• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1133-1140
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• 2018

Pseudomonas fluorescens KLR101 was found to be capable of producing polyhydroxyalkanoate (PHA) using various sugars and fatty acids with carbon numbers ranging from 2 to 6. The PHA granules consisted mainly of a poly(3-hydroxybutyrate) homopolymer and/or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer. Genomic DNA of P. fluorescens was fractionated and cloned into a lambda library, in which a 5.8-kb fragment that hybridized to a heterologous phaC probe from Ralstonia eutropha was identified. In vivo expression in Klebsiella aerogenes KC2671 (pUMS), restriction mapping, Southern hybridization experiments, and sequencing data revealed that PHA biosynthesis by P. fluorescens relied upon a polypeptide encoded by a 1,683-bp non-operonal ORF, which was preceded by a possible -24/-12 promoter and highly similar to DNA sequences of a gene encoding PHA synthase in the genus Pseudomonas. In vivo expression of the putative PHA synthase gene ($phaC_{Pf}$) in a recombinant Escherichia coli strain was investigated by using glucose and decanoate as substrates. E. coli (${phaC_{Pf}}^+$, pUMS) grown in medium containing glucose accumulated PHA granules consisting mainly of 3-hydroxybutyrate, whereas only a trace amount of 3-hydroxydecanoate was detected from an E. coli fadR mutant (${phaC_{Pf}}^+$) grown in medium containing decanoate. In vitro enzymatic assessment experiments showed that 3-hydroxybutyryl-CoA was efficiently used as a substrate of purified $PhaC_{Pf}$, suggesting that the putative PHA synthase of P. fluorescens utilizes mainly short-chain-length PHA precursors as a substrate.

• 생명과학회지
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• 제19권1호
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• pp.138-146
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• 2009

마늘은 역학조사에 의하면 각종 질환의 예방과 치료에 효능이 있는 것으로 알려져 있다. 마늘의 주요 성분인 알리신 성분은 매우 불안정하여 쉽게 분해되어 새로운 형태의 유황 화합물로 만들어져 이들 성분들이 상승적으로 작용하여 중요한 생리황성을 갖는 것으로 알려져 있다. 시판되고 있는 여러 종류의 마늘제품 중에서 숙성마늘제품이 다른 제품에 비하여 생리활성이 높은 것으로 보고되었다. 숙성마늘제품은 마늘을 일정한 조건으로 숙성시킬 때 수용성 성분인 S-allylcysteine, S-allylmercaptan, steroid saponins, te-trahydro-${\beta}$-caboline derivatives 및 fructeosyl-arginine 등이 많이 증가하여 그 효능이 상승적으로 높아지는 것으로 알려져 있다. 따라서 시판 마늘가공품의 품질을 표준화하기 위하여 이들 수용성 성분을 biomarker로서 규격기준을 정해야 할 것이다.

• Applied Biological Chemistry
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• 제43권1호
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• pp.18-23
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• 2000

찹쌀 14 품종의 전분 미세구조는 효소처리에 의해서 debranching시킨 전분의 glucose chain length 분포 비교에 의해서 수행되었고, 찹쌀 품종별로 미세구조상에 차이가 있었다. 짧은 쇄장을 다량 함유하고 있는 찰품종은 병곡이었으며, 상대적으로 긴 쇄장을 다량 함유하고 있는 품종은 TP2579Al이었다. 15% $H_2SO_4$에 대한 가수분해도는 샤레벼-152-1-B가 가장 높았으며, 산동 47이 가장 낮았다. X선 회절도는 14 품종 찹쌀 모두 전형적인 A형이었다. Glucoamylase에 의한 가수분해도의 양상은 품종에 따라 차이가 있었으며, 거창 1 및 병곡은 $37^{\circ}C$에서 3시간 작용시킴에 의해 100% 가수분해 되었다.

• 동의생리병리학회지
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• 제22권2호
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• pp.333-339
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• 2008

Korean ginseng (Panax ginseng C. A. Meyer) has been used as an important medicinal plant in the Orient for a long time. It has been claimed that ginseng has many beneficial bioactive effects on human health, such as antitumor, antistress, antiaging and enhancing immune functions. Red ginseng possibly have new ingredients converted during steaming and dry process from fresh ginseng. Kujeungkupo method which means 9 repetitive steaming and drying process was used for the processes of green tea, Polygonatum odoratum, and Rehmanniae radix preparata. In this study, ingredient conversion of ginseng by 9 repetitive steaming and drying process were investigated measuring conversion efficiency of brown materials, crude lipids, crude proteins and aromatic compounds. Brown materials, as an antioxidant, in red ginseng were produced through non-enzymatic reaction by heat. Repetitive steaming and drying treatments on ginseng root contiunously increased the content of brown materials and the chromaticity. Crude lipids were degraded by heat and converted into volatile aromatic ingredients. Crude lipids were degraded and decreased by 0.52% after the 5th and 7th. Crude proteins were also decomposed and converted to amino acid. Crude proteins after the 9th treatment were decreased by more than 85% as increased times of treatments. A bicyclogermacrene as aromatic material was decreased as increased treatment times, while but a aromatic caramel was increased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.114.1-114.1
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• 2011

Bioenergy production from lignocellulosic biomass and agriculture wastes have been attracted because of its sustainable and non-edible source. Especially, canola is considered as one of the best feedstock for renewable fuel production. Oil extracted canola and its agriculture residues are reuseable for bioethanol production. However, a pretreatment step is required before enzymatic hydrolysis to disrupt recalcitrant lignocellulosic matrix. To increase the sugar conversion, more efficient pretreatment process was necessary for removal of saccharification barriers such as lignin. Alkaline pretreatment makes the lignocellulose swollen through solvation and induces more porous structure for enzyme access. In our previous work, aqueous ammonia (1~20%) was utilized for alkaline reagent to increase the crystallinity of canola residues pretreatment. In this study, significant factors for efficient soaking in aqueous ammonia pretreatment on canola residues was optimized by using the response surface method (RSM). Based on the fundamental experiments, the real values of factors at the center (0) were determined as follows; $70^{\circ}C$ of temperature, 17.5% of ammonia concentration and 18 h of reaction time in the experiment design using central composition design (CCD). A statistical model predicted that the highest removal yield of lignin was 54% at the following optimized reaction conditions: $72.68^{\circ}C$ of temperature, 18.30% of ammonia concentration and 18.30 h of reaction time. Finally, maximum theoretical yields of soaking in aqueous ammonia pretreatment were 42.23% of glucose and 22.68% of xylose.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.198-198
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• 2011

Organocatalysis is a relatively new and popular area within the field of chiral molecule synthesis. It is one of the main branches of enantioselective synthesis with enzymatic and organometallic catalysis. In recent years, immense high quality studies on catalysis by chiral secondary amines were reported. These progresses instantly led to different organocatalytic activation concepts, so thousands of researchers from academia and the chemical industry are currently involved in this field and new ideas, new approaches, and creative thinking have been rapidly emerged. Organocatalysts, some of which are natural products, appear to solve the problems of metal catalysts. Compared to metal-based catalysis, they have many advantages including savings in cost, time, and energy, easier experimental procedure, and reduction of chemical waste. These benefits originate from the following factors. First, organocatalysts are generally stable in oxygen and water in the atmosphere, there is no need for special equipments or experimental techniques to operate under anhydrous or anaerobic conditions. Second, organic reagents are naturally available from biological materials as single enantiomers that they are easy and cheap to prepare which makes them suitable for small-scale to industrial-scale reactions. Third, in terms of safety related catalysis, small organic molecules are non-toxic and environmentally friendly. Therefore, the purpose of this research is to develop novel synthetic methods and design for various organocatalyst. Furthermore, it is expected that these organocatalysts can be applied to a variety of asymmetric reactions and study the transition state of these reactions using a metal sulface. Here, we report the synthesis of unprecedented organocatalysts, proline and pyrrolidine derivatives with quaternary carbon center.

• 한국식품위생안전성학회지
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• 제6권3호
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• pp.127-131
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• 1991

보리와 밀 맥아의 ${\alpha}-amylase$와${\beta}-amylase$의 대한 찹쌀과 멥쌀 전분에 대한 반응속도론적 연구를 수행하였다. 보리와 밀의 발아 과정에서 ATP 함량은 발아 2일 후에 급격하게 증가하여 5일 후에는 감소하였으며, 건조 중량은 3일 후부터 감소하였다. 보리맥아와 밀 맥아의 ${\alpha}-amylase$와$\;{\beta}-amylase$ 모두 6일째에 최대의 활성을 나타내었다. ${\alpha}-amylase$의 경우, 보리맥아에 존재하는 ${\alpha}-amylase$가 멥쌀 전분에서 친화력이 크게 나타났으며, $V_{max}$값은 보리 맥아의 경우 멥쌀 전분에서 밀 맥아의 경우 멥쌀과 찹쌀 전분에서 높게 나타났다. ${\beta}-amylase$의 경우는 보리 맥아의 효소가 찹쌀 전분에 대해 친화력이 크게 나타났으며, $V_{max}$값은 밀 맥아의 효소가 찹쌀 전분에서 높게 나타났다. 또한 기질 효율성은 보리 맥아에서 추출한 ${\beta}-amylase$가 멥쌀 전분에서 가장 우수하였다.

• 한국식품영양학회지
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• 제11권2호
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• pp.150-158
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• 1998

한국산 맥주 3종류, 일본산 맥주 21종류의 한계 덱스트린을 에탄올 침전법으로 분리하였다. 한계 덱스트린의 양은 평균 1.1%로 전체 당 3.15%의 34.5%를 나타냈다. FPLC 분석 결과 한계 덱스트린은 평균 글루코오스 잔기 25개 정도로 형성된 것으로 나타났다. 1H-NMR 분석으로 한계 덱스트린의 $\alpha$-1, 4-결합에 대한 $\alpha$-1, 6-결합의 비율은 평균 1:0.183을 나타냈다. 한계 덱스트린을 $\alpha$-아밀라아제와 $\alpha$-글로코시다아제로 5시간 가수분해 하여 소화성을 평가한 결과 평균 57.22% 가수분해 되었다. 그 중 한국산 맥주의 한계 덱스트린이 가장 높은 소화성 70.38%를 나타냈다. 아밀라아제로 소화된 부분과 에탄올 침전법으로 상징액으로 제거된 작은 당을 합하면 평균 86%가 소화성 당으로, 14%가 비피두스균 증식 인자로 평가된다.

• 한국식품과학회지
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• 제15권3호
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• pp.287-294
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• 1983

3가지 다른 조건하에서 제조된 압출보리와 생보리를 0.31 및 0.71의 수분활성과 $25^{\circ}C$ 및 $40^{\circ}C$의 온도에서 각각 4개월 저장하면서 색도, 갈색화지수, 가용성 단백질, 환원당 및 유효성 리진의 변화에 대한 수분활성과 온도의 영향에 대하여 연구하였다. 저장기간의 경과와 함께 수분활성과 온도가 증가함에 따라 모든 시료에서 백색도의 손실이 증가하였다. 생보리는 압출보리보다 저장중 갈색화 지수의 증가가 심하였고, 설탕을 첨가하여 제조한 압출보리는 다른 압출보리보다 저장중 갈색화가 적었다. 수분활성과 온도가 증가함에 따라 모든 시료중의 환원당, 가용성 단백질 및 유효성 리진의 함량이 감소하였으며, 이와같은 결과는 저장중 Maillard반응에 의한 것임을 알았다.

• Molecules and Cells
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• 제25권3호
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• pp.368-375
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• 2008

Approximately 120 UDP-glycosyltransferases (UGTs), which are classified into 14 distinct groups (A to N), have been annotated in the Arabidopsis genome. UGTs catalyze the transfer of sugars to various acceptor molecules including flavonoids. Previously, UGT71C1 was shown to glycosylate the 3-OH of hydroxycinnamates and flavonoids in vitro. Such secondary metabolites are known to play important roles in plant growth and development. To help define the role of UGT71C1 in planta, we investigated its expression patterns, and isolated and characterized a loss-of-function mutation in the UGT71C1 gene (named ugt71c1-1). Our analyses by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), microarray data mining, and histochemical detection of GUS activity driven by the UGT71C1 promoter region, revealed the tissue-specific expression patterns of UGT71C1 with highest expression in roots. Interestingly, upon treatment with methyl viologen (MV, paraquat), ugt71c1-1 plants displayed enhanced resistance to oxidative stress, and ROS scavenging activity was higher than normal. Metabolite profiling revealed that the levels of two major glycosides of quercetin and kaempferol were reduced in ugt71c1-1 plants. In addition, when exposed to MV-induced oxidative stress, eight representative ROS response genes were expressed at lower levels in ugt71c1-1 plants, indicating that ugt71c1-1 probably has higher non-enzymatic antioxidant activity. Taken together, our results indicate that ugt71c1-1 has increased resistance to oxidative stress, suggesting that UGT71C1 plays a role in some glycosylation pathways affecting secondary metabolites such as flavonoids in response to oxidative stress.