• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.68-74
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• 1999

The optimum conditions for selective .elimination of salt from tuna boiled extract (TBE) by electrodialysis were determined. The desalination conditions of TBE were determined at various pH's, concentrations and volumes of TBE. The ion-exchange membrane with a molecular weight cut off 100Da was used for desalting of TBE. The desalination times on $1\%$ and $10\%$ of TBE concentrations were 40 min and 240 min, respectively. The electrodialysis process could removed above $95\%$ of the initial salt content in $1\%$ and $10\%$ of TBE concentrations. The desalination of TBE at pH 4.0 was $14\%$ higher than that at pH 9.0 The amount of water transferred by the electrodialysis was determined. The electrodialysis process could remove above $90\%$ of the initial salt content in $5\%$ TBE for 80 min. The initial volume and the permeate did not have significant effects on desalination time and ratio. The key parameters for the desalination of TBE were pH and concentration of TBA.

• Journal of Chest Surgery
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• v.27 no.3
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• pp.177-186
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• 1994

Pentastarch is a hydroxyethyl starch similar to hetastarch, but lower average molecular weight and fewer hydroxyethyl groups which result in enhanced enzymatic hydrolysis and faster renal elimination.This report was performed to compare the clinical efficacy and safety of 10 % pentastarch[Pentaspan , group I] for plasma volume expansion after open heart surgery with that of 5% albumin[Plasmanate, group II]. There were no statistically significant differences between the group I [n=18] and group II [n:19] in the preoperative parameters [age, sex, body weight] and operative parameters[bypass time, aorta cross clamping time]. During the first 24 hours after arrival of the patient in the surgical intensive care unit, colloid solution [500--1000 ml] was infused to maintain left atrial pressure of more than 8 mmHg, or cardiac index of 2.0 L/min/M2 of more. In results, there were 3 complications of hypotension immediately after infusion of 5 % albumin solution and 2 among the 3 patients were excluded for the study. However there was no complication after infusion of 10 % pentastarch solution. Hemodynamic responses to infusion was similar for both groups, although in group I a greater increase in both left atrial pressure[mean 1.8 versus 0.7 mmHg, p< 0.05] and right atrial pressure [mean 2.2 versus 1.7 mmHg, p < 0.05] was observed during infusion of the first 500 ml. There were no significant differences in any of the measured respiratory parameters[PaO2, intrapulmonary shunt, and effective lung compliance]. Homodilution with colloid significantly reduced hemoglobin [mean 1.2 versus 0.8 gm/dl], and serum protein and albumin level[total protein;4.8$\pm$ 0.5 versus 5.2 $\pm$0.5 gm/dl, p < 0.05: albumin: 3.2 $\pm$0.4 versus 3.6 $\pm$0.6 gm/dl, p < 0.05] by 6:00 AM on 1 day postoperatively, however there were no significant differences on 7 day postoperatively. The mean serum colloid osmotic pressure and osmolarity was similar in both group.There were no abnormal findings of liver function and kidney function in all the patients. There were no significant between-group differences in bleeding time, platelets, prothrombin time, activated partial thromboplastin time and amount of chest tube output measured on 1st and 7th postoperative day. These findings demonstrated that 10% pentastarch is more effective and safe for plasma volume expension than 5 % albumin solution with no adverse effects on coagulation. Also 10 % pentastarch is less expensive than 5 % albumin and it would appeare to be a reasonable first choice for plasma volume expansion.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.1-8
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• 2017

Measles virus is a highly contagious, exanthematic virus, preventable by the use of an effective live-attenuated vaccine. However, measles virus remains endemic in many area of the world causing nearly 200,000 deaths per year and still a major cause of child mortality, mostly in developing countries. In March 2014, Republic of Korea was certified as a 'national measles elimination' by the WHO as a result of a high-quality case-based surveillance system and population immunity, which was achieved by a high vaccination rate (>95.0% since 1996). But, since the beginning of 2014, the Gyeonggi province has experienced a resurgence of measles cases. In this study, we investigated the characteristics of measles viruses isolated from confirmed measles in Gyeonggi province during January 1, 2014 ~ July 31, 2014, 60 isolates were obtained from 72 confirmed measles specimens. Genotypic distributions and genetic diversities of isolated measles virus were analyzed by sequencing of nucleoprotein (N) gene. 58 (96.7%) imported cases were identified. The predominant genotype was B3, which reflects the circulating measles virus in adjacent countries. The sequences of nucleoprotein (N) gene of isolated MeV were showed that the strains characterized showed the highest degree of identity (99%) with the Philippine related strains in 2013-2014. Therefore, infected traveler returning from the Philippines transmitted secondary infection in Korea.

• Journal of Life Science
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• v.18 no.4
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• pp.461-466
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• 2008

Transforming growth $factor-{\beta}$ ($TGF-{\beta}$)-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Gadd45b has been known to participate in $TGF-{\beta}-induced$ apoptosis by the activation of p38 kinase. In this report, we show that Gadd45b is an immediate-early response gene for $TGF-{\beta}$ during apoptosis in EpH4 cells. To elucidate the molecular mechanism of $TGF-{\beta}-induced$ Gadd45b gene expression, we cloned the 5'-flanking region of the mouse Gadd45b gene. When transfected into EpH4 cells, this 5'-flanking region conferred promoter activity and inducibility by $TGF-{\beta}$. Deletion analyses demonstrated that the minimal promoter activity was detected in the proximal region 220 bp upstream of the transcription initiation site. We also found that the proximal Gadd45b promoter is activated by $TGF-{\beta}$ through the action of Smad2, Smad3, and Smad4. Finally, we show that the expression of Gadd45b gene by $TGF-{\beta}$ is suppressed in EpRas cells in which $TGF-{\beta}$ could not induce apoptosis, suggesting that Gadd45b may be a crucial target for $TGF-{\beta}-induced$ apoptosis in EpH4 cells.

• Applied Biological Chemistry
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• v.22 no.4
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• pp.198-209
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• 1979

L-Tyrosine, 2-chloro-L-tyrosine, 2-bromo-L-tyrosine, and 2-iodo-L-tyrosine were synthesized by ${\beta}-tyrosinase$ obtained from cells of Escherichia intermedia A-21, through the reversal of the ${\alpha},{\beta}-elimination$ reaction, and their molecular structures were analyzed by element analysis, NMR spectroscopy, mass spectrometry and IR spectroscopy. Rates of synthesis and hydrolysis of halogenated tyrosines by ${\beta}-tyrosinase$, inhibition of the enzyme activity by halogenated phenols, and effects of addition of m-bromophenol on the synthesis of 2-bromotyrosine were determined. The results obtained were as follows: 1) In the synthesis of halogenated tyrosines, the yield of 2-chlorotyrosine from m-chlorophenol were approximately 15 per cent, that of 2-bromotyrosine from m-bromophenol 13.8 per cent, and that of 2-iodotyrosine from m-iodophenol 9.8 per cent. 2) Rate of synthesis of halogenated tyrosines by ${\beta}-tyrosinase$ was slower than that of tyrosine and the rates were decreased in the order of chlorine, bromine and iodine, that is, by increasing the atomic radius. Relative rate of 2-chlorotyrosine synthesis was determined to be 28.2, that of 2-bromotyrosine to be 8.13, and that of 2-iodotyrosine to be 0.98, respectively, against 100 of tyrosine. However 3-iodotyrosine was not synthesized by the enzyme. 3) The relative rate of 2-chlorotyrosine hydrolysis by ${\beta}-tyrosinase$ was 70.7, that of 2-bromotyrosine was 39.0, and that of 2-iodotyrosine was 12.6 against 100 of tyrosine, respectively. The rate of hydrolysis appeared to be decreased in the order of chlorine, bromine and iodine, that is, by increasing the atomic radius or by decreasing the electronegativity. But 3-iodotyrosine was not hydrolyzed by the enzyme. 4) The activity of ${\beta}-tyrosinase$ was inhibited by phenol markedly. Of the halogenated phenols, o-, or m-chlorophenol and o-bromophenol gave marked inhibition on the enzyme action, however inhibition by iodophenol was not strong. Plotting by Lineweaver-Burk method, a mixed-type inhibition by m-chlorophenol was observed and its Ki value was found to be $5.46{\times}10^{-4}M$. 5) During the synthesizing reaction of 2-bromotyrosine by the enzyme, sequential addition of substrate which was m-bromophenol with time intervals and in a small amount resulted in better yield of the product. 6) The halogenated tyrosines which were produced by ${\beta}-tyrosinase$ from pyruvate, ammonia and m-halogenated phenols were analysed to determine their molecular structures by element analysis, NMR spectroscopy, mass spectrometry, and IR spectroscopy. The result indicated that they were 2-chloro-L-tyrosine, 2-bromo-L-tyrosine, and 2-iodo-L-tyrosine, respectively.