• Korean Journal of Microbiology
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• v.19 no.3
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• pp.103-107
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• 1981

Increasing the concentration of the nonionic surfactants the solubility of methyl paraben was increased. This is called the solubilization phenomenon and caused inactivation of the preservatives used. The MICs(minimum inhibitory concentrations) on E. coli were increased at the same time. So the relation between the solubility and the mic could be expressed as $S-S_0=R^{\prime}/R^{\prime\prime}\;(M-M_0)$ and in this case $R^{\prime}/R^{\prime\prime}$ was about 2.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.149-154
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• 2018

This article intended to examine the anti-plaque activity of 4 essential oils of Lavender, Tea tree, Eucalyptus, Lemongrass against Streptococcus mutans. In the results of measuring the anti-plaque effect against Streptococcus mutans, Minimum anti-adhesive concentration of Lavender oil was 1.0% and that of Tea tree, Eucalyptus, lemongrass essential oils was 0.5 %. Also, it was confirmed that the essential oils have the effect of inhibiting acid generation by Streptococcus mutans. It was confirmed that pH of the concentration was lowered by the acid generation under the MAC by measuring pH of the solution after incubating Streptococcus mutans and the essential oils in the thermostatic bath varying their concentration. From these results, the essential oils, particularly, Tea tree, Eucalyptus, Lemongrass essential oils are the natural material inhibiting the plaque generation and the potential that they can be used to develop the oral care products was confirmed.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.265-270
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• 2017

A key virulence factor for urinary tract pathogens is the enzyme urease, which catalyzes the hydrolysis of urea into ammonium ions and carbonic acid. Urease activity plays an important role in the pathogenesis of urinary tract infection. In this study, the inhibitory effect of zerumbone against six urease-producing bacteria (Klebsiella oxytoca, K. pneumoniae, Morganella morganii, Proteus mirabilis, P. vulgaris, and Staphylococcus saprophyticus) and their urease activities were evaluated. The results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests showed that zerumbone had antibacterial effect against these six urease-producing bacteria. The MIC and MBC of zerumbone ranged from 0.5 to 2 mM and 1 to 4 mM, respectively. In the urease inhibitory assay, zerumbone showed better urease inhibition ($56.28{\pm}2.45-37.83{\pm}3.47%$) than the standard urease inhibitor, acetohydroxamic acid ($40.46{\pm}1.94-22.99{\pm}3.53%$). However, zerumbone did not affect the levels of the urease subunit. These results clearly indicated that zerumbone has antibacterial potential against urease-producing bacteria and possesses excellent bacterial urease inhibition properties.

• Korean Journal of Legislative Studies
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• v.25 no.3
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• pp.69-96
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• 2019

This paper is written to suggest several recommendations for South Korea to deter and defend North Korean nuclear threat, when North Korea does not seem to give up its nuclear weapons and the US's extended deterrence including the nuclear umbrella could remain uncertain. For this purpose, it explains key options regarding nuclear deterrence and defense by non-nuclear weapon state. It evaluates the current status of South Korean non-nuclear preparedness against North Korean nuclear threat and provides some recommendations to improve the preparedness. As a result, this paper concluded that South Korean non-nuclear preparedness against North Korean nuclear threat was not that reliable. The preparedness has weakened since the South Korean effort to denuclearize North Korea through negotiations in 2018. In this sense, South Korea could have serious problems in protecting its people from North Korean nuclear threat if the US promise of extended deterrence is not implemented. South Korea should focus on its decapitation operation to North Korean highest leaders in case of North Korean nuclear attack based on a minimal deterrence concept. It should be prepared to conduct preventive strikes instead of preemptive strikes due to North Korea's development of solid fuel ballistic missiles. It should integrate its Ballistic Missile Defense with that of the US forces in Korea. South Korea should make a sincere effort for nuclear civil defense including construction of nuclear shelters.

• Journal of Veterinary Clinics
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• v.27 no.3
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• pp.252-256
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• 2010

Bovine mastitis, defined as an inflammation of the mammary gland, is usually associated with bacterial infection. Thus, treatment and control of mastitis relies primarily on antimicrobial therapy. This study investigated the bactericidal actions of silver ion against causing various bovine mastitis pathogens. Minimal inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and bactericidal activity times and concentrations of silver ion against pathogens were determined. The effect of silver ion on bacterial morphology was studied by scanning electron microscopy (SEM). The MICs and MBCs of silver ion for various bacteria strains ranged from 1.9-15.6 ${\mu}g$/ml. SEM images indicated formation of a pit, distortion and disruption of cell walls in silver treated Staphylococcus aureus and Escherichia coli. The results demonstrate that silver ion has a bactericidal capacity against causing various pathogens of bovine mastitis and suggest that silver ions may be exploitable as a therapeutic/preventative tool of bovine mastitis.

• Korean Journal of Oriental Medicine
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• v.12 no.1
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• pp.69-75
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• 2006

This research was aimed to search for natural antimicrobial agents that are sefe for humans and specific for oral pathogens. Acanthoic was isolated from the chloroform fraction of methanol extract of Acanthopanax koreanum $N_{AKAI}$ and its structure were elucidated by 13-NMR, 1H-NNR and ESIMS. Antibacterial activity of acanthoic acid was investigated by the minimum inhibitory (MIC) and minimun bactericidal (MBC) concentration. MIC/MBC of acanthoic acid against Streptococcus mutans $N_{AKAI}$ causing dental caries was determined to be $2/4\;{\mu}g/mL$, which was much lower than these of other natural antimicrobial agents such as $8/16\;{\mu}g/mL$ of sangurinarine and $250/500\;{\mu}/mL$ of green tea extract, $500/600\;{\mu}g/mL$ of thymol and borneol. Acanthoic and significantly inhibited the growth of other cariogenic bacteria such as Streptococcus sobrinus $N_{AKAI}$ and Streptococcus sanguis $N_{AKAI}$, and Streptococcus gordonii $N_{AKAI}$ in the MIC range of $4{\sim}32\;{\mu}g/mL$. My finding suggests that acanthoic acid could be employed as a potential antibacterial agent for preventing dental caries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.127-132
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• 2001

This research was conducted to investigate the antimicrobial activities of ethanol extracts from omija against the 12 icroorganism including bacteria, yeast and mold. The extracts inhibited the growth of bacteria, but not yeast or mold. Minimum bactericidal concentration (MBC) of B. subtilis and S. aureus was 1.6~3.2 mg/mL, and those of gram(-) bacteria, including E. coli, were 6.3~12.5 mg/mL. Growth of B. subtilis and S. aureus were retarded by adding 900 ppm and 300 ppm of ethanol extracts. Anthimicrobial activity of the ethanol extracts was not destroyed by heating. In comparison of endocarps extracts with the ethanol from the seed extracts, the ethanol extracts of endocarps showed the high antimicrobial activity.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.375-383
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• 2006

사람치주인대섬유모세포(human periodontal ligament fibroblast, PDLF)의 기능 손상과 클로르헥시딘(Chlorhexidine, CHX)의 세포독성에 관한 분자적인 기전은 최근까지도 불명확하다. 이 연구의 목적은 PDLF에 의한 골결절 형성에 있어서 CHX의 효과를 평가하고, 치주수술후에 치주병원균의 최소억제농도(minimal inhibitory concentration, MIC)를 평가하고자 하였다. CHX의 세포독성을 평가하기 위해서 MTT assay법을 실시하였다. CHX은 0.12%에서 0.00012%까지, 즉 10-1000배로 희석시킨 후 30, 60, 120초 동안 PDLF에 적용되었고, 석회화된 결절은 alizarin red 용엑에 염색되었다. 치주병원균에 대한 CHX의 MIC가 평가되었다. 이 연구 결과, 세포생존율 검사에서는, 단지 0.12% CHX 에 노출되었던 세포들만 세포 증식 소견을 다소 나타내었다. 모든 CHX 농도(0.12%-0.00012%)에서 PDLF에 의한 골결절 형성은 의미있는 감소를 나타내었다. 또한 치주병원균에 대한 CHX의 MIC는 0.0012%로 나타났다. PDLF의 골결절 형성에 영향을 주는 농도(0.00012%)는 세포독성을 나타내는 농도(0.12%)보다 더 낮은 농도를 보였고, 치주병원균의 최소억제에 필요한 농도는 0.0012%로 나타났다. 이런한 결과들은 통상적으로 상용되는CHX이 PDLF에 의한 골결절 형성에 있어서 영향을 미칠 수 있음을 시사하였다.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.254-259
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• 2007

The control of enzymic browning in potato slices by the use of citrate and phosphate buffer at different pH values and concentration was investigated. Minimally processed potatoes were stored at $5^{\circ}C$ and $20^{\circ}C$ followed by dipping in distilled water, citrate buffer (pH $3.0{\sim}5.0$) and phosphate buffer (pH $5.0{\sim}7.0$). The color characteristic was measured after storage at $5^{\circ}C$ and $20^{\circ}C$ for 24 hours. Treatment effectiveness was greatly improved by reducing pH and temperature. The citrate buffer was more effective than phosphate buffer in the browning inhibitory capacity. The citrate buffer (pH 3.0) showed the most anti-browning effect in this condition and more effective inhibition of browning by increasing concentration of treatment solution. The phosphate buffer (pH 5.0) treatment showed more effectiveness than concentration of 0.5 M of citrate buffer treatment.

• Journal of Aquaculture
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• v.14 no.3
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• pp.157-163
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• 2001

The antibacterial effect of fish diet soaked in the extract of Salvia miltiorriza was tested to determine its levels of antibacterial activity, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC). The extract showed strong activity against gram positive bacteria, but was weak against gram negative bacteria. Concentration levels of 13.4~40.3 and 67.2~403.0 $\mu\textrm{g}$/ml were determined as the MIC and MBC, respectively. However, levels above 403.0 $\mu\textrm{g}$/ml was neither bacteriostatic nor bactericidal against Edwardsiella tarta, a gram negative strain. The fish diet, soaked in the extract of Salvia miltiorriza, inhibited the growth of all strains of Streptococcus genus and Vibrio anguillarum. The relationship formula between weight of fish diet and Salvia miltiorriza extract absorbed into the fish diet was Y＝2.4953X＋3.3276 ($R^2$= 0.9999). The antibacterial activity of the fish diet, soaked in the extract, was stable from 10 to 35$^{\circ}C$ during the storage period of 28 days.