Application of Recombined Plasmid pMG36e-nisI-gfp in Lactic Acid Bacteria

A constitutive expression vector for lactic acid bacteria,named pMG36e-nisI-gfp,was constructed first,using nisIas the selection marker and GFP as the reporter protein.In this work,the expression vector was electroporated into some LABs and its plasmid stability was evaluated.The results showed that the loss rate of the plasmid strains harboring pMG36enisI-gfp was still low even after 20,generations during the subculture in a liquid culture medium without antibiotics.The size and shape of the recombined strain did not change before and after subculture.The expression of GFP in the 0th,5th,10th,15th,and 20th,generations showed no significant difference.The effect of pMG36e-nisI-gfp as a reporter protein was proved in animal experiments.It was concluded that the plasmid pMG36e-nisI-gfphad good stability.