Response of oxidative stress transcripts in the brain of wild yellow perch (Perca flavescens) exposed to an environmental gradient of methylmercury.
Methylmercury (MeHg) exposure and adverse health effects in fishes have been documented, but the molecular mechanisms involved in toxicity have not been fully characterized. The objectives of the current study were to (1) determine whether total Hg (THg) in the muscle was predictive of MeHg concentrations in the brain of wild female yellow perch (Perca flavescens) collected from four lakes in Kejimkujik National Park, a known biological mercury (Hg) hotspot in Nova Scotia, Canada and (2) to determine whether transcripts involved in the oxidative stress response were altered in abundance in fish collected across five lakes representing a MeHg gradient. In female yellow perch, MeHg in whole brain (0.38 to 2.00μg/g wet weight) was positively associated with THg in muscle (0.18 to 2.13μg/g wet weight) (R2=0.61, p<0.01), suggesting that muscle THg may be useful for predicting MeHg concentrations in the brain. Catalase (cat) mRNA levels were significantly lower in brains of perch collected from lakes with high Hg when compared to those individuals from lakes with relatively lower Hg (p=0.02). Other transcripts (cytochrome c oxidase, glutathione peroxidase, glutathione-s-transferase, heat shock protein 70, protein disulfide isomerase, and superoxide dismutase) did not show differential expression in the brain over the gradient. These findings suggest that MeHg may be inversely associated with catalase mRNA abundance in the central nervous system of wild fishes.
['Graves|Stephanie D|SD|', 'Kidd|Karen A|KA|', 'Batchelar|Katharina L|KL|', 'Cowie|Andrew M|AM|', "O'Driscoll|Nelson J|NJ|", 'Martyniuk|Christopher J|CJ|']
D000818:Animals D001822:Body Burden D001921:Brain D002374:Catalase D015536:Down-Regulation D004784:Environmental Monitoring D005260:Female D029941:Fish Proteins D015971:Gene Expression Regulation, Enzymologic D005819:Genetic Markers D008767:Methylmercury Compounds D018482:Muscle, Skeletal D009674:Nova Scotia D018384:Oxidative Stress D010471:Perches D012333:RNA, Messenger D060888:Real-Time Polymerase Chain Reaction D014874:Water Pollutants, Chemical
Oxidative stress Fish Gene expression Metals Methyl mercury