Beauvais-Flück Rebecca, Slaveykova Vera I, Cosio Claudia
Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 66, Boulevard Carl-Vogt, 1211 Genève 4, Switzerland.
Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 66, Boulevard Carl-Vogt, 1211 Genève 4, Switzerland.
Aquat Toxicol. 2018 Jan;194:103-111. doi: 10.1016/j.aquatox.2017.11.010. Epub 2017 Nov 17.
The effects of two methylmercury (CHHg, MeHg) concentrations, representative of environmental level and extreme contamination, were investigated on the macrophyte Elodea nuttallii during a 2h-exposure combining transcriptomic (RNA-Seq), physiological endpoints (pigment contents, activity of anti-oxidative stress enzymes) and bioaccumulation. Exposure to MeHg induced the up- and down-regulation of numerous genes (4389 and 16853 for 10ngL and 10μgL MeHg exposure, respectively) involved in sugar, amino acid and secondary metabolism (e.g. cinnamic acid, flavonoids) at both concentrations. Genes coding for photosynthesis, membrane integrity, metal homeostasis, water transport and anti-oxidative enzymes were additionally up- and down-regulated at the higher concentration. At the physiological level, exposure to both MeHg concentrations resulted in a strong increase of anthocyanin content in shoots. Chlorophyll content and antioxidant enzyme activities were unchanged. The data suggest that the macrophyte was able to efficiently cope with the stress resulting from MeHg exposure, possibly by using anthocyanin as anti-oxidant and S-rich amino acids (such as cysteine and methionine) as chelators. Transcriptomics analysis enabled gaining novel insights on molecular effects of MeHg in primary producers, which are one of the main entry pathway of hazardous MeHg in aquatic food webs.
在为期2小时的暴露实验中，结合转录组学（RNA测序）、生理指标（色素含量、抗氧化应激酶活性）和生物积累，研究了两种代表环境水平和极端污染的甲基汞（CHHg，MeHg）浓度对大型植物伊乐藻的影响。暴露于MeHg会导致两种浓度下参与糖、氨基酸和次生代谢（如肉桂酸、类黄酮）的大量基因上调和下调（10 ng/L和10 μg/L MeHg暴露分别为4389个和16853个）。在较高浓度下，编码光合作用、膜完整性、金属稳态、水分运输和抗氧化酶的基因也额外上调和下调。在生理水平上，暴露于两种MeHg浓度都会导致茎中花青素含量大幅增加。叶绿素含量和抗氧化酶活性未发生变化。数据表明，大型植物可能通过利用花青素作为抗氧化剂和富含硫的氨基酸（如半胱氨酸和蛋氨酸）作为螯合剂，能够有效应对MeHg暴露所产生的压力。转录组学分析有助于深入了解MeHg对初级生产者的分子影响，初级生产者是有害MeHg进入水生食物网的主要途径之一。
