Monnet Fabien, Bordas François, Deluchat Véronique, Baudu Michel
Laboratoire des sciences de l'eau et de l'environnement, Faculté des sciences, Université de Limoges, 123 Avenue Albert Thomas, 87000 Limoges, France.
Chemosphere. 2006 Dec;65(10):1806-13. doi: 10.1016/j.chemosphere.2006.04.022. Epub 2006 May 30.
The aim of this study was to investigate the toxicity of copper on the aquatic lichen Dermatocarpon luridum focusing on the activities of some antioxidant enzymes. Investigations were conducted using increasing copper concentrations (0.00, 0.25, 0.50, 0.75 and 1.00 mM CuSO(4) x 5H(2)O) in synthetic freshwater that emulated the major ion compositions of its natural water biota; time course measurement was 0, 3, 6, 12, 24 and 48 h. The copper concentration in thalli increased with its increase in the medium and the duration of treatment. Copper induced lipid peroxidation, measured using the hydroperoxi-conjugated dienes (HPCD) concentration. The decrease in the protein concentrations was similar in thalli exposed to copper concentrations above 0.50 mM and the decrease was twice lower in thalli exposed to 0.25 mM copper. The activities of antioxidant enzymes measured were differently affected by copper excess. For 0.25 mM copper, the activities of SOD (superoxide dismutase) and APX (ascorbate peroxidase) were unchanged when compared with unstressed thalli whereas the CAT (catalase) activity increased and the GR (glutathione reductase) activity decreased. The activities of SOD and APX increased in thalli exposed to concentrations above 0.50mM copper. The CAT activity increased after the first 3h of experiments at these concentrations and then decreased with the duration of treatment at an activity lower than in the unstressed plant. Whereas the APX activity increased, the GR activity similarly decreased for the copper concentration tested whatever the duration of the experiment.
本研究旨在调查铜对水生地衣Dermatocarpon luridum的毒性，重点关注一些抗氧化酶的活性。研究采用在模拟其天然水生生物群主要离子组成的合成淡水中增加铜浓度（0.00、0.25、0.50、0.75和1.00 mM CuSO₄·5H₂O）的方法进行；时间进程测量为0、3、6、12、24和48小时。地衣体中的铜浓度随培养基中铜浓度的增加和处理时间的延长而增加。铜诱导脂质过氧化，通过氢过氧化物共轭二烯（HPCD）浓度来测量。暴露于铜浓度高于0.50 mM的地衣体中蛋白质浓度的降低情况相似，而暴露于0.25 mM铜的地衣体中蛋白质浓度的降低幅度低两倍。所测量的抗氧化酶活性受铜过量的影响各不相同。对于0.25 mM铜，与未受胁迫的地衣体相比，超氧化物歧化酶（SOD）和抗坏血酸过氧化物酶（APX）的活性没有变化，而过氧化氢酶（CAT）活性增加，谷胱甘肽还原酶（GR）活性降低。暴露于铜浓度高于0.50 mM的地衣体中SOD和APX的活性增加。在这些浓度下，实验开始3小时后CAT活性增加，然后随着处理时间的延长而降低，其活性低于未受胁迫的植物。无论实验持续时间如何，对于所测试的铜浓度，APX活性增加，GR活性同样降低。
