• 한국미생물·생명공학회지
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• 제47권1호
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• pp.54-63
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• 2019

Rubus coreanus Miquel (RCM), also known as Korean blackberry or bokbunja, is used as a South Korean traditional medicine to treat acne and inflammatory skin conditions. The antimicrobial activity of RCM root and its active compounds remain unclear. In this study, we prepared a 50% ethanol fraction, ethyl acetate fraction, and acid-treated ethyl acetate fraction (aglycone fraction) of RCM root, and evaluated antibacterial activities against the skin pathogens Staphylococcus aureus, Pseudomonas acnes, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. In a paper disc assay, all fractions of RCM root showed antimicrobial activities against the five skin pathogens. The ethyl acetate fraction displayed 6-, 12-, and 2-fold higher minimal inhibitory concentration (MIC) than the 50% ethanol fraction against S. aureus, E. coli, and P. acnes, respectively. The aglycone fraction displayed 2-fold higher MIC than methyl paraben against P. acnes, S. aureus, E. coli, and P. aeruginosa. The ethyl acetate fraction displayed a minimal bactericidal concentration (MBC) similar to that of methyl paraben, and the aglycone fraction showed 2- to 4-fold higher MBCs than those of methyl paraben. In particular, the ethyl acetate fraction was not cytotoxic and showed thermal stability after incubation at high temperatures ($60-121^{\circ}C$). Finally, the ethyl acetate fraction was separated and four components were identified: procyanidin C, propelagonidin dimer, ellagic acid, and methyl ellagic acid acetyl pentose. The compounds showed high antibacterial activities. These results suggest that RCM root is potentially applicable as a natural preservative in cosmetics.

• 한국축산시설환경학회지
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• 제12권3호
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• pp.107-114
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• 2006

본 연구는 젖소에 있어서 세족기 및 신개발 세족액의 적용효과를 구명하기 위하여 2004년 축산연구소 및 전문경영체농장 2개소에서 사육중인 홀스타인 착유우를 대상으로 신개박 세족기 및 세족액을 적용하여 다음과 같은 결과를 얻었다. 1. 유산동의 MIC와 MBC는 E. coli 및 Bacillus에 대해서 공히 0.31%로 나타났다. 신개발 세족액의 경우 E. coli에 대해서는 MBC가 5%로 나타났고 Bacillus에 대해서는 2.50%로 나타났다. 2. E. coli의 경우 5% 및 16% 농도에서 각각 95.69% 및 95.87%의 감소율을 나타내었고 Bacillus의 경우 5% 및 16% 농도에서 각각 99.5% 및 99.89%의 감소율을 나타내었다. 3. 30일동안 사용하였을 때 보행자세지수(locomotion score ; LS) 2, LS3, LS4 및 LS5의 경우 100%, 43.8%, 14.3% 및 0%의 정상회복율을 나타내었고 누적하여 60일동안 사용하였을 때 LS2, LS3, LS4 및 LS5의 경우 100%, 81.3%, 71.4% 및 50.0%의 정상회복율을 나타내었다. 4. 신개발 세족액을 사용하기 전과 후의 발굽장애 발생율에 있어서 사용 전에는 18.8%의 발생율을 보였으나 사용 후에는 1.5%의 발생율을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.816-823
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• 2022

The rapid spread of superbugs leads to the escalation of infectious diseases, which threatens public health. Endolysins derived from bacteriophages are spotlighted as promising alternative antibiotics against multi-drug resistant bacteria. In this study, we isolated and characterized the novel Salmonella typhimurium phage PBST08. Bioinformatics analysis of the PBST08 genome revealed putative endolysin ST01 with a lysozyme-like domain. Since the lytic activity of the purified ST01 was minor, probably owing to the outer membrane, which blocks accessibility to peptidoglycan, antimicrobial peptide cecropin A (CecA) was fused to the N-terminus of ST01 to disrupt the outer membrane. The resulting CecA::ST01 has been shown to have increased bactericidal activity against gram-negative pathogens including Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, and Enterobacter cloacae and the most affected target was A. baumannii. In the presence of 0.25 µM CecA::ST01, A. baumannii ATCC 17978 strain was completely killed and CCARM 12026 strain was wiped out by 0.5 µM CecA::ST01, which is a clinical isolate of A. baumannii and resistant to multiple drugs including carbapenem. Moreover, the larvae of Galleria mellonella could be rescued up to 58% or 49% by the administration of CecA::ST01 upon infection by A. baumannii 17978 or CCARM 12026 strain. Finally, the antibacterial activity of CecA::ST01 was verified using 31 strains of five gram-negative pathogens by evaluation of minimal inhibitory concentration. Thus, the results indicate that a fusion of antimicrobial peptide to endolysin can enhance antibacterial activity and the spectrum of endolysin where multi-drug resistant gram-negative pathogens can be efficiently controlled.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2129-2140
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• 2017

Silibinin is the major active component of silymarin, extracted from the medicinal plant Silybum marianum. Silibinin has potent antibacterial activity; however, the exact mechanism underlying its activity has not been elucidated. Here, we investigated the novel mechanism of silibinin against Escherichia coli. Time-kill kinetic assay showed that silibinin possess a bactericidal effect at minimal inhibitory concentration (MIC) and higher concentrations (2-and 4-fold MIC). At the membrane, depolarization and increased intracellular $Ca^{2+}$ levels were observed, considered as characteristics of bacterial apoptosis. Additionally, cells treated with MIC and higher concentrations showed apoptotic features like DNA fragmentation, phosphatidylserine exposure, and caspase-like protein expression. Generally, apoptotic death is closely related with ROS generation; however, silibinin did not induce ROS generation but acted as a scavenger of intracellular ROS. These results indicate that silibinin dose-dependently induces bacterial apoptosis-like death, which was affected by ROS depletion, suggesting that silibinin is a potential candidate for controlling bacteria.

• Journal of Periodontal and Implant Science
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• 제25권1호
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• pp.1-13
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• 1995

Chlorhexidine and Listerine are widely used in dentistry due to its effectiveness on plaque control and bactericidal action. The effects of these agent on chronic gingivitis and wound healing following surgical periodontal therapy in human has been favorable. Understanding the effects of chlorhexidine and Listerine on human gingival fibroblast will provide the rationale for its use during the healing process of periodontal surgery. The purpose of this study was to compare the effects of chlorhexidine and Listerine on human gingival fibroblast. Human gingival fibroblasts were cultured from the healthy gingiva on the extracted premolar of orthodontic patients. Human gingival fibroblast were trypsinized and cultured in growth medium added range of 0.0012-0.12% chlorhexidine and 1-100% Listerine mouth wash solution. The cell used in this study were between fifth to eighth passage number. The cell morphology were examined by inverted microscope and the cell activity were measured by MIT assay. The Morphology of gingival fibroblast added Chlorhexidine and Listerine at the concentration of all range were became globular and lost their cytoplasmic process. Our results indicate that a 0.0012 concentration of chlorhexidine and 1% concentration of Listerine were shows minimal cytotoxicity, but above these concentraion, there was a significant difference between the cell activity in the experimental group and control group(p

• 한국식품영양과학회지
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• 제26권1호
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• pp.54-59
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• 1997

토하젓의 원료인 새뱅이를 물, 에테르, 아세톤, 메탄올을 이용하여 순차적으로 추출한 다음 인체 및 식품에 유해작용을 하는 9종의 세균을 대상으로 항균성 시험을 실시한 결과는 다음과 같다. 진공동결건조한 새뱅이 분말의 용매추출 구간별 수율은 물추출구 52.0%, 에테르추출구 7.4%, 아세톤추출구 1.0%, 메탄올추출구 0.8%였다. 새뱅이의 용매추출구간별 항균성 검색 결과 시료 20$\mu\textrm{g}$/disk에 대하여 에테르추출구 8~12mm, 아세톤추출구 8~12mm, 메탄올추출구 7~9mm였으며 물 추출구는 항균성이 없었다. 새뱅이의 용매추출구간별 최저발육억제농도는 에테르추출구 250~5000$\mu\textrm{g}$/$m\ell$1, 아세톤추출구 125~500$\mu\textrm{g}$/$m\ell$, 메탄올추출구 250~500$\mu\textrm{g}$/$m\ell$ 였다. 새뱅이의 용매추출구간별 최저살균농도는 에테르추출구 2,500~10,000$\mu\textrm{g}$/$m\ell$, 아세톤추출구 1,250~10,000$\mu\textrm{g}$/$m\ell$, 메탄올추출구 5,000~10,000$\mu\textrm{g}$/$m\ell$로 나타났다.

• Journal of Applied Biological Chemistry
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• 제65권2호
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• pp.101-105
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• 2022

양파의 주요 flavonoid 성분인 quercetin에 대한 항균 활성은 일부 알려져 있으나, 식물 병원성 세균인 X. campestris와 E. carotovora에 대한 활성은 알려져 있지 않았다. 본 연구에서는 quercetin과 양파 추출물을 활용하여 이들 식물병원균에 대한 항균 활성과 농용 항생제인 streptomycin과의 synergistic 효과를 평가하였으나, E. carotovora에 대한 항균 활성은 없었다. 하지만, X. campestris에서는 다른 세균류에서 알려진 MIC보다 10배 이상 낮은 15.6 ㎍ mL^-1이었으며, MBC는 20.0 ㎍ mL^-1으로 X. campestris에 대해 높은 선택적 항균 활성을 확인할 수 있었다. 다만, 농업용 항생제로 사용중인 streptomycin과의 약효상승 효과는 없었다. 또한, quercetin은 양파껍질의 EtOAc와 EtOH 추출물로부터 확보할 수 있었으며, EtOAc 추출물에서 quercetin 순도가 높음을 확인하였고, 이에 따라 EtOH 추출물보다 2배 가량 높은 항균 활성(MIC = 500 ㎍ mL^-1)이 확인되었다.

• 대한수의학회지
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• 제29권4호
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• pp.493-501
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• 1989

A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens. Minimal inhibitory concentration(MIC) ranges of antimicrobial agents to C jejuni isolates were $${\leq_-}1.56$$ to $${\geq_-}100{\mu}g/ml$$ for erythromycin, rifampin, streptomycin and tetracycline, 50 to $${\geq_-}100{\mu}g$$ for cephalothin, $${\leq_-}1.56$$ to $50{\mu}g$ for ampicillin, $${\leq_-}1.56$$ to $25{\mu}g$ for kanamycin and nalidixic acid, $${\leq_-}1.56$$ to $12.5{\mu}g$ for chloramphenicol and gentamicin. Resistance rates of C jejuni were showed to in order of rifampin(84.7%), tetracycline(56.2 %), erythromycin(17.1%) and ampicillin(3.8%), all of the strains were sensitive to chloramphenicol, gentamicin and kanamycin, and the incidence rates of resistant C jejuni were highly frequent in pig isolates than chicken isolates. The drug resistance patterns of 87 chicken isolates C jejuni to 9 antimicrobial drugs were showed 12 patterns, and Sm Ra Tc(24.1%), Sm Ra(21.8%) and Ra Tc(14.9%) were relatively common, and also 21 pig isolates were showed 6 patterns and Em Sm Ra Tc(57.1%) were most frequent. The majority of the isolates showed multiple drug resistance. Bactericidal activity of 10% normal sera from healthy animals were examined for 60min at $37^{\circ}C$. C jejuni were decreased from 0.4 to 1.0 ${\log}_{10}$(p<0.01), and serum susceptibility were high in order of guinea pig, sheep, chicken and cattle sera. Serum sensitivity of C jejuni Ch-39 strain in increased serum concentation up to 10, 20, 40 and 80% were highly significant. In the normal animal serum, the number of Ch-39 strain were decreased from $1.8{\times}10^4/ml$ to $2.7{\times}10^3/ml$ after 60 min incubation(p<0.01), but the numbers were decreased to $6.6{\times}10^3/ml$ in the heat inactivated normal serum for 30 min at $56^{\circ}C$. Bactericidal activity was restored in the heat inactivated normal serum after the serum of complement source was added.

• 치위생과학회지
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• 제11권1호
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• pp.37-40
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• 2011

Triterpenoid saponins 유도체인 OA와 UA가 치아우식증 원인균종의 하나인 Streptococcus downei의 표준균주(ATCC $33748^T$) 및 임상균주(4주)에 대하여, 액체배지희석법을 이용한 MIC값 측정 및 time-kill 분석법을 통한 살균작용 유무를 측정하여 다음과 같은 결과를 얻었다. 1. S. downei ATCC $33748^T$ 및 S. downei 임상균주(4주)들의 OA 대한 MIC 값은 $8{\mu}g/ml$로 동일하였고, UA의 대한 MIC 값은 S. downei 표준균주와 임상균주 간에 차이가 있었다. 2. Time-kill 분석법을 실시한 결과 OA와 UA는 S. downei $33748^T$에 대하여 $2{\times}MIC$ (각각 $16{\mu}g/ml$과 $8{\mu}g/ml$) 이상의 농도에서 살균작용을 갖는다는 것을 알 수 있었다. 이상의 연구결과를 종합할 때, triterpenoid saponins 유도체인 OA와 UA는 뮤탄스 연쇄상구균 중 최근에 사람의 구강 내 치면세균막에 서식하는 것으로 밝혀진 S. downei,에 대해 살균제로 작용할 수 있음을 알 수 있었다.

• 한국임상수의학회지
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• 제25권5호
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• pp.346-354
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• 2008

The combined effects of EDTA-Tris and eighteen antimicrobial agents have been evaluated in eight clinically isolated methicillin-resistant bacteria (Staphylococcus aureus, Escherichia coli, Streptococcus uberis and Streptococcus agalactiae) from bovine mastitis. The antimicrobial activity was evaluated by measuring the minimal bactericidal concentration (MBC) for the antibiotics alone or in combination with EDTA-Tris in Mueller-Hilton broth and milk. Combined use of EDTA-Tris and antibiotics potentiated or antagonized activity of antibiotics against mastitic pathogens. Milk increased the antibiotic potency of erythromycin and spiramycin on S. aureus. Culture in milk changed patterns of EDTA-Tris combinational effects compared with that in standard Mueller-Hilton broth. Combined with EDTA-Tris in milk, synergic effects were observed in colistin, dihydrostreptomycin, kanamycin, erythromycin, gentamycin, oxytetracycline, streptomycin to E. coli, Str. uberis, and Str. agalactiae. However, significant antagonistic effects of milk on antibiotic susceptibility in combination with EDTA-Tris were noted in neomycin, streptomycin, penicillin, roxithromycin, and amoxicillin. This study indicates that combination therapy of EDTA-Tris with antibiotics in bovine mastitis should be used with caution because of the possible antagonistic effects of antibiotic combination with EDTA-Tris on mastitic pathogens. In addition, antibiotic susceptibility test in combination with EDTA-Tris in milk culture condition can be benefit in search of effective treatment regimen for some antibiotic-resistant bacteria of mastitis.