• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.77-77
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• 2019

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1519-1528
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• 2017

Foodborne contamination and salmonellosis caused by Salmonella Enteritidis (S. Enteritidis) are a significant threat to human health and poultry enterprises. Outer membrane vesicles (OMVs), which are naturally secreted by gram-negative bacteria, could be a good vaccine option because they have many biologically active substances, including lipopolysaccharides (LPS), outer membrane proteins (OMPs), and phospholipids, as well as periplasmic components. In the present study, we purified OMVs derived from S. Enteritidis and analyzed their characteristics through silver staining and sodium dodecyl sulfate polyacrylamide gel electrophoresis. In total, 108 proteins were identified in S. Enteritidis OMVs through liquid chromatography tandem mass spectrometry analysis, and OMPs, periplasmic proteins, and extracellular proteins (49.9% of total proteins) were found to be enriched in the OMVs compared with bacterial cells. Furthermore, native OMVs used in immunizations by either the intranasal route or the intraperitoneal route could elicit significant humoral and mucosal immune responses and provide strong protective efficiency against a lethal dose (~100-fold $LD_{50}$) of the wild-type S. Enteritidis infection. These results indicated that S. Enteritidis OMVs might be an ideal vaccine strategy for preventing S. Enteritidis diseases.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.130-141
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• 2017

We evaluated the field application feasibility that biologically derived substances (Naphthoquinone derivate: NQ 2-0) can be used for the eco-friendly mitigation of natural harmful cyanobacterial blooms in freshwater. We conducted a 30 ton scale mesocosm experiment to investigate the effects of NQ 2-0 on biotic and abiotic factors in water collected from Gi-heung reservoir. In the mesocosm experiments, the abundance of Microcystis sp. was continuously increased in the control. However, the Microcystis sp. cell density was sharply decreased on the $10^{th}$ day. In the treatment, NQ 2-0 showed the strong and selective algicidal activity toward the target cyanobacteria (Microcystis sp.). Accordingly, the algicidal activity of NQ 2-0 compound increased gradually until $10^{th}$, $15^{th}$ days and algal biomass was decreased to 99.4 and 100 %, respectively. NQ 2-0 compound was not only selective algicidal activity but also the growth of other phytoplankton and increased the Shannon-Wiener diversity index of phytoplankton. In the mesocosm experiments, the dynamics of biotic (bacteria, heterotrophic nanoflagellate, ciliates, zooplankton) and abiotic (water temperature, dissolved oxygen, pH, conductivity, nutrients) factors remained unaffected. These results suggest that NQ 2-0 could be a selective and ecologically safe algicide to mitigate harmful cyanobacterial blooms. In addition, it is believed that NQ 2-0 will play a major role in forming a healthy aquatic ecosystem by facilitating habitat and food supply of aquatic organisms.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.114-126
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• 2020

Bloom-forming toxic cyanobacteria Microcystis spp. are common in the summer season in temperate freshwater ecosystems. Often, it leads to the degradation of water quality and affects the quality of drinking water. In a previous study, NQ (naphthoquinone) compounds were shown to be effective, selective, and ecologically safe algicides for Microcystis spp. blooms. To analyze the superiority of developed NQ derivatives, we conducted a microcosm experiment using clay, which is frequently used in South Korea. Similar to previous studies, the NQ 40 and NQ 2-0 compounds showed high algicidal activities of 99.9% and 99.6%, respectively, on Microcystis spp. at low concentrations (≥1 μM) and enhanced phytoplankton species diversity. However, when treated with clay, a temporary algicidal effect was seen at the beginning of the experiment that gradually increased at the end. In addition, treatment with the NQ compounds did not affect either the abiotic or biological factors, and similar trends were observed with the control. These results showed that the NQ 2-0 compound was more effective, with no ecosystem disturbance, and more economical than the currently used clay. These results suggest that NQ 2-0 compound could be a selective, economically and ecologically safe algicide to mitigate harmful cyanobacterial blooms in the field.

• KSBB Journal
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• v.32 no.2
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• pp.117-123
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• 2017

Maple tree is a useful medical plant for obtaining bioactive materials such as pharmaceutics, cosmetics, food additive, etc., and there are 16 species of native maple trees in Korea. In this study, we evaluated the antioxidant activity of sap and crude extracts of Acer mono Max, a representative maple species. The crude extracts were obtained by solvent extraction (water, ethanol, and ethyl acetate) from its branches (bark and xylem). The phenolic contents and radical scavenging capacities of the extracts and the sap were evaluated in terms of half maximal effective concentration ($EC_{50}$) and kinetics by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The ethanol extracts showed the highest extraction yield, phenolic contents and antioxidant activity, and bark extracts showed better antioxidant activity than xylem extracts. The antioxidant activity of the sap was very low, but the $EC_{50}$ of ethanol and ethyl acetate extracts ranged from 68 to $79{\mu}g/mL$, similar to that ($60{\mu}g/mL$) of the control, butylated hydroxytoluene (BHT). The DPPH radical scavenging rate ($220{\sim}760{\mu}M/min$) and the second-order reaction rate constant ($6.48{\sim}7.04L/g{\cdot}min$) of these extracts were better than those of BHT ($55{\sim}370{\mu}M/min$ and $3.60L/g{\cdot}min$). These results suggest that A. mono Max. is one of the useful bioresources for obtaining antioxidant biologically active substances, and it is possible to obtain physiologically active substances from by-product of its pruning while minimizing the effect on the growth of the tree.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.25-32
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• 2021

Phytochemicals include plant-derived natural products that promote and improve the human metabolism and physiological activity, and there is a lot of research to find the value of the molecules is in progress. Likewise, we obtained 288 fractions of Capsicum annuum L. extract in less than 20 h using HPLC/SPE/HPLC coupling experiment through Sepbox system, an effective separation system to search for active substances in natural resources and ensure efficacy and reliability. Therefore, this experiment allowed rapid identification of biologically active molecules from the extract compared to traditional separation processes. Of the above fractions, eight fractions showed the α-glucosidase inhibitory (AGI) activity and subsequent LC-MS analysis revealed one of the active molecules as luteolin 7-O-glucoside. In addition, we proved the increase in AGI activity according to deglycosylation of flavonoid glycoside. Therefore, this study suggests that the Sepbox system can quickly separate and identify active components from plant extract, and is an effective technique for finding new active substances.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.572-580
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• 2018

Biologically active substances including gamma-aminobutryric acid (GABA) were added into whey by co fermentation using Bacillus subtilis HA and Lactobacillus plantarum EJ2014. The first fermentation using B. subtilis HA with 5% monosodium glutamate (MSG) and 2% glucose enhanced the production of poly-${\gamma}$-glutamic acid (PGA), resulting in higher consistency of $4.09Pas^n$ as well as whey protein peptides. After the second fermentation using L. plantarum EJ2014, the remaining MSG (3.40%) as a precursor was completely converted to 2.21% GABA. Furthermore, the lactose content in whey decreased from 6.73 to 3.68% after co-fermentation, and the tyrosine content increased from 20.47 to 38.24%. Peptides derived of whey proteins were confirmed by SDS-PAGE. Viable cell counts of B. subtilis and L. plantarum were 5.83 log CFU/mL and 9.20 log CFU/mL, respectively. Thus, co-fermentation of whey could produce the novel food ingredient fortified with biologically active compounds including GABA, ${\gamma}$-PGA, peptides, and probiotics.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1178-1187
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• 2000

Many immunostimulating substances have been developed to improve immunity of domestic animals, although their exact mode of action and effects are not clearly defined, and they are now widely used in feed industry. Bacterial lipopolysaccharides, called endotoxin, in particular may have a profound effect not only on the immune system but also on macrophages of the reticuloendothelial system. Glucans from a variety of yeast cell wall have been shown to stimulate both specific and non-specific immune responses and to increase growth performance in pigs. Recently, there has been great interest in the role of complex carbohydrates in disease prevention and treatment. Mannanoligosaccharide is a glucomannoprotein complex derived from the cell wall of yeast. Generally, it was also known that the deficiencies of some major vitamins (vitamin A, E and C) and minerals (chromium and selenium) lead to impaired immune system and, as a result, immune function is depressed and recovery delayed. On the other hand, many researchers suggested that one possible reason for the superior performance observed in pigs fed plasma protein may be because of the presence of biologically active plasma proteins (e.g., immunoglobulins) which are known to contribute to the health of the starter pig. And, immunoglobulins present in plasma protein have been implicated as contributing to the overall immunocompetence of the newborn pig. Other immunostimulants, lactoferrin and lysozyme, mainly found in milk and egg white, have been known as having bacteriocidal and bacteriolytic effect. When considering practical use of immunostimulants, the concept of using immunostimulants is new to many people and, in most cases, it is poorly understood how and why such compounds act, and how they should be used in practice. Therefore, in order to clarify the reason for discrepancies in results, special attention should be paid to the dose/response relationship of immunostimulants and the duration of the effect.

• Korean Journal of Acupuncture
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• v.38 no.1
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• pp.32-42
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• 2021

Objectives : In this study, we investigated the neuroprotective effects of ethanol extract of Lonicera japonica flower buds (EELJ) on glutamate-induced neurotoxicity in mouse hippocampus-derived neuronal HT22 cells. Methods : After analyzing the cytoprotective effect of EELJ on glutamate in HT22 cells, the inhibitory effect of apoptosis was studied using flow cytometry. In order to analyze the antioxidant efficacy of EELJ, the levels of reactive oxygen species (ROS) and glutathione (GSH) were investigated, and the effects on the activities of superoxide dismutase (SOD) and catalase (CAT) were also analyzed. Furthermore, the effect of EELJ on the expression of apoptosis regulators such as Bax and Bcl-2 in glutamate-treated HT22 cells was investigated. Results : According the current results, pretreatment with EELJ significantly reduced glutamate-induced loss of cell viability and release of lactate dehydrogenase. EELJ also markedly attenuated glutamate-induced generation of intracellular ROS, which was associated with increased levels of GSH, and activity of SOD and CAT in glutamate-stimulated HT22 cells. In addition, EELJ was strikingly inhibited glutamate-induced apoptosis in HT22 cells. Furthermore, the expression of pro-apoptotic Bax was increased and the expression of anti-apoptotic Bcl-2 was decreased in glutamate-treated HT22 cells, while in the presence of EELJ, their expressions were maintained at the control levels. Conclusions : These findings indicate that EELJ protects glutamate-induced cytotoxicity in HT22 hippocampal neurons through antioxidant activity. Therefore, although identification of biologically active substances of EELJ and re-evaluation through animal experiments is necessary, this natural substance is a promising candidate for further research in preventing and treating oxidative stress-mediated neurodegenerative diseases.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.72-81
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• 2020

Blooms of the small centric diatom Stephanodiscus is quite occasional in winter season in temperate freshwater ecosystems. Often, it leads to degradation of water quality and affects quality of supplied drinking water. In previous studies, naphthoquinone (NQ) compounds have been shown to be effective and selective for controlling winter bloom species Stephanodiscus hantzschii. We conducted a 5 ton scale mesocosm experiment to investigate the effects of NQ on native Stephanodiscus sp. collected from Nakdonggang River in water. After treatment with NQ 4-6 compound (0.2 μM), the cell density of Stephanodiscus sp. was rapidly reduced from 5 × 10³ cells mL^-1 to 0.2 × 10³ cells mL^-1 for 10 days. Additionally, NQ 4-6 compound did not affect physicochemical factors (water temperature, dissolved oxygen, pH, conductivity, nutrients) and biological factors (bacteria, heterotrophic nanoflagellates, zooplankton). Therefore, these findings suggest that the NQ 4-6 compound has potential as an alternative algicidal substances to effectively mitigate natural Stephanodiscus sp. blooms, and the application of NQ 4-6 compound will restore the healthy aquatic ecosystems.