Effects Of Insecticides On Some Enzymes And Protein Phosphorylation In Monochamus Alternatus Hope

Monochamns alternatus Hope (Coleoptera:Cerambycidae) is not only a serious pest to Pinus but also the main vector of pine wood nemadote Bursaphelenchus xylophilus, which causes pine wilt disease. There's many researches on this insect about its biology, ecology, and the methodology of its control. In this thesis, methamidophos, deltamethrine, and imidacloprid were chosen to be the representatives of three kinds of insecticides to test its effect on acetylcholinesterase (AChE), glutathione-s-transferase (GST), and carboxylesterases (CarE). The author studied the effect of methamidophos and deltamethrine on protein phosphorylation of this insect using radioactive isotope labeling method. In addition, we assayed activity of neurotoxic esterase (NTE) in this pest insect, and tried to do primary culture of the hemocytes and fat body cells from this insect. The details of the results are as follows:Methamidophos could inhibit not only AChE,and CarE but also GST, in vitro; the I₅₀ values of the inhibition concentrations are 8.19×10^-M, 1.95×10^-7 M, and 0.908 M for the three enzymes respectively.It is certain that there is NTE activity in Monochatnus alternatus. The activity of the head of the insect is higher than that of other parts. It has not been observed that methamidophos can inhibit NTE activity in vitro, which is quite different from the situation found in vertebrates.Methamidophos and deltamethrin have significant effect on the phosphorylation of proteins from Monochamus alternatus larva; however, the effect of the two insecticides on the protein phosphorylation of the adult is less significant than that of the larva.Deltamethrin enhance the phosphorylation of the proteins with molecular weight of 137.8 kD and 166.5 kD from fat body and head of the insect larva, respectively. It inhibits the phosphorylation of proteinsof 111.4kD, 95.3kD and 43.8kD from larva fat body, 113.2kD, 97.5kD, 50.6kD from larva head, 51.8kD, 44.3kD from adult fat body and 43.3kD from adult head.Methamidophos enhance the phosphorylation level of the proteins with molecular weight of 127.7 kD, 44.3 kD, and 238.9 kD from adult fat body but it inhibit the phosphorylation of proteins of 95.3 kD and 43.8 kD from larva fat body and 166.5kD and 124.5kD protein from larva head.We acquired many information of the protein kinase related with protein detected by autoradiography through using cAMP and calmodulin in the assay system. Because of the complicacy of the protein phosphorylation system, further research work is needed to gain more information about the protein kinase and protein phosphatase.The result of our research will be benificial to the control of Mnonchamus alternatus. The effects of methamidophos and deltamethrin on protein phosphorylation indicated that the two insecticides may have more other targets than the fatal targets which could kill insect in short time.