Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for environmental and aquatic sciences, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 66, boulevard Carl-Vogt, 1211, Geneva 4, Switzerland.
Sci Rep. 2017 Aug 14;7(1):8034. doi: 10.1038/s41598-017-08515-8.
Contamination by mercury (Hg) is a worldwide concern because of Hg toxicity and biomagnification in aquatic food webs. Nevertheless, bioavailability and cellular toxicity pathways of inorganic (IHg) and methyl-Hg (MeHg) remain poorly understood. We analyzed the uptake, transcriptomic, and physiological responses in the microalga Chlamydomonas reinhardtii exposed to IHg or MeHg. Bioavailability of MeHg was up to 27× higher than for IHg. Genes involved in cell processes, energy metabolism and transport were dysregulated by both Hg species. Physiological analysis revealed an impact on photosynthesis and reduction-oxidation reaction metabolism. Nevertheless, MeHg dysregulated a larger number of genes and with a stronger fold-change than IHg at equivalent intracellular concentration. Analysis of the perturbations of the cell's functions helped to derive a detailed mechanistic understanding of differences in cellular handling of IHg and MeHg resulting in MeHg having a stronger impact. This knowledge is central for the prediction of impact of toxicants on organisms.
汞（Hg）污染是一个全球性的问题，因为汞在水生食物网中具有毒性和生物放大作用。然而，无机汞（IHg）和甲基汞（MeHg）的生物利用度和细胞毒性途径仍知之甚少。我们分析了暴露于 IHg 或 MeHg 的绿藻莱茵衣藻的吸收、转录组和生理反应。MeHg 的生物利用度比 IHg 高 27 倍。Hg 两种物质都使参与细胞过程、能量代谢和运输的基因失调。生理分析显示对光合作用和氧化还原反应代谢有影响。然而，在等效的细胞内浓度下，MeHg 使更多的基因失调，且变化幅度比 IHg 更大。对细胞功能的干扰分析有助于深入了解 IHg 和 MeHg 在细胞处理方面的差异，从而导致 MeHg 产生更强的影响。这些知识对于预测有毒物质对生物体的影响至关重要。
