• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.88-91
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• 2007

Animal cells show different behaviors in response to the mechanical properties of the substrates. We hypothesize that the rigidity of the substrates also affects the bacterial motility and controls the colony dynamics. It is found that the colony size of Escherichia colis and Bacillus subtilis grown on the agar plates is correlated with agarose gel concentrations and thus with the substrate rigidity. High- resolution microscopic imaging reveals that bacteria in single colonies form different aggregation patterns on the agar plates with varying gel concentration. We measured the apparent diffusion coefficients in the agarose gel plates made with different gel concentrations. Mathematical modeling and quantitative imaging of dye dispersion in the agar plates suggest that there is a close connection between the diffusion rate and the colony size. Nanoscale pore structures and kinetic constraints in the porous media may have an effect on bacterial colony dynamics.

• 한국식품영양학회지
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• 제23권2호
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• pp.154-161
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• 2010

국화 정유의 식중독균에 대한 항균력을 검증하기 위해 국화 정유와 그 주성분인 camphor, chrysanthemyl alcohol, $\alpha$-pinene, $\gamma$-terpinene, ${\alpha}+{\beta}$-thujone를 10종 균주에 대하여 agar-well diffusion 분석법으로 생육 여부를 분서하였다. 실험 결과 국화 정유와 그 지표물질은 Gram 양성균과 음성균 모두에 대해서 탁월한 항균 효과가 나타났다. Agar-well diffusion 분석법 결과 국화 정유와 그 지표물질은 Gram 음성균보다 Gram 양성균에 대해서 강력한 활성을 나타내었다. 국화 정유의 minimum inhibitory concentration은 모든 균주에 대하여 5 ${\mu}g/m{\ell}$에서 균의 생장을 저해하는 효과가 나타났고, minimum bacteriocidal concentration은 S. choleraesuis와 L. monocytogenes에 대해서는 시험농도 내에서 사멸효과가 관찰되지 않았으나, 다른 균주에 대해서는 5~20 ${\mu}g/m{\ell}$에서 살균력이 나타났다. 또한 액체 배양중의 항균효과를 조사한 결과, 국화 정유와 그 지표물질은 24시간 동안 꾸준히 항균력이 지속되었다. 따라서 camphor, chrysanthemyl alcohol, $\alpha$-pinene, $\gamma$-terpinene, ${\alpha}+{\beta}$-thujone를 조성분으로 함유한 국화 정유성분은 10종의 식중독균에 대한 항균활성이 입증되어, 천연 항균제재로서 식품보존료로의 이용이 가능하리라 생각된다.

• Advances in environmental research
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• 제9권3호
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• 한국식품조리과학회지
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• 제26권2호
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• pp.206-213
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• 2010

In this study, the antibacterial activities of essential oil from Zanthoxylum schinifolium against four Gram-positive bacteria and six Gram-negative bacteria were investigated. The antibacterial activity of the oils was determined using the agar-well diffusion assay, MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). In particular, essential oil from Z. schinifolium showed higher antibacterial activity against Gram-positive bacteria than against Gram-negative bacteria. Essential oil from Z. schinifolium displayed large inhibition zones especially against Bacillus cereus (31 mm). At concentrations between 0 and $20\;{\mu}g/mL$ the oils showed an antibacterial effect against both Gram-negative and Gram-positive bacteria. The minimum inhibitory concentration (MIC) values against nine bacteria ranged from 1.25 to $5\;{\mu}g/mL$. The minimum bactericidal concentration (MBC) values against eight bacterial ranged from 2.5 to $20\;{\mu}g/mL$, except Shigella sonnei. Furthermore, our finding on the antibacterial activities of essential oils from Zanthoxylum schinifolium validated the use of this plant for medical purposes.

• Journal of Plant Biotechnology
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• 제47권1호
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• pp.100-106
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• 2020

Coix lacryma-jobi (Hanjeli) is known to posses anti-microbial properties. Therefore, phytochemical compounds of C. lacryma-jobi have been studied to produce novel antimicrobial agents as treatments against antibiotic-resistant bacteria.The objective of this study was to determine the phytochemical composition and antibacterial activity of the C. lacryma-jobi oil against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The phytochemical composition of the oil was determined via gas chromatography mass spectrophotometry (GC-MS). Moreover, agar disk and agar well diffusion were employed to screen the antibacterial activity of the oil. An agar well diffusion test was implemented to determinate MIC's (minimum inhibitory concentrations). Dodecanoic acid, tetradecanoic acid, 2,3-dihydroxypropylester, 1,3-dioctanoin, N-methoxy-N-methyl-3,4-dihydro-2H-thiopyran6-carboxamide, propanamide, 5-Amino-1-(quinolin-8-yl)-1,2,3-triazole-4-carboxamide, and pyridine were identified in the C. lacryma-jobi oil. The MIC value of the oil was 0.031 g/L and the MBC of the oil was 0.125 g/L effective in all test bacteria. Dodecanoic acid displayed inhibitory activity against gram-positive and gram-negative bacteria. Therefore, our research demonstrated C. lacryma-jobi (Hanjeli) oil exhibited antibacterial activity against E. coli, S. aureus, and B. subtilis. These research suggest that C. lacryma-jobi root oil could be used for medicinal purposes; however clinical and in vivo tests must be performed to evaluate its potential as an antibacterial agent.

• 셀메드
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• 제2권2호
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• pp.20.1-20.5
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• 2012

$Gynura$ $segetum$ (Lour.) Merr. ($Compositae$) is a well recognized medicinal plant in Indonesia and Malaysia. It is believed to have an anticoagulant effect and is used in treating snake-bites, inflammations and other skin afflictions. This study was carried out to evaluate the antimicrobial effects of $Gynura$ $segetum$ leaves extracts and its fractions. The chemical compositions of the active extracts were also determined. The antimicrobial activities of different solvent extracts of leaves of $Gynura$ $segetum$ were evaluated using the agar well-diffusion method. The Minimum Inhibitory Concentration (MIC) of the active subfractions was determined by the tube dilution method. Gas Chromatography-mass spectrometry (GC-MS) analysis was carried out to identify the chemical compositions of the active extracts. The ethyl acetate fraction and its subfraction E4 performed potent antimicrobial activities and fifteen known chemical constituents were identified by GCMS analysis as 4-vinylphenol, 1-tetradecene, phenol, 2,4-bis(1,1-dimethylethyl), 1-hexadecene, E-15-heptadecenal, hexadecanoic acid, 1,2-benzenedicarboxylic acid, dibutyl ester, 1-docosene, octadecanoic acid, 1-eicosene, cyclotetracosane, 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl)ester, butanedioic acid, monomethyl ester, niacin and 4-hydroxy-benzoic acid. The results of this study suggested a connection between the antimicrobial activities and the chemical structures. The plant may be used as a potential source for antimicrobial agents.

• Food Science and Biotechnology
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• 제15권3호
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• pp.437-440
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• 2006

To explore the possible usefulness of ${\beta}$-glucans as natural antioxidants, the antioxidant profiles of ${\beta}$-glucan, extracted from Saccharomyces cerevisiae KCTC 7911, and water soluble and insoluble mutant ${\beta}$-glucan, isolated from yeast mutant S. cerevisiae IS2, were examined by five different in vitro evaluation methods: lipid peroxidation value (POV), nitric oxide (NO), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power, and ${\beta}$-carotene diffusion assay. The antioxidant activities of all ${\beta}$-glucans evaluated in POV test were comparable to or better than that of the known antioxidant, vitamin C. Remarkably, the ${\beta}$-glucan and water insoluble mutant ${\beta}$-glucan possessed 2.5-fold more potent activity than vitamin C at a dosage of 2 mg. Although vitamin C showed 100-fold greater activity than all ${\beta}$-glucans in NO and DPPH tests for measuring the radical scavenging capacity, all ${\beta}$-glucans revealed higher radical scavenging activity than the known radical scavenger, N-acetyl-L-cysteine (NAC), in DPPH test. The water insoluble mutant ${\beta}$-glucan had 2.6- and 5-fold greater antioxidative activity than water soluble ${\beta}$-glucan in NO and DPPH tests, respectively, showing that all ${\beta}$-glucans were able to scavenge radicals such as NO or DPPH. While all ${\beta}$-glucans revealed lower antioxidant profiles than vitamin C in both reducing power activity and ${\beta}$-carotene agar diffusion assay, the ${\beta}$-glucan and water insoluble mutant ${\beta}$-glucan did show a marginal reducing power activity as well as a considerable ${\beta}$-carotene agar diffusion activity. These results confirmed the potential usefulness of these ${\beta}$-glucans as natural antioxidants.

• 한국미생물·생명공학회지
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• 제35권2호
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• pp.98-103
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• 2007

산란계의 분변으로부터 생균제 특성을 가진 유산균을 분리하기 위하여, 무작위 선발법과 agar well diffusion assay법을 사용하여 다수의 유산균을 1차 선발하였으며 이 중에서 대장균 억제능이 가장 우수한 CPM-7 균주를 분리하였다. 최종 선발된 CPM-7 균주는 형태학적 특징, 당 이용성 및 16S rRNA 서별 분석을 통하여 Lactobacillus salivarius CPM-7으로 동정되었다. L. salivarius CPM-7은 내산성 및 내담즙성이 우수한 것으로 나타났는데, pH 2에서 30분 동안 및 pH 3에서 6시간 동안 생균수가 거의 유지되었으며, bile salt 0.2%가 첨가된 MRS 배지에서 증식할 수 있었다. L. salivarius CPM-7은 a-galactosidase를 포함한 다수의 효소를 생산하는 것으로 확인되었으며, 돼지의 장 상피세포에 흡착할 수 있었다. L. salivarius CPM-7의 배양액 및 중화액은 자돈 설사를 유발하는 것으로 알려진 E. coli K88에 대한 강력한 억제능을 나타내었다.

• 미생물학회지
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• 제54권3호
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• pp.244-253
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• 2018

이 연구는 분리된 토양 세균에 의해 생성된 항균물질의 효과를 평가하기 위해 수행되었다. 2000여개의 세균 분리주 중 Paenibacillus elgii DS381이 여러 인간 피부 상재균과 병원성 세균에 대해 높은 항균활성을 나타내었다. DS381 균주는 agar well diffusion test에서 모든 대상 세균과 효모에 대해 15.3~26.0 mm 직경의 저해대를 형성하였다. DS381이 생성한 항균 펩티드는 모든 대상 미생물에 낮은 최소저해농도 (0.039-5.000 mg/ml)를 나타내었다. DS381 균주는 lipopeptide 같은 생물계면활성제 생산을 나타내었는데, 배양 상등액의 표면장력을 60.0에서 40.3 mN/m으로 낮추었다. DS381은 또한 $1.56{\pm}0.13U/ml$의 chitinase 활성도 나타내었다. 이 결과들은 P. elgii DS381이 일부 중요한 인간 피부 상재균과 병원성 세균에 대한 효율적인 생물제어제로 사용될 수 있음을 가리킨다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.740-744
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• 2003

The antimicrobial substance produced by Lactobacillus bulgaricus was inactivated by pretense, which confirmed it as a bacteriocin and referred to 'bulgaricin HJ'. The bulgaricin HJ showed the inhibitory activity against mastitis pathogens, gram-positive and gram-negative bacteria. The optimal conditions for the production of bulgaricin HJ were at the temperature of $30^{\circ}C$ and 10 h after cultivation of L. bulgaricus. Staph. and Strep. agalactiae, common bovine mastitis pathogens, were treated with bulgaricin HJ by the agar well diffusion method and showed antimirobial activities to the bovine mastitis pathogens. The activity of the bulgaricin HJ was maintained at pH 6-7 and $100^{\circ}C$ for 60 min against the mastitis pathogens. The bulgaricin HJ was determined as class IV bacteriocin by various enzyme treatments. Colony forming units analysis with indicator strains by the treatments of bulgaricin HJ indicates that the mode of bacteriocin action was bactericidal rather than bacteriostatic.