Publication: Biocumulación, toxicidad e interacción de metilmercurio y especies de selenio
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2017-05-08
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Universidad Complutense de Madrid
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Abstract
El metilmercurio (MeHg) es uno de los compuestos de mercurio más tóxicos presente en el medioambiente. Desde los años setenta se sabe que el 99% de las especies de mercurio en el plasma sanguíneo son capaces de unirse a los grupos tioles de las proteínas pudiendo así transportarse desde la sangre a diversos órganos. La acumulación de MeHg en el riñón y el hígado es capaz de inducir cambios patológicos en ambos órganos. El mecanismo por el cual el MeHg ejerce su toxicidad no está bien definido. Por este motivo uno de los objetivos de la presente Tesis es la evaluación de la toxicidad ejercida por el MeHg mediante en el empleo de técnicas de biología molecular y estrategias de proteómica cuantitativa(SILAC y iTRAQ). Por otro lado, el selenio es un micronutriente esencial que forma parte de algunas enzimas (glutation peroxidasa y 1-iodotironia 5-deiodinasa). Además, hay evidencias de que algunos de los compuestos de selenio (Se-metilselenocisteína en particular) son capaces de actuar frente a diversos tipos de cáncer. Otra característica adicional a destacar de los compuestos de selenio es la capacidad de reducir los efectos tóxicos de los compuestos de mercurio. Para tener un conocimiento más profundo de los hechos anteriormente mencionados, en la presente Tesis se han realizado estudios in vitro enfocados hacia la evaluación del papel del selenio como agente antioxidante y protector de los efectos tóxicos causados por el metilmercurio en células de hepatoma humano (Hep G2)...
Methylmercury (MeHg) is the most important form of mercury in terms of toxicity from environmental exposure making it a persistent health concern. It has been known since at least the early 1970s that 99% of mercury species circulating in blood plasma are bound to protein bound thiol groups and it was speculated that this is the mechanism of transport of mercury into organs. Severe MeHg accumulation in the kidney and the liver induces pathological changes in these organs. MeHg has been suggested to exert toxicity through multiple mechanisms but the precise biochemical machinery by which MeHg induces cytotoxicity has not been fully defined, therefore, one of the objectives of this thesis was the evaluation of biomolecular mechanisms of MeHg-Induced toxicity through molecular biology techniques and proteomic strategies (SILAC and iTRAQ). On the other hand, selenium is an essential micronutrient for humans and also a constituent of enzymes (such as glutathione peroxidase and 1-iodothyronine 5- deiodinase). In addition, it is recognised that Se-compounds - particularly Se- Methylselenocysteine (Se-MeCys) - provide protection against various forms of cancer. Furthermore, interactions between Mercury and Selenium are arousing high interest because a protective function of Se against toxic effects caused by mercury has been reported. To prove all the facts mentioned above and to get a deeper knowledge of the protection properties of selenocompounds, the current thesis presents an in-vitro study were the protective effect of selenium against oxidative stress and toxic effects caused by methylmercury in human hepatocytes (Hep G2) were evaluated...
Methylmercury (MeHg) is the most important form of mercury in terms of toxicity from environmental exposure making it a persistent health concern. It has been known since at least the early 1970s that 99% of mercury species circulating in blood plasma are bound to protein bound thiol groups and it was speculated that this is the mechanism of transport of mercury into organs. Severe MeHg accumulation in the kidney and the liver induces pathological changes in these organs. MeHg has been suggested to exert toxicity through multiple mechanisms but the precise biochemical machinery by which MeHg induces cytotoxicity has not been fully defined, therefore, one of the objectives of this thesis was the evaluation of biomolecular mechanisms of MeHg-Induced toxicity through molecular biology techniques and proteomic strategies (SILAC and iTRAQ). On the other hand, selenium is an essential micronutrient for humans and also a constituent of enzymes (such as glutathione peroxidase and 1-iodothyronine 5- deiodinase). In addition, it is recognised that Se-compounds - particularly Se- Methylselenocysteine (Se-MeCys) - provide protection against various forms of cancer. Furthermore, interactions between Mercury and Selenium are arousing high interest because a protective function of Se against toxic effects caused by mercury has been reported. To prove all the facts mentioned above and to get a deeper knowledge of the protection properties of selenocompounds, the current thesis presents an in-vitro study were the protective effect of selenium against oxidative stress and toxic effects caused by methylmercury in human hepatocytes (Hep G2) were evaluated...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, Departamento de Química Analítica, leída el 22/01/2016. Tesis formato europeo (compendio de artículos)