• Food Science and Preservation
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• v.24 no.5
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• pp.707-713
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• 2017

The objective of this study was to select yogurt starter from Korean traditional fermented foods. The 2 strains (KM24, KM32) among 50 strains of isolated lactic acid bacteria selected as starter based on milk clotting ability, antimicrobial activity against various pathogens, tolerance in artificial gastric and bile juice and growth in 10 % skimmed milk. The strains were identified as Lacobacillus plantarum (KM32) and Pediococcus pentosacesus (KM24) by 16S rRNA gene sequencing. Viable cell number of yogurt fermented with mixed strains (KM24 and KM32) was 9.66 log CFU/mL after fermentation for 48 h and maintained $10^9CFU/mL$ during fermentation for 72 h at $37^{\circ}C$. The pH and titratable acidity of mixed cultured yogurt were 4.25% and 0.83% after fermentation for 48 h at $37^{\circ}C$, respectively. The physico-chemical characteristics of mixed cultured yogurt after fermentation for 48 h were $38.45{\mu}g/mL$ (polyphenol content), 48.57% (DPPH radical scavenging activity) and 465.40 cp (viscosity), respectively. The mixed cultured yogurt maintained $10^9CFU/mL$ of lactic acid bacteria during storage 10 days at $4^{\circ}C$. The viable cell number of yogurt prepared with mixed culture(KM32+KM24) maintained higher and than that of control (L. casei) during storage. These results indicated the potential use of selected strains (KM32+KM24) isolated from kimchi as a yogurt starter with strong acid tolerance and probiotics properties.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.196-202
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• 2007

Mutations in the cystathionine ${\beta}$-synthase (CBS) gene cause homocystinuria, the most frequent inherited disorder in sulfur metabolism. CBS is the unique enzyme using both heme and pyridoxal 5-phosphate (PLP) for activity. Among the reported 140 mutations, one of the most common disease-causing alterations in human CBS is G307S mutation. To investigate the pathogenic mechanism of G307S by spectroscopic methods, we engineered the full length and the truncated G247S mutation of yeast CBS that is corresponding mutation to human G307S. Yeast CBS does not contain heme and thus gives a merit to study the spectroscopic properties. The UV-visible spectra of the purified full length and the truncated G247S yeast CBSs showed the total absence of PLP in the protein. The absence of PLP in G247S mutation was also confirmed by the PLP-cyanide adduct formation experiment, which was conducted by the incubation of the purified enzyme with KCN. The adducts were detected using a circular dichroism (CD) and a spectrofluorimeter. Radio isotope activity assay of full length and truncated G247S proteins also gave no activity. Our yeast G247S mutation data suggested that G307S might make the distortion of the active site so that cofactor PLP and substrate can not fit inside the active site. Our yeast CBS study addressed the reason why the G307S mutation in human CBS makes the enzyme inactive that consequently leads to severe clinical phenotype.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.334-340
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• 2014

Toxin-producing Bacillus cereus is the causative agent of two different types of food poisoning: the emetic and the diarrheal types. This study was conducted to investigate the presence of enterotoxin and emetic toxin genes in 263 B. cereus isolated from 619 different ready-to-eat food items. Hemolytic enterotoxins hblA, hblC, and hblD were detected in 85.6, 41.1, and 76.8%, respectively, of the B. cereus isolates. About 67.0% (175/263) of the isolates presented all of three genes. Non-hemolytic enterotoxins nheA, nheB, and nheC were detected in 100, 97.0, and 68.4% of the isolates, respectively. Approximately 90.0% (236/263) of the isolates presented all of these three non-hemolytic enterotoxin genes. Emetic toxin gene, CER, was detected in 132 of 263 (50.2%) isolates. Computer-assisted cluster analysis of Rep-PCR profiles showed a high genetic diversity among the isolates. All B. cereus isolates from food samples tested in this study carried at least 6 of 10 toxin genes.

• Journal of Technology Innovation
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• v.26 no.4
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• pp.199-232
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• 2018

There are increasing needs for understanding and fathoming of business management environment through big data analysis at industrial and corporative level. The research using the company disclosure information, which is comprehensively covering the business performance and the future plan of the company, is getting attention. However, there is limited research on developing applicable analytical models leveraging such corporate disclosure data due to its unstructured nature. This study proposes a text-mining-based analytical model for industrial and firm level analyses using publicly available company disclousre data. Specifically, we apply LDA topic model and word2vec word embedding model on the U.S. SEC data from the publicly listed firms and analyze the trends of business topics at the industrial and corporate levels. Using LDA topic modeling based on SEC EDGAR 10-K document, whole industrial management topics are figured out. For comparison of different pattern of industries' topic trend, software and hardware industries are compared in recent 20 years. Also, the changes of management subject at firm level are observed with comparison of two companies in software industry. The changes of topic trends provides lens for identifying decreasing and growing management subjects at industrial and firm level. Mapping companies and products(or services) based on dimension reduction after using word2vec word embedding model and principal component analysis of 10-K document at firm level in software industry, companies and products(services) that have similar management subjects are identified and also their changes in decades. For suggesting methodology to develop analysis model based on public management data at industrial and corporate level, there may be contributions in terms of making ground of practical methodology to identifying changes of managements subjects. However, there are required further researches to provide microscopic analytical model with regard to relation of technology management strategy between management performance in case of related to various pattern of management topics as of frequent changes of management subject or their momentum. Also more studies are needed for developing competitive context analysis model with product(service)-portfolios between firms.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.354-361
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• 2021

Understanding the phytotoxic mechanism of methyl bromide (MB), an essential fumigant during the quarantine and pre-shipment process, is urgently needed to ensure its proper use and reduce international economic losses. In a previous study, two main MB-induced toxic mechanisms such as reactive oxygen species (ROS) and auxin distribution were selected by analyzing transcriptomic analysis. In the study, a 3-week-old A. thaliana was supplied with 1 mM ROS scavengers [N-acetyl-L-cysteine (NAC) or L-glutathione (GSH)] and 1µM indole-3-acetic acid(IAA) three times every 12 h, and visual and gene expression assessments were performed to evaluate the reduction in phytotoxicity by supplements. Phytotoxic effects on the MB-4h exposed group were decreased with GSH application compared to the other single supplements and a combination of supplements at 7 days post fumigation. Among these supplements, GSH at a concentration of 1, 2, and 5mM was suppled to A. thaliana with MB-fumigation. During a long-term observation of 2 weeks after the fumigation, 5 mM GSH application was the most effective in minimizing MB-induced phytotoxic effects with up-regulation of HSP70 expression and increase in main stem length. These results indicated that ROS was a main key factor of MB-induced phytotoxicity and that GSH can be used as a supplement to reduce the phytotoxicity of MB.

• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.674-691
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• 2019

The aim of this study was to evaluate the anti-inflammatory effects of essential oils extracted from the wood of Chamaecyparis obtusa, Pinus densiflora, Pinus koraiensis, and Larix kaempferi. Essential oils were extracted by hydrodistillation, and their chemical components were determined by GC/MS. Major chemical components of these essential oils were ${\alpha}$-cadinol (19.25%), ${\tau}$-muurolol (14.20%), and ${\alpha}$-pinene (13.74%) in C. obtusa; ${\alpha}$-pinene (47.16%), longifolene (14.31%), ${\beta}$-phellandrene (11.78%), and ${\beta}$-pinene (11.02%) in P. densiflora; ${\alpha}$-pinene (13.49%) and longifolene (10.79%) in P. koraiensis, and geranyl linalool (23.58%) and ${\alpha}$-pinene (18.57%) in L. kaempferi. To evaluate the anti-inflammatory effects of essential oils, lipopolysaccharide (LPS)-induced RBL-2H3 mast cells were treated with these essential oils; then, the changes in the mRNA expression level of the cytokines IL-4 and IL-13 were examined. Further, degranulation was evaluated by measuring ${\beta}$-hexosaminidase release. After LPS-induced RBL-2H3 mast cells were exposed to $10^{-7}%$ of all types of essential oils, the gene expression levels of IL-4 and IL-13 within the cells remarkably decreased. The relative mRNA expression level of IL-4 was 69.6% in P. densiflora, 63.2% in P. koraiensis, 55.1% in C. obtusa, and 45.8% in L. kaempferi compared with that in the group treated with LPS. The mRNA expression level of L-13 should a similar trend. The inhibitory rate of IL-13 mRNA expression of P. densiflora, P. koraiensis, C. obtusa, and L. kaempferi was 57.8%, 57.1%, 51.1%, and 34.5%, respectively. ${\beta}$-Hexosaminidase release significantly decreased following the treatment with the four types of essential oils. The rate of ${\beta}$-hexosaminidase release were 38.1% C. obtusa; 33.0% P. densiflora; 27.4% P. koraiensis; and 9.1% L. kaempferi. Among all types of essential oils, that extracted from P. densiflora wood showed the highest anti-inflammatory activity. These results show that the tested essential oils exert an anti-inflammatory effect through the inhibition of degranulation and expression of cytokines.

• Journal of Science Education
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• v.47 no.2
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• pp.192-210
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• 2023

This study was intended to develop the plant molecular biology experimental program using Rapid-cycling Brassica rapa (RcBr) based on the teaching steps and teaching methods of the cognitive apprenticeship model and to determine its application effects. In order to improve a subject's cognitive function and expertise on molecular biology experiments, two themes composed of a total 8 class sessions were selected: 'Identification of DFR gene in purple RcBr and non-purple RcBr' and 'Identification of RcBr's genetic polymorphism site using the DNA profiling method'. Research subjects were 18 pre-service teaching majors in biology education of H University in Chungbuk, Korea. The effectiveness of the developed program was verified by analyzing the enhancement of 'cognitive function' related to the use of molecular biology knowledge and technology, and the enhancement of 'domain-general metacognitive abilities.' The effect of the developed program was also determined by analyzing the task flow diagram provided. The developed program was effective in improving the cognitive functions of the pre-service teachers on the use of knowledge and technology of molecular biology experiments. It was especially effective to improve the higher cognitive function of pre-service teachers who did not have the previous experience. The developed program also showed a significant improvement in the task of metacognitive knowledge and in the planning, checking, and evaluation of metacognitive regulation, which are sub-elements of domain-general metacognitive abilities. It was found that the developed program's self-test activity could help the pre-service teachers to improve their metacognitive regulation. Therefore, this developed program turned out to be helpful for pre-service teachers to develop core competencies needed for molecular biology experimental classes. If the teaching and learning materials of the developed program could be reconstructed and applied to in-service teachers or high school students, it would be expected to improve their metacognitive abilities.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.200-209
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• 2012

The effect of water temperature, salinity and water column nutrient contents on pigment composition and concentration of purple lavers were studied at the main purple lavers production areas in Southwestern coast of Korea, during January to March, 2011. Water temperature was between 3.0 and $11.3^{\circ}C$. Salinity range was between 32.7 and 34.7, those were lower St. 1 and St. 6, which were at close to the seashore. Water column dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and silicate concentrations were $1.73{\sim}12.84{\mu}M$, $0.07{\sim}0.67{\mu}M$ and $4.93{\sim}18.29{\mu}M$, respectively. Chl a concentration was between 0.41 and $9.14{\mu}g\;L^{-1}$, and it was the highest at St. 1 during January. Photosynthetic pigment of fucoxanthin was dominant at all sites, which showed its highest concentration ($0.06{\sim}3.41{\mu}g\;L^{-1}$) at St. 1 on January. Water column DIN concentration was higher at January during low salinity period at all sites, but it was low at St. 1. Photosynthetic pigment of Chl a, PE and PC concentration of porphyra blades was between $1,173{\sim}8,124{\mu}g\;DW\;g^{-1}$, $3,281{\sim}10,076{\mu}g\;DW\;g^{-1}$, $388{\sim}1,346{\mu}g\;DW\;g^{-1}$, respectively. The concentration was relatively high at the St. 2 and St. 3. The pigment concentration of porphyra blades was higher at only Porphyra yezoensis was cultured than at Porphyra yezoensis and Porphyra seriata were cultured. The pigment concentration of porphyra blades was higher at St. 2 and St. 3 in only Porphyra yezoensis was cultured. This study shows that pigment concentration of porphyra blades may depend on habitat environment and culture methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.161-171
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• 2020

Direct seeding is one of the rice seedling establishment methods that is increasingly being practiced by farmers to save labor and reduce costs. However, this method often causes poor germination under flooding conditions after sowing. In this study, we developed japonica elite lines with quantitative trait loci (QTL) associated with anaerobic germination (AG) tolerance to overcome poor germination and seedling establishment in wet direct seeding. The QTL introgression lines were developed from a cross between weedy photoblastic rice as the AG donor and the Nampyeong variety via phenotypic and genotypic selection. Compared to Nampyeong, the survival rates of the selected lines were improved by approximately 50% and 240% under field and greenhouse conditions, respectively. To improve selection efficiency by marker assisted selection, the QTL markers associated with AG tolerance were converted to cleaved amplified polymorphic sequence markers designed based on next-generation sequence analysis. These lines retained similar agronomic traits and yield potential to the parent, Nampyeong. Among these lines, we selected the most promising line, which exhibited high survival rate and good agricultural traits under flooding conditions and named the line as Jeonju643. This line will contribute to breeding programs aiming to develop rice cultivars adapted to wet direct seeding. This study demonstrates the successful application of marker-assisted selection to targeted introgression of anaerobic genes into a premium quality japonica rice variety.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.105-119
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• 2012

Indigenous bacteria isolated from contaminated sites play important roles to remediate contaminated groundwater. Chromium has the most stable oxidation states. Cr(VI) is toxic, carcinogenic, and mobile, but Cr(III) is less toxic and immobile. In this study, indigenous microorganism (MMPH-0) was enriched from Cr(VI) contaminated groundwater, and identified by 16S rRNA gene analysis. Using MMPH-0, the effect of stimulating with e-donors (glucose, lactate, acetate, and no e-donor control), respiration conditions, biomass, tolerance, and geochemical changes on Cr(VI) reduction were investigated in batch experiments for 4 weeks. The changes of Cr(VI) concentration and geochemical conditions were monitored using UV-vis-spectrophotometer and Eh-pH meter. And the morphological and chemical characteristics of MMPH-0 and precipitates in the effluents were characterized by TEM-EDS and SEM-EDS analyses. MMPH-0 (Enterobacter aerogenes) was able to tolerate up to 2000 mg/L Cr(VI) and reduce Cr(VI) under aerobic and anaerobic conditions. MMPH-0 performed faster and higher efficiency of Cr(VI) reduction with electron donors (over 70% after 1 week with e-donor, 10-20% after 4 weeks without e-donor). The changes of Eh-pH in effluents showing the tendency from oxidizing to reducing condition and a bit of acidic change in pH due to microbial oxidation of organic matters donating electrons and protons suggested the roles of MMPH-0 on Cr(VI) in the contaminated water catalyzing to transit geochemical stable zone for more stable $Cr(OH)_3$ or Cr(III) precipitates. TEM/SEM-EDS analyses of MMPH-0 and precipitates indicate direct and indirect Cr(VI) reduction: extracellular polymers capturing Cr component outside cells. These results suggested diverse indigenous bacteria and their biogeochemical reactions might enhance more effective and feasible remediation technology of redox sensitive heavy metals in metal-contaminated in groundwater.