• Korean Journal of Microbiology
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• v.52 no.3
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• pp.327-335
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• 2016

A novel Amycolatopsis strain KCTC 29142 was isolated and characterized based on the polyphasic taxonomic analysis including morphological observation, phylogenetic analysis, physiological and chemotaxonomic characteristics. The ethyl acetate extract of strain KCTC 29142 culture broth showed strong antibacterial activity and the active compound was identified as siderochelin A, a ferrous-ion chelating compound. In this study, siderochelin A showed good activity against multi-drug resistant pathogens, including Acinetobacter baumanii, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and Escherichia coli (E. coli). The minimum inhibitory activity against clinical isolates was also determined.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.73-79
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• 2013

The fruit of the black raspberry (Rubus coreanus Miquel) has been employed in traditional medicine, and recent studies have demonstrated its measureable biological activities. However, the root of the black raspberry has not been studied. Therefore, in this study, we evaluated the anti-inflammatory and antibacterial properties of the root and unripe fruit polyphenols of the black raspberry. Both polyphenols proved to have anti-inflammatory activity as evidenced by the decreased nitric oxide (NO), cytokines (IL-$1{\beta}$, IL-6, and IL-10) and prostaglandin E2 ($PGE_2$) levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. However, root polyphenols showed stronger anti-inflammatory activity than fruit polyphenols. LPS-induced mRNA and protein expressions of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 levels were also decreased, confirming the anti-inflammatory activity. Root polyphenols showed lethal activity against methicillin-resistant Staphy-lococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRAB), and Bacillus anthracis. In contrast, the black raspberry fruit did not demonstrate these properties. These data provide the first demonstration that black raspberry root has potential anti-inflammatory and anti-superbacterial properties that can be exploited as alternatives for use in the food and cosmetic industries and/or as pharmaceuticals.

• Tuberculosis and Respiratory Diseases
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• v.72 no.1
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• pp.30-36
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• 2012

Background: Patients with ventilator-associated pneumonia (VAP) in intensive care unit (ICU) have a high mortality rate. The routine surveillance cultures obtained previously or an ATS guideline for hospital-acquired pneumonia was used in selecting initial antimicrobials. The object of this study was to compare the respiratory samples before VAP and bronchoalveolar lavage (BAL) culture. Methods: 54 patients underwent fiberoptic bronchoscopy to obtain BAL samples. We reviewed microbiologic specimen results of prior respiratory specimens (pre-VAP) and BAL. Results: Among 51 patients with 54 VAP episodes, 52 microorganisms of pre-VAP and 56 BAL samples were isolated. Pre-VAP included 21.2% of MRSA, and 32.6% of multidrug resistant-Acinetobacter baumannii (MDR-AB). BAL samples comprised 25.0% of MRSA, 26.7% of MDR-AB, 14.3% of Stenotrophomonas maltophilia and 3.6% of Klebsiella pneumonia in order. In pre-VAP samples compared to BAL samples, only 35.2% were identical. In BAL samples compared to pre-VAP samples obtained in 5 days before the onset of VAP, only 43.6% were identical. However, among BAL samples compared to pre-VAP samples obtained after more than 5 days, 13.3% were identical (p=0.037). Conclusion: Based on these data, pre-VAP samples obtained prior to 5 day onset of VAP may help to predict the causative microorganisms and to select appropriate initial antimicrobials.

• KSBB Journal
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• v.26 no.2
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• pp.100-106
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• 2011

Strain BCNU 5011 was isolated from forest soil samples collected in the Taebaek mountain in the Gangwon province, Korea. The biochemical, physiological and 16S rRNA sequence analysis strongly indicated that this isolate was most closely related to Paenibacillus polymyxa. A maximum production level of antimicrobial substances of Paenibacillus sp. BCNU 5011 was achieved under aerobic incubation at $30^{\circ}C$ for 3 days in SST broth.Paenibacillus sp. BCNU 5011 showed a broad spectrum of activity against Gram positive and Gram negative bacteria, including methicllinresistant Staphylococcus aureus (MRSA). Paenibacillus sp. BCNU 5011 was also shown to inhibit the growth of different potential human pathogenic bacteria and fungi in vitro. Peptide extract showed better antimicrobial activity than solvent extracts. But active antimicrobial compounds might be included in both peptide extract and solvent extracts. Further separation, purification and identification of active principles leads project to develop antimicrobial agents and anti-MRSA agents.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1249-1250
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• 2015

We report a plasma-on-a-chip (POC) which provides a non-thermal atmospheric plasma for superbacteria infection treatment A three-electrode configuration allows an initiation carrier injection prior to a primary discharge, leading to a significant reduction in a breakdown voltage. A stable non-thermal argon plasma is generated using a pulsed glow discharge and inactivation of anti-biotic resistant bacteria, for example MRSA, is successfully demonstrated by exposing the bacteria to the argon plasma in a couple of minutes.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.800-805
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• 2012

Licochalcone E was firstly isolated from licorice root in 2005, which belongs to the retrochalcone family. Studies on the biological activities of licochalcone E were in the initial stage. In the study, we demonstrated that licochalcone E has potent antimicrobial property against Staphylococcus aureus. Furthermore, via hemolysis, Western blot, and real-time RT-PCR assays, we have shown that subinhibitory concentrations of licochalcone E dose-dependently reduces the production of ${\alpha}$-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The data suggest that licochalcone E may deserve further investigation as a potential therapeutic against S. aureus infections, or the structure of licochalcone E may be used as a basis for chemical synthesis of novel anti-S. aureus compounds.

• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.469-481
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• 2014

IIn vitro antimicrobial and anti-inflammatory activities of nargenicin and its derivatives were investigated. Nargenicin, an unusual macrolide antibiotic with potent anti-MRSA (methicilin-resistant Staphylococcus aureus) activity, was purified from the culture broth of Nocardia sp. CS682. And variety of novel nargenicin derivatives was synthesized from nargenicin. Two compounds (4 and 5) exhibit a broad spectrum of antimicrobial activities against infectious bacteria. The antimicrobial activity of derivatives against fifteen organisms was assessed using the minimum inhibitory concentration (MIC). The MIC values were in the ranges of $0.15{\sim}80{\mu}g/mL$ (w/v) for compound 1 and 2, $5{\sim}80{\mu}g/mL$ (w/v) for compound 3, $1.25{\sim}40{\mu}g/mL$ (w/v) for compound 4, and $1.25{\sim}80{\mu}g/mL$ (w/v) for compound 5, depending on the pathogens studied. In vitro, we investigated cytotoxicity and inhibition of nitric oxide (NO) production of synthesized compounds 1-5 in Raw 264.7 cells. LPS-induced nitric oxide releases were significantly blocked by compound 3, 4 and 5 in a dose-dependent manner. At high concentrations ($5{\mu}g/mL$) compound 5 inhibited the NO production by 95%. Compound 4 inhibited the release of NO in LPS-activated Raw 264.7 cells by 75% at the concentration of $10{\mu}g/mL$. Compound 3 inhibited the release of NO in LPS-activated Raw 264.7 cells by 65% at the concentration of $100{\mu}g/mL$. On the other hand, nargenicin, compound 1 and 2 did not inhibit NO production. These results demonstrated that compound 4 and 5 displayed antimicrobial activity and blocked LPS-induced pro-inflammatory mediators such as NO in macrophages, which might be responsible for its therapeutic application.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1278-1283
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• 2007

The 30% resistant frequencies of pathogenic bacteria were identified against generally utilizing disinfectants. Among the used disinfectants, foodsef, Taego, and Iodo 175 were dictated by lower sensitivities against pathogenic bacteria, as well as higher resistant frequencies when compared with other disinfectants. The resistant frequencies against antibiotics were also dictated by 30% through MIC (minimal inhibitory concentration) and paper disc methods. Especially, the used bacteria exhibited resistances against gentamycin, kanamycin, and streptomycin, which included in all aminoglycoside group. The MBT-01108 material, which extracted and purified from a powder obtained by processing of Opunita ficus-indica var. saboten Makino trunk, did not develop or grow resistant bacteria. Interestingly, the multi-drug resistant bacteria such as MRSA, resistant Pseudomonas aeruginosa, VRE, and E. coli 0157 did not resistant against MBT-01108 material. These results suggest that MBT-01108 material uses as an anti-microbial agent.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.279-286
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• 2005

The Opuntia ficus-indica var. saboten Makino (Cactus) is a tropical or subtropical plant, which is cultivated or grows naturally in Jeju island. It has been widely used as folk medicine for burned wound, edema and indigestion. In addition, its extract has been claimed to have several biological activities including anti-inflammation in oriental medicine. In this study, we examined the antimicrobial activities of the methanol extract of Opuntia ficus-indica var. saboten Makino. The extract showed a broad spectrum of antimicrobial activity against pathogenic bacteria, including antibiotics resistant bacteria (MRSA, R-P. aeruginosa, VRE) and Propionibacterium acnes, yeast, and fungi. The extract retained the activity after heat treatment for 15 min at $100^{\circ}C$ and $121^{\circ}C$ and after extended storage, up to 10 weeks storage period at $4^{\circ}C$ and $25^{\circ}C$, also stably retained its activity. It showed a better inhibitoring effect to the growth of E. coli than sodium benzoate did it at the same concentration. Addition of various salts or metal ions did not affect on its antimicrobial activity. Therefore, the antimicrobial characteristics of the extract can be applicable as a natural preservative and an antimicrobial agent for bacterial disease.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.115-122
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• 2021

Phenol-soluble modulins (PSMs) are responsible for regulating biofilm formation, persister cell formation, pmtR expression, host cell lysis, and anti-bacterial effects. To determine the effect of psm deletion on methicillin-resistant Staphylococcus aureus, we investigated psm deletion mutants including Δpsmα, Δpsmβ, and Δpsmαβ. These mutants exhibited increased β-lactam antibiotic resistance to ampicillin and oxacillin that was shown to be caused by increased N-acetylmannosamine kinase (nanK) mRNA expression, which regulates persister cell formation, leading to changes in the pattern of phospholipid fatty acids resulting in increased anteiso-C15:0, and increased membrane hydrophobicity with the deletion of PSMs. When synthetic PSMs were applied to Δpsmα and Δpsmβ mutants, treatment of Δpsmα with PSMα1-4 and Δpsmβ with PSMβ1-2 restored the sensitivity to oxacillin and slightly reduced the biofilm formation. Addition of a single fragment showed that α1, α2, α3, and β2 had an inhibiting effect on biofilms in Δpsmα; however, β1 showed an enhancing effect on biofilms in Δpsmβ. This study demonstrates a possible reason for the increased antibiotic resistance in psm mutants and the effect of PSMs on biofilm formation.