Abstract

The minC gene of Lactobacillus acidophilus VTCC-B-871 was identified based on the genome data of L. rhamnous strains in genebank, and antimicrobial activities other than cell division inhibitor was detected. After cloning and sequencing, there was 99.1% homology betweenminC gene of L. acidophilus VTCC-B-871 and L. rhamnous GG using Blast search. By analysis, the result also showed the close relation between these strains that was necessary in the identification of these probiotics. Besides, using pET21a(+) vector for the over-expression of minC protein in Escherichia coli BL21(DE3)plysS under 2 mM Isopropyl β-D-1-thiogalactopyranoside within 5 h, the filamentation occurred and showed that minC was functional across species. Especially, the study detected successfully, the antimcrobial activities on Pseudomonas aeruginosa ATCC 27853 in the cultures containing glucose, saccharose and manitol. The antimicrobial agent still showed the activities after treated with temperature at 100, 90, 80, 70, and 60°C in 15 min, but loss activity after protease K treatment at 10 mg/ml for 30 min. The characterization pointed the antimicrobial agent seemed as colicin in E. coli. The present work was the first reported in characterizing theLactobacillus minC homolog that might be useful in probiotic classification and antibioticproduction.

Key words: Antimicrobial activities, cell division inhibitor minC, comparative analyses,Lactobacillus acidophilus VTCC-B-871, morphology changes.