SDS-PAGE analysis of the expression of recombinant M. hyopneumoniae P36 protein in E. coli BL21(DE3) cells on LB medium. M: Protein weight marker (10-200 kDa, Bio Basic); Lane 1: Soluble P36 protein (in supernatant) of transformed E. coli BL21(DE3) cells induced with 0.8 mM IPTG when OD600 of the cultures reached 0.8 and incubated at 37oC, 150 rpm for 8 h post-induction; Lane 2: Inclusion body proteins of transformed E. coli BL21(DE3) cells in the same condition of expression; Lanes 3-4: Purified recombinant M. hyopneumoniae P36 protein.