earticle

영어

E. tarda ghost vaccines may provide immune efficacy against edwardsiellosis in farmed fish. However, the leakage of antibioticresistance gene from cloned cells leads to occurrence of antibiotic resistant bacteria and negative effect on environment. Thus, plasmid based on an aspartate-semialdehyde-dehydrogenase (asd) gene was constructed for the E. tarda ghost vaccine to prevent the spread of the antibiotic resistance gene in environment. Target gene for the
construction of auxotrophic E. tarda was asd gene, which is an essential gene for the construction of cell wall. The auxotrophic strain was generated by allelic exchange using a suicidal vector harboring DNA segments for asd gene deletion. A pBR origin, asd gene from
pYA3342 and E lysis gene controlled by lambda PR/cI regulatory system from pGhost were transfered into the recombinant plasmid. Efficient promoter and signal peptide systems on the vector will be studied for better antigen expression and delivery of the antigen to outer membrane. The auxotrophic E.tarda ghost vaccine with antigen delivery system can lead to safe environment with as antibiotic-free system and increase the protection efficacy against dwardsiellosis.