壬基酚对波纹巴非蛤(Paphia undulata)内脏团毒性效应

采用半静态毒性实验方法测定了壬基酚(NP)对波纹巴非蛤(Paphiaundulata)的96-hLC50值,同时研究了低、中、高3个浓度(1、10和25μg·L-1)NP胁迫下以及胁迫解除后波纹巴非蛤内脏团中超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、过氧化物酶(POD)以及丙二醛(MDA)含量的变化趋势。急性毒性实验结果表明,NP对波纹巴非蛤的96-hLC50值为260μg·L-1。胁迫初期,低、中浓度组的SOD活性被极显著抑制(P<0.01),而POD活性则被极显著诱导(P<0.01),表现为典型的"毒性兴奋效应"。胁迫过程中,低、中浓度组波纹巴非蛤内脏团的SOD活性和GSH含量呈先下降后上升的趋势,而POD活性和MDA含量则呈先上升后下降的趋势;高浓度组SOD活性呈先抑制后诱导的趋势,POD活性和MDA含量呈先下降后升高再降低的趋势,而GSH含量则一直显著高于对照组。GSH和MDA含量在整个胁迫期间均出现剧烈的波动,且浓度越高其变化程度越大。胁迫解除后,低、中浓度组的各种指标逐渐恢复到对照组水平,但高浓度组与对照组仍存在着极显著差异。上述结果表明,NP对波纹巴非蛤内脏团的抗氧化酶系统造成较为明显的影响,而波纹巴非蛤则对一定程度的NP胁迫所带来的氧化损伤具有自我修复的能力,但对高浓度NP胁迫所造成的脂质过氧化损伤短期内却无法消除。

Toxic effect of nonylphenol on Paphia undulata visceral mass

A semi-static toxicity test was conducted to determine the 96-h median lethal concentration(96-h LC50 value) of nonylphenol(NP) to Paphia undulata.In the meantime,the variations of superoxide dismutase(SOD),glutathione(GSH),and peroxidase(POD) activities and malondialdehyde(MDA) content in the visceral mass of P.undulata were studied when exposed to different concentrations NP(low:1 μg·L-1;medium:10 μg·L-1;and high:25 μg·L-1) and during the recovery stage in clear sea water.The 96-h LC50 value was 260 μg·L-1.At the early stage of stress,the SOD activity in the visceral mass of P.undulata exposed to low and medium NP concentration was inhibited(P<0.01) while the POD activity was induced(P<0.01),showing the typical "excitotoxicity effect".During the stress period,the SOD activity and GSH content in the visceral mass at low and medium NP concentrations increased after an initial decrease,while the POD activity and MDA content were in adverse.When exposed to high NP concentration,the SOD activity was inhibited first and induced then,the POD activity and MDA content increased after an initial decrease,while the GSH content was significantly higher than that of the control level in whole exposure time.The GSH and MDA contents in whole exposure time appeared sharp fluctuation,and the variation increased with increasing NP concentration.During recovery period,all the test indices in the visceral mass of P.undulata exposed to low and medium NP concentration recovered gradually to the normal level,but,for the P.undulata exposed to high NP concentration,these indices remained significant difference,as compared to the control group.The above results indicated that NP had obvious impact on the antioxidant system in the visceral mass of P.undulata,while P.undulata had self-repairing ability for the oxidative damage caused by certain degree of NP stress,but,at high NP concentration,the lipid peroxidation damage could not recover to the level of the control group in a short time.