• Horticultural Science & Technology
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• v.31 no.1
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• pp.72-79
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• 2013

Inactivation of the gene coding for dihydroflavonol 4-reductase (DFR) is responsible for the color difference between red and yellow onions (Allium cepa L.). Two inactive DFR-A alleles, DFR-$A^{PS}$ and DFR-$A^{DEL}$, were identified in our previous study. A functional marker was developed on the basis of the premature stop codon that inactivated the DFR-$A^{PS}$ allele. A derived cleaved amplified polymorphic sequences (dCAPS) primer was designed to detect the single nucleotide polymorphism, an A/T transition, which produced the premature stop codon. Digested PCR products clearly distinguished the homozygous and heterozygous red $F_2$ individuals. Meanwhile, to develop a molecular marker for detection of the DFR-$A^{DEL}$ allele in which entire DFR-A gene was deleted, genome walking was performed and approximately 3 kb 5' and 3' flanking sequences of the DFR-$A^R$ coding region were obtained. PCR amplification using multiple primers binding to the extended flanking regions showed that more of the extended region of the DFR-A gene was deleted in the DFR-$A^{DEL}$ allele. A dominant simple PCR marker was developed to identify the DFR-$A^{DEL}$ allele using the dissimilar 3' flanking sequences of the DFR-A gene and homologous DFR-B pseudogene. Distribution of the DFR-$A^{PS}$ and DFR-$A^{DEL}$ alleles in yellow onion cultivars bred in Korea and Japan was surveyed using molecular makers developed in this study. Results showed predominant existence of the DFR-$A^{PS}$ allele in yellow onion cultivars.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.549-555
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• 2014

The geographical origin of commercial red ginseng concentrate was studied using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The ginsenoside content of domestic and Chinese red ginseng concentrates was determined. Four types of suspected origin samples could be selected this technique. The LC-MS/MS data were statistically analyzed on the basis of canonical function analysis and principal component analysis. Domestic and Chinese samples could be discriminated via canonical function analysis using posterior probability. In addition, the mixture ratio (Korean or Chinese origin) of the unknown origin specimen could be predicted based on the relationship between the mixing concentration of red ginseng concentrates and principal component 1.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.500-506
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• 2017

Kimchi cabbage is one of the four major vegetable crops in Korea. The total annual production of kimchi cabbage, the main material of kimchi, was 20,559 tons in 2015. Kimchi cabbage is one of the majer crops produced by farmers which accounts for about 80% of the total leaf vegetable production in Korea. As the consumption of environmental-friendly agricultural products increases, food safety is one of the major public health concerns. We analyzed the biological hazards of kimchi cabbage produced by two types of cultivation methos such as organic farming and conventional farming using various culture media and microscopy. A total of 432 samples were analysed for presence of sanitary indicator microorganisms (aerobic plate count, coliform count, yeast & mold) and food-borne pathogens (Staphylococcus aureus, environmental Listeria, Bacillus cereus). The population of sanitary indicating microorganisms and food borne pathogens was under 5 Log CFU/g in all tested samples. The results of total microorganism numbers of leaf surface showed a positive correlation to those of soil samples. Additionally, we examined chemical factors such as pesticide residues and heavy metals in soil samples. All tested samples did not shown contamination levels higher than the standard limit.

• Journal of Drive and Control
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• v.13 no.1
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• pp.1-9
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• 2016

Nowadays automatic transmission equipped vehicles prevail in construction and agricultural equipment due to their convenience in driving and operation. Though domestic vehicle manufacturers install imported electronic controlled transmissions at present, overseas products will be replaced by domestic ones in the near future owing to development efforts over the past 10 years. For passenger cars, there are many kinds of shift control algorithms that enhance the shift quality such as feedback and learning control. However, since shift control technologies for heavy duty vehicles are not highly developed, it is possible to improve the shift quality with an organized control method. A feedback control algorithm for neutral-into-gear shift, which is enabled during the inertia phase for the master clutch slip speed to track the slip speed reference, is proposed based on the power transmission structure of TH100. The performance of the feedback shift control is verified by a vehicle test which is implemented with firmware embedded TCU. As the master clutch engages along the predetermined speed trajectory, it can be concluded that the shift quality can be managed by a shift time control parameter. By extending the proposed feedback algorithm for neutral-into-gear shift to gear change and shuttle shift, it is expected that the quality of the shift can be improved.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.33-39
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• 2010

Recently. dyeing by harmless natural materials has received much attention due to the side-effects occurred from dyeing by synthetic dyes. In this study, we examined the effect of extracts of Pueraria thunbergiana (P. thunbergiana) roots, which are treated as natural products as well as agricultural wastes, on the hair dyeing by measuring dyeing interval, temperature, density changes, mordant and chromatic faction. The hair dyeing by the extracts significantly reduced hair damage and kept cuticle of hair softer than that by synthetic dyes. In addition, since a mordant is one of the necessary additives in dyeing, the role of a mordant was studied and concluded to be a supplementary substance based on the results that the hair dyeing by the extracts of P. thunbergiana roots alone was much darker than the others. Taken together, the data presented in this study suggest that the extracts of P. thunbergiana roots are is less damageable to hair and thus can be more safely applicable to hair dyes than that by synthetic dyes.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.421-428
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• 1999

Potassium (K) released from weathering of biotite in soils has been recognized as one of major K-sources for plant growth. Sand size biotite in a soil-saprolite-parent rock profile developed under temperate climate was studied in terms of morphological, mineralogical, and chemical changes according to depth employing petrographic and electron microscopes. X-ray diffraction, and electron microprobe. Biotite showed discoloring from black to goldish white and loss paleochroism with decreasing depth. Both edge and layer weatherings of biotite showed in this study. Hexagonal holes and cracks on (001) plane of weathered biotite grains were observed and their members increased with increasing weathering degree. Biotite was altered to kaolinite with or without intermidiate products such as hydrobiotite, degraded biotite, and illite. Average chemical composition of weathered biotite changed to that of katolinite with decreasing depth: increasing concentrations of silicon (Si) and aluminum (Al) and decreasing concentrations of potassium (K), iron (Fe), magnesium (Mg), manganese (Mn), and taitanium (Ti).

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.923-932
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• 2019

Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce $\text\tiny{L}$-phenylalanine ($\text\tiny{L}$-Phe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36-fold of the strain xllp1 (45.0 g/l). Moreover, the $\text\tiny{L}$-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

• Entomological Research
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• v.48 no.6
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• pp.533-539
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• 2018

The RNA interference (RNAi) has been considered as an important genetic tool and applied to develop a new living modified (LM) crop trait which is an improvement of nutrient quality or pest management. The RNAi of DvSnf7 has been used for resistance to LM maize and the Western Corn Rootworm which is a major agricultural pest for the US Corn Belt. Most of the environmental risk assessments (ERA) of double strand RNA (dsRNA) have been performed using in vitro transcript products, and not in vivo expressed product. A large amount of dsRNA was required for the acute toxicity assay of water fleas. Therefore development of massive dsRNA purification techniques is critical. Daphnia, a freshwater microcrustacean, is a model organism for studying cellular and molecular mechanism involved in life history traits and ecotoxicology. In this study, we established the massive dsRNA purification method using Escherichia coli and implemented acute toxicity assays to Daphnia magna. As a result, the present RNase A and DNase I, dsRNA was efficiently purified without any special techniques or equipment. Even though purified dsRNA existed during the acute toxicity test, lethality or abnormal behavior were not observed in D. magna. These results indicated that GFP and DvSnf7 dsRNA were not significantly affected to D. magna due to their lack of sequence matching in its genome. The purification method of dsRNA and the acute toxicity assay of water fleas using purified dsRNA would be suitable for the toxicological studies of LMOs to aquatic non-target organisms.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.139-150
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• 2019

This study aimed to determine the suitable point of sale and consumption of different quality grade (QG) Hanwoo short loin during aging period, based on physicochemical, sensory, and microbiological quality. Short loins obtained from the carcasses of 13 Hanwoo steers and 2 bulls with 5 different QGs (1++, 1+, 1, 2, and 3) were analyzed over 28 d. QG and aging time had significant effect on water holding capacity, color, shear force, total volatile basic nitrogen (TVBN) content, and sensory traits. Higher QG groups generally exhibited a lower shear force, nucleotide content, and water holding capacity, and higher $L^*$, $a^*$, and $b^*$ values. Acceptable tenderness (shear force <5.4 kg) in QG 1++, 1+, 1, and 2 was achieved on days 7, 14, 16, and 18, respectively, and QG 3 showed a shear force of 6.8 kg, even after 28 d. Regardless of QG, TVBN content below threshold levels (20-30 mg%) was observed throughout the 28 d aging period, while total plate counts above 7 Log CFU/g were seen at 21 d. In conclusion, it is recommended that Hanwoo beef with QG 1++, 1+, and intermediate QG (1 and 2) should be sold or consumed between 7 and 21, 14 and 21, 16 and 21 d, respectively. Beef with QG 3 should be sold or consumed within 21 d, based on microbial growth, even though it has not achieved desirable tenderness. For this reason, an additional tenderizing process is recommended before this beef is ready for consumption.

• The Korean Journal of Food And Nutrition
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• v.32 no.1
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• pp.33-40
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• 2019

The purpose of this study was to evaluate the antioxidant and hepatocyte protective effects of guava (Psidium guajava L.) leaves cultivated in Korea. The contents of the total polyphenol of the extract was 271.57 mg gallic acid equivalent (GAE)/g residue. Antioxidant activities of leaf extract were evaluated by examining the free radical scavenging ability. 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ${\alpha}-{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl (DPPH) free radical scavenging activities of the extract were 1133.23 mg trolox equivalent antioxidant capacity (TEAC)/g residue and 721.68 mg TEAC/g residue, respectively. The hepatocyte protective effect of guava leaf extract was examined in HepG2 cells. Against tert-butyl hydroperoxide (TBHP), the viability of HepG2 cells were increased by the treatment of leaf extract. In addition, guava leaf extract led to the inhibition of reactive oxygen species (ROS) generated in HepG2 cells. The leaf extract increased the activity of glutathione (GSH), glutathione reductase (GR), and glutathione peroxidase (GPx) against oxidative stress. These results suggested that guava leaves might be regarded as a potential source natural antioxidant and a hepatoprotective material.