• Korean Journal of Veterinary Service
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• v.44 no.3
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• pp.149-155
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• 2021

In virucidal efficacy testing, the chemical inactivation cannot be determined for all viruses due to the difficulties or the inability to culture sufficiently or the risk of exposure to the viruses. Therefore, disinfectants against these viruses could be evaluated by different methods and surrogate viruses are used as alternative. In this study we developed a method for efficacy testing of veterinary disinfectants using one of the candidate surrogate viruses, bacteriophage MS2, as part of the research on the selection of surrogate viruses for efficiency of efficacy testing of veterinary disinfectants. This method is based on the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Bacteriophage and disinfectant are reacted in suspension in accordance with the APQA guidelines and then a newly established double agar layer method is applied for the efficacy test. The double agar layer method is summarized as follows: 1) The bottom agar with 1.5% agar is boiled and cooled before poured into petri dishes at volume of 20 mL, and dried under biological safety cabinet. 2) The top agar with 0.7% agar is boiled and kept at 50℃ before E. coli culture was seeded. 3) The serially diluted bacteriophage MS2-disinfectant mixtures 0.05 mL and E. coli host 0.01 mL (OD₆₀₀ 0.2~0.3) are mixed with 5 mL of top agar and incubate them at 50℃ for 5 min for reaction. 4) The resulting mixture is poured over top of a bottom agar plate and rocked sufficiently to ensure that the top agar covers the entire surface of the bottom agar. 5) The double agar layer is then placed under biological safety cabinet to allow the agar layer to solidify and subsequently incubated at 37℃ for 24 hr. 6) Following incubation, the plates may be inspected for plaques and record results.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.539-549
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• 2024

This study employed text mining techniques like frequency analysis, word clouds, and LDA topic modeling to assess consumer satisfaction and dissatisfaction with Hyundai Motor Company in the Chinese market, compared to brands such as Toyota, Volkswagen, Buick, and Geely. Focusing on compact vehicles from these brands between 2021 and 2023, this study analyzed customer reviews. The results indicated Hyundai Avante's positive factors, including a long wheelbase. However, it also highlighted dissatisfaction aspects like Manipulate, engine performance, trunk space, chassis and suspension, safety features, quantity and brand of audio speakers, music membership service, separation band, screen reflection, CarLife, and map services. Addressing these issues could significantly enhance Hyundai's competitiveness in the Chinese market. Previous studies mainly focused on literature research and surveys, which only revealed consumer perceptions limited to the variables set by the researchers. This study, through text mining and comparing various car brands, aims to gain a deeper understanding of market trends and consumer preferences, providing useful information for marketing strategies of Hyundai and other brands in the Chinese market.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.60-66
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• 1994

This study was conducted to determine the optimum conditions of inducing callus, proliferating callus, forming somatic embryos, and regenerating plantlets via somatic embryogenesis, for the purpose of producing artificial seeds and substantially developing plant factory technologies that can be employed to all seasons production of Bupleurum plants. Callus was efficiently induced from leaf tissues at three leaf stage in the MS medium supplemented with 2, 4-D 2mg /1 and thidiazuron(TDZ) 0.lmg /1. Callus induction from leaf tissues at maturity was mostly effective in the mixture of 2,4- D 2mg /1 and TDZ 1.0mg /1 while that from flower bud tissues was fairly good in the MS medium containing 2,4-D 1 or 2mg /1.Callus was formed in 15 to 20 days after culture initiation in the MS media supplemented with 2, 4- D 1-2mg /1 and TDZ 0.l-1.0mg /1. Such hormones as kinetin 3mg /1, GA 1mg /1, and the mixture of GA 1mg /1 and TDZ 1mg /1 effected markedly to proliferate the callus cells.The optimum temperature and light intensity for callus culture were found to be $25^{\circ}C$ and 3000 Lux, respectively. Direct plant regeneration from cultured callus was fairly made on hormone-free MS or half-strength MS medium. Somatic embryogenesis was most frequently observed in hormone-free media:60 somatic embryos per 20ml in MS medium and 28 somatic embryos per 20ml in half -strength MS medium. There were three stages-globular, heart, and torpedo-in development of somatic embryos, among which globular stage was more frequently observed in MS medium rather than in half-strength MS medium. Somatic embryos induced from suspension culture fairly differentiated a number of shoots and roots on hormone-free and half-strength MS solid medium.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.167-176
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• 1997

This study was carried out to evaluate the potential for preselection of transgenic embryos prior to transfer into recipient animals. In these experiments, I used a 3.2 kb transgene which contained the neomycin resistance gene (neo) and lac Z gene driven by the $\beta$ actin promoter (iacZ Ineo). Oocytes were aspirated from abattoir ovaries, matured in TCM-199 supplemented with 10% fetal bovine serum (FBS), 5 ${\mu}\textrm{g}$/ml LH, 0.5 ${\mu}\textrm{g}$/ml FSH, 100 unit/ml penicillin, and 100 ${\mu}\textrm{g}$/ml streptomycin for 22 to 24 hrs then inseminated with a sperm suspension of 1 X 10$^6$ sperm/ml containing 5 ${\mu}\textrm{g}$/ml of heparin. At 18-20 hrs after insemination, cumulus cells were removed by vortexing and pronuclei of centrifuged zygotes microinjected with the lacZ/neo construct (3 ng/$\mu$l). All cultures were carried out in CR1aa with transfected BRL monolayers containing 3 mg/ml BSA, 20 $\mu$/ml NEM amino acids and 40 $\mu$I/ml BME amino acids. To identify the appropriate concentration of G418 for selection, non-microinjected zygotes were cultured in the presence of 0, 50, 100 and 200 $\mu$g/ml of G418. After 8 days of culture in these treatments, 44/145 (30.3%), 13/150 (8. 7%), 1/151 (0.7%) and 0/134 (0.0%) devel-oped to the blastocyst stage in 0, 50, 100 and 200 $\mu$g/ml of G418, respectively. A total of 1,127 zygotes were microinjected and placed into culture (without G418) and subsequently 710 (63.0%) cleaved. At 48 hrs post-injection, embryos ($\geq$2-cell) were randomly assigned to control (medium alone) or G418 (100 ${\mu}\textrm{g}$/ml) treatments. A control culture of 740 non-microinjected embryos from the same replicates of embryos were also placed into control medium. After 8 days in culture, 54/343 (15.7%) and 22/367 (6.0 %) of the microinjected embryos developed to the blastocyst stage in control and G418 media, respectively. A total of 151/740 (27.2%) of the non-microinjected embryos placed in the control medium developed to the blastocyst stage. The blastocysts in the control treatment had a mean of 70.7 ${\pm}$ 4.7 cells of which 23.1 ${\pm}$ 2.6 (32.7%) stained for $\beta$-Gal activity. B1astocysts in the G418 treatment had a mean of 48.8${\pm}$7.5 cells of which 40.3 ${\pm}$ 4.1 (82.6%) stained for $\beta$-Gal ac tivity (P<0.05). In the control treatment 26 of 30 (87.0%) blastocysts had some cells with $\beta$-Gal activity while all of the blastocysts in the G418 treatment had some cell with $\beta$-Gal ac tivity (P<0.05). However, ICM colonies in either control or G418 treatments were not expressed any epiblast cell except of trophetoderm celIs. The $\beta$-actin promoter/lacZ gene may not be e expression or silence expression in epiblast cells These results clearly show an enrichment of blastocysts expressing the transgene in the majority of their cells after culture in the presence of G418. The exogeneous gene was not express a and silence in ICM colonies especiallly epiblast cells except of trophectederm cells. Even though the higher rate cell number expressed of exogeneous gene in the G418 treatments, a total cell number was decrease significantly (P<0.05) of which might be also drop of the establishment of ES like-cell colonies and production of transgenic animals. However, futher studies need to determine the viability of these selected embryos and the avability of production of transgenic offspring.

• KSBB Journal
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• v.21 no.4
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• pp.248-254
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• 2006

Animal cell culture industry has a large market and an exponential growth rate among biological industry field. Chines hamster ovary(CHO) cells are the most widely used cell lines for recombinant protein production. They can avoid infection from polio, herpes, hepatitis B, HIV, measles, adenovirus and etc. Moreover it is easy to transfection recombinant genes and possible to suspension culture. Serum free media is one of the most important factor of protein production. Because serum has problems. Serum is not defined the contents until now, it has a number of proteins, lipids, carbohydrates and unknown molecules that cause of risk involve in infection and high cost of product purification. CHO cell line cultured using serum free media were the basis of a very successful method to produce(glyco-)protein in mammalian cells, which are then used as pharmaceutical products. Also, the low protein content of the developed medium facilitates downstream processing and product purification. But non-adapted CHO cells have a limit of proliferation cultured using serum free media and it takes very long time to adapt non-adapted cells to serum free media. There are a number of causes of a limit of proliferation using serum free media. Absence of growth factors and growth stimulating molecules is a major factor of the reasons. It makes growth signals and moves cell cycle. And increase of cellular stress is another reason. It induces increase of intraceullar ROS concentration. The purpose of this study is about improvement of proliferation capacity of non-adapted CHO cells cultured using serum free media without adaptation process.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.158-165
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• 1999

Purpose : To investigate the percentage of colonies wi1h16or more cells distribution of human skin fibroblast according to in vitro aging, and to evaluate the relationship between percentage of colonies with 10 or more cells and in vivo donor age in human skin fibroblast culture. Material and Method : C1, C2, C3a, and C3b human skin fibroblast samples from three breast cancer patients were used as subjects. The C1, C2, and C3a donor were 44, 54, and 55 years old, respectively. C3a and C3b cells were isolated from the same person. Single cell suspension of skin fibroblasts was prepared with primary explant technique. One hundred cells are plated into 100m1 tissue culture flask and cultured for two weeks. The colony size was defined as colonies with 16 or more cells. The cultured cell was stained with crystal violet, and number of cells in each colony was determined with stereo microscope at $\times$10 magnification. Passage number of C1, C2, C3a and C3b skin fibroblast were 12th, 17th, and 14th, respectively. Results : Percentage of colonies with 16 or more cells of skin fibroblast samples decreased with increasing in vitro passage number. In contrast, cumulative population doublings of skin fibroblast sample increased with increasing in vitro passage number. Percentage of colonies with 16 or more cells also decreased with increasing population doublings in human skin fibroblast culture. There was strong correlation with percentage of colonies with 16 or more cells and population doublings En C3a skin fibroblast sampie. At the same point of population doublings, the percentage of colonies with 16 or more cells of the young C1 donor was higher level than the old C3a donor. Conclusion : The population doublings increased with increasing in vitro passage number but percentage of colonies with 16 or more cells decreased. The results of this study imply that percentage of colonies with 16 or more cell is useful as a indicator of in vitro human skin fibroblast aging and may estimate the in vivo donor age.

• Journal of Life Science
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• v.22 no.4
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• pp.508-515
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• 2012

In this study, DEAE-cotton [derivatized by 2-(diethylamino)ethyl chloride hydrochloride (DEAE HCl)] was prepared as a carrier for immobilized $Pichia$ $stipitis$ for ethanol production. When cotton was derivatized with 0.5 M DEAE HCl, the yeast cell suspension was adsorbed at 100% of the initial cell $OD_{600}$. The adsorbed yeast cells were estimated to be 101.8 mg-dry cells/g-DEAE-cotton. In particular, when a flask culture using the immobilized yeast cells was conducted in a glucose and xylose-containing medium, the yeast cells on the DEAE-cotton gradually produced ethanol, according to glucose and xylose consumption; the ethanol yield was approximately 0.33 g-ethanol/g-monosaccharide. Because DEAE-cotton was successfully used as a carrier for ethanol production from a glucose and xylose-containing medium, we expect that this bioethanol production process may be used for the bioethanol production process from the hydrolysate of lignocellulosic biomass. All the results of DEAE-cotton were compared with those of DEAE-cellulose as a carrier for immobilization.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.272-281
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• 1985

The ginseng extract was investigated for their effects on the fermentation of Kluyveromyces fragilis IFO 0288, and the addition of 0-5.0% of ginseng extract from skim milk media were compared to its effects during suspension culture at $30^{\circ}$ for 168 hours. The results are summarized as follows; 1. The addition of 1.0% and 5.0% ginseng extract were significantly increased pH and acidity compared to control. 2. $CO_2$ evolution was significantly in 1.0% but inhibited in 5.0% ginseng extract 3. Alcohol production was more producted and shortened of fermentation time in 1.0-5.0% than 0-0.5% added groups. 4. The number and growth rates of yeast was shortened inductive phase and lengthened extinctive phase in 1.0-5.0% added groups. 5. Free sugar contained in ginseng extract was not significantly affected by fermentation of yeasts.

• Restorative Dentistry and Endodontics
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• v.42 no.4
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• pp.316-323
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• 2017

Objectives: This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems. Materials and Methods: Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of Enterococcus faecalis, randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU). Results: The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups (p < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria. Conclusions: All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.

• Korean Journal of Animal Reproduction
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• v.14 no.1
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• pp.1-8
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• 1990

These experiments were carried out to investigate the effects of cumulus cells for in vitro fertilization and development of bovine follicular oocytes matured in vitro. The bovine ovaries were obtained at a slaughter house and the follicular oocytes surrounded by cumulus cells were collected by puncturing follicles with 2~6 mm of diameter. Bovine oocytes were matured in vitro for 24~26 hours in a CO2 incubator with 5% CO2 in air at 39$^{\circ}C$. The medium used for maturation was TCM-199 supplemented with hormones, pyruvate, FCS and antibiotics. Epididymal spermatozoa were capacitated by in vitro culture for 2~3 hours in BO solution containing BSA(5mg/ml) and caffeine(2.5mM). Insemination was made by introducing about 10~15 matured oocytes into the suspension of capacitated spermatozoa. Six hour after insemination the eggs were transferred to TCM-199 supplemented with FCS(10%) and HEPES(25mM), cultured for 7~8 days with 10~15 eggs/well in 4-well multidishes(Nunc Co.) forming cumulus cell monolayer. The results obtained in these experiments were summarized as follows ; 1. The majority of the follicular oocytes with compacted cumulus cells existed in GV stage while those with dispersed or denuded cumulus cells existed GVBD and M II stage. 2. After 24~26 hours maturation, the maturation rates of the follicular oocytes cultured in TCM-199 containing hormones were slightly higher than those of oocytes cultured in medium without hormones, and the frequency of cumulus compacted or denuded oocytes reaching M II stage cultured in medium containing hormones was 75.7% or 51.7%, respectively(P<0.05). 3. After 20 hours in vitro insemination, percentages of ova fertilized were 61.4% or 51.4%, respectively, for cumulus oophorus intacted or removed, and increased frequency of ova with both male and female pronuclei was found when cumuli were present(P<0.05). 4. The rates of embryos developed to 2-, 4-, 8-, 16-cell and morula or blastocyst stage after cocultured with cumulus cells were 65.0%, 45.3%, 34.7%, 28.0% and 22.7%, respectively. The results for momla or blastocyst stage were significantly higher than those of the embryos cultured in the basic medium(P<0.05).