• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1201-1209
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• 2006

The purpose of this study was to isolate probiotic lactic acid bacteria (LAB) that produce bile salt hydrolase (BSH), and to evaluate its effects on serum cholesterol level. One-hundred-twenty bacterial colonies were initially isolated from human feces, and five strains were selected after screening based on their resistance to acids, tolerance against bile salts, and inhibitory activity on Escherichia coli. The Lactobacillus plantarum strain with the highest level of BSH activity was identified using 16S rRNA sequences, and was named L. plantarum CK 102. L. plantarum CK 102 at a level of 1.36$\times$10$^8$cfu/ml survived in pH 2 buffer for 6 h and exhibited excellent tolerance for bile salt. Coculturing the strain with E. coli in MRS broth resulted in strong inhibition against growth of E. coli at 18 h. Furthermore, the potential effect of CK 102 on serum cholesterol level was evaluated in rats. Thirty-two rats [Sprague-Dawley (SD) male, 129$\pm$l g, 5 weeks old] were divided into four groups of eight each. For six weeks, Group 1 was fed a normal diet (negative control); Group 2 was fed a cholesterol-enriched diet (positive control); Group 3 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 1.0$\times$10$^7$cfu/ml; and Group 4 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 5.0$\times$10$^7$cfu/ml. Blood samples were collected, serum lipids were analyzed, and weights of the organs were measured. Total blood cholesterol level, triglyceride, LDL-cholesterol, and free-cholesterol values were lower in rats that were fed 1. plantarum CK 102 than in those not fed L. plantarum CK 102. This cholesterol lowering effect implies that L. plantarum CK 102 could be utilized as an additive for health-assistance foods. In conclusion, these results suggest that the 1. plantarum CK 102 isolated could be used commercially as a probiotic.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.568-577
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• 2015

To protect skin problems, new natural material alternative to synthetic antioxidants has been extensively selected from natural sources such as plants, animals, and microorganisms. Poncirus trifoliata of those has been widely used as treatment of allergy, chronic inflammatory diseases, and natural antioxidant. In recent days, microbial fermentation to natural products has been reported to increase feasibly their bioavailability. Accordingly, we performed the fermentation using hot water extract of Poncirus trifoliata by isolated Leuconostocs sp. strain JYK and investigated the change of antioxidative activity. Antioxidative material such as hesperidine naringine, imperatorin, and luteolin was found in hot water extract of Poncirus trifoliata. Total phenolics compounds and flavoniods in hot water extract were $71.2{\pm}4.58GAE(mg/g)$ and $25.1{\pm}4.12$ hesperidine(mg/g), respectively. After fermentation, their values were $89.2{\pm}13.47GAE(mg/g)$ and $31.0{\pm}4.06$ hesperidine(mg/g), respectively. After fermentation, ABTS[2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)] and DPPH(1,1-diphenyl-2-picrylhydrazyl) radical were highly enhanced from $70.2{\pm}9.01$ to $86.2{\pm}3.72$ and $18.7{\pm}1.81$ to $26.6{\pm}4.06$, respectively. Thus microbial fermentation offers a tool to further increase the bioactive potential of Poncirus trifoliata.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.363-370
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• 2007

In order to identify probiotic microorganisms, 25 isolates of Lactobacillus sp. were selected from kimchi based on their growth rates, lactic acid production and salt tolerance. The isolate JK-01 was identified as Lactobacillus plantarum by the API kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum JK-01. The maximum number of L. plantarum JK-01 was reached at 18 hr fermentation in MRS broth and the pH gradually decreased to 4.5. L. plantarum JK-01 showed high enzyme activities for xylanase, amylase, protease, and phytase on MRS agar plates containing each substrate. L. plantarum JK-01 showed high resistance to acidic pH and bile salts, and grew well even at pH 2.0 and 1.0% bile salt. In particular, L. plantarum JK-01 showed high heat stability as shown by $3.3{\times}10^3$ CFU/mL at $60^{\circ}C$. The isolate showed remarkable antimicrobial activity against E. coli in MRS broth based on its disappearance after 18 hr and clear zone formation using a paper disk assay. These results suggest that L. plantarum JK-01 may be probiotic in nature.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.959-967
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• 2004

To screen probiotic lactic acid bacteria with potent adhesive property on human colonic mucosa, colonic mucin-binding assay was introduced. This colonic mucin-binding assay actually measures the binding activity of surface lectin-like protein (SLP) on colonic mucin, and the optimal conditions were examined. The optimal pH for colonic mucin coating on plate wells was 4.8, and ${\times}24,000$ diluted solution of commercially available horseradish peroxidase (HRP) conjugated streptoavidin yielded good results, for rapid screening, $5.0\;{\mu}g/mL$ of biotinylated SLP from lactic acid bacteria was optimal, and optimal scintillation time of 3,3',5,5'-tetramethyl benzidine (TMB) was 10 min. These conditions were useful for both rapid selection and quantitative analysis of lactic acid bacteria that have high adhesion property to human intestinal tract. Among 50 strains of lactic acid bacteria, including 32 type culture strains and 18 isolated strains from infant feces, Lactobacillus species FSB-1 isolated from kimchi showed the highest binding activity to colonic mucin. From taxonomical viewpoints based on morphological study, physico-biochemical study, partial 16S rDNA seguencing, and phylogenetic analysis, L. species FSB-1 was identified as Lactobacillus brevis.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.225-236
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• 2013

Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at $30^{\circ}C$. Interestingly, antibacterial activity remained unchanged after heating at $121^{\circ}C$ for 45 min, 24 h storage in temperature range of $70^{\circ}C$ to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.

• Journal of fish pathology
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• v.33 no.2
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• pp.145-151
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• 2020

The whiteleg shrimp Litopenaeus vannamei can survive in a wide range of salinity (1-40 psu). However, such variation, particularly at low salinity (1-5 psu), can affect various physiological changes such as survival rates, non-specific immunity and disease resistance. In this study, growth, non-specific immunity and disease resistance were measured following simultaneous oral feeding and addition of probiotic microbes into culture water for 73 day period. The salinity of the culture water was maintained at 3 psu by periodical salt additions. The result shows that survival rate increased significantly (5.6 vs. 15.4%) after 73 day rearing. Significant increases were identified in reactive oxygen species (ROS) production and phenol oxidase (PO) activity. However, superoxide dismutase (SOD) activity was not influenced. When the shrimp was artificially challenged with Vibrio alginolyticus, slight mortality reduction was observed in the probiotics-treated group (100 vs. 79%). In conclusion, the production of cultured whiteleg shrimp at low salinity might be increased by probiotics survivable at low salinity levels.

• Journal of Dairy Science and Biotechnology
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• v.35 no.4
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• pp.221-231
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• 2017

This study aimed to investigate the physiological characteristics and anti-obesity effects of a newly isolated bacterium, Lactobacillus plantarum K6. L. plantarum K6 showed good ${\alpha}-amylase$ inhibitory activity ($96.78{\pm}3.29%$), ${\alpha}-glucosidase$ inhibitory activity ($92.55{\pm}9.62%$), and lipase inhibitory activity ($85.17{\pm}0.79%$), and the strain inhibited the adipocyte differentiation of 3T3-L1 cells ($27.4{\pm}1.4%$) when present at a concentration of $100{\mu}g/mL$. L. plantarum K6 was isolated from kimchi and its physiological characteristics were investigated. A comparison of the sensitivity of the isolate to 15 different antibiotics showed that L. plantarum K6 is highly sensitive to erythromycin and highly resistant to vancomycin, ampicillin, and polymyxin B. This strain also showed high arylamidase and ${\beta}-galactosidase$ activities. Moreover, it was relatively tolerant to bile acid and low pH, and displayed resistance to Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, with rates of 51.8%, 42.4%, 61.6%, and 54.9%, respectively. No bio genic amines were produced. L. plantarum K6 also showed high adhesion activity to HT-29 cells compared to L. rhamnosus GG. These results demonstrate that Lactobacillus plantarum K6 has potential as a probiotic with anti-obesity effects.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.647-655
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• 2014

Obesity is strongly associated with several metabolic and chronic diseases and has become a major public health problem of worldwide concern. This study aimed to investigate the physiological characteristics and anti-obesity effects of Lactobacillus plantarum Q180. Lactobacillus plantarum Q180 was isolated from the faces of healthy adults and found to have a lipase inhibitory activity of $83.61{\pm}2.32%$ and inhibited adipocyte differentiation of 3T3-L1 cells ($14.63{\pm}1.37%$) at a concentration of $100{\mu}g/mL$. The strain was investigated for its physiological characteristics. The optimum growth temperature of L. plantarum Q180 was $37^{\circ}C$. Lactobacillus plantarum Q180 showed higher sensitivity to novobiocin in a comparison of fifteen different antibiotics and showed the highest resistance to rifampicin, polymyxin B and vancomycin. The strain showed higher ${\beta}$-galactosidase and N-acetyl-${\beta}$-glucosaminidase activities. It also did not produce carcinogenic enzymes such as ${\beta}$-glucuronidase. The survival rate of L. plantarum Q180 in MRS broth containing 0.3% bile was 97.8%. Moreover, the strain showed a 97.2% survival rate after incubation for 3 h in pH 2.0. Lactobacillus plantarum Q180 was displayed resistance to Escherichia coli, Salmonella Typhimurium and Staphylococcus aureus with rates of 55.6%, 38.0% and 47.6%, respectively. These results demonstrate that L. plantarum Q180 has potential as a probiotic with anti-obesity effects.

• Journal of Dairy Science and Biotechnology
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• v.22 no.2
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• pp.91-97
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• 2004

The antioxidative ability on the basis of reduced glutathione sulphydryl(GSH) level, the inhibition activities of linoleic acid peroxidation of cell free extract of Lactobacillus spp. and Bacillus spp. have been determined; Lactobacillus casei CU4114 contained the highest level of GSH among the probiotic strains with 25.15 ${\mu}$mole/g. Significantly high level of GSH occured in the intracellular cell free extract of Lactobacillus rhamnosus CU4201, Lactobacillus plantarum CU4203. The antioxidant activity and inhibition of linoleic acid peroxidation of cell free extract of Lactobacillus spp. and Bacillus spp. by thiobarbituric acid(TBA) assay have been shown to be significantly differed depending on the strains(P>0.01). Intracellular cell free extracts of L. acidophilus CU4111, L. casei CU4114, and strains of Bacillus coacillus revealed a significantly intensive inhibitory activity in the linoleic acid peroxidation reactions. Spearmans' rank correlation between inhibitory activity on linoleic acid peroxidation and cellular GSH levels of Lactobacillus spp. was analysed and the correlation quotient was 0.65 which means a significant positive correlation.

• International Journal of Oral Biology
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• v.44 no.4
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• pp.152-159
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• 2019

The oral care probiotic strain Weissella cibaria CMU (oraCMU) inhibits volatile sulphur compounds associated with halitosis, presumably by inhibiting the growth of associated oral pathogens. In the present study, we investigated whether oraCMU inhibits the production of these compounds by suppressing the expression of mgl. This gene encodes L-methionine-α-deamino-γ-mercaptomethane-lyase (METase) and is involved in the production of methyl mercaptan (CH₃SH) by Porphyromonas gingivalis. Therefore, we specifically investigated the effects of oraCMU on the growth, CH₃SH production, METase activity, and mgl expression of P. gingivalis. The minimum inhibitory concentrations of cell-free supernatant and secreted proteins from oraCMU were 125 mg/mL and 800 ㎍/mL, respectively. At sub-minimum inhibitory concentration levels, these metabolites inhibited CH₃SH production, but they also reduced P. gingivalis viability. Only heat-killed oraCMU decreased CH₃SH production without affecting P. gingivalis viability. Heat-killed oraCMU also inhibited METase activity toward L-methionine and mgl mRNA expression (p < 0.05). In summary, we demonstrated the inhibition of volatile sulphur compounds via the antimicrobial action of oraCMU and, for the first time, the inhibition of such compounds by heat-killed oraCMU, which occurred at the molecular level.