• Journal of Environmental Science International
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• v.5 no.2
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• pp.179-185
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• 1996

This study was conducted to investigate the effects of environmental factors such as temperature, salinity, pH, and UV light on-the survival of life-threatening Vibrio vulnificus. In the temperature range of 15 to $25^{\circ}C$, the numbers of V. vulnificus incieased during the 6-day incubation, but outside this range, the survival of V. vulnificus was poor. Incubation between 1 and $10^{\circ}C$ showed that V. vulnifcts survived poorly below $10^{\circ}C$. At sal:nities between 5 and 25ppt, the numbers of V. vulnificus increased or remained unchanged for 6-day. At salinities above this range, the numbers of V. vulnificus decreased. The optimal pH range was 6.5 to 8.0 and outside this range, the survival ratio of V. vulnificus was small. At 15-and $25^{\circ}C$, UV radiation was bactericidal for cultures of V, vulnificus. The counts of V. vulnificus were reduced approximately 10, 000-fold after 2h of UV light treatment at both temperatures. Above results mowed 1ha't environmental factors were effective on the survival of V. vulniucus in the environment.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.215-223
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• 2003

This study was to investigate the effects of fertilization time and culture medium of pig oocytes matured in-vitro by liquid boar sperm. The sperm rich fraction (30∼60 ml) was slowly cooled to room temperature (20∼23$^{\circ}C$) by 2 h after collection. Semen was transferred into 15 ml tubes, centrifuged at room temperature for 10 min 800 ${\times}$ g, and the supernatant solution was poured off. The concentrated sperm was resuspended with 5 ml of the LEN diluent to provide 1.0${\times}$10$^{9}$ sperm/ml at room temperature. The resuspended semen was cooled in a refrigerator to 4$^{\circ}C$. The medium used for oocyte maturation was TCM-199 supplemented with 26.19 mM sodium bicarbonate, 0.9 mM sodium pyruvate, 10 $\mu\textrm{g}$/ml insulin, 2 $\mu\textrm{g}$/ml vitamin B$_{12}$ , 25 mM HEPES, 10 $\mu\textrm{g}$/ml bovine apotransferrin, 150 $\mu$M cysteamine, 10 IU/ml PMSG, 10 IU/ml hCG, 10 ng/ml EGF, 0.4% BSA, 75 $\mu\textrm{g}$/ml sodium penicillin G, 50 $\mu\textrm{g}$/ml streptomycin sulfate and 10% pFF. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at 38.5$^{\circ}C$, 5% $CO_2$ in air. Oocytes were inseminated with liquid boar sperm stored at 4$^{\circ}C$ for 2 days after collection. Oocytes were coincubated for 1, 3, 6 and 9 h in 500 ${mu}ell$ mTBM fertilization media with 1.0${\times}$10$^{6}$ sperm/ml concentration, respectively. Thereafter, oocytes were transferred into 500 ${mu}ell$ NCSU-23, HEPES buffered NCSU-23, PZM-3 and PZM-4 culture media, respectively, for further culture of 6, 48 and 144 h. The rates of sperm penetration and male pronuclear formation were higher in the fertilization times for 6 and 9 h than in those for 1 and 3 h. The rates of cleaved oocytes were higher in the fertilization times for 6 and 9 h (85.0 and 84.6%) than in those for 1 and 3 h (61.1 and 76.8%). The percentage of blastocyst formation from the cleaved oocytes was highest in the fertilization time for 6 h (33.6%) than in that for 1, 3 and 9 h (11.4, 23.0 and 29.6%). Mean cell numbers per blastocyst were 32.9, 27.6, 26.3 and 24.4 in the fertilization times for 6, 9, 3 and 1 h, respectively. The rate of blastocyst from the cleaved oocytes and the number of cells per blastocyst were higher in HEPES buffered NCSU-23 culture medium than in NCSU-23, PZM-3 and PZM-4 culture media. In conclusion, we found out that liquid boar sperm stored at 4$^{\circ}C$ could be used for in-vitro fertilization of pig oocytes matured in-vitro. Also, we recommend the coincubation time of 6 h in 500 ${mu}ell$ TBM fertilization medium with 1${\times}$10$^{6}$ sperm/ml concentration and the HEPES buffered NCSU-23 culture medium for in-vitro fertilization of pig oocytes matured in-vitro.

• KSBB Journal
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• v.14 no.2
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• pp.174-180
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• 1999

An actinomycetes strain No.4 which produce the cholesterol oxidase(EC 1.1.3.6), was isolated from soil and identified as Streptomyces sp. based on taxonomic studies. The conditions of cholesterol oxidase production and enzymatic properties were investigated. The optimum composition of medium for production of the enzyme was 1% soluble starch, 2% corn steep liquor, 0.1% $KH_2PO_4$, 0.1% $NaNO_3$ and 0.05% $MgSO_4$ (pH 7.0). The optimum pH and temperature of the cholesterol oxidase were pH 6.0~7.5 and $37^{\circ}C$, respectively. The enzyme was stable in the range of pH 6.0~9.0. The isoelectric point determined by multichambered electrofocusing unit was in the range of pH 6.0~6.5.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.1025-1031
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• 2011

Autoignition characteristic is an important parameter for designing diesel or PCCI engines. In particular, diesel spray flames are lifted from the nozzle and the initial flame is formed by an autoignition phenomenon. The lifted nature of diesel spray flames influences soot formation, since air will be entrained into the spray core by the entrainment of air between the nozzle region and the lifted flame base. The objective of the present study was to identify the effect of heat loss on the ignition delay time by adopting a coflow jet as a model problem. Methane ($CH_4$), ethylene ($C_2H_4$), ethane ($C_2H_6$), propene ($C_3H_6$), propane ($C_3H_8$), and normal butane (n-$C_4H_{10}$) fuels were injected into high temperature air, and the liftoff height was measured experimentally. As the result, a correlation was determined between the liftoff height of the autoignited lifted flame and the ignition delay time considering the heat loss to the atmosphere.

• Journal of Embryo Transfer
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• v.13 no.2
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• pp.159-172
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• 1998

사람 성장호르몬 수용체(hGHR) cDNA는 PCR방법에 의하여 fagment로서 보고되어진 바 있으나, liver cDNA로 부터 전장을 cloning한 보고는 없는 실정으로 본 연구에서는 기능을 가진 약 4.6kbp의 cDNA hGHR을 cloning 하는데 성공하였다. 먼저 cloning하기 위하여 human liver mRNA와 human breast cancer tissue로부터 회수한 mRNA를 RT-PCR방법에 의하여 human cDNA library와 cloning에 필요한 probe를 제작하였다. human library mRNA는 GT-PCR방법에 의하여 증폭하여 증폭되어진 산물은 λZAP Vector를 이용하여 cDNA library를 구축하였고,screeing을 위하여 임 보고 되어진 hGHR fragment native sequence를 기초로 N-terminal부분의 primer를 설계하여 950bp의 probe를 얻는데 성공하였다. 이 probe를 이용하여 준비된 human liver cDNA library로부터 2.5$\times$10 6개의 plaque로부터 6개의 positive clone을 획득하였고, 이들중 poly Asignal인 "AATAAA"를 포함하고 있는 가장 긴 약 3.8kbp의 clone을 sequencing한 결과 open reading frame을 포함하고 있었으나, 5'부분의 결손되어 있었다. 그리하여 이 부분은 human breast cancer tissue로 부터 회수한 mRNA를 RT-PCR에 의하여 증폭하였고, sequencing결과 이미 보고되어진 native hGHR와 비교한 결과 하나의 nucleotide가 silent mutation으로 판명되었다.한편 human liver cDNA library로부터 cloning한 3.8cp의 positive clone의 5'end의 결손된 부분에 silent mutation된 PCR 산물을 연결함으로써 native hGHR와 유사한 cDNA hGHR subcloning에 성공하였다. 이러한 cDNA hGHR의 clone이 function을 가지고 있는지를 검토하기 위하여 eukaryotic 발현 vector인 pCXN2에 의거 ligation한 후 chinese hamster ovary cell[CHO-KI]에 transfect를 실시하였다. Dexamethasone은 첨가하지 않고 hGH만의 존재하에서 이들 cell을 배양시키고 cell menbrane에서 발현 여부를 판정키 위하여 hGHR monocloual antibody를 사용하여 flow cytometery해석을 실시하는 한편 125I-hGH binding assay에 의하여 hGH binding activity를 측정하였다. 최종적으로 GH signal transduction의 target genedf으로 알려져 있는 serine protease inhibitor 2.1(Spi 2.1) gene의 promotor activity를 검토한 결과 hGHR을 transfect한 CHO Cell에 있어서 hGH의 농도에 의존적으로 증가되었다. 따라서 본 실험에서 cloning한 cDNA hGHR는 native hGHR와 같은 기능을 가지는 것으로 판명되었다.것으로 판명되었다.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1285-1290
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• 2000

The objective of this study was to evaluate the characteristics on the thermal denaturation of free drip released from pork loin during chilled storage using DSC (differential scanning calorimetry) with pH, concentration of NaCl and phosphate. The increasing of pH stabilized the heat resistance of the proteins in drip. A $T_1$ greatly increased of $T_{max}$ by $6.33^{\circ}C$ incline from pH 5.5 to 6.5. And increasing the concentration of NaCl destabilized the heat resistance of drip. $T_1$ showed the greatest reduction of $T_{max}\;(9.41^{\circ}C)$ in the presence of 5% NaCl. The presence of STPP (Sodium Tripolyphosphate) enchanced the thermal stability of pork drip by $5.84^{\circ}C$ in the presence of 0.5% STPP. As temperature increased from 40 to $100^{\circ}C$, lightness $(L^*)$ increased from 41.1 to 69.5, while redness $(a^*)$ decreased from 26.70 to 5.40. Particularly, both values of $L^*-$ and $a^*-$ greatly changed by 78% from 40 to $60^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.221-224
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• 2002

Nucleophilic addition reactions of benzylamines (BA; $XC_6H_4CH_2NH_2$) to ethyl-${\alpha}$-cyanocinnamates (ECC;$YC_6H_4CH$=C(CN)COOEt) have been investigated in acetonitrile at $30.0^{\circ}C$. The rate is first order with respect to BA and ECC. The rate is slower than that expected from the additive effect of ${\sigma}^-$ or $R^-$ for the activating groups (CN and COOEt). Natural. bond orbital ${\pi}^{\ast}_{c=c}$ calculations show that the contribution of COOEt group may not be fully effective despite the coplanar molecular structure. The selectivity parameters including the cross-interaction constant (${\rho}_{xy}$ = -0.22) indicate that the addition occurs in a single step. The kinetic isotope effects ($k_H/k_D$=2.5-2.8) involving deuterated BA ($XC_6H_4CH_2ND_2$) nucleophiles and activation parameters (${\Delta}H^{\neq}=4{\sim}6\;kcal\;mol^{-1};{\Delta}S^{\neq}=-45{\sim}-52\;e.u.$) suggest a cyclic transition state in which N-$C_{\alpha}$ and H-$C_{\beta}$ bonds are formed concurrently.

• Journal of the Korean Chemical Society
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• v.38 no.10
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• pp.749-752
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• 1994

Two furanosesquiterpenes, (5'E)-5-(2',6'-dimethylocta-5',7'-dienyl) furan-3-carboxylic acid (1) and (1'E,5'E)-5-(2',6'-dimethylocta-l',5',7'-trienyl) furan-3-carboxylic acid (2), were isolated from soft coral Sinularia lochmodes collected from Palikir pass at Pohnpei Micronesia, June, 1990 in Hawaii. Their structures were elucidated by $^1H$, $^{13}C$ NMR, Homo-COSY, $^1H$-$^{13}C$ (1 bond) Heteronuclear Multiple Quantum Coherence Spectroscopy (HMQC), $^1H$-$^{13}C$ (2 and 3 bond) Heteronuclear Multiple Bond Coherence Spectroscopy (HMBC), Electron Impact Mass Spectroscopy (EI-ms), and Infrared Spectroscopy (IR).

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.44-48
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• 1990

Alkalophilic sp. YC-335 isolated from soil was capable of producing large amount of cyclodextrin glycosyltransferase (CGTase) in culture broth. This enzyme was successively purified 52.9 folds with 17.8 yield by ethanol precipitation, DEAE-Toyopearl column chromatography and Sephadex G-100 column chromatography. The purified enzyme have a molecular weight of approximately 75,000 estimated by SDS polyaerylamide gel electrophoresis. The optimum pH and temperature for the enzyme activity were 6.0 and 5$0^{\circ}C$, respectively. The enzyme stable between pH 6 and 10, and up to 5$0^{\circ}C$. The thermostability of the enzyme was increased up to 6$0^{\circ}C$ by the addition of 15mM CaCl$_2$.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.164-168
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• 2001

Rice black-streaked dwarf virus (RBSDV) and Maize rough dwarf virus (MRDV) are closely related viruses. Since the two viruses produce identical symptoms on maize, barley, and wheat, diagnosis of infected plants is difficult. Previously, we reported that partial cDNA clones of RBSDV S5 and S6 from the Japanese isolate (RBSDV-H) have lower sequence homology to MRDV than do cDNA clones from other genomic segments. In order to test whether cDNA clones of RBSDV-H S5 and S6 can be used for molecular diagnosis, RBSDV field isolates from Korea and from Hokkaido, Japan were tested in dot blot hybridizations probed with RBSDV-H S5 and S6 cDNA colnes. Hybridization with these probes was more intense against the RBSDV genome than against the MRDV genome. Therefore, RBSDV-H S5 and S6 cDNA clones can be used to differentiate between the two viruses. Furthermore, RBSDV-H S5 and S6 clones reacted more strongly against the viruses from stunted maize plants from Korean fields than to MRDV, indicating that RBSDV may be the causal disease agent in maize plants in Korea.