• Korean Journal of Poultry Science
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• v.42 no.2
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• pp.157-167
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• 2015

We compared the degrees of stress response of 12 domestic purebred chicken strains that have been bred at National Institute of Animal Science, RDA, Korea since 1980. As a physiological marker of stress response, the expression levels of heat shock protein (HSP)-70, HSP-$90{\alpha}$, HSP-$90{\beta}$, hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes and telomere length were measured by quantitative real-time polymerase chain reaction using the lymphocytes of 1,101 chickens. There was significant difference in HSP-70, HSP-$90{\alpha}$, HMGCR expression and telomere length among the strains. There was also significant difference in HSP-$90{\alpha}$, HSP-$90{\beta}$, and HMGCR expression between male and female chickens. Different age groups of chicken exhibited different expression levels of HSP-70, HSP-$90{\alpha}$ and telomere length. The results of the HSPs expression level suggested that, the strains of R, L and Y were highly resistant to stress, whereas the strains of S, O and W were susceptible to stress. Although the statistical differences in some of HSPs gene expression existed between genders, the HSP expression results varied in different strains that some opposed to the others, and there might be interaction between strains and genders, which conclude that there was no difference in stress response between male and female chickens. Moreover, despite of significant difference in some of HSPs expression level, it was considered that there was no difference in stress response between ages due to the inconsistent trends among HSP markers.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.409-415
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• 1985

This study has been carried out in order to investigate the bacterial quality of fish meat paste products and the characteristics of isolated thermodurics from the products. Twenty samples of crab-flavored fish stick (Kematsal), 23 samples of plate fish meat paste (Panomuk, Kamaboko), 5 samples of fried fish meat paste (Tigimomuk), 2 samples of roasted fish meat paste (Puduromuk, Chikuwa), 20 samples of fish sausage were collected from processing plants and supermarkets in Pusan, Korea during the period from May to October in 1984. The results obtained are as follows. Amont the samples collected from supermarkets, roasted fish meat paste and fried fish meat paste marked hish counts in coliforms and fungi while very low in the samples of crab-flavored fish stick and plate fish meat paste. Salmonella was not detected in all the samples examined and Staphylococcus aureus was detected only in fried fish meat paste, Thermoduric bacteria were detected less than 10$^2$/g in the samples of crab-flavored fish stick and plate fish meat paste, which might come from subsidiary materials such as starch and seasonings. Among the isolated bacteria, distribution of the proteolytics were more than 87％ and the lipolytics were less than 20％. Gram positive bacteria was more than 70％ in crab-flavored fish stick and plate fish meat paste, 47.3％ in fried fish meat paste. And rod in shape was almost more than 90％ in all the samples. The most heat resistant bacterium isolated from the samples was identified as a Bacillus licheniformis(named B. licheniformis CR-11). The strain showed strong proteolytic activity and also grew well at above 2$0^{\circ}C$. The growth rate and generation time of CR-11 strain were 0.31 hr$^{-1}$ , 2.24 hr at 2$0^{\circ}C$, 0.64 hr$^{-1}$ , 1.09 hr at 3$0^{\circ}C$ and 0.78 hr$^{-1}$ , 0.89 hr at 35$^{\circ}C$. Heat resistance value of the spores of CR-11 strain suspended in phosphate buffer solution was D$_{85}$ $^{\circ}C$=41.9 min, D$_{90}$ $^{\circ}C$=27.9 min, D$_{95}$ $^{\circ}C$=10.2 min, D$_{100}$ $^{\circ}C$=4.3 min (Z=13.8$^{\circ}C$)

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.277-289
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• 1998

To establish a system for sperm swim-up separation through sucrose layer, indiscreet sperm migration should sufficiently to block but movement of sperm shouldn't inhibit. Thus, the effects of sucrose levels in sucrose layer, incubation times and types of sucrose layer on sperm separation were examined. And the results obtained were as follows; 1. Layer of 10mM sucrose inhibited sperm swim-up migration through sucrose layer. 2. Incubation for 25 minutes without sucrose layer significantly increased sperm swim-up migration. However, incubation for 10 minutes to induce swim-up through sucrose layer significantly stimulated sperm migration and maintained sperm movement. 3. There was no significant difference between Type I and Type II in barrier effect of sucrose layer. However, sucrose layer of Type II with shorter distance of barrier was efficient for sampling. To elucidate a function of follicular fluid on sperm chemotaxis using in vitro system of sucrose layer of Type II and incubation for 10 minutes, the effects of dilution, heat treatment, and protein and lipid extracts of follicular fluid on sperm swim-up separation were examined. And the results obtained were as follows; 4. Follicular fluid stimulated sperm migration and movement, and significantly-attracted capacitated-sperm at 10% level. 5. Follicular fluid heated at 55$^{\circ}C$ for 30 minutes maintained the effect of follicular fluid stimulating sperm migration and movement. 6. Follicular protein stimulated sperm movement that was reduced by filtration of the protein. 7. Follicular lipid didn't significantly stimulate sperm migration and movement. 8. Both of follicular protein and lipid reduced the effect of follicular fluid stimulating sperm migration and movement. In conclusion, sucrose layer could be used for a barrier against indiscreet sperm migration by swim-up. And follicular fluid stimulated migration and movement of sperm and attracted capacitated-sperm through sucrose layer. Especially, heat-resistant protein of follicular fluid stimulated sperm migration.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.438-442
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• 2005

Granule swelling is essential phenomenon of starch gelatinization in excess water, and characteristic of heated starch dispersion depends largely on size and distribution of swelled starch granule. Although swelling characteristic of starch granules depends on type of starch, heating rate, and moisture content, influence of heating rate on swelling phenomenon of starch granule has not been fully discussed, because constant heating rate of starch dispersion cannot be obtained by conventional heating method. Ohmic heating, electric-resistant heat generation method, applies alternative current to food materials, through which heating rate can be easily controlled precisely and conveniently at wide range of constant heating rates. Starch dispersion heated at low heating rates below $7.5^{\circ}C/min$ showed Newtonian fluid behavior, whereas showed pseudoplastic behavior at heating rates above $16.4^{\circ}C/min$. Apparent viscosity of starch dispersion increased linearly with increasing heating rate, and yield stress was dramatically increased at heating rates above $16.4^{\circ}C/min$. Average diameter of corn starch granules during ohmic heating was dramatically increased from $30.97\;to\;37.88\;{\mu}m$ by increasing heating rate from $0.6\;to\;16.4^{\circ}C/min$ (raw corn starch: $13.7\;{\mu}m$). Hardness of starch gel prepared with 15% corn starch dispersion after heating to $90^{\circ}C$ at different heating rates decreased gradually with increasing heating rate, then showed nearly constant value from $9.4\;to\;23.2^{\circ}C/min$. Hardness increased with increase of heating rate higher than $23.2^{\circ}C/min$.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.1-9
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• 2006

Peroxiredoxins (Prxs) are ubiquitously distributed and play important functions in diverse cellular signaling systems. The proteins are largely classified into three groups, such as typical 2-Cys Prx, atypical 2-Cys Prx, and 1-Cys Prx, that are distinguished by their catalytic mechanisms and number of Cys residues. From the three classes of Prxs, the typical 2-Cys Prx containing the two-conserved Cys residues at its N-terminus and C-terminus catalyzes $H_2O_2$ with the use of thioredoxin (Trx) as an electron donor. During the catalytic cycle, the N-terminal Cys residue undergoes a peroxide-dependent oxidation to sulfenic acid, which can be further oxidized to sulfinic acid at the presence of high concentrations of $H_2O_2$ and a Trx system containing Trx, Trx reductase, and NADPH. The sulfinic acid form of 2-Cys Prx is reduced by the action of sulfiredoxin which requires ATP as an energy source. Under the strong oxidative or heat shock stress conditions, 2-Cys Prx in eukaryotes rapidly switches its protein structure from low-molecular-weight species to high-molecular-weight protein structures. In accordance with its structural changes, the protein concomitantly triggers functional switching from a peroxidase to a molecular chaperone, which can protect its substrate denaturation from external stress. In addition to its N-terminal active site, the C-terminal domain including 'YF-motif' of 2-Cys Prx plays a critical role in the structural changes. Therefore, the C-terminal truncated 2-Cys Prxs are not able to regulate their protein structures and highly resistant to $H_2O_2$-dependent hyperoxidation, suggesting that the reaction is guided by the peroxidatic Cys residue. Based on the results, it may be concluded that the peroxidatic Cys of 2-Cys Prx acts as an '$H_2O_2$-sensor' in the cells. The oxidative stress-dependent regulation of 2-Cys Prx provides a means of defense systems in cells to adapt stress conditions by activating intracellular defense signaling pathways. Particularly, 2-Cys Prxs in plants are localized in chloroplasts with a dynamic protein structure. The protein undergoes conformational changes again oxidative stress. Depending on a redox-potential of the chloroplasts, the plant 2-Cys Prx forms super-molecular weight protein structures, which attach to the thylakoid membranes in a reversible manner.

• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.95-105
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• 2020

This study presents the production characteristics and physiological characteristics of five Korean native chicken (KNC) breeds consisting of Hwanggalsaek Jaeraejong (HJ), Korean Rhode Island Red (KR), Korean White Leghorn (KL), Korean Brown Cornish (KC), and Korean Ogye (KO). We investigated their production performances, vitalities, and stress responses. We measured the survival rate, body weight, age at first egg-laying, hen-day egg production, egg weight, amount of telomeric DNA, heterophil-lymphocyte ratio (H/L ratio), and heat shock protein (HSP)-70, HSP-90α and HSP-90β gene expression levels for 493 KNCs. The survival rate was highest in KR, and lowest in KO. Body weights were steadily high in the order of KC, KR, HJ, KO and KL. Average hen-day egg production was highest in KL, and lowest in KC. While the amount of telomeric DNA was highest in KR, and lowest in KC. Furthermore, both the H/L ratio and the HSP-90β gene expression level were highest in KC, and lowest in KR. These results indicated that the KR breed was highly resistant to stress, whereas KC was more susceptible to stress. Taken together, it is considered that with improvements the KC breed would be more suited to be used as a Korean broiler breed while KL would be more appropriately used as a Korean layer breed. In addition, it is considered that the KR breed is appropriate to be used as a maternal chicken breeder based on good production capacity and excellent robustness, while the HJ breed is desirable to be improved as a high-quality Korean meat breed based on its excellent meat quality.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.345-350
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• 2014

The aim of this study was to investigate the effect of high temperature on the viability of probiotic organisms (Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae) mixed with animal feed under controlled conditions by simulating a farm feed bin in the summer. Following inoculation of probiotics into the feed, the pH and probiotic viability were monitored during an 8-day incubation at room temperature. Sterile and non-sterile feeds displayed different patterns of pH changes, with increased pH in non-sterile feed at 2 days, but a pattern of decreasing pH at 4 days. The viabilities of S. cerevisiae and B. subtilis after mono/co-inoculation were maintained without substantial changes during the incubation, whereas L. plantarum viability tended to decline. In both non-sterile and sterile feeds, the probiotics were maintained or grew without any antagonistic effects. Probiotic viability was also tested upon a shift to high temperature ($60^{\circ}C$). There was no distinct change in pH between sterile and non-sterile feeds after the temperature shift. L. plantarum and S. cerevisiae could not survive at the high temperature, whereas B. subtilis displayed normal growth, and it inhibited the growth of contaminant microbes. Fungal growth was not observed in non-sterile feed 2 days after supplementation with B. subtilis. Therefore, heat resistant B. subtilis could be safely used in feed bins to inhibit microbial contamination, even at high temperatures. The prevention of elevated temperature in feed bins is necessary for the utilization of L. plantarum and S. cerevisiae during the summer season.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.93-100
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• 2014

In general, whey obtained from various cheese batches is being reused, so as to improve the texture and to increase the yield and the nutrient value of the various final milk-based products. In fact, re-usage of whey proteins, including whey cream, is a common and routine procedure. Unfortunately, most bacteriophages can survive heat treatments such as pasteurization. Hence, there is a high risk of an increase in the bacteriophage population during the cheese-making process. Whey samples contaminated with bacteriophages can cause serious problems in the cheese industry. In particular, the process of whey separation frequently leads to aerosol-borne bacteriophages and thus to a contaminated environment in the dairy production plant. In addition, whey proteins and whey cream reused in a cheese matrix can be infected by bacteriophages with thermal resistance. Therefore, to completely abolish the various risks of fermentation failure during re-usage of whey, a whey treatment that effectively decreases the bacteriophage population is urgently needed and indispensable. Hence, the purpose of this review is to introduce various newly developed methods and state-of-the-art technologies for removing bacteriophages from contaminated whey and whey products.

• Journal of Plant Biotechnology
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• v.41 no.1
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• pp.56-63
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• 2014

Using commercial radish varieties for processing, about 30% of radish was discarded due to the root shape and low purity. To raise the processing ability, we tried to develop a new variety producing H-shaped root. As another characteristic required in variety for processing is high purity, we tried to raise purity using simple sequence repeats (SSR) markers for testing seed purity in every segregating generation. To develop Male-sterile (MS) seeding parent, we crossed commercial variety of 'Gwan dong spring' and 'Gyeo ryong spring'. One elite inbred was selected as recurrent parent for the MS plant. The major horticultural traits of selected inbred line were disease resistance, late bolting, heat resistance and bright green root top color. To develop pollen parent, we crossed commercial variety of 'Tae sang king' and 'Seoul spring'. We used individual selection method to develop H-shaped hard root and disease resistant inbred. In each segregating generation, we selected one plant based on phenotype and the uniformity of selected plant was tested by SSR markers using self-pollinated seeds. In the first segregating generation, 64.6% of sib plants shared the same band in PCR amplification using ACMP-490 primer and 66.7% using cnu-316 primer. The uniformity of segregating generations using ACMP-490 and cnu-316 raised in second generation to 68.8%, 70.8%, respectively; in third generation to 93.8%, 100%; in fourth generation to 93.8%, 100%; in fifth generation to 95.8%, 100%; in sixth generation to 100%, 100%. A novel cross was made using selected MS parent and pollen parent. When we checker the horticultural traits using autumn cultivation, the novel cross variety produced H-shaped root comparing other commercial varieties and produced highly uniform radish. Thus we registered this novel cross variety as 'YR ORE' at 2013 (Registration No. 4550).

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.