

Sharma, Rajan January 2017 (has links)
Doctor Pharmaceuticae - Dpharm / Among neurological disorders, many of the most devastating disorders are neurodegenerative. Modern research associates excitotoxicity to a variety of neuropathological conditions, suggesting that the neurodegenerative diseases with distinct etiologies may have excitotoxicity as a common pathway. Excitotoxicity occurs through over-stimulation of receptors for excitatory neurotransmitters like the N-methyl-D-aspartate (NMDA) receptors. Due to the relevance of NMDA receptors and excitotoxic processes, the antagonism or modulation of NMDA receptors is used as a therapeutic tool against neurodegenerative diseases. NMDA receptor activity can be modulated by S-nitrosylation and this modulation of NMDA receptor activity can be utilised in the development of neuroprotective drugs.
49

Eriodictiol: um flavonóide antagonista do receptor trpv1 com atividade antioxidante / Eriodictyol: A flavonoid antagonist of TRPV1 receptor with antioxidant activity

Rossato, Mateus Fortes 13 August 2010 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The transient receptor potential vanilloid 1 (TRPV1) is a calcium permeable channel responsible for the transduction and modulation of acute and chronic pain signaling, being a potential target for treatment of different pain disorders. In spite of that, AMG517, a TRPV1 antagonist, presents several clinical limitations, such as the development of severe hypertermia. The aim of this study was to investigate the possible interaction of the flavonoid eriodictyol with the TRPV1 receptor and its putative antinociceptive and hyperthermic effect. Eriodictyol was able to displace the [3H]-resiniferatoxin binding (IC50 = 47 (21 - 119) nM) and to inhibit the calcium influx mediated by capsaicin (IC50 = 44 (16 125) nM), suggesting that eriodictyol acts as a TRPV1 antagonist. Moreover, eriodictyol induces antinociception in the intraplantar capsaicin test, with maximal effect of 49±10 and 64±4% of inhibition for oral (ED50 = 2 (1-5) mg/kg) and intrathecal (ED50 = 2 (1-3) nmol/site) routes, respectively. Concomitantly, eriodictyol did not induce any alteration on body temperature or locomotor activity. Orally administered eriodictyol (4.5 mg/kg) prevented the nociception induced by intrathecal injection of capsaicin (72±6% of inhibition), the non-protein thiol loss and the 3-nitrotyronise (3-NT) formation induced by capsaicin in spinal cord. Eriodictyol (4.5 mg/kg, p.o.) also reduced the thermal hyperalgesia (100% of inhibition) and mechanical allodynia (62±9% of inhibition) elicited by complete Freund s adjuvant (CFA) paw injection. In conclusion, Eriodictyol acts as an antagonist of TRPV1 receptor and an antioxidant, inducing antinociception without some side effects and limitations expected for TRPV1 antagonists, as hyperthermia. / O receptor de potencial transiente vanilóide 1 (TRPV1) é um canal iônico permeável a cátions ativado por uma série de estímulos nocivos, como calor, acidificação e agentes irritantes como a capsaicina. Este receptor é responsável pela detecção e transmissão da dor aguda e crônica. Devido a isso, substâncias que modulem a atividade deste receptor apresentam um potencial clínico para o tratamento da dor. Assim, este trabalho objetiva a possível interação do flavonóide eriodictiol com o receptor TRPV1. Inicialmente, observamos que o eriodictiol foi capaz de deslocar o radioligante [3H]-resiniferatoxina, em ensaio de união específica, do receptor TRPV1 com uma concentração inibitória 50% (IC50) de 46.9 (20.70 - 118.9) nM. Ao mesmo tempo, o eriodictiol também inibiu o influxo de cálcio estimulado por capsaicina com IC50 de 44,4 (15,6 125,1) nM, sugerindo que este aja como um antagonista do receptor. Além disso, também observamos que o eriodictiol induz antinocicepção no teste da capsaicina intraplantar com efeito máximo de 49,0±10.5 e 63,9±4.0 % de inibição máxima para o tratamento oral e intratecal, respectivamente, e com uma dose efetiva 50% (DE50) de 2,4 (1,0 5,5) mg/kg 2,2 (1,6 2,9) nmol/site, respectivamente. Além disso, não observamos alterações na atividade locomotora ou temperatura corporal dos animais. A administração oral de eriodictiol também foi capaz de prevenir a nocicepção induzida por capsaicina intratecal (71,7±5,7 % de inibição). Ao mesmo tempo, o eriodictiol também aboliu a hiperalgesia térmica e reduziu a alodínia mecânica (62,4±9,2 %) induzidas por adjuvante completo de Freund. Da mesma forma, o eriodictiol também preveniu totalmente a diminuição de tiois não protéicos e formação de 3-nitrotirosina (3-NT) espinhais induzidas por capsaicina, ao passo que apresentou atividade antioxidante direta no texto de neutralização do radical ABTS. Em conclusão, nossos resultados mostram que o eriodictiol age como um antagonista do receptor TRPV1, com atividade antioxidante, induzindo antinocicepção sem os efeitos colaterais e limitações esperados para antagonistas do receptor TRPV1.
50

Développement synthétique d'une nouvelle librairie de 5-arylidène rhodanines sous irradiation micro-onde et d'analogues du SKF-96365 comportant des plateformes pyrazole, rhodanine et leurs évaluations biologiques / Synthetic development of a new library of 5-arylidene rhodanines under microwave irradiation and analogs of SKF-96365 containing pyrazole and rhodanine platforms, and biological assessments

Dago, Camille Déliko 17 December 2015 (has links)
Ce travail de thèse a eu pour but la synthèse de nouveaux composés hétérocycliques (rhodanines et pyrazoles) potentiellement actifs sur des protéines kinases, des lignées cellulaires tumorales, les influx SOCE (Store Operated Calcium Entry) et a ciblé principalement comme pathologies la malaria, la leishmaniose et le cancer. La première partie de cette étude a permis la synthèse d'une nouvelle famille de dérivés 5-arylidène rhodanines dissymétriques comportant un bras espaceur diaminé et ce par l'intermédiaire de la technologie micro-onde. Sur les 7 protéines kinases testées avec ces composés, CK1δ/ε et CDK5/p25 ont été inhibées spécifiquement avec des CI50 comprises entre 1,1 et 10 µM. L'activité anticancéreuse enregistrée est moyenne avec des CI50 variant de 8 à 23 µM. Les travaux réalisés au cours de la seconde partie de cette étude se sont appuyés sur le SKF-96365 comme modèle structural et ont permis d'accéder à 3 librairies inédites d'analogues comportant les plateformes pyrazole et rhodanine. L'activité pharmacologique visée ici était une modulation des influx SOCE et diverses variations structurales ont été effectuées en vue de réaliser une étude Relation Structure-Activité (RSA). Plusieurs analogues "pyrazoles" ont montré une activité supérieure à celle du SKF-96365 et de la GSK-7975A sur les influx SOCE de la lignée HEK-293. Les 2 composés montrant la meilleure activité (30f et 30h), sont également plus actifs que la Synta 66 aux faibles concentrations. Ces analogues ont également une activité sélective des canaux SOCE concernés car totalement inactifs sur l'ensemble des protéines kinases testées. Les CI50 les plus significatives pour l'activité anticancéreuse varient entre 3 et 8 µM. / This thesis work has been aimed the synthesis of new heterocyclic compounds (rhodanines and pyrazoles) potentially active on kinase proteins, tumor cell lines, SOCE impulses (Store Operated Calcium Entry) and has mainly targeted pathologies such as malaria, leishmaniasis and cancer. The first part of this study allowed the synthesis of a new family of 5-arylidene rhodanine derivatives asymmetric having a diamino spacer arm and via microwave technology. Of the 7 protein kinases tested with these compounds, CK1δ/ε and CDK5/p25 have been specifically inhibited with IC50 between 1.1 and 10 µM. The recorded anticancer activity is average with IC50 ranging from 8 to 23 µM. The work carried out during the second part of this study was based on SKF-96365 as structural model and provided access to 3 unpublished libraries of analogs containing pyrazole and rhodanine platforms. The desired pharmacological activity was SOCE modulating and various structural changes were made to undertake a study Structure-Activity Relationship (SAR). Several "pyrazole" analogs have shown a higher activity than SKF-96365 and GSK-7975A on SOCE of HEK-293 line. The two compounds showing the best activity (30f and 30h) are also more active than Synta 66 at low concentrations. These analogs are completely inactive on all protein kinases tested, indicating selectivity for SOCE channels concerned. The most significant IC50 for the anticancer activity vary between 3 and 8 µM.

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