| In this study , the biological characteristic of 28 strains of Lactobacillus plantarum were analyzed, which isolated from traditional dairy products in pasture region of Inner Mongolia, such as tolerance to acid and bile salt, inhibition of their fermentation supernatant to the indicator . According to the screening experiment in vitro, L. plantarum KH13-1 was selected to a lot of studies, e.g checked the plasmid of L. plantarum KH13-1, its regulation function of immunity and intestinal flora of mice.22 strains of L. plantarum showed resistance to acid and bile salt among of tested bacteria. All of them could grow in the medium contained 0.3 % sodium taurocholate, and show tolerance to acid pH3.0 in a certain degree. 9 strains of L. plantarum could resist acid well, survival rate can even reach 150.6%. The survival rate of other strains of bacteria was different from 23.4% to 39.8%; The 9 strains of L. plantarum had a wide antimicrobial activity to pathogenic bacteria, e.g Escherichia col, Staphylococcus aureus, Shigella flexneri, Micrococcus lysodeikticus, Bacillus cereus, et al. The antimicrobial activity was weak to nonpathogenic bacteria. The antimicrobial substance was mainly organic acid and. L. plantarum KH13-1 had no plasmid.According to the screening experiment in vitro, L. plantarum KH13-1 was studied to regulation function of immunity and intestinal microflora of mice. L. plantarum KH13-1 could modulate the normal balance of intestinal microflora in mice with antibiotic-associated intestinal flora imbalance; And the results showed that the strain could enhance immune function of IDMM, but it had no effect on the specific immunity to normal mice, at the same time, its heat-killed bacteria could also induce IL-4 and IFN-γproduction by spleen cells from the mice, but live bacteria had no influence.
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