Generation of Vibrio anguillarum Ghost by Coexpression of PhiX 174 Lysis E gene and Staphylococcal Nuclease A Gene

Vibrio anguillarum ghosts (VAG) were generated, for the first time, using a conjugation vector containing a ghost bacteria inducing cassette, pRK-lambda P-R-cI-Elysis, in which the expression of PhiX174 lysis gene E was controlled by the P (R) /cI regulatory system of lambda phage. By scanning electron microscopy, holes ranging 80-200 nm in diameter were observed in the VAG. To avoid the presence of bacterial genomic DNA and an antibiotic resistance gene in the final VAG product, we constructed a new dual vector, pRK-lambda P-R-cI-E-SNA, containing the E-mediated lysis cassette and the staphylococcal nuclease A (SNA)-mediated DNA degradation cassette, and generated safety-enhanced VAG for use as a fish vaccine.