• Journal of Microbiology and Biotechnology
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• 제19권2호
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• pp.204-207
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• 2009

We investigated novel antibacterial and synergistic activities of isocryptomerin isolated from Selaginella tamariscina. Isocryptomerin showed potent antibacterial activity against Gram-positive and Gram-negative bacterial strains including clinical isolates of antibiotic-resistant species such as methicillin-resistant Staphylococcus aureus(MRSA). Additionally, we further investigated the synergistic activity of isocryptomerin with a conventional antibiotic against MRSA. The result indicated that isocryptomerin had considerable synergistic activity in combination with cefotaxime. In summary, the present study suggests that isocryptomerin may have potential as a novel therapeutic agent for treatment of infectious diseases by not only human pathogenic bacteria but also multidrug-resistant bacteria.

• 한국미생물·생명공학회지
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• 제22권1호
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• pp.52-58
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• 1994

The induced antibiotic peptides were isolatde from the white-spotted folwer chafer, Protaetia brevitarsis by injection of E. coli suspension to the larvae of the insect. The antibacterial activity of the peptides were assayed by the plate growth ingibition method, and were purified by ion-exchange chromatography, reversed-phase HPLC, ion-exchange HPLC and SDS-PAGE etc. The peptides were estimated as 9 kDa in molecular weight and named Protaecin I and Protaecin II, respectively. Protaecin I and II have strong antibacterial activities against Gram-positivie and/or Gram-negative bacteria, and they are stable in the heat treatment and in the range of pH 2-12.

• Archives of Pharmacal Research
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• 제27권9호
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• pp.885-892
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• 2004

Due to the rapidly growing number of resistant strains of bacteria, the search for antibacterial agents with new modes of action will always remain an important and challenging task. Thus, the reaction of 2-substituted or. unsubstituted-4-(4-acetylanilino)-5,6,7,8-terahydrobenzo［b］ thieno［2,3-d］pyrimidine derivatives 1-3 with the hydrazine derivatives, semi and / or thiosemi-carbazides, provided the corresponding hydrazones 4-6 and semi and/or thiosemicarbazones 7-9. Claisen-Schmidt condensation of compounds 1 or 2 with the appropriate aldehyde yielded the chalcones 10, 11 which, when treated with hydroxylamine hydrochloride gave rise to the isoxazoline-containing compounds 12, 13. Furthermore, reacting the respective chalcones 10, 11 with different hydrazines, urea and/or thiourea, furnished compounds 14, 15, 16, and 17 respectively. Representative compounds were tested for their antimicrobial activity against Candida Albicans and certain gram-positive and gram-negative bacteria. Their MICs were then determined. Compound 15e, showed a broad spectrum of activity while most of the other com-pounds showed varying antimicrobial activity.

• Animal cells and systems
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• 제12권1호
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• pp.41-46
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• 2008

A bacterium strain called Bacillus coagulans was isolated from an industrial wastewater drainage and selected for its antimicrobial activities against bacteria and fungi. Characterization studies strongly suggested that this strain is Bacillus coagulans. Antimicrobial activity was found against gram-positive, gram-negative bacteria and yeast strain. Maximal activity was observed after 24 h when incubated at $30^{\circ}C$ and pH 8. The activity was found to be stable at $75^{\circ}C$ for 30 min and at pH range of 2-12. Analysis of the antimicrobial compound by SDS-PAGE suggested a molecular mass of approximately 7.5 KDa. The substance was characterized as a bacteriocin, because of its proteinaceous nature and low molecular weight. Our bacteriocin could potentially be used as a food preservative, because of its thermostable property and broad antimicrobial spectrum.

• Advances in Traditional Medicine
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• 제8권4호
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• pp.374-379
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• 2008

In the present study, various extracts of Clerodendrum infortunatum leaves have been studied for its anthelmintic, antimicrobial and antipyretic activities. In the anthelmintic and antipyretic study it was observed that the benzene extract was more potent than the other two extracts (ethanol and aqueous) even though all the three extracts were endowed with both the properties. The study reveals antimicrobial activity of the extracts against the tested strains of microorganisms between concentration ranges of $75\;{\mu}g/ml$ and $350\;{\mu}g/ml$ and shows effectiveness more against gram-positive bacteria than the gram-negative bacteria.

• 한국지역사회생활과학회지
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• 제26권4호
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• pp.697-705
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• 2015

This study investigates antimicrobial effects of food-borne pathogens and the antioxidant activity of Torreya nucifera extract. The growth of food-borne pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was inhibited by the extract. The antimicrobial activity of the extract was highest for Staphylococcus aureus among seven gram-positive bacteria and for Pseudomonas aeruginosa among six gram-negative bacteria. The extract exhibited slightly lower DPPH radical-scavenging activity, but its ABTS radical-scavenging activity was higher than that of ${\alpha}$-tocopherol. The results demonstrate the extract's antimicrobial effects on food-borne pathogens as well as potent antioxidant capacity and suggest that Torreya nucifera may be used as a natural antibacterial agent and an effective antioxidant in food.

• Advances in Traditional Medicine
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• 제7권4호
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• pp.385-389
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• 2007

We undertook the present study to evaluate different pharmacological as antioxidant, antibacterial and cytotoxic activities of the crude ethanolic extract of Momordica charantia (Family: Cucurbitaceae) leaves. The antioxidant property of the extract was assessed by 1, 1-diphenyl-2-picryl hydrazyl free radical scavenging assay. The extract showed antioxidant activity where $IC_{50}$ was about ${\sim}500{\mu}g/ml\;and\;IC_{50}$ was about ${\sim}10{\mu}g/ml$ for standard drug ascorbic acid. The extract showed a broad spectrum of antibacterial activity against all the tested gram positive and gram-negative bacteria where Staphylococcus epidermidis, Staphylococcus aureus, Salmonella typhi and Shigella dysenteriae were prominent. And the zones of inhibition were ranging from 8-15 mm for all the tested bacteria. Its cytotoxic property was evaluated by brine shrimp lethality bioassay. The extract showed significant lethality and the $LC_{50}$ value was $20{\mu}g/ml$.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.217-221
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• 2000

In previous study, marine actinomycetes producing the antibiotics were investigated to invent new antibiotics from east coast of Korea. The optimum growth conditions of Streptomyces sp. NS 13239 were $28^{\circ}C$, pH 7.0 and $3\%$ of NaCl concentration in various media. Streptomyces sp. NS 13239 showed strong antimicrobial activity against gram-positive bacteria, specially Methicillin resistant Staphylococcus aureus (MRSA), but just weak antimicrobial activity against yeasts and mold. On the other hand, it did not show antimicrobial activity against gram-negative bacteria. The optimum conditions for producing antibiotics were almost consistent with optimum growth conditions except carbon source and nitrogen source.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.861-864
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• 2008

Twenty eight bacterial strains were isolated and identified from human oral cavities. These strains were identified as genus 9 Moraxella, 2 Neisseria, 1 Proteus, 6 Bacillus, 5 Staphylococcus, 3 Branhamella and 2 Enterobacter. Two genuses are Gram-positive and four genuses are Gram-negative. In order to search for antimicrobial substances from natural plants, twenty one plant materials being made of perilla leaf as well as spices including garlic and ginger were used. The effects of these plant juices on the growth of oral bacterial strains were investigated. Only garlic juice inhibited the growth of seventeen bacterial strains belonging to 6 kinds of genus.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.493-496
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• 2002

용균작용을 하는 lysozyme을 난백으로부터 분리하기 위해 이온교환크로마토그래피를 사용하였다. 용출시에 gradient를 걸어준 결과 젤과 약하게 결합된 단백질과 강하게 결합된 단백질이 분리되어 나옴을 SDS-PAGE와 Lowry methode를 통하여 알 수 있었다.