• Journal of Life Science
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• v.18 no.1
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• pp.136-142
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• 2008

A recombinant Pichia pastoris carrying double expression cassette of Rhodotorula glutinis epoxide hydrolase(RgEH) gene was developed and used for preparing enantiopure (S)-styrene oxide from racemic mixture of styrene oxide. BglII restriction site of original RgEH gene (pPICZ B/RgEH #2) of previous report was mutated using PCR technique for the construction of double expression cassette containing promoter ($P_{AOX1}$), EH gene and transcription terminator ($TT_{AOX1}$) in pPICZ C vector. Double expression cassette with RgEH was inserted into the chromosomal DNA of P. pastoris. $V_{max}$ ($2.2{\mu}mol\;min^{-1}mg\;dcw^{-1}$) on (R)-styrene oxide of P. pastoris with double expression cassette was about 6-fold higher than that ($0.4{\mu}mol\;min^{-1}mg\;dcw^{-1}$) of P. pastoris with single expression cassette. For the determination of the optimal condition, the effects of detergent and temperature on the enantioselective hydrolytic activity and yield of the enantiomer were investigated. When the reaction was performed at $10^{\circ}C$ for 10 min in the presence of 0.5% Tween 20, enantiopure (S)-styrene oxide with 99.9% ee was obtained as the yield 43.4 % from 20 mM racemic sustrate.

• Journal of Mushroom
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• v.2 no.4
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• pp.207-213
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• 2004

The results of examining characteristics of mycelial growth and culture condition for determining the condition of artificially culturing Fomitopsis pinicola are as follows. 1) Mycelial growth and density of F. pinicola. were the highest in the medium of PIDA(Pine Dextrose Agar;66.3mm/10d) followed by the order of GDA, PDA, CDA, PODA, ODA, YM, MCM, MEA(pH 4.7), CHA, and MEA(pH 4.7). 2) Optimal temperature for the mycelial growth and density of F. pinicola were shown to be $30^{\circ}C$, but the mycelia were dead at $40^{\circ}C$. the mycelial growth and density of KNAC9005 strains was the highest at $30^{\circ}C$(66.3mm/10d) followed by the order of 25, 20, 15, 35, 10, and $5^{\circ}C$. 3) Optimal pH for the mycelial growth and density of $40^{\circ}C$ was revealed to be 6.0(88.4mm/10d). above or below pH 6.0, the mycelial growth and density were shown to be retarded. 4) Optimal carbon, nitrogen and organic acid sources for the spawn growth of $40^{\circ}C$ were maltose(331mg/25ml/15d), peptone(347mg/25ml/15d), and glutamic acid(357mg/25ml/15d), respectively. Optimal level of biotin was 370mg/15d and optimal C/N ratio was 40.

• Applied Biological Chemistry
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• v.30 no.3
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• pp.278-284
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• 1987

As a basic research for inhibition of enzymatic browning of apples during dehydration or processing, polyphenol oxidase was extracted from Fuji apples to investigate heat inactivation, chemical inhibition and other properties. Polyphenol oxidase showed the highest activity at $20^{\circ}C$ and pH 5.5 with catechol as substrate, and the Michaelis constant of 0.14 M under the same condition of substrate and pH. The thermal inactivation followed pseudo first-order kinetics to have activation energy of 23.0 kcal/mol and z value of $19.7^{\circ}C$. As for substrate specificity the polyphenol oxidase showed high affinity toward the o-diphenolic compounds, particularly chlorogenic acid. Neither the m- and p-dihydroxy phenols nor monophenols were attacked. Browning by polyphenol oxidase was completely inhibited at the concentrations of 10mM for potassiummetasulfite and thiourea and 1mM for L-cysteine, ascorbic acid and sodium diethyldithiocarbamate.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.535-545
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• 1999

Crease of Streptococcus salivarius is believed to play a critical role in bacterial ecology and pH homeostasis in the mouth, and consequently affect the pathogenesis of dental caries and periodontal diseases. Expression of the urease gene is greatly enhanced by low p. f. excess of Carbohydrate, and faster growth. It was observed that urease activity of the strains of S. salivarius that exhibited no of low urease activity was not increased even in low pH condition. In this study, it was hypothesized that the urease gene of the strains is absent, defected, or greatly changed by genetic combination. In order to prove this hypothesis, chromosomes were obtained from 28 S. salivarius strains which had been isolated from normal teeth and carious lesions, subjected to polymerase chain reaction (PCR) using primers encoding highly conserved sequence from ureC, and then the obtained PCR products were compared. The results were as follows: 1. After PCR the strains generated either one of 0.54- and 1.3-kbp PCR products, or none. 2. All 16 strains having a higher urease activity(<50${\mu}mol/min/mg$) produced 0.54-kbp PCR products. 3. Twelve strains without urease activity and with a lower urease activity(<50${\mu}mol/min/mg$) yield either one of 0.54 and 1.3-kbp PCR products, or none. 4. The DNA sequence of the 0.54-kbp PCR product (pCAP-0.54) exhibited 95% identity to the ureC of S. salivarus 57.I; 30bp were found to be different, which led to difference of only 2 amino acids in the sequence. 5. The DNA sequence of the 1.3-kbp PCR product(pCAP-1.3) was found to be highly homologous to the aminopeptidase C gene of Streptococcus thermophilus. Overall results indicate that there are considerable variations of the urease genes from S. salivarus strains and the variations may affect the uncolytic activity of the bacteria directly of indirectly.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.3
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• pp.413-418
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• 2014

It has been proved that the union of two linear star-configurations in $\mathbb{P}^2$ of type s and t for either $3{\leq}t{\leq}10$ or $\(\frac{t}{2}\)-1{\leq}s$ with $3{\leq}t$ has maximal Hilbert function. We extend the condition to $\[\frac{1}{2}\(\frac{t}{2}\)\]{\leq}s$, so that it is true for either $3{\leq}t{\leq}10$ or $\[\frac{1}{2}\(\frac{t}{2}\)\]{\leq}s$ with $3{\leq}t$, which extends the result of [6].

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.112-118
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• 2007

The present study was conducted to investigate the attributes of ram sexual behaviour under different social conditions. Six intact rams and eight overiectomized ewes were used in this experiment. Ewes were artificially brought into oestrus. All mating traits were recorded every 10 sec during a 1 h mating session under five social conditions viz., ram exposed to single oestrus ewe, ram exposed to single oestrus ewe and audience ram, ram exposed to multiple oestrus ewes, ram exposed to single oestrus ewe with competitor ram and ram exposed to multiple oestrus ewes with competitor ram. Mean intensity of the mating activities during the 1 h mating session under five social conditions was compared. Either vocalization or leg kicking was found to be the predominant teasing activity under all five conditions. Sniffing differed significantly (p<0.05) between different social conditions. Vocalization, leg kicking, and leg kicking with vocalization did not differ significantly (p<0.05) between different social conditions. Mounts/h in the multiple oestrus ewe condition was higher and differed significantly (p<0.05) from other social conditions. Ejaculations/h for the experimental ram was higher when exposed to multiple oestrus ewes in comparison to other social conditions. Mounts/ejaculation was low in the audience ram condition in comparison to the other four social conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.110-113
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• 1992

$n^{+}$-p homojunction InP diodes were fabricated using thermal diffusion of Sulfur into p-type InP substrates(Zn doped, LEC grown, p=2.3${\times}$10$^{16}$c $m^{-3}$). The Sulfur diffusion was carried out at 550$^{\circ}C$, 600$^{\circ}C$, 700$^{\circ}C$ for 4 hours in a sealed quartz ampule(～2ml in volume) containing 5mg I $n_2$ $S_3$ and Img of red phosphorus. The formed junction depth was below 0.5$\mu\textrm{m}$. After the removal of diffused layer on the rear surface of the wafer, the beak ohmic contacts to the p-side were made with a vacuum evaporation of An-Zn(2%) followed by an annealing at 450$^{\circ}C$ for 5 minutes in flowing Ar gas. The front contacts were made with a vacuum evaporation of Au-Ge(12%) followed by an annealing at 500$^{\circ}C$ for 3 minutes in flowing Ar gas. The remarkable sprctral response of the cells obtained at the region of 6000-8000${\AA}$ region. The open circuit voltage $V_{oc}$ , short circuit current density $J_{sc}$ , fill factor and conversion efficiency η of the fabricated pattern solar cells(diffusion condition : at 700$^{\circ}C$ for 4 hours) were 0.660V, 14.04㎃/$\textrm{cm}^2$, 0.6536 and 10.09%, respectively.y.

• Korean Journal of Microbiology
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• v.16 no.2
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• pp.79-89
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• 1978

The RK-temperate phage which infected with Bacillus cereus was isolated and the characters were investigated. The induction of RK-temperate phage from host bacterium attained by ultraviolet light irradiation (15W, 30cm, 30-120sec) and mitomycin C treatment (0.2-2 ug/ml). The host range of RK-temperate phage was not revealed with lysogenic and related strains of B. cereus. But B. cereus(PS) 352 which obtained by N-nitrosoguanidine treatment(1,000.$\mu$g/ml) to phage infected with host bacteria was sensitive bacteria of RK-temperate phage. RK-temperate phage was stabilized at the condition of nutrient broth (pH 7-8), Tris-buffer (pH 7-8) and ammonium buffer (pH 8-9) and Sorensen's phosphate buffer (pH 6-7), but unstabilized at other salt solutions and pH range. Also, thermostability was to 45.deg.C but unstabilized at above 50.deg.C. At RK-temperate phage, the measurment values of head, neck, mid tail and end tail were 59nm, 9*16nm, 10*189nm, and 10*14nm respectively. The morphology of head was regular polyhedron, and the end tail was coneate form. On the one hand, the number of capsid protein layer of tail were consist of 4, 35, and 1 at neck, mid tail, and end tail, respectively. RK-temperate phage was identified with DNA phage and G+C contents were 38.63. The latent time of RK-temperate phage was 30 minutes and the burst size was 70-80. And the host bacteria was lysed in case of multi-infection, above moi 1.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.600-604
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• 2003

This study pointed at isolation of bunker-C oil degrading bacteria and then estimation of it's degrading capability in environmental conditions. Degradation ratio of the excellent isolate was appeared to 40.5% and 44.7% when the oil was treated to 1% and 5%, respectively. The isolate was identified to Acinetobater calcoaceticus SEBCM. In pH test, high degrading effect was appeared to about 73% at pH 6 and pH 7, and low degrading ratio was 37% at pH 4. Its growth condition at temperature has not large variation in $15^{\circ}C\;{\sim}30^{\circ}C$, Quantity of nitrogen for it's good growth was ranged of $0.5\;g/L{\sim}2\;g/L$. As these results, we realized that this isolate have good activity when treated to $15\;{\sim}30^{\circ}C$ of temperature and $6{\sim}7$ of pH.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1307-1313
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• 2002

This study was performed to investigate the single and combined effect of concentrations of garlic juice according to the pH and temperature on the growth of Salmonella enteritidis in brain heart infusion broth, and to develope Response surface model for the effect of concentrations of garlic extract. The results of electric conductibility of Salmonella enteritidis growing in the range of incubation temperature ($25~42^{\circ}C$), pH (5.5~9.0) and concentration of garlic Juice (0~0.8%) showed that a badge with high temperature had low D.T.value and concentration of garlic extract were significantly correlated with D.T.value (p<0.01). Growth of Salmonella enteritidis in the condition of $37^{\circ}C$ and pH 7.0 presented the lowest D.T.value.