Comparison of contractile mechanisms of sphingosylphosphorylcholine and sphingosine-1-phosphate in rabbit coronary artery

Choi, S.-K.,Ahn, D.-S.,Lee, Y.-H. Oxford University Press 2009 Cardiovascular research Vol.82 No.2

<P>AIMS: Although stimulation with sphingosylphosphorylcholine (SPC) or sphingosine-1-phosphate (S1P) generally leads to similar vascular responses, the contractile patterns and their underlying signalling mechanisms are often distinct. We investigated the different reliance upon Ca2+-dependent and Ca2+-sensitizing mechanisms of constriction in response to SPC or S1P in coronary arteries. METHODS AND RESULTS: Contractile responses, changes in [Ca2+]i, and phosphorylation of myosin light chain phosphatase-targeting subunit (MYPT1) were measured. SPC induced a concentration-dependent sustained contraction. S1P evoked a rapid rise in force (initial transient), which was followed by a secondary sustained force. In the absence of extracellular Ca2+, the concentration dependency of constriction to SPC was shifted to the right, but with no change in maximum force, whereas S1P-induced contraction was significantly blunted. Cyclopiazonic acid (CPA) significantly decreased the initial transient force induced by S1P. In isolated single cells, S1P markedly increased [Ca2+]i, whereas only a modest elevation was noted with SPC. The S1P-induced elevation of [Ca2+]i was abolished by pre-treatment with CPA and was significantly reduced in the absence of extracellular Ca2+. In beta-escin-permeabilized strips, SPC augmented pCa 6.3-induced force; this was significantly inhibited by fasudil hydrochloride. S1P induced little or no augmentation of pCa 6.3-induced force. In intact arteries, SPC-induced contraction was completely inhibited by fasudil hydrochloride. Fasudil hydrochloride had no effect on the initial transient force induced by S1P but significantly inhibited the secondary sustained force. SPC induced a several-fold increase in Thr696 and Thr853 phosphorylation of MYPT1, but S1P did not affect phosphorylation of MYPT1. CONCLUSION: Our results suggest that constriction of coronary arteries in response to the bioactive lipid S1P or SPC occurs by distinct signalling pathways. Activation of the RhoA/RhoA-associated kinase pathway and subsequent phosphorylation of MYPT1 play a key role in SPC-induced coronary contraction, whereas elevation of [Ca2+]i is crucial for S1P-induced coronary constriction.</P>

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.

[ $^1H$ ] 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.

ZNF509S1 downregulates PUMA by inhibiting p53K382 acetylation and p53-DNA binding

Jeon, B.N.,Yoon, J.H.,Han, D.,Kim, M.K.,Kim, Y.,Choi, S.H.,Song, J.,Kim, K.S.,Kim, K.,Hur, M.W. Elsevier Science 2017 Biochimica et biophysica acta. Gene regulatory mec Vol.1860 No.9

Expression of the POK family protein ZNF509L, and -its S1 isoform, is induced by p53 upon exposure to genotoxic stress. Due to alternative splicing of the ZNF509 primary transcript, ZNF509S1 lacks the 6 zinc-fingers and C-terminus of ZNF509L, resulting in only one zinc-finger. ZNF509L and -S1 inhibit cell proliferation by activating p21/CDKN1A and RB transcription, respectively. When cells are exposed to severe DNA damage, p53 activates PUMA (p53-upregulated modulator of apoptosis) transcription. Interestingly, apoptosis due to transcriptional activation of PUMA by p53 is attenuated by ZNF509S1. Thus we investigated the molecular mechanism(s) underlying the transcriptional attenuation and anti-apoptotic effects of ZNF509S1. We show that ZNF509S1 modulation of p53 activity is important in PUMA gene transcription by modulating post-translational modification of p53 by p300. ZNF509S1 directly interacts with p53 and inhibits p300-mediated acetylation of p53 lysine K382, with deacetylation of p53 K382 leading to decreased DNA binding at the p53 response element 1 of the PUMA promoter. ZNF509S1 may play a role not only in cell cycle arrest, by activating RB expression, but also in rescuing cells from apoptotic death by repressing PUMA expression in cells exposed to severe DNA damage.

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.

Diagnostic usefulness of a T cell-based assay for latent tuberculosis infection in kidney transplant candidates before transplantation

Kim, S.-H.,Lee, S.-O.,Park, I.-A.,Park, S.J.,Choi, S.-H.,Kim, Y.S.,Woo, J.H.,Park, S.-K.,Park, J.S.,Kim, S.C.,Han, D.J. Blackwell Publishing Inc 2010 Transplant infectious disease Vol.12 No.2

<P>S.-H. Kim, S.-O. Lee, I.-A. Park, S.J. Park, S.-H. Choi, Y.S. Kim, J.H. Woo, S.-K. Park, J.S. Park, S.C. Kim, D.J. Han. Diagnostic usefulness of a T cell-based assay for latent tuberculosis infection in kidney transplant candidates before transplantation.Transpl Infect Dis 2010: <B>12:</B> 113–119. All rights reserved</P><P>Background</P><P>The presence of latent tuberculosis (TB) infection (LTBI) should be evaluated before kidney transplantation. Although a new T cell-based assay for diagnosing LTBI gave promising results, this assay has not yet been compared with the tuberculin skin test (TST) for diagnosing LTBI in renal transplant candidates before transplantation.</P><P>Patients and methods</P><P>All adult patients admitted to a single institute for renal transplantation over a 1-year period were prospectively enrolled. A clinically predictive risk of LTBI was defined as: (i) recent close contact with a person with pulmonary TB; (ii) abnormal chest radiography; (iii) a history of untreated or inadequately treated TB; or (iv) a new infection (i.e., a recent conversion of TST).</P><P>Results</P><P>Of 209 renal recipients, 47 (22%) had a positive TST≥5 mm, 21 (10%) had a positive TST≥10 mm, 65 (30%) had a positive T-SPOT.<I>TB</I> test, and 25 (12%) had an indeterminate T-SPOT.<I>TB</I> test. The induration size of TST was significantly associated with a high positivity rate on T-SPOT.<I>TB</I> (<I>P</I><0.001). Agreement between T-SPOT.<I>TB</I> test and TST≥10 mm was fair (<I>k</I>=0.24, 95% confidence interval 0.11–0.36). However, neither univariate nor multivariate analysis showed any association between the clinical risk for LTBI and positivity on T-SPOT.<I>TB</I> or TST.</P><P>Conclusion</P><P>T-SPOT.<I>TB</I> test was more frequently positive than TST in renal transplant candidates. However, further longitudinal studies are awaited to determine whether the ability of T-SPOT.<I>TB</I> assay to detect LTBI in renal transplant recipients can better predict the development of TB than can TST after transplantation.</P>

Fatigue performance of deepwater SCR under short-term VIV considering various S-N curves

Kim, D.K.,Choi, H.S.,Shin, C.S.,Liew, M.S.,Yu, S.Y.,Park, K.S. Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.5

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatigue life of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs were considered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.

벼 육묘트레이를 이용한 어린 잎 채소 생육에 미치는 광 조절 영향

최기영 ( K. Y. Choi ),김시홍 ( S. H. Kim ),김재경 ( J. K. Kim ),유형주 ( H. J. Yoo ),김일섭 ( I. S. Kim ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2016 강원 농업생명환경연구 Vol.28 No.2

벼 육묘 트레이를 활용한 어린잎 채소 재배 가능성을 탐색하고자 재배 기간 중 차광 처리하여 다채, 청경채, 알파인배추, 청치마 상추 등 4종을 17일간 재배하였다. 차광 처리는 무차광 17일(NS), 차광 8일+무차광 9일 (S8NS9), 무차광 8일+차광 9일(NS8S9), 차광 17일(S17) 하였다. 처리에 따른 누적 광량은 NS>S8NS9>NS8S9>S17처리구 순으로 높았으나, 누적 온도는 처리에 따른 차이가 크지 않았다 차광 8일 째 어린잎채소 4종의 생육과 엽록소함량은 감소하였다. 광 조절 17일 째 어린잎채소 4종의 초장, 엽장, 엽폭, 경경, 생체중, 엽록소 함량 등의 생육은 무차광 NS 처리구에서 가장 높았다. 생육 초기 광조절에 따른 생육 후기 초장과 생체중 증가율이 어린잎채소 4종 모두 NS 또는 S8NS9 처리구에서 높았다. 따라서 벼 육묘장 다층 시스템에서의 공간 활용을 고려한 어린잎채소 재배시 차광이 많은 하부 공간은 생육초기에 활용하고, 수확기에는 광 확보가 이루어지는 상부에서 재배가 이루어짐이 적합하리라 본다. This study was conducted to investigate the effect of light control on growth of baby leaf vegetables (tatsoi, pak-choi, chinese cabbage ‘alpine’ and leaf lettuce ‘cheongchima’) in rice seedling tray. Light treatment controlled in non-shading (NS), shading for 8 days+non-shading for 9 days (S8NS9), non-shading for 8 days+shading for 9 days (NS8S9), and shading for 17 days (S17). Integrated solar radiation in NS was highest, and in S8NS9>NS8S9>S17 order. Integrated temperature did not shown difference among the treatments for growing periods. Growth and chlorophyll content of baby leaf vegetables were lowest in shading treatment for 8days. The highest growth characteristics (plant height, leaf length, leaf width, stem diameters, and fresh weight) and chlorophyll content of baby leaf vegetables was shown in NS. Increment rate of plant height and fresh weight of baby leaf vegetables were high in NS or S8NS9 as affected by light control for 8 days in early growth periods. These results suggest that we can utilize in low layer for early period and in high layer for harvest periods for baby vegetable production in rice seedling factory.

放射菌을 利用한 異種間 原形質體 融合과 그 融合體의 安定性에 관한 硏究(Ⅱ)

閔洪基,金昌珉,孫麗源,韓惠勝,崔英珠,丁大映,韓康玄,李相燮,李欽淑,元奉必 국립보건연구원 1992 국립보건원보 Vol.29 No.2

반추위 곰팡이의 분리 · 동정과 섬유소 분해효소의 특성구명 및 이들의 산업적 이용에 관한 연구 (4) 한우 및 재래산양의 반추위에서 분리된 곰팡이의 섬유소 분해력 측정

이성실(S . S . Lee),하종규(J . K . Ha),최윤재(Y . J . Choi),한인규(In K . Han),김창현(C . H . Kim),강수현(S . H . Kang) 한국영양사료학회 1995 韓國營養飼料學會誌 Vol.19 No.5