Lactobacillus was selected as a bacterial carrier for expression of N-lobe of porcine lactoferrin(PLF N) . A pair of primers was designed with Oligo6.0 and used to amplify PLF N gene. It was in accordance with the characters of translational fusions from gene and expression vector plasmid. A 1 077 bp fragment of the gene from PLF was cloned from mammary gland tissue of the lactating sow on the third day by RT-PCR;the gene was connected with the vector plasmid pPG612.1 and transformed into the host strain JM109. The recombinant expression vector plasmid pPG612-PLF N was created and identified by using plasmid extraction,PCR,restriction enzyme digestion and sequence analysis. The recombinant plasmid was transformed into Lactobacillus casei ATCC393,Lactobacillus plantarum KLDS 1.0344,Lactobacillus paracasei KLDS 1.0652 and Lactobacillus pentosus KLDS1.0413 by electroporation,and produced the recombinant strains of pPG612-PLF N /L. casei,pPG612-PLF N /L. plantarum,pPG612-PLF N /L. paracasei and pPG612-PLF N /L. pentosus,respectively. The results indicated that PLF N gene had inserted into the expression vectors and achieved multiple Lactobacillus expression systems. It electes the base for the expression and production of recombinant porcine lactoferrin in Lactobacillus.
