Dupraz Valentin, Coquillé Nathalie, Ménard Dominique, Sussarellu Rossana, Haugarreau Larissa, Stachowski-Haberkorn Sabine
Ifremer, Laboratoire d'Écotoxicologie, rue de l'île d'Yeu, BP 21105, F-44311 Nantes Cedex 03, France.
Ifremer, Laboratoire d'Écotoxicologie, rue de l'île d'Yeu, BP 21105, F-44311 Nantes Cedex 03, France; Irstea, UR EABX, Centre de Bordeaux, 50 avenue de Verdun, F-33612 Cestas Cedex, France; Université de Bordeaux, UMR 5805, EPOC, Laboratoire de Physico Toxico Chimie de l'environnement, 351 Cours de la Libération, CS 10004, F-33405 Talence Cedex, France; CNRS, UMR 5805, EPOC, Laboratoire de Physico Toxico Chimie de l'environnement, 351 Cours de la Libération, CS 10004, F-33405 Talence Cedex, France.
Chemosphere. 2016 May;151:241-52. doi: 10.1016/j.chemosphere.2016.02.073. Epub 2016 Mar 15.
A wild strain of Chaetoceros calcitrans and wild and diuron-resistant strains of Tetraselmis suecica, were exposed to the PSII inhibitor herbicides diuron and irgarol, individually and in mixtures. The effects of three concentrations of diuron and irgarol and four binary mixtures were evaluated on doubling time, relative reactive oxygen species and lipid content by flow cytometry, and on photosynthetic efficiency by pulse amplitude modulated fluorescence. In both wild strains, significant effects were observed for each molecule at the highest concentration tested: at irgarol 0.5 μg L(-1), C. calcitrans was shown to be more sensitive than T. suecica (+52% and +19% in doubling time, respectively), whereas at diuron 5 μg L(-1), T. suecica was more affected (+125% in doubling time) than C. calcitrans (+21%). Overall, irgarol had a higher toxicity at a lower concentration than diuron (no effect at diuron 0.5 μg L(-1)) for both wild strains. The strongest mixture (irgarol 0.5 μg L(-1) + diuron 5 μg L(-1)) increased doubling time by 356% for T. suecica, thus showing amplified effects when the two compounds were mixed. Sequencing of the diuron-resistant strain demonstrated a single mutation in the psbA gene coding sequence. Although resistance of this strain to diuron was confirmed with no effect at the highest diuron concentration, no resistance to irgarol was shown. In addition, the mutant strain exposed to the strongest mixture showed a 3.5-fold increase in doubling time compared with irgarol alone, thereby supporting the hypothesis of a biochemical interaction between these two compounds.
将野生型角毛藻（Chaetoceros calcitrans）以及野生型和耐敌草隆的瑞典四爿藻（Tetraselmis suecica）菌株分别单独以及混合暴露于PSII抑制剂除草剂敌草隆和异菌脲中。通过流式细胞术评估了三种浓度的敌草隆和异菌脲以及四种二元混合物对加倍时间、相对活性氧物种和脂质含量的影响，并通过脉冲幅度调制荧光评估了对光合效率的影响。在两种野生菌株中，在测试的最高浓度下，每种分子都观察到了显著影响：在异菌脲浓度为0.5 μg L⁻¹时，角毛藻比瑞典四爿藻更敏感（加倍时间分别增加52%和19%），而在敌草隆浓度为5 μg L⁻¹时，瑞典四爿藻比角毛藻受影响更大（加倍时间增加125%），而角毛藻仅增加21%。总体而言，对于两种野生菌株，异菌脲在较低浓度下的毒性高于敌草隆（敌草隆浓度为0.5 μg L⁻¹时无影响）。最强的混合物（异菌脲0.5 μg L⁻¹ + 敌草隆5 μg L⁻¹）使瑞典四爿藻的加倍时间增加了356%，因此表明两种化合物混合时会产生放大效应。耐敌草隆菌株的测序表明，编码psbA基因的序列存在单个突变。尽管该菌株对最高浓度敌草隆的抗性得到了证实，即无影响，但对异菌脲未表现出抗性。此外，与单独使用异菌脲相比，暴露于最强混合物中的突变菌株的加倍时间增加了3.5倍，从而支持了这两种化合物之间存在生化相互作用的假设。
