Dipartimento di Scienze della Vita e dell'Ambiente (DiSVA), Università Politecnica delle Marche, Ancona, Italy.
Department of Environmental Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
Mar Environ Res. 2020 Dec;162:105091. doi: 10.1016/j.marenvres.2020.105091. Epub 2020 Jul 29.
Anthropogenic inputs of carbon dioxide in the atmosphere are driving ocean warming and acidification. The potential threat represented by these changes for marine species could be amplified in coastal areas, characterized by higher levels of pollutants. In addition, temperate organisms may exhibit a different seasonal tolerance to stressors influenced by fluctuations of environmental and physiological factors. In this study, Mediterranean mussels Mytilus galloprovincialis collected both in summer and winter were exposed to combinations of two temperatures (SST, seasonal surface temperature and SST+5 °C) and two levels of pH (8.20 and 7.40) in clean or cadmium contaminated seawater (20 μg/L Cd). mRNA levels of genes related to metal-induced stress response were investigated, including metallothionein mt-20, heat-shock protein hsp70, superoxide dismutase Cu/Zn-sod, catalase cat, glutathione peroxidase gpx1 and glutathione S-transferase gst-pi. To further elucidate if tissues with different physiological roles could exhibit different responsiveness, such analyses were carried out in digestive gland and in gills of exposed mussels. mt-20 mRNA increase after Cd-exposure was higher in the digestive gland than in the gills, with few modulations by temperature or pH only in the latter. Acidification, alone or in combination with other stressors, increased hsp70 mRNA, with seasonal- and tissue-specificities (higher in summer and in digestive gland). Among antioxidants, gpx1 mRNA was affected by Cd in both tissues and seasons, with further modulations due to pH and temperature variation tissue- and season-specific; in winter the combination of Cd, warming and acidification affected Cu/Zn-sod both in digestive gland and gills and cat only in gills, while weak seasonal variations were observed for gst-pi transcripts only in digestive gland. The overall results highlighted the importance of considering seasonality and responsiveness of different tissues to predict the effects of sudden changes in environmental parameters on responsiveness to and toxicity of chemicals in marine coastal organisms.
大气中二氧化碳的人为输入正在推动海洋变暖酸化。这些变化对海洋物种构成的潜在威胁在污染水平较高的沿海地区可能会加剧。此外，温带生物可能会表现出不同的季节性应激耐受能力，这受环境和生理因素波动的影响。在这项研究中，采集了夏季和冬季的南方贻贝 Mytilus galloprovincialis，分别在清洁或镉污染海水（20μg/L Cd）中暴露于两种温度（SST，季节性表面温度和 SST+5°C）和两种 pH 值（8.20 和 7.40）的组合下。研究了与金属诱导应激反应相关的基因的 mRNA 水平，包括金属硫蛋白 mt-20、热休克蛋白 hsp70、超氧化物歧化酶 Cu/Zn-sod、过氧化氢酶 cat、谷胱甘肽过氧化物酶 gpx1 和谷胱甘肽 S-转移酶 gst-pi。为了进一步阐明是否具有不同生理功能的组织可能表现出不同的反应性，在暴露贻贝的消化腺和鳃中进行了此类分析。在镉暴露后，消化腺中 mt-20 mRNA 的增加高于鳃，仅在后者中存在由温度或 pH 值引起的少数调节。酸化单独或与其他胁迫因素一起，增加了 hsp70 mRNA，具有季节性和组织特异性（夏季和消化腺中更高）。在抗氧化剂中，gpx1 mRNA 在两种组织和季节中均受 Cd 影响，并且由于 pH 值和温度变化，其在组织和季节中进一步调节；在冬季，Cd、变暖酸化的组合影响了消化腺和鳃中的 Cu/Zn-sod 和 gills 中的 cat，而 gst-pi 转录物仅在消化腺中观察到微弱的季节性变化。总的来说，这些结果强调了考虑季节性和不同组织的反应性的重要性，以预测环境参数的突然变化对海洋沿海生物对化学物质的反应性和毒性的影响。
