The Mechanism Of Vitellogenin Of Aleurolyphus Ovatus(Troupeau)(Acarina:Acaridae) Responses To Lead Stress

Heavy metal pollution has become a worldwide environmental pollution problem,because it is non-degradable and can be enriched by the food chain,which has a great impact on the growth and reproduction of organisms in the ecosystem.The vitellogenin is a precursor of insect vitelline and is the key material basis of insect reproduction.Aleurolyphus ovatus?Troupeau?is a kind of storage pest that can be quickly reproduction and easily reared.The research on the factors affecting its reproduction is conducive to the theoretical basis of the prevention and control of pest mites.In this paper,A.ovatus was used as a research object to clone and analyze the sequence of vitellogenin?Vg?gene related to its reproduction.Lead was added to artificial diet,and five concentration gradients?including control?were set(0 mg?kg^-1,12.5 mg?kg^-1,25mg?kg^-1,50 mg?kg^-1,100 mg?kg^-1),the expression of vitellogenin gene after long-term lead stress at different concentrations were determined.Western Blot and ELISA kit were used to determine AOVg Protein content under different concentrations and different time stress.The main results are as follows:1.In this study,the full-length cDNA of AOVg gene was obtained.AOVg was 6270bp with the open reading frame?ORF?of 6030 bp,which encoding a total of 2009amino acid residues.The length of the 5'untranslated region?UTR?was 128 bp,3'The UTR is 112 bp in length.The Vg protein has three conserved regions of Vitellogenin-N,DUF1943 and VWD,and with a signal peptide of 19 amino acids.The GL/ICG,DGXR conserved sequence and cysteine residue?C?were found in AOVg amino acid sequence C-terminus.2.A conserved fragment of AOVg protein containing 258 amino acids was successfully expressed.The prokaryotic expression product was 49.18kDa,named pET-32a-AOVg,and the recombinant protein was secreted in the form of inclusion bodies.The AOVg polyclonal antibody,named Anti-AOVg,was successfully prepared and has a good specificity for AOVg tested by Western Blot.3.Lead stress affected the transcription and translation of Vg gene in A.ovatus.Low concentration of lead stress had little effect on AOVg and slightly promoted its expression,but high concentration of lead stress significantly promoted AOVg gene expression.On the whole,with the increase of lead stress concentration,the promotion effected of lead stress showed a trend of increasing first,then decreasing and then increasing.The results of AOVg protein content under different concentrations of lead stress showed that the AOVg protein content increased first and then decreased with the increase of lead stress concentration.But the AOVg protein content had an increasing trend at 100 mg?kg^-11 lead concentrations.