Study On The Mutation Breeding Of High Bacteriocin-producing Strain WJK84-1 And The Antimicrobial Mechanism Against

Based on the means of mutations with UV, a high bacteriocin-producing mutant WJK84-1 was successfully obtained when the original strain K84 treated by the method of competitive selection. Antimicrobial activities and the antimicrobial mechanism against crown gall disease were tested. Through the method of agar diffusion assay and culture in liquid medium, the result showed that the strain of WJK84-1 and its secondary metabolites P-2001 all had strong inhibition to the strain of C58. SDS-PAGE demonstrated that the content of total protein in C58 decreased, especially the protein of large molecule, some of them (R1,R4)even disappeared. The inhibition increased along with the increased concentration of the bacteriocin. Observation under scanning electron microscope revealed that the structure of C58 was destroyed by bacteriocin, and changed its shapes, at last, constricted into little particles and died. The result of transmission electron microscope demonstrated that the strain of C58 become highly irregular and shrank with condensed plasma, vesicle and wild periplasmic space. By the long time effected by P-2001, the structure of C58 was severely destroyed. The integration of the wall and membrane were dilapidated with cell disintegrations and plasma leakage. The experiment of antitumor in Cherry indicated that the strain of WJK84-1 and its product bacteriocin all had higher antitumor effect on the crown gall disease in Cherry, the inhibitory rate achieved about 85 percent.