• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.103-103
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• 2019

Glycyrrhizae radix, commonly known as licorice, is a perennial herb belonging to Leguminosae and also includes various components such as, glycyrrhizin, liquiritin, liquiritigenin and isoliquiritigenin etc. Licorice has been widely used in East Asia as a medicine having pharmacological effects like antioxidants, anti-bacterial, anti-inflammatory, anti-cancer and immune modulatory activities. Among various licorice, Glycyrrhiza (G.) uralensis G. glabra and G. inflata are used for pharmaceutical purposes in Korea. However, cultivation of licorice has some problems such as low quality, low productivity, and early leaf drop. Korea Rural Development Administration developed new cultivars Wongam and Sinwongam, which are improved in cultivation and quality. To register the newly developed cultivar (s) on Ministry of Food and Drug Safety in Korea as a medicine, it is necessary to prove the similarity and difference through the comparative studies between already-registered species and new cultivars. Some fungi and bacteria usually in the human oral cavity and intestines exist as harmless state in human body. Also, the skin and genital infections by fungi can lead to toxic systemic infections and are accompanied by flushing, rashes, burning or painful sensation. The influences of licorice varieties on fungi and bacteria might be an evidence to prove the outstanding effect of newly developed licorice variety. In this study, the antifungal and antibacterial activity was investigated using newly developed licorice varieties Wongam, and Sinwongam against various fungi and bacteria. These results means newly developed licorice could be used as a replacement of already-registered species in terms of antifungal and antibacterial application.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.538-546
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• 2017

The occurrence of various pathogenic microorganisms on farms is a concern if they are able to contaminate fresh produce, which provides entry into the food supply. This study was undertaken to assess the microbiological quality and prevalence of pathogens in Chinese cabbage cultivated soil in Korea. A total of 57 Chinese cabbage cultivated soils were collected in 4 locations in Korea from February to August 2017. The soils were analyzed for the presence of total aerobic bacteria, Escherichia coli, coliforms, Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. The total aerobic plate counts in soils were in the range of 5.7 to $8.7log\;CFU\;g^{-1}$. The coliforms and E. coli were detected in 39 and 8 out of 57 soil samples, respectively, in the range of 1.1 to $6.3log\;CFU\;g^{-1}$ and 0.7 to $4.0log\;CFU\;g^{-1}$. Salmonella spp., E. coli O157:H7, L. monocytogenes, and S. aureus were not detected from any samples. Results from these studies may help control the spread of bacterial species such as E. coli and Salmonella spp. through the farm environment.

• Journal of Marine Life Science
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• v.6 no.1
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• pp.1-8
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• 2021

In marine ecosystems, the biosynthesis and catabolism of dimethylsulfoniopropionate (DMSP) by marine bacteria is critical to microbial survival and the ocean food chain. Furthermore, these processes also influence sulfur recycling and climate change. Recent studies using emerging genome sequencing data and extensive bioinformatics analysis have enabled us to identify new DMSP-related genes. Currently, seven bacterial DMSP lyases (DddD, DddP, DddY, DddK, DddL, DddQ and DddW), two acrylate degrading enzymes (DddA and DddC), and four demethylases (DmdA, DmdB, DmdC, and DmdD) have been identified and characterized in diverse marine bacteria. In this review, we focus on the biochemical properties of DMSP cleavage enzymes with special attention to DddD, DddA, and DddC pathways. These three enzymes function in the production of acetyl coenzyme A (CoA) and CO₂ from DMSP. DddD is a DMSP lyase that converts DMSP to 3-hydroxypropionate with the release of dimethylsulfide. 3-Hydroxypropionate is then converted to malonate semialdehyde by DddA, an alcohol dehydrogenase. Then, DddC transforms malonate semialdehyde to acetyl-CoA and CO₂ gas. DddC is a putative methylmalonate semialdehyde dehydrogenase that requires nicotinamide adenine dinucleotide and CoA cofactors. Here we review recent insights into the structural characteristics of these enzymes and the molecular events of DMSP degradation.

• Textile Coloration and Finishing
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• v.31 no.1
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• pp.1-13
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• 2019

In this study, eco-friendly functional leather was developed by recycling wastes such as eel skin, marigold(Tagetas erecta l.), hinoki cypress(Chamaecyparis obtusa). The hot water extracts of marigold and hinoki cypress leaves were freeze-dried at $-80^{\circ}C$ to prepare colorant powder. The dyeing of eel leather with marigold was carried out to investigate the effects of dyeing conditions, mordanting on dye uptake, color, morphological change, and color fastness. Considering shrinkage of eel leather caused by dyeing, the optimum dyeing conditions were $60^{\circ}C$ of dyeing temperature and 60 min of dyeing time at 1:100 of bath ratio, and color of the dyed eel leather was Y to YR Munsell series. In order to prevent the degradation of leather from microbe, we conducted combination dyeing with marigold and hinoki cypress leave colorants. In this case, the combination dyed eel leathers showed excellent antimicrobial activity with above 99% bacterial reduction rate against S. aurieus and K. pneumoniae. It was confirmed that all of the dyed eel leathers were sufficient to meet the Korean Standard for color fastness of leather products. It can be applied practically for the development of eco-friendly functional leather by utilizing some useful active components extracted from plant resources and by recycling food wastes.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.375-385
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• 2020

The purpose of this study was to investigate the quality characteristics of kimchi prepared with a single starter culture of biogenic amines (BA)-forming lactic acid bacteria (LAB) or a combined starter cultures composed of BA-forming and BA-degrading LAB. As the fermentation proceeded, the lactic acid bacterial count, titratable acidity, and BA content in kimchi prepared with myeolchi-aekjeot were slightly higher than those of kimchi prepared with saeu-jeot. The amount and type of BA produced by LAB were mostly strain dependent rather than species specific. Among all of the isolated LAB strains, the highest levels of cadaverine, histamine, putrescine and tyramine were produced by Leuconostoc mesenteroides MBK32, Lactobacillus brevis MBK34, Lactobacillus curvatus MBK31 and Enterococcus faecalis SBK31, respectively. BA-forming and BA-degrading starter cultures played an important role in the growth rate and organic acid-producing ability of LAB in kimchi. Interestingly, BA contents in kimchi increased by adding single BA-forming LAB starter were effectively lowered by the mixed cultures with BA-degrading LAB.

• 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.

• Journal of dental hygiene science
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• v.20 no.4
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• pp.213-220
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• 2020

Background: The leaves of Perilla frutescens, commonly called perilla and used for food in Korea, contain components with a variety of biological effects and potential therapeutic applications. The purpose of this study was to identify the components of 70% ethanol extracted Perilla frutescens (EEPF) and determine its inhibitory effects on oral microbial activity and production of nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharides (LPS)-stimulated Raw264.7 macrophages, consequently, to confirm the possibility of using EEPF as a functional component for improving the oral environment and preventing inflammation. Methods: One kg of P. frutescens leaves was extracted with 70% ethanol and dried at -70℃. EEPF was analyzed using high-performance liquid chromatography analysis, and antimicrobial activity against oral microorganisms was revealed using the disk diffusion test. Cell viability was elucidated using a methylthiazolydiphenyl-tetrazolium bromide assay, and the effect of EEPF on LPS-induced morphological variation was confirmed through microscopic observation. The effect of EEPF on LPS-induced production of pro-inflammatory mediators, NO and PGE2 was confirmed by the NO assay and PGE2 enzyme-linked immunosorbent assay. Results: The main component of EEPF was rosemarinic acid, and EEPF showed weak anti-bacterial and anti-fungal effects against microorganisms living in the oral cavity. EEPF did not show toxicity to Raw264.7 macrophages and had inhibitory effects on the morphological variations and production of pro-inflammatory mediators, NO and PGE2 in LPS-stimulated Raw264.7 macrophages. Conclusion: EEPF can be used as a functional material for improving the oral environment through the control of oral microorganisms and for modulating inflammation by inhibiting the production of inflammatory mediators.

• Journal of Dairy Science and Biotechnology
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• v.39 no.1
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• pp.9-19
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• 2021

Enterobacter sakazakii (Cronobacter spp.) causes meningitis, necrotizing enterocolitis, sepsis, and bacteremia in neonates and children and has a high mortality rate. For rapid E. sakazakii detection, various differential and selective media containing α-glucosidase substrates, such as 5-bromo-4-chloro-3-indolyl-α-D-glucopyranoside (BCIG) or 4-methylumbelliferyl-α-D-glucoside (α-MUG), have been developed as only E. sakazakii exhibits α-glucosidase activity in the genus Enterobacter. However, Escherichia vulneris (family: Enterobacteriaceae) can also utilize α-glucosidase substrates, thereby resulting in false positives. Various iron sources are known to promote the growth of gram-negative bacteria. This study aimed to develop a selective medium containing α-glucosidase substrates for E. sakazakii detection that would eliminate false positives, such as those of E. vulneris, and to determine the role of iron source in the medium. Three previously developed (TPD) media, i.e., Oxoid, OK, and VRBG, and the medium developed in this study, i.e., NGTE, were evaluated using 58 E. sakazakii and 5 non-E. sakazakii strains. Fifty-four E. sakazakii strains appeared as fluorescent or chromogenic colonies on all four media that were assessed. Two strains showed colonies on NGTE medium and not on TPD media. In contrast, the remaining two strains showed colonies on TPD media and not on NGTE medium. None of the non-E. sakazakii strains showed fluorescent or chromogenic colonies on any of the evaluated media except E. vulneris, which showed colonies on TPD media and not on NGTE medium. This study demonstrated that the newly developed NGTE medium was not only equally efficient in promoting the growth of bacterial colonies when compared with the currently available media but also eliminated false positives, such as E. vulneris.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.551-563
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• 2022

L-asparaginase (E.C. 3.5.1.1) purified from bacterial cells is widely used in the food industry, as well as in the treatment of childhood acute lymphoblastic leukemia. In the present study, the Burkholderia pseudomallei L-asparaginase gene was cloned into the pGEX-2T DNA plasmid, expressed in E. coli BL21 (DE3) pLysS, and purified to homogeneity using Glutathione Sepharose chromatography with 7.26 purification fold and 16.01% recovery. The purified enzyme exhibited a molecular weight of ~33.6 kDa with SDS-PAGE and showed maximal activity at 50℃ and pH 8.0. It retained 95.1, 89.6%, and 70.2% initial activity after 60 min at 30℃, 40℃, and 50℃, respectively. The enzyme reserved its activity at 30℃ and 37℃ up to 24 h. The enzyme had optimum pH of 8 and reserved 50% activity up to 24 h. The recombinant enzyme showed the highest substrate specificity towards L-asparaginase substrate, while no detectable specificity was observed for L-glutamine, urea, and acrylamide at 10 mM concentration. THP-1, a human leukemia cell line, displayed significant morphological alterations after being treated with recombinant L-asparaginase and the IC₅₀ of the purified enzyme was recorded as 0.8 IU. Furthermore, the purified recombinant Lasparaginase improved cytotoxicity in liver cancer HepG2 and breast cancer MCF-7 cell lines, with IC₅₀ values of 1.53 and 18 IU, respectively.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.749-760
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• 2022

α-Galactosidase is a debranching enzyme widely used in the food, feed, paper, and pharmaceuticals industries and plays an important role in hemicellulose degradation. Here, T26, an aerobic bacterial strain with thermostable α-galactosidase activity, was isolated from laboratory-preserved lignocellulolytic microbial consortium TMC7, and identified as Parageobacillus thermoglucosidasius. The α-galactosidase, called T26GAL and derived from the T26 culture supernatant, exhibited a maximum enzyme activity of 0.4976 IU/ml when cultured at 60℃ and 180 rpm for 2 days. Bioinformatics analysis revealed that the α-galactosidase T26GAL belongs to the GH36 family. Subsequently, the pET-26 vector was used for the heterologous expression of the T26 α-galactosidase gene in Escherichia coli BL21 (DE3). The optimum pH for α-galactosidase T26GAL was determined to be 8.0, while the optimum temperature was 60℃. In addition, T26GAL demonstrated a remarkable thermostability with more than 93% enzyme activity, even at a high temperature of 90℃. Furthermore, Ca²⁺ and Mg²⁺ promoted the activity of T26GAL while Zn²⁺ and Cu²⁺ inhibited it. The substrate specificity studies revealed that T26GAL efficiently degraded raffinose, stachyose, and guar gum, but not locust bean gum. This study thus facilitated the discovery of an effective heat-resistant α-galactosidase with potent industrial application. Meanwhile, as part of our research on lignocellulose degradation by a microbial consortium, the present work provides an important basis for encouraging further investigation into this enzyme complex.