• 생명과학회지
• /
• 제18권1호
• /
• pp.136-142
• /
• 2008

Rhodotorula glutinis epoxide hydrolase (EH) 유전자를 pPICZ vector에 이중발현 cassette로 재조합하여 발현시킨 재조합균주 Pichia pastoris를 제작하였으며 라세믹 styrene oxide 혼합물로부터 고순도 광학활성 (S)-styrene oxide를 제조하는데 사용하였다. 본 연구에서 사용된 R. glutinis EH 유전자는 전보에서 사용한 pPICZ B/RgEH plasmid DNA를 주형으로 하여 얻었으며 PCR 방법으로 BglII 제한자리를 돌연변이 시키고 AOX1 promoter $(P_{AOX1})$-RgEH 유전자-전사종결서열($TT_{AOX1}$)을 이중으로 가진 이중발현 cassette를 만들어 P. pastoris의 염색체 DNA에 삽입시켰다. 반응온도를 $30^{\circ}C$로 하였을 때, RgEH를 이중발현 cassette로 발현시킨 재조합균주 P. pastoris의 (R)-styrene oxide에 대한 $V_{max}$ 값은 $2.2{\mu}mol\;min^{-1} (mg\;dcw)^{-1}$으로 단일발현 cassette로 발현시킨 P. pastoris의 $0.4{\mu}mol\;min^{-1}(mg\;dcw)^{-1}$에 비하여 6배 향상되었다. 광학순도가 높은 (S)-styrene oxide를 제조하는 최적조건을 찾기 위하여 입체선택적 가수분해 속도 및 수율에 미치는 detergent 및 온도의 효과를 실험하였으며, Tween 20을 0.5% 첨가하고 $10^{\circ}C$로 반응시킨 경우 10분 반응을 통해 99.9% ee 이상의 고순도 (S)-styrene oxide를 43.4% 얻을 수 있었다.

• 한국버섯학회지
• /
• 제2권4호
• /
• pp.207-213
• /
• 2004

소나무잔나비버섯 인공재배를 위한 균사배양적 특성을 조사한 결과는 다음과 같다. 1) 소나무잔나비버섯균의 적정배지는 PIDA(Pine Dextrose Agar)에서 66.3mm/10일로 균사생장과 균사밀도가 가장 좋았으며, 그 다음은 GDA, PDA, CDA, PODA, ODA, YM, MCM, MEA(pH4.7), CHA, MEA(pH4.7) 순이었다. 2) 소나무잔나비버섯의 균사생장과 밀도에 가장 적정한 온도는 $30^{\circ}C$이었으며 $40^{\circ}C$에서는 균사가 사멸하였다. KNAC3005 균주는 $30^{\circ}C$에서 66.3mm/10일로 균사생장과 밀도가 가장 양호하였으며, 온도별로는 25, 20, 15, 35, 10, $5^{\circ}C$ 순으로 균사생장 속도와 밀도가 좋았다. 3) 소나무잔나비버섯의 균사생장과 밀도에 가장 적정한 산도(pH)는 6.0에서 88.4mm/10일이며 그보다 높거나 낮으면 균사생장과 밀도에 저해를 받는다. 4) 소나무잔나비버섯의 균사생장에 적합한 탄소원은 maltose로 331mg/25ml/15일이며, 최적 질소원은 peptone으로 347mg이다. 최적 유기산은 glutamic acid로 357mg이었다. 최적 비타민은 biotin으로 370mg/15days이며 C/N율은 40이 적정하였다.

• Applied Biological Chemistry
• /
• 제30권3호
• /
• pp.278-284
• /
• 1987

사과의 건조, 가공 중의 갈변을 방지하기 위한 기초 조사로서 후지 사과로부터 추출한 crude polyphenol oxidase의 특성과 열에 대한 저항성, 갈변 저해제의 저해 효과 등을 조사하였다. Catechol을 기질로 사용하였을 때 polyphenol oxidase의 최적 pH는 5.5, 최적온도는 $20^{\circ}C$, $K_m$ 값은 0.14M이었고, 열불활성화는 유사일차반응을 보였으며 이때 활성화에너지$(E_a)$와 Z값은 각각 23.0cal/kmol, $19.7^{\circ}C$였다. 기질에 따른 친화력은 o-diphenol, 특히 chlorogenic acid에 대하여 높았고, monophenol과 m-diphenol, p-diphenol에 대해서는 나타나지 않았다. Polyphenol oxidase에 의한 갈변은 thiourea와 potassium metabisulfite는 10mM에서, L-cysteine과 ascorbic acid, sodium diethyldithiocarbamate는 1mM에서 현저하게 저해되었다.

• Restorative Dentistry and Endodontics
• /
• 제24권4호
• /
• pp.535-545
• /
• 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.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권1호
• /
• pp.112-118
• /
• 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.

• 충청수학회지
• /
• 제27권3호
• /
• pp.413-418
• /
• 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].

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
• /
• pp.110-113
• /
• 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.

• 미생물학회지
• /
• 제16권2호
• /
• pp.79-89
• /
• 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
• /
• 한국생물공학회 2003년도 생물공학의 동향(XII)
• /
• pp.600-604
• /
• 2003

벙커 C유 1-5%가 주입되었을 경우에는 40.5%, 44.7%가 제거되었으며 본 유류분해균주는 A. calcoaceticus SEBCM-1로 명명하였다. pH 6과 pH 7에서 분해율이 약 73% 정도로 가장 높게 나타났으며 pH 4에서는 약 37% 정도가 미생물 분해에 의해 저감되는 것으로 나타났다. 본균은 다양한 pH조건에서도 생육이 가능하며 일정 수준의 분해력을 가지는 것으로 확인되었다. 본균은 비교적 넓은 온도 범위에서 왕성한 성장이 가능하며 분해가 가능할 것으로 판단된다. 본균의 영양분 조성 중 질소원의 주입량은 $0.5\;g/L{\sim}2\;g/L$ 범위에서 미생물 성장이 활발하였으며 0.1 g/L와 4 g/L로 주입했을 경우에는 미생물 성장이 크게 저하되는 것으로 관찰되었다.

• 한국환경과학회지
• /
• 제11권12호
• /
• pp.1307-1313
• /
• 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.