Characterisation of Lactobacillus fermentum SM-7 isolated from koumiss, a potential probiotic bacterium with cholesterol-lowering effects.

BACKGROUND: Lactic acid bacteria (LAB) have been demonstrated to have cholesterol-reducing effects in many studies. RESULTS: Lactobacillus fermentum SM-7 screened from ten LAB strains isolated from koumiss, a fermented milk drink, reduced cholesterol by 66.8%. It also showed acid and bile tolerance as well as antimicrobial activity against pathogenic Escherchia coli and Staphylococcus aureus. Lactobacillus fermentum SM-7 cells assimilated 61.5% and co-precipitated and absorbed 38.5% of the cholesterol in the media. Co-precipitation of cholesterol with cholic acid increased rapidly at pH levels below 6. In vivo experiments using L. fermentum SM-7 on artificially induced hyperlipidaemial ICR mice significantly decreased serum total cholesterol and total triglyceride levels, low-density lipoprotein cholesterol concentrations and atherogenic index (P < 0.01), while serum high-density lipoprotein cholesterol concentrations did not increase significantly (P > 0.05). The body weight and liver weight/body weight ratio of SM-7 groups were lower than those of mice on a high-cholesterol diet that were not given lactobacilli. There was no bacterial translocation in the liver, spleen or kidney of experimental mice. CONCLUSION: The results suggested that L. fermentum SM-7 is a potential probiotic bacterium with cholesterol-lowering effects.

Functional characteristics of Lactobacillus fermentum F1.

In this study, Lactobacillus fermentum (L. fermentum) F1 reduced cholesterol 48.87%. The strain was screened from cattle feces using an API 50 CHL system and the 16S rRNA sequence contrasting method. L. fermentum F1 showed acid and bile tolerance, and antimicrobial activity against pathogenic Escherichia coli and Staphylococcus aureus. L. fermentum F1 deconjugated 0.186 mM of free cholalic acid after it was incubated at 37°C in 0.20% sodium taurocholate (TCA) broth for 24 h. Heat-killed and resting cells of L. fermentum F1 showed small amounts of cholesterol removal (6.85 and 25.19 mg/g, respectively, of dry weight) compared with growing cells (33.21 mg/g of dry weight). The supernatant fluid of the broth contained 50.85% of the total cholesterol, while the washing buffer and cell extracts had 13.53 and 35.39%, respectively. These findings suggest that L. fermentum F1 may remove cholesterol by co-precipitating with deconjugated bile salt, assimilating with cells and by incorporation into cellular membranes. Cholesterol assimilated by cells held 72.0% of the reduced cholesterol, while 21.65% of the reduced cholesterol was coprecipitated with deconjugated bile salt and 5.89% was adsorbed into the surface of the cells.

[Growth and propagation of wild Pinellia ternata in cultivation].

OBJECTIVE: To study the growth and propagation of Pinella ternata in cultivation. METHOD: Forty six populations of P. ternata originated from Sichuan, Shanxi province and chongqing city were collected and cultivated in experimental field under the same cultivation condition. RESULT AND CONCLUSION: Reproduction tubers at the weight of 0.51-2.00 g (diameter 0.9 - 1.5 cm) had higher increments of tubers and general weight. The P. ternata populations originated from Peng-an county, Shehong county, Zhongjiang county, Lezhi county, Lu county grew faster, on the other hand, the populations originated from Lezhi county, Guangyuan county, Peng-an county, Jianyang county had stronger ability of propagation. The sprouting rate of above 0.30 g (diameter 0.7 cm) tubers was about 90%. There was no significant difference in the growth between tubers and bulbils that have the same weight. The two factors that affected the yield increment were weight range and population, and the former was the main one. Significantly positive correlations were found between weight of reproduction tuber and weight of harvested tubers, number of bulbils. However, significantly negative correlations were found between weight of reproduction tuber and weight increments of tubers, increments proportion of tubers and general weight, and a negative correlations was found between weight of reproduction tuber and general weight increments. Curve-estimated models were conjectured about the weight of reproduction tuber and growth or propagation parameters such as the diameter, the sprouting rate, increments of tubers and general weight, increments proportion of tubers and general weight and the number of bulbils. Some proposals to improve the cultivation of P. ternate were suggested.