Disturbed flow: p53 SUMOylation in the turnover of endothelial cells

Takabe, Wakako,Alberts-Grill, Noah,Jo, Hanjoong The Rockefeller University Press 2011 The Journal of cell biology Vol.193 No.5

<P>Disturbed blood flow induces apoptosis of vascular endothelial cells, which causes atherosclerosis. In this issue, Heo et al. (2011. <I>J. Cell Biol</I>. doi:10.1083/jcb.201010051) sheds light on p53’s role in this phenomenon. Disturbed flow induces peroxynitrite production, which activates protein kinase C ζ and it’s binding to the E3 SUMO (small ubiquitin-like modifier) ligase PIASy (protein inhibitor of activated STATy). This leads to p53 SUMOylation and its export to the cytosol, where it binds to the antiapoptotic protein Bcl-2 to induce apoptosis.</P>

Multimedia Mobile Access Communication ( MMAC ) Study Committee Summary Report

Yoshiyuki Takabe,Etsuko Nakanishi,Yuji Nakamura 대한전자공학회 1996 대한전자공학회 워크샵 Vol.1996 No.-

On the Existence of Oscillatory Behavior in Gene Regulatory Networks with Cyclic Interconnections

Yutaka Hori,Akifumi Takabe,Shinji Hara 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper, we derive an existence condition of periodic oscillationsin cyclic gene regulatory networks, of which the dynamical behavior is described by nonlinear differential equations. For this purpose, we first point out that change of the equilibrium point with respect to biochemical parameters is important for comprehensive analysis, and show the properties which the equilibrium point should satisfy. Then, by employing the seproperties, we derive an analytic condition for the existence of periodic oscillationsincy clicgene regulatory networks where genes have homogeneous dynamics Compared to preceding studies, our condition has the following distinctive features: (i) it is analytically written only interms of the system parameters,(ii) it is applicable for cyclicgene regulatory networks consisting of any number of genes. Thus, biological inter pretation of the result is easily obtained, and, infact, it is concluded that cyclic generegulatory networks with homogeneous genedynamics tend to have periodicos cillations as the number of genes gets large. Finally, we discuss the case of cyclicgene regulatory networks with heterogeneous genedynamics.

Numerical Study of AGN Jet Propagation with Two Dimensional Relativistic Hydrodynamic Code

MIZUTA AKIRA,YAMADA SHOICHI,TAKABE HIDEAKI The Korean Astronomical Society 2001 Journal of The Korean Astronomical Society Vol.34 No.4

We investigate the morphology of Active Galactic Nuclei(AGN) jets. AGN jets propagate over kpc $\~$ Mpc and their beam velocities are close to the speed of light. The reason why many jets propagate over so long a distance and sustain a very collimated structure is not well understood. It is argued that some dimensionless parameters, the density and the pressure ratio of the jet beam and the ambient gas, the Mach number of the beam, and relative speed of the beam compared to the speed of light, are very useful to understand the morphology of jets namely, bow shocks, cocoons, nodes etc. The role of each parameters has been studied by numerical simulations. But more research is necessary to understand it systematically. We have developed 2D relativistic hydrodynamic code to analyze relativistic jets. We pay attention to the propagation velocity which is derived from 1D momentum balance in the frame of the working surface. We show some of our models and discuss the dependence of the morphology of jets on the parameter.

Improved Mäule color reaction provides more detailed information on syringyl lignin distribution in hardwood

Yamashita, Daichi,Kimura, Satoshi,Wada, Masahisa,Takabe, Keiji Springer-Verlag 2016 Journal of wood science Vol.62 No.2

<P>The traditional Maule color reaction was improved by use of tris(hydroxymethyl) aminomethane-hydrochloride acid (Tris-HCl) buffer coupled with a fluorescence microscope. The purple-red color of Maule-treated hardwood was more stable with the novel treatment than with traditional treatment. In addition, Maule-treated wood samples had a characteristic fluorescence when excited with blue (460-495 nm) light. Examination of white birch (Betula platyphylla) showed that syringyl-rich and guaiacyl-rich cell walls emitted red and yellow fluorescence, respectively. Measuring the fluorescence spectra of hardwood and softwood powders after treatment with the new Maule reagents showed that hardwood powder containing syringyl lignin emitted a red fluorescence, whereas softwood powder containing guaiacyl lignin emitted a green fluorescence when excited with blue light. In conclusion, this improved technique has many advantages compared with the traditional Maule color test.</P>

내염성 cyanobacteria로 부터 danK heat shock protein 유전자의 cloning 및 특성 해명

원성혜,윤병욱,김학윤,이병현,Teruhiro Takabe 한국생명과학회 2001 생명과학회지 Vol.11 No.5

내염성의 광합성 cyanobateria 인 Aphanothece halophytica로 부터 molecular chaperone으로 가능하는 HSP70 homolog인 dnaK2 유전자를 cloning 하였다. 이 danK2 유전자는 616개의 아미노산으로 구성되었으며 추정되는 분자량 68 kDa 의 단백질을 code하고 있었다. 아미노산 서열로부터 추정되는 DnaK2 단백질의 구조를 분석하여 본 결과, 다른 원핵생물의 DanK2 단백질들이 공통적으로 갖는 특성인 N-terminal ATPase domain과 C-terminal의 peptide-binding domain이 잘 보존되어 있었으며, 다른 HSP70/DanK 단백질들과의 높은은 상동성을 나타내었다. 한편 danK2 유전자는 생장온도인 28$^{\circ}C$에서 낮은 수준으로 구성적으로 발현하였으며 heat stress에 의해 그 발현량이 급격히 증가하였다. 또한 A. halophytica를 고농도의 염 스트레스로 처리한 결과, heat stress가 없음에도 불구하고 그 발현량이 급격히 증가하였다. 이러한 결과들은 DnaK 단백질의 고온 또는 염 스트레스에 따른 세포의 손상을 보호하기 위하여 중요한 기능을 담당하고 있기 때문에 추정된다. A gene, dnaK2, encoding a distinct member of the HSP70 family of molecular chaperones is isolated from the halotolerant cyanobactrium Aphanothece halophytica. The dnak2 gene encodes a molecular wight of 68 kDa polypeptide with predicted 616 amino acid residues. The DnaK2 protein has a structural characteristic of bacterial DnaK homologues and shows high similarity to other HSP70/Dank proteins. The danK2 transcripts are hardly detectable at 28$^{\circ}C$ and strongly induced upon heat stress. It is also found that dnaK2 transcript is increased by high-salinity stress even in the absence of heat stress. These results suggest that the DnaK2 protein plays an important role in protecting A. halophytica against damage caused by salt stress at well as heat stress.

Distribution of Hemicelluloses in Warts and the Warty Layer in Normal and Compression Wood Tracheids of Cryptomeria Japonica

Jong Sik Kim,Tatsuya Awano,Arata Yoshinaga,Keiji Takabe 한국목재공학회 2011 목재공학 Vol.39 No.5

The distribution of arabino-4-O-methylglucuronoxylans (AGXs) and O-acetyl-galactoglucomamians (GGMs) in warts and the warty layer of tracheids in normal wood (NW) and compression wood (CW) of Cryptomeria japonica was investigated. Under field emission scanning electron microscope (FE-SEM) observation, warts and the warty layer of delignified NW and CW tracheids were degraded by xylanase treatment, indicating that warts and the warty layer contain high amounts of AGXs. However, the effect of xylanase was not observed in NW and CW tracheids before delignification, suggesting that AGXs in warts and the warty layer may be encrusted with lignin. After β-mannanase treatment, no noticeable changes were observed in warts and the warty layer of NW tracheids, indicating that warts and the warty layer contain either no or very few GGMs. Similar results to FE-SEM observations were also observed with immunogold labeling. AGX labeling was observed in warts and the warty layer of NW and CW tracheids, while GGM labeling was not detected. NW tracheids showed a much stronger density of AGX labeling than did CW tracheids in warts and the warty layer, indicating differences in the chemical compositions of warts and the warty layer between NW and CW tracheids.

Effect of ammonia treatment on white birch wood

Yamashita, Daichi,Kimura, Satoshi,Wada, Masahisa,Samejima, Masahiro,Takabe, Keiji Walter de Gruyter und Co 2018 Holzforschung Vol.72 No.1

<P><B>Abstract</B></P><P>Transverse sections of white birch (<I>Betula platyphylla</I>) were treated with anhydrous ammonia at 60-140°C (ammonia treatment, AT). As a result, the crystal structure of cellulose in the AT samples changed to cellulose III<SUB>I</SUB>, and acetamide was produced. The surface area of the AT samples, the amount of sugar released upon acid hydrolysis and the lignin content were not changed. However, a small amount of lignin became acid soluble. Mäule color reaction, indicative of the presence of syringyl lignin, showed decreasing color intensities with increasing temperature of AT. The results can be easily interpreted that AT affects ester linkages and side chains of hemicelluloses and syringyl lignin. In addition, AT was carried out on 1-μm thick transverse sections and block specimens. Xylanase treatment and immunolabeling revealed that AT enhances xylan degradation, but ray cells are resistant to xylanase even after AT. On the block sample, a deposited xylan layer appeared on the inner surface of fiber cell walls. Apparently, xylan moved to the surface in contact with the fluid ammonia during AT. The vessel cell wall did not show a similar migration effect, indicating a cell wall-specific interaction with ammonia.</P>