Substrate specificity of a recombinant d-lyxose isomerase from Providencia stuartii for monosaccharides

Kwon, H.J.,Yeom, S.J.,Park, C.S.,Oh, D.K. Society for Bioscience and Bioengineering, Japan ; 2010 Journal of bioscience and bioengineering Vol.110 No.1

The specific activity and catalytic efficiency (k<SUB>cat</SUB>/K<SUB>m</SUB>) of the recombinant putative protein from Providencia stuartii was the highest for d-lyxose among the aldose substrates, indicating that it is a d-lyxose isomerase. Gel filtration analysis suggested that the native enzyme is a dimer with a molecular mass of 44 kDa. The maximal activity for d-lyxose isomerization was observed at pH 7.5 and 45 <SUP>o</SUP>C in the presence of 1 mM Mn<SUP>2+</SUP>. The enzyme exhibited high isomerization activity for aldose substrates with the C2 and C3 hydroxyl groups in the left-hand configuration, such as d-lyxose, d-mannose, l-ribose, d-talose, and l-allose (listed in decreasing order of activity). The enzyme exhibited the highest activity for d-xylulose among all pentoses and hexoses. Thus, d-lyxose was produced at 288 g/l from 500 g/l d-xylulose by d-lyxose isomerase at pH 7.5 and 45 <SUP>o</SUP>C for 2 h, with a conversion yield of 58 % and a volumetric productivity of 144 g l<SUP>-1</SUP> h<SUP>-1</SUP>. The observed k<SUB>cat</SUB>/K<SUB>m</SUB> (920 mM<SUP>-1</SUP> s<SUP>-1</SUP>) of P. stuartiid-lyxose isomerase for d-xylulose is higher than any of the k<SUB>cat</SUB>/K<SUB>m</SUB> values previously reported for sugar and sugar phosphate isomerases with monosaccharide substrates. These results suggest that the enzyme will be useful as an industrial producer of d-lyxose.

Global Warming Gas Emission during Plasma Cleaning Process of Silicon Nitride Using c-C₄F₈O Feed Gas with Additive N₂

K. J. Kim,C. H. Oh,N.-E. Lee,J. H. Kim,J. W. Bae,G. Y. Yeom,S. S. Yoon 한국표면공학회 2001 한국표면공학회지 Vol.34 No.5

Study of Cryogenic Conduction Cooling Systems for an HTS SMES

Yeom, H.K.,Hong, Y.J.,Park, S.J.,Seo, T.B.,Seong, K.C.,Kim, H.J. IEEE 2007 IEEE transactions on applied superconductivity Vol.17 No.2

<P>Superconducting magnetic energy storage (SMES) is more fast response, economical, and environment-friendly than uninterruptible power supply (UPS) using the battery. And the SMES not only has the ability to control active and reactive power simultaneously, but also has a long life time because the superconducting magnet does not have degradation problem which the battery has. Therefore, the SMES is a candidate for instead of the UPS using the battery. The SMES needs cryogenic system without exception. A conduction cooling system that has a simple, light and small structure is well adapted to high temperature superconducting (HTS) SMES. The cryogenic conduction cooling system is needed some technologies such as insulation, vacuum, and thermal analysis. Conduction heat is mainly transferred by cooler port, access port, support bar, etc., and radiation heat is transferred by vacuum chamber, thermal shield and HTS coil surface. The heat loads through the conduction and radiation of cryostat are calculated. Radiation shield heat load, temperature of HTS coil and conduction copper plate are estimated and measured. A cryopumping effect of cooled radiation shield was observed. A current lead and HTS coil heat load was evaluated to maintain HTS coil temperature was under 20 K.</P>

Substrate specificity of a recombinant <small>D</small>-lyxose isomerase from <i>Serratia proteamaculans</i> that produces <small>D</small>-lyxose and <small>D</small>-mannose

Park, C.-S.,Yeom, S.-J.,Lim, Y.-R.,Kim, Y.-S.,Oh, D.-K. Blackwell Publishing Ltd 2010 Letters in applied microbiology Vol.51 No.3

<P>Abstract</P><P>Aims: </P><P>Characterization of substrate specificity of a <SMALL>D</SMALL>-lyxose isomerase from <I>Serratia proteamaculans</I> and application of the enzyme in the production of <SMALL>D</SMALL>-lyxose and <SMALL>D</SMALL>-mannose.</P><P>Methods and Results: </P><P>The concentrations of monosaccharides were determined using a Bio-LC system. The activity of the recombinant protein from <I>Ser. proteamaculans</I> was the highest for <SMALL>D</SMALL>-lyxose among aldoses, indicating that it is a <SMALL>D-</SMALL>lyxose isomerase. The native recombinant enzyme existed as a 54-kDa dimer, and the maximal activity for <SMALL>D-</SMALL>lyxose isomerization was observed at pH 7·5 and 40°C in the presence of 1 mmol l<SUP>−1</SUP> Mn<SUP>2+</SUP>. The <I>K</I><SUB>m</SUB> values for <SMALL>D</SMALL>-lyxose, <SMALL>D</SMALL>-mannose, <SMALL>D</SMALL>-xylulose, and <SMALL>D</SMALL>-fructose were 13·3, 32·2, 3·83, and 19·4 mmol l<SUP>−1</SUP>, respectively. In 2 ml of reaction volume at pH 7·5 and 35°C, <SMALL>D</SMALL>-lyxose was produced at 35% (w/v) from 50% (w/v) <SMALL>D</SMALL>-xylulose by the <SMALL>D-</SMALL>lyxose isomerase in 3 h, while <SMALL>D</SMALL>-mannose were produced at 10% (w/v) from 50% (w/v) <SMALL>D</SMALL>-fructose in 5 h.</P><P>Conclusions: </P><P>We identified the putative sugar isomerase from <I>Ser. proteamaculans</I> as a <SMALL>D</SMALL>-lyxose isomerase. The enzyme exhibited isomerization activity for aldose substrates with the C2 and C3 hydroxyl groups in the left-hand configuration. High production rates of <SMALL>D-</SMALL>lyxose and <SMALL>D</SMALL>-mannose by the enzyme were obtained.</P><P>Significance and Impact of the Study: </P><P>A new <SMALL>D-</SMALL>lyxose isomerase was found, and this enzyme had higher activity for <SMALL>D</SMALL>-lyxose and <SMALL>D</SMALL>-mannose than previously reported enzymes. Thus, the enzyme can be applied in industrial production of <SMALL>D</SMALL>-lyxose and <SMALL>D</SMALL>-mannose.</P>

5-Bromo-2--deoxyuridine induced effluvium via p53-mediated CD326-positive keratinocyte apoptosis in C57BL/6 mice

Uh, K. J.,Hwang, W. S.,Bae, J. H.,Jang, D. E.,Yeom, S. C. Blackwell Publishing Ltd 2017 The Journal of Dermatology Vol.44 No.2

<P>Anagen effluvium develops because of disturbances in the hair follicle cycle, leading to acute and severe hair loss in humans. The objective of this study was to establish a mouse model of anagen effluvium by 5-bromo-2-deoxyuridine (BrdU) treatment, and evaluate the pathological changes and underlying mechanisms. We treated 9-10-day-old pups and 3-7-week-old C57BL/6 mice with BrdU. After successfully inducing hair loss in the neonatal pups, microscopic, immunohistochemical and flow cytometry analyses were conducted. BrdU induced early onset alopecia in neonates and caused epidermal thickening and hair shaft breakage. BrdU appeared to incorporate the CD326-positive keratinocyte layer and induced p53-related apoptosis. Keratinocyte apoptosis caused immune cell infiltration in the dermal region; M2 macrophages and neutrophils were dominant. The BrdU-induced hair loss was dose-dependent, and alopecia was visible at a dose range of 25-200 g/g bodyweight. The BrdU-induced anagen effluvium mouse model is novel and easily established by administrating four simple BrdU injections to pups; these mice showed synchronized onset of alopecia symptoms with little individual variation. Moreover, this model showed an alopecia phenotype similar to that of human anagen effluvium with acute, severe and widespread hair loss.</P>

디젤 분무와 천연 가스 분류의 거동 특성에 관한 기초 연구

염정국(J. K. Yeom),김민철(M. C. Kim) 한국동력기계공학회 2009 동력시스템공학회지 Vol.13 No.6

This basic study is required to examine spray or jet behavior depending on fuel phase. In this study, analyses of diesel fuel(n-Tridecane, C13H28) spray and natural gas fuel(Methane, CH4) jet under high temperature and pressure are performed by a general-purpose program, ANSYS CFX release 11.0, and the results of these are compared with experimental results of diesel fuel spray using the exciplex fluorescence method. The simulation results of diesel spray is analyzed by using the combination of Large-Eddy Simulation(LES) and Lagrangian Particle Tracking(LPT) and of a natural gas jet is analyzed by using Multi-Component Model(MCM). There are two study variables considered, that is, ambient pressure and injection pressure. In a macroscopic analysis, the higher ambient pressure is, the shorter spray or jet tip penetration is at each time after start of injection. And the higher injection pressure is, the longer spray or jet tip penetration is at each time after start of injection. When liquid fuel is injected, droplets of the fuel need some time to evaporate. However, when natural gas fuel is injected, the fuel does not need time to evaporate. Gas fuel consists of minute particles. Therefore, the gas fuel is mixed with the ambient gas more quickly at the initial time of injection than the liquid fuel is done. The experimental results also validate the usefulness of this analysis.

Effect of pulse phase lag in the dual synchronized pulsed capacitive coupled plasma on the etch characteristics of SiO₂ by using a C₄F₈/Ar/O₂ gas mixture

Jeon, M.H.,Yang, K.C.,Kim, K.N.,Yeom, G.Y. Pergamon Press [etc.] 2015 Vacuum Vol.121 No.-

The characteristics of a synchronized pulse plasma using 60 MHz radio frequency as a source power and 2 MHz radio frequency as a bias power were investigated for the etching of SiO<SUB>2</SUB> masked with an amorphous carbon layer (ACL) in a C<SUB>4</SUB>F<SUB>8</SUB>/Ar/O<SUB>2</SUB> gas mixture. Especially, the effects of the pulse phase lag of the synchronized dual-frequency pulsing between source power and bias power on the characteristics of the plasma and SiO<SUB>2</SUB> etching were investigated. The results showed that the etch rates of SiO<SUB>2</SUB> was the highest and the etch profile was the most anisotropic when the pulse phase lag between the source power and bias power was 0<SUP>o</SUP> in the synchronized pulse plasma. Increasing the phase lag to 180<SUP>o</SUP> decreased the etch rates and degraded the etch anisotropy. The change in etch characteristics as a function of pulse phase lag was believed to be related to the difference in gas dissociation and fluorocarbon passivation caused by the variations in electron temperatures during the source pulse off-time.

Molecular Composition and Fractionation of Colostral Casein with Advancing Lactation

Han, K. S 韓國酪農學會 1997 韓國酪農學會誌 Vol.19 No.1

Fractionation of bovine x-Casein

Kang, S. H 韓國酪農學會 1996 韓國酪農學會誌 Vol.18 No.3

군장병의 헌혈을 통한 말라리아 전파의 위험성에 대한 조사

임채승,김영기,이갑노,염용태,김순덕,김대성,황유성,오홍범,김두성 대한감염학회 1997 감염 Vol.29 No.2

목적:국내 헌혈 혈액에서 전염병 감염 방지를 위해 시행하는 감염표지자 중 말라리아를 검출하려는 노력은 최근의 비무장지대 내의 군장병에서의 말라리아 재발생에도 불구하고 활성화 되어 있지 않다. 일반적으로 말라리아가 토착화 된 지역을 거주하거나 여행한 사람 중 말라리아에 걸렸거나 치료한 경력 있는 사람은 치료가 끝난 후라도 3년내에는 헌혈을 금지하도록 규정하고 있다. 저자들은 국내 헌혈의 중요 부분(57.8%)을 차지하는 군인에서 헌혈시 말라리아 전파의 위험성을 파악하고자 본 조사를 실시하였다. 방법:1995년 5월에서 1996년 10월까지 군병원에 입원한 환자중 말라리아로 확진된 174명의 환자에서 면담 및 입원 기록을 추적하여 병력과 헌혈 기록을 확인 한 뒤 헌혈장소, 헌혈일, 헌혈 기록을 확인 한 뒤 헌혈장소, 헌혈일, 헌혈 횟수를 조사하여 환자의 증상 발병일과의 간격 및 연관성 분석하였고 이를 기준으로 공혈 혈액의 수혈시 말라리아의 전파 위험성을 평가하였다. 결과:전체 174명의 환자중에서 1회라도 헌혈을 시행한 사람은 70.7%인 123명에 해당하였고 환자의 증상 시작일과 헌혈일과의 간격은 2일에서 평균 2750일(평균 377알, 표준편차 488일)의 분포를 보였다. 증상시작일과 헌혈일의 간격이 3년 이내인 경우는 전체의 87.8%에 해당하였다. 말라리아 치료후 헌혈을 실시한 경우는 (n=18) 모두 치료 후 3년 이내에 헌혈을 하였다. 헌혈장소는 토착형 말라리아의 호발 지역과 동일하였는데 경기도 파주시(40%)와 연천군(29%) 및 철원(15.5%) 기타(15.5%)순이었다. 결론:한국에서 토착형 말라리아 군인 환자들의 병력조회에서 헌혈에 의한 전염가능성이 존재하는 기간 내에 헌혈이 적지 않게 실시되고 있어서 이들 지역에서의 군헌혈을 실시하는 경우 엄격한 헌혈자 선별기준 적용되어야 할 것으로 생각된다. Background: Screening of donor blood for malaria has not been activated in Korea yet in spite of the recent resurgence of tertian malaria among Korean army soldiers in Delimited Militarized Zone areas. Prospective donors(travellers, immigrants, refugees, citizens or residents) following a visit to or coming from and endemic area who have had malaria or taken antimalarial prophylaxis should be deferred for 3 years after cessation of therapy or after depature from malarial area. We studied the risk of the transmission of malaria, especially through army blood donation which comprised up to 57.8% of whole blood donation in Korea. Methods: The data were collected by personal interview and review of donation records of Korea Red Cross Center and medical records from 174 army soldiers with malaria who admitted to Army Hospital from May 1995 to October 1996. We analysed the time interval between onset of illness and blood donation, and geographic distribution of the patients. Results: About 70.7%(123/174) of the patients donated blood before the onset of illness, and the internal between blood donation and onset of illness ranged from 2 days to 2,750 days (mean 377, standard deviation488). Patients who donated blood within 3 years before onset of illness were 87.8%(n=108) of the total blood donation. All donation (n=18) after treatment were within 3 years from 46 days to 342 days(mean 138, standard deviation 80.7). The frequent of blood donations were from the prevalent areas of malaria such as Pajoo City(40%), Younchon Kun(29%), Cholwon Kun(15.5%) and others(15.5%). Conclusion: We showed that donated army blood a risk of malaria transmission. Therefore the blood bank needs to set strict guidelines for blood donation especially from Korean army soldiers to control malaria transmission.