کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6382457 | 1625956 | 2014 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Interactive effects of CO2 and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم آبزیان
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چکیده انگلیسی
Increased anthropogenic emission of CO2 changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO2 and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves-Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4-5 weeks to clean seawater (control) and to either 50 μg Lâ1 Cu or 50 μg Lâ1 Cd at one of three partial pressures of CO2 (PCO2 â¼395, â¼800 and â¼1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated PCO2 enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated PCO2, but PCO2 modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome at all CO2 levels. In contrast, trypsin- and caspase-like activities of the oyster proteasome were slightly inhibited by Cd exposure in normocapnia but this inhibition was reversed at elevated PCO2. Cu exposure inhibited the chymotrypsin-like activity of the oyster proteasome regardless of the exposure PCO2. The effects of metal exposure on the proteasome activity were less pronounced in clams, likely due to the lower metal accumulation. However, the general trends (i.e. an increase during Cd exposure, inhibition during exposure to Cu, and overall stimulatory effects of elevated PCO2) were similar to those found in oysters. Levels of mRNA for ubiquitin and tumor suppressor p53 were suppressed by metal exposures in normocapnia in both species but this effect was alleviated or reversed at elevated PCO2. Cellular energy status of oysters was maintained at all metal and CO2 exposures, while in clams the simultaneous exposure to Cu and moderate hypercapnia (â¼800 μatm PCO2) led to a decline in glycogen, ATP and ADP levels and an increase in AMP indicating energy deficiency. These data suggest that environmental CO2 levels can modulate accumulation and physiological effects of metals in bivalves in a species-specific manner which can affect their fitness and survival during the global change in estuaries.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Aquatic Toxicology - Volume 149, April 2014, Pages 65-82
Journal: Aquatic Toxicology - Volume 149, April 2014, Pages 65-82
نویسندگان
Sandra Götze, Omera B. Matoo, Elia Beniash, Reinhard Saborowski, Inna M. Sokolova,