摘要:
以羊角月牙藻(Selenastrum capricornutum)为实验材料,研究了三氯生(triclosan,TCS)对羊角月牙藻生长、光合作用叶绿素荧光动力学参数及抗氧化酶活性的影响。结果表明,TCS对羊角月牙藻的96 h-EC50为0.112 mg·L-1,属于高毒。TCS暴露对羊角月牙藻的叶绿素荧光中ABS/RC、PIabs、RC/CSo和OEC比例等参数有显著影响。随着三氯生浓度的增大,羊角月牙藻的叶绿素荧光中ABS/RC大幅上升,PIabs、RC/CSo和OEC比例下降;当三氯生浓度为0.256 mg·L-1时,ABS/RC达到最大值,PIabs、RC/CSo和OEC比例下降为最小值,表明藻细胞光合作用的原初反应及电子链传递过程受到严重阻碍。同时,三氯生对羊角月牙藻体内抗氧化酶系中GST活性和MDA含量也有较大影响。在低浓度暴露下,GST活性随TCS浓度增加而增大,但当TCS浓度超过0.256 mg·L-1时,GST活性出现显著下降,同时MDA含量达到最大,这种GST活性的下降同时伴随MDA含量的增加表明藻细胞膜系统受到较大损害。
Abstract:
The toxic effects of triclosan on microalgae (Selenastrum capricornutum) were investigated by the growth inhibition test, photosystemⅡfluorescence performance, and a battery of biochemical parameters such as GST, CAT enzymes activities and GSH and MDA contents in this study. The results showed that 96 h-EC50 of TCS for Selenastrum capricornutum was 0.112 mg·L-1, indicating that TCS was high-toxic to Selenastrum capricornutum. Sensitive responses were found in JIP-test parameters of photosynthesis including ABS/RC, PIabs, RC/CSo and ration of OEC to the exposure of TCS. With the increase of TCS concentration, ABS/RC rose substantially, while PIabs, RC/CSo and ration of OEC decreased, suggesting that the photosynthetic electron transport chain procedure and photosynthetic primary reaction were disturbed. The activities of glutathione -s-transferase (GST) and the content of methane dicarboxylic aldehyde (MDA) were affected significantly by exposure of TCS. With the further increase of TCS concentration (> 0.256 mg·L-1), the activity of GST increased initially, then decreased significantly, and the content of MDA increased continuously. It is indicated that algae cell membrane system was injured heavily under the exposure of high concentration TCS.
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