Interaction between the Helicobacter pylori CagA and -Pix in Gastric Epithelial AGS Cells

BAEK, H. Y.,WEON LIM, J.,KIM, H. Wiley (Blackwell Publishing) 2007 Annals of the New York Academy of Sciences Vol.1096 No.1

<P>The gastric pathogen Helicobacter pylori (H. pylori) translocates the CagA protein into epithelial cells by a type IV secretion process. Upon translocation into the host cell cytosol, CagA undergoes tyrosine phosphorylation. Phosphorylation of CagA occurs within the C terminus of the protein and is mediated by members of the Src family of tyrosine kinases. Phosphorylation of CagA induces the dephosphorylation of as yet unidentified cellular proteins, rearrangements of the host cell actin cytoskeleton, and cell scattering. This article aims to determine the cellular protein that interacts with CagA. Gastric epithelial AGS cells were stimulated with CagA-positive H. pylori (NCTC11637, at a bacteria/cell ratio of 500:1) and cultured in antibiotic-free medium. Proteins were isolated from the cells with or without H. pylori infection. CagA-interactive protein was determined by immunoprecipitation using anti-CagA antibody and proteomic analysis. We found that alpha-Pix interacts with CagA and alpha-Pix was constitutively expressed in AGS cells. Upon H. pylori stimulation, CagA was translocated into the cells and the expression of alpha-Pix (PAK-interactive exchange factor) was increased in AGS cells time dependently. The interaction of alpha-Pix with CagA was increased by H. pylori infection in AGS cells. Phosphorylation of CagA induces the dephosphorylation of alpha-Pix in AGS cells. alpha-Pix is a family of PAK-binding proteins that strongly activates PAK (p21-activated tyrosine kinase). PAK regulates changes in gene expression and mediates actin cytoskeletal and cell morphological changes. The novel finding of this study is that phosphorylation of CagA induces the dephosphorylation of alpha-Pix, which may modulate cytoskeletal changes of gastric epithelial cells through PAK.</P>

Self-standing and shape-memorable UV-curing epoxy polymers for three-dimensional (3D) continuous-filament printing

Sun, H.,Kim, Y.,Kim, Y. C.,Park, I. K.,Suhr, J.,Byun, D.,Choi, H. R.,Kuk, K.,Baek, O. H.,Jung, Y. K.,Choi, H. J.,Kim, K. J.,Nam, J. D. The Royal Society of Chemistry 2018 Journal of materials chemistry. C, Materials for o Vol.6 No.12

<P>In the development of three-dimensional printable materials for high-speed and high-resolution printing, UV-curing polymers can guarantee fast and precise printing of high performance load-bearing structures, but the injected drops of the monomers tend to spread over the substrates due to their low viscosity. In this study, we imposed the self-standing and shape-memorable capability of an epoxy acrylate (EA) monomer to ensure continuous filamentary 3D printing while maintaining its low viscosity nature. Using octadecanamide (ODA) with EA, strong hydrogen-bond networks (−N−H⋯OC−, −N−CO⋯H-O-, -N-H⋯N-) were additionally achieved in the material system and the developed material distinctively exhibited rheological duality at different processing stages: a low-viscosity liquid-like behavior (viscosity of ∼50 Pa) while passing through the nozzle and a self-standing solid-like behavior (static yield stress of ∼364 Pa) right after being printed. This reversible liquid-to-solid transitional capability was quantified by viscoelastic complex moduli provided a dynamic yield stress (<I>τ</I>y,G) of 210 Pa corresponding to the upright stacking up to ∼3.2 cm (3 wt% of ODA). The time (<I>t</I>y,G) required for conformational rearrangement was evaluated to be as fast as ∼10<SUP>−2</SUP> s. After UV curing, the 3D printed layers exhibited no air pockets or weld lines at the stacked interfaces, which could guarantee excellent mechanical performance and structural integrity.</P>

Dependence of the exchange bias and coercivity of [Pd/Ferromagnet]_N/FeMn multilayers on the stack number N

Joo, H.W.,Lee, M.S.,Kim, S.W.,Kim, S.S.,Lee, J.Y.,Baek, J.Y.,You, C.-Y.,Lee, K.A.,Rhee, J.R.,Lee, S.S.,Hwang, D.G. IEEE 2006 IEEE transactions on magnetics Vol.42 No.10

The dependencies of the stack number N on perpendicular exchange-biasing (H<SUB>ex</SUB>) and coercivity H<SUB>c</SUB>) in [Pd/Co]<SUB>N</SUB> and [Pd/Co (or CoFe)]<SUB>N</SUB>/FeMn multilayers were investigated. With the help of the careful designs of layer structures, a series of samples whose surface anisotropies have the linear function N was prepared with constant bulk anisotropies. From the experimental data obtained, it was found that H<SUB>ex</SUB> does not depend on the surface anisotropy, while H<SUB>c</SUB> shows a strong dependence. Therefore, it is possible to tailor wide ranges of H<SUB>c</SUB> (300-600 Oe) without varying H<SUB>ex</SUB>(∼200 Oe) through the single control parameter stack number N.

In vivo imaging of tumor apoptosis using histone H1-targeting peptide

Wang, K.,Purushotham, S.,Lee, J.Y.,Na, M.H.,Park, H.,Oh, S.J.,Park, R.W.,Park, J.Y.,Lee, E.,Cho, B.C.,Song, M.N.,Baek, M.C.,Kwak, W.,Yoo, J.,Hoffman, A.S.,Oh, Y.K.,Kim, I.S.,Lee, B.H. Elsevier Science Publishers 2010 Journal of controlled release Vol.148 No.3

In vivo imaging of apoptosis could allow monitoring of tumor response to cancer treatments such as chemotherapy. Using phage display, we identified the CQRPPR peptide, named ApoPep-1(Apoptosis-targeting Peptide-1), that was able to home to apoptotic and necrotic cells in tumor tissue. ApoPep-1 also bound to apoptotic and necrotic cells in culture, while only little binding to live cells was observed. Its binding to apoptotic cells was not dependent on calcium ion and not competed by annexin V. The receptor for ApoPep-1 was identified to be histone H1 that was exposed on the surface of apoptotic cells. In necrotic cells, ApoPep-1 entered the cells and bound to histone H1 in the nucleus. The imaging signals produced during monitoring of tumor apoptosis in response to chemotherapy was enhanced by the homing of a fluorescent dye- or radioisotope-labeled ApoPep-1 to tumor treated with anti-cancer drugs, whereas its uptake of the liver and lung was minimal. These results suggest that ApoPep-1 holds great promise as a probe for in vivo imaging of apoptosis, while histone H1 is a unique molecular signature for this purpose.

PdO-doped BaZr_0.8Y_0.2O_3-δ electrolyte for intermediate-temperature protonic ceramic fuel cells

Baek, S.S.,Park, K.Y.,Lee, T.H.,Lee, N.,Seo, Y.,Song, S.J.,Park, J.Y. Elsevier Science 2014 Acta materialia Vol.66 No.-

This paper explores the potential to design a ''superprotonic conductor'' for operation in the intermediate temperature (IT) range through a doping approach with a conventional proton conductor. This approach is validated scientifically, based on the enhanced macroscopic transport properties of the oxide ion conductor. This system consists of a BaZr<SUB>0.8</SUB>Y<SUB>0.2</SUB>O<SUB>3-δ</SUB> (BZY) proton conductor and a small amount of palladium oxide (PdO). The influence of the PdO on the sinter activity of the highly refractory BZY material is not significant, with low rates of grain growth under typical sintering conditions, even though the addition of some PdO favors the grain growth of BZY materials to some extent. The conductivity of PdO-modified BZY (BZPY) is higher than that of BZY in the IT range, in all atmospheres and at all temperatures. The conductivity of 3mol.% PdO-modified BZPY was 8.60x10<SUP>-3</SUP>Scm<SUP>-1</SUP> at 600<SUP>o</SUP>C in wet 5% H<SUB>2</SUB>. The electrical conductivity of BZPY increases systematically with increasing PdO content (0.5-3mol.%) in all atmospheres investigated.

Efficient xeno-free culture system for human embryonic stem cells

Baek J.A.,Seol H.W.,Jung J.,Yoon B.A.,Kim H.S.,Oh S.K.,Koo S.,Kim S.H.,Moon S.Y.,Choi Y.M. 한국발생생물학회 2011 한국발생생물학회 학술발표대회 Vol.30 No.-

The development of humanized culture system of human embryonic stem cells (hESCs) hold promise for therapeutic applications. However, conventional culture system contain animal-derived components such as fetal bovine serum and mouse embryonic fibroblasts that bear a risk of transmitting non-human pathogens and incorporation of non-human immunogenic molecules to hESCs. In this study, we developed an efficient xeno-free hESCs culture system using humanized materials, the CELLstartTM, human foreskin feeder and xeno-free medium containing knockOutTM SR XenoFree (XF-medium) without animal-derived material. The hESCs were gradually adapted to the XF-medium; 25:75, 50:50, 75:25 and 100:0. Two karyotypically normal hESC lines, SNUhES4 and H1, were used for the experiments of xeno-free culture condition. The attachment rates at xeno-free culture system were 52.6±12.4%, 67.0±16.6%, 59.0±13.9%, 28.3±2.9% in SNUhES4, 79.3±5.4%, 53.8±20.9%, 69.4 ±6.4%, 59.8±12.6% in H1 and the spontaneous differentiation rates were 42.2±12.7%, 31.4±2.9%, 40.8±14.5%, 55.2±35.5% in SNUhES4, 35.6±8.5%, 36.4±13.5%, 48.4±7.8%, 80.1±6.0% in H1 in the first four passage. Although the attachment rates were low and the spontaneous differentiation rates were high compared to that of conventional system in the early passages using this humanized culture condition, hESCs in this culture condition were found to maintain hESC characterizations; morphology, expression of cell surface markers and stable karyotype. Our results indicate that simplified compositions of humanized culture system can be applicable to the further optimization for a xeno-free culture of hESCs without the loss of pluripotency and contamination from xenogenic sources.

H.264/AVC 에서 잔여 신호의 상관도에 기반한 화면 간 16x16 예측 모드의 선택적 다차원 변환 방법

백승용(S. Y. Baek),조혜정(H. J. Cho),오승준(S. J. Oh) 한국통신학회 2011 한국통신학회 학술대회논문집 Vol.2011 No.2

Estrus synchronization affects galectin-3, FGF-9 signaling in the sow reproductive tract

Baek S. Y,Kim D. W,Min Y. J,Cho E. S,Choi T. J,Soh H. C,Kim Y. M,Kang S. J,Kim B. K,Cho K. H,Cho K. H1 한국수정란이식학회 2017 한국수정란이식학회 학술대회 Vol.2017 No.05

The purpose of this study was to investigate the effect of estrus synchronization to altrenogest regumate (progesterone), PMSG/hCG, and artificial insemination (AI) on galectin-3, FGF-9 gene and protein expression. The morpho-metrical parameters of the endometrium and the number of corpora lutea (CL) were recorded. RNA was isolated from endometrial, oviduct and ovary tissues of non-synchronized (Control; n = 7) and AI synchronized (regumate, PMSG/hCG; n = 7) sows. The total number of CL was higher (P<0.05) in pigs treated with regumate/PMSG/hCG. The content of gelactin-3 and FGF-9 mRNA in pre-embryonic development stages increased on particular days, in control and studied in regumate/PMSG/hCG administered pigs. Gelactin-3 and FGF-9 were affected by regumate/PMSG/hCG treatment in the both pre-embryonic development stages (P<0.001, P<0.05) and encdometrial tissue (P<0.001, P<0.01). The regumate/PMSG/hCG treatment resulted in elevated expression of gelactin-3 (P<0.001) and FGF-9 (P<0.005) in oviduct and ovary tissues in comparison to control sows. Moreover, oviduct amount of gelectin-3 mRNA was higher in regumate/PMSG/hCG sows in comparison to the control group (P<0.05), whereas, expression characteristics of gelactin-3 and FGF-9 were investigated by hematoxylin and eosin stained and immunohistochemical staining. The results showed that galectin-3 and FGF-9 were significantly shown in the endometrium, oviduct and ovary tissues of the regumate/PMSG/ hCG. Presented data show that exogenous hormones administration can affect gene and protein expression in the sow reproductive tract.

Production of Interferon Tau and TGF-β by Porcine Embryos

S. Y. Baek,H. C. Soh,E. S. Cho,T. J. Choi,Y. M. Kim,S. J. Kang,K. H. Cho,H. J. Chung 한국동물생명공학회(구 한국동물번식학회) 2017 Reproductive & Developmental Biology(Supplement) Vol.41 No.2

In pigs, expression and amounts of biologically active interferon tau (IFNT) and transforming growth factor-β (TGF-β) at the conceptus-maternal interface increase significantly as conceptuses elongate and begin the implantation process. Epidermal growth factor (EGF) acts through EGF receptor (EGFR) present in the blastocyst seems to regulate embryonic production of IFNT. To understand the mechanisms regulating the interaction between the hatched blastocyst and maternal uterine environment, the production of IFNT and TGF-β were investigated. Hatched pig blastocysts (days 7~10) were cultured and exposed to EGF (0, 1, 10 and 100 ng/mL) for 24, 48 and 72 h. Protein concentrations of IFNT in the cultured media were determined by commercial enzyme-linked immunosorbent assay (ELISA) kit. Epidermal growth factor (10 and 100 ng/mL) increased embryonic production of IFNT and TGF-β production by hatched blastocysts. The above results suggest that epidermal growth factor produced by epithelial cell stimulates the production of IFNT by pig trophoblasts. The capacity of conceptus to increase IFNT and TGF-β production in response to EGF stimulation may be important for the establishment of pregnancy in pig.

한우에 있어서 Rosette Inhibition Test 에 의한 조기 임신인자(Early Pregnancy Factor)의 검출

성환후,백광수,고응규,신기준,박용윤,신원집 한국축산학회 1997 한국축산학회지 Vol.39 No.4

Early pregnancy factor(EPF) is one of the pregnancy associated proteins, and it is detected in senun of many pregnant animals shortly after fertilization. The present study was conducted to establish a system of early pregnancy by EPF detection in Hanwoo cows. The EPF activity was measured by the rosette inhibition test on day 15 after artificial insemination or non-insemination. The rate of rosette formation between Hanwoo lymphocytes and sheep red blood cells was significantly(P$lt;0.05) higher compared to that between Hanwoo lymphocytes and goat, or rabbit red blood cells. The rosette formation between lymphocytes suspension and sheep red blood cells with anti-lymphocytes was not significantly(P$lt;0.05) changed until 5∼20 min. of culture, and then decreased dramatically by 30 min. There were significant(P$lt;0.05) differences in the rosette inhibition titer(RIT) between pregnant and non-pregnant Hanwoos on day 15 after artificial insemination. The results indicate that the expression of early pregnancy factor by the rosette inhibition test might be used to diagnosis of early pregnancy in Hanwoo.