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1、ECOTOXICOLOGYEffectsofCadmiumExposureonLipidPeroxidationandtheAntioxidantSysteminFourth-InstarLarvaeofPropsilocerusakamusi(Diptera:Chironomidae)UnderlaboratoryConditions1XIANYUNZHENG,WENMINLONG,YAPINGGUO,ANDENBOMACollegeofLifeScienceandTechnology,ShanxiUniversity,Taiyuan,Shanxi0300
2、06,PeopleÕsRepublicofChinaJ.Econ.Entomol.104(3):827Ð832(2011);DOI:10.1603/EC10109ABSTRACTEnzymaticantioxidantssuchasselenium-dependentglutathioneperoxidase(GPx),glutathionetransferase(GST),glutathionereductase(GR),andsuperoxidedismutases(SOD),aswellastheconcentrationofhydrogenperox
3、ide(H2O2)andmalondialdehyde(MDA,anindicatoroflipidperoxidation)weredeterminedtoidentifywhichantioxidantenzymesparticipateintheefÞcient2scavengingofROSgenerateduponexposuretohighdosesofCdinfourth-instarPropsilocerusakamusi(Tokuna)(Diptera:Chironomidae)larvaeafter72-hexposure.Asigni
4、ÞcantincreaseinMDA2levelsandachangeinGRandGPxactivitiesintheCd-treatedP.akamusiwereobserved.TheMDAin25.0and50.0mmol/litertreatmentswassigniÞcantlyhigherthanthatofthecontroldoseafter72h2exposure.GPxactivitywassigniÞcantlyinducedbyCdexposureonlyinthe50.0-mmol/liter2treatmentwitha0
5、.59-foldincreaseinthecontrol.AlldosesofCdsigniÞcantlysuppressedGRactivitycomparedwiththeÞndingsforthecontroldose,withaninhibitedrateupto0.55-foldinthe225.0mmol/literCdtreatment.SODandGSTactivitieswerenotaltered.Theresultsindicatethat2Cdcaninduceoxidativestressasindicatedbythechan
6、gesinlipidperoxidationandantioxidantstatus.ForP.akamusi,anincreaseinthedosethatthethresholdneededfordefense(namely,MDAlevelandGPxactivity)activationwasachieved.Fromthis,organismscanbehypothesizedtoenable2cellstoavoidoxidantstressuptoacertainextentwheredamageisagainmeasurable(highe
7、rCdconcentration).2KEYWORDSPropsilocerusakamusi,Cd,antioxidantdefenses,lipidperoxidation,oxidativestressThecontaminationofwaterbytoxicheavymetalsisnogeniccompoundsaswellasROS.GSHisoneofaworldwideenvironmentalproblem.Metalsinwa-thebestknownexamplesofanonenzymaticdefenseterandsedime
8、ntshavethepotentialtocause
