2,2’,4,4’-四溴联苯醚(BDE-47)对米氏凯伦藻的毒性效应

Toxic effect of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) on Karenia mikimotoi in the different levels of biological organizations

实验生态条件下从种群、细胞和亚细胞等不同生物组织层次上研究了一种新型持久性有机污染物—低溴代的多溴联苯醚—2,2’,4,4’-四溴联苯醚(BDE-47)对海洋赤潮微藻—米氏凯伦藻(Karenia mikimotoi)的急性和亚急性毒性效应。结果发现:(1)当BDE-47大于等于0.009 mg/L时,米氏凯伦藻的种群增长已经受到抑制,因此BDE-47对米氏凯伦藻种群增长有显著的急性毒性胁迫作用,96 h半数效应浓度(96 h-EC50)为0.219 mg/L。(2)在0.250 mg/L BDE-47的亚急性毒性胁迫下,米氏凯伦藻谷胱甘肽过氧化物酶(GPx)活性随着时间呈现先诱导升高后明显抑制的现象(P<0.05);谷胱甘肽硫转移酶(GST)和谷胱甘肽还原酶(GR)活性逐渐降低(P<0.05),还原型谷胱甘肽(GSH)含量逐渐降低(P<0.05)。基于双变量Pearson相关性分析发现,GR是较为灵敏的一种生化标志物。(3)透射电镜(TEM)的检测结果表明,与对照组相比,经过18d、0.250 mg/L BDE-47胁迫的米氏凯伦藻细胞膨胀,胞内基质出现许多高电子密度区域及大的透明空泡,线粒体和叶绿体等细胞器受到明显破坏作用。因此,BDE-47在不同组织层次上对米氏凯伦藻产生了急性毒性和亚急性毒性作用,这为全面了解BDE-47毒性以及其规范使用和正确处理提供理论支持和决策参考。

In this study,the toxic effect of 2,2＇,4,4＇-tetrabromodiphenyl ether（BDE-47） on Karenia mikimotoi was investigated based on the diverse levels of organization.The results was as follows：（1） The population growth of K.mikimotoi was significantly inhibited as the concentration of BDE-47 was more than 0.009 mg/L in the acute toxic test and the value of 96 h-EC50 was 0.219 mg/L.（2） The activity of glutathione peroxidase（GPx） increased up to the maximum with the time,and then fell to 44% of control groups＇ remarkably after 10 d（P0.05）;however,both gultathione S transferases（GST） and glutathione reductase（GR） activity slowed down gradually（P0.05） when exposed to 0.250 mg/L BDE-47 during 20 d experimental period.Morever,the level of glutathione（GSH） within the microalgae descended all the time.Of all components,the activity of GR was so sensitive to be a good biomarker to BDE-47 based on Pearson correlation analysis.（3） The cell became swelled,and there were many blank spaces and high electron dense zones in the cytoplasm compared with the control group with the exposure of 0.250 mg/L BDE-47 during 18 d according to the transmission electron microscope.Of all the organelles,the structure of mitochondria and chloroplast were most severely damaged.Hence,BDE-47 imposed pressure to K.mikimotoi in different organizational levels,but the mechanism needed to be further explored.It suggests that the usage and disposal of BDE-47 should be cautious.