Land use and population densities influence contaminant concentrations in aquatic organisms. It is increasingly common to monitor the marine environment and establish geographic trends of environmental contamination by measuring contaminant levels in animals from higher trophic levels. In this work we chose the common bottlenose dolphin (Tursiops truncatus) as a top level predator to monitor a site on the Georgia coast 62 the US, known to be heavily contaminated by Aroclor 1268, an uncommon PCB mixture primarily comprised of octa- through deca-chlorobiphenyl congeners. Prior studies have suggested an association between high polychlorinated biphenyls (PCBs) concentrations and increased risk of infectious disease suggesting a causal link between persistent organic pollutants (POPs) exposure, immune function and susceptibility to disease. We are currently investigating the potential for identifying PCBs exposure in bottlenose dolphins through screening for their immunological and/or endocrine perturbations associated with exposure using microarray technology and gene expression profile analysis. A newly developed dolphin oligo microarray representing 24,418 unigene sequences was used to analyze blood samples from 69 dolphins collected from 5 geographic locations (Beaufort, NC, Sarasota Bay, FL, Saint Joseph Bay, FL, Sapelo Island, GA and Brunswick, GA). The Georgia samples were selected due to the measured high concentrations of PCBs contaminants in their blubber. Genes involved in xenobiotic metabolism, in development/differentiation and oncogenic pathways were found to be differentially expressed in GA dolphins compared to the other locations. Hypothyroidism has been previously described in GA dolphins and, interestingly, a few of the genes that we identified are involved in the proper function of the thyroid. The analysis of GA animals alone, correlated with contaminant load measured, showed the activation of genes involved in stress response, DNA repair and skin damage, UV and/or viral infection-induced. If successful, the gene expression profile analysis could provide a cost-effective means to screen for indicators of chemical toxin exposure as well as disease status in top level predators. The transcriptomic data analysis will be a first step towards identification of markers/patterns indicative of exposure to chemical contaminants and will promote an understanding of toxic mechanisms and/or pathways that are currently not well understood in marine mammals.

The Strange Case of Georgia Dolphins: the effects of environmental changes on the transcriptome

MANCIA, Annalaura;ABELLI, Luigi;
2014

Abstract

Land use and population densities influence contaminant concentrations in aquatic organisms. It is increasingly common to monitor the marine environment and establish geographic trends of environmental contamination by measuring contaminant levels in animals from higher trophic levels. In this work we chose the common bottlenose dolphin (Tursiops truncatus) as a top level predator to monitor a site on the Georgia coast 62 the US, known to be heavily contaminated by Aroclor 1268, an uncommon PCB mixture primarily comprised of octa- through deca-chlorobiphenyl congeners. Prior studies have suggested an association between high polychlorinated biphenyls (PCBs) concentrations and increased risk of infectious disease suggesting a causal link between persistent organic pollutants (POPs) exposure, immune function and susceptibility to disease. We are currently investigating the potential for identifying PCBs exposure in bottlenose dolphins through screening for their immunological and/or endocrine perturbations associated with exposure using microarray technology and gene expression profile analysis. A newly developed dolphin oligo microarray representing 24,418 unigene sequences was used to analyze blood samples from 69 dolphins collected from 5 geographic locations (Beaufort, NC, Sarasota Bay, FL, Saint Joseph Bay, FL, Sapelo Island, GA and Brunswick, GA). The Georgia samples were selected due to the measured high concentrations of PCBs contaminants in their blubber. Genes involved in xenobiotic metabolism, in development/differentiation and oncogenic pathways were found to be differentially expressed in GA dolphins compared to the other locations. Hypothyroidism has been previously described in GA dolphins and, interestingly, a few of the genes that we identified are involved in the proper function of the thyroid. The analysis of GA animals alone, correlated with contaminant load measured, showed the activation of genes involved in stress response, DNA repair and skin damage, UV and/or viral infection-induced. If successful, the gene expression profile analysis could provide a cost-effective means to screen for indicators of chemical toxin exposure as well as disease status in top level predators. The transcriptomic data analysis will be a first step towards identification of markers/patterns indicative of exposure to chemical contaminants and will promote an understanding of toxic mechanisms and/or pathways that are currently not well understood in marine mammals.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1958218
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