• 한국미생물·생명공학회지
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• 제38권4호
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• pp.481-485
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• 2010

Lactobacillus plantarum strain KK3 with tannase activity was isolated from Gochunipkimchi (red pepper leaf kimchi) and showed a high antagonistic activity against five kinds of food pathogens. Strain KK3 secreted antibacterial compound into culture medium and 24-h culture in MRS broth at $30^{\circ}C$ was enough for the antibacterial compound production. The crude antibacterial compound prepared from culture supernatant inhibited the growth of some Gram-negative bacteria and Bacillus cereus but not Listeria monocytogenes. The antibacterial activity was sensitive to proteinase K treatment, confirming its proteinaceous nature (bacteriocin). The crude bacteriocin was active in the pH range 3.5-8.5 and extremely stable after 15 min of heat treatment at $121^{\circ}C$. The strain KK3 produced equally active bacteriocin in Chinese cabbage juice as it produced in MRS broth.

• 한국미생물·생명공학회지
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• 제27권4호
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• pp.339-343
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• 1999

Pasteurella haemolytica is well known to cause severe pneumonia, consolidation and oedema of the lung, and fibrinous pleurisy under the stress and infection of virus in the cattle. In the course of our screening for antimicrobial agents against P.haemloytica, compound 51086 has been isolated from the fermentation broth of Streptimyces sp. 51086. The compound 51086 was purified by SiO2, Sephadex LH-20 and ODS column chromatographies and HPLC, subsequently. The structure of compound 51086 was determined as hygromycin A by combination of 1H NMR, 13C NMR, HMBC, and ESI-MS. This compound showed significant antibacterial activity against P.haemolytica and P.multocida.

• 한국연초학회지
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• 제17권2호
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• pp.103-108
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• 1995

Antibiotic and physico-chemical properties of an active compound from actinomycetes isolate G-37, of which the culture filtrate had an inhibitory effect against tobacco mosaic virus(W) infection, were examined. The active compound, which was purified by ethylacetate extraction, silica gel column chromatography, preparative thin layer chromatography, and high performance liquid chromatography, showed strong antibacterial activities especially against Gram-positive bacteria including Bacillus subtillis, Sarcina lutea and Staphylococcus aureus. From the IH-NMR, FAB/RfS, UV spectral data, and physicochemical properties, the active compound of G-37 appears to belong to a peptide antibiotic group. Among the known peptide antibiotics in the antibiotic group, No. 280, A-30912, and Taitomycin showed molecular weights and ultra violet spectrum similar to those of the active compound from G-37, but was not identical to the compound, which suggests that it may be a new peptide antibiotics.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.129-129
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• 1998

The Pasteurella haemolytica-induced pneumonic lesions are frequently occurred with stress and infection of virus in the cattle. In the course of screening for antimicrobial activity against Pasteurella haemolytica, compound 51086 has been isolated from the fermentation broth of the strain streptomyces sp. The compound 51086 was purified by column chromatography and HPLC, subsequently. The structure of compound 51086 was determined as a hygromycin A by a combination of $^1$H NMR, $\^$l3/C NMR, HMBC, and ESI -MS. This compound showed significant antibacterial activity against P. haemolytica and P. multocidn in Gram-negative bacteria.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.225-236
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• 2013

Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at $30^{\circ}C$. Interestingly, antibacterial activity remained unchanged after heating at $121^{\circ}C$ for 45 min, 24 h storage in temperature range of $70^{\circ}C$ to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.

• 한국미생물·생명공학회지
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• 제38권1호
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• pp.84-92
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• 2010

B. subtilis MJP1이 생산하는 항균물질을 분리 정제하기 위하여 SPE, IEC, GFC를 통한 정제를 수행하였다. 정제된 항세균 물질은 tricine SDS-PAGE에서 하나의 band임을 확인 한 후 N-말단 아미노산 서열분석을 하였으나 N-말단이 blocking 되어 그 서열을 분석할 수 없였다. 이에 그 내부서열을 알아보기 위한 LC를 이용한 ESI-MS/MS를 시행하였으나 내부서열도 확인할 수 없었고, UPLC를 이용한 ESI-MS/MS를 시행한 결과 항세균 활성 물질은 분자량이 매우 유사한 2개의 peptide(3356.54 Da, 3400.5244 Da)가 존재함을 확인하였다. 정제된 항세균 물질의 항균 spectrum을 조사한 결과, L. monocytogenes에 가장 강한 항균활성을 나타내며 이외에 B. subtilis, S. aureus subsp. aureus, E. faecalis 등의 Gram 양성균에서 항균활성을 나타내였다. 정제된 B. subtilis 항세균 물질은 pH 3.0부터 pH 9.0 범위에서는 안정하였으며 $4^{\circ}C$, $30^{\circ}C$, $50^{\circ}C$에서 24시간, $100^{\circ}C$에서 5분 동안 매우 안정하였고, $70^{\circ}C$에서 24 시간, $100^{\circ}C$에서 30분 동안 처리한 구간부터 역가가 감소하여 $121^{\circ}C$에서 15분 동안 처리한 구간에서는 역가가 완전히 소실되었다. 효소 안정성 실험에서 정제된 항세균 물질은 일부 단백분해효소에 의해 분해되어 역가를 상실하였으며, lipase나 $\alpha$-amylase에서는 안정함을 나타냈다. 이로부터 정제된 항세균 물질이 넓은 pH 범위에서 안정하고, 비교적 높은 온도에서도 활성을 유지한다는 점을 관찰할 수 있었으며, 단백분해효소에 의해 분해되므로 bacteriocin임을 확인하였다. 본 연구를 통하여 B. subtilis MJP1으로부터 분리 정제된 bacteriocin은 class IIa군의 특성과 유사하며, B. subtilis MJP1은 본 분리 bacteriocin 이외에도 다른 항세균 물질과 항진균 물질을 생산하는 균주임을 알 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제10권4호
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• pp.8-22
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• 1980

In order obtain some new antibacterial agents, seven new 2-ethoxymethyl-3-(5-nitro-2-furyl) acrylamide derivatives were synthesized by condensing 2-ethoxymethyl-3-(5-nitro-2-furyl) acyloyl chloride with amino compounds namely 5-amino-3, 4-dimethyl isoxazole, sulfamonomethoxazole, d-2-amino-1-butanol, hydroxylamine hydrochloride, semicarbazide hydrochloride, thiosemicarbazide, and p, p'-diaminodiphenylsulfone, respectively. The seven synthesized compounds were 2-ethoxymethyl-3-(5-nitro-2-furyl) acryl-5-amino-3, 4-dimethylisoxazoleamide [VII], $N^4-[2-ethoxymethyl\;3-methyl\;(5-nitro-2-furyl)\;acryl]-N^1-(5-methyl-3-isoxazolyl)$ sulfanilamide [VIII], 2-ethoxyl-3-(5-nitro-2-furyl) acrylsemicarbazide [X], 2-ethoxymethyl-3-(5-nitro-2-furyl) acrylthiosemicarbazide [XI], 2-ethoxymethyl-3-(5-nitro-2-furyl) acryl-d-2-amino-1-butanolamide [XII], and 4, 4'-di[2-ethoxymethyl-3-(5-nitro-2-furyl) acryl-amido] diphenylsulfone [XIII]. These compounds, with exception of the compound XIII, showed generally effective antibacterial activity, especially in the following instances. Compound VII was shown to be effective against Bacillus subtilis ATCC 6633 compound VIII, against Bacillus cereus var. Mycoides ATCC 1778, and compound XII, against both Proteus vuglaris and Saccharomyces cerevisiae ATCC 9763.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1441-1448
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• 2017

Antibacterial compounds are widely used in the treatment of human and animal diseases. The overuse of antibiotics has led to a rapid rise in the prevalence of drug-resistant bacteria, making the development of new antibacterial compounds essential. This study focused on developing a fast and easy method for identifying marine bacteria that produce antibiotic compounds. Eight randomly selected marine target bacterial species (Agrococcus terreus, Bacillus algicola, Mesoflavibacter zeaxanthinifaciens, Pseudoalteromonas flavipulchra, P. peptidolytica, P. piscicida, P. rubra, and Zunongwangia atlantica) were tested for production of antibacterial compounds against four strains of test bacteria (B. cereus, B. subtilis, Halomonas smyrnensis, and Vibrio alginolyticus). Colony picking was used as the primary screening method. Clear zones were observed around colonies of P. flavipulchra, P. peptidolytica, P. piscicida, and P. rubra tested against B. cereus, B. subtilis, and H. smyrnensis. The efficiency of colony scraping and broth culture methods for antimicrobial compound extraction was also compared using a disk diffusion assay. P. peptidolytica, P. piscicida, and P. rubra showed antagonistic activity against H. smyrnensis, B. cereus, and B. subtilis, respectively, only in the colony scraping method. Our results show that colony picking and colony scraping are effective, quick, and easy methods of screening for antibacterial compound-producing bacteria.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.215-218
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• 2002

A methanol extract of Physalis angulata exhibited in vitro antibarterial activity against oral pathogens such including Streptococcus mutans and Porphyromonas gingivalis. The methanol extract of Physalis angulata was further fractionated with ethyl acetate, n-butanol and water, in which the ethyl acetate fraction exclusively showed antibacterial activity. An active antibacterial compound from the ethyl acetate fraction was purified to a single compound using silica gel column chromatography and identified as oleanolic acid by $^{13}$ C-NMR, $^1$H-NMR and EI-MS. MIC of oleanolic acid against S. mutants and p. gingivalis were determined to be 50 and 25 ug/mL, respectively. The Antibacterial activity of oleanolic acid from Physalis angulata suggested that it has potential as an anticarcinogenic and antiperiodontic ingredients in various foods and oral care products.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.872-881
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• 2012

The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 $log_{10}$, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GC-MS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.