Interactive effects of copper exposure and environmental hypercapnia on immune functions of marine bivalves Crassostrea virginica and Mercenaria mercenaria
Interactive effects of copper exposure and environmental hypercapnia on immune functions of marine bivalves Crassostrea virginica and Mercenaria mercenaria
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DOI：
10.1016/j.fsi.2015.12.011
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发表时间：
2016-02-01
影响因子：
4.7
通讯作者：
Sokolova, Inna M.
中科院分区：
文献类型：
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作者：
Ivanina, Anna V.;Hawkins, Chelsea;Sokolova, Inna M.
双壳类等河口生物通常在其栖息地接触铜 (Cu) 等微量金属和高碳酸血症（二氧化碳水平升高），这可能会影响其生理和免疫功能。本研究调查了升高的CO2水平（类似于800-2000 mu atm P-CO2，如全球气候变化的近期情景所预测的）和Cu（50 mu g l(-1)）对居住在沉积物中的硬蛤Mercenaria Mercenaria和表层双壳类东部牡蛎Crassostrea virginica免疫功能的综合影响。将蛤和牡蛎暴露于不同的 CO2 和 Cu 水平下 4 周，并评估组织 Cu 负荷和免疫参数，以检验以下假设：由于游离 Cu2+ 的生物利用度较高，高碳酸血症会增强 Cu 的吸收，并增加 Cu 的免疫调节作用。接触铜会刺激蛤和牡蛎的关键免疫参数，导致循环血细胞数量增加、血细胞吞噬作用和粘附能力增强，以及血淋巴抗寄生虫和抗菌特性增强，这反映在溶菌酶和半胱氨酸蛋白酶抑制剂的活性更高。 Cu 暴露引起的溶菌酶激活在正常碳酸血症（类似于 400 mu atm P-CO2）中最显着，蛋白酶抑制剂水平的增加在高碳酸血症（类似于 800-2000 mu atm P-CO2）中最强，但 Cu 的其他免疫刺激作用在所有 P-CO2 暴露中都很明显。蛤和牡蛎的血细胞的代谢活动（以常规和线粒体耗氧率测量）受到铜暴露的抑制，这可能反映了 ATP 合成和/或周转率较低。然而，这种代谢抑制对所研究的血细胞免疫功能（例如吞噬作用或粘附能力）没有负面影响。高碳酸血症（类似于 800-2000 mu atm P-CO2）轻微但显着地增加了血细胞中 Cu 的积累，与 CO2 酸化水中较高的 Cu2+ 生物利用度一致，但对蛤和牡蛎的细胞和体液免疫特性影响不大。这些发现表明，低水平的铜污染可能会增强河口双壳类动物的免疫力，而中度高碳酸血症（例如根据全球气候变化的近期情景所预测的）不会强烈影响其免疫参数。 (C) 2015 Elsevier Ltd. 保留所有权利。
Estuarine organisms such as bivalves are commonly exposed to trace metals such as copper (Cu) and hypercapnia (elevated CO2 levels) in their habitats, which may affect their physiology and immune function. This study investigated the combined effects of elevated CO2 levels (similar to 800-2000 mu atm P-CO2, such as predicted by the near-future scenarios of global climate change) and Cu (50 mu g l(-1)) on immune functions of the sediment dwelling hard clams Mercenaria mercenaria and an epifaunal bivalve, the eastern oyster Crassostrea virginica. Clams and oysters were exposed for 4 weeks to different CO2 and Cu levels, and tissue Cu burdens and immune parameters were assessed to test the hypothesis that hypercapnia will enhance Cu uptake due to the higher bioavailability of free Cu2+ and increase the immunomodulatory effects of Cu. Exposure to Cu stimulated key immune parameters of clams and oysters leading to increased number of circulating hemocytes, higher phagocytosis and adhesion ability of hemocytes, as well as enhanced antiparasitic and antibacterial properties of the hemolymph reflected in higher activities of lysozyme and inhibitors of cysteine proteases. Lysozyme activation by Cu exposure was most prominent in normocapnia (similar to 400 mu atm P-CO2) and an increase in the levels of the protease inhibitors was strongest in hypercapnia (similar to 800-2000 mu atm P-CO2), but other immunostimulatory effects of Cu were evident in all P-CO2 exposures. Metabolic activity of hemocytes of clams and oysters (measured as routine and mitochondrial oxygen consumption rates) was suppressed by Cu exposure likely reflecting lower rates of ATP synthesis and/or turnover. However, this metabolic suppression had no negative effects of the studied immune functions of hemocytes such as phagocytosis or adhesion capacity. Hypercapnia (similar to 800-2000 mu atm P-CO2) slightly but significantly enhanced accumulation of Cu in hemocytes, consistent with higher Cu2+ bioavailability in CO2-acidified water, but had little effect on cellular and humoral immune traits of clams and oysters. These findings indicate that low levels of Cu contamination may enhance immunity of estuarine bivalves while moderate hypercapnia (such as predicted by the near future scenarios of the global climate change) does not strongly affect their immune parameters. (C) 2015 Elsevier Ltd. All rights reserved.