Polychaetes, Eurythoe complanata, from the Gulf of Cariaco,Venezuela, were exposed to 0.3, 1.6, and 3.3% water-soluble fraction (WSF) of used crankcase oil during 15 and 21 days. The antioxidant enzymes glutathione peroxidase (GPX), glutathione reductase (GR), catalase (CAT), and glutathione-S-transferase (GST) were assayed in the body wall tissue. Furthermore, after chemical exposure, the polychaetes were cut into equal halves; then wound healing and the number of regenerated body segments were recorded periodically. GST activity was affected by all the experimental treatments, with activity increasing with WSF concentrations. GPx activity was altered for the contamination period. GR and CAT activities rose in response to increasing WSF concentrations, and were higher for long-term than for short-term exposures. The wound healing of the transected body regions was retarded by WSF exposure. WSF affected the tissue regeneration, which was almost abolished at 3.3% WSF. The exposure period did not affect the tissue-repairing responses. Alteration of GST in contaminated organisms suggested equivalent changes in detoxication of bioaccumulated organic contaminants. The variation of GR and CAT suggests induction of oxidative stress that could reduce the ability of WSF-exposed worms to repair damaged tissue.

No abstract

No abstract

INTRODUCCIÓNLos niveles de metales pesados en algunas zonas costeras del estado Sucre (Venezuela) han incrementado recientemente a causa antropogénica (Martínez 2002 ABSTRACT. The green mussel Perna viridis has been used as a sentinel organism in marine and coastal ecosystem health assessments. In this study the degree of contamination at three sites on the coast of Sucre State (Venezuela) was analyzed using molecular, cellular, and immunological biomarkers in P. viridis. Specimens were collected from Chacopata-Guayacán (CG, Araya Peninsula), Río Caribe (RC, Paria Peninsula), and San Antonio del Golfo (SAG, southern Gulf of Cariaco). We determined the concentration of heavy metals in the soft tissue of each individual, as well as the total number, viability, phagocytosis, and stability of the lysosomal membranes in hemocytes. The oxidative damage to lipids (TBARS), sulfhydryl group levels, total proteins, and lysozyme activity were quantified in the digestive gland. The results revealed high concentrations of Zn, Cr, and Cd in the organisms from CG. The total hemolymph cell count was lower in organisms from RC and CG. A slight increase in the number of phagocytes was observed in the organisms from RC and CG relative to those from SAG. The highest percentage of hemocytes with destabilized lysosomal membranes was recorded for the organisms from CG, followed by RC, indicating a weak association with the content of peroxidized lipids (TBARS); these values could be associated with the body loads of heavy metals. According to the results, the mussels from CG show slight signs of contamination by heavy metals, likely originated by human activities. The use of biological markers to estimate the effect of heavy metals on sentinel organisms is recommended.Key words: antioxidant defenses, hemocytes, lysozymes, heavy metals, Perna viridis. RESUMEN. El mejillón verdePerna viridis ha sido usado como organismo biosensor de la salud de ecosistemas marino-costeros. Por tal motivo se procedió a evaluar el grado de contaminación de tres localidades costeras del estado Sucre (Venezuela) determinando biomarcadores a nivel molecular, celular e inmunológico en P. viridis. Los ejemplares fueron recolectados en las localidades de Chacopata-Guayacán (CG, península de Araya), Río Caribe (RC, península de Paria) y San Antonio del Golfo (SAG, región sur del golfo de Cariaco). Se determinó la carga de metales pesados en el tejido blando de cada individuo. Además, se valoró el número total, la viabilidad, la fagocitosis y la estabilidad de las membranas lisosomales en los hemocitos. El daño oxidativo de lípidos (TBARS), los niveles de grupos sulfhídrilos, las proteínas totales y la actividad de la lisozima fueron cuantificados en la glándula digestiva. Los resultados evidencian altas concentraciones de Zn, Cr y Cd en organismos provenientes de CG. El número de células totales en hemolinfa fue menor en los organismos de RC y CG. En estas últimas zonas los mejillones presentaron un ligero incremento en número de fagocitos con respecto a SAG. El ...

Se dividieron grupos de poliquetos, controles y expuestos a 0.4 mg Cu +2 L -1 (2.14 mg CuSO 4 5H 2 O L -1 ; 30% 96 h-CL 50 ) por siete días, en tres grupos: sensibilizados y no sensibilizados con Micrococcus lysodeikticus para evaluar la actividad de lisozima del fluido celómico, y otro sensibilizado con levaduras inactivadas por calor para evaluar la respuesta fagocítica de los celomocitos. La lisozima fue medida a 2 h y la fagocitosis a los 15 min después de la sensibilización inmunológica. Además, se evaluó el efecto de la exposición al cobre sobre la respuesta de cicatrización en los poliquetos. Para ello, los organismos expuestos al cobre y no expuestos fueron cortados en dos mitades y mantenidos en acuarios conteniendo agua de mar (sin cobre), determinándose el porcentaje de individuos cicatrizados diariamente. Las respuestas de fagocitosis y lisozima fueron inducidas por la sensibilización e inhibidas después de la exposición al metal. Por otra parte, 60-80% de los individuos controles cicatrizaron al cabo de cuatro días, mientras que los individuos tratados con cobre no evidenciaron cicatrización en el mismo periodo de tiempo. En conclusión, la inhibición de la inducción experimental de la lisozima y la fagocitosis, y de la cicatrización en el poliqueto Eurythoe complanata por la exposición aguda al cobre, sugiere el potencial de toxicidad del metal sobre los mecanismos fisiológicos que modulan la inmunidad innata y la reparación de heridas en anélidos, funciones biológicas comunes en animales cuya supresión puede resultar en una disminuida tolerancia a infecciones microbianas.

Biochemical biomarkers are widely used for the monitoring environmental quality since they can act as early warning signals, for potential ecosystem degradation caused by contaminants. In order to investigate the acute and chronic effects of a commercial formulation of glyphosate on antioxidant defenses (glutathione peroxidase, GPx; glutathione-S-transferase, GST; and reduced glutathione, GSH) and oxidative damage (malondialdehyde levels, MDA), Eisenia sp was exposed in plastic containers to natural soils contaminated with Glyphosan SL (100 g kg -1 of soil) during 7 and 21 days. Following exposure for 21 days, another group of worms were placed on herbicide-free soils to recovery for 30 days. Treatment with the herbicide significantly affected to all the biochemical markers evaluated. Antioxidant defenses (GSH, GPx and GST) and MDA, in general, increased at both exposure periods. These results showed that Glyphosan SL; the active ingredient (glyphosate) and/or its chemical additives exerts its toxic effects in Eisenia sp by altering cellular antioxidant defenses, inducing a condition of oxidative stress. During the recuperation phase of the earthworms previously exposed for 21 days to the herbicide, GPx decreased to values similar to those of the control group and MDA although decreased, control values were not reached. These results indicate that in 30 days Eisenia sp exhibits a partial recovery of the oxidative stress induced by the herbicide exposure, probably the activation of mechanisms clearance of the Glyphosan SL metabolites justify the high levels of GSH and GST at this stage. In conclusion, herbicide exposure induced changes in the biochemical responses of Eisenia sp highlight the importance of these responses as useful tools in the evaluation of impacts by pesticides in terrestrial organisms.

With the aim of investigate the acute effects of two concentrations (25 and 100%) of N. 6 fuel oil-water-accommodated fraction (OWAF) on antioxidant enzyme activities and immunological responses, fishes Thalassophryne maculosa were sampled from the La Restiga Lagoon, Margarita island, in eastern Venezuela. The antioxidant enzymes, catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-S-transferase (GST) were measured in liver and gills. The macrophagic phagocytosis and antibacterial lysozyme activity of anterior kidney were the immune parameters examined. Increases in gill GST activity and hepatic GR activity were observed after the exposure to 25 and 100% OWAF, respectively. GPX, CAT and immune responses were not affected by the experimental treatments. Our results demonstrated that among the antioxidant enzymes tested, GR and GST activities were the most sensible to the acute treatment with fuel oil, indicating changes in the redox cellular state that may result in oxidative stress in T. maculosa.

No abstract