The Specific Activities Of GSTs In Pseudorasbora Parva And Effects Of Three Insecticides On It

Effects of glutathione S-transferases by insecticides in Pseudorasbora.parva (Temminch et Schlegel)was studied in this paper.The activities of GSTs of Pseudorasbora.parva, were determined in different tissues, developmentalstages and subcellular fractions. Enzyme activities were found in liver, instestines, gill, kidney, orary,bladder, spleen, and muscle of the third age. The GSTs activities in liver were the highest in above tissues.The Km values for CDNB conjugation varied with different tissues, and the Km values of GSTs in the liverwas the lowest (2.15mmol/L). The GSTs activities toward 1-chloro-2,4-dinitrobenzene (CDNB) can bedetected in the the first age. It increased throughout the growth stages, up to the highest in the third age,and it kept on a relatively high level. It showed that GSTs activities of the first, second third and fourth agemainly distributed in the supernatant fraction of the homogenate, and the distribution in the supernatantfraction reached more than 53% of total activities in liver of the third age.The bioassay results showed that the Median lethal concentrations (LC50 (96h) ) of deltamethrin,imidaclorid, and fipronil on Pseudorasbora.parva were0.006 mg/L, and 101.80 mg/L, 0.302 mg/L,respectively, these insecticide used in water were all toxic to the fish, and the specific activities of GSTsprepared from liver, instestines, gill, kidney, ovary, bladder, spleen, and muscle of Pseudorasbora.parva weredetected. The results were analysised with the method of ANOVA to detect the differences between thetreatments and control.The optical pH of GSTs was 7.5-10.5 in livers and kidney, and 10.5 in gill; the optical temperaturewas 40℃in liver and 35℃in gill; High concentration of relative enzyme (concentration of total protein)had some inhibition on reaction rate of GSTs; and high concentration of substrates (GSH>9 mM, orCDNB>3.3mM) showed inhibiting effect on reaction rate of GSTs.The specific activities of GSTs in liver were significantly inhibited by deltamethrin at a range ofconcentration (0.005~0.009 mg/L).The rate of inhibition increased with the increasment of concentrationsof deltamethrin. When exposed to sublethal concentration of deltamethrin(0.0003mg/L)for 144 hours, thespecific activitiies of GSTs in liver were induced at 72h compared with control. When exposed toimidaclorid at lethal concentrations (40~400 mg/L), The specific activities of GSTs in liver ofPseudorasbora.parva exposed to imidaclorid, were inhibited lightly, compared with the control. It alsoshowed that different inhibition on the activities of GSTs. When exposed to sublethal concentration (10mg/L) of imidaclorid for 144 hours, the specific activities of GSTs were induced in liver at 96h, 144h inliver.As a new widely-used insecticide, fipronil was paid more and more attentions in toxicological study.The result suggested that the specific activities of GSTs were inhibited significantly by fipronil at lethalconcentrations (0.1~1.0 mg/L), and high concentrations of fipronil had more inhibiton on the specificactivity of GSTs. Sublethal concentration of fipronil (0.03mg/L) could induced specific activities of GSTsat 96h.