Toxic Effects Of Triazophos On Penaeus Monodon And Two Bivalves

In this study, semi-static test methods are used to study the toxic effects oftriazophos onPenaeus monodon, Gafrarium tumidum and Perna viridis. The P.monodon toxicity studies have obtained96hLC₅₀. Antioxidant index and geneexpression patterns of P. monodon were investigated after treated by differentconcentrations of OP. In addition, pathological damageof P. monodoncaused by OPwas also studied by paraffin sections.The96hLC₅₀of OP acting on P. monodon was5.8641μg·L^-1. Many indicators of P.monodonwere measured after long-term OP exposure.The results showed that:（1）AChE activity was significantly inhibited. Comparing with the control group,therewas significant difference after7days recovery in clean seawater.（2） Indicators of P.monodonwere significantly inhibited or induced. SOD activities weresignificantlyinhibitedinhepatopancreas, muscle andserum,but obviously induced ingills.GPxactivitiesin hepatopancreas, gill, muscle and serum were also significantlyenhanced by OP. The content of MDA in hepatopancreas and gillsincreased, but keptconstant in muscle. T-AOC of P. monodonwasalso significantly inhibited or induced.After7d recovery in clean water, the antioxidant index recovered somewhat to normallevels.（3） Caspase, HSP90, EF-2, Prxand ADRPgene expression were significantlyinhibited or induced. Caspase gene expression was induced. EF-2gene expressionwas also induced.HSP90gene expression in hepatopancreas, gills and serum wereinhibited early. In hepatopancreas, the expression peak of EF-2expression levelappeared at7d. Prx gene expression in hepatopancreas was induced by1μg·L^-1of OPat1d, and it was also inducedin gills. ADRP gene expression was firstly inhibited,andthen induced in hepatopancreas. ADRPgene expression was also induced in muscleand serum. After7d recovery, some gene expressions restored.Stomach, intestines and gills of P. monodonwere obviously damagedafterlong-term exposure of OP. The epithelial tissue of inner wall necrosis instomachand intestines showed shedding, rupture and vacuoles. The cells arrangementwerescattered, and the structure of cell was not clear, with enlargement of the cell nucleus.The lesion of gill displayed gill filaments break, organization vacuolated andenlargement of the cell nucleus.SOD activity in visceral mass ofGafrarium tumidum was induced by OP,whilesignificantly inhibited in mantle. GST activity were also induced andinhibited in visceral mass and mantle, respectively. GSH content in visceral massdecreased significantly at1d. In0.04and1mg·L^-1concentration groups, GSH contentof mantle were significantly reduced as well, then increased as the time progressed. In0.2mg·L^-1concentration group, the MDA content of visceral mass showed an trend ofincreased-decreased-increased. T-AOC of visceral mass and mantle were reducedsignificantly. Lower concentrations (0.04and0.2mg·L^-1) of OP can activate theinhibition of OH radical capacity in visceral mass; inhibition of OH radical capacityof mantle was always inhibited.SOD activity in visceral mass and mantle were inhibited in the early exposurestage, and then increased. Lower concentrations of OP (0.4and2mg·L^-1) could resultin the repression of GST activity in visceral mass and mantle, and then theinhancement of GST activity was observed. When the concentration increased to10mg·L^-1, GST activity was always depressed. OP can induce the production of GSH,while high concentration of OP (10mg·L^-1) inhibited the yield of GSH. After exposedby OP, MDA levelsin visceral mass and mantle significantly increased. In addition,T-AOC of visceral mass was significantly reduced, while T-AOC was induced inmantle. OP can induce the inhibition of OH radical capacityin visceral mass andmantle. After transferred to clean seawater for72h, only MDA content in mantlerestored.