Cima Francesca, Varello Roberta
Laboratory of Biology of Ascidians, Department of Biology (DiBio), University of Padova, Padova, Italy.
Front Physiol. 2023 Aug 15;14:1230943. doi: 10.3389/fphys.2023.1230943. eCollection 2023.
Edible bivalves constitute an important bioresource from an economic point of view, and studies on their immune responses to environmental pollutants are crucial for both the preservation of biodiversity and economic reasons. The worldwide diffusion of copper(I)-based antifouling paints has increased copper leaching into coastal environments and its potential impact on both target and nontarget organisms. In this study, immunotoxicity assays were carried out with short-term (60 min) cultures of hemocytes from the bivalves -a mussel dominant in the macrofouling community-and -a clam dominant in the soft-sediment community-exposed to CuCl to compare the toxic effects on their immune responses. The LC values were similar, 40 μM (3.94 mg L) for the mussel and 44 μM (4.33 mg L) for the clam. In both species, apoptosis occurred after exposure to 1 µM (98.9 μg L) CuCl, the concentration able to significantly increase the intracellular Ca content. Biomarkers of cell morphology and motility revealed microfilament disruption, a significant decrease in yeast phagocytosis and lysosome hydrolase (β-glucuronidase) inhibition beginning from 0.5 µM (49.5 μg L) CuCl in both the mussel and clam. The same concentration of CuCl affected biomarkers of oxidative stress, as a significant decrease in reduced glutathione content in the cytoplasm and inhibition of mitochondrial cytochrome-c oxidase (COX) were detected in both species. Comparison of the biomarkers showed that clam is more sensitive than the mussel regarding alterations to the lysosomal membrane and reactive oxygen species (ROS) production, which supports the potential harmful effects of antifouling biocides on the survival of nontarget pivotal species in the coastal community.
从经济角度来看，可食用双壳贝类是一种重要的生物资源，研究它们对环境污染物的免疫反应对于生物多样性保护和经济发展都至关重要。基于铜（I）的防污涂料在全球范围内的广泛使用，增加了铜向沿海环境中的浸出及其对目标和非目标生物的潜在影响。在本研究中，对双壳贝类（在大型污损群落中占主导地位的贻贝和在软沉积物群落中占主导地位的蛤）的血细胞进行了短期（60分钟）培养，并使其暴露于氯化铜中，以进行免疫毒性测定，比较其对免疫反应的毒性作用。半数致死浓度值相似，贻贝为40μM（3.94mg/L），蛤为44μM（4.33mg/L）。在这两个物种中，暴露于1μM（98.9μg/L）氯化铜后均发生凋亡，该浓度能够显著增加细胞内钙含量。细胞形态和运动性的生物标志物显示，从0.5μM（49.5μg/L）氯化铜开始，贻贝和蛤的微丝均出现破坏，酵母吞噬作用显著降低，溶酶体水解酶（β-葡萄糖醛酸酶）受到抑制。相同浓度的氯化铜影响氧化应激生物标志物，在这两个物种中均检测到细胞质中还原型谷胱甘肽含量显著降低以及线粒体细胞色素c氧化酶（COX）受到抑制。生物标志物的比较表明，在溶酶体膜改变和活性氧（ROS）产生方面，蛤比贻贝更敏感，这支持了防污杀菌剂对沿海群落中非目标关键物种生存的潜在有害影响。
