• Korean Journal of Poultry Science
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• v.16 no.1
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• pp.1-8
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• 1989

This experiment was conducted to improve the performance of chickens by the precise separation and analysis of chromosomes which are integrated genetic materials, and by the use of gene manipulation techniques. Following are the main results obtained. 1. When the chromosomes were separated through the leucocyte culture and analyzed by Giemsa banding techniques (especially by the method in which 20 layers of banding patterns could be found in chromosome ＃1), the normal Patterns of chromosomes ＃l-9 and sex chromosomes, and the location of constitutive heterochromatin without any gene activities in all chromosomes were discovered. 2. To utilize the primodial germ cells (PGC) as the genetic vector which is one of the most important gene manipulation techniques, PGC's from triploid were transplanted to normal host embryos. Since the donor PGC's(3n) were found in the gonads of growing host embryos gene manipulation in poultry using PGC's, seemed to be possible.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.281-291
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• 1999

The objective of this study was to optimize the freezing/thawing method of in vitro produced Hanwoo blastocysts. Day 7 blastocysts after IVF were vitrified using EFS40 (40% ethylene glycol, 18% ficoll, 0.3 M sucrose and 10% FBS added m-DPBS) as a freezing solution and electron microscope (EM) grid (V-G) or straw (V-S) as an embryo container. In both method, freezing/thawing were treated by 2-step, treatment time was required in V-G method and V-S method, for 2 min / 3 min and 3.5 min / 10 min, respectively. Embryo survival was assessed as re-expanded and hatched rates at 24 h and 48 h after warming, respectively. The results obtained in these experiments were summarized as follows: when the effect of exposure in vitrification solution and chilling injury from freezing procedure on in vitro produced expanded blastocysts were examined, at 24 h after warming, embryo survival in exposure group (100.0%) was not different compared to that in control group (100.0%), although those results were significantly different with two vitrified groups (V-G: 87.8, V-S: 77.8%) (P＜0.001). However, at 48 h after warming, hatched rates of V-G group (67.8%) were significantly higher than those of V-S group (53.3%) (P＜0.05). In addition, this hatched rate in V-G group was not different with that in exposure group (73.3%). When the effects of embryo developmental stage (early, expanded and early hatching blastocysts) and embryo container (EM grid and straw) to the in vitro survival of vitrified-warmed day 7 Hanwoo blastocysts were simultaneously examined, fast developed embryos were indicated the better resistance to freezing than delayed developed one, irrespective of embryo containers (early; 57.1 ＆ 24.4%, expanded; 84.7 ＆ 60.6%, early hatching; 91.7 ＆ 80.0%) (P＜0.001). Especially, in expanded and early hatching blastocysts, embryo survival of V-G group (67.8, 95.0%) was significantly higher than those of V-S group (53.0, 65.0%) at 48 h post warming, respectively (P＜0.05, P＜0.001). Therefore, this study indicates that Hanwoo blastocysts can be cryopreserved more simple, efficient and successful by vitrification method using EM grid.

• Journal of Life Science
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• v.8 no.5
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• pp.604-613
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• 1998

The last enzyme of the sesquiterpen phytoalexin capsidiol synthesis in tobacco cell, 5-epi-aristolochene hydro-xylase which convert 5-epi-aristolochene (EAS) to capsidiol, was cloned by a reverse transcription polymerase chain reaction strategy and cDNA library screening. Cloned CYP-B3 contained high probability amino acid matches to known plant cytochrome P450 sequences and open reading frame with the conserved FxxGxRxCxG heme-binding region. Transcripts of CYP-B3 were not detected in control cells, but induced in elicitor-treated cells. Furthermore, CYP-B3 transcripts were induced by fungal extracts and cellulase but not by other stimuli(chilling, heat shock and 2,4-D). Induction of CYP-B3 transcripts by elicitor treatment was not affected by ancymidol and ketoconazole treat-ments suggesting that an inhibition of hydroxylase activity by Cyt P450 inhibitors resulting from post translational processing event.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.19-24
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• 1978

The differences in Vibrio parahaemolyticus detection ratio were compared between the isolation methods, the Most Probable Number technique and single dilution tube method. During the period from February to October in 1976, 298 samples of sea water, 112 of bottom deposit, 169 of shellfish, and 80 of fish samples collected along the south coastal area of Korea were examined to determine the detection ratio of Vibrio parahaemolyticus. It was often observed that Vibrio parahaemolyticus was detected in higher diluted samples even through negative in lower dilution. Three hundred and forty three samples out of 659 samples submitted to the test by MPN procedure appeared positive for Vibrio parahaemolyticus showing $52\%$ detection ratio. Whereas only 149 samples, corresponding $22.5\%$, were positive for Vibrio parahaemolyticus in the lowest dilution grade. The positive result was $24.5\%$ in the lowest dilution grade and $50\%$ by MPN Procedure in sea water samples, $28.6\%$ and $65.2\%$ in bottom deposit, $22.5\%$ and $56.2\%$ in shellfish and $7.5\%$ and $32.5\%$ fish samples. When tested by triplicate tubes, $61.7\%$ of 149 Vibrio parahaemolyticus positive samples appeared positive in one tube, $28.9\%$ of them were positive in two tubes and $9.4\%$ of them were positive in all three tubes. The detection ratio determined by MPN procedure was more than two times higher than that of single dilution in triplicate tubes.

• Journal of Life Science
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• v.29 no.12
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• pp.1408-1414
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• 2019

Enzymes are widely used in industrial applications such as detergents, food, feed production, pharmaceuticals and medical applications and major contributors to clean industrial products and processes. To screen, identify, and characterize the enzymes the zymography techniques are routinely used. The zymography technique is a simple, sensitive, and quantifiable technique that is widely used to detect functional enzymes following electrophoretic separation in sodium dodecyl sulfate (SDS)-polyacrylamide gels. The method is a versatile two-stage technique involving protein separation by electrophoresis followed by the detection of enzyme activity in polyacrylamide gels under non-reducing conditions. It is based on SDS-polyacrylamide gel (PAG) copolymerization with substrates, which are degraded by the hydrolytic enzymes restored in enzyme reaction buffer after the electrophoretic separation. Any kind of biological sample can be applied and analyzed on zymography, including culture supernatants of microbes, plants extracts, blood, tissue culture fluids, enzymes in foods extracts and metaproteome. The advantage of zymography is that it is possible to directly detect the protein with activity on the electrophoretic gel as well as confirm the activity at the nanogram level. Thus, this zymography technology can be applied in various fields. However, these advantages are rather disadvantageous and can often lead to experimental errors. In this review, the advantages, disadvantages, and problem solving of zymography technique are described.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.106-111
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• 2012

Purpose: The purpose of this study was to compare the effect of 3 chairside polishing methods and laboratory polishing methods on surface roughness and $C.$ $albicans$ adhesion of polyamide denture base. Materials and methods: Using contact profilometer, the surface of polyamide specimens ($25{\times}15{\times}2mm$) was studied after conventional polishing without finishing and after chiarside polishing with 2 chiarside polishing kits and chairside-pumice polishing following finishing with tungsten carbide bur. To evaluate the adhesion of $C.$ $albicans$, $C.$ $albicans$ suspension was overlayed on the test specimen. And the specimens were incubated for 2 hours. Imprint culture method was achieved and counted the colony on the agar plate. Polished polyamide were evaluated using a scanning electron microscope. The statistics were conducted using one-way ANOVA and in case of difference, Scheffe test and Tamhane's T2 test were used. Results: Surface roughness (Ra) of surfaces polished with 2 chairside polishing kits had higher than conventional polishing and pumice polishing. The highest roughness value was $0.32{\pm}0.10{\mu}m$, and the lowest was $0.02{\pm}0.00{\mu}m$. The adhesion of $C.$ $albicans$ on the specimens polished with chairside polishing group and pumice polishing group were increased than conventional polishing group ($P$<.01). Conclusion: Conventional laboratory polishing was found to produce the smoothest surface and the lowest adhesion of $C.$ $albicans$. Two groups polished with Chairside polishing kits were similar with respect to surface roughness. Surface of the specimen polished with pumice is significantly smoother than 2 chairside polishing groups, but the result of $C.$ $albicans$ adhesion is that group polished with pumice was similar with 2 chairside polishing groups ($P$>.01).

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.424-431
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• 2017

This study was conducted to set the optimum nutrient solution concentration by growth stage for new strawberry cultivars 'Berrystar' and 'Jukhyang'(Fragaria ${\times}$ ananassa Duch. cvs. 'Berrystar', 'Jukhyang') grown through hydroponics to improve the quality and yield. Three different EC levels were applied to the nutrient solution. The treatment levels were 0.7, 1.0 and 1.3 times higher than the nutrient concentration standard for 'Seolhyang' based on the 'Manual for strawberry cultivation' of Rural Development Administration. Based on the results, there were no significant differences in growth of 'Berrystar' by EC level. 'Jukhyang' showed the most vigorous growth grown in 1.3 times higher nutrient concentration. While the growth of 'Berrystar' and 'Jukhyang' grown in higher EC level has leaves with more chlorophyll concentration. However the quantum yield of leaves was not affected by the treatments. On the treatment with 1.3 times higher EC level, the weight, length, width and firmness of 'Berrystar' and 'Jukhyang' were significantly high. The sugar contents of the harvest analyzed by HPLC did not differed particularly, but the percentage composition of reducing sugar and non-reducing sugar were presented differently depending on the treatments. Marketable fruit yield increased as nutrient concentration increases. However, there were no large differences by treatments. Meanwhile, 'Jukhyang' showed significant difference by nutrient concentration and had the largest yield for a treatment grown in 1.3 times higher EC level. Based on these results, it is recommended to provide the same nutrient solution concentration level to the nutrient concentration standard of 'Seolhyang' for 'Berrystar', and the 1.3 times higher level for 'Jukhyang'.

• Parasites, Hosts and Diseases
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• v.27 no.2
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• pp.87-100
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• 1989

Eimeria tenella, an intracellular protozoan parasite infecting the epithelial cells of the ceca of chickens, causes severe diarrhea and bleeding that can lead its host to death. It is of interest that 2. tenezla first penetrate into the mucosal intraepithelial Iymphocytes (IEL) before they parasitize crypt or villous epithelial cells. This in vitro study was undertaken to know whether the penetration of E. tenella into such a lymphoid cell is a beneficial step for the parasite survival and development. Three sequential experiments were performed. First, the in vitro established bovine kidney cell line, MDBK cells, were evaluated for use as host cells for E. tenella, through morphological observation. Second, the degree of parasite development and multiplication in MDBK cells was quantitatively assayed using radioisotope labelled uracil ($^3H-uracil$) . Third, the E. tenella sporozoites viability was assayed after preincubation of them with thicken spleen cells. E. tenella oocysts obtained from the ceca of the infected chickens were used for the source of the sporozoites. Spleen cells (I) obtained from normal chickens (FP strain) were preincubated with the sporozoites (T) at the E:T ratio of 100:1, 50:1 or 25:1 for 4 or 12 hours, and then the mixture was inoculated into the MDBK cell monolayer. Morphologically the infected MDBK cells revealed active schisogonic cycle of E. tenella in 3~4 days, which was characterized by the appearance of trophozoites, and immature and mature schizonts containing merogoites. The 3H-uracil uptake by E. tenella increased gradually in the MDBK cells, which made a plateau after 48~60 hours, and decreased thereafter. The uptake amount of $^3H-uracil$ depended not only upon the inoculum sixte of the sporozoites but also on the degree of time delay (preincubation; sporozoites only) from excystation to inoculation into MDBK cells. The 3H-uracil uptake became lower as the preincubation time was prolonged. In comparison, after preincubation of sporozoites with spleen cells for 4 or 12 hours, the 3H-uracil uptake was significantly increased compared with that of control group. From the results, it was inferred that, although the penetration of E. tenella sporozoites into the lymphoid cells such as IEL is not an essential step, it should be at least a beneficial one for the survival and development of sporozoites in the chicken intestine.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.56-62
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• 2003

To investigate the entrapping behavior of blue crab, rock shell and green ling, which are mainly caught with the other trap nets in the coastal area of Yellow Sea, by the using duration of trap nets through the water tank experiment. We select the three kinds of trap nets which have different using duration such as new, 6 months and 12 months used one, and observe the entrapping ratio into the trap nets, respectively. In the mean while, in order to obtain the basic data for the estimate of mesh selectivity of the other trap nets, the entrapping behavior into the trap nets for green ling which has high activity compared to blue crab and rock shell, are examined to the three kinds of mesh size (35mm, 50mm and 65mm). The results are as follows ; 1. The mean entrapping ratio of blue crab by the using duration of trap nets in high with 4.4 fishes (44.0%) in the 6 months used one, become lower with 2.9 fishes (28.0%) in the new one, and with 2.0 fishes (20.0%) in the 12 months used one. 2. The mean entrapping ratio of rock shell by the using duration of trap nets in high with 7.3 fishes (36.7%) in the new one, and become lower with 7.2 fishes (35.8%) in the 6 months used one, and with 5.7 fishes (28.3%) in the 12 months used one. 3. The mean entrapping ratio of green ling by the using duration of trap nets in high with 3.4 fishes (34.0%) in the 6 months used one, and become lower with 3.0 fishes (30.0%) in the new one, and with 2.8 fishes (28.0%) in the 12 months used one. 4. The mean residual ratio of green ling by the mesh size of trap nets is high with 2.4 fishes (24.0%) in the 35mm mesh size, and become lower with 2.2 fishes (22.0%) in the 50mm mesh size and 2.0 fishes (20.0%) in the 65mm mesh size.

• Journal of Life Science
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• v.31 no.7
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• pp.609-616
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• 2021

Bacterial soft rot, caused by Pectobacterium carotovorum subsp. carotovorum (Pcc), is one of the destructive diseases of radish (Raphanus sativus) in Asian countries. The objective of this study was to establish an efficient bioassay method for the evaluation of bacterial soft rot resistance in commercial radish cultivars. First, an efficient bioassay method for examining resistance to bacterial soft rot in commercial radish cultivars was investigated. Six commercial radish cultivars were tested under various conditions: two temperatures (25℃ and 30℃), three inoculations methods (drenching, spraying, and root dipping), and two growth stages (two- and four-leaf stages). The results suggested that spraying with 1×10⁶ cfu/ml of bacterial inoculums during the four-leaf stage and incubating at 30℃ could be the most efficient screening method for bacterial soft rot resistance in commercial radish cultivars. Second, we investigated the degree of resistance of 41 commercial radish cultivars to five Pcc isolates, namely KACC 10225, KACC 10343, KACC 10421, KACC 10458, and KACC 13953. KACC 10421 had the strongest susceptibility in terms of moderately resistant disease response to bacterial soft rot. Out of the 41 radish cultivars, 13 were moderately resistant to this pathogen, whereas 28 were susceptible. The moderately resistant radish cultivars in this investigation could serve as resistance donors in the breeding of soft rot resistance or could be used to determine varietal improvement for direct use by breeders, scientists, farmers, researchers, and end customers.