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.

T_c and J_c distribution in in situ processed MgB₂ bulk superconductors with/without C doping

Kim, C.J.,Kim, Y.J.,Lim, C.Y.,Jun, B.H.,Park, S.D.,Choo, K.N. The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.2

Temperature dependence of magnetic moment (m-T) and the magnetization (M-H) at 5 K and 20 K of the in situ processed $MgB_2$ bulk pellets with/without carbon (C) doping were examined. The superconducting critical temperature ($T_c$), the superconducting transition width (${\delta}T$) and the critical current density ($J_c$) were estimated for ten test samples taken from the $MgB_2$ bulk pellets. The reliable m-T characteristics associated with the uniform $MgB_2$ formation were obtained for both $MgB_2$ pellets. The $T_cs$ and ${\delta}Ts$ of all test samples of the undoped $MgB_2$ were the same each other as 37.5 K and 1.5 K, respectively. The $T_cs$ and ${\delta}Ts$ of the C-doped $MgB_2$ were 36.5 K and 2.5 K, respectively. Unlike the m-T characteristics, there existed the difference among the M-H curves of the test samples, which might be caused by the microstructure variation. In spite of the slight $T_c$ decrease, the C doping was effective in enhancing the $J_c$ at 5 K.

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>

Effect of Feeding Cyanidin 3-glucoside (C3G) High Black Rice Bran on Nutrient Digestibility, Blood Measurements, Growth Performance and Pork Quality of Pigs

Kil, D.Y.,Ryu, S.N.,Piao, L.G.,Kong, C.S.,Han, S.J.,Kim, Y.Y Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.12

Two experiments were conducted to investigate the effect of feeding cyanidin 3-glucoside (C3G) high black rice bran on nutrient digestibility, blood measurements, growth performance and pork quality of pigs. In Exp. I, a total of fifteen pigs (19.91${\pm}$1.80 kg, average initial body weight) were used in assay of nutrient digestibility and blood measurements. All pigs were allotted to 5 treatments with 3 replicates according to a completely randomized design (CRD) in an individual metabolic crate. Treatments included 1) CON: basal diet, 2) BRB-2: basal+brown rice bran 2%, 3) BRB-4: basal+brown rice bran 4%, 4) CRB-2: basal+C3G high black rice bran 2% and 5) CRB-4: basal+C3G high black rice bran 4%. The digestibility of dry matter (DM), crude protein (CP), crude fat (CF), crude ash (CA) and crude fiber (CF) was not affected by dietary treatments. Serum triglyceride (TG) and high density lipoprotein (HDL) cholesterol concentrations were not affected by addition of C3G high black rice bran. However, at the end of experiment, pigs fed rice bran showed decreased tendency in total cholesterol concentration. Especially pigs fed C3G high black rice bran showed significantly lower total cholesterol concentration compared to pigs fed brown rice bran (p<0.03). There was numerically lower total cholesterol concentration with increasing levels of black rice bran in the diet. In terms of serum glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), there were no significant differences among treatments, even though pigs fed CRB-4 showed the lowest GOT concentration compared to other pigs. In Exp. II, sixteen finishing pigs (average initial body weight 89.96${\pm}$0.35 kg) were divided into 4 treatments to investigate the effect of feeding C3G high black rice bran on growth performance and pork quality. There were no significant differences in average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) among the treatments. Pigs fed C3G high black rice bran showed numerical decrease in ADG and increase in FCR while not effecting feed intake. There was no significant difference in live weight, carcass weight, carcass rate, backfat thickness and carcass grade. However, pigs fed C3G high black rice bran tended to show lower backfat thickness than pigs fed basal diet. Pigs fed C3G high black rice bran showed a tendency of decreased TBA value than pigs fed basal diet, although there was no overall significant difference among treatments. In conclusion, nutrient digestibility, blood measurements, growth performance and pork quality were not significantly affected by feeding C3G high black rice bran to pigs. However, C3G high black rice bran might have an effect on lowering serum total cholesterol and decrease the TBA value in pork compared to control group and these effects might be due to high concentration of antioxidative compounds in C3G high black rice bran.

An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements.

King, J D,Strait, E J,Boivin, R L,Taussig, D,Watkins, M G,Hanson, J M,Logan, N C,Paz-Soldan, C,Pace, D C,Shiraki, D,Lanctot, M J,La Haye, R J,Lao, L L,Battaglia, D J,Sontag, A C,Haskey, S R,Bak, J G American Institute of Physics 2014 Review of scientific instruments Vol.85 No.8

<P>The DIII-D tokamak magnetic diagnostic system [E. J. Strait, Rev. Sci. Instrum. 77, 023502 (2006)] has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric '3D' fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 n 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic model predictions. Small 3D perturbations, relative to the equilibrium field (10(-5) < δB/B0 < 10(-4)), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 14 BP fluctuation sensors, with that measured by the upgraded B(R) saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.</P>

Holocene environmental change at the southern coast of Korea based on organic carbon isotope (δ¹³C) and C/S ratios

Lim, J.,Lee, J.Y.,Kim, J.C.,Hong, S.S.,Yang, D.Y. Pergamon Press 2015 QUATERNARY INTERNATIONAL Vol.384 No.-

<P>To trace the environmental change that occurred at a coastal area during the Holocene, we performed radiocarbon dating and geochemical analyses using sedimentary cores recovered from the Beolgyo tidal flats on the south coast of Korea. The delta C-13 values of total organic carbon (TOC), which represent relative inputs of terrestrial (or freshwater) and marine organic sources, revealed a long-term increasing trend from -27.5 to -21.7 parts per thousand during the period between 10,000 and 3000 cal BP, suggesting an evolutionary series of fluvial-dominant to marine-dominant environments, coupled with weakened summer monsoon intensity. From 3000 cal BP to the present, the delta C-13(TOC) decreased gradually from -21.7 to -24 parts per thousand, indicating enhancement of freshwater input during this time. The observed long-term environmental change was divided into six stages based on the averages of the total sulfur content (TS%) and the organic carbon to sulfur ratio (C/S), proxies for paleosalinity. On multi-centennial to millennial timescales, higher C/S ratios and lower TS% were linked to higher delta C-13(TOC) values, indicating strong freshwater input at Stage 2 (similar to 8300-7400 cal BP), Stage 4 (similar to 4500-3300 cal BP), and Stage 6 (similar to 1100 cal BP to present). Strong freshwater discharge events synchronously occurred at 4300 cal BP and 3600 cal BP along the south coast of Korea. Further testing should be carried out in other East Asian coastal areas. This study suggests that sedimentary delta C-13(TOC) values and C/S ratios can be used in Asian coastal regions to trace past freshwater input events and summer monsoon intensity during relatively stable sea level periods (e.g., the middle to late Holocene). (C) 2015 Elsevier Ltd and INQUA. All rights reserved.</P>

O-free polyacrylonitrile doping to improve the J_c(B) and H_c2 of MgB₂ wires

Hwang, S.M.,Sung, K.,Choi, J.H.,Kim, W.,Joo, J.,Lim, J.H.,Kim, C.J.,Park, Y.S.,Kim, D.H. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20

We selected polyacrylonitrile (PAN, -[C<SUB>3</SUB>H<SUB>3</SUB>N]-) as an O-free organic dopant and fabricated C-doped MgB<SUB>2</SUB> wires by in situ and powder-in-tube techniques. 0-5 wt.% PAN powders were uniformly mixed with B powder using a liquid mixing method. The precursor powders were mixed with Mg powder, filled into Fe tubes, and then drawn into wires. Sintering was performed at 900<SUP>o</SUP>C for 1h in a flowing Ar gas. The PAN doping decreased the critical temperature (T<SUB>c</SUB>) and a-axis lattice parameter, but significantly improved the critical current density (J<SUB>c</SUB>) in high fields, upper critical field (H<SUB>c2</SUB>), and irreversibility field (H<SUB>irr</SUB>) performances. These results are attributed to the replacement of B sites with C by the PAN doping. Furthermore, as expected, the MgO amount did not increase as the doping content increased. The J<SUB>c</SUB> of the PAN-doped MgB<SUB>2</SUB> wires was more than one order of magnitude higher than that of the undoped MgB<SUB>2</SUB> wire at 5K and 6.6T (1.46-3.82kA/cm<SUP>2</SUP> vs. 0.11kA/cm<SUP>2</SUP>).

주성분 분석을 이용한 거세한우의 체형분류에 관한 연구

하동우,김현철,김병우,이문연,이종헌,신철교,도창희,이정규 한국동물자원과학회 2002 한국축산학회지 Vol.44 No.6

1997년부터 2001년까지 (사)한국종축개량협회의 전국한우능력평가대회에 출품된 642두의 거세한우의 도축 전까지 4회에 걸쳐 주요 10개 부위의 체형 측정치를 조사하여 주성분 분석을 이용하여 체형을 분류하였으며, 각 체형 측정치의 주성분 지수와 도체 형질과의 상관관계를 분석하였으며, 그 결과를 요약하면 다음과 같다. 1. 1차, 2차, 3차 및 4차 체형 측정치의 principal component(이하 P.C) 1의 분산은 각각 7.610, 8.297, 7.269 및 5.736로서 전체분산 중 76.0%, 83.0%, 72.7% 및 57.4%를 나타낼 수 있었고, P.C 1, P.C 2, P.C 3의 합은 전체분산 중 각각 86.69%, 90.49%, 84.62% 및 77.26%를 나타났다. 2. 각 차수별 체형 측정치의 P.C 1의 모든 계수가 양(+)이어서 일반적으로 좋은 체구의 크기를 나타내었으며, 체구의 크기에 가장 크게 영향을 미치는 형질은 흉심(0.328∼0.339)과 요각폭(0.325∼0.341)이였다. 또한 P.C 2, P.C 3 및 P.C 4는 각 차수별로 다양하게 나타났다. 3. 1차, 2차, 3차 및 4차 체형 측정치의 주성분 지수들과 도체형질간의 상관계수 추정에서 대부분의 분산을 차지하는 P.C 1은 도체중(0.539∼0.755), 일당증체량(0.256∼0.564), 등지방두께(0.227∼0.280) 및 배최장근단면적(0.187∼0.344)간에 정(+)의 상관을 보였으며, 육량지수(-0.246∼-0.110)와는 부(-)의 상관을 보였고, 근내지방도(0.066∼0.099)와는 대부분 유의적인 상관을 보이지 않거나 낮은 상관을 보였고, P.C 2, P.C 3 및 P.C 4는 주성분 지수들의 값에 따라 도체형질과 다양한 상관관계를 보였다. 단일 체형형질과 도체형질간의 상관 그리고 P.C 1의 주성분 지수와 도체형질과의 상관간에는 큰 차이가 없었다. Data were consisted of the ten body measurements (withers height, rump height, body length, chest depth, chest width, rump width, rump length, thurls width, hipbone width and chest girth) of 642 steers (Korean cattle), which was entered in the National Beef Quality Contest hosted by the Korea Animal Improvement Association from 1997 to 2001. A principal components analysis was used to classify the body types of the steers, and estimate the correlations between carcass traits and principal components for the body measurements of the first, second, third and fourth period, respectively. The first principal component of body measurements at the first, second, third and fourth period accounted for 76.0%, 83.0%, 72.7% and 57.4% of the total variance, respectively. The sum of first, second and third principal component at each period accounted for 86.69%, 90.49%, 84.62% and 77.26% of the total variance, respectively. At each period, all the first principal component of the body measurements were positive and it generally showed large framed body shape. The size of body was influenced mostly by chest depth(0.328∼0.339) and rump length(0.325∼0.341). The second, third and fourth principal component at the each period were various. There were positive correlations between principal components index of each period and carcass traits such as carcass weight(0.539∼0.755), average daily gain(0.256∼0.564), backfat thickness(0.227∼0.280), and eye muscle area(0.187∼0.344). The correlation with yield grade index(-0.246∼-0.110), however, was negative. The correlation with marbling score(0.066∼0.099) was low or statistically insignificant. According to principal component indexes of the second, third, and fourth components, the correlations with the carcass traits were various. There were no large differences between the correlations of the single body measurement trait with the carcass traits and the correlations of the first principal component indexes with the carcass traits.

Ion scattering spectroscopy study of the Si(001)c(4x4)-C surface reconstruction

Park J. Y.,Chae K. H.,Choi D. S.,Kim J. Y.,Kim S. S.,Seo J. H.,Whang C. N. 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3

Reconstructed Si(001)c(4 4)-C surface has been studied by coaxial impact collision ion scattering spectroscopy (CAICISS). When 100L ethylene (C2H4) was exposed on Si(001)-(2 1) surface at 700 C, Si(001) dimer structures were changed by induced carbon (C) atoms. The experimental CAICISS spectra and simulation results reveal that the reconstructed Si(001)c(4 4)-C surface shows good agreement with the missing dimer model, rather than the Si-C heterodimer model, and adsorbed C atoms in uence only the reconstructed vertical plane of Si(001) surface. On comparing the azimuthal-scan curves for 100L C/Si(001) with those for clean Si(001), it can be suggested that C atoms occupy the fourth subsurface layer of Si(001) directly below the HB (bridge) site. These results are new evidence supporting the previous studies based on the C incorporation into Si(001) surface with missing dimers and the substitution of the fourth Si layers.

Protein Profile in Corpus Luteum during Pregnancy in Korean Native Cows

Chung, H.J.,Kim, K.W.,Han, D.W.,Lee, H.C.,Yang, B.C.,Chung, H.K.,Shim, M.R.,Choi, M.S.,Jo, E.B.,Jo, Y.M.,Oh, M.Y.,Jo, S.J.,Hong, S.K.,Park, J.K.,Chang, W.K. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.11

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.