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The Impact of NOD Reaction Kinetics on Treatment EfficiencyJones, Laura January 2007 (has links)
In situ chemical oxidation (ISCO) with permanganate is a remedial technology that has been prevalent over the last decade. Permanganate is injected into the subsurface to oxidized reduced organic contaminants with the intent of mineralizing the organics to innocuous compounds such as water, oxygen, and carbon dioxide. However, the demand for permanganate from the naturally occurring reduced components associated with aquifer materials inhibits the ability of permanganate to effectively oxidize the target contaminants. This demand for permanganate is referred to as the Natural Oxidant Demand (NOD) and results from the presence of naturally occurring reduced aquifer species such as inorganic species containing iron, manganese, or sulfur, and natural organic matter. Traditionally, NOD has been considered to be an instantaneous sink for permanganate that required satisfaction before permanganate could propagate through the subsurface. However, recent research has suggested that NOD is kinetically controlled and not instantaneous resulting in the effectiveness of ISCO systems to be underestimated using traditional approaches. The objectives of this research were to develop a comprehensive NOD kinetic model from existing laboratory data of several aquifer materials, and then to use this model to estimate the impact of NOD kinetics on treatment efficiency.
The NOD kinetic model primarily was developed using results of bench-scale experiments performed on four aquifer materials, measuring the reduction of permanganate and oxidizable materials. Data analysis indicated that there are two bulk reactions occurring: a fast reaction and a slow reaction. For both of these reactions a second-order rate law was deemed to be appropriate; first-order with respect to each reactant. The slow reaction was subject to passivation and the reaction rate coefficient decreased hyperbolically as manganese oxide reaction by-products precipitated on grains. The developed NOD kinetic model was incorporated into a 1-dimensional transport model and was used to successfully simulate the results of NOD column studies.
Experimental efforts were completed to validate the 1-dimensional reactive transport model with data for organic contamination. A column study was completed to characterize the oxidation of an isolated trichloroethylene residual source zone. The chloride breakthrough data were used to represent the rate of TCE oxidation and a bromide tracer test was used as a conservative tracer to determine the dispersivity and porosity of the column. Both the simulated bromide and chloride breakthrough curves fit the experimental data well using published and calculated transport and chemical parameters.
The impact of NOD kinetics on treatment efficiency was evaluated through numerical simulations of four common organic contaminants using two injection schemes: vertical well flushing and inject-and-leave. The treatment efficiency was defined as the fraction of supplied permanganate used to oxidize the organic compound. Two aquifer materials were simulated representing a wide range of NOD characteristics. The results indicated that despite a great difference in the ultimate NOD (order of 15) the treatment efficiency only varied by 0-7% between the materials. In general, the treatment efficiency of the contaminant increased as the solubility and the reaction rate coefficient increased.
For treatment of organic compounds with a low solubility and reaction rate coefficient, the fast and slow NOD reaction kinetics should both be characterized since both exert a strong demand for permanganate in both the vertical flushing and inject-and-leave schemes. For organic compounds having moderate solubility and reaction rate coefficient the NOD species that require kinetic characterization depends on the injection scheme used: for a vertical well flushing scheme only the fast NOD requires characterization, whereas for the inject-and-leave scheme both the fast and slow NOD require characterization. For treatment of organic compounds with high solubility and reaction rate coefficient only the fast NOD requires characterization since the organic and fast NOD are depleted at the same time and the slow NOD does not play a significant role in permanganate consumption while free phase organic and fast NOD remain.
Traditional modelling approaches were compared, using the vertical well flushing scheme, to compare the treatment efficiency with the NOD kinetic model to past methods. The model was used to simulate ISCO treatment when NOD kinetics were not included and when the ultimate NOD was assumed. The simulations with no NOD term overestimated the treatment efficiency whereas the simulations with the ultimate NOD model underestimated efficiency. These findings further stressed the importance of the NOD kinetics on treatment efficiency.
The kinetics of the NOD kinetics must be characterized to determine if ISCO is a viable, cost-effective treatment option when considering ISCO as a redial strategy. Mischaracterization of these reactions could result in either over or underestimation of the treatment efficiency and poor design of pilot and full-scale treatment systems.
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The Impact of NOD Reaction Kinetics on Treatment EfficiencyJones, Laura January 2007 (has links)
In situ chemical oxidation (ISCO) with permanganate is a remedial technology that has been prevalent over the last decade. Permanganate is injected into the subsurface to oxidized reduced organic contaminants with the intent of mineralizing the organics to innocuous compounds such as water, oxygen, and carbon dioxide. However, the demand for permanganate from the naturally occurring reduced components associated with aquifer materials inhibits the ability of permanganate to effectively oxidize the target contaminants. This demand for permanganate is referred to as the Natural Oxidant Demand (NOD) and results from the presence of naturally occurring reduced aquifer species such as inorganic species containing iron, manganese, or sulfur, and natural organic matter. Traditionally, NOD has been considered to be an instantaneous sink for permanganate that required satisfaction before permanganate could propagate through the subsurface. However, recent research has suggested that NOD is kinetically controlled and not instantaneous resulting in the effectiveness of ISCO systems to be underestimated using traditional approaches. The objectives of this research were to develop a comprehensive NOD kinetic model from existing laboratory data of several aquifer materials, and then to use this model to estimate the impact of NOD kinetics on treatment efficiency.
The NOD kinetic model primarily was developed using results of bench-scale experiments performed on four aquifer materials, measuring the reduction of permanganate and oxidizable materials. Data analysis indicated that there are two bulk reactions occurring: a fast reaction and a slow reaction. For both of these reactions a second-order rate law was deemed to be appropriate; first-order with respect to each reactant. The slow reaction was subject to passivation and the reaction rate coefficient decreased hyperbolically as manganese oxide reaction by-products precipitated on grains. The developed NOD kinetic model was incorporated into a 1-dimensional transport model and was used to successfully simulate the results of NOD column studies.
Experimental efforts were completed to validate the 1-dimensional reactive transport model with data for organic contamination. A column study was completed to characterize the oxidation of an isolated trichloroethylene residual source zone. The chloride breakthrough data were used to represent the rate of TCE oxidation and a bromide tracer test was used as a conservative tracer to determine the dispersivity and porosity of the column. Both the simulated bromide and chloride breakthrough curves fit the experimental data well using published and calculated transport and chemical parameters.
The impact of NOD kinetics on treatment efficiency was evaluated through numerical simulations of four common organic contaminants using two injection schemes: vertical well flushing and inject-and-leave. The treatment efficiency was defined as the fraction of supplied permanganate used to oxidize the organic compound. Two aquifer materials were simulated representing a wide range of NOD characteristics. The results indicated that despite a great difference in the ultimate NOD (order of 15) the treatment efficiency only varied by 0-7% between the materials. In general, the treatment efficiency of the contaminant increased as the solubility and the reaction rate coefficient increased.
For treatment of organic compounds with a low solubility and reaction rate coefficient, the fast and slow NOD reaction kinetics should both be characterized since both exert a strong demand for permanganate in both the vertical flushing and inject-and-leave schemes. For organic compounds having moderate solubility and reaction rate coefficient the NOD species that require kinetic characterization depends on the injection scheme used: for a vertical well flushing scheme only the fast NOD requires characterization, whereas for the inject-and-leave scheme both the fast and slow NOD require characterization. For treatment of organic compounds with high solubility and reaction rate coefficient only the fast NOD requires characterization since the organic and fast NOD are depleted at the same time and the slow NOD does not play a significant role in permanganate consumption while free phase organic and fast NOD remain.
Traditional modelling approaches were compared, using the vertical well flushing scheme, to compare the treatment efficiency with the NOD kinetic model to past methods. The model was used to simulate ISCO treatment when NOD kinetics were not included and when the ultimate NOD was assumed. The simulations with no NOD term overestimated the treatment efficiency whereas the simulations with the ultimate NOD model underestimated efficiency. These findings further stressed the importance of the NOD kinetics on treatment efficiency.
The kinetics of the NOD kinetics must be characterized to determine if ISCO is a viable, cost-effective treatment option when considering ISCO as a redial strategy. Mischaracterization of these reactions could result in either over or underestimation of the treatment efficiency and poor design of pilot and full-scale treatment systems.
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TETRA? : En uppsats om valet av nationellt kommunikationssystem för "Blåljusmyndigheterna" / TETRA? : A thesisabout the choice of a national communications system for "Public safety" authoritiesFalkenback, Fredrik, Numminen, Emil January 2001 (has links)
Problemformulering: Statskontoret har fått i uppdrag att upphandla ett nytt kommunikationssystem för landets Ambulans, Polis och Räddningstjänsten. Utredningar såsom SOU 1998: 143 har pekat på att TETRA skall väljas. Man kan dock diskutera valet av kommunikationssystem utifrån argumentet att det nya kommunikationssystemet skall skapa mervärde. Detta mervärde kan man tänka endast skapas vid krissituationer. Det är då som fokuset skiftar från kostnader till funktionalitet och de värden man kan spara. Frågan är bara hur ofta kriser och onormala händelser inträffar samt vilka andra påverkbara problem som finns. Sannolikheten att katastrofer inträffar är ofta mycket överdrivna av människan. Även olika typer av trånga sektioner kan begränsa en räddningsinsats. Syfte: Uppsatsens syfte är att undersöka om Ambulans, Polis och Räddningstjänst i Karlskrona/Ronneby kan bedriva sin verksamhet med ett UMTS system för kommunikation, utifrån ett funktionalitets perspektiv, istället för ett TETRA system. Metod: Teknisk jämförelse och en fallstudie hos Ambulans, Polis och Räddningstjänst. Slutsatser: Vi anser att den nyckelskillnad TETRA har, nod till nod, inte har den betydelsen, att UMTS inte skulle kunna ses som ett alternativ till TETRA. UMTS blir även en mer kostnadseffektiv lösning för samhället. / Fredrik Falkenback Folkparksvägen 11:33 372 38 Ronneby Tel: 0457-126 97 Mobil: 070-598 26 97 Emil Numminen Älgbacken 1 372 34 Ronneby Tel: 0457-100 16 Mobil: 070-985 91 19
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En diskursanalys om förskolebarns minnesfunktioner i relation till språkligt lärandeRupush, Lena January 2015 (has links)
Syftet med det här examensarbetet är att undersöka ett urval vetenskapliga artiklar om förskolebarns minnesfunktioner när de lär sig språk. Samtliga artiklar är från USA. Metoden är en diskursanalys av tolv vetenskapliga artiklar med förskolebarn som ingår i språkliga aktiviteter. Studien använder sig av en analysmetod som diskursteoretikerna Laclau och Mouffe förespråkar. Denna analysmetod är ekvivalenskedjan som nystar fram navet i de diskurser som finns i de olika artiklarna. Frågeställningen är vilka föreställningar om barns minnesfunktioner som finns i forskning om barns lärande och hur de kan tolkas som olika diskurser? Resultatet utföll i att det exponerades flera olika diskurser i artiklarna, dock med många likheter med varandra. Gemensamt för de olika diskurserna om hur barn minns och lär sig språk blev, att förskolebarns positiva minnesfunktioner främjar barns lärande, då navet för de flesta diskurser som kunde påträffas i det empiriska materialet var positivt laddade begrepp.
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Avaliação dos efeitos da administração do gangliosideo GM1 na modulação do diabetes mellitus autoimune e expressão de citocinas, Nerve Growth Factor e seu receptor TrkA em camundongos NOD (non obese diabetic) / Effects of GM1 administration on autoimmune diabetes modulation and cytokines expression, Nerve Growth Factor and TrkA receptor in NOD mice (non obese diabetic)Ferro, Karla Priscila Vieira, 1981- 02 December 2007 (has links)
Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T16:26:14Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007 / Resumo: A linhagem de camundongos NOD (non obese diabetic) desenvolve espontaneamente diabetes mellitus tipo 1 (DM-1) com marcante similaridade ao observado em humanos, que se estabelece entre 12ª e 24ª semana de vida, com presença de autoanticorpos específicos contra antígenos pancreáticos. Grande parte das células encontradas são linfócitos T CD4+ e T CD8+ e, embora células NK, linfócitos B, células dendríticas e macrófagos também possam ser identificados nas lesões, o desenvolvimento da doença é primariamente dependente de linfócitos T CD4+ e CD8+ auto-reativos. A diferenciação e funcionamento de células ß são regulados por uma variedade de hormônios e fatores de crescimento, incluindo Nerve Growth Factor (NGF). Sabe-se que células-ß pancreáticas expressam receptores funcionais para NGF e esta neurotrofina induz modificações morfológicas e fisiológicas, incluindo estimulação da secreção de insulina. Estudos de terapias para o DM-1 baseadas na intervenção sobre o sistema imunológico revelam que estas podem ser estratégias promissoras para impedir a instalação e/ou evolução da doença. Neste contexto, investigamos os efeitos da administração de GM1 sobre a incidência do DM-1 e insulite em camundongos NOD, expressão de citocinas, NGF e seu receptor de alta afinidade TrkA. Nossos resultados sugerem que administração de GM1 na dose de 100mg/kg/dia em camundongos NOD fêmeas a partir da 4ª semana de vida é capaz de diminuir o índice de infiltrado inflamatório e conseqüentemente a expressão do diabetes, modulando negativamente o infiltrado inflamatório bem como a expressão gênica de citocinas pró-inflamatórias (IL-12, IFN-?, TNF-a e IL-1ß), além de aumentar a expressão gênica e protéica de NGF e TrkA, que pode atuar como regulador de sobrevivência da célula ß de maneira a inibir a apoptose desta célula / Abstract: The strain of NOD mice (non obese diabetic) spontaneously develops diabetes mellitus type 1 (DM-1) with strong similarity to the observed in humans. In this model, the diabetes manifestation occurs among 12th and 24th weeks of life, with presence of pancreas-specific autoantibodies. Great part of the cells are CD4+ and CD8+T cells, and even so NK cells, lymphocytes B, dendritics cells and macrophages also can be identified in the injuries, the development of the disease is essentially dependent of autoreactive CD4+ and CD8+ T cells. It was demonstrated that ? - pancreatic cells express NGF functional receptors and that this neurotrophin induces morphological and physiological modifications in pancreatic ? cells, including stimulation in insulin secretion. The inquiries of therapies for the DM-1 based on the intervention on the immune system disclose that these can be promising strategies to hinder the installation and/or evolution of the disease. In this context, we investigate the effect of GM1 administration on the incidence of DM-1 and insulitis in NOD mice, cytokines expression, NGF and its high affinity receptor TrkA. Our results suggest that administration of GM1 in the dose of 100mg/kg/dia in female NOD mice from 4ª week of life are capable to reduce the index of inflammatory infiltrated and consequently the expression of diabetes, down-modulating the inflammatory infiltrated as well as the gene expression of pro-inflammatory cytokines (IL-12, IFN-?, TNF-? and IL-1?), besides increasing the gene and protein expression of NGF and TrkA, that can act as regulating of ß cell - survival in way to inhibit apoptosis of this cell / Mestrado / Ciencias Basicas / Mestre em Clinica Medica
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Estudo do efeito do gangliosideo GM1 sobre os nervos perifericos do camundongo NOD (Non Obese Diabetic) / Effect of GM1 ganglioside in the sciatic nerves of the NOD (non obse diabetic)Rossi, Thiago 31 August 2007 (has links)
Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T03:27:40Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007 / Resumo: A linhagem de camundongos NOD (non obese diabetic) desenvolve espontaneamente diabetes mellitus tipo 1 (DM-1) com marcante similaridade ao observado em humanos, que se estabelece entre 12ª e 24ª semana de vida. Os gangliosideos são glicoesfingolipídeos de membrana que contém ácido siálico em sua composição e estão presentes na maioria das células dos vertebrados sendo particularmente abundantes no sistema nervoso. Gangliosídeos exógenos são capazes de acelerar a regeneração de nervos periféricos danificados, porém tem sido relacionados com síndromes neuropáticas periféricas como a síndrome de Guilláin Barret onde os pacientes apresentam anticorpos anti-gangliosídeos especificamente contra o gangliosídeo GM1. Entretanto os mecanismos ainda permanecem controversos. Nossos resultados sugerem que administração de GM1 na dose de 100mg/kg/dia em camundongos NOD e Balb/C fêmeas a partir da 4ª semana de vida não é capaz de provocar neuropatia clínica e que animais diabéticos apresentaram maior imunoreatividade para GM1 nos nervos periféricos com presença de marcação para NGF somente em camundongos Balb/C. Os animais diabéticos tratados com GM1 demonstraram queda na atividade nervosa, em contraste os camundongos Balb/C tratados com GM1 apresentaram aumento significativo na atividade nervosa / Abstract: The strain of NOD mice (non obese diabetic) spontaneously develops diabetes mellitus type 1 (DM-1) similarity to the observed in humans. In this model, the diabetes manifestation occurs between 12th and 24th weeks of life, with presence of pancreas-specific autoantibodies. The gangliosides are glycosphingolipids of membrane that contains sialic acid in their composition and are present in the majority of cells from vertebrates and are particularly abundant in the nervous system. Exogenous gangliosides are capable to increase regeneration in damaged peripheral nerves. However, the gangliosides are related with peripheral neuropathics syndromes as the syndrome of Guilláin Barret in which the patients specifically present antibodies against gangliosides GM1, however these mechanisms still remain controversial. Our results suggest that administration of GM1 in the dose of 100mg/kg/day in female NOD and Balb/C mice at the 4th week of life is not capable to provoke clinical peripheral neuropathy and that diabetic animals present major immunoreactivity for GM1 in peripheral nerves with the presence of immunoreactivity to NGF only in Balb/C mice. Diabetic animals treated with GM1 showed lower nervous activity when compared to Balb/C mice, which presented significant increase / Mestrado / Ciencia Basica / Mestre em Clinica Medica
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Modulação da expressão de fatores de regeneração/crescimento de ilhotas pancreáticas e tecido acinar pancreático em camundongos NOD (non-obese diabetic) tratados com gangliosídeos : Modulation of regeneration/growth factors expression in pancreatic exocrine and endocrine tissue of NOD (non-obese diabetic) mice treated with gangliosides / Modulation of regeneration/growth factors expression in pancreatic exocrine and endocrine tissue of NOD (non-obese diabetic) mice treated with gangliosidesSilva, Luís Guilherme Stivanin, 1985- 21 August 2018 (has links)
Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T01:15:46Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012 / Resumo: Empregando as linhagens de camundongos NOD (non-obese diabetic) de desenvolvimento espontâneo do diabetes mellitus tipo 1 e BALB/c como linhagem controle, administrou-se exogenamente gangliosídeo GM1, mistura de gangliosídeos (GGs) (GM1 21%, GD1a 40%, GD1b 16%, GT1b 19%) e solução salina (0,9% NaCl) estéril da 4ª à 28ª semana de vida. Os efeitos da administração dos gangliosídeos sobre a frequência da manifestação do diabetes, índice de insulite, imunofenotipificação e atividade apoptótica de células presentes em ilhotas pancreáticas de NOD foram verificados por meio de análise glicêmica semanal, técnica colorimétrica com Eosina-Hematoxilina, imunofluorescência e TUNEL. A expressão gênica e os níveis séricos de insulina, além das expressões celular protéica e gênica dos fatores de regeneração GLP-1, PDX-1 e Ngn3 nos tecidos pancreáticos de BALB/c e NOD foram analisados por meio de ELISA, imunofluorescência e RT-PCR em tempo real. Após 28 semanas de tratamento, pôde-se verificar que os animais tratados com GM1 reduziram o diabetes de 70% observado nos animais controle salina, para 38%. Os animais tratados com GGs não apresentaram diabetes. O índice de insulite estava diminuído nos animais tratados com GM1 (p=0.09), GGs (p=0.004) e salina não-diabético (ND) (p=0.02) em relação ao grupo salina diabético (DM). O número de células apoptóticas nas ilhotas dos grupos NOD salina ND e NOD DM estava aumentado em relação aos grupos tratados com GM1 e GGs. Os níveis de insulina sérica estavam aumentados nos grupos BALB/c GGs (p=0.01) e BALB/c GM1 (p=0.03) em relação ao grupo BALB/c salina e nos grupos NOD GGs (p=0.008) e NOD salina ND (p=0.01) em relação ao grupo diabético. Por outro lado, os níveis de expressão gênica de insulina no grupo NOD GM1 (p=0.02) estavam aumentados em relação ao grupo salina. Quanto às expressões protéicas de GLP-1, PDX-1 e Ngn3, em ilhotas pancreáticas e tecido acinar, verificamos aumento no grupo NOD tratado com GGs. O conjunto dos resultados demonstra que os gangliosídeos diminuem a manifestação do diabetes espontâneo na linhagem NOD. Hipotetizamos que uma das propriedades dos gangliosídeos estudados é a de estimular a expressão de GLP-1, PDX-1 e Ngn3 em células do tecido acinar e em células da linhagem endócrina nas ilhotas pancreáticas dos animais tratados seja NOD ou BALB/c. Desta forma abrem-se novas frentes de estudos das propriedades antiinflamatórias e possivelmente regenerativas dos gangliosídeos / Abstract: In the present study we evaluate the properties of GM1 and GGs (21% GM1, 40% GD1a 16% GD1b, 19%GT1b) in NOD (non-obese diabetic) mice and BALB/c as a control lineage. Animals of both lineages were treated with GM1, GGs or saline from 4th to the 28th weeks of life. The ganglioside-treated NOD mice demonstrated a decrease in insulitis compared with saline-treated mice: 70% of saline control animals, 38% of GM1 group and 0% of GGs group. GLP-1 gene expression was increased in GM1-treated BALB/c and in GGs-treated NOD groups in comparison to the saline groups. Insulin gene expression was increased only in the GM1-treated NOD group. Serum insulin levels were increased in ganglioside-treated BALB/c and NOD groups. In the islets, the cell co-labeling of Insulin/GLP1 and somatostatin/GLP1 was increased in NOD and BALB/c gangliosides-treated mice compared to saline-treated mice. PDX-1 and Ngn3 protein expression were increased in pancreatic islets and exocrine tissues of GGs treated NOD mice in comparison to the saline treated group. Results suggest that gangliosides have modulatory properties, decreasing the insulitis score, maintaining of insulin levels, increasing GLP-1 protein expression in ? and ? pancreatic cells and retarding diabetes onset in NOD mice. Similarly to observation in neural tissue, the gangliosides studied could contribute to islets survival. We hypothesize that ganglioside play a role stimulating growth factor expression GLP-1, PDX-1 and Ngn3 in the cells from acinar tissue and islets cells / Mestrado / Clinica Medica / Mestre em Clinica Medica
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Le rôle des cytokinines dans la mise en place de l’architecture racinaire des légumineuses / Role of cytokinins in legume root architectureBoivin, Stéphane 10 February 2016 (has links)
En réponse à une carence en azote dans le sol, les légumineuses sont capables d’interagir avec une bactérie du sol, Rhizobium, pour former un nouvel organe spécifique: la nodosité fixatrice d’azote atmosphérique. Chez la plante modèle des légumineuses Medicago truncatula, le récepteur aux cytokinines MtCRE1 est essentiel pour cette interaction symbiotique. Cependant, trois autres récepteurs aux cytokinines CHASE Histidine Kinase (CHK) existent chez M. truncatula. Les quatre CHKs ont des profils d’expression redondants dans les étapes précoces de la formation des nodosités, et plus divergeant dans les nodosités différenciées, même si MtCRE1 est le plus exprimé. Le locus génomique du plus proche homologue de MtCRE1 chez la plante non-symbiotique Arabidopsis, AHK4, complémente l’initiation des nodosités, mais seulement partiellement les phénotypes de croissance des nodosités et de fixation d’azote. Parmi les Régulateurs de Réponse de type B agissant en aval des CHKs, RRB3 a été sélectionné pour réaliser une stratégie de délétion de domaines protéiques, révélant son rôle positif dans la nodulation. Des données transcriptomiques indiquant une régulation de MtCRE1 dans l’épiderme en réponse à un « traitement symiotique », des approches fonctionnelles ont été réalisées et ont permis d’identifier un rôle négatif des cytokinines et de la voie MtCRE1 dans l’épiderme en réponse à ces « conditions symbiotiques ».En parallèle de ces travaux, des mutants des CHKs chez le pois ont été générés. A terme, ces recherches permettront de sélectionner un génotype tolérant à différents stress biotiques et abiotiques sans affecter les symbioses bénéfiques chez une espèce d’intérêt agronomique. / Legume plants adapt to low nitrogen by developing an endosymbiosis with nitrogen-fixing soil bacteria to form a new specific organ: the nitrogen-fixing nodule. In the Medicago truncatula model legume, the MtCRE1 cytokinin receptor is essential for this symbiotic interaction. As three other CHASE Histidine Kinase (CHK) cytokinin receptors exist in M. truncatula, we determined their potential contribution to this symbiotic interaction. The four CHKs have extensive redundant expression patterns at early nodulation stages but diverge in differentiated nodules, even though MtCRE1 has the strongest expression. Interestingly, a genomic locus of the MtCRE1 homolog from the aposymbiotic Arabidopsis plant, AHK4, rescues noduleinitiation, but only partially the nodule growth phenotype, and not the nitrogen fixation capacity. Among type-B Response Regulators acting downstream of CHKs, RRB3 has been selected to perform protein deletions, revealing a positive role RRB3 in nodulation. Transcriptomic data indicating an epidermis MtCRE1 regulation during a « symbiotic traitment », functional approaches showed a negative role of cytokinins and MtCRE1 pathway in epidermis in response to « symbiotic conditions ». chk mutants have been generated in Pisum sativum. Ultimately, the aim of these researches is to set the bases to select in legume species of agronomic interest a genotype tolerant to biotic and abiotic stresses without affecting beneficial symbioses.
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Metab-Immune analysis of the non-obese diabetic mouseBanday, Viqar January 2016 (has links)
Type 1A diabetes mellitus or T1D is a chronic disease characterized by T cell mediated destruction of the insulin producing β cells in the islets of Langerhans. The classical symptoms include high glucose levels in urine and blood, polyuria, and polydipsia. Complications associated with T1D include blindness, amputations, and end-stage renal disease, and premature death. The non-obese diabetic (NOD) mouse, first described in 1980, is widely used as a model organism for T1D. T1D disease in the NOD mouse shares a number of similarities to human T1D including dependence on genetic and environmental factors. More than 30 disease associated gene regions or loci (termed insulin dependent diabetes, or Idd, loci) have been associated with T1D development in NOD. For some of these Idds, the corresponding region in human has been linked to the development of T1D in human. T1D, both in humans and mice, is recognized as a T cell mediated disease. However, many studies have shown the importance of both the metabolome and the immune system in the pathogenesis of the disease. Appearance of autoantibodies in the serum of patients is the first sign of pathogenesis. However, molecular and cellular events precede the immune attack on the β-cell immunity. It has been shown that patients who developed T1D have an altered metabolome prior to the appearance of autoantibodies. Although much is known about the pathogenesis of T1D, the contribution of the environment/immune factors triggering the disease is still to be revealed. In the present study both metabolic and immune deviations observed in the NOD mouse was analyzed. Serum metabolome analysis of the NOD mouse revealed striking resemblance to the human metabolic profile, with many metabolites in the TCA cycle significantly different from the non-diabetic control B6 mice. In addition, an increased level of glutamic acid was of the most distinguishing metabolite. A detailed bioinformatics analysis revealed various genes/enzymes to be present in the Idd regions. Compared to B6 mice, many of the genes correlated to the metabolic pathways, showed single nucleotide polymorphism (SNP), which can eventually affect the functionality of the protein. A genetic analysis of the increased glutamic acid revealed several Idd regions to be involved in this phenotype. The regions mapped in the genetic analysis harbor important enzymes and transporters related to glutamic acid. In-vitro islet culture with glutamic acid led to increased beta cell death indicating a toxic role of glutamic acid specifically towards insulin producing beta cells. In the analysis of the immune system, B cells from NOD mice, which are known to express high levels of TACI, were stimulated with APRIL, a TACI ligand. This resulted in enhanced plasma cell differentiation accompanied with increased class switching and IgG production. NOD mice have previously been shown to react vigorously to T-dependent antigens upon immunization. In this study we confirmed this as NOD mice showed an enhanced and prolonged immune response to hen egg lysozyme. Thus, serum IgG levels were significantly increased in the NOD mice and were predominantly of the IgG1 subtype. Immunofluorescence analysis revealed increased number of germinal centers in the NOD mice. Transfer of purified B and T cells from NOD to an immune deficient mouse could reproduce the original phenotype as seen in the NOD mice. Collectively, this thesis has analyzed the metabolomics and immune deviations observed in the NOD mice.
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Role of cytokines in the pathogenesis of type 1 diabetesHussain, Munther Jaffar January 1996 (has links)
T lymphocytes and macrophages appear to play an important role in mediating ß-cell damage and causing Type 1 diabetes. Both activated T cells and macrophages operate and interact through the release of soluble factors called cytokines, which influence the type and magnitude of immune responses. It has been suggested that cytokines such as TNF-α and IL-1α can damage the N-cell directly. In Type 1 diabetes, cytokines are likely to have a critical role in individuals whose immune system is unbalanced allowing the emergence of self-destructive processes. To investigate this possibility, sensitive assays to detect a range of cytokines of potential relevance to the immune pathogenesis of diabetes were establised. Using these, serum levels of IL-1α, IL-1N, TNF-α and IL-6 (macrophage-derived cytokines), IFN-γ and IL-2 (T helper 1 cytokine profile) and IL-4 and IL-10 (T helper 2 profile) have been measured in patients with Type 1 diabetes of different disease duration. Increased levels of TNF-α, IL-1α, IL-2 and IFN-γ were found in recently diagnosed patients with Type 1 diabetes when compared with both disease and metabolic control subjects and with normal controls. The presence of this profile of cytokines implies activation of the TH1 subset of helper cells near to diagnosis of Type 1 diabetes
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