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Interactive effects of cadmium and hypoxia on metabolic responses and bacterial loads of eastern oysters Crassostrea virginica Gmelin.
- Source :
-
Chemosphere [Chemosphere] 2011 Jan; Vol. 82 (3), pp. 377-89. Date of Electronic Publication: 2010 Oct 23. - Publication Year :
- 2011
-
Abstract
- Pollution by toxic metals including cadmium (Cd) and hypoxia are important stressors in estuaries and coastal waters which may interactively affect sessile benthic organisms, such as oysters. We studied metabolic responses to prolonged hypoxic acclimation (2 weeks at 5% O2) in control and Cd-exposed (30 d at 50 μg L(-1) Cd) oysters Crassostrea virginica, and analyzed the effects of these stressors on abundance of Vibrio spp. in oysters. Hypoxia-acclimated oysters retained normal standard metabolic rates (SMR) at 5% O2, in contrast to a decline of SMR observed during acute hypoxia. However, oysters spent more time actively ventilating in hypoxia than normoxia resulting in enhanced Cd uptake and 2.7-fold higher tissue Cd burdens in hypoxia. Cd exposure led to a significant decrease in tissue glycogen stores, increase in free glucose levels and elevated activity of glycolytic enzymes (hexokinase and aldolase) indicating a greater dependence on carbohydrate catabolism. A compensatory increase in activities of two key mitochondrial enzymes (citrate synthase and cytochrome c oxidase) was found during prolonged hypoxia in control oysters but suppressed in Cd-exposed ones. Cd exposure also resulted in a significant increase in abundance of Vibrio parahaemolyticus and Vibrio vulnificus levels during normoxia and hypoxia, respectively. Overall, Cd- and hypoxia-induced changes in metabolic profile, Cd accumulation and bacterial flora of oysters indicate that these stressors can synergistically impact energy homeostasis, performance and survival of oysters in polluted estuaries and have significant consequences for transfer of Cd and bacterial pathogens to the higher levels of the food chain.<br /> (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Subjects :
- Animals
Bacteria, Anaerobic growth & development
Bacterial Load
Cadmium metabolism
Crassostrea metabolism
Crassostrea microbiology
Oxygen analysis
Seawater microbiology
Water Pollutants, Chemical metabolism
Cadmium toxicity
Crassostrea drug effects
Oxygen metabolism
Seawater chemistry
Water Pollutants, Chemical toxicity
Subjects
Details
- Language :
- English
- ISSN :
- 1879-1298
- Volume :
- 82
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Chemosphere
- Publication Type :
- Academic Journal
- Accession number :
- 20971492
- Full Text :
- https://doi.org/10.1016/j.chemosphere.2010.09.075