• Mycobiology
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• v.44 no.4
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• pp.338-342
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• 2016

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.160-167
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• 2014

Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the $P_1$ and $P_2$ positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

• Journal of Pharmaceutical Investigation
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• v.12 no.1
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• pp.1-11
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• 1982

Silver sulfadiazine has been introduced to replace silver nitrate in the topical treatment of extensive burns and this drug exerts a prominent antibacterial action against Pseudomonas aeruginosa. The compound is painless upon application and insufficient sulfadiazine is absorbed to cause crystalluria. The primary purpose of the study was to clarify the antimicrobial action of zinc sulfadiazine ointment in comparison with silver sulfadiazine ointment as well as the pharmaceutical properties of the zinc sulfadiazine preparations. The results are summerized as followings: 1) The optimum ratio of two substrate compounds for the synthesis of zinc sulfadiazine are 2 moles of sulfadiazine and 1 mole of zinc sulfate at pH 6.0. 2) The stability of zinc sulfadiazine ointment preparation by using polyethylene glycol base, Beeler's base or polyoxyl 40 stearate base was more stable than that of silver sulfadiazine preparations. 3) The antimicrobial action of zinc sulfadiazine exhibits a stronger antimicrobial activity than that of sulfadiazine against Staphylococcus aureus but the opposite is true against Pseudomonas aeruginosa.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.27-33
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• 1997

Recently ion beam assistant deposition (IBAD) was successfully used to produce a dense ultra-adherent and pinhole-free hydroxyapatite (HAp) layer on alumina substrate. After that the HAp-coated alumina was immersed in 20ppm and 100ppm $AgNO_3$ solution at room temperature for 48 hours to carry out the ions exchange between $Ag^+\;and\;Ca^+$ in HAp. The obvious antimicrobial effect against E.Coli, P. Aeruginosa and S. Epidermidis was observed in the samples treated with 20ppm $AgNO_3$ Solution, In contrast to this the untreated samples did not show any bactericidal effect. Scanning electron microscope(SEM) study showed that Ag homogeneously distributed on the surface. X-ray diffraction (XRD) demonstrated that the surface structure in the samples without Ag was HAp whereas with Ag is HAp and AgCaP. It appears that silver ions exchange with calcium ions in HAp does not cause significant changes in the structure of HAp coatings.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.964-968
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• 2001

It was carried out for research and development of natural antimicrobial on Scutellariae Radix extract against food-borne infection bacteria .Scutellariae Radix extract showed remarkable antimicrobial activites against Bacillus cereus, Listeria monocytogenes, Escherichia coli, and Vivro parahaemolyticus when examined by disk method, it was very stable on the wide rane of temperature and pH,.The growth rates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, and Vivro parahaemolyticus were decreased at the concentration of more than 500 ppm Scutellariae Radix extract, Indicating that the minimum inhibitory concentration (MIC)of the Bacillus cereus, Listeria monocytogenes, Escherichia coli, and Vivro parahaemolyticus to Scutellariae Radix extract were around 500 ppm . The morphological changes were observed by transmission electron microscope and scanning electron microscope and the microbial cells membran was destroyed by Scutellariae Radix extract. It was identified that the membrane integrity of the sensitive cells was disrupted by exposure to Scutellariae Radix extract as the $\beta$-galactosidase test on experimental substrate ONPG(o-nitrophenyl-$\beta$-D-galacto-pyranoside)

• Mycobiology
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• v.43 no.3
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• pp.311-318
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• 2015

Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding ${\beta}$-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.577-583
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• 2014

In this study, we evaluated fermentation characteristics of microorganism with antimicrobial activity in makgeolli made from various kinds of koji and nuruk during fermentation. The pH of nuruk groups decreased compared to the koji groups after 3 days of fermentation. Acidity and alcohol contents of nuruk groups significantly increased compared to the koji groups. The total sugar contents of the koji groups were significantly higher than those of the nuruk groups after 15 days of fermentation. Sensory scores of koji groups (DKB) were higher than those of other samples. Antimicrobial activities of nuruk group (GND and ANF) against Salmonella enterica, Bacillus subtilis, Escherichia coli, and Bacillus cereus were significantly higher compared to the koji group. ST-1, isolated from (Geumjeonggu nuruk D), showed the highest antimicrobial activity and was identified as Paenibacillus polymyxa strain RCP6 based on 16S rRNA sequencing. Our result suggest that Paenibacillus polymyxa from nuruk group produces a bacteriocin-like substrate with antimicrobial activity.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.456-462
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• 1994

Lysozyme-dextran hybrids were prepared by incubated storage at $60^{\circ}C$ and 80% relative humidity for 16 days. The emulsifying properties of the hybrids were about 14 times higher than those of native lysozyme and were about 3 times higher than those of commercial emulsifiers. Lytic activity of the hybrids remained about 83% that of native lysozyme when mesured against Micrococcus lysodeikticus as a substrate. The excellent emulsifying properties of the hybrids were maintained even at pH 3 and were further improved at pH 10. The emulsifying properties of the hybrids were greatly improved by preheating the hybrids at $100^{\circ}C$. In addition the lysozyme-dextran hybrids showed an antimicrobial effect on Gram-negative bacteria.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.15-20
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• 2023

Ionic liquids are considered as a promising, alternative solvent for the electrochemical synthesis of metals because of their high thermal and chemical stability, relatively high ionic conductivity, and wide electrochemical window. In particular, their wide electrochemical window enables the electrodeposition of metals without any side reaction of electrolytes such as hydrogen evolution. The electrodeposition of silver is conducted in 1-n-butyl-3-methylimidazolium chloride ([C4mim]Cl) ionic liquid system with a silver source of AgCl. This study is the first attempt to electrodeposit silver nanoparticles without using co-solvents other than [C4mim]Cl. Pulse electrolysis is employed for the synthesis of silver nanoparticles by varying applied potentials from -3.0 V to -4.5 V (vs. Pt-quasi reference electrode) and pulse duration from 0.1 s to 0.7 s. Accordingly, the silver nanoparticles whose size ranges from 15 nm to ~100 nm are obtained. The successful preparation of silver nanoparticles is demonstrated regardless of the kinds of substrate including aluminum, stainless steel, and carbon paper in the pulse electrolysis. Finally, the antimicrobial property of electrodeposited silver nanoparticles is confirmed by an antimicrobial test using Staphylococcus aureus.

• Journal of Life Science
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• v.12 no.6
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• pp.803-811
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• 2002

The present study was carried out for research and development of natural antimicrobial from extract of Stachys sieboldii MIQ against food borne bacteria. The hexane extract of Stachys sieboldii MIQ at 250$\mu\textrm{g}$/$m\ell$ per disc showed 15 ~ 20 mm inhibition zone against gram positive and gram negative barteria. Minimum inhibitory concentration (MIC) of hexane extract was 250${\mu}g$/$m\ell$against Bacillus cereus, 250~500${\mu}g$/$m\ell$against Listeria monocytogenes, 500${\mu}g$/$m\ell$ against Staphylococcus aureus, Psedomonas aeruginosa. Observation by transmission electron microscope, showed that disruption of the cell wall assumed to be due to the bactericidal activity. In addition, the membrane integrity of the sensitive cells was disrupted by exposure to Stachys sieboldii MIQ extract on the D-$\beta$-galatosidase activity as substrate of O-nitrophenol-$\beta$-D-galacto-pyranoside. The hexane extract of Stachys sieboldii MIQ was very stable on the pH and thermal stability.