• Journal of Microbiology and Biotechnology
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• v.33 no.5
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• pp.621-633
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• 2023

We investigated the probiotic characteristics and anti-obesity effect of Lactiplantibacillus plantarum MGEL20154, a strain that possesses excellent intestinal adhesion and viability. The in vitro properties, e.g., gastrointestinal (GI) resistance, adhesion, and enzyme activity, demonstrated that MGEL20154 is a potential probiotic candidate. Oral administration of MGEL20154 to diet-induced obese C57BL/6J mice for 8 weeks resulted in a feed efficacy decrease by 44.7% compared to that of the high-fat diet (HFD) group. The reduction rate of weight gain was about 48.5% in the HFD+MGEL20154 group compared to that of the HFD group after 8 weeks, and the epididymal fat pad was also reduced in size by 25.2%. In addition, the upregulation of the zo-1, pparα, and erk2, and downregulation of the nf-κb and glut2 genes in Caco-2 cells by MGEL20154 were observed. Therefore, we propose that the anti-obesity effect of the strain is exerted by inhibiting carbohydrate absorption and regulating gene expression in the intestine.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.414-419
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• 2018

Escherichia coli O157:H7 is one of the most common foodborne pathogens responsible for outbreaks of hemorrhagic colitis, which can lead to the life-threatening hemolytic-uremic syndrome. In this study, we identified phytochemicals that specifically inhibit the expression of LEE operon in E. coli O157:H7. Among phytochemicals, diosmin decreased the adherence of E. coli O157:H7 towards Caco-2 cells in vitro (p<0.01) and its biofilm formation activity (p<0.05). Quantitative RT-PCR analysis revealed that the transcripts of Ler-regulated genes and genes related to curli production were significantly reduced in the presence of diosmin. However, diosmin does not affect bacterial viability, indicating that the resistance rate to diosmin was remarkably low. Overall, these results provide significant insights into the development of a novel anti-infective agent that is different from conventional antibiotics.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1747-1754
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• 2018

The objective of this study was to evaluate probiotic effects of two Lactobacillus plantarum strains (GBL16 and 17) isolated from black raspberry. Results revealed that the number of GBL16 was gradually decreased as bile salt concentration was increased from 0.3 to 1%. However, GBL17 did not show any difference when GBL17 was applied to 1% bile salt, and it indicates that GBL17 is more tolerant to bile salt than GBL16. GBL17 exhibited higher heat resistance and adhesion ability to Caco-2 cells than GBL16. Regarding gut microbiome, no significant change in the number of total bacteria in intestines of mice after treatment with GBLs was determined. However, the combination of GBL16 and GBL17 significantly increased the number of total bacteria in intestines of mice after they were orally administered. Therefore, the results suggest that both GBL16 and 17 strains could be one of major probiotics that can improve human gut health.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.127-127
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• 2018

Probiotics are microorganisms that have beneficial effects on the health of the host. The health promoting effect by probiotics influences suppressing harmful bacteria, prevention of constipation, blood cholesterol reduction and regulation of blood pressure. Prebiotics are used to promote the growth or activity of microorganisms. Synbiotics, which are a mixture of probiotics and prebiotics, synergize in the intestines by complementing each other. Synbiotics not only improves the viability of the probiotics while passing through the gastrointestinal tract, maintain intestinal homeostasis, but also regulate balance of harmful and useful bacterial growth. Glycine max Merr (GMM) has been widely used in Asian countries to treat cancer, obesity, oxidative stress and imbalanced immune diseases. In addition, it has been reported that dietary fiber-rich grains promote bowel movements and prevent constipation. In this study, we investigated the viability of LactobacillIus buchneri (L.buchneri) strains, known as lactic acid bacteria under conditions of gastric fluid and intestinal fluid to determine the suitability of L.buchneri as probiotics. The adhesion ability of L.buchneri to caco-2 cells was also confirmed. The present studies showed that GMM extract promoted the growth and activity of L.buchneri strains as prebiotics. Also, this results suggested that the mixture of L.buchneri and GMM extract can helps maintain intestinal health and healthy body as synbiotics and health functional food material.

• Journal of Life Science
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• v.24 no.11
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• pp.1231-1237
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• 2014

The objective of this study was to evaluate the safety and functional properties of four potential probiotic strains isolated from Kimchi, traditional Korean fermented vegetables. Based on being higher tolerance to bile salts and showing higher acid resistance or hydrophobic properties, one Lactobacillus arizonensis strain (BCNU 9032) and three L. brevis strains (BCNU 9037, BCNU 9098 and BCNU 9101) were selected in the screening experiment. All strains can survived up to 99% after 3h culture in pH 2.5 and resistant to 1% bile salts. These strains also showed good antimicrobial activities against a number of food borne pathogens, especially against Escherichia coli and Shigella sonnei. The ability to lower cholesterol levels of L. arizonensis BCNU 9032 and L. brevis 9037 were demonstrated by bile salt hydrolytic activity and cholesterol assimilation tests. Moreover, L. brevis BCNU 9098 and BCNU 9101 showed higher adherence to Caco-2 cells (12.76 and 11.86%, respectively) than Lactobacillus rhamnosus GG, a commercial probiotic strain used worldwide. The results suggest that these strains could be used as probiotics.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1510-1517
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• 2012

To evaluate the probiotic potential of Bacillus polyfermenticus CJ6 isolated from meju, a Korean traditional soybean fermentation starter, its functionality and safety were investigated. B. polyfermenticus CJ6 was sensitive to all antibiotics listed by the European Food Safety Authority. The strain was also non-hemolytic, carried no emetic toxin or enterotoxin genes, and produced no enterotoxins. The resistance of B. polyfermenticus CJ6 vegetative cells and spores to simulated gastrointestinal conditions was high (60-100% survival rate). B. polyfermenticus CJ6 produced high amounts (0.36 g as a purified lyophilized form) of ${\gamma}$-polyglutamic acid (PGA). We speculate that the improved cell viability and the production of ${\gamma}$-PGA have a significant correlation. Adhesion of the strain to Caco-2 and HT-29 cells was weaker than that of the reference strain (Lb. rhamnosus GG), but it was comparable to or stronger than those of reported Bacillus spp. When B. polyfermenticus CJ6 spores were given orally to mice, the number of cells excreted in the feces was 4-fold higher than the original inocula. This suggests the inoculated spores propagated within the intestinal tract of the mice. This idea was confirmed by field emission scanning electron microscopy, which revealed directly that B. polyfermenticus CJ6 cells germinated and adhered within the gastrointestinal tract of mice. Taken together, these findings suggest that B. polyfermenticus CJ6 has probiotic potential for both human consumption and use in animal feeds.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1971-1982
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• 2017

Piliated Lactobacillus rhamnosus (pLR) strains possess higher adherent capacity than non-piliated strains. The objective of this study was to isolate and characterize probiotic pLR strains in human fecal samples. To this end, mouse polyclonal antiserum (anti-SpaA) against the recombinant pilus protein (SpaA) of L. rhamnosus strain GG (LGG) was prepared and tested for its reactivity and specificity. With the anti-SpaA, a method combining the de Man, Rogosa, and Sharpe (MRS) agar plating separation and colony immunoblotting (CIB) was developed to isolate pLR from 124 human fecal samples. The genetic and phenotypic characteristics of the resultant pLR isolates were compared by randomly amplified polymorphic DNA (RAPD) fingerprinting, and examination of adhesion to Caco-2 cells, hydrophobicity, autoaggregation, and in vitro gastrointestinal tolerance. Anti-SpaA specifically reacted with three pLR strains of 25 test strains, as assessed by western blotting, immunofluorescence flow cytometry, and immunoelectron microscopy (IEM) assays. The optimized MRS agar separation plus anti-SpaA-based CIB procedure could quantitatively detect $2.5{\times}10^3CFU/ml$ of pLR colonies spiked in $10^6CFU/ml$ of background bacteria. Eight pLR strains were identified in 124 human fecal samples, and were confirmed by 16S RNA gene sequencing and IEM identification. RAPD fingerprinting of the pLR strains revealed seven different patterns, of which only two isolates from infants showed the same RAPD profiles with LGG. Strain PLR06 was obtained with high adhesion and autoaggregation activities, hydrophobicity, and gastrointestinal tolerance. Anti-SpaA-based CIB is a rapid and inexpensive method for the preliminary screening of novel adherent L. rhamnosus strains for commercial purposes.