Boukadida Khouloud, Cachot Jérôme, Clérandeaux Christelle, Gourves Pierre-Yves, Banni Mohamed
Laboratory of Biochemistry and Environmental Toxicology, ISA, Chott-Mariem, 4042, Sousse, Tunisia; University Bordeaux I, Laboratory of Oceanic and Continental Environments and Paleoenvironments, EPOC, UMR 5805, F-33400, Talence, France.
University Bordeaux I, Laboratory of Oceanic and Continental Environments and Paleoenvironments, EPOC, UMR 5805, F-33400, Talence, France.
Ecotoxicol Environ Saf. 2017 Apr;138:105-112. doi: 10.1016/j.ecoenv.2016.12.021. Epub 2016 Dec 27.
The present study aims to elucidate the stress response of early life stages of Mytilus galloprovincialis to the combine effects of selected metals and elevated temperature. For this purpose, we investigated the response of a large panel of oxidative stress markers such as catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST) activities and lipid peroxidation (thiobarbituric acid reactive substrates (TBARS) concentration) and metallothionein accumulation (MT) as well as selected gene transcription level and metal accumulation in mussels larvae exposed to a sub-lethal concentration of Cu (9.54µg/L), Ag (2.55µg/L) and mixture of the two metals (Cu (6.67µg/L)+Ag (1.47µg/L)) along with a temperature gradient (18, 20 and 22°C) for 48h. Cu and Ag applied as single or mixture were differentially accumulated in mussel larvae according to the exposure temperature. Sod, cat, gst and mt-10 gene transcription levels showed an important increase in larvae exposed to Cu, Ag or to the mix compared to the control condition at 18°C. The same pattern but with higher induction levels was recorded in larvae co-exposed to metals at 20°C. At 22°C, a significant decrease in mRNA abundance of cat, gst and sod and a significant up-regulation of mts targets (mt10 and mt20) were observed.
suggest that co-exposure to metals and moderate elevated temperature (20 and 22°C) significantly increased the antioxidant enzyme activities of catalase (CAT), and glutathione-S-transferase (GST) and caused an increase of metal and metallothionein concentrations. In contrast, no significant change in lipid peroxidation products measured as TBARS content was observed indicating a protective response of anti-oxidative system. This study provides first evidences of the early and efficient protective response of antioxidant defense mechanisms in mussel's early life stages facing in multi stressors situations.
本研究旨在阐明地中海贻贝早期生命阶段对选定金属和升高温度的联合作用的应激反应。为此，我们研究了一大组氧化应激标志物的反应，如过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、谷胱甘肽-S-转移酶（GST）活性和脂质过氧化（硫代巴比妥酸反应性底物（TBARS）浓度）以及金属硫蛋白积累（MT），以及暴露于亚致死浓度的铜（9.54μg/L）、银（2.55μg/L）和两种金属混合物（铜（6.67μg/L）+银（1.47μg/L））并伴有温度梯度（18、20和22°C）48小时的贻贝幼虫中选定基因的转录水平和金属积累情况。单独或混合施用的铜和银根据暴露温度在贻贝幼虫中差异积累。与18°C的对照条件相比，暴露于铜、银或混合物中的幼虫中Sod、cat、gst和mt-10基因转录水平显著增加。在20°C下共同暴露于金属的幼虫中记录到相同的模式，但诱导水平更高。在22°C时，观察到cat、gst和sod的mRNA丰度显著下降，mts靶标（mt10和mt20）显著上调。
表明共同暴露于金属和适度升高的温度（20和22°C）显著增加了过氧化氢酶（CAT）和谷胱甘肽-S-转移酶（GST）的抗氧化酶活性，并导致金属和金属硫蛋白浓度增加。相比之下，以TBARS含量衡量的脂质过氧化产物没有显著变化，表明抗氧化系统有保护反应。本研究首次提供了贻贝早期生命阶段抗氧化防御机制在面对多应激源情况时早期有效保护反应的证据。
