• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1209-1216
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• 2018

This study aimed to evaluate the antimicrobial activity of 2-phenylethynyl-butyltellurium (PEBT) in Escherichia coli and the relation to its pro-oxidant effect. For this, we carried out the disk diffusion test, minimum inhibitory concentration (MIC) assay, and survival curve analysis. We also measured the level of extracellular reactive oxygen species (ROS), activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and level of non-protein thiols (NPSH). PEBT at 1.28 and 0.128 mg/disk exhibited antimicrobial capability in the disk diffusion test, with an MIC value of 1.92 mg/ml, whereas PEBT at 0.96, 1.92, and 3.84 mg/ml inhibited bacterial growth after a 9-h exposure. PEBT at 3.84, 1.92, and 0.96 mg/ml increased extracellular ROS production, decreased the intracellular NPSH level, and reduced the SOD and CAT activities. Glutathione or ascorbic acid in the medium protected the bacterial cells from the antimicrobial effect of PEBT. In conclusion, PEBT exhibited antimicrobial activity against E. coli, involving the generation of ROS, oxidation of NPSH, and reduction of the antioxidant defenses in the bacterial cells.

• Food Science of Animal Resources
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• v.37 no.4
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• pp.502-510
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• 2017

This study investigated bacterial growth-inhibitory effect of 69 therapeutic herbal plants extracts on 9 bacterial strains using a disc diffusion assay. Especially, the antimicrobial activity of Psoraleae semen, which showed different activity on pathogenic Gram-positive and Gram-negative bacteria, was evaluated by MIC (minimal inhibition concentration) and biofilm formation assay. The effect of Psoraleae semen extract on bacterial cell membranes was examined by measurement of protein leakage (optical density at 280 nm) and scanning electron microscope (SEM). No clear zone was formed on discs containing Gram-negative bacteria, but Gram-positive bacteria exhibited clear zones. The MICs of Psoraleae semen extract were $8{\mu}g/mL$ for Streptococcus mutans, and $16{\mu}g/mL$ for Enterococci and Staphylococcus aureus. In addition, biofilm formation was inhibited at concentration $8-16{\mu}g/mL$. Protein leakage values and SEM images revealed that cell membranes of Gram-positive bacteria were impaired following exposure to the extract. Further, the extract inhibited the growth of Listeria monocytogenes in sausages. These results indicate that Psoraleae semen extract could be utilized as a natural antimicrobial agent against Gram-positive bacteria.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.271-282
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• 2019

The purpose of this study is to identify the antimicrobial effects of SSH(三神丸) and synerggy effects of the existing antibiotics Oxacillin and Ciprofloxacin on MRSA and to identify the mechanisms. In this case, the procedure and method for verifying anti-bacterial activity and active concentration of MARA by measuring the minimum inhibitory concentration (MIC) of the trichin is used to verify the potency and active concentration of MARA, to confirm the potency of the disease by treating antibiotics and trichine ethanol extract in parallel, and to confirm the anti-bacterial effect over time, when the trichine is activated as an anti-bacterial activity to MARA, and a compound. In addition, we hope that this research will not only serve as meaningful data for the development of new drugs to control MARA immunity, but also serve as an opportunity to further accelerate the research and development of antibiotics to overcome resistant strains.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.25-32
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• 2021

Inflammatory reactions activated by lipopolysaccharide (LPS) of gram-negative bacteria can lead to severe septic shock. With the recent emergence of multidrug-resistant gram-negative bacteria and a lack of efficient ways to treat resulting infections, there is a need to develop novel anti-endotoxin agents. Antimicrobial peptides have been noticed as potential therapeutic molecules for bacterial infection and as candidates for new antibiotic drugs. We previously designed the 9-meric antimicrobial peptide Pro9-3 and it showed high antimicrobial activity against gram-negative bacteria. Here, to further examine its potency as an anti-endotoxin agent, we examined the anti-endotoxin activities of Pro9-3 and elucidated its mechanism of action. We performed a dye-leakage experiment and BODIPY-TR cadaverine and limulus amebocyte lysate assays for Pro9-3 as well as its lysine-substituted analogue and their enantiomers. The results confirmed that Pro9-3 targets the bacterial membrane and the arginine residues play key roles in its antimicrobial activity. Pro9-3 showed excellent LPS-neutralizing activity and LPS-binding properties, which were superior to those of other peptides. Saturation transfer difference-nuclear magnetic resonance experiments to explore the interaction between LPS and Pro9-3 revealed that Trp3 and Tlr7 in Pro9-3 are critical for attracting Pro9-3 to the LPS in the gram-negative bacterial membrane. Moreover, the anti-septic effect of Pro9-3 in vivo was investigated using an LPS-induced endotoxemia mouse model, demonstrating its dual activities: antibacterial activity against gram-negative bacteria and immunosuppressive effect preventing LPS-induced endotoxemia. Collectively, these results confirmed the therapeutic potential of Pro9-3 against infection of gram-negative bacteria.

• Korean Journal of Exercise Nutrition
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• v.25 no.4
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• pp.24-37
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• 2021

[Purpose] To determine whether physical activity (PA), primarily the recommended 60 minutes of moderate-to-vigorous PA, is associated with gut bacterial microbiota in 10-year-old children. [Methods] The Block Physical Activity Screener, which provides minutes/day PA variables, was used to determine whether the child met the PA recommendations. 16S rRNA sequencing was performed on stool samples from the children to profile the composition of their gut bacterial microbiota. Differences in alpha diversity metrics (richness, Pielou's evenness, and Faith's phylogenetic diversity) by PA were determined using linear regression, whereas beta diversity (unweighted and weighted UniFrac) relationships were assessed using PERMANOVA. Taxon relative abundance differentials were determined using DESeq2. [Results] The analytic sample included 321 children with both PA and 16S rRNA sequencing data (mean age [SD] =10.2 [0.8] years; 54.2% male; 62.9% African American), where 189 (58.9%) met the PA recommendations. After adjusting for covariates, meeting the PA recommendations as well as minutes/day PA variables were not significantly associated with gut richness, evenness, or diversity (p ≥ 0.19). However, meeting the PA recommendations (weighted UniFrac R² = 0.014, p = 0.001) was significantly associated with distinct gut bacterial composition. These compositional differences were partly characterized by increased abundance of Megamonas and Anaerovorax as well as specific Christensenellaceae_R-7_group taxa in children with higher PA. [Conclusion] Children who met the recommendations of PA had altered gut microbiota compositions. Whether this translates to a reduced risk of obesity or associated metabolic diseases is still unclear.

• The Journal of Korean Medicine
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• v.42 no.4
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• pp.25-39
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• 2021

Objectives: Ssanghwa-tang (SHT) is a traditional herbal formula comprising nine medicinal herbs, and it is used for reducing fatigue in Korea. SHT exerts various effects such as anti-inflammatory, antioxidant, and anti-aging activities, and protection against acute hepatotoxicity. However, the genotoxicity of SHT has not yet been established. Methods: Ten components were identified in SHT water extract by using high-performance liquid chromatography analysis. We assessed the genotoxicity of SHT by using bacterial reverse mutation (Ames test), chromosome aberration, and in vivo micronucleus tests. Results: The contents of paeoniflorin, glycyrrhizin, and liquiritin apioside in SHT were 15.57, 6.94, and 3.48 mg/g extract, respectively. SHT did not increase the revertant colonies of Salmonella typhimurium and Escherichia coli strains in the presence or absence of metabolic activity. Although SHT did not induce structurally abnormal chromosomes in Chinese hamster lung (CHL) cells in the presence of metabolic activity, the number of structurally aberrated chromosomes increased dose-dependently in the absence of metabolic activity. In the in vivo micronucleus test, SHT did not affect the formation of micronuclei compared with the vehicle control. Conclusions: Genotoxicity of SHT was not observed in the Ames test and in vivo micronucleus test. However, based on the results of chromosome aberration test, it can be presumed that SHT has the potential to induce genotoxicity because it induced structurally abnormal chromosomes in the absence of metabolic activity.

• Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.28.1-28.7
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• 2016

Background: Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm) on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results: We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and $68.4J\;cm^{-2}$, respectively, produced one log reduction in the bacterial populations), whereas Streptococcus parauberis was the least susceptible ($153.8J\;cm^{-2}$ per one log reduction). In general, optical density (OD) values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions: This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1613-1620
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• 2012

Bacterial wilt caused by Ralstonia solanacearum is a devastating disease of many economically important crops. Since there is no promising control strategy for bacterial wilt, phage therapy could be adopted using virulent phages. We used phage PE204 as a model lytic bacteriophage to investigate its biocontrol potential for bacterial wilt on tomato plants. The phage PE204 has a short-tailed icosahedral structure and double-stranded DNA genome similar to that of the members of Podoviridae. PE204 is stable under a wide range of temperature and pH, and is also stable in the presence of the surfactant Silwet L-77. An artificial soil microcosm (ASM) to study phage stability in soil was adopted to investigate phage viability under a controlled system. Whereas phage showed less stability under elevated temperature in the ASM, the presence of host bacteria helped to maintain a stable phage population. Simultaneous treatment of phage PE204 at $10^8$ PFU/ml with R. solanacearum on tomato rhizosphere completely inhibited bacterial wilt occurrence, and amendment of Silwet L-77 at 0.1% to the phage suspension did not impair the disease control activity of PE204. The biocontrol activities of phage PE204 application onto tomato rhizosphere before or after R. solanacearum inoculation were also investigated. Whereas pretreatment with the phage was not effective in the control of bacterial wilt, post-treatment of PE204 delayed bacterial wilt development. Our results suggested that appropriate application of lytic phages to the plant root system with a surfactant such as Silwet L-77 could be used to control the bacterial wilt of crops.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.584-589
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• 1995

To select new useful plants with antibacterial activity, ninety five sample of eighty different species of wild plants were collected, and extracted with methanol. Antibacterial activity of the methanol extracts was tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Vibrio parahaemolyticus. The methanol extracts from Artemisia capillaris, Hemistepta lyrata, Youngia japonica, Prunella vulgaris, Lamium amplexicaule and Juniperus chinensis was effective against all bacterial strains tested, and eight methanol extracts including Ixeris dentata, Gnaphalium affine, Chelidonium majus and Spiraea prunifolia exhibited the antibacterial activity against at least 3 bacterial strains. Methanol extracts from leaf of Syringa vulgaris, Drava nemorosa and clove of Erythronium japonicum showed a selective antibacterial activity against two gram negative bacteria, V. parahaemolyticus, and B. subtilis, respectively. With investigations on antibacterial activity against a certain bacterial strains tested, metahnol extracts from clove of Erythronium japonicum, Spiraea prunifolia, leaf and twig of Camelia japonica, and Drava nemorosa showed strongest activities against B. subtilis, S. aureus, E. coli, and V. parahaemolyticus, respectively. Nine methanol extracts based on the results were successively fractionated with n-hexane, chloroform, ethyl acetate and water portions, which were examined antibacterial activity against B. subtilis and V. parahaemolyticus. Among the all fractions tested, chloroform fractions of Hemistepta lyrata showed strongest antibacterial activity against both B. subtilis (17mm) and V. parahaemolyticus (29 mm). Chloroform fractions of Youngia japonica, n-hexane fractions of Artemisia capillaris, Iexeris dentata and Prunella vulgaris, and ethyl acetate fraction of leaf and twig of Camelia japonica showed relatively a strong antibacterial activity. On the other hand, Juniperus chinensis and Equisetum arvense was distributed to all fractions except for water fraction.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.164-170
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• 2008

Carbon utilization by Chryseobacterium strain KJ1R5 was studied to enhance its biocontrol activity against Phytophthora capsid. Chryseobacterium strain KJ1R5 has previously been shown to control Phytophthora blight of pepper (Capsicum annuum L.). Strain KJ1R5 could utilize carbon sources such as L-arabinose, D-cellobiose, ${\beta}-lactose$ and D-galactose well. P. capsici could utilize D-glucose well, showing the absorbencies ranged from 0.577 to 0.767 at 600nm. When 2% L-arabinose, which could only be utilized by the bio-control strain KJ1R5, was amended into the bacterial suspension, the efficacy of biological control increased. Among the amendments of various carbon sources into bacterial suspension, L-arabinose and D-(+)-glucose significantly enhanced biological control activity, resulting in a reduction of disease incidence to 6.9%, compared to 21.9% for the strain KJ1R5 alone and 81.3% for P. capsici inoculation alone, indicating that amendment with specific carbon sources could increase the biological control activity.