• Journal of Microbiology and Biotechnology
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• 제21권10호
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• pp.1064-1068
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• 2011

The osmotolerant yeast, Candida magnoliae, which was isolated from honeycomb, produces erythritol from sugars such as fructose, glucose, and sucrose. Erythrose reductase in C. magnoliae (CmER) reduces erythrose to erythritol with concomitant oxidation of NAD(P)H. Sequence analysis of the 5'-flanking region of the CmER gene indicated that one putative stress response element (STRE, 5'-AGGGG-3'), found in Saccharomyces cerevisiae, exists 72 nucleotides upstream of the translation initiation codon. An enzyme activity assay and semiquantitative reverse transcription polymerase chain reaction revealed that the expression of CmER is upregulated under osmotic and salt stress conditions caused by a high concentration of sugar, KCl, and NaCl. However, CmER was not affected by osmotic and oxidative stress induced by sorbitol and $H_2O_2$, respectively. The basal transcript level of CmER in the presence of sucrose was higher than that in cells treated with fructose and glucose, indicating that the response of CmER to sugar stress is different from that of GRE3 in S. cerevisiae, which expresses aldose reductase in a sugarindependent manner. It was concluded that regulation of CmER differs from that of other aldose reductases in S. cerevisiae.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.35.1-35.1
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• 2011

수열합성법으로 제작된 ZnO 나노와이어는 저온 MBE (Molecular Beam Epitaxy) 방식과 달리 Ti, Au와 같은 촉매로 부터 성장이 끝난뒤 나노와이어 끝에 남는 촉매를 제거해야할 필요가 없으며, 저온에서 합성이 가능하기 때문에 현재 연구가 많이 되고 있는 방법중에 하나이다. 본 연구에서는 수열 합성법을 이용하여 금속촉매 또는 AZO로 seed를 형성한 후 기판 위에 균일한 크기의 ZnO 나노막대를 성장시키고 성장밀도 및 길이의 간편한 제어를 하였다. 이를 위해 계면활성제인 PEI (Polyethyleneimine) 첨가 및 Chloride ($Cl_-$)를 조절하여 ZnO 나노와어의 성장밀도를 조절 하고자 하였다. 실험방법으로는 전구체인 Zn(NO3)2${\cdot}$6H2O와 HMT에 Chloride 계열인 Ammonium chloride 와 Kcl 의 몰농도를 각각 조절하고 PEI를 첨가하여, ZnO 나노와이어를 성장하였다. 성장된 ZnO 나노와이어의 특성을 평가하기 위해 field emission scanning electron microscopy (FE-SEM)을 이용하여 광학적인 특성을 측정하였으며, 결정성을 조사하기 위해 X-ray diffraction (XRD)을 이용하여 분석하였다. 또한 scanning PL 장비를 통해 photoluminescence양을 측정하고 ZnO 나노와이어의 응용 가능성을 평가하였다.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3437-3442
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• 2011

An on-line flow injection analysis with dual pre-concentration method was developed to determine the ultra trace tri and hexavalent chromium in water. In this system, the cation and anion pre-concentration columns were combined with a 10-port injection valve and then used to separate and concentrate Cr (III) and Cr (VI) selectively. The two species of concentrated chromium were sequentially eluted and determined by using HCl-KCl buffer of pH 1.8 as an eluent. Cr (III) was oxidized by hydrogen peroxide to Cr (VI). It was detected spectrophotometrically at 548 nm by complexation with DPC (diphenylcarbazide). Several factors such as concentration of $H_2O_2$, DPC and coil length in reaction condition were optimized. The linear range for Cr (III) and Cr (VI) was 0.1-50 ${\mu}g$/L. The limit of detections ($3{\sigma}$) of Cr (III) and Cr (VI) were 52 ng/L and 44 ng/L under the optimized FIA system, and their recoveries 98% and 103%, respectively. This method was applied to analyze contamination level of chromium species in tap water, groundwater and bottled water.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.375-379
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• 2002

Methyl mercaptan oxidase was successfully induced in Thiobacillus thioparus TK-m using methyl mercaptan gas, and was purified for the detection of mercaptans. The purification procedure Involved a DEAE (diethylaminoethyl) -Sephacel, or Superose 12, column chromatography with recovery yields of 47.5 and 48.5%, and specific activities of 374 and 1240.8 units/mg-protein, respectively, The molecular weight of the purified methyl mercaptan oxidase was 66.1kDa, as determined by SDS-PAGE. The extract, from gel filtration chromatography oxidizes methyl mercaptan, producing formaldehyde, which can be easily detected by the purpald-coloring method. The optimized temperature for activity was found to be at 55$\^{C}$. This enzyme was inhibited by both NH$_4$Cl and (NH$_4$)$_2$SO$_4$, but was unaffected by either KCl or NaCl at less than 200 mM. With K$_2$SO$_4$, the activity decreased at 20 mM, but recovered at 150 mM. In the presence of methanol, full activity was maintained, but decreased in the presence of glycerin, ethanol and acetone 43, 78 and 75%, respectively.

• 약학회지
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• 제51권5호
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• pp.301-306
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• 2007

Rosiglitazone ($Avandia^{(R)}$) represents a new class of antidiabetic drugs which are $PPAR{\gamma}$ agonists. The present study was undertaken to determine whether the new antidiabetic rosiglitazone influences on the agonist-induced regulation of vascular smooth muscle contraction as an antihypertensive and, if so, to investigate the related mechanism. Endothelium-denuded arterial rings from male Sprague-Dawley rats were used and isometric contractions were recorded using a computerized data acquisition system. Rosiglitazone decreased Rho-kinase activating agonist (NaF or thromboxane $A_2$ mimetic)-induced contraction but not depolarization- or phorbol ester-induced contraction. Surprisingly, it slightly potentiated the latter contraction possibly opening a voltage-dependent calcium channel by its chemical structure on 50 mM KCI- or $1{\mu}M$ phorbol 12,13-dibutyrate-induced vasoconstriction. In conclusion, this study provides the evidence and possible related mechanism concerning the biphasic effect of an antidiabetic rosiglitazone as a possible antihypertensive on the agonistinduced contraction in rat aortic rings regardless of endothelial function.

• 한국미생물·생명공학회지
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• 제13권4호
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• pp.377-382
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• 1985

이속 효모간 원형질체 융합에 의해 새로운 알콜발효 균주를 개발하기 위한 전단계로서, Arthro-bacter luteus에서 얻은 zymolyase 5,000을 세포벽 분해효소로 사용하여 전분분해 효모인 C. tropicalis, E. fibuligera 및 알콜발효 효모인 S. cerevisiae 등의 원형질체 형성조건에 대하여 검토하였다. 원형질체 형성의 최적 pH와 온도는 각각 pH 7.5와 35$^{\circ}C$였다. 또한 원형질체 형성에 대한 2-mercapto-ethanol의 효과는 50mM농도에서 가장 좋았으며 삼투압 안정제로는 0.6M KCl이 적당하였다.

• 대한화학회지
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• 제19권6호
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• pp.428-433
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• 1975

물중에 ppb 정도로 존재하는 구리, 납, 카드뮴 및 아연을 동시에 정량하기 위하여 디티존-클로로포름 抽出法으로 농축하여 短形波폴라로그래피法으로 측정하는 방법을 검토했다.디티존鹽으로 클로로포름層에 추출된 이들 이온을 , 디티존보다 약간 과량의 수은(II)이온을 함유하는 염산으로 역추출한 후 支持電解質로서 염화칼륨을 가하고 순수한 클로로포름으로 두번 씻은 다음 短形波폴라로그램을 기록한다. 이 방법으로 구리, 납 및 카드뮴은 3ppb까지, 아연은 14ppb까지 상대오차 10%이내로 할 수 있었다.

• 대한수의학회지
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• 제45권4호
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• pp.485-493
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• 2005

We studied the effects of trazodone on arterial blood pressure in anesthesized guinea pigs, and on vascular responses in isolated thoracic aorta. Trazodone produced a concentration-dependent relaxation in phenylephrine-precontracted endothelium intact (+E) rings, but not in a KCl-precontracted aortic rings. These relaxant effects of trazodone on +E rings were significantly greater than those on denuded (-E) rings. The trazodone-induced relaxation was suppressed by glibenclamide and tetrabutylammonium, but not by N(G)-nitro-L-arginine (L-NNA), N(omega)-nitro-L-arginine methyl ester (L-NAME), methylene blue (MB), nifedipine, indomethacin, 2-nitro-4-carboxyphenyl-n,n-diphenylcarbamate (NCDC) and clotrimazole. In vivo, infusion of trazodone elicited a significant decrease in arterial blood pressure. Trazodone-induced blood pressure lowering was markedly inhibited by intravenous pretreatment of prazosin but not by pretreatment of saponin, L-NNA, L-NAME, MB, nifedipine, glibenclamide, clotrimazole and NCDC. In addition, trazodone produced an increase in twitch force of isolated papillary muscle and left ventricular pressure of perfused heart. These findings suggest that the endothelium-independent vasorelaxant effect of trazodone may be explained by activation of $Ca^{2+}$-activated and ATP-sensitive $K^+$ channels, and the hypotensive effect of trazodone is not associated with cardiac contraction.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3077-3083
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• 2010

The electrochemical detection of As(III) was investigated on a platinum-iron(III) nanoparticles modified multiwalled carbon nanotube on glassy carbon electrode(nanoPt-Fe(III)/MWCNT/GCE) in 0.1 M $H_2SO_4$. The nanoPt-Fe(III)/MWCNT/GCE was prepared via continuous potential cycling in the range from -0.8 to 0.7 V (vs. Ag/AgCl), in 0.1 M KCl solution containing 0.9 mM $K_2PtCl_6$ and 0.6 mM $FeCl_3$. The Pt nanoparticles and iron oxide were co-electrodeposited into the MWCNT-Nafion composite film on GCE. The resulting electrode was examined by cyclic voltammetry (CV), scanning electron microscopy (SEM), and anodic stripping voltammetry (ASV). For the detection of As(III), the nanoPt-Fe(III)/MWCNT/GCE showed low detection limit of 10 nM (0.75 ppb) and high sensitivity of $4.76\;{\mu}A{\mu}M^{-1}$, while the World Health Organization's guideline value of arsenic for drinking water is 10 ppb. It is worth to note that the electrode presents no interference from copper ion, which is the most serious interfering species in arsenic detection.

• 미생물학회지
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• 제29권1호
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• pp.56-62
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• 1991

Extremely halophilic bacteria isolated from salterns at Mado, Kyunggido, Korea, were identified and investigated on their salt requirements. The results have shown that six strains were identified to be belonged to the genus Halobacterium and three strains identified as the fenus Halococcus. Among them, the optimal NaCl concentration for growth of Halobacterium sp. EH10 was at 4.2M and no growth occurs below 2.0M NaCl. The strain, EH10, is nonmotile and showed acid production from glucose, fructose and maltose while H. salinarum is motile and does not produce acid from any carbohydrates. On the other hand, the strain EH10 does not utilize readily glucose while a number of sugars are readily utilized for growth with acid production by H. saccharovorum. Thus, the isolate, EH10, was classified into the genus Halobacterium and could be a novel species of the genus by its main morphological and physiological features including G+C content. The optimal temperature for growth of the isolate, EH10, was 50.deg.C. But this strain did not grow when NaCl was replaced with KCl.