• Korean journal of food and cookery science
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• v.33 no.3
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• pp.256-263
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• 2017

Purpose: Essential oils are secondary metabolites of herbs and have antibacterial activities against foodborne pathogens. However, their applications for food protection are limited due to the hydrophobic and volatile natures of essential oils. Methods: In this study, essential oil nanoemulsions of rosemary and lavender were formulated with non-ionic surfactant Tween 80 and water using ultrasonic emulsification, and their antibacterial effects were determined. Results: The antibacterial activities of nanoemulsions were evaluated against 12 strains of 10 bacterial species, and significant antibacterial effects were observed against four Gram-positive and four Gram-negative bacteria but not against Streptococcus mutans and Shigella sonnei. In the disc diffusion test, the diameter of the inhibition zone proportionally increased with the concentration of nanoemulsions. Using cell turbidity measurement, minimum bactericidal concentration (MBC) of the nanoemulsions, which is the lowest concentration reducing viability of the initial bacterial inoculum by ${\geq}99.9%$, was significantly higher than the minimum inhibitory concentration (MIC) of the nanoemulsions. The largest bactericidal effects of lavender and rosemary essential oil nanoemulsions were observed against S. enterica and S. aureus, respectively. Conclusion: Nanoemulsion technique could improve antibacterial activity of essential oil nanoemulsions by increasing the solubility and stability of essential oils. Our findings shed light on the potential use of essential oil nanoemulsions as an alternative to chemical sanitizers in food protection.

• The Korean Journal of Pharmacology
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• v.16 no.1 s.26
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• pp.51-56
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• 1980

Phytolaccae Radix (PR), Brunella Herba (BH), Akebiae Lignum (AL) and Atractylis Rhizoma (AR) are some of the diuretic agents used in Chinese medicine and folk remedy. Water or methanol extracts of them (100mg/kg) were intravenously injected to rabbits in order to re-evaluate the effects on renal function. PR water extract elicited moderate diuresis while water extracts of BH, AL and methanol extract of AR had antidiuretic effects. Influence of PR on renal hemodynamics and $Na^+-K^+$-ATPase activity in rabbit kidney were observed in vivo and in vitro. The results were as follows: 1) Clearances of inulin and p-aminohippuric acid increased significantly after 15 minutes following the administration of PR water extract, but Na+ reabsorption rate was not changed. 2) The increase of $Na^+-K^+$-ATPase activity in renal cortex, outer and inner medulla was observed at 15 minutes after PR water fraction was given intravenously, and the change was most prominent in cortical area. 3) More than 50% of decrease in $Na^+-K^+$-ATPase activity in renal tissues was observed with PR water fraction $(10^{-2}g/ml)$ in vitro experiments. However, the inhibition of $Na^+-K^+$-ATPase activity was reversed with lower concentrations $(10^{-4}g/ml,\;10^{-6}g/ml)$ of PR water fraction in outer and inner medullary zone. These results suggest the diuretic effect of PR is due to improved renal hemodynamics, and contradictory reults concerning $Na^+-K^+$-ATPase activity require further investigation.

• Korean Journal of Pharmacognosy
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• v.44 no.2
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• pp.193-199
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• 2013

We investigated the antioxidative and antimicrobial activities of the methanol extracts from Korean folk plants (MKs) in Chungcheong Province. Among 30 MKs, 16 plants at $100{\mu}g/ml$ showed over 90% scavenging activity of 1,1-diphenyl-2-picrylhydrazy (DPPH) and 30 plants exerted the hydroxyl radical scavenging effect over 55%. Fourteen plants at the concentration $50{\mu}g/30{\mu}l$ showed strong microbial inhibition activity against Escherichia coli and Staphylococcus aureus, with clear zone greater than 11 mm in disc assays. Furthermore, the protective effect against anti-inflammatory system using RAW 264.7 macrophage cell was also studied. The treatment of LPS & INF-${\gamma}$ to RAW 264.7 cell induced nitric oxide (NO), however inhibit the formation of NO less than 50% of 5 plants. The present result indicates that the 30 species of MKs exerts protective effect of oxidative stress, antimicrobial activities and anti-inflammatory. In particular, Rhus javanica and Cornus controversa showed stronger effect on not only radical scavenging activity and inhibits growth of S. aureus but also highest protective effects from inflammation.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.619-623
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• 1991

To investigate nisin production and resistance of Lactococcus lactis ssp. tactis ML (L. lactis $ML_8$, effects of medium, pH of culture broth, and cell growth on the nisin activity, and effect of nisin with or without $Ca^[2+}$ ion on the growth of L. lactzs were analyzed. In the bio-assay of nisin by the agar diffusion method, inhibition-zone diameter of Micrococcus Javus was propotional to the logarithm of nisin concentration ranged 0.5~20 unitlml (12.5~500 ng/mf). Nisin activity of the pasteurized culture filtrates of L. lactis MLs was high at pH 2!3 but was inactivated completely at pH over 6.0. Nisin production of the L. lactis $ML_8$ cultured on LTB broth increased at late logarithmic phase and reached 10.5 unitlml after 16 hr. The cell growth of L. lactis LM 0230, a plasmid free and nisin sensitive strain, was inhibited on agar medium containing 7 unitlrnl of nisin, while L. lactis $ML_8$ showed high survival ability at 20 unitld of nisin. When 40 mM $Ca^[2+}$ ion was added to Elliker broth with 8 unitlml of nisin, the growth pattern of L. lactis $ML_8$ was similiar to that on control medium which did not contain nisin and $Ca^[2+}$ ion, and this suggested that $Ca^[2+}$ increased the nisin resistance of the L. lactis.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.174-180
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• 2011

Experiments were carried out to determine the role of Raf-1 kinase in the development of drug resistance to paclitaxel in v-H-ras transformed NIH 3T3 fibroblasts (Ras-NIH 3T3). We established a multidrug-resistant cell line (Ras-NIH 3T3/Mdr) from Ras-NIH 3T3 cells by stepwise increases in paclitaxel. Drug sensitivity assays indicated that the $IC_{50}$ value for drug-resistant Ras-NIH 3T3/Mdr cells was more than 1 ${\mu}M$ paclitaxel, 10- or more-fold higher than for the parental Ras-NIH 3T3 cells. Western blot and RT-PCR analysis showed that the drug efflux pump a P-glycoprotein were highly expressed in Ras-NIH 3T3/Mdr cells, while not being detectable in Ras-NIH 3T3 cells. Additionally, verapamil, which appears to inhibit drug efflux by acting as a substrate for P-glycoprotein, completely reversed resistance to paclitaxel in Ras-NIH 3T3/Mdr cell line, indicating that resistance to paclitaxel is associated with overexpression of the multidrug resistance gene. Interestingly, Ras-NIH 3T3/Mdr cells have higher basal Raf-1 activity compared to Ras-NIH 3T3 cells. Unexpectedly, however, the colocalization of Raf-1 and its negative regulator Spry2 was less observed in cytoplasm of Ras-NIH 3T3/Mdr cells due to translocation of Spry2 around the nucleus in the perinuclear zone, implying that Raf-1 may be released from negative feedback inhibition by interacting with Spry2. We also showed that shRNA-mediated knockdown of Raf-1 caused a moderate increase in cell susceptibility to paclitaxel. Thus, the results presented here suggest that a Raf-1-dependent pathway plays an important role in the development of acquired drug-resistance.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.905-913
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• 2014

Lj-RGD3, an RGD (Arg-Gly-Asp) toxin protein from the salivary gland of Lampetra japonica, exhibits antifungal activity against Candida albicans. Lj-RGD3 has three RGD motifs and shows homology to histidine-rich glycoprotein. We synthesised two mutant derivatives of Lj-RGD3: Lj-26, which lacks all three RGD motifs and contains no His residues; and Lj-112, which lacks only the three RGD motifs. We investigated the effects of the wild-type and mutated toxins on a gram-positive bacterium (Escherichia coli), a gram-negative bacterium (Staphylococcus aureus), and a fungus (C. albicans). rLj-RGD3 and its mutants exhibited antifungal but not antibacterial activity, as measured by a radial diffusion assay. The C. albicans inhibition zone induced by rLj-112 was larger than that induced by the other proteins, and its inhibitory effect on C. albicans was dose-dependent. In viable-count assays, the rLj-112 MIC was $7.7{\mu}M$, whereas the MIC of the positive control (ketoconazole) was $15{\mu}M$. Time-kill kinetics demonstrated that rLj-112 effectively killed C. albicans at $1{\times}$ and $2{\times}$ MIC within 12 and 6 h, respectively. Electron microscopy analysis showed that rLj-RGD3 and rLj-112 induced C. albicans lysis. Our results demonstrate a novel anticandidal activity for rLj-RGD3 and its mutant derivatives.

• International Journal of Oral Biology
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• v.30 no.3
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• pp.91-98
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• 2005

Gamma-aminobutyric acid (GABA) is known as an inhibitory neurotransmitter in the neurons of the central nervous system. However, its detailed action mechanisms in the rostral gustatory zone of the nucleus tractus solitarius (rNTS) have not been established. The present study was aimed to investigate the distribution, role and action mechanisms of GABA in rNTS. Membrane potentials were recorded by whole cell recordings in isolated brain slices of the rat medulla. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in the neurons in rNTS. The change in input resistance ws accompanied by response to a depolarizing pulse were diminished by GABA. Superfusion of the slices with either $GABA_A$ agonist, muscimol, $GABA_B$ agonist, baclofen or $GABA_C$ agonist, TACA, decreased input resistance and reduced the nerve activity in association with membrane hyperpolarization. It is suggested that inhibitory signals playa role in sensory processing by the rNTS, in that GABA actions occur through activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptor. These results suggest that GABA has an inhibitory effect on the rNTS through an activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptors and that the GABAergic inhibition probably plays an important role in sensory processing by the rNTS.

• Journal of Pharmacopuncture
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• v.14 no.1
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• pp.79-86
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• 2011

Objective : This study was performed to compare anti-inflammation, anti-oxidation and anti-bacterial effects of Cuscutae Semen(CS) extracted with two kinds of solvents, ethanol and distilled water. Methods : Two kinds of CS extractions were prepared 20, 50, 100 ${\mu}l/mg$. The cytotoxicity was measured by MTT assay in Raw 264.7 cell. The anti-inflammation effect was measured by inhibitory efficacy of NO Production in Raw 264.7 cell. The anti-oxidation effect was measured by DPPH Radical scavenging ability in HaCaT cell. The anti-bacterial effect was measured by inhibition zone diameter on Propionibacterium acnes. Results : 1. Two kinds(100 ${\mu}l/mg$) of CS extraction groups had 50% cytotoxicity in Raw 264.7 cell. 2. All of CS extraction groups were not showed significantly inhibitory effect on NO production. 3. All of CS extracted with ethanol only showed dose-dependently significantly scavenging effect of DPPH radicals. 4. Two kinds of CS extractions did not have a inhibitory effect on Propionibactrium acnes. Conclusion : Two kinds(100 ${\mu}l/mg$) of CS extraction groups have 50% cytotoxicity. Two kinds of CS extractions have not the inhibitory effect on NO production and Propionibactrium acnes. CS groups extracted with ethanol only have a significantly scavenging ability of DPPH radicals. This study suggests that CS extracted with ethanol was effective in anti-oxidation.

• Journal of Welding and Joining
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• v.18 no.2
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• pp.49-56
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• 2000

Recently developed Austenite stainless steel, 309L was used to overlay on 3Cr-1Mo-V-Ti-B steels, using Electroslag welding process, which wide electrodes were adopted. Transition region in welding interlayer relating to disbonding crack was investigated. Also, the effect of welding condition on the width of transition region and coarsening grains of the austenite were studied. 1) With increasing welding speed the width of martensite at transient region was increased, but the amount of delta ferrite in weld metal was reduced, being fine grained. 2) The form of martensite at the transition region was occurred by reversible transformation during cooling since the interdiffusion of Cr and Ni from weld metal and Fe and C from base metals at the transition region, causes to lowering the concentration of Cr and Ni at the transition region, leading to increasing Ms point. 3) With increasing welding speed, the grain of austenite formed at the welding interface was finer. With increasing welding current under the same welding speed, the grain size of the austenite was finer. At high current, original grain size of the austenite is coarse, but the austenite has fine grains because the austenite was transformed to martensite during cooling. 4) In the case of high welding speed, the width of martensite at the welding interface was increased, but the grain size of austenite at the welding interface was finer. This indicates that the inhibition of disbonding crack may be achieved through dispersening fine carbides in the gain boundary.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.49-57
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• 2009

Objectives：I want to examine the antimicrobial activity of Gwankeibujalijung-tang against Streptococcus pneumoniae 59 isolated from the mouth of a common cold patient. Methods： Antimicrobial activity was assayed through the hot water extract from Gwankeibujalijung-tang against Streptococcus pneumoniae 59 isolated from the mouth of a common cold patient. Results： The size of inhibition zone of Gwankeibujalijung-tang extract was 9.83 $\pm$ 0.11 mm. The optimal pH and temperature for the growth of isolated Streptococcus pneumoniae 59 were 7.0 and 37$^{\circ}C$, respectively. The minimum inhibitory concentration of Gwankeibujalijung-tang extract was 12 $\mu\ell$ and the antimicrobial activity of Gwankeibujalijung-tang extract was not destroyed by the heat (121$^{\circ}C$ for 15 min) and not affected by pH. Conclusions： Reviewing this experimental result, it appeared that Gwankeibujalijung-tang had efficacy against Streptococcus pneumoniae 59 isolated from the mouth of a common cold patient.