Meeting Abstract
P3.26 Tuesday, Jan. 6 Effects of cadmium exposure on mitochondrial response to environmental anoxia and re-oxygenation in eastern oysters (Crassostrea virginica). KUROCHKIN, IO*; IVANINA, AV; EILERS, S; SOKOLOVA, IM; University of North Carolina at Charlotte, Charlotte, USA; University of North Carolina at Charlotte, Charlotte, USA; Hochschule Bremen, Bremen, Germany; University of North Carolina at Charlotte, Charlotte, USA isokolov@uncc.edu
Intertidal organisms are periodically exposed to limited oxygen availability followed by reoxygenation during tidal cycles, often in the presence of other stressors such as metal pollution, but the effects of these stressors on their metabolism are not well understood. We have studied the effects of anoxia caused by air exposure (1-6 days) with subsequent reoxygenation on mitochondrial function and nitric oxide (NO) levels in control oysters and in oysters exposed to 50 ug L-1 of cadmium (Cd) for 30 days. Oxygen consumption of isolated mitochondria respiring on pyruvate, succinate, and TMPD decreased during air exposure but increased well above the normoxic levels during the first 6h of re-oxygenation in control (not exposed to Cd) oysters. Respiratory control ratios (RCR) decreased during anoxia and recovery in control oysters indicating a decrease in mitochondrial efficiency. In Cd-exposed oysters, a decrease in mitochondrial respiration or RCR during hypoxia was not significant, and the respiration burst in first hours of reoxygenation was completely abolished. NO content was significantly decreased and remained stable after 3 days of air exposure returning to the initial levels after 6 h of normoxic recovery in control oysters. NO level recovery was significantly delayed in Cd exposed oysters during recovery what correlated with the significantly lower activity of nitric oxide synthase in Cd-exposed oysters. These data suggest that cadmium may have an important effect on mitochondrial metabolism and on metabolic adaptations to periodical anoxia and reoxygenation during the tidal cycle in marine bivalves. Supported by NSF CAREER (IBN-0347238).
