Premium
Mitochondrial aconitase is sensitive to oxidative stress induced by cadmium and elevated temperatures but not protected by uncoupling proteins in eastern oysters Crassostrea virginica
Author(s) -
Sanni Basharat,
Cherkasov Anton,
Sokolova Inna M.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a819-d
Subject(s) - aconitase , crassostrea , oyster , oxidative stress , mitochondrion , antioxidant , cadmium , chemistry , glutathione , mitochondrial ros , biology , biochemistry , ecology , enzyme , organic chemistry
Heavy metals such as cadmium (Cd) and temperature are common environmental stressors in estuaries. We studied the effects of Cd and temperature on oxidative stress using mitochondrial aconitase as a biomarker and assessed the role of uncoupling proteins (UCPs) in antioxidant protection in oysters, Crassostrea virginica. Our results show that exposure of mitochondria to Cd in vitro results in elevated ROS production and aconitase inactivation, especially at elevated temperatures. In contrast, during exposure of oysters to 50 μg L −1 Cd in vivo , no inhibition of aconitase was detected; in fact, aconitase activity was slightly higher in Cd‐exposed oysters. This suggests that aconitase expression may be up‐regulated in vivo to offset the Cd‐induced damage. Acclimation of oysters at 28°C led to a 40–50% decrease in aconitase activity compared to 12 or 20°C. Inhibition of UCPs with ATP, GDP or BSA, or their activation with free fatty acids had no effect on aconitase, thus providing no indication for UCP involvement in antioxidant defense in oysters. The results of this study indicate that temperature stress exaggerates toxicity of Cd and inhibits aconitase in oyster mitochondria, which may have important implications for oyster survival in polluted environments during seasonal warming and/or global climate change. Supported by NSF IBN‐0347238 and APS Undergraduate Summer Research Fellowship.