• Applied Biological Chemistry
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• 제41권3호
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• pp.258-263
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• 1998

본 연구는 polyyne계 항생물질의 분자 구조와 활성관계를 체계적으로 살펴본 최초의 보고로서 친수성기와 tetrayne 부분을 갖고 있는 화합물이 강한 항균활성을 가질 것이라는 결과를 얻었다. 이와 같은 선행 연구결과를 바탕으로 보다 개선된 활성을 갖는 화합물을 합성하기 위하여 tetrayneol 부분 구조를 가지는 novel한 polyhydroxy 화합물인 당류 유도체를 합성하고 항균성과 구조와의 관계를 검토하였다.

• 한국식물병리학회지
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• 제13권1호
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• pp.63-68
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• 1997

In the screening of antiviral materials produced by actinomycetes, an isolate named B25 was fond to produce an antibiotic substance ASA, which showed a strong inhibitory activity against tobacco mosaic virus (TMV) infection. ASA was purified from culture broth of B25 by silica gel column chromatography, preparative TLC, and reversed phase HPLC. Also MS, IR, UV spectrum, and melting point of ASA were determined and analysed. ASA was white powder soluble in dimethyl sulfoxide, chloroform, and ethyl acetate, having absorption peaks at 223 and 328 nm in UV-VIS spectrum, and had a molecular weight of 548. ASA showed strong inhibitory effect on TMV infection when it was applied as a mixture of TMV to the upper surface of leaves of a local lesion host (Nicotiana tabacum c. Xanthi-nc). It also showed antimicrobial effect against yeast and some phytopathogenic fungi.

• Journal of Microbiology and Biotechnology
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• 제5권6호
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• pp.346-352
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• 1995

For isolation of antibiotic-producing bacteria antagonistic to Fusarium oxysporum, a total of 327 microorganisms were screened from sesame-growing soils collected at various locations in Korea by the modified Herr's triple-agar-Iayer technique. Among the 36 bacterial isolates further screened by the dual culture test on tryptic soy agar, 10 were tested to show their antagonistic activity against 14 plant pathogenic fungi. Bacterial culture filtrates were shown either to inhibit some phytopathogenic fungal growth or to suppress F. oxysporum infection of sesame plants maintained in the green house. An isolate, B23, with the most prominent antagonistic activity was identified as Bacillus subtilis.

• Natural Product Sciences
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• 제19권1호
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• pp.61-65
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• 2013

A bioassay-guided fractionation of the extract of the fungus Paecilomyces variotii, which was derived from the giant jellyfish Nemopilema nomurai, led to the isolation of antibacterial compounds viriditoxin and its monomeric subunit semi-viriditoxin. Viriditoxin showed significant antibacterial activity against several marine fish and human pathogens including MDR strains. Significant potencies against resistant pathogens such as VRE Enterococcus faecium, VRE Enterococcus faecalis, and MRSA were highly interesting. Viriditoxin also showed notable antibacterial activity against the fish pathogen Streptococcus iniae. Its potency was over 100-fold higher than oxytetracycline which is employed as a general antibiotic for aquaculture.

• 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.

• 한국균학회지
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• 제23권1호통권72호
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• pp.37-45
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• 1995

석유에테르, 80% 에탄올 및 물로 추출하여 얻은 204개의 추출물 각각에 대해서 8종류의 곰팡이에 대한 항균활성을 검색하였다. 그 결과 Abortiporus DGU-L6 버섯의 석유에테르 추출물은 Microsporum gypseum균에 대하여 항균활성을 나타내었고, Cortinarius DGU-L51 버섯의 알콜추출물에서는 A. niger, Marasminus DGU-L67 버섯의 알콜 추출물 및 물 추출물에서는 A. niger(KCTC 2118)과 A. versicolor(KCTC 2120) 균에 대해서 항균활성을 나타내었다. 그리고 Hetero DGU-L25 버섯의 석유에테르 추출물은 8종류의 곰팡이에 대해서 모두 항균활성을 나타내었고, 이중 특히 모창을 유발하는 균에 대해서는 40 mg/ml의 아주 낮은 최소억제농도 값을 나타내었다.

• Fisheries and Aquatic Sciences
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• 제16권2호
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• pp.79-84
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• 2013

In an effort to discover an alternative antibiotic for treating infections with methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas sp. UJ-6, a marine bacterium that exhibited antibacterial activity against MRSA, was isolated. The culture broth and its ethyl acetate extract exhibited bactericidal activity against MRSA. The extract also exhibited antibacterial activity against gram-negative bacteria, which were not susceptible to vancomycin. The treatment of MRSA with the extract resulted in abnormal cell lysis. The extract retained >95% of its anti-MRSA activity after heat treatment for 15 min at $121^{\circ}C$. Thus, although most antibiotics are unstable under conditions of thermal stress, Pseudomonas sp. UJ-6 produces a heat-stable anti-MRSA substance. The results of this study strongly suggest that Pseudomonas sp. UJ-6 can be used to develop a novel, heat-stable, broad-spectrum antibiotic for the treatment of MRSA infections.

• BMB Reports
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• 제31권4호
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• pp.328-332
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• 1998

The 8-hydroxyisocoumarin, named Centipedin, which has a significant antibiotic activity, was separated and solubilized with organic solvents, such as diethyl ether from centipede Scolopendra subspinipes multilans L. Koch. The Centipedin was purified by silicic acid column and high S cation exchange chromatography followed by reverse-phase HPLC. It was confirmed that Centipedin has a potent antibiotic effectiveness against Gram-negative Klebsiella pneumoniae ATCC 8308. The results showed that Centipedin blocks both DNA replication and RNA transcription during the growth of this pathogen in vivo. The biosynthesis of antibiotic 8-hydroxyisocoumarin was studied in vivo by feeding $[^{14}C]-labelled$ compound as a precursor to live centipede, in which $[^{14}C]acetate$ was the most efficiently incorporated into the Centipedin within 30 h after injection. Also, in vitro study on the biosynthesis of Centipedin showed that efficient incorporation of $[^{14}C]acetate$ occurred at pH range 5.0-7.0 for 10 h incubation and decreased significantly after then. It is suggested that 8-hydroxyisocoumarin is one of the defense compounds acting on bacterial infection in Scolopendra subspinipes.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.635-638
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• 2004

An ATP-binding-cassette (ABC) transporter gene in the cephabacin biosynthetic gene cluster of Lysobacter lactamgenus was characterized. The amplified orf10 (cpbJ) gene was subcloned into pET-28a(+) vector and expressed in E. coli BL21(DE3) strain by 0.5 mM IPTG at $30^{\circ}C$. The membrane fraction of recombinant E. coli cells was separated by ultracentrifugation, and solubilized using 2.5% octyl-$\beta$-D-glucoside. Using the solubilized membrane fraction, the artificial proteoliposomes were reconstituted and analyzed for the biological activity of CpbJ protein. Upon measuring ATPase activity, the proteoliposome made from recombinant E. coli membrane proteins showed slightly higher activity than that from host E. coli membrane proteins. In the measurement of membrane transport activity, the reconstituted proteoliposome of recombinant E. coli membrane proteins exhibited higher activity when both substrates of cephalosporin C and L-Ala-L-Ser were applied, compared to the case of cephalosporin C or L-Ala-L-Ser only. It implies that the CpbJ protein is an ABC transporter secreting cephabacin antibiotics synthesized in cytoplasm.

• 한국미생물·생명공학회지
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• 제10권3호
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• pp.171-175
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• 1982

항균 활성이 대체로 상승되었으나 Sarcina maginata의 경우는 약간 감소되었다. $\beta$-lactam 항생 물질인 penicillin G.Na와 ampicillin.Na도 인삼 saponin의 첨가로 항균 활성이 상승되었으나 Serratia 속 세균은 penicillin G.Na의 항균활성에 일정한 효과를 나타내지 않았다. 인삼 saponin 의 첨가에 의한 항생 물질들의 항균 활성의 변화는 Gram양성 세균 및 Gram음성 세균에 대해 일정하지 않은 상승 작용 혹은 길항작용과 같은 비특이성을 나타내었다. 세균의 약제 내성 현상도 인삼 saponin자 항생물질의 투여로 배제될 수 있을 것으로 사료되었다.