Oxidative stress, lipid metabolism, and neurotransmission in freshwater snail (Pomacea patula) exposed to a water-accommodated fraction of crude oil

Background. Crude oil is a super mixture of chemical compounds and is commonly found in aquatic environments. The tegogolo (Pomacea patula Baker, 1922) is a Mexican freshwater snail endemic to Lake Catemaco in Veracruz; currently, however, its distribution has expanded to many freshwater ecosystems that suffer the impact of crude oil spills and oil byproducts like fuels. Goals. To assess a series of biomarkers involved in oxidative stress, neurotransmission, and fatty acid metabolism in tegogolos exposed to the water-accommodated fraction (WAF) of Maya crude oil (MCO). Methods. Tegogolo specimens were exposed to WAF of MCO obtained from loads of 0.1, 1, 10 and 100 mg/L. We evaluated ROS ( O2 -* and H2O2), oxidative stress (TBARS and RC=O), enzymes involved in antioxidant defense (SOD, CAT, and GPx), some enzymes involved in neurotransmission (AChE, GDA, and CbE activities), and biomarkers of fatty acids metabolism (fatty acids levels and AOX activity). Results. Clear biomarkers responses were observed only in some tissues. ROS were clearly higher than controls in the foot, head, and kidney; however, others biomarkers of oxidative stress remain statistically unchanged. SOD response was irregular with respect to controls and treatments. In contrast, CAT (foot) and GPx (foot and intestine) were the more active enzymes and their activities were higher than in controls. The responses of some enzymes involved in neurotransmission suggest that compensation mechanisms exist between AChE and GDA in the foot and head. Fatty acids metabolism increased with exposure to WAF; however, these types of biomarkers seem unsuitable for monitoring the toxic effects produced by WAF at low environmental concentrations. Conclusions. We can conclude that under the exposure conditions discussed herein, the tegogolos showed acclimation to WAF of Maya crude oil by complex mechanisms.Background. Crude oil is a super mixture of chemical compounds and is commonly found in aquatic environments. The tegogolo (Pomacea patula Baker, 1922) is a Mexican freshwater snail endemic to Lake Catemaco in Veracruz; currently, however, its distribution has expanded to many freshwater ecosystems that suffer the impact of crude oil spills and oil byproducts like fuels. Goals. To assess a series of biomarkers involved in oxidative stress, neurotransmission, and fatty acid metabolism in tegogolos exposed to the water-accommodated fraction (WAF) of Maya crude oil (MCO). Methods. Tegogolo specimens were exposed to WAF of MCO obtained from loads of 0.1, 1, 10 and 100 mg/L. We evaluated ROS ( O2-* and H2O2), oxidative stress (TBARS and RC=O), enzymes involved in antioxidant defense (SOD, CAT, and GPx), some enzymes involved in neurotransmission (AChE, GDA, and CbE activities), and biomarkers of fatty acids metabolism (fatty acids levels and AOX activity). Results. Clear biomarkers responses were observed only in some tissues. ROS were clearly higher than controls in the foot, head, and kidney; however, others biomarkers of oxidative stress remain statistically unchanged. SOD response was irregular with respect to controls and treatments. In contrast, CAT (foot) and GPx (foot and intestine) were the more active enzymes and their activities were higher than in controls. The responses of some enzymes involved in neurotransmission suggest that compensation mechanisms exist between AChE and GDA in the foot and head. Fatty acids metabolism increased with exposure to WAF; however, these types of biomarkers seem unsuitable for monitoring the toxic effects produced by WAF at low environmental concentrations. Conclusions. We can conclude that under the exposure conditions discussed herein, the tegogolos showed acclimation to WAF of Maya crude oil by complex mechanisms.Background. Crude oil is a super mixture of chemical compounds and is commonly found in aquatic environments. Thetegogolo (Pomacea patula Baker, 1922) is a Mexican freshwater snail endemic to Lake Catemaco in Veracruz; currently,however, its distribution has expanded to many freshwater ecosystems that suffer the impact of crude oil spills and oilbyproducts like fuels. Goals. To assess a series of biomarkers involved in oxidative stress, neurotransmission, and fatty acidmetabolism in tegogolos exposed to the water-accommodated fraction (WAF) of Maya crude oil (MCO). Methods. Tegogolospecimens were exposed to WAF of MCO obtained from loads of 0.1, 1, 10 and 100 mg/L. We evaluated ROS ( O2-* and H2O2),oxidative stress (TBARS and RC=O), enzymes involved in antioxidant defense (SOD, CAT, and GPx), some enzymes involvedin neurotransmission (AChE, GDA, and CbE activities), and biomarkers of fatty acids metabolism (fatty acids levels and AOXactivity). Results. Clear biomarkers responses were observed only in some tissues. ROS were clearly higher than controls inthe foot, head, and kidney; however, others biomarkers of oxidative stress remain statistically unchanged. SOD response wasirregular with respect to controls and treatments. In contrast, CAT (foot) and GPx (foot and intestine) were the more activeenzymes and their activities were higher than in controls. The responses of some enzymes involved in neurotransmission suggestthat compensation mechanisms exist between AChE and GDA in the foot and head. Fatty acids metabolism increasedwith exposure to WAF; however, these types of biomarkers seem unsuitable for monitoring the toxic effects produced by WAFat low environmental concentrations. Conclusions. We can conclude that under the exposure conditions discussed herein,the tegogolos showed acclimation to WAF of Maya crude oil by complex mechanisms

Intercalibración de las pruebas con Daphnia magna y Pseudokirchneriella subcapitata en México: herramientas potenciales para el monitoreo ambiental

In Mexico, as in other developing countries, the knowledge about pollution status and its effects in local ecosystems has been developed following specific research goals that make use of different methodologies. Since there are information gaps in this topic, it is important to promote the broad use of standardized ecotoxicity protocols as regulatory tools to establish comprehensive environmental protection measures. From this perspective, the goal of this study was to demonstrate, through intercalibration exercises, with previous capacity homologation workshops, the potential of Daphnia magna and Pseudokirchneriella subcapitata (known before as Selenastrum capricornutum) protocols, to generate analytically reliable results in laboratories with little experience in this field. This will allow the promotion of bio-analytical tools in Mexico for environmental monitoring, which will favor the integral evaluation of pollution in water bodies. The results of the laboratories internal calibration exercises demonstrated that in a short term it is possible to achieve an acceptable analytical repeatability and an adequate performance of the protocols, which sustains the idea that these protocols are good environmental monitoring tools, even in countries where today there are very few qualified human resources and laboratories fit for this purpose.En México, como en otros países en desarrollo, el conocimiento sobre el grado de contaminación y sus efectos en los ecosistemas locales se ha generado siguiendo objetivos de investigación específicos que emplean metodologías de distinta naturaleza. Dado que aún existen vacíos de información en el tema, es importante impulsar el uso generalizado de pruebas ecotoxicológicas que empleen protocolos estandarizados y que sirvan como herramientas regulatorias para establecer medidas integrales de protección al ambiente. Por lo anterior, el presente estudio tuvo como objetivo demostrar, a través de ejercicios de intercalibración, previo desarrollo de talleres de homologación de capacidades, el potencial de los protocolos de ensayo con Daphina magna y Pseudokirchneriella subcapitata (antes Selenastrum capricornutum) para generar resultados confiables en laboratorios con poca experiencia en este campo. Esto permitirá impulsar el empleo de herramientas bioanalíticas en México para el monitoreo ambiental, las cuales favorecen la evaluación integral de los problemas de contaminación en los cuerpos de agua. Los resultados de los ejercicios de calibración interna de los laboratorios demostraron que en un corto plazo es posible lograr una repetibilidad aceptable en las pruebas y un desempeño adecuado de los protocolos, lo cual apoya la idea de que estos protocolos son pertinentes para su empleo en programas de monitoreo ambiental, aún en países donde actualmente se cuenta con pocos recursos humanos capacitados y laboratorios aptos para tal fin

Evaluación de la toxicidad de hidrocarburos poliaromáticos en un sistema acuático y su aplicación en la ponderación de evidencias

Tesis (Maestría en Ciencias), Instituto Politécnico Nacional, SEPI, ENCB, 2008, 1 archivo PDF, (177 páginas). tesis.ipn.m