Premium
Mechanisms of cadmium‐induced production of reactive oxygen species (ROS) by mitochondria of a model marine mollusk, Crassostrea virginica
Author(s) -
Overton Robert A.,
Sokolova Inna
Publication year - 2006
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.20.5.a1457-a
Subject(s) - reactive oxygen species , crassostrea , mitochondrial ros , cadmium , oxidative stress , mitochondrion , oyster , chemistry , biochemistry , biology , ecology , organic chemistry
Marine mollusks such as oysters are exposed to cadmium in estuaries, which is a toxic metal strongly disrupting mitochondrial physiology. Our previous studies have shown that exposure to cadmium results in oxidative damage of oyster tissues as indicated by accumulation of malondialdehyde, a biomarker of lipid peroxidation. However, the mechanisms of cadmium‐induced oxidative stress in oysters are not known. Our study aims to investigate the effects of cadmium on ROS production in mitochondria of eastern oysters, Crassostrea virginica and to determine key sites of cadmium‐induced ROS production. We measured ROS formation at respiratory complexes I, III and IV in isolated mitochondria using complex‐specific substrates and inhibitors and a ROS‐sensitive fluorescent dye, dihydrorhodamine. Our data show that respiratory complexes I, III and IV contribute 16, 45 and 39% to the mitochondrial ROS production in control oysters at 20°C. In vitro exposure to 50 μM Cd 2+ resulted in a 1.5‐fold increase in overall ROS production by oyster mitochondria respiring on pyruvate compared to the control. ROS production at complex III exhibited a 2.5 fold increase in Cd‐exposed mitochondria, while ROS production at complex IV decreased by 97% likely reflecting Cd‐induced inhibition of cytochrome c oxidase activity. Future studies will investigate the synergistic effects of temperature and cadmium on ROS production and its relationship to increased oxidative stress with increasing temperature in cadmium exposed oysters. Supported by NSF and the APS Undergraduate Summer Research Fellowship.