Involvement of S6K1 in mitochondria function and structure in HeLa cells

Park, J.,Tran, Q.,Mun, K.,Masuda, K.,Kwon, S.H.,Kim, S.H.,Kim, D.H.,Thomas, G.,Park, J. Pergamon Press ; Elsevier Science Ltd 2016 Cellular signalling Vol.28 No.12

The major biological function of mitochondria is to generate cellular energy through oxidative phosphorylation. Apart from cellular respiration, mitochondria also play a key role in signaling processes, including aging and cancer metabolism. It has been shown that S6K1-knockout mice are resistant to obesity due to enhanced beta-oxidation, with an increased number of large mitochondria. Therefore, in this report, the possible involvement of S6K1 in regulating mitochondria dynamics and function has been investigated in stable lenti-shS6K1-HeLa cells. Interestingly, S6K1-stably depleted HeLa cells showed phenotypical changes in mitochondria morphology. This observation was further confirmed by detailed image analysis of mitochondria shape. Corresponding molecular changes were also observed in these cells, such as the induction of mitochondrial fission proteins (Drp1 and Fis1). Oxygen consumption is elevated in S6K1-depeleted HeLa cells and FL5.12 cells. In addition, S6K1 depletion leads to enhancement of ATP production in cytoplasm and mitochondria. However, the relative ratio of mitochondrial ATP to cytoplasmic ATP is actually decreased in lenti-shS6K1-HeLa cells compared to control cells. Lastly, induction of mitophagy was found in lenti-shS6K1-HeLa cells with corresponding changes of mitochondria shape on electron microscope analysis. Taken together, our results indicate that S6K1 is involved in the regulation of mitochondria morphology and function in HeLa cells. This study will provide novel insights into S6K1 function in mitochondria-mediated cellular signaling.

1H Nuclear Magnetic Resonance study of Ferroelectric (NH4)3H(SO4)2

S. H. Choi,K. S. Han,S. K. Kwon,S. K. Nam,H. H. Choi,Moohee Lee,Ae Ran Lim 한국자기공명학회 2007 Journal of the Korean Magnetic Resonance Society Vol.11 No.2

1H nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal (NH4)3H(SO4)2. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the 1H NMR MAS spectrum at 340 K. As temperature decreases, the 1H NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of T1 for ammonium and hydrogen-bond protons are similar in the whole range of temperature. T1 of 1H NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then T1 shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and T1 clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

S–N Fatigue and Fatigue Crack Propagation Behaviors of X80 Steel at Room and Low Temperatures

Jung, D. H.,Kwon, J. K.,Woo, N. S.,Kim, Y. J.,Goto, M.,Kim, S. Springer Science + Business Media 2014 Metallurgical and Materials Transactions A - Physi Vol.45 No.2

<P>In the present study, the S-N fatigue and the fatigue crack propagation (FCP) behaviors of American Petroleum Institute X80 steel were examined in the different locations of the base metal (BM), weld metal (WM), and heat-affected zone (HAZ) at 298 K, 223 K, and 193 K (25 degrees C, 50 degrees C, and 80 degrees C). The resistance to S-N fatigue of X80 BM specimen increased greatly with decreasing temperature from 298 K to 193 K (25 degrees C to -80 degrees C) and showed a strong dependency on the flow strength (1/2(yield strength + tensile strength)). The FCP rates of X80 BM specimen were substantially reduced with decreasing temperature from 298 K to 223 K (25 degrees C to 50 degrees C) over the entire Delta K regime, while further reduction in FCP rates was not significant with temperature from 223 K to 193 K (-50 degrees C to -80 degrees C). The FCP rates of the X80 BM and the WM specimens were comparable with each other, while the HAZ specimen showed slightly better FCP resistance than the BM and the WM specimens over the entire Delta K regime at 298 K (25 degrees C). Despite the varying microstructural characteristics of each weld location, the residual stress appeared to be a controlling factor to determine the FCP behavior. The FCP behaviors of high strength X80 steel were discussed based on the microstructural and the fractographic observations. (C) The Minerals, Metals & Materials Society and ASM International 2013</P>

1H NMR Measurements of the Phase Transition of (NH₄)₃H(SO₄)₂ Single Crystals

S. H. Choi,Moohee Lee,Ae Ran Lim,K. S. Han,S. K. Kwon,S. K. Nam 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2

$^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K. $^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K.

화학적 거세 및 갑상선 기능조절이 닭의 산육성 증진에 미치는 효과에 관한 연구

이규승,김관영,권순기 忠南大學校 1971 論文集 Vol.10 No.-

This experiment was conducted to improve the meat production and quality of cockerels by controling the function of thyroid and gonad with the hormone preparations. Three weeks old 180 Rhode island red cockerels were divided into six group : iodocasein treatment group, tapazol treatment group, D.E.S. treatment group, D.E.S.+iodocasein treatment group, D.E.S.+tapazol treatment group and control group. Each group was then divided into two groups of 4 weeks and 8 weeks after treatment, arranging the cockerels 15 each. Iodocasein of 0.25 per cent of the basal ration and tapazol in dose of 0.3 ㎎ per Kg of body weight were administered with the basal ration, and 0.75 ㎎ of D.E.S. was implanted subcutaneously at the head. Body weight was measured weekly to investigate the growth rate and daily gain. Sacrifice was done at the certain days after treatment, and carcass percentage and organ weight were observed. Histological observation on thyroid and gonad was conducted at the same time. The results obtained areas follows; 1. The body weight of D. E. S. group, Tap. group and D. E. S. +Tap. group at the end of experimental period were 1452.37±17.61g and 1473.53±16.18g respectively, showing the increasing significance with P<0.05 as compared with 1305.93±21.67g of control group. Iodo. group and D.E.S.+Iodo. group were lighter than control group, but no significance was recognized. 2. Daily gain and carcass percentage were changed as a similar tendency, showing the significance with P<0.05 after 4 weeks and no significance after 8 weeks. Generally high value was obtained in the group treated with D.E.S. and tapazol. 3. Among the meat compositions any marked difference was not recognized in moisture and crude ash cntents of the experimental groups. Crude protein contents were comparatively more in control group (19.87%) than in treatment groups. As compared with 3.39% of control group, crude fat contents of Tap. grop, D. E. S. group anud D. E. S. +Tap. group were 4.44%, 4.22% and 5.35% respectively. 4. Improved effects on feed convertion rate were obtained in the groups treated with D.E.S. and tapazol. D.E.S.+Tap. group was best : 2.61 on the mean. 5. Comb and wattle weights were changed as a similar tendency, showing the significance with p<0.01 after 4 and 8 weeks. Those of all treatment groups were lighter than of control group, particularly in the groups treated with D.E.S. they were atrophied extremely. 6. Generally weights of head, heart, spleen, gizzard and liver were in proportion to body weight. 7. Whole viscera weight showed the significance with p<0.01 among the treatment groups after 4 and 8 weeks. Those of the groups treated with tapazol and D.E.S. were heavier than of control group. 8. Cloacal thymus weight showed the significance with p<0.05. That of control group was heaviest, being heavier after 4 weeks than after 8 weeks. Meat production and quality cockerels was improved successively by decreasing more or less the function of thyroid and gonad with tapazol and D.E.S. treatment. Only use of tapazol or D.E.S. was fairly effective. Because the iodocasein administration caused the growth restraint and derease of fats, it was worthless for practical application.

[ $^1H$ ] Nuclear Magnetic Resonance Study of Ferroelectric $(NH_4)_3H(SO_4)_2$

Choi, S.H.,Han, K.S.,Kwon, S.K.,Nam, S.K.,Choi, H.H.,Lee, Moo-Hee,Lim, Ae-Ran Korean Magnetic Resonance Society 2007 Journal of the Korean Magnetic Resonance Society Vol.11 No.2

[ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

The microRNA miR-124 inhibits vascular smooth muscle cell proliferation by targeting S100 calcium-binding protein A4 (S100A4)

Choe, N.,Kwon, D. H.,Shin, S.,Kim, Y. S.,Kim, Y. K.,Kim, J.,Ahn, Y.,Eom, G. H.,Kook, H. Elsevier Science B.V., Amsterdam. 2017 FEBS letters Vol.591 No.7

<P>S100 calcium-binding protein A4 (S100A4) induces proliferation and migration of vascular smooth muscle cells (VSMCs). We aimed to find the microRNA regulating S100A4 expression. S100A4 transcripts are abruptly increased in the acute phase of carotid arterial injury 1 day later (at day 1) but gradually decreases at days 7 and 14. Bioinformatics analysis reveals that miR-124 targets S100A4. VSMC survival is attenuated by miR-124 mimic but increased by miR-124 inhibitor. miR-124 decreases immediately after carotid arterial injury but dramatically increases at days 7 and 14. miR-124 inhibitor-induced cell proliferation is blocked by S100A4 siRNA, whereas miR-124-induced cell death is recovered by S100A4. Our findings suggest that miR-124 is a novel regulator of VSMC proliferation and may play a role in the development of neointimal proliferation.</P>

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.

Modeling and simulation of HTS cables for scattering parameter analysis

Bang, S.S.,Lee, G.S.,Kwon, G.Y.,Lee, Y.H.,Chang, S.J.,Lee, C.K.,Sohn, S.,Park, K.,Shin, Y.J. North-Holland 2016 Physica. C, Superconductivity Vol.530 No.-

<P>Most of modeling and simulation of high temperature superconducting (HTS) cables are inadequate for high frequency analysis since focus of the simulation's frequency is fundamental frequency of the power grid, which does not reflect transient characteristic. However, high frequency analysis is essential process to research the HTS cables transient for protection and diagnosis of the HTS cables. Thus, this paper proposes a new approach for modeling and simulation of HTS cables to derive the scattering parameter (S-parameter), an effective high frequency analysis, for transient wave propagation characteristics in high frequency range. The parameters sweeping method is used to validate the simulation results to the measured data given by a network analyzer (NA). This paper also presents the effects of the cable-to-NA connector in order to minimize the error between the simulated and the measured data under ambient and superconductive conditions. Based on the proposed modeling and simulation technique, S-parameters of long-distance HTS cables can be accurately derived in wide range of frequency. The results of proposed modeling and simulation can yield the characteristics of the HTS cables and will contribute to analyze the HTS cables. (C) 2016 Elsevier B.V. All rights reserved.</P>

Electrochemical analysis on the growth of oxide formed on stainless steels in molten carbonate at 650 ^oC

Ahn, S.,Oh, K.,Kim, M.,Youn, J.,Jo, K.,Kim, K.,Kwon, H. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.23

The oxide growth on stainless steel (SS) 310S and 316L, used as a cathode current collector material of molten carbonate fuel cell (MCFC), were examined in the mixture of 62 mol% Li<SUB>2</SUB>CO<SUB>3</SUB>-38 mol% K<SUB>2</SUB>CO<SUB>3</SUB> at 650 <SUP>o</SUP>C by measuring the change in corrosion potential and potentiodynamic response of the alloys and also in terms of impedance analysis on the alloy|oxide layer|electrolyte system. The corrosion potential of SS 316L was in an active region for 12 h-immersion, whereas that of SS 310S drastically increased after 6 h-immersion due to an active to passive transition. The corrosion rate of the two SSs decreased with immersion due to the growth of protective oxide. However, the decrease in the corrosion rate of SS 310S is much greater than that of SS 316L. The oxide formed on the two SSs was found to be duplex layer, composed of inner Cr enriched oxide and outer Fe enriched oxide. However, the inner Cr enriched layer of 310S is more clearly separated from the outer Fe enriched layer than that of SS 316L due primarily to the higher Cr content in SS 310S. The drastic increase in the corrosion potential of SS 310S after 6 h-immersion is closely associated with the growth of the inner Cr enriched oxide layer. The corrosion resistance of SS depends dominantly on the resistance of the inner Cr enriched oxide that is determined form the impedance analysis on the alloy|oxide layer|electrolyte system. The higher corrosion resistance of SS 310S compared with SS 316L results from the more protective inner Cr enriched oxide layer, as confirmed by its higher resistance associated with the higher Cr content in SS 310S.