Effects Of Ethacrynic Acid On Ecological Fitness And Toxicological Characterization Of GSTs From Psocids

The Liposcelis Bostrychophila and L. Entomophila Belonging to Liposcelididae, Psocoptera, Two Sub-group of Pest Insects, Are Important Causative Agents of Economic Damage to Stored Food Products. Glutathione S-transferase (Gsts, Ec 2.5.1.18) Have Been Implied in A Variety of Functions in Eukaryotic Organisms, Including Cellular Detoxification and Homeostasis. and the Gsts Activity Can Be Induced by Chemicals, Insecticides, Secondary Metabolisms of Plant, and So on. Here in This Report, We Through Studied on Ethacrynic Acid (Ea) Continuously Stimulate to L. Bostrychophila Get the Main Parameters of Life Table, in Parallel, Investigate the Influence to Gsts Activity. and the Activity of Gsts from L. Bostrychophila and L. Entamophila After Dietary on 0.5% and 3%Ea for 30 Days Were Also Investigated. the Project Was Lasted for 2 Years, and the Main Results Are As Follows:1 Influence of Ea on Ecological Fitness of L. BostrychophilaDifferent Life Table Parameters, Including Survival Rate, Development Rate, Intrinsic Rate of Increase and Developmental Time of Three Generations of L. Bostrychophila Under the Impact of Continuous Ea Treatment Were Compared Through Constructing the Life Table, to Clarify the Influence of Continuous Ea Treatment on the Ecological Fitness of L. Bostrychophila. the Results Showed That the Mean Survival Rates of Eggs Were Increased Significantly, But the Survival of the First Stadiuman Were Decreased After Dietary on Ea for Three Generations. However on Significant Difference Were Observed for Other Stage. the Adult Longevities of Two Populations After Feed on Ea for Three Generations Were All Longer Than Control, and Fi Showed the Longest Adult Period. Adult Longevity, Oviposition Period and Mean Number of Eggs in Each Generation Were Affected by the Continous Ea Treatment. the Mean Number of Eggs Laid by Per Female Was Lowest in Fi of Huaibei Populations (3%Ea) and the Control of Beibei Population,13.21 and 40.87, Respectively. According to the Life Tables, the Life Table Parameters in Each Generation After Dietary on Ea Were Calculated, Respectively. the Values of Rm Were All Decreased for Two Populations (3%Ea) and Lowest in F2, But Increased for Beibei Populations (0.5%Ea). Using Rvalues, the Fitness for F2 of Huaibei Populations (0.5%Ea and 3%Ea) and F] and F2 of Beibei Populations (3%Ea) Relative to Control Were Calculated As 0.72,0.313, 0.84 and 0.54, Respectively.2 Influence of Continous Ea Impact on Gsts of L. Bostiychophila The susceptibility of deltamethrin against L. bostrychophila after dietary on 0.5% and 3%EA for three generations were assayed by using the pesticide-membrane method. The results indicated that all generations of Huaibei populations were less susceptible to ediethyl maleate. But for Beibei populations, the psocids were more susceptible to it after feed on EA for three generations. Compared to the control, Huaibei population possessed higher specific activity of GSTs, but the F2 (0.5%EA) and F1 (3%EA) shared the lowest GSTs specific activity. GSTs in F1 of Huaibei population possessed a significantly lower affinity to the substrate GSH, but all generations of Beibei populations exhibited higher affinity to it. Meanwhile, GSTs of Beibei populations had higher catalytic activities for GSH, but no difference of catalytic activities for GSH were observed in Huaibei populations (0.5%EA) comparing with the control. The optimal pH of GSTs activity assay for each generation of two psocids was pH 7.5-8 and 37℃was considered to be optimal for the assay. The in vitro inhibition studies showed GSTs of two psocids after dietary 0.5%and 3%EA for three generations were less susceptible to ethacrynic acid, disulfiram and ediethyl maleate, and 15 mM eltamethrin exhibited poor inhibitory effects on GSTs of L. bostrychophila after dietary on 3%EA.3 Influence of EA on purified GSTs of L. bostrychophila and L. entamophilaIn order to definite the influence of ethacrynic acid on purified glutathione S-transferase from booklice. The activities of GSTs from L. bostrychophila and L. entamophila after dietary on 0.5%and 3%EA for 30 days and without EA were investigated. The results showed that the influence of EA on glutathione S-transferases from booklice exsert dose-and populations-dependent manners. After dietary of on 0.5%and 3%EA for 30 days, the LC50 values of deltamethrin form L. bostrychophila were all decreased, while for L. entamophila, the LC50 values were increased. The GSTs specific activities were decreased 1.87-and 10.00-fold (L. bostrychophila), and the GSTs specific activities of L. entamophila were also decreased after reared on the food contain 0.5%and 3%EA, respectively. GSTs of L. bostrychophila exhibited lower Km values (CDNB) and Vmax values (GSH and CDNB), but higher Km values (GSH) in comparing with control. The Km values of GSH and CDNB in L. entamophila after dietary on 0.5%and 3%EA were all deceaed respectively. The GSTs activities of L. bostrychophila and L. entamophila showed same temperature (37℃), and same pH stabilities (pH 7.0-8.0), excepting the psocids of L. entamophila (0.5%EA), who reached its activity peak at pH 6.5-7.5. The in vitro inhibition studies of GSTs indicated That the Populations of L. Bostrychophila and L. Entamophila After Dietary Ea for 30 Days Were Less Susceptible to Ediethyl Maleate and Deltamethrin Compared with Control Groups. Furthermore, As to Ethacrynic Acid, L. Bostrychophila Were Less Susceptible to Ethacrynic Acid, But L. Entamophila Were More Susceptible to It in Comparing with Control. Sds-page Revealed One Band at 23 Kda for the Psocids After Dietary on Ea.