Génétique Moléculaire, Génomique et Microbiologie, Département Micro-organismes, Génomes, Environnement, UMR7156 Université de Strasbourg/CNRS, Strasbourg, France.
Commissariat à l'Energie Atomique (CEA), Institut de Génomique (IG), Evry, France.
Environ Microbiol. 2015 Jun;17(6):1941-9. doi: 10.1111/1462-2920.12474. Epub 2014 Apr 28.
Arsenic is a toxic metalloid known to cause multiple and severe cellular damages, including lipid peroxidation, protein misfolding, mutagenesis and double and single-stranded DNA breaks. Thus, exposure to this compound is lethal for most organisms but some species such as the photosynthetic protist Euglena mutabilis are able to cope with very high concentrations of this metalloid. Our comparative transcriptomic approaches performed on both an arsenic hypertolerant protist, i.e. E. mutabilis, and a more sensitive one, i.e. E. gracilis, revealed multiple mechanisms involved in arsenic tolerance. Indeed, E. mutabilis prevents efficiently the accumulation of arsenic in the cell through the expression of several transporters. More surprisingly, this protist induced the expression of active DNA reparation and protein turnover mechanisms, which allow E. mutabilis to maintain functional integrity of the cell under challenging conditions. Our observations suggest that this protist has acquired specific functions regarding arsenic and has developed an original metabolism to cope with acid mine drainages-related stresses.
砷是一种有毒的类金属，已知会导致多种严重的细胞损伤，包括脂质过氧化、蛋白质错误折叠、突变和双链及单链 DNA 断裂。因此，大多数生物体暴露于这种化合物是致命的，但有些物种，如光合作用的原生生物眼虫属可在非常高浓度的这种类金属下生存。我们对一种砷超耐受原生生物，即眼虫属，和一种更敏感的原生生物，即眼虫属，进行的比较转录组学方法揭示了多种与砷耐受相关的机制。事实上，眼虫属通过表达几种转运蛋白有效地防止砷在细胞内积累。更令人惊讶的是，这种原生生物诱导了活性 DNA 修复和蛋白质周转机制的表达，使眼虫属能够在挑战性条件下维持细胞的功能完整性。我们的观察结果表明，这种原生生物已经获得了与砷有关的特定功能，并发展了一种独特的代谢来应对与酸性矿山排水有关的压力。
