• The Korean Journal of Mycology
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• v.24 no.2 s.77
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• pp.135-141
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• 1996

Auxotrophs and drug resistant mutants from the mycelia of Lentinus edodes were obtained by UV irradiation at survival rates of $0.024{\sim}2.45%$ and ethidium bromide (EtBr) enrichment after UV irradiation. The mutation rate was 0.40%, and back mutation rate was $4.81{\times}10^{-4}{\sim}8.46{\times}10^{-4}$. Various amino acid-, nucleic acid-, and vitamin-requiring auxotrophs were isolated. The concentrations of several fungicides, antibiotics and amino acid analogues inhibiting the growth of L. edodes were determined. The MIC values for cycloheximide, benomyl, and p-fluorophenylalanine were 2, 2000, and 1000 ug/ml respectively. Five p-fluorophenylalanine-resistant mutants and eight benomyl-resistant mutants were selected by UV irradiation.

• Reproductive and Developmental Biology
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• v.33 no.4
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• pp.189-194
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• 2009

The objective of this study was to determine effects of different culture media. Preantral follicles were mechanically extracted from bovine ovaries and cultured for 16 days in tissue culture medium (TCM)-199, DMEM or alpha-minimal essential medium ($\alpha$-MEM) + 10% FBS + 0.1 mg/ml sodium pyruvate + 100 mIU/ml FSH. The collected primary follicles from ovary were higher than the primary and secondary follicles. The survival rates of the follicles in TCM-199 were significantly higher (p<0.05) than those in DMEM and $\alpha$-MEM. The diameter of the follicles progressively increased during 12 days of culture. The maximum size ($139.1{\pm}5.4\;{\mu}m$) reached on Day 12 of the in vitro culture and decreased on Day 16. These results suggest that in a culture of bovine preantral follicles, TCM-199 is an optimal medium and a longer-term culture of preantral follicles (>12 days) may be needed to form antra.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1723-1729
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• 2018

The aim of this work is to investigate the protective efficacy of emodin, an active, naturally-occurring anthraquinone derivative of several traditional Chinese herbs, against Brucella abortus infection in macrophages. Brucella were incubated with different concentrations of emodin and showed that bacterial survival rates were markedly reduced in a dose-dependent manner at increasing incubation time points. Through bacterial infection assay, the highest non-cytotoxic concentration of emodin demonstrated attenuated invasion of Brucella into macrophages, however it did not inhibit the growth of these pathogens within the host cells. On the other hand, emodin effectively decreased the number of bacteria that adhered to host cells, which indicated its potential as an anti-adhesin agent. Furthermore, using immunoblotting and FACS assay for detecting MAPK signaling proteins and F-actin polymerization, respectively, the results showed that the emodin-incubated cells displayed modest reduction in the phosphorylation levels of ERK1/2 and inhibition of F-actin polymerization as compared to control cells. These findings indicate the potential use of emodin as a naturally-occurring alternative method for the prevention of animal brucellosis although this requires confirmation of safe clinical doses.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.863-870
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• 2010

We investigated geographical condition and soil characteristic of ginseng cultivation site. At all sites, crown density adjusted by 80%. and Air and soil temperature were also measured. The geographical condition vary ato all sites. and soil shows similar characteristics with typical forest soil of Korea. The results shows the Air temperature needs to be higher than $15^{\circ}C$ for seed budding at April When soil temperature reach at 8, leaf of foest ginseng starts to bud. A forest ginseng is influenced by forest type, planting type and budding rates. In the case of a seedling planting, an seeding emergence rate is high, but the rate is decreased rapidly after three years On the other hand, direct seeding shows lower seedling emergence rate, but survival rate is higher than seedling-planting.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.64-68
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• 2002

Eighty methanol extracts prepared from Vietnamese plants were tested for their cytotoxic activity against A549 cells, a human lung carcinoma cell line. Nine extracts showed survival rates of tumor cells of less than 30% at $100\:{\mu}g/mL$ of the methanol extracts. Among them, three were less than 15%; Meliosma pinnata (VK03, 4%), Goniothalamus vietnamensis (VK05, 06, 0%), Garcinia sp. (VK50, 51, 0%) and Aglaia aphanamixis (VK63, 11%). Both leaf and root extracts of Goniothalamus vietnamensis and the leaf extract of a Garcinia species completely inhibited the growth of A549 cells at the concentration of $100\:{\mu}g/mL$ methanol extract.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.85-85
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• 1993

The clinical staging system for laryngeal cancers is not sufficient for prognosticator due to different biologic characteristics and their microenvironment according to primary sites. For determining the prognosticators, the authors peformed immunohistochemical staining to EGFR, p53 protein, and pRB in 40 cases of surgically treated squamous cell carcinomas of larynx in our institute during the past 5 years. The results are as followings; 1. The positive expression rate of p53 protein and negative expression rate of pRB showed correlations with clinical parameters. 2. The three-year survival rate for p53 protein positive cases was worse than the p53 protein negative cases. 3. Expression rate of EGFR was not correlated with the clinical parameters. As a conclusion, expression rates of p53 protein and pRB not only reflect well the biologic behavior of laryngeal cancer, but correlate closely with the tumor factors. Therefore they may be useful as the prognosticator to predict the malignant potency of laryngeal squamous cell carcinomas.

• Journal of Distribution Science
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• v.10 no.3
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• pp.31-42
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• 2012

After the rapidly changing business management environment and financial crisis, high prices and domestic recession in Korea posed threats to the business survival of small and medium enterprises (SMEs). This paper looks at the potential of micro business owners for sustainable development: those who have a spirit of entrepreneurship and the potential to be a hidden champion. Our study of micro business values uses structure equation modeling by LISREL. We have done so in order to understand the foundation of management innovation and success model of micro enterprise by increasing the entrepreneurship and management performance relationship analysis. A micro-enterprise is a type of small business, found only in Korea, often registered as having ten or fewer employees. We examine the successful type of hidden champions and the influence of entrepreneurship on start-ups in business. As compared to past research on the SME entrepreneurship, this study segments small businesses even further. Small business entrepreneurship was classified into three forms that are most appropriate for the Korean situation today: innovation, risk-taking, and pro-activeness. This research is meaningful as it is Korea's first empirical analysis on four business types: wholesale and retail sales, food and lodging business, service business, and manufacturing business. Thus far, research on small business entrepreneurship was carried out using small-scale investigative analysis. However, this research attempted to develop a model that can explain a cause-effect relation of the motivational level when it comes to the difference of entrepreneurship by each business type and small business start-up success factors. Various conceptual and operational definitions could be developed in a diverse and precise manner. Independent variables that are related to the success of small businesses can be developed additionally to examine the success factors related to the systematization in detailed manner. The research showed that the innovation, risk-taking and pro-activeness of the manifested difference in the degree of perception depending on the type of small businesses. Among the four business types, the ones that manifested the highest successful start-up rates were food, service, wholesale and retail sales and manufacturing. Results after conducting the regression analysis are shown on, which proves that the small business entrepreneurship exerts direct effect on the financial management performance of small businesses. In other words, small business entrepreneurship exerts a positive effect on the small business financial success and management performance. The R² value is 0.61. It is possible to know that the perception of systematization and variables on attitude explains the 61% of the success for small self-employed businesses management performance. We define start-up key factors that are helpful to achieve internal growth of firms by finding business survival strategies. The results also focus on Korean government policy for micro enterprise and small business support.

• KSBB Journal
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• v.21 no.2
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• pp.110-117
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• 2006

During routine maintenance, animal cell lines are commonly cryopreserved in growth medium containing serum with 10% DMSO. But, in case of bioprocess under the serum-free conditions, including cultivation of cell lines and producing of pharmaceuticals, the cryopreservation should be executed without serum to prevent a cross-contamination. This experiments were performed to investigate the effects of the serum-free cryopreservation on the CHO cells. To improve the survival rates of the cryopreserved CHO cells in serum-free condition, first, the effects of permeable and non-permeable additives for substitute serum on cell viability were investigated. The combination of 10% DMSO and 0.03 M raffinose in MEM-${\alpha}$ without serum indicated 76% of cell viability. However, it did not reach the survival rates(more than 95%) of the conventional cryopreservation. In the second, to evaluate the cryopreservative ability of the serum-free medium(SFM) we compared viability of the CHO cells cryopreserved in the SFMs(Sigma C5467, C4726, and C1707, JBI SF486 and PF486), the cryoprotectant(Genenmed CAN-1000) and the MEM-${\alpha}$ with serum. All solution contained 10% DMSO. As a result of the comparison, cryopreserved cells in the SFMs showed over 95% of viability and appeared predominant viability better than cryoprotectant CAN-1000. Finally, we assessed the stability of the CHO cells in the long-term cryopreservation(LTC) using SFM. Every three months, the cryopreserved CHO cells were thawed to estimate the cell viability and the recovery rates. Then, real-time RT-PCR analyzed the inserted CHO DHFR gene. All results for the LTC appeared the same stability as the serum containing cryopreservation. In the conclusion, it could be seen that the LTC in the SFM can substitute for serum using methods in the bioprocess proceeded by CHO cells for more than 18 months.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.352-362
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• 2022

Photosynthesis and respiration of seagrasses are mainly controlled by water temperature. In this study, the photosynthetic physiology and respiratory changes of the Asian surfgrass Phyllospadix japonicus, which is mainly distributed on the eastern and southern coasts of Korea, were investigated in response to changing water temperature (5, 10, 15, 20, 25, and 30℃) by conducting mesocosm experiments. Photosynthetic parameters (maximum photosynthetic rate, P_max; compensation irradiance, I_c; and saturation irradiance, I_k) and respiration rate of surfgrass increased with rising water temperature, whereas photosynthetic efficiency (α) was fairly constant among the water temperature conditions. The P_max and I_k dramatically decreased under the highest water temperature condition (30℃), whereas the I_c and respiration rate increased continuously with the increasing water temperature. Ratios of maximum photosynthetic rates to respiration rates (P_max : R) were highest at 5℃ and declined markedly at higher temperatures with the lowest ratio at 30℃. The minimum requirement of H_sat (the daily period of irradiance-saturated photosynthesis) of P. japonicus was 2.5 hours at 5℃ and 10.6 hours at 30℃ for the positive carbon balance. Because longer H_sat was required for the positive carbon balance of P. japonicus under the increased water temperature, the rising water temperature should have negatively affected the growth, distribution, and survival of P. japonicus on the coast of Korea. Since the temperature in the temperate coastal waters is rising gradually due to global warming, the results of this study could provide insights into surfgrass responses to future severe sea warming and light attenuation.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.51-59
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• 2014

In this study, we developed a high frequency watermelon regeneration system using three breeding lines ('B02', 'B05' and 'D04') of watermelon (Citrullus lanatus (thunb.) Matsum. & Nakai) which are differed in their fruits in shape, color of pericarp and flesh. The highest frequency of explants with callus was observed by using explants that consist of cotyledon proximal part end in all breeding lines, and the highest rate of callus induction was obtained on MS medium containing 1.0 mg/L BAP + 0.5 mg/L IAA for 'B02' (94%), 3.0 mg/L BAP for 'B05' (95%), 3.0 mg/L BAP + 0.1 mg/L IAA for 'D04' (90%). The highest shoot regeneration rates from derived callus were obtained on MS medium containing 1.0 mg/L BAP + 0.5 mg/L IAA for 'B05' (94%), and then a 'B02' (81%) with a same culture conditions, and the lowest regeneration was obtained on MS medium containing 1.0 mg/L BAP for 'D04' (56%). Regenerated plants showed the best rates of root formation on MS containing 0.1 mg/L IBA for 'B02' (67%), 0.1 mg/L NAA for 'B05' (87%), 0.5 mg/L IAA for 'D04' (88%). The regenerated plants showed a 100% survival rate in soil condition. The tissue culture and regeneration conditions obtained from this study will be useful for regenerating plants in breeding applications, and will be a useful tool for further genetic transformation studies on watermelons.