Site-specific mutagenesis of yeast 2-Cys peroxiredoxin improves heat or oxidative stress tolerance by enhancing its chaperone or peroxidase function

Hong, S. H.,Lee, S. S.,Chung, J. M.,Jung, H. s.,Singh, S.,Mondal, S.,Jang, H. H.,Cho, J. Y.,Bae, H. J.,Chung, B. Y. Springer Science + Business Media 2017 Protoplasma Vol.254 No.1

<P>Yeast peroxiredoxin II (yPrxII) is an antioxidant enzyme that plays a protective role against the damage caused by reactive oxygen species (ROS) in Saccharomyces cerevisiae. This enzyme consists of 196 amino acids containing 2-Cys Prx with highly conserved two active cysteine residues at positions 48 and 171. The yPrxII has dual enzymatic functions as a peroxidase and molecular chaperone. To understand the effect of additional cysteine residues on dual functions of yPrxII, S79C-yPrxII and S109C-yPrxII, the substitution of Ser with Cys residue at 79 and 109 positions, respectively, was generated. S109C-yPrxII and S79C-yPrxII showed 3.7- and 2.7-fold higher chaperone and peroxidase activity, respectively, than the wild type (WT). The improvement in enzyme activity was found to be closely associated with structural changes in proteins. S109C-yPrxII had increased beta-sheet in its secondary structure and formed high-molecular-weight (HMW) as well as low-molecular-weight (LMW) complexes, but S79C-yPrxII formed only LMW complexes. HMW complexes predominantly exhibited a chaperone function, and LMW complexes showed a peroxidase function. In addition, transgenic yeast cells over-expressing Cys-substituted yPrxII showed greater tolerance against heat and oxidative stress compared to WT-yPrxII.</P>

Strategy for enhancing the solar-driven water splitting performance of TiO₂ nanorod arrays with thin Zn(O,S) passivated layer by atomic layer deposition

Shin, S.W.,Suryawanshi, M.P.,Hong, H.K.,Yun, G.,Lim, D.,Heo, J.,Kang, S.H.,Kim, J.H. Pergamon Press 2016 ELECTROCHIMICA ACTA Vol.219 No.-

An array of one dimensional (1D) TiO<SUB>2</SUB> nanorods (TONRs) has been regarded as an attractive candidate for electrochemical energy conversion and as storage device due to its large surface area, effiective light scattering, and undisturbed charge transport pathway. However, the high defect/trap densities on surface of the nanostructured morphology and architecture may generally hinder the performance enhancement by providing electron-hole recombination sites. Hence, the surface passivation of nanoarchitectures based photoelectrodes has recently received much attention as an effective strategy to enhance the charge-separation and charge-transfer processes in photoelectrochemical (PEC) water splitting devices. In particular, a coating layer with narrowing band gap materials can promote enhanced light harvesting in the UV-vis region as well as surface passivation, directly supplying a driving force for charge separation and charge transfer due to band alignment. In this paper, the surface of TONRs were passivated by 10 and 30nm thick Zn(O,S) layers with a relatively narrow band gap using an atomic layer deposition technique to modulate the thickness exactly. The 10nm Zn(O,S)/TONR array exhibits a significantly enhanced photocurrent density (J<SUB>sc</SUB>) of 5.94mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an incident photon-to-electron conversion efficiency (IPCE) of 49% at 374nm compared with that of TONR arrays (J<SUB>sc</SUB> of 1.99mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an IPCE of 20% at 380nm). However, the PEC performance is worse in the 30nm Zn(O,S)/TONR arrays, showing a J<SUB>sc</SUB> of 3.09mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an IPCE of 29% at 374nm. To clearly demonstrate these PEC behaviors, the TONR and Zn(O,S)/TONR arrays were characterized by electrochemical impedance spectroscopy (EIS), open circuit voltage decay (OCV) measurement, and X-ray photoelectron spectroscopy (XPS). The above mentioned characterizations indicate that the enhanced PEC performance of the 10nm Zn(O,S)/TONR array resulted from the (i) increased light harvesting in the UV-vis region, (ii) lower charge transfer resistance and (iii) high value of valence band offset (VBO, -1.44eV) and conduction band offset (CBO, -1.2eV) than those of the TONR. However, the deterioration of J<SUB>sc</SUB> in the 30nm Zn(O,S)/TONR array is attributed to the negative value of VBO (-0.13eV) and positive value of CBO (+0.27eV), as well as the higher charge transfer resistance to the electrolyte than that of the TONR arrays, despite of the improved light absorption in the visible region. The photocurrent densities of 10nm Zn(O,S)/TONR and 30nm Zn(O,S)/TONR photocathodes decay to 4.718mA/cm<SUP>2</SUP> (5.90mA/cm<SUP>2</SUP> at 0min) and 2.212mA/cm<SUP>2</SUP> (3.03mA/cm<SUP>2</SUP> at 0min) after 90min, respectively, they retain of about~80% and 70% of its original values. These experimental results and discussions not only provide the physical insights into the surface passivation effect and band alignment but also can open a promising route to design the thin passivation layer having the narrowing band gap energy (1.0eV~2.5eV) on the 1D TiO<SUB>2</SUB> nanostructure for further enhanced performance and realization of a TiO<SUB>2</SUB> based PEC system.

Prediction of stone-free status and complication rates after tubeless percutaneous nephrolithotomy: a comparative and retrospective study using three stone-scoring systems and preoperative parameters

Choi, S. W.,Bae, W. J.,Ha, U. S.,Hong, S. H.,Lee, J. Y.,Kim, S. W.,Cho, H. J. Springer Science + Business Media 2017 World journal of urology Vol.35 No.3

<P>To investigate the factors predictive of surgical outcomes of tubeless percutaneous nephrolithotomy (TPCNL) and to compare the predictability and accuracy of the Guy's stone score, S.T.O.N.E. nephrolithometry, and CROES nomogram. We reviewed retrospectively the surgical outcomes recorded consecutively and imaging data of preoperative computed tomography scans of 141 patients who had undergone TPCNL from June 2012 to October 2015. Guy's, S.T.O.N.E., and CROES stone-scoring systems (SSSs) and other prognostic factors were assessed using univariate and multivariate statistical analyses. The initial stone-free and complication rates after TPCNL were 78.7 (111/141) and 17.0 % (24/141). On univariate analysis, all three scoring systems were identified as significant factors in terms of stone-free rate (SFR). The multivariate logistic regression analysis showed that the Guy's stone score and stone burden 385 mm(2) had significant correlations with stone-free status [odds ratios (OR) = 3.220, p = 0.001 and OR = 6.451, p = 0.002, respectively]. Guy's stone score (OR = 1.879, p = 0.013) was an independent risk factor for the development of complications. The area under the receiver operating characteristic (ROC) curves for the Guy's, S.T.O.N.E., and CROES SSSs and stone burden showed good results (0.821, 0.816, 0.820, and 0.800, respectively). Pairwise comparison of ROC curves showed that there was no significant difference between each final score and stone burden. Of the three scoring systems, Guy's stone score was the only significant predictive factor for SFR and complication rates after TPCNL in the multivariate logistic regression analysis. Stone burden was significantly associated with a postoperative stone-free status (SFS).</P>

Complete chloroplast genome sequences of Solanum commersonii and its application to chloroplast genotype in somatic hybrids with Solanum tuberosum

Cho, K. S.,Cheon, K. S.,Hong, S. Y.,Cho, J. H.,Im, J. S.,Mekapogu, M.,Yu, Y. S.,Park, T. H. Springer International 2016 Plant cell reports Vol. No.

<P>Chloroplast genome of Solanum commersonii and S olanum tuberosum were completely sequenced, and Indel markers were successfully applied to distinguish chlorotypes demonstrating the chloroplast genome was randomly distributed during protoplast fusion. Somatic hybridization has been widely employed for the introgression of resistance to several diseases from wild Solanum species to overcome sexual barriers in potato breeding. Solanum commersonii is a major resource used as a parent line in somatic hybridization to improve bacterial wilt resistance in interspecies transfer to cultivated potato (S. tuberosum). Here, we sequenced the complete chloroplast genomes of Lz3.2 (S. commersonii) and S. tuberosum (PT56), which were used to develop fusion products, then compared them with those of five members of the Solanaceae family, S. tuberosum, Capsicum annum, S. lycopersicum, S. bulbocastanum and S. nigrum and Coffea arabica as an out-group. We then developed Indel markers for application in chloroplast genotyping. The complete chloroplast genome of Lz3.2 is composed of 155,525 bp, which is larger than the PT56 genome with 155,296 bp. Gene content, order and orientation of the S. commersonii chloroplast genome were highly conserved with those of other Solanaceae species, and the phylogenetic tree revealed that S. commersonii is located within the same node of S. tuberosum. However, sequence alignment revealed nine Indels between S. commersonii and S. tuberosum in their chloroplast genomes, allowing two Indel markers to be developed. The markers could distinguish the two species and were successfully applied to chloroplast genotyping (chlorotype) in somatic hybrids and their progenies. The results obtained in this study confirmed the random distribution of the chloroplast genome during protoplast fusion and its maternal inheritance and can be applied to select proper plastid genotypes in potato breeding program.</P>

Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis

Yu, K‐,H.,Hong, K‐,S.,Lee, B‐,C.,Oh, M‐,S.,Cho, Y‐,J.,Koo, J‐,S.,Park, J‐,M.,Bae, H‐,J.,Han, M‐,K.,Ju, Y‐,S.,Kang, D‐,W.,Appelros, P. Blackwell Publishing Ltd 2011 Acta neurologica Scandinavica Vol.123 No.5

<P>Yu K‐H, Hong K‐S, Lee B‐C, Oh M‐S, Cho Y‐J, Koo J‐S, Park J‐M, Bae H‐J, Han M‐K, Ju Y‐S, Kang D‐W, Appelros P, Norrving B, Terent A. Comparison of 90‐day case‐fatality after ischemic stroke between two different stroke outcome registries using propensity score matching analysis. 
Acta Neurol Scand: 2011: 123: 325–331. 
© 2010 John Wiley & Sons A/S.</P><P><B>Background – </B> It has not been clarified whether the disparity in ischemic stroke outcome between populations is caused by ethnic and geographic differences or by variations in case mix. Propensity score matching (PSM) analysis can overcome some analytical problems but is rarely used in stroke outcome research. This study was to compare the ischemic stroke case‐fatality between two PSM cohorts of Sweden and Korea.</P><P><B>Methods – </B> Prognostic variables related to baseline characteristics and stroke care were included in our PSM model. Then, we selected 7675 Swedish and 1220 Korean patients with ischemic stroke from each stroke registers and performed one‐to‐one matching based on propensity scores of each patient.</P><P><B>Results – </B> After PSM, all measured variables were well balanced in 1163 matched subjects, and the 90‐day case‐fatality was identical 6.2% (HR 0.997, 95%CI 0.905–1.099) in Sweden and Korea.</P><P><B>Conclusions – </B> No difference is found in the 90‐day case‐fatality in propensity score‐matched Swedish and Korean patients with ischemic stroke.</P>

Production of soluble truncated spike protein of porcine epidemic diarrhea virus from inclusion bodies of Escherichia coli through refolding

Piao, D.C.,Lee, Y.S.,Bok, J.D.,Cho, C.S.,Hong, Z.S.,Kang, S.K.,Choi, Y.J. Academic Press 2016 Protein expression and purification Vol.126 No.-

The emergence of highly pathogenic variant porcine epidemic diarrhea virus (PEDV) strains, from 2013 to 2014, in North American and Asian countries have greatly threatened global swine industry. Therefore, development of effective vaccines against PEDV variant strains is urgently needed. Recently, it has been reported that the N-terminal domain (NTD) of S1 domain of PEDV spike protein is responsible for binding to the 5-N-acetylneuraminic acid (Neu5Ac), a possible sugar co-receptor. Therefore, the NTD of S1 domain could be an attractive target for the development of subunit vaccines. In this study, the NTD spanning amino acid residues 25-229 (S25-229) of S1 domain of PEDV variant strain was expressed in Escherichia coli BL21 (DE3) in the form of inclusion bodies (IBs). S25-229 IBs were solubilized in 20 mM sodium acetate (pH 4.5) buffer containing 8 M urea and 1 mM dithiothreitol with 95% yield. Solubilized S25-229 IBs were refolded by 10-fold flash dilution and purified by one-step cation exchange chromatography with >95% purity and 20% yield. The CD spectrum of S25-229 showed the characteristic pattern of alpha helical structure. In an indirect ELISA, purified S25-229 showed strong reactivity with mouse anti-PEDV sera. In addition, immunization of mice with 20 μg of purified S25-229 elicited highly potent serum IgG titers. Finally, mouse antisera against S25-229 showed immune reactivity with native PEDV S protein in an immunofluorescence assay. These results suggest that purified S25-229 may have potential to be used as a subunit vaccine against PEDV variant strains.

Characteristics of FAM-Z01 compared to silica gels in the performance of an adsorption bed

Hong, S.W.,Ahn, S.H.,Chung, J.D.,Bae, K.J.,Cha, D.A.,Kwon, O.K. Pergamon 2016 Applied thermal engineering Vol. No.

This paper investigates the characteristics of ferroaluminophosphate (FAM-Z01) compared to various types of conventional silica gels in the performance of an adsorption bed. FAM-Z01 has high potential to replace silica gel due to some key advantages, including a low heating temperature and high adsorption rate resulting from its S-shaped isotherm. We conducted a performance simulation on a fin-tube type adsorption bed with FAM-Z01/water and silica gel/water working pairs and compared the results in terms of coefficient of performance (COP) and specific cooling power (SCP). In the partial pressure range of typical operating condition for silica gels, there was no advantage with FAM-Z01. However, in the partial pressure range of 0.14<P/P<SUB>0</SUB><0.29, which corresponds to a lower evaporation temperature (15<SUP>o</SUP>C→10<SUP>o</SUP>C) and lower heating temperature (80<SUP>o</SUP>C→70<SUP>o</SUP>C) compared to the typical operating condition for silica gels, the COP of FAM-Z01 was almost similar (3.72% decreased) to that of Type-RD silica gel, while the SCP was significantly increased by 35.0%. This indicates that without a change of system efficiency, FAM-Z01/water has a high cooling capacity with small size as compared to Type-RD silica gel/water. This confirms that the adsorbent FAM-Z01 has a high potential to address one of the adsorption chiller's disadvantages, i.e., system size.

Lipoteichoic acid of Streptococcus mutans interacts with Toll-like receptor 2 through the lipid moiety for induction of inflammatory mediators in murine macrophages

Hong, S.W.,Baik, J.E.,Kang, S.S.,Yun, C.H.,Seo, D.G.,Han, S.H. Pergamon Press 2014 Molecular immunology Vol.57 No.2

Streptococcus mutans is a pathogenic Gram-positive bacterium that is closely associated with dental caries and subsequent pulpal inflammation. Although lipoteichoic acid (LTA) is considered a major virulence factor of Gram-positive bacteria, little is known about the innate immunity to S. mutans LTA. In this study, we purified LTA from S. mutans (Sm.LTA) through n-butanol extraction, hydrophobic interaction column chromatography, and ion-exchange column chromatography to investigate its immunological properties using murine macrophages. The Sm.LTA preparation had no detectable contamination with endotoxins, proteins, or nucleic acids. Upon exposure to Sm.LTA, the murine macrophage cell-line RAW 264.7 cells produced TNF-α and nitric oxide (NO) in a dose-dependent manner. Sm.LTA preferentially bound to and activated CHO/CD14/TLR2 cells rather than CHO/CD14/TLR4 cells, which are stable transfectants expressing CD14 and TLR2 or CD14 and TLR4, respectively. Sm.LTA could not induce TNF-α or NO production in macrophages derived from TLR2-deficient mice whereas it dose-dependently induced those inflammatory mediators in wild-type macrophages. TLR2-dependent induction of NO by Sm.LTA was also confirmed in RAW 264.7 cells using specific antibodies blocking TLR2. Furthermore, Sm.LTA deacylated by alkaline hydrolysis neither stimulated TLR2 nor induced TNF-α or NO production, suggesting that Sm.LTA lipid moieties are crucial for the immuno-stimulatory activity of Sm.LTA. Unlike Staphylococcus aureus LTA, which has potent immuno-stimulating activity, Sm.LTA showed a modest induction of NO production comparable to LTAs of other oral bacteria Enterococcus faecalis and Lactobacillus plantarum. In conclusion, our results suggest that the Sm.LTA interacts with TLR2 through the lipid moiety for the induction of inflammatory mediators in macrophages.

Experimental Approach to Explosive Nucloeosynthesis with RI Beams

S. Kubono,Y. Yamaguchi,G. Amadio,S. Hayakawa,Y. Wakabayashi,Y. Kurihara,J. J. He,A. Saito,H. Fujikawa,Le Hong Khiem,M. Niikura,T. Teranishi,N. Iwasa,S. Kato,S. Nishimura,C. S. Lee,Y. K. Kwon,I. S. Hah 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

Experimental efforts to investigate stellar reactions under high-temperature and high density conditions have been made as a major program using the RI beams from the Center for Nuclear Study (CNS) low-energy in-flight RI beam separator (CRIB) at University of Tokyo in order to understand the evolution of the universe, as well as various stellar phenomena. Specically, two subjects of hydrogen burning are discussed here. One is a reaction study of the pp-chain and the second is of the explosive hydrogen burning, the rp-process. Some s-wave resonances have been identified by the thick target method in the crucial reaction processes in the hydrogen burning. The resonant scattering with the thick target method also succeeded in identifying inelastic resonant scattering, giving proton widths for the first excited state of the target nucleus. This provided very efficiently the reaction rate estimate for the process under high-temperature equilibrium conditions. Possibilities of the CRIB facility in near future are also briey discussed. Experimental efforts to investigate stellar reactions under high-temperature and high density conditions have been made as a major program using the RI beams from the Center for Nuclear Study (CNS) low-energy in-flight RI beam separator (CRIB) at University of Tokyo in order to understand the evolution of the universe, as well as various stellar phenomena. Specically, two subjects of hydrogen burning are discussed here. One is a reaction study of the pp-chain and the second is of the explosive hydrogen burning, the rp-process. Some s-wave resonances have been identified by the thick target method in the crucial reaction processes in the hydrogen burning. The resonant scattering with the thick target method also succeeded in identifying inelastic resonant scattering, giving proton widths for the first excited state of the target nucleus. This provided very efficiently the reaction rate estimate for the process under high-temperature equilibrium conditions. Possibilities of the CRIB facility in near future are also briey discussed.

Ti/Cu-Cr/S20C의 계면특성 및 기계적 거동

하종수(J. S. Ha),김인규(I. K. Kim),김형섭(H. S. Kim),홍순익(S. I. Hong) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10