The recombinant shuttle vector pBacPAK-CTB and pBacPAK-4aa-CTB was co-infected with Bm-BacPAK6 DNA into BmN cells. The recombinant virus was screened, plaque-purified and identified by PCR and Southern hybridization.

• 重组转移载体DNA与经Bsu36I酶切线性化的修饰型病毒Bm-BacPAK6 DNA共转染家蚕BmN细胞，然后经空斑纯化、PCR扩增、Southern杂交等方法鉴定出含CTB基因的重组病毒rBm-BacCTB和rBm-Bac4aa-CTB。