Contaminant loading in remote Arctic lakes affects cellular stress-related proteins expression in feral charr
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The remote Arctic lakes on Bjørnøya Island, Norway, offer a unique opportunity to study possible affect of lifelong contaminant exposure in wild populations of landlocked Arctic charr (Salvelinus alpinus). This is because Lake Ellasjøen has persistent organic pollutant (POP) levels that are significantly greater than in the nearby Lake Øyangen. We examined whether this differential contaminant loading was reflected in the expression of protein markers of exposure and effect in the native fish. We assessed the expressions of cellular stress markers, including cytochrome P4501A (Cyp1A), heat shock protein 70 (hsp70), and glucocorticoid receptor (GR) in feral charr from the two lakes. The average polychlorinated biphenyl (PCB) load in the charr liver from Ellasjøen was approximately 25-fold higher than in individuals from Øyangen. Liver Cyp1A protein expression was significantly higher in individuals from Ellasjøen compared with Øyangen, confirming differential PCB exposure. There was no significant difference in hsp70 protein expression in charr liver between the two lakes. However, brain hsp70 protein expression was significantly elevated in charr from Ellasjøen compared with Øyangen. Also, liver GR protein expression was significantly higher in the Ellasjøen charr compared with Øyangen charr. Taken together, our results suggest changes to cellular stress-related protein expression as a possible adaptation to chronic-contaminant exposure in feral charr in the Norwegian high-Arctic.
KeywordsCyp1A hsp70 Glucocorticoid receptor Salvelinus alpinus PCB Salmonid Fish
We thank Guttorm Christensen and Anita Evenset who collected the fish tissue samples for us at Bjørnøya Island. The study was funded by the Norwegian Research Council, project no. 114263/720 and the Natural Sciences and Engineering Research Council (NSERC, Canada) discovery grant.
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