| Polybrominated diphenyl ethers?PBDEs?are a new kind of persistent organic pollutants,with high flame retardant efficiency and good thermal stability,being widely used for electronic equipment.PBDEs which are lipophilic and easily accumulated in the vivo,be stored in the organism.BDE-47,2,2',4,4'-tetra-bromodiphenyl ether is the most widely distributed,the highest content in organism,the strongest toxicity to the human and animals in PBDEs homologues.Nereis is the dominant benthic animal which widely distribute in China's coastal intertidal zone.It has characteristics of large quantity,good stability and higher sensitivity to external stimuli.The perinereis aibuhitensis is used as biological subject in acute toxicity test,for determining the 96h-LC50.On this basis,The activities of SOD,CAT,GST,GPx and the contents of GSH,MDA of the antioxidant defense system of Perinereis aibuhitensis exposed to 2,4,8mg·L-1 of BDE-47 pollutants.And were determined SCGE method was used to observe the DNA damage.Determined HSP70 mRNA expression quantity by RT-PCR.A preliminary study of BDE-47 toxic effect on perinereis aibuhitensis is for the future development of PBDEs in the marine environment biological detections and ecological risk assessments providing a scientific basis.Conclusions are as follows:1.Acute toxicity test: 96 hours semi lethal concentration of BDE-47 to perinereis aibuhitensis is 31.24 mg·L-1.2.On 1th day,the SOD activity of the 4 mg·L-1 and 8 mg·L-1 groups significantly decreased?P<0.05?.Overall,during the period of 17 d,SOD activity of the 2 mg·L-1,4 mg·L-1groups were induced to rise.On 14 th day,SOD activity in 4 mg·L-1,8 mg·L-1 groups were significant?P<0.05?and significantly?P<0.01?inhibited respectively.In net water recovery period,the concentration of SOD and the control group,and no significant difference?P>0.05?.The MDA content of all the treatment groups were induced to increase?P<0.05?,and 4mg·L-1 group significantly increased?P<0.01?on 1th day.There was no significant change in the content of MDA of the treatment groups during the exposure period of 4th14th day,only 8mg·L-1 group was significantly higher?P<0.05?on 7th day.During the period of r5,is significantly induced?P<0.05?.3.DNA damage: Three evaluation indexes Tail lengh,tail DNA% and OTM to DNA damage,time-effect relationship changes are basically the same.Under the 1th,the 4th day differences are not significant between the experimental groups and the control group?P>0.05?,Three evaluation indexes,those are significantly increased on the seventh and fourteenth day?P<0.01?,and during the r5 recovery period reach the maximum value.4.The relative expression of mRNA of HSP70: After exposed 1th day,compared with the control group the relative expression of HSP70 mRNA there is no significant difference between the experimental groups and the control group.On the 4th day dose groups are increased relative to control group,2,4 mg·L-1 dose groups are obviously significant?P<0.05?.As the exposure time prolonged?714 day?the relative expression of mRNA of HSP70 is significantly increased?P<0.05?.In net water recovery period,2,4 mg·L-1 concentration increased continuously?P<0.05?,just 8 mg·L-1 dose group is on the downtrend.In conclusion,there are significant differences MDA content,SOD activity of the antioxidant defensesystem of Perinereis aibuhitensis between the control group and the experimental groups on the 1th day.Therefore,MDA content and SOD activity can be used as a biomarker for early warning of BDE-47 pollution.The DNA damage of BDE-47 to Perinereis aibuhitensis belongs to slight damage,Tail Length,tail DNA% and OTM changes has the obvious dose effect relationship and the time effect relationship,the three indexes can also be used as biomarkers of BDE-47 pollution.The relative expression of mRNA of HSP70 shows obvious time effect relationship and in a relatively short period of time HSP70 gene can have good sensitivity,as a result,HSP70 gene can serve as a biomarker for early warning of BDE-47 pollution. |
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