Total RNA was separated from the abdomen of house fly,after which had been challenged for 24 hours with E. coli and Staphylococcus aureus . Then,the mRNA was purified from it. After that,ds cDNA was synthesized by reverse transcriptase from mRNA,and small cDNA which was lower than 400?bp was removed by Sepharose CL 4B spun column. After Eoc RⅠ/ Not Ⅰ Adaptors were added to cDNA,those that weren’t ligated to cDNA were removed by another Sepharose CL 4B spun column. The cDNA was inserted into λgtll,the recombined vector packaged in vitro ,infected a host strain Y1090. Thus,the cDNA library was constructed. The titer of the newly constructed cDNA library was 3 46×10 5 pfu/mL,and its recombination rate was 99 6%. The library would provide basis for the cloning of the antimicrobial peptide genes of house fly.
