• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.850-856
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• 2001

This study investigates the ozonation kinetics of 2-chlorophenol in wastewater under acidic condition. Intermediates and by-products generated during the process were rigorously identified and quantified. The major by-products are four carboxylic acids: tartaric acid, oxalic acid, maleic acid, and hydroxymalonic acid. The generation of these organic acids is in agreement with theoretical predictions. But hydroxylated compounds are more favorable to produce than their corresponding non-hydroxylated ones. Based on the information concerning the generation of organic acids and other aromatic intermediates, the complete reaction pathways toward mineralization can be proposed and mathematically modeled. The fitted second-order rate constants are in the same order of magnitude with the results from other studies. Using these oxidation pathways and the corresponding kinetic model, by-products generated in ozonation process can be predicted. This can help in optimizing the design and operation of any subsequent treatment processes.

• 미생물학회지
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• 제49권1호
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• pp.1-7
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• 2013

유전자 재조합체는 상동염색체간의 예정된 DNA 가닥 전이와 교환이 이루어지는 상동염색체 재조합 과정에 의하여 생성된다. 이 재조합 경로는 DNA 이중 가닥 절단(double-strand breaks, DSBs)에 의해서 개시되며, 전이 과정의 중간단계에서 DNA의 구조적 변이 중간체인 단일 가닥 침투(single-end invasions, SEIs)와 이중 홀리데이 접합(double-Holliday junctions, dHJs)이 형성되어 교차성(crossover, CO) 혹은 비교차성(non-crossover, NCO) 결과물이 만들어진다. 본 연구는 이중 가닥 절단, 단일 가닥 침투, 이중 홀리데이 접합과 같은 재조합 중간체와 재조합 결과물의 구조분석에 초점을 두고, 이를 출아효모에서 인위적으로 이중 가닥 절단을 발생시킬 수 있는 HIS4LEU2 "hot spot" 을 이용한 물리적 분석방법으로 감수분열 재조합 중간체를 규명하였다. 물리적 분석을 위하여 동조화 된 세포에 감수분열을 유도한 후 hot spot 자리를 인식하는 제한효소를 처리하면, 재조합 중간체를 형성하고 있는 DNA 단편들을 Southern 분석법을 통해 탐지 및 정량 할 수 있다. 본 연구는 이 시스템으로 감수분열에서 이중가닥 절단으로부터 기인하는 단일 가닥 침투, 이중 홀리데이 접합 그리고 교차성/비교차성 재조합체로 전이되는 DNA의 구조 다형을 분석할 수 있음을 제시한다.

• Journal of Applied Biological Chemistry
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• 제58권1호
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• pp.9-11
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• 2015

Tissue extracts were prepared from liquid-cultured Arabidopsis and reacted with UDP-[$^3H$]-GlcNAc. Phospholipid fractions were then extracted by butanol partitioning. Consecutive thin-layer chromatography identified two glycolipids sensitive to PI-specific phospholipase C, known as early intermediates in glycosylphosphatidylinositol anchor biosynthesis; phosphatidylinositol N-acetylglucosamine and phosphatidylinositol glucosamine.

• Archives of Pharmacal Research
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• 제20권3호
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• pp.288-290
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• 1997

An efficient synthesis of 3-(E)-hydroxy- and 3-(E)-acetoxypropenylcephem derivatives, key intermediates for the synthesis of 3-(E)-propenylcephalosporins was achieved via Stille coupling reaction of 3-trifloxycephem with 3-(E)-tributylstannylallylic alcohol.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2809-2811
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• 2009

• Bulletin of the Korean Chemical Society
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• 제17권5호
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• pp.437-442
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• 1996

Electrocyclic ring-closure of 6-vinylcyclohepta-1,3,5-isocyanate has been carried out in the presence of triphenylphosphine to examine a catalyzing effect of the triphenylphosphine. The preparation of 10-(1-carboalkoxyalkyl)-2,7-methanoaza[10]annulenes by the electrocyclic ring-closure of ketenimine intermediates, which are formed by the reaction of triphenylalkylidenephosphorane and 6-vinylcyclo-hepta-1,3,5-isocyanate, is described. 10-Alkyl-2,7-methanoaza[10]annulenes were prepared by basic hydrolysis of the carboalkoxyaza[10]annulenes and decarboxylation of the acid intermediates. In the same manner, 10-(N-alkyl(or aryl))-2,7-methanoaza[10]annulenes were prepared from the reaction of the isocyanate and N-alkyl(or aryl)iminotriphenylphosphorane via electrocylic ring-closure of carbodiimide intermediate.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.526-528
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• 1992

1-Aminothiohydantoin derivatives were prepared in good yields by the reaction of alkyl or arylisothiocyanates with ethyl hydrazinoacetate hydrochloride in presence of triethylamine. The intermediates, N-amino-N-ethoxycarbonylmethyl-N'-aralkylthioure as, which were formed during the reaction and could be transformed into the appropriate 1-aminothiohydantoins, were isolated and characterized.

• Journal of Photoscience
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• 제9권2호
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• pp.126-129
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• 2002

The chromophore/protein interactions in the photocycle intermediates of photoactive yel- low protein (PYP) were probed by site-directed mutagenesis. The absorption spectra of L- intermediates produced from E46Q, T50V, and R52Q mutants were calculated using the absorption spectra of dark states and difference absorption spectra between L-intermediates and dark states, and compared with that of PYP$\_$L/. The absorption spectrum of R52Q$\_$L/ agreed with that of PYP$\_$L/, but those of E46Q$\_$L/ and T50V$\_$L/ were red-shifted. The effect of these mutations on the absorption spectrum for L-intermediate was comparable to that for the dark state, suggesting that the interaction around the phe-nolic oxygen of the chromophore is conserved in PYP$\_$L/ unlike the crystal structure. On the other hand, we have reported that the absorption spectra of Y 42F$\_$M/, T50V $\_$M/, and R52Q$\_$M/ agreed with that of PYP$\_$M/, but that of E46Q$\_$M/ was red-shifted, suggesting that the hydrogen bond of the chromophore with Glu46 is conserved but that with Tyr42 is broken in PYP$\_$M/. These results suggest that the chromophore inter-acts with Glu46 throughout the photocycle, but never directly interacts with Arg52. This model con- flicts with some of the structural model of PYP intermediates proposed based on the high-resolution X -ray crystallography.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1639-1645
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• 2002

The purpose of this study was to investigate the effects of aflatoxin $B_1$ ($AFB_1$) on the ultracellular morphology alteration, apoptosis induction and reactive nitrogen and oxygen intermediates production of peritoneal macrophages (DPM) from mule ducks. The ducklings were purchased from a commercial hatchery, and were fed a corn-soybean based diet. As the ducklings were grown up to 3 wk of age, the Sephadex-elicited peritoneal exudative cells (PEC) were used as the source for duck peritoneal macrophages. The ultracellular morphology study showed that significant number of cells shifted from category I (normal cell with ruffled membrane) and II (cell membrane blebbing) to category III (cell membrane blebbing and even rupture) after DPM were incubated with $AFB_1$ ($20{\mu}g/ml$) for 12 to 48 h. When DPM were exposed to $AFB_1$ in vitro, the production of NO, $H_2O_2$ and $O_2{^-}$ in macrophages was reduced after 12-48 h incubation with previous LPS stimulation. There was a DNA laddering pattern observed in DPM incubated with $AFB_1$ 5, 10, 20, 50 or $100{\mu}g/ml$ for 12 h. Evidence also revealed that the percentage of apoptotic cells was increased along with the elevation of $AFB_1$ concentration. The results suggest that $AFB_1$ exposure causes duck macrophages going on apoptotic pathway through evidence of ultracellular morphology alteration and DNA laddering in agarose electrophoresis. The production of reactive nitrogen and oxygen intermediates of duck macrophages also depressed after $AFB_1$ exposure, and this implied that $AFB_1$ could cause deteriorated functions of bacteriocidal and tumoricidal activity in duck macrophages.

• 한국식품영양과학회지
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• 제13권4호
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• pp.437-443
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• 1984

포도당으로 perfusion한 쥐의 뒷다리 근육에 전기자극으로 근육운동을 유도하여 대사물의 농도변화를 측정한 결과는 아래와 같다. 근육내의 구연산회로대사물, 피루빅산, 젖산등의 농도가 상당히 증가하였고 알라닌, 글루타믹산, 아스파틱산등의 아미노산은 약간 증가하였고, 크레아틴 포스페이트, ATP의 농도가 급강하 한데 반하여 AMP와 암모니아의 농도가 증가하였다. 이 결과는 운동시에 에너지대사를 촉진시키는 구연산회로 대사물 일부는 아미노산으로부터 transamination 반응을 통하여 공급되고, 일부는 purine nucleotidecycle반응을 통하여 아스파틱산으로 공급되고 있음을 밝혔다.