• 한국미생물·생명공학회지
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• 제27권1호
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• pp.8-14
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• 1999

This study was developed to evaluate the growth inhibition effects of cell wall components of Enterococcus faecalis 2B4-1 obtained from feces of neonates against tumor cell lines. Polysaccharide fraction (PS) shown sensitive growth inhibition effect in the cell wall components was isolated and characterized. In growth inhibition effects, residue fractin of whole cell was shown sensitive level of percent survival about 30% when administrated at ehe concentration of 100${\mu}$g/ml, and that was more effective than that of supernatant fraction against the tumor cell lines, SNU-1, 3LL, FARROW and HEC-1-B. Sensitive growth inhibition effects against SNU-1, FARROW and HEC-1-B were performed by whole cell (WC) fraction from Ent. faecalis 2B4-1. Cytoplasm fractin (CP) of WC was shown non-inhibition effect, however, the other part of WC, precipitate of disrupted cell (PD), was sensitive against the tumor cell line mentioned above. Followed by separation to peptidoglycan fraction (PG) and polysaccharide fraction (PS) were all sensitive which the latter was shown more sensitive percent survival than the former. Composed sugars of polysaccharide fraction were determined to D-glucose, L-rhamnose and D-glucosamine, and the rate fo composition was calculated to about 1:1:1 by the data of elemental analysis, IR, TLC and HPLC.

• BMB Reports
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• 제33권2호
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• BMB Reports
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• 제28권2호
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• pp.112-117
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• 1995

Succinic semialdehyde reductase was inactivated by o-phthalaldehyde. The inactivation followed pseudo-first order kinetics, and the second-order rate constant for the inactivation process was 28 $M^{-1}s^{-1}$ at pH 7.4 and $25^{\circ}C$. The absorption spectrum ($\lambda_{max}$ 337 nm) and fluorescence excitation ($\lambda_{max}$ 340 nm) and fluorescence emission spectra ($\lambda_{max}$ 409 nm) were consistent with the formation of an isoindole derivative in the catalytic site between a cysteine and a lysine residue approximately about 3 $\AA$ apart. The substrate, succinic semialdehyde, did not protect enzymatic activity against inactivation, whereas the coenzyme NADPH protected against o-phthaladehyde induced inactivation of the enzyme. About 1 isoindole group per mol of the enzyme was formed following complete loss of enzymatic activity. These results suggest that the amino acid residues of the enzyme participating in a reaction with o-phthalaldehyde are cysteinyl and lysyl residues at or near the NADPH binding site.

• 한국환경농학회지
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• 제28권4호
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• pp.397-402
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• 2009

In Korea, salt stress is one of the major problems limiting crop production and eco-environmental quality in greenhouse soil. The objective of this study was to evaluate the effectiveness of organic residues (Chinese milk vetch, maize stalk, rice straw, and rye straw) for reducing salt activity in greenhouse soil. Organic residues was incorporated with salt-accumulated soil (EC, 3.0 dS $m^{-1}$) at the rate of 5% (wt $wt^{-1}$) and the changes of electrical conductivity (EC) was determined weekly for 8 weeks under incubation condition at $30^{\circ}C$. The EC, microbial biomass carbon (MBC), and water soluble ions in soil was strongly affected by C/N ratio of organic residues. After 8 weeks incubation, the concentration of water soluble $NO_3{^-},\;Ca^{2+}$, and $Mg^{2+}$ was significantly decreased in organic residues having high C/N ratio (maize stalk, rice straw, and rye straw) incorporated soil compared to organic residues having lower C/N ratio (Chinese milk vetch) incorporated soil. The EC value in Chinese milk vetch incorporated soil was higher than control treatment. In contrast, maize stalk, rice straw, and rye straw amended soil was highly decreased the EC value compared to control and Chinese milk vetch applied soil after 4 weeks incubation. Our results indicated that incorporation of organic residues having high C/N ratio (>30) could reduce salt activity resulting from reducing concentration of water soluble ions.

• 한국멀티미디어학회논문지
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• 제15권4호
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• pp.485-491
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• 2012

본 논문은 움직임 벡터와 함께 Coding Unit (CU)의 분할 정보를 표현하기 위해 쿼드트리 기반의 Coding Unit Tree (CUT)를 제안한다. 새로운 동영상 국제 표준안인 High Efficiency Video Coding (HEVC)는 높은 압축 효율을 위해 다양한 새로운 기술들을 채택하였다. 그리고 CU, prediction Unit (PU), 와 Transform Unit (TU)라는 분할 개념을 도입하였다. 그중 기본 부호화 단위인 CU는 H.264/AVC의 매크로 블록보다 다양한 크기를 제공하며 계층적인 구조를 가지고 있으며 쿼드트리 기반의 영상을 분할하고 처리한다. 이러한 구조는 유연성과 최적화를 이룰 수 있는 기반을 제공하고 있으나, 분할 정보에 대한 오버헤더가 발생한다. 복잡한 움직임 정보가 발생하면, 해당하는 정보를 전송하기 위해 다양한 신호가 발생한다. 본 논문에서는 이러한 다양한 신호들을 분석하고, 중복되는 정보를 제거하기 위한 알고리즘을 제안한다. 제안하는 알고리즘 은 기본 블록인 $2{\times}2$ 블록을 기준으로 계층적인 구조를 제안한다. 제안하는 알고리즘은 쿼드트리 기반의 타입 코드로 영상을 구조를 나타내고, 대표 값과 잔여 값으로 각 노드의 값을 표현한다. 결과에서 제안하는 알고리즘이 HM1.0보다 13.6% 압축 향상을 보여준다.

• BMB Reports
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• 제33권4호
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• pp.317-320
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• 2000

The succinic semialdehyde dehydrogenase from bovine brain was inactivated by treatment with phenylglyoxal, a reagent that specifically modifies arginine residues. The inhibition at various phenylglyoxal concentrations shows pseudo-first-order kinetics with an apparent secondorder rate constant of 30 $M^{-1}min^{-1}$ for inactivation. Partial protection against inactivation was provided by the coenzyme $NAD^+$, but not by the substrate succinic semialdehyde. Spectrophotometric studies indicated that complete inactivation of the enzyme resulted from the binding of 2 mol phenylglyoxal per mol of enzyme. These results suggest that essential arginine residues, located at or near the coenzyme-binding site, are connected with the catalytic activity of brain succinic semialdehyde dehydrogenase.

• 한국산학기술학회논문지
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• 제9권4호
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• pp.1059-1066
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• 2008

열중량반응기와 미분반응기를 이용하여 ABS의 역분해 및 생성물분포 특성을 연구하였으며 미분반응기를 이용한 실험의 열분해온도는 $400\sim450^{\circ}C$이었다. 각 상의 열분해생성물의 수율은 무게측정을 통해 얻었으며 액상생성물의 탄소수분포는 GC-SIMDIS 방법을 통해 측정하였다. 열중량분석실험에서는 측정할 수 없었던 다량의 고상잔류물의 생성을 회분식 미분반응기실험을 통해 확인학 수 있었다. 반응온도와 시간이 증가할수록 액상생성물의 수율과 평균분자량은 감소하였으나 액상생성물 중의 스티렌모노머의 생성은 두드러지게 증가하였다. ABS 열분해 반응에서 말단절단의 속도계수인 활성화에너지 값은 54.1kcal/mole이었다.

• 한국응용과학기술학회지
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• 제29권2호
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• pp.268-277
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• 2012

폐 PVC전선의 열적분해 특성에 관한 연구를 TGA 및 고정층 반응기를 이용하여 연구하였다. 본 연구에서는 분해온도, 공기유량 및 CaO/ PVC의 비를 실험조건으로 고려하였으며, PVC전선의 열적분해과정에서 발생되는 염화수소 및 독성가스의 제거를 위한 CaO의 첨가에 대한 효과를 검증하기 위하여 PVC 전선의 열적분해 과정에서 생성되는 기상 생성물을 GC/MS를 이용하여 분석하였다. 또한 CaO의 첨가효과를 고찰하고자 액성 생성물에 대한 GC/MS을 함께 수행하였으며, 분해온도, 공기유량 및 CaO/PVC의 비에 따른 액상, 기상 및 고상 잔류물의 수율 변화를 함께 고찰하였다. 본 연구로부터 CaO의 첨가량이 증가할수록 PVC의 열적분해 과정에서 발생되는 염화수소의 제거량이 증가함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1707-1716
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• 2019

The development of new antimicrobial agents is essential for the effective treatment of diseases such as sepsis. We previously developed a new short peptide, Pap12-6, using the 12 N-terminal residues of papiliocin, which showed potent and effective antimicrobial activity against multidrug-resistant Gram-negative bacteria. Here, we investigated the antimicrobial mechanism of Pap12-6 and a newly designed peptide, Pap12-7, in which the 12^th Trp residue of Pap12-6 was replaced with Val to develop a potent peptide with high bacterial selectivity and a different antibacterial mechanism. Both peptides showed high antimicrobial activity against Gram-negative bacteria, including multidrug-resistant Gram-negative bacteria. In addition, the two peptides showed similar anti-inflammatory activity against lipopolysaccharide-stimulated RAW 264.7 cells, but Pap12-7 showed very low toxicities against sheep red blood cells and mammalian cells compared to that showed by Pap12-6. A calcein dye leakage assay, membrane depolarization, and confocal microscopy observations revealed that the two peptides with one single amino acid change have different mechanisms of antibacterial action: Pap12-6 directly targets the bacterial cell membrane, whereas Pap12-7 appears to penetrate the bacterial cell membrane and exert its activities in the cell. The therapeutic efficacy of Pap12-7 was further examined in a mouse model of sepsis, which increased the survival rate of septic mice. For the first time, we showed that both peptides showed anti-septic activity by reducing the infiltration of neutrophils and the production of inflammatory factors. Overall, these results indicate Pap12-7 as a novel non-toxic peptide with potent antibacterial and anti-septic activities via penetrating the cell membrane.

• 대한화학회지
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• 제25권4호
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• pp.283-290
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• 1981

N,N-디메틸포름아미드용매내 반응온도 50∼$90^{\circ}C$범위에서 과량의 슈크로오스와 라우르산, 미리스트산, 팔미트산, 스테아르산 그리고 올레산등 5종의 지방산 메틸에스테르와의 에스테르 교환반응에서 반응속도를 측정하여 반응속도정수, 활성화파라미터등을 구하여 고찰하였다. 이 반응은 본 실험범위내에서 유사 1차반응으로 진행하고 반응의 순서는 주로 메틸에스테르의 지방산기의 구조변화에 의존하면 라우르산메틸, 미리스트산메틸, 팔미트산메틸 올레산메틸 그리고 스테아르산 메틸의 순으로 반응되기 힘들어지는 엔탈피조절반응이라 생각된다. 한편 이들 각각의 활성화에너지는 9.3, 9.9, 10.3, 10.9 그리고 11.1 kcal/mole이 얻어졌다.