Evaluation of potential biomarkers in natural populations of Crassostrea virginica from the Gulf of Mexico exposed to aliphatic and aromatic polycyclic hydrocarbons.

Laura Liliana López Galindo1, Edgar Alfonso López-Landavery1, Gerardo Amador2, Nancy Ramirez3, Isidro Montelongo2, Sandra Tapia Morales4 and Clara E Galindo-Sanchez5, (1)Center for Scientific Research and Higher Education at Ensenada, Marine Biotechnology, Ensenada, BJ, Mexico, (2)Technological University of the Sea of Tamaulipas (UTMART), Aquaculture, La Pesca, Soto La Marina, TM, Mexico, (3)Oceanology Research Institute (IIO), Autonomous University of Baja California (UABC), Ensenada, BJ, Mexico, (4)Autonomous University of Baja California, Faculty of Marine Sciences., Ensenada, BJ, Mexico, (5)Centro de Investigación Científica y de Educación Superior de Ensenada, Marine Biotechnology, Ensenada, BJ, Mexico
Abstract:
The interaction between crude oil and the marine environment has been studied widely due to the negative impact on its biological component. In Mexico, the Gulf of Mexico (GoM) is an area of great extraction and production of hydrocarbons where organisms are exposed to leaks and / or accidental spills that can negatively affect the populations that inhabit these areas. The oyster Crassostrea virginica is an economically important species that can be used as an indicator of environmental contamination. Samples from water, sediment and oysters were collected in diverse coastal lagoons from the GoM (La Pesca, Tampamachoco, Mecoacán, Cármen and Términos) and we determined the presence of aliphatic (AHs) and polycyclic aromatic compounds (PAHs). We performed a relative expression analysis in real-time PCR from digestive gland tissue of oysters from the different lagoons. Genes involved in stress response (Hif1α, Ahr and Arnt), xenobiotic biotransformation and excretion (Cyp302a1, Cyp10) and oxidative stress response (Ggt1 and Cat) were evaluated as potential biomarkers. The results showed that Términos lagoon had the highest concentration of AHs and PAHs in water. In sediments, Tampamachoco, Mecoacán and Términos lagoons had the highest concentration of AHs and PAHs. The relative expression of Hif1α gene showed high significant relative expression in the oysters from Mecoacán, Tampamachoco and Carmén lagoons. The Cat gene showed significant high relative expression in Tampamachoco and Cármen; meanwhile, Ggt1 was overexpressed in a control group exposed to 200 μg/L of crude oil. The Cyp10 and Cyp302a1 genes showed significantly higher expression in control organisms compared to organisms from the other lagoons. In general, we detected different concentrations of hydrocarbons in water, sediments and soft tissue of C. virginica and some potential biomarkers to evaluate stress by hydrocarbons contamination.
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