Einleitung: L-Carnitin spielt eine zentrale Rolle im Energiestoffwechsel. Da dieser in der Frühlaktation bei Hochleistungskühen besonders beansprucht und z.T. überlastet wird, ergibt sich die Frage, ob durch L-Carnitinsupplementation ein stabilerer Stoffwechsel und damit bessere Leistungen erreicht werden können. Zielstellung: Es wurde geprüft, ob bei Hochleistungskühen mit einer mittleren Milchleistung von 12000 kg/Jahr die orale Supplementation von L Carnitin im peripartalem Zeitraum bei zwei verschiedenen Applikationszeiträumen Stoffwechsel-, Leistungs- und Gesundheitsverbesserung erbringt. Versuchsanordnung: Aus einer Gesamtherde von 322 Kühen wurden 81 Tiere randomisiert auf vier Gruppen aufgeteilt. Zwei dieser Gruppen erhielten L-Carnitin (Supplementationsgruppen) und die anderen zwei Gruppen stellten die Kontrollgruppen (KG 1 n = 14/ KG 2 n = 11) dar. Von den supplementierten Gruppen erhielt Car. 1 (n = 26) von 3 Wochen (Wo.) ante partum (a.p.) bis zur Kalbung über das Futter täglich 5g L Carnitin (Carnipas®). Post partum bekamen die Tiere 1g L Carnitin von der Kalbung bis vier Wo. p.p. Parallel wurden einer zweiten supplementierten Gruppe, Car. 2 (n = 30), täglich 5g L Carnitin 3 Wochen a.p. bis zur Kalbung verabreicht. Klinische und Blutkontrollen erfolgten 28 Tage (d) a.p., drei d p.p, 28 d p.p. sowie 56 d p.p. Es wurden das Gesamtcarnitin (GC, n = 5), das freie Carnitin (FC, n = 5), Carnitinester (CE, n = 5), FFS, BHB, Bilirubin, Glucose, Cholesterol, Harnstoff, TTP, Albumin, CK, AST, Pi, Ca, Fe bei allen Tieren analysiert. Zusätzlich erfolgte die Erfassung der Laktationsleistung, der Milchinhaltsstoffe, der Rastzeit (RZ), der Zwischentragezeit (ZTZ) und der Morbidität. Ergebnisse: Das GC, FC und die CE besitzen in den supplementierten Gruppen Car 1 drei d p.p. höhere Konzentrationen als die Kontrollgruppen, die bei Car. 2 (p < 0,05) im GC und FC auch im weiteren Verlauf beobachtet wurden. Ein deutlicher Konzentrationsabfall aller L-Carnitinfraktionen vier Wo. p.p. wurde in den supplementierten Gruppen beobachtet. In den Kontrollgruppen stiegen sie zur gleichen Zeit nicht einheitlich an. Acht Wochen p.p. sanken die L-Carnitinkonzentrationen im Blut sowohl in den Kontrollgruppen, als auch in der supplementierten Gruppen weiter ab. In allen Gruppen stiegen drei d p.p. die FFS-Konzentrationen an (p < 0,05), das BHB auch in den supplementierten Gruppen, die Glucose- und Cholesterolkonzentration fielen ab (p < 0,05). Vier und 8 Wo. p.p. ließen sich ein Abfallen der FFS- (p < 0,05) und der BHB-Konzentrationen (p < 0,05) erkennen. Die Cholesterol- (p < 0,05) und verzögert auch die Glucosekonzentration stiegen an. Drei d p.p. stiegen die Bilirubinkonzentration (p < 0,05) und die AST-Aktivität (p < 0,05) an, dem ein ebensolcher Abfall (p < 0,05) folgte. Präpartal trat in der supplementierten Gruppen Car. 2 eine höhere Bilirubinkonzentration als in der Kontrollgruppe (p < 0,05) auf, was bei den AST-Aktivitäten zwischen den supplementierten Gruppen postpartal (p < 0,05) der Fall war. Drei d p.p waren niedrigere Konzentrationen des Proteins (p < 0,05), des Albumins (p < 0,05) in Car. 2 und in der Kontrollgruppe sowie des Harnstoffs (p < 0,05) in den Kontrollgruppen zu beobachten. Die CK-Aktivität nahm drei d p.p. zu (p < 0,05), um vier Wo. p.p. wieder abzufallen (p < 0,05). Gleichzeitig war einen Anstieg des Proteins (p < 0,05) und des Albumins in den Kontrollgruppen (p < 0,05), verzögert auch in den supplementierten Gruppen (p < 0,05), messbar. In allen Gruppen waren drei d p.p. niedrigere Ca- (p < 0,05), Fe- (p < 0,05) und Pi- Konzentrationen (p < 0,05) auffällig, die später wieder anstiegen. Im Verlauf war die Ca-Konzentration bei Car. 2 gegenüber der Kontrollgruppe höher (p < 0,05). Die Leistungsparameter differierten weder bei den Milchleistungs-, noch bei den Fruchtbarkeitskennzahlen gesichert. Bezüglich der Morbidität war auffällig, dass das GC und FC bei gesunden Kühen a.p. gegenüber den im Laktationsverlauf erkrankten gesichert höher war (p < 0,05). Schlussfolgerungen: Orale L Carnitinapplikation bei Kühen mit hohem Milchleistungsniveau erbrachte keine Stoffwechsel-, Leistungs- und Morbiditätsunterschiede gegenüber den Kontrollgruppen. Die Ergebnisse entsprechen aber der Hypothese einer gesteigerten ß-Oxidation durch die Carnitinsupplementation mit erhöhten BHB-Konzentrationen als Folge. Post partum gesunde Kühe hatten a.p. signifikant höhere L-Carnitinkonzentrationen als kranke.

No description available.

Aging can be described as an extremely complex occurrence from which no organism can be excluded. Intrinsic and extrinsic aging make out the two components of skin aging and they differ on the macromolecular level while sharing specific molecular characteristics which include elevated levels of reactive oxygen species (ROS) and matrix metalloproteinase (MMP) while collagen synthesis decreases. The skin functions as a protective barrier against the harsh environment and is essential for regulating body temperature. The stratum corneum (SC) is responsible for the main resistance to the penetration of most compounds; nevertheless the skin represents as an appropriate target for delivery. The target site for anti-aging treatment includes the epidermal and dermal layers of the skin. Calendula oil and L-carnitine L-tartrate was utilised as the cosmeceutical actives as they can be classified as a mixed category of compounds/products that lie between cosmetics and drugs. Both show excellent properties which can prove valuable during anti-aging treatment, whether it is due to the scavenging of ROS (calendula oil), moisturising effects (calendula oil and L-carnitine L-tartrate) or the improvement of the skin turnover rate (L-carnitine L-tartrate). The Pheroid™ delivery system can enhance the absorption of a selection of active ingredients. The aim of this study was to determine whether the Pheroid™ delivery system will enhance the flux and/or delivery of the named actives to the target site by performing Franz cell diffusion studies over an 8 h period, followed by tape stripping experiments. The Pheroid™ results of the actives were compared to the results obtained when 1 00 % calendula oil was applied and the L-carnitine L-tartrate was dissolved in phosphate buffer solution (PBS), respectively. In the case of calendula oil only a qualitative gas chromatography mass spectrometry (GC/MS) method could be employed. No calendula oil was observed to permeate through the skin, but linoleic acid (marker compound) was present in the epidermis and dermis layers. Components in the Pheroid™ delivery system hampered the results as the marker compound identified is a fundamental component of the Pheroid™, making it difficult to determine whether or not the Pheroid™ delivery system enhanced calendula oil's penetration. The aqueous solubility and log D partition coefficient of L-carnitine L-tartrate was determined. Inspection of the log D value of -1.35 indicated that the compound is unfavourable to penetrate the skin, whereas the aqueous solubility of 16.63 mg/ml in PBS at a temperature of 32º C indicated favourable penetration. During the Franz cell diffusion and tape stripping studies it was determined by liquid chromatography mass spectrometry (LC/MS) that carnitine may be inherent to human skin. Pheroid™ enhanced the flux (average of 0.0361 µg/cm2.h, median of 0.0393 µg/cm2.h) of the L-carnitine L-tartrate when compared to PBS (average of 0.0180 µg/cm2.h, median of 0.0142 µg/cm2.h ) for the time interval of 2 -8 h. The PBS was more effective in delivering the active to the target site (0.270 µg/ml in the epidermis and 2.403 µg/ml in the dermis) than Pheroid™ (0.111 µg/ml and 1.641 µg/ml in the epidermis and dermis respectively). Confocal laser scanning microscopy (CLSM) confirmed the entrapment of L-carnitine L-tartrate in the Pheroid™ vesicle, while in the case of calendula oil it was impossible to differentiate between the oil and the Pheroid™ components. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

Aging can be described as an extremely complex occurrence from which no organism can be excluded. Intrinsic and extrinsic aging make out the two components of skin aging and they differ on the macromolecular level while sharing specific molecular characteristics which include elevated levels of reactive oxygen species (ROS) and matrix metalloproteinase (MMP) while collagen synthesis decreases. The skin functions as a protective barrier against the harsh environment and is essential for regulating body temperature. The stratum corneum (SC) is responsible for the main resistance to the penetration of most compounds; nevertheless the skin represents as an appropriate target for delivery. The target site for anti-aging treatment includes the epidermal and dermal layers of the skin. Calendula oil and L-carnitine L-tartrate was utilised as the cosmeceutical actives as they can be classified as a mixed category of compounds/products that lie between cosmetics and drugs. Both show excellent properties which can prove valuable during anti-aging treatment, whether it is due to the scavenging of ROS (calendula oil), moisturising effects (calendula oil and L-carnitine L-tartrate) or the improvement of the skin turnover rate (L-carnitine L-tartrate). The Pheroid™ delivery system can enhance the absorption of a selection of active ingredients. The aim of this study was to determine whether the Pheroid™ delivery system will enhance the flux and/or delivery of the named actives to the target site by performing Franz cell diffusion studies over an 8 h period, followed by tape stripping experiments. The Pheroid™ results of the actives were compared to the results obtained when 1 00 % calendula oil was applied and the L-carnitine L-tartrate was dissolved in phosphate buffer solution (PBS), respectively. In the case of calendula oil only a qualitative gas chromatography mass spectrometry (GC/MS) method could be employed. No calendula oil was observed to permeate through the skin, but linoleic acid (marker compound) was present in the epidermis and dermis layers. Components in the Pheroid™ delivery system hampered the results as the marker compound identified is a fundamental component of the Pheroid™, making it difficult to determine whether or not the Pheroid™ delivery system enhanced calendula oil's penetration. The aqueous solubility and log D partition coefficient of L-carnitine L-tartrate was determined. Inspection of the log D value of -1.35 indicated that the compound is unfavourable to penetrate the skin, whereas the aqueous solubility of 16.63 mg/ml in PBS at a temperature of 32º C indicated favourable penetration. During the Franz cell diffusion and tape stripping studies it was determined by liquid chromatography mass spectrometry (LC/MS) that carnitine may be inherent to human skin. Pheroid™ enhanced the flux (average of 0.0361 µg/cm2.h, median of 0.0393 µg/cm2.h) of the L-carnitine L-tartrate when compared to PBS (average of 0.0180 µg/cm2.h, median of 0.0142 µg/cm2.h ) for the time interval of 2 -8 h. The PBS was more effective in delivering the active to the target site (0.270 µg/ml in the epidermis and 2.403 µg/ml in the dermis) than Pheroid™ (0.111 µg/ml and 1.641 µg/ml in the epidermis and dermis respectively). Confocal laser scanning microscopy (CLSM) confirmed the entrapment of L-carnitine L-tartrate in the Pheroid™ vesicle, while in the case of calendula oil it was impossible to differentiate between the oil and the Pheroid™ components. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

Introdução: A acidemia 3-hidroxi-3-metilglutárica é causada pela deficiência da 3-hidroxi-3-metil-glutaril-CoA-liase, uma enzima do metabolismo da leucina, levando ao acúmulo, especialmente, do ácido 3-hidroxi-3-metilglutárico nos tecidos. Estudos sugerem que o estresse oxidativo pode contribuir para os danos neurológicos observados em algumas acidúrias orgânicas. Objetivo: Avaliar parâmetros de estresse oxidativo em pacientes com acidúria 3-hidroxi-3-metilglutárica antes e após o tratamento. Materiais e Métodos: Amostras de sangue e urina foram coletadas de pacientes no momento do diagnóstico e após tratamento com dieta com restrição de proteínas e suplementação de L-carnitina (100mg/kg/dia) e de controles. O TBA, um subproduto final da peroxidação lipídica, foi medido no plasma. A determinação do teor de carbonilas e de grupos sulfidrila, marcadores de dano oxidativo a proteínas, foi realizada no plasma. Para avaliar na urina a oxidação de proteínas, os níveis de di-tirosina foram medidos por autofluorescência. O ensaio da capacidade antioxidante urinária foi realizado utilizando um kit comercial. Os níveis de carnitina livre e isovalerilcarnitina foram analisados em amostras de sangue por espectrometria de massas em tandem usando o método de monitorização de reação múltipla (MRM). A concentração de proteínas foi determinada pelo método de biureto em amostras de plasma usando um kit comercial. Resultados e Discussão: Os resultados demonstraram um aumento significativo nos níveis de isovalerilcarnitina em sangue total, das concentrações plasmáticas de malondialdeído e urinárias de di-tirosina, além de uma redução significativa da capacidade antioxidante urinária e dos níveis sanguíneos de carnitina livre nos pacientes no momento do diagnóstico em relação aos controles. Verificou-se uma diminuição nas concentrações do malondialdeído plasmático e da di-tirosina na urina dos pacientes tratados, o que sugere um efeito de proteção do tratamento sobre a peroxidação de lípidos e do dano oxidativo a proteínas, bem como uma normalização dos níveis de L-carnitina durante o tratamento. Conclusões: Esses resultados permitem sugerir que o estresse oxidativo ocorre em pacientes com acidemia 3-hidroxi-3-metilglutárica e que o tratamento com a dieta restrita de proteína e suplementada com L-carnitina pode oferecer proteção contra o dano oxidativo a biomoléculas. / Introduction: The 3-hydroxy-3-methylglutaric acidemia is caused by the deficiency of 3-hydroxy-3-methyl-glutaryl-CoA lyase, an enzyme of leucine metabolism, leading to accumulation of 3-hydroxy-3-methylglutaric acid in tissues. Studies have suggested that oxidative stress may contribute to the neurological damage observed in some organic acidurias. Objective: Evaluate oxidative stress parameters in patients with 3-hydroxy-3-methylglutaric aciduria patiets before and after treatment. Materials and Methods: Blood and urine samples were collected from patients at diagnosis and after treatment with restricted protein diet and supplemented with L-carnitine (100mg/kg/dia) and from controls. TBA , an end subproduct of lipid peroxidation, was measured in plasma. Determination of carbonyl and sulphydryl content, biomarkers of oxidative damage to proteins, was done in plasma. To assess urine protein oxidation, levels of di-tyrosine were measured by autofluorescence. The assay of antioxidant urinary capacity was performed using a commercial kit. The levels of free carnitine and isovalerylcarnitine were analyzed in blood samples by tandem mass spectrometry using the method of multiple reaction monitoring (MRM). Protein content was determined by the biuret method for plasma samples using a commercial kit. Results and Discussion: The results demonstrated a significant increase of total blood isovalerylcarnitine, malondialdehyde plasma concentrations and di-tyrosine urinary levels and a significant reduction of the urinary antioxidant capacity and free-carnitine blood levels in pacients at diagnosis compared to controls. It was verified a decrease in plasma malondialdehyde concentrations and urinary di-tyrosine levels in treated patients, suggesting a protective effect of the treatment on lipid peroxidation and protein oxidative damage, as well as a normalization of L-carnitine levels during treatment. Conclusions: These results allow to suggest that oxidative stress occurs in 3-hydroxy-3-methyl-glutaryl-CoA lyase deficient patients and treatment with restricted protein diet and L-carnitine may offer protection against oxidative damage.

Introdução: A acidemia 3-hidroxi-3-metilglutárica é causada pela deficiência da 3-hidroxi-3-metil-glutaril-CoA-liase, uma enzima do metabolismo da leucina, levando ao acúmulo, especialmente, do ácido 3-hidroxi-3-metilglutárico nos tecidos. Estudos sugerem que o estresse oxidativo pode contribuir para os danos neurológicos observados em algumas acidúrias orgânicas. Objetivo: Avaliar parâmetros de estresse oxidativo em pacientes com acidúria 3-hidroxi-3-metilglutárica antes e após o tratamento. Materiais e Métodos: Amostras de sangue e urina foram coletadas de pacientes no momento do diagnóstico e após tratamento com dieta com restrição de proteínas e suplementação de L-carnitina (100mg/kg/dia) e de controles. O TBA, um subproduto final da peroxidação lipídica, foi medido no plasma. A determinação do teor de carbonilas e de grupos sulfidrila, marcadores de dano oxidativo a proteínas, foi realizada no plasma. Para avaliar na urina a oxidação de proteínas, os níveis de di-tirosina foram medidos por autofluorescência. O ensaio da capacidade antioxidante urinária foi realizado utilizando um kit comercial. Os níveis de carnitina livre e isovalerilcarnitina foram analisados em amostras de sangue por espectrometria de massas em tandem usando o método de monitorização de reação múltipla (MRM). A concentração de proteínas foi determinada pelo método de biureto em amostras de plasma usando um kit comercial. Resultados e Discussão: Os resultados demonstraram um aumento significativo nos níveis de isovalerilcarnitina em sangue total, das concentrações plasmáticas de malondialdeído e urinárias de di-tirosina, além de uma redução significativa da capacidade antioxidante urinária e dos níveis sanguíneos de carnitina livre nos pacientes no momento do diagnóstico em relação aos controles. Verificou-se uma diminuição nas concentrações do malondialdeído plasmático e da di-tirosina na urina dos pacientes tratados, o que sugere um efeito de proteção do tratamento sobre a peroxidação de lípidos e do dano oxidativo a proteínas, bem como uma normalização dos níveis de L-carnitina durante o tratamento. Conclusões: Esses resultados permitem sugerir que o estresse oxidativo ocorre em pacientes com acidemia 3-hidroxi-3-metilglutárica e que o tratamento com a dieta restrita de proteína e suplementada com L-carnitina pode oferecer proteção contra o dano oxidativo a biomoléculas. / Introduction: The 3-hydroxy-3-methylglutaric acidemia is caused by the deficiency of 3-hydroxy-3-methyl-glutaryl-CoA lyase, an enzyme of leucine metabolism, leading to accumulation of 3-hydroxy-3-methylglutaric acid in tissues. Studies have suggested that oxidative stress may contribute to the neurological damage observed in some organic acidurias. Objective: Evaluate oxidative stress parameters in patients with 3-hydroxy-3-methylglutaric aciduria patiets before and after treatment. Materials and Methods: Blood and urine samples were collected from patients at diagnosis and after treatment with restricted protein diet and supplemented with L-carnitine (100mg/kg/dia) and from controls. TBA , an end subproduct of lipid peroxidation, was measured in plasma. Determination of carbonyl and sulphydryl content, biomarkers of oxidative damage to proteins, was done in plasma. To assess urine protein oxidation, levels of di-tyrosine were measured by autofluorescence. The assay of antioxidant urinary capacity was performed using a commercial kit. The levels of free carnitine and isovalerylcarnitine were analyzed in blood samples by tandem mass spectrometry using the method of multiple reaction monitoring (MRM). Protein content was determined by the biuret method for plasma samples using a commercial kit. Results and Discussion: The results demonstrated a significant increase of total blood isovalerylcarnitine, malondialdehyde plasma concentrations and di-tyrosine urinary levels and a significant reduction of the urinary antioxidant capacity and free-carnitine blood levels in pacients at diagnosis compared to controls. It was verified a decrease in plasma malondialdehyde concentrations and urinary di-tyrosine levels in treated patients, suggesting a protective effect of the treatment on lipid peroxidation and protein oxidative damage, as well as a normalization of L-carnitine levels during treatment. Conclusions: These results allow to suggest that oxidative stress occurs in 3-hydroxy-3-methyl-glutaryl-CoA lyase deficient patients and treatment with restricted protein diet and L-carnitine may offer protection against oxidative damage.

Orientadores: Anibal Eugenio Vercesi, Mariana Pinheiro Fernandes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-15T13:38:04Z (GMT). No. of bitstreams: 1 Costa_RuteAlvesPereirae_M.pdf: 1931770 bytes, checksum: c11c3126a7042737485a72a01e8020a7 (MD5) Previous issue date: 2010 / Resumo: Estatinas são fármacos amplamente utilizadas no tratamento das hipercolesterolemias. Elas são inibidores competitivos da 3-hidroxi 3-metilglutaril coenzima A (HMG-CoA) redutase impedindo, dessa forma, a síntese do colesterol. L-carnitina é sintetizada a partir dos aminoácidos essenciais lisina e metionina no fígado e no rim. Desempenha função importante na célula onde está envolvida na oxidação dos ácidos graxos agindo como um cofator no transporte de grupos acil através da membrana mitocondrial interna. Piracetam é uma droga nootropica cuja função é melhorar o desempenho cognitivo, e as funções envolvidas nos processos de aprendizagem, memória, atenção e consciência. O presente trabalho teve como objetivo avaliar a ação protetora da Lcarnitina ou piracetam contra a morte por necrose de células PC-3 induzida por sinvastatina 60 µM ou tert-butyl-hidroperóxido (t-BOOH) 500 µM. Tanto a sinvastatina quanto o t-BOOH causam transição de permeabilidade mitocondrial (TPM), seguida de morte celular por necrose. L-carnitina e piracetam protegeram contra a morte celular induzida por sinvastatina ou t-BOOH por meio de um mecanismo dose-dependente (1- 12 µM). Na avaliação da disfunção mitocondrial causada por sinvastatina ou t-BOOH, tanto a L-carnitina quanto o piracetam protegeram contra a perda de potencial de membrana mitocondrial de forma semelhante à ciclosporina A. As quedas nas velocidades de respiração de estado III e estado IV, (fosforilação e repouso), também foram prevenidas por L-carnitina, piracetam e ciclosporina A. Quando linhagens de células não tumorais (GN16-P6 e HaCaT) foram analisadas, observou-se que tanto Lcarnitina quanto o piracetam também protegeram contra a morte celular induzida por sinvastatina. Podemos concluir que nas células PC-3, estes compostos protegem contra necrose celular através da inibição da TPM e que em linhagens não tumorais estes compostos apresentam efeitos semelhantes. / Abstract: Statins are drugs widely used in the treatment of hypercholesterolemia. They are competitive inhibitors of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase preventing in this way, the synthesis of cholesterol. L-carnitine is synthesized from the essential aminoacids lysine and methionine in liver and kidney and plays na important role in the cell, where it is involved in fatty acid oxidation by acting as a cofactor in the transport of acyl groups across the inner mitochondrial membrane. Piracetam is a nootropic drug which function is to improve cognitive performance, and the functions involved in the processes of learning, memory, attention and consciousness. This study aimed to evaluate the protective action of L-carnitine or piracetam against necrosis in PC-3 cells induced by 60 µM simvastatin or 500 µM tertbutyl- hydroperoxide (t-BOOH). Both simvastatin and t-BOOH causes mitochondrial permeability transition (MPT) followed by necrosis. L-carnitine and piracetam protected against cell death induced by simvastatin or t-BOOH by a dose-dependent mechanism (1-12 µM). In the assessment of mitochondrial dysfunction caused by simvastatin or t- BOOH, L-carnitine or piracetam similarly to cyclosporin A protected against the loss of mitochondrial membrane potential. The decrease in state III or state IV respiration rates, were also prevented. When non-tumor cell lines (GN16-P6 and HaCaT) were analyzed, it was observed that both L-carnitine and piracetam also protected against cell death induced by simvastatin. We can conclude that these compounds protected against cell necrosis by inhibiting MPT in both tumor or non tumor cell lines. / Mestrado / Biologia Estrutural, Celular, Molecular e do Desenvolvimento / Mestre em Fisiopatologia Médica

La modification des profils spécifiques en acides gras (AG) dans des huiles végétales peut servir à l’amélioration de leur qualité nutritionnelle, mais également à l’émergence d’une industrie biosourcée où les AG peuvent représenter une alternative aux ressources carbonées fossiles. Cependant des difficultés à modifier le profil en AG des huiles végétales, partagées par l’ensemble des équipes de recherche impliquées subsistent. Bien que la biosynthèse des AG est aujourd’hui bien caractérisée chez les plantes, des incertitudes persistent concernant les voies de transfert des AG du pool d’acyl-CoA vers les précurseurs lipidiques, et les formes de transport entre les différents compartiments impliqués dans les synthèses lipidiques. La carnitine est un acteur essentiel du trafic intracellulaire des AG chez l’animal et la levure. La présence avérée chez la plante d’acyl-Carnitines au côté de la carnitine libre, et la mise en évidence d’activités enzymatiques associées, prouvent également le lien entre la carnitine et le métabolisme des AG. Le travail de cette thèse a donc porté sur un approfondissement des connaissances sur le rôle de la carnitine dans le métabolisme lipidique chez Arabidopsis thaliana. A ce titre, nous avons pu montrer par LC-QQQ-MS/MS dans nos extraits végétaux, que l’oléoyl-, la palmitoyl- et la stéaroyl-Carnitine sont les espèces majoritaires et correspondent aux 3 AG (C18:1, C16:0 et C18:0) principalement synthétisés et exportés des plastes, pour alimenter la synthèse lipidique de la voie eucaryotique. De plus, une augmentation significative des teneurs en acyl-Carnitines a été mesurée dans des processus développementaux nécessitant une forte synthèse de glycérolipides, tels que le développement post-Germinatif (2 j post-Imbibition) ou lors de l’organogenèse racinaire, en concomitance avec le niveau d’expression des gènes marqueurs de la synthèse lipidique eucaryotique. D’autre part, la comparaison des teneurs en acyl-Carnitines et en carnitine estérifiée a révélée un résultat inédit montrant qu’une grande fraction de la carnitine est estérifiée à des AG inhabituels ou des acides organiques que nous cherchons actuellement à identifier par LC-QTOF-MS/MS. Ainsi, l’ensemble de nos résultats suggèrent que la carnitine pourrait être impliquée dans le trafic intracellulaire d’AG pour la synthèse de lipides eucaryotiques et de lipides particuliers et/ou dans la prise en charge d’acides organiques encore non identifiés dans les plantes. / Specific modification of fatty acid profiles (FA) in vegetable oils can help to improve their nutritional quality but also to the development of a bio-Based industry where FA may represent an alternative to fossil fuel sources. However problems to modify the FA profile of vegetable oils still remain and are shared by all the teams involved. Although the biosynthesis of AG is now well characterized in plants, uncertainties remain about the tranfert of AG of acyl-CoA pool to lipid precursors and the forms of transport between different compartments involved in lipid synthesis. Carnitine plays an essential role in intracellular trafficking of FA in animals and yeast. The known presence of acyl-Carnitines in plant alongside the free carnitine, and measurement of associatied-Enzymatic activities also show the link between FA metabolism and carnitine. During this thesis we tried to improve our understanding of the role of carnitine in lipid metabolism in Arabidopsis thaliana. We have shown by LC-QQQ-MS / MS in our plant extracts that oleoyl-, palmitoyl- and stearoyl-Carnitine are the predominant species and correspond to the three main AG (C18:1, C16:0 and C18:0) synthesized and exported from the plastids to supply the lipid synthesis of the eukaryotic pathway. Moreover, a significant increase of the levels of acyl-Carnitines were measured in developmental processes requiring high glycerolipid synthesis, such as the post-Germinative growth (2 days post-Imbibition) during root organogenesis, concomitantly with the level of expression of the eukaryotic lipid synthesis marker genes. Furthermore, comparison of the levels of acyl-Carnitine and carnitine ester revealed an unpublished results showing that a large fraction of carnitine is esterified to unusual FA or organic acids that we are currently identifing by LC QTOF-MS/MS. Thus, all of our results suggest that carnitine could be involved in the intracellular traffic of FA for the synthesis of lipids and particular eukaryotic lipids and/or in the transport of yet unidentified organic acids in plants.

No description available.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24287号 / 医博第4903号 / 新制||医||1061(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 寺田 智祐, 教授 松田 道行, 教授 YOUSSEFIAN Shohab / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM