• Journal of Animal Science and Technology
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• 제48권4호
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• pp.595-602
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• 2006

본 연구는 우리나라 재래종인 한우로부터 초유를 얻어 Lf을 분리정제한 후 한우 Lf와 젖소 Lf의 항균활성을 확인하였다. E. coli O111및 기타 미생물에 대한 항균성은 젖소 Lf가 한우 Lf 보다 높았으며, 젖소 Lf 가수분해물도 한우 Lf 가수분해물보다 마찬가지로 높았다. MIC에서는 E. coli O111 경우 젖소 Lf가 1.5mg/ml, 한우 Lf은 2.75mg/ml이며 젖소 Lf 가수분해물은 0.12mg/ml, 한우 Lf 가수분해물은 0.25mg/ml로 항균성 실험과 동일하게 젖소 Lf 가수분해물의 항균활성이 더 높은 것으로 나타났다. 한편 Lf과 lysozyme의 첨가는 항균활성을 상승시키는 효과를 나타내었다.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.202-215
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• 1996

The purpose of this study was to an in estigate the antibiotic susceptibiliity of Actinoobacillus actinomycetemcomitans isolated from the subgingival plaque to adult periodontitis. Seven bacterial strains were tested for their susceptibility to 10 antimicrobial agents under disk diffusion method and broth dilution methold, Seven patients with deep pocket(6mm) were selected for this study. They had not taken antibiotics for 6 months and no history of dental treatment for 6 months and no history of dental treatment for 6 months before this study. The results were as follows : 1. For the antibiotic disk diffusion method, seven A. actinimycetemcomitans were tested with 10 antimicrobial agents which comprised penicillin, gentamycin, clindamycin, lincomycin, ampicillin, erythromycin, tetracycline, amikacin, chloramphenicol, and vancomycin. The sensitive antibiotics were tetracycline, vancomycin, and chloramphenicol and the resistant antibiotics were clindamycin, and lincomycin. The other antimicrobial agents were less active. 2. From the study of determination on the minimal inhibitory concentration(MIC) by broth dilution method, the MIC of tetracycline to seven strains of the A. actinomycetemcomitans was $0.5-1.0{\mu}g/ml$, that of clindamycin was $32{\mu}g/ml$. These data suggest that tetracycline may be valuable drugs in the elimination of A. actinimycetemcomitans from the patients with adult periodontitis

• 한국응용과학기술학회지
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• 제25권4호
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• pp.477-484
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• 2008

It is inevitable to use chemical germicidal agents like paraben, imidazolidinyl urea and phenoxyethanol to preserve the emulsions which is usually used in cosmetics. Although these chemical preservatives are good enough to reduce the microbiological contamination, they are irritative, allergenic to the skin. Several kinds of polyols are used in cosmetics as moisturizer and solvent. In this study, we evaluate the effects of polyols on anti-microbial activities, safety and resistant index. MIC(minimal inhibitory concentration) of polyols determined against 6 germs including Staphylococcus aureus. The order of MIC was PG $\cong$ DPG $\cong$ 1,3BG > HG > 1,2-PD > 1,2-HD $\cong$ 1,2-OD. The $2{\sim}3\;wt%$ of 1,2-HD(hexanediol) shows good anti-microbial effects in emulsions without allergenic response. Resistant index of 1,2-HD was less than 2 and this value was smaller than that of chemical preservatives. The mechanism of antimicrobilogical effect might be disturb the membrane of germs by investigating using electron microscope. Added to that, using this paradigm, low preservative contents, paraben-free system, and even preservative-free systems can be expected from these results.

• 대한수의학회지
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• 제39권1호
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• pp.96-103
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• 1999

The present study was carried out to investigate the prevalence of mycoplasmal pneumonia of slaugter pigs in Youngnam area during the period from 1995 to 1997. The prevalence and pathomorphology of gross lung lesions were studied from 682 slaughter pigs in 8 swine herds. Gross lesions of pneumonia were recorded in the lungs of 442(64.8%), from 367 out of them(83.0%) were diagnosed as mycoplasmal pneumonia. Microbiological examination was performed with 197 lungs with gross lesions of mycoplasmal pneumonia of slaughter pigs from 8 different swine herds. M hyopneumoniae, P multocida, A pleuropneumoniae, Streptococcus spp, Corynebacterium spp, and H parasuis were detected in 24. 4%, 48.2%, 2.5%, 11.2%, 3.6%, and 1.0% of the pneumonic lungs, respectively. A total of 48 strains of M hyopneumoniae was investigated for their in vitro susceptibility to 8 antibiotics. Among the drugs tested, lincomycin, oxytetracycline, tiamulin and tylosin showed the high activity in minimal inhibitory concentration(MIC) of $0.04{\sim}5{\mu}g/ml$ while erythromycin showed low activity in MIC values($1.25{\sim}{\geq}40{\mu}g/ml$).

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1397-1402
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• 2010

Papyriflavonol A (PapA), a prenylated flavonoid [5,7,3',4'-tetrahydroxy-6,5'-di-(${\gamma},{\gamma}$-dimethylallyl)-flavonol], was isolated from the root barks of Broussonetia papyrifera. Our previous study showed that PapA has a broad-spectrum antimicrobial activity against pathogenic bacteria and fungi. In this study, the mode of action of PapA against Candida albicans was investigated to evaluate PapA as an antifungal agent. The minimal inhibitory concentration (MIC) values were 10~25 ${\mu}g/ml$ for C. albicans and Saccharomyces cerevisiae, Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), and Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus aureus). The kinetics of cell growth inhibition, scanning electron microscopy, and measurement of plasma membrane florescence anisotrophy revealed that the antifungal activity of PapA against C. albicans and S. cerevisiae is mediated by its ability to disrupt the cell membrane integrity. Compared with amphotericin B, a cell-membrane-disrupting polyene antibiotic, the hemolytic toxicity of PapA was negligible. At 10~25 ${\mu}g/ml$ of MIC levels for the tested strains, the hemolysis ratio of human erythrocytes was less than 5%. Our results suggest that PapA could be a therapeutic fungicidal agent having potential as a broad spectrum antimicrobial agent.

• International Journal of Oral Biology
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• 제39권2호
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• pp.75-79
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• 2014

The aim of this study was to investigate antimicrobial effect of oleanolic acid (OA), ursolic acid (UA), and sophoraflavanone G against Enterococcus faecalis and Propionibacterium acnes, which are the major causative bacteria of endodontic infections. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC). The data showed that the OA, UA, and sophoraflavanone G had antimicrobial effect on all the strains use in the study with $16-64{\mu}g/ml$, $8-64{\mu}g/ml$, and $1-8{\mu}g/ml$ of MIC values, respectively. These results indicate that OA, UA, and sophoraflavanone G could be useful in the development of antiseptic solution for washing the root canal in endodontic treatments.

• 치위생과학회지
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• 제2권2호
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• pp.85-88
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• 2002

구강에서 분리한 세균에 대한 오미자 추출물의 증식저해를 조사하였다. 물을 추출용매로 사용할 때의 추출수율은 53.8%로 메탄올보다 높았고, 추출온도가 높은 것이 보다 유리하였다. 구강에서 분리된 세균의 생육에 대한 오미자 물추출물의 영향을 조사한 결과, 오미자 물추출물은 강한 항균력을 보였다. 구강에서 분리된 세균에 대한 오미자 물추출물의 최소저해 농도는 ${125{\sim}1000{\mu}g/ml}$의 범위인 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1827-1834
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• 2020

Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/ml, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40℃ compared to that at 35℃. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.380-388
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• 2012

북극 지의류로부터 서로 다른 5종의 극지 미생물을 분리하였고, 그들의 생리활성 물질들은 아세톤, 물, 클로로포름, 다이에틸에테르, 에탄올, 에틸아세테이트, 메탄올 및 페트롤륨 에테르 등 다양한 용매를 이용하여 균 배양액으로부터 추출되었다. 이러한 추출물들의 항균성은 Staphylcoccus aureus, Bacillus subtilis, Micrococcus luteus, Enterobacter cloacae, Pseudomonas aeruginosa 및 Escherichia coli 등 6종의 병원체에 대한 디스크 확산법과 최소억제농도 측정법에 의해 조사되었다. 여러 추출 샘플 중, Burkholderia sordidicola S5-$B^T$ (KOPRI 26644) 유사미생물 종의 에틸아세테이트 추출물이 표적박테리아에 대한 높은 항균활성을 나타내었다(억제대, 7-10 mm; 최소억제농도, $57.5{\rightarrow}1000{\mu}g/ml$). 또한, 다양한 추출 용매 중, 클로로포름 추출물에서 약하지만 분명한 활성을 나타내었다.

• 대한의생명과학회지
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• 제22권4호
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• pp.167-173
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• 2016

The broth microdilution technique used to measure the minimal inhibitory concentration (MIC) of natural compounds against bacteria is problematic: it is difficult to visualize bacterial growth due to the color of the natural compound. Therefore, the use of a colorimetric method with a redox indicator by broth microdilution can simplify it and increase its objectivity. This study evaluated the usefulness of the colorimetric method in measuring the MIC of Phellinus baumii against methicillin-resistant Staphylococcus aureus (MRSA). The inhibition in disc diffusion method was observed from $8,192{\mu}g/mL$ P. baumii in all 10 MRSA isolates examined; however, the MIC ranges of the 10 MRSA isolates was $512{\sim}2,048{\mu}g/mL$ by broth microdilution using a colorimetric method; with the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) indicator. In addition, the MIC of P. baumii by broth microdilution using MTT as indicator yielded excellent results. However, the 2, 3, 5-triphenyltetrazolium chloride (TTC) results could not be determined due to the color of the TTC indicator. The MICs of four antibiotics against MRSA using MTT or TTC were equal to those determined by visual interpretation. In conclusion, to evaluate the antibacterial effects of a natural compound, the broth microdilution technique is considered to be better than the disc diffusion method. Moreover, to resolve the problems caused by the colors of natural compounds, a colorimetric method such as that using MTT may be very valuable.