Cricket Neuropeptide Gene Grb-of Ast <sub> 6 </ Sub> Series The Expression Of The Body And Insects Efficiency Study

Allatostatin (Ast) is a kind of hormone secreted from Gryllusbimaculatus brain.Studies show it inhibit the biosynthesis of the Juvenile Hormone(JH) of insects by corpora allata(CA) In vitro.The gene of AST encode 15 polypeptides .The capacity of inhiobit the Jh is not the same. Study of molecular biology shows that they shares the same N-end sequence:Y/FXFGL/I/V.The amino acid sequence of Grb-AST76is N-SRPFGFGL, totally eight residues Grb-AST6 is the sixth polypeptide of the 15 polypeptides of AST. Improved"self template-primer" PCRmethod was used to construct Grb-AST6.concatemer.Firstly,a pair of primers was designed and the single Grb-ast6 was linked by T4 DNA Polymerase secondly, PCR was used to colne the intented gene.As a result, a 16 copies Grb-ast was acquired.The Grb-ASTe concatemer was expressed in pET21, pET22, pET30 and pQE30 in E.coli.The effect shows when the gene of Grb-AST6 was expressed in pQE30/ SG13009[pREP4],the value of express was highest in the condition the concetration(OD600)is 0.8 and IPTG is 1.0mM. The value of express is approximately 25%.The protein of Grb-ast6 is supplied to raise the Prodenia lituraand the effect of anti-insect has been studied.The results of the study shows that the protein of Grb-ast6 has a satisfied anti-insect to Prodenia lituraand.After the Prodenia Jituraand was raised by the protein of Grb-ast6 for 6 days, dead rate of treatment was higher than control.Protein of Grb-ast6 has the highest mortality against P.litura and raised for 8 days.