• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.40-47
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• 1997

New quinolones generally have a broad antibacterial spectrum against gram-positive, gram-negative, glucose-nonfermenting and anaerobic bacteria. Some of newly developed quinolones have potent activities against S. aureus including MRSA, S.pneumoniae including PRSP, B. fragilis, chlamydiae, mycoplasmas and mycobacteria as well, and show good activities against various strains resistant to antibacterial agents of other classes. Quinolones display postantibiotic effects in vitro and are bactericidal at concentrations similar to or twice that of the minimum inhibitory concentrations (MICs) for susceptible pathogens. In experimental murine infection models including systemic infections with various pathogens such as S. aureus, S. pyogenes, S. pneumoniae, E. coli and P. aeruginosa, quinolones have shown good oral efficacy as well as parenteral efficacy. Good oral absorption and good tissue penetration of quinolones account for good therapeutic effects in clinical settings. The target of quinolones are two structurally related type II topoisomerases, DNA gyrase and DNA topoisomerase IV. Quinolones are shown to stabilize the ternary quinolone-gyrase-DNA complex and inhibit the religation of the cleaved double-stranded DNA. Bacteria can acquire resistance to quinolones by mutations of these target enzymes. Mutation sites and amino acid changes in DNA gyrase and DNA topoisomerase IV are similar in the organisms examined, suggesting that the mechanism of quinolone resistance in the target enzymes is essentially the same among various organisms. Quinolones act on both the target enzymes to different degrees depending on the organisms or agents tested, and bacteria become highly resistant to quinolones in a step-wise fashion. Incomplete cross-resistance among quinolones in some strains of E. coli and S. aureus suggests the possibility of finding quinolones active against quinolone-resistant strains which are prevailing now. To find such quinolones, the potency toward two target enzymes and the membrane permeability including influx and/or efflux systems should be taken into account.

• 공업화학
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• 제7권6호
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• pp.1096-1104
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• 1996

새로운 항균제 및 항종양제를 합성하기 위하여 norfloxacin(8) 또는 ciprofloxacin(9)이 pteroic acid의 C-9위치에 치환되고 C-2 위치에 아미노기 대신 $CH_3$기가 치환된 새로운 pteroic acid 유도체 13a와 13b를 합성하였다. 이는 출발 물질인 norfloxacin과 ciprofloxacin의 piperazine N-4 위치에 2-amino-3-cyano-5-chloro-methylpyrazine(20)을 결합하여 1-alkyl(ethyl, cyclopropyl)-6-fluoro-1,4-dihydro-4-oxo-7-[[4-N- (2-amino-3-cyanopyrazin-5-yl)methyl]piperazin-1-yl]-3-quinolinecarboxytic acid(12a, 12b)를 합성하였다. 이를 각각 acetamidine. HCl과 고리화시켜 C-2 위치에 아미노기 대신 $CH_3$기가 치환된 새로운 pteroic acid 유도체 135와 13b를 각각 76.2%와 82.8%의 수율로 합성하였다. 그리고 이들 화합물에 대한 항균활성의 측정은 Pseudomonas aeruginosa ATCC9027을 포함하여 Gram-positive와 Gram-negative bacteria에 대하여 검토한 결과 합성한 화합물 13a와 13b는 일반적으로 norfloxacin보다 낮은 항균활성을 나타냈다.

• 멤브레인
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• 제32권1호
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• pp.23-32
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• 2022

세균은 분리막, 식품 포장 필름 및 바이오 의료 기기와 같은 다양한 미생물 막의 표면 위에서 자란다. 미생물 막의 성장은 엑소폴리사카라이드의 복잡한 구조 형성과 밀접한 관련이 있다. 미생물 막이 항균제의 대량 수송의 어려움으로 성장하게 될 경우 항균효과는 급격하게 감소한다. 항균 활동을 활성화하기 위해서 막의 표면은 살균 특성이 있는 기능성 물질들로 변형, 코팅 또는 고정한다. 한 가지 아이디어는 막 표면에 양전하 이온을 도입하는 것이다. 양전하 이온인 4차 암모늄 그룹의 존재는 마그네슘이나 칼슘같이 세균 세포벽에 존재하는 2가 금속이온을 대체할 수 있다. 세포막 파괴의 효능은 표면환경에서 사용 가능한 작용제들의 이동성에 달려있다. 이 리뷰에서는 4차 암모늄 그룹, 헬라민(helamine), 쌍성이온(zwitterion)과 같이 여러 살생물제를 포함하고 있는 막들을 다룬다.

• 한국의류학회지
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• 제20권3호
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• pp.512-518
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• 1996

Microcapsules containing 2, 4, 4'-trichloro-2-hydroxydiphenyl ether and perfumes were prepared by the coacervation using poly (vinyl alcohol) and crosslinking agents. Effects of dispersing agents, core materials, agitating speed and crosslinking agents on microcapsule size were investigated. The mean and deviation of microcapsule diameters decreased with increasing agitation speed. The diameters of m;crocapsules decreased with increasing dispering agent concentration at 6, 000 rpm of agitation speed, but it was not changed at 10, 000 rpm. The dispering effect of PVA is better than that of gum arabic. The slight increase in the diameter of microcapsule was observed when the amount of core material was increased. As the amount of crosslinking agent was increased, the diameter of microcapsule was decreased.

• Fisheries and Aquatic Sciences
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• 제18권3호
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• pp.241-247
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• 2015

In an effort to discover alternative phytotherapeutic antimicrobial agents to combat Streptococcus parauberis, a fish pathogenic bacterium, we evaluated the antibacterial activity of seaweed extracts in vitro. A methanolic extract of Ecklonia cava exhibited strong antibacterial activity against S. parauberis isolated from olive flounder Paralichthys olivaceus. Furthermore, the n-hexane soluble (Hexane) fraction of the E. cava methanolic extract exhibited the greatest antibacterial effect on S. parauberis strains with a minimum inhibitory concentration (MIC) ranging from 256 to $1,024{\mu}g/mL$. In addition, the MIC values of oxytetracycline against antibiotic-resistant S. parauberis were markedly reduced up to 64-fold in combination with the Hexane fraction, suggesting that the antibacterial activity of the antibiotic was restored when combined with the Hexane fraction. The interaction between both antibiotics and the Hexane fraction was assessed by the fractional inhibitory concentration (FIC) index. The Hexane fraction and oxytetracycline combination against antibiotic-resistant S. parauberis strains resulted in a median ${\sum}FIC$ range of 0.502 to 0.516. Thus, the synergistic ranges of median ${\sum}FIC$ < 1 were observed for all combinations of the Hexane fraction and oxytetracycline against S. parauberis. To the best of our knowledge, this is the first report indicating the efficacy of an E. cava extract against fish pathogenic bacterium S. parauberis.

• 대한본초학회지
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• 제30권5호
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• 생명과학회지
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• 제16권2호
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• pp.297-301
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• 2006

SDE연속추출장치로 추출, 농축한 어성초 휘발성 향기성분 추출물이 15종의 병원성 세균에 대한 항균활성을 측정한 결과는 다음과 같았다. 어성초의 추출물은 주로 Vibrio와 Bacillus속의 세균들에 대해 강한 항균활성을 나타냈고, S. aureus와 epidermidis, S. dysenteriae, C. xerosis, L. monocytogenes에도 비교적 높은 활성을 나타냈다. 하지만 E. coli, S. typhi, E. cloaceae, Y. enterocolitica와 같은 세균들은 어성초 휘발성 향기성분 농축물에 저항성을 가지는 것으로 나타났다. 어성초의 잎과 줄기에 대한 일반성분 중 수분, 조단백질, 조지방, 조회분은 잎에 많이 함유되어 있고 조섬유는 줄기에 많이 함유되어 있었다. 잎에서 9종의 유리아미노산이 검출되었고, 줄기에서는 8종의 유리아미노산이 총 8.81 mg/l00 g 으로 더욱 많이 검출되었다. 지방산조성을 분석한 결과 잎과 줄기에 linolenic acid (C18:3), linoleic acid (C18:2), palmitic acid (C16:0)이 다량 함유되어 있다. 무기성분 중 잎과 줄기에서 K의 함량이 가장 많았고 Ca, P, Mg, Fe, Zn, Cu의 순으로 많이 함유되어 있었다.

• KSBB Journal
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• 제15권3호
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• pp.226-231
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• 2000

원예산물의 저온저장중 부패방지를 위한 천연항균제 개발의 일환으로 식용 가능한 식물을 채집하여 E. coli K 12, B. subtilis K KCTC 1028 및 딸기부패균에 대한 항균활성을 조사하였다. 사철 쑥, 가죽나무 잎, 초피 잎, 적송 잎, 뽕 잎, 씀바귀, 마늘의 즙액은 E. coli와 B. subtilis에 대하여 높은 항균활성을 보였다. 이들 식물체 즙액으로부터 n-hexane, ethyl ace떠te, chloroform 및 물로 용매분획한 분획물로 항균성을 재검색한 결과, 사철쑥, 가죽나무 잎, 적송 잎, 씀바귀의 ethyl acetate 분획과 초피 잎과 마늘의 모 든 분획에서 비교적 높은 향균활성을 보였으며 가죽나무 잎의 ethyl acetate 분획 이 가장 높은 항균활성(6 nun)을 보였다. 한편 딸기의 저온저장중인 과육으로부터 두 종의 부패 세균을 분리하 여 각각 Staphylococcus sp. TG-IOI과 Staphylococcus sp. TG-I02 로 동정하였다. 이들 균주에 대한 항균성을 조사한 결과, 가죽나 무 잎의 ethyl acetate 분획에서 두 균주에 대하여 가장 높은 저 해효과(각각 6 mm, 7 nun)를 보였다.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1204-1209
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• 2010

We evaluated the antibacterial activities of selected edible Korean plant seeds against the food-borne pathogens Staphylococcus aureus KCTC1927, Escherichia coli KCTC2593, Salmonella typhimurium KCTC2054, and Bacillus cereus KCTC1014. While screening for antibacterial agents, we discovered that wheat germ extract contains 2,6-dimethoxy-1,4-benzoquinone (DMBQ) and is highly inhibitory to S. aureus and B. cereus. This is the first report of the antibacterial activity of wheat germ extract. We also investigated the antibacterial activities of the 1,4-benzoquinone standards 1,4-benzoquinone (BQ), hydroquinone (HQ), methoxybenzoquinone (MBQ), and 2,6-dimethoxy-1,4-benzoquinone (DMBQ). DMBQ and BQ were the most highly inhibitory to S. aureus and S. typhimurium, followed by MBQ and HQ. MICs for DMBQ and BQ ranged between 8 and 64 ${\mu}g/ml$ against the four foodborne pathogens tested. DMBQ and BQ showed significant antibacterial activity; the most sensitive organism was S. aureus with an MIC of 8 ${\mu}g/ml$. BQ exhibited good activity against S. typhimurium (32 ${\mu}g/ml$) and B. cereus (32 ${\mu}g/ml$). The results suggest that wheat germ extract has potential for the development of natural antimicrobials and food preservatives for controlling foodborne pathogens.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1707-1716
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• 2019

The development of new antimicrobial agents is essential for the effective treatment of diseases such as sepsis. We previously developed a new short peptide, Pap12-6, using the 12 N-terminal residues of papiliocin, which showed potent and effective antimicrobial activity against multidrug-resistant Gram-negative bacteria. Here, we investigated the antimicrobial mechanism of Pap12-6 and a newly designed peptide, Pap12-7, in which the 12^th Trp residue of Pap12-6 was replaced with Val to develop a potent peptide with high bacterial selectivity and a different antibacterial mechanism. Both peptides showed high antimicrobial activity against Gram-negative bacteria, including multidrug-resistant Gram-negative bacteria. In addition, the two peptides showed similar anti-inflammatory activity against lipopolysaccharide-stimulated RAW 264.7 cells, but Pap12-7 showed very low toxicities against sheep red blood cells and mammalian cells compared to that showed by Pap12-6. A calcein dye leakage assay, membrane depolarization, and confocal microscopy observations revealed that the two peptides with one single amino acid change have different mechanisms of antibacterial action: Pap12-6 directly targets the bacterial cell membrane, whereas Pap12-7 appears to penetrate the bacterial cell membrane and exert its activities in the cell. The therapeutic efficacy of Pap12-7 was further examined in a mouse model of sepsis, which increased the survival rate of septic mice. For the first time, we showed that both peptides showed anti-septic activity by reducing the infiltration of neutrophils and the production of inflammatory factors. Overall, these results indicate Pap12-7 as a novel non-toxic peptide with potent antibacterial and anti-septic activities via penetrating the cell membrane.