• Journal of Life Science
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• v.25 no.2
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• pp.180-188
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• 2015

The bacterial strain isolated from Kimchi showed antibacterial activity against Micrococcus luteus IAM 1056. The selected strain was identified as Lactococcus lactis by 16S rRNA nucleotide sequence analysis and named as Lactococcus sp. KD 28. The treatment of culture supernatant with proteinase K removed antibacterial activity, indicating its proteinaceous nature, a bacteriocin. This bacteriocin was sensitive to hydrolytic enzymes such as ${\alpha}$-chymotrypsion, trypsin, proteinase K, lipase, ${\alpha}$-amylase and subtilisin A. The bacteriocin was highly thermostable and resistant to heating at $80^{\circ}C$ for up to an hour but 50 % of the total activity was remained at $100^{\circ}C$ for 30 min. The pH range from 2.0 to 8.0 had no effect on bacteriocin activity and it was not affected by solvents such as acetonitrile, isopropanol, methanol, chloroform and acetone up to 50% concentration. The bacteriocin showed antibacterial activity against M. luteus IAM 1056, Lactobacillus delbrueckii subsp. lactis KCTC 1058, Enterococcus faecium KCTC 3095, Bacillus cereus KCTC 1013, B. subtilis KCTC 1023, Listeria ivanovii subsp. ivanovii KCTC 3444, Staphylococcus aureus subsp. aureus KCTC 1916, B. megaterium KCTC 1098 and B. sphaericus KCTC 1184. The bacteriocin was purified through ammonium sulfate concentration, SP-Sepharose chromatography and RP-HPLC. The molecular weight was estimated to be about 3.4 kDa by tricine-SDS-PAGE analysis.

• Microbiology and Biotechnology Letters
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• v.3 no.2
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• pp.63-68
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• 1975

A biological active substance was isolated from the cultured medium of Streptomyces sp. and its biochemical characteristics were investigated. Isolation process of the substance was as follows; the pH of filterate of the cultured medium was adjusted to 3.0 with N-hydrochloric acid and saturated with sodium chloride, then chloroform was added to this filterate in one fifth portions and stirred vigorously. After extracting the active substance with chloroform in 3 stages, the chloroform layer combined and evaporatea after dehydrating with sodium sulfate. The substance was found to be to be toxic to various fresh water fishes; the lethal dose for an average size Pseudorasbora parva T. et. S. was 50ug per ml. In the acidic condition, the toxicity of the substance remained fora long time, while in the alkaline state, the toxicity was decreased very fast. This substance was found to be stable to organic solvents, but labile to heat treatment. The maximal revival time of Pseudorasbora parva T. et. S. was about 20 minutes in 25 ug/ml of the substance solution.

• Journal of Ginseng Research
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• v.35 no.2
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• pp.209-218
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• 2011

Ginseng has been used as a general tonic agent to invigorate the human body as an adaptogenic agent. In a previous report, we have shown that ginseng contains a novel glycolipoprotein called gintonin. The main function of gintonin is to transiently enhance intracellular free $Ca^{2+}$ $[Ca^{2+}]_i$ levels in animal cells. The previous method for gintonin isolation included multiple steps using organic solvents. In the present report, we developed a simple method for the preparation of crude gintonin from ginseng root as well as stem and leaf, which produced a higher yield of gintonin than the previous one. The yield of gintonin was 0.20%, 0.29%, and 0.81% from ginseng root, stem, and leaf, respectively. The apparent molecular weight of gintonin isolated from stem and leaf through sodium dodecyl sulfate polyacrylamide gel electrophoresis was almost same as that from root but the compositions of amino acids, carbohydrates or lipids differed slightly between them. We also examined the effects of crude gintonin from ginseng root, stem, and leaf on endogenous $Ca^{2+}$-activated $Cl^-$ channel (CaCC) activity of Xenopus oocytes through mobilization of $[Ca^{2+}]_i$. We found that the order of potency for the activation of CaCC was ginseng root > stem > leaf. The $ED_{50}$ was $1.4{\pm}1.4$, $4.5{\pm}5.9$, and $3.9{\pm}1.1$ mg/mL for root, stem and leaf, respectively. In the present study, we demonstrated for the first time that in addition to ginseng root, ginseng stem and leaf also contain gintonin. Gintonin can be prepared from a simple method with higher yield of gintonin from ginseng root, stem, and leaf. Finally, these results demonstrate the possibility that ginseng stem and leaf could also be utilized for ginstonin preparation after a simple procedure, rather than being discarded.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.549-556
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• 2009

In situ chemical oxidations (ISCO) are technologies for destruction of many contaminants in soil and groundwater, and persulfate has been recently studied as an alternative ISCO oxidant. Trichloroethylene (TCE) and tetrachloroethylene (PCE) were chosen for target organic compounds. The objective of this study is to demonstrate the influence of initial pH (3, 6, 9, 12), oxidant concentrations (0.01, 0.05, 0.1, 0.3, 0.5 M), and contaminants concentrations (10, 30, 50, 70, 100 mg/L) on TCE/PCE degradation by persulfate oxidation. The maximum TCE/PCE degradation occurred at pH 3, and the removal efficiencies with this pH condition were 93.2 and 89.3%, respectively. The minimum TCE/PCE degradation occurred at pH 12, and the removal efficiencies were 55.0 and 31.2%, respectively. This indicated that degradation of TCE/PCE decreased with increasing the initial pH of solution. Degradation of TCE/PCE increased with increasing the concentration of persulfate and with decreasing the concentration of contaminants (TCE/PCE). The optimum conditions for TCE/PCE degradation were pH 3, 0.5 M of persulfate solution, and 10 mg/L of contaminant concentration. At these conditions, the first-order rate constants ($k_{obs}$) for TCE and PCE were 1.04 and 1.31 $h^{-1}$, respectively.

• Journal of Life Science
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• v.19 no.7
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• pp.994-1002
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• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.