• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.34-41
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• 1994

This experiment was carried out to select the $Sorghum{\times}Sudangrass$ hybrid of high productivity suited for soiling, and growth characteristics and productivity of 9 cultivars of introduced $Sorghum{\times}Sudangrass$ hybrids have been evaluated at the experimental forage field, College of Natural Science of Kon-Kuk university in Chungju over three years. The results obtained are summarized as follows : 1. NC855, Sordan79 and T. E haygrazer were taller than the other varieties as range from 209cm to 213cm. while Supergrazer was the shortest type as 173cm. Among the nine varieties used, NC855 and Pioneer 988 were classified as early maturing varieties, but G83F, FP5 and Supergrazer were classified as lately maturing varieties. 2. The stem diameter of Supergnzer and Sordan79 were thicker than the other varieties, while NC855, Garst757 and FP5 were thin. 3. The tillers of $Sorghum{\times}Sudangrass$ hybrids were ranged from 3.1 to 4.0 and NC855 and FP5 had 4.0 tillers per plant. The dead stubble of Sordan79 was the lowest as 4.0 percentage, while Supergrazer was the highest as 9.8 percentage(P<0.05). 4. GW9110G and T. E haygrazer were susceptible to lodging(P

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1133-1140
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• 2006

Human HtrA1 (High temperature requirement protein A1) is a homologue of the E. coli periplasmic serine protease HtrA. A recent study has demonstrated that HtrA1 is a serine protease involved in processing of insulin like growth factor binding protein (ICFBP), indicating that it serves as an important regulator of IGF activity. Additionally, several lines of evidence suggest a striking correlation between proteolytic activity of HtrA1 serine protease and the pathogenesis of several diseases; however, physiological roles of HtrA1 remain to be elucidated. We used the pGEX bacterial expression system to develop a simple and rapid method for purifying HtrA1, and the recombinant HtrA1 protein was utilized to investigate the optimal conditions in executing its proteolytic activity. The proteolytically active HtrA1 was purified to approximately 85% purity, although the yield of the recombinant HtrA1 protein was slightly low $460{\mu}g$ for 1 liter E. coli culture). Using in vitro endoproteolytic cleavage assay, we identified that the HtrA1 serine protease activity was dependent on the enzyme concentration and the incubation time and that the best reaction temperature was $42^{\circ}C$ instead of $37^{\circ}C$. We arbitrary defined one unit of proteolytic activity of the HtrA1 serine protease as 200nM of HtrA1 that cleaves half of $5{\mu}M\;of\;{\beta}-casein$ during 3 hr incubation at $37^{\circ}C$. Our study provides a method for generating useful reagents to investigate the molecular mechanisms by which HtrA1 serine protease activity contributes in regulating its physiological function and to identify natural substrates of HtrA1.

• Journal of Life Science
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• v.22 no.9
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• pp.1152-1158
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• 2012

Development of transgenic plant increasing crop yield or disease resistance is good way to solve the world food shortage. However, the persistence of marker genes in crops leads to serious public concerns about the safety of transgenic crops. In the present paper, we developed marker-free transgenic rice inserted high molecular-weight glutenin subunit (HMW-GS) gene ($D{\times}5$) from the Korean wheat cultivar 'Jokyeong' using Agrobacterium-mediated co-transformation method. Two expression cassettes comprised of separate DNA fragments containing only the $D{\times}5$ and hygromycin resistance (HPTII) genes were introduced separately into Agrobacterium tumefaciens EHA105 strain for co-infection. Each EHA105 strain harboring $D{\times}5$ or HPTII was infected into rice calli at a 3: 1 ratio of EHA105 with $D{\times}5$ gene and EHA105 with HPTII gene expressing cassette. Then, among 66 hygromycin-resistant transformants, we obtained two transgenic lines inserted with both the $D{\times}5$ and HPTII genes into the rice genome. We reconfirmed integration of the $D{\times}5$ and HPTII genes into the rice genome by Southern blot analysis. Wheat $D{\times}5$ transcripts in $T_1$ rice seeds were examined with semi-quantitative RT-PCR. Finally, the marker-free plants containing only the $D{\times}5$ gene were successfully screened at the $T_1$ generation. These results show that a co-infection system with two expression cassettes could be an efficient strategy to generate marker-free transgenic rice plants.

• Journal of Life Science
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• v.19 no.7
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• pp.994-1002
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• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.

• Journal of Life Science
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• v.20 no.5
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• pp.750-759
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• 2010

The bioactive materials (phenolic compounds, flavonoids, minerals, decursin and decursinol angelate) and biological activities (DPPH [$\alpha,\alpha$'-diphenyl-$\beta$-picrylhydrazyl] free radical scavenging capability, reducing power, and tyrosinase activity) in the extracts of leaf, stem mixture (AGLS), and root (AGR) from Angelica gigas Nakai were examined by using water, hot water and ethanol solvent. The highest extract yield (21.89%) was found in the water extract of AGR. The highest concentrations of phenolic compounds and flavonoids in the ethanol extracts of AGLS and AGR were 14.99% and 14.79%. Major minerals of AGLS and AGR were K, Mg, Fe, Na and Ca. Decursin and decursinol angelate were the major ingredients of Angelica gigas, detected at 18.71 and 18.89 min of retention time by HPLC analysis, respectively. The highest concentrations of decursin and decursinol angelate in the Angelica gigas ethanol extract were found in root ($41.7\;{\mu}g/g$) and leaf ($34.04\;{\mu}g/g$). The highest free radical scavenging activity was found in the hot water extracts of AGLS and AGR, and its activity was stronger in all extracts of AGLS than AGR. The highest reducing power was found in the ethanol extracts of AGLS and AGR and this was dependent on the sample concentration. The hot water extracts of AGLS and AGR revealed the highest inhibition activity on tyrosinase. Overall, these results may provide the basic data needed to understand the biological activities of bioactive materials derived from Angelica gigas.

• Education of Primary School Mathematics
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• v.16 no.2
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• pp.123-145
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• 2013

This study was expected to yield the meaningful conclusions from the experimental group who took lessons based on inductive activities using GeoGebra at the beginning of proof learning and the comparison one who took traditional expository lessons based on deductive activities. The purpose of this study is to give some helpful suggestions for teaching proof to mathematically gifted elementary students. To attain the purpose, two research questions are established as follows. 1. Is there a significant difference in proof abilities between the experimental group who took inductive lessons using GeoGebra and comparison one who took traditional expository lessons? 2. Is there a significant difference in proof attitudes between the experimental group who took inductive lessons using GeoGebra and comparison one who took traditional expository lessons? To solve the above two research questions, they were divided into two groups, an experimental group of 10 students and a comparison group of 10 students, considering the results of gift and aptitude test, and the computer literacy among 20 elementary students that took lessons at some education institute for the gifted students located in K province after being selected in the mathematics. Special lesson based on the researcher's own lesson plan was treated to the experimental group while explanation-centered class based on the usual 8th grader's textbook was put into the comparison one. Four kinds of tests were used such as previous proof ability test, previous proof attitude test, subsequent proof ability test, and subsequent proof attitude test. One questionnaire survey was used only for experimental group. In the case of attitude toward proof test, the score of questions was calculated by 5-point Likert scale, and in the case of proof ability test was calculated by proper rating standard. The analysis of materials were performed with t-test using the SPSS V.18 statistical program. The following results have been drawn. First, experimental group who took proof lessons of inductive activities using GeoGebra as precedent activity before proving had better achievement in proof ability than the comparison group who took traditional proof lessons. Second, experimental group who took proof lessons of inductive activities using GeoGebra as precedent activity before proving had better achievement in the belief and attitude toward proof than the comparison group who took traditional proof lessons. Third, the survey about 'the effect of inductive activities using GeoGebra on the proof' shows that 100% of the students said that the activities were helpful for proof learning and that 60% of the reasons were 'because GeoGebra can help verify processes visually'. That means it gives positive effects on proof learning that students research constant character and make proposition by themselves justifying assumption and conclusion by changing figures through the function of estimation and drag in investigative software GeoGebra. In conclusion, this study may provide helpful suggestions in improving geometry education, through leading students to learn positive and active proof, connecting the learning processes such as induction based on activity using GeoGebra, simple deduction from induction(i.e. creating a proposition to distinguish between assumptions and conclusions), and formal deduction(i.e. proving).

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.357-365
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• 2016

The effects of elevated atmospheric $CO_2$ on photosynthesis and growth of Chinese cabbage (Brassica campestris subsp. napus var. pekinensis) were investigated to predict productivity in highland cropping in an environment where $CO_2$ levels are increasing. Vegetative growth, based on fresh weight of the aerial part, and leaf characteristics (number, area, length, and width) of Chinese cabbage grown for 5 weeks, increased significantly under elevated $CO_2$ ($800{\mu}mol{\cdot}mol^{-1}$) compared to ambient $CO_2$ ($400{\mu}mol{\cdot}mol^{-1}$). The photosynthetic rate (A), stomatal conductance ($g_s$), and water use efficiency (WUE) increased, although the transpiration rate (E) decreased, under elevated atmospheric $CO_2$. The photosynthetic light-response parameters, the maximum photosynthetic rate ($A_{max}$) and apparent quantum yield (${\varphi}$), were higher at elevated $CO_2$ than at ambient $CO_2$, while the light compensation point ($Q_{comp}$) was lower at elevated $CO_2$. In particular, the maximum photosynthetic rate ($A_{max}$) was higher at elevated $CO_2$ by 2.2-fold than at ambient $CO_2$. However, the photosynthetic $CO_2$-response parameters such as light respiration rate ($R_p$), maximum Rubisco carboxylation efficiency ($V_{cmax}$), and $CO_2$ compensation point (CCP) were less responsive to elevated $CO_2$ relative to the light-response parameters. The photochemical efficiency parameters ($F_v/F_m$, $F_v/F_o$) of PSII were not significantly affected by elevated $CO_2$, suggesting that elevated atmospheric $CO_2$ will not reduce the photosynthetic efficiency of Chinese cabbage in highland cropping. The optimal temperature for photosynthesis shifted significantly by about $2^{\circ}C$ under elevated $CO_2$. Above the optimal temperature, the photosynthetic rate (A) decreased and the dark respiration rate ($R_d$) increased as the temperature increased. These findings indicate that future increases in $CO_2$ will favor the growth of Chinese cabbage on highland cropping, and its productivity will increase due to the increase in photosynthetic affinity for light rather than $CO_2$.

• Journal of Preventive Medicine and Public Health
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• v.9 no.1
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• pp.129-138
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• 1976

The causes and problems underlying deaths in perinatal period are often similar and might be expected to yield to same type of preventive measures. This is one of the reasons for attempting to develop a reporting of perinatal mortality and its related matters. This study aims at figuring out the biologic risk factors onto the perinatal death. Considering stillbirth and early neonatal mortality separately, considerable associations between stillbirth and reproductive history of women, are observed, ana it is found that prematurity is the the far most important factor in the early neonatal mortality.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.181-186
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• 1996

This experiment was conducted at National Yeongnam Agricultural Experiment Station in 1995 to identify effects of early flooding in dry seeded rice on rice growth and weed occurrence. The early flooding of emergence date and the 2-leaf stage were not differed significantly on seedling stand, seedling growth of rice and plant characteristics associated with lodging compared to flooding of the 4-leaf stage. However, weed occurrence resulted in 39-61% suppression. Most predominant weed regardless of flooding times was Echinochloa crus-galli, followed by Aneilema japonicum. The Aneilema japonicum, in general, was higher occurrence with earlier flooding, while dry land weeds such as Digitaria sanguinalis, Stellaria alsine etc. reduced. Grain yield of early flooding at emergence date and the 2-leaf stage was higher by 2-5% than that of the 4-leaf stage due to better grain filling ratio and heavier 1,000 grain weight.

• Korean Journal of Medicinal Crop Science
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• v.16 no.4
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• pp.255-260
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• 2008

This study was performed to investigate the enhancement of UV-protection activities and skin-whitening effects from Angelica gigas Nakai extracts on ultra high pressure extraction process. Extraction at $60^{\circ}C$ treated by ultra high pressure for 15 minute and associated with ultrasofication (HPE15) was showed more than double yield, compare conventional extraction, as 12.24% (w/w) from A. gigas. Extracts of HPE15 reduced expression of MMP-1 on UV-irradiated CCD-986sk cells as 122.2% and revealed high inhibitory potency on tyrosinase as 69.4% by adding samples. Extracts of HPE15 from A. gigas showed strong inhibition effect on melanin production test by Clone M-3 cells as 82.4% by adding extracts. From the preliminary observations, we considered that the extracts from A. gigas could be potent natural materials for skin-whitening agent, and could be used as a potential anti-aging agent for the photo-damaged skin.