Yuko Ogo, Takanori Kobayashi, Reiko Nakanishi Itai, Hiromi Nakanishi, Yusuke Kakei, Michiko Takahashi, Seiichi Toki, Satoshi Mori, Naoko K. Nishizawa.
J. Biol. Chem. 283, 13407-13417 (2008) | doi:10.1074/jbc.M708732200
Iron is essential for most living organisms, and thus iron deficiency poses a major abiotic stress in crop production. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified a novel transcription factor of rice and barley, IDEF2, which specifically binds to the iron deficiency-responsive cis-acting element 2 (IDE2) by yeast one-hybrid screening. IDEF2 belongs to an uncharacterized branch of the NAC transcription factor family and exhibits novel properties of sequence recognition. An electrophoretic mobility shift assay and cyclic amplification and selection of targets experiment revealed that IDEF2 predominantly recognized CA(A/C)G(T/C)(T/C/A)(T/C/A) within IDE2 as the core-binding site. IDEF2 transcripts are constitutively present in rice roots and leaves. Repression of the function of IDEF2 by the RNA interference (RNAi) technique and chimeric repressor gene-silencing technology (CRES-T) caused aberrant iron homeostasis in rice. Several genes up-regulated by iron deficiency, including the Fe(II)-nicotianamine transporter gene OsYSL2, were less induced by iron deficiency in the RNAi rice of IDEF2, suggesting that IDEF2 is involved in the regulation of these genes. Many genes with repressed expression in IDEF2 RNAi rice possessed the IDEF2-binding core sites in their promoters, and the flanking sequences were also highly homologous to IDE2. IDEF2 bound to OsYSL2 promoter region containing the binding core site, suggesting direct regulation of OsYSL2 expression. These results reveal novel cis-element/trans-factor interactions functionally associated with iron homeostasis.# 転写因子の活性を高めたら、鉄の過剰摂取による障害は起きないんだろうか？
# 実際のところ、腹びれなのか何なのか…
# ミクロの世界は…あ、違った、ナノの世界もまた美しい
# まぁ、しょうがないわね…ブッシュなんかをいつまでも大統領に据えておいたんだから…
# ようやくHD画像で公開です
# ある変動の一面だけを切り取ってそれを外挿してみても、説得力があるとは言い難い…
# 手足口病を侮る無かれ
Philip L. Llewellyn, Sandrine Bourrelly, Christian Serre, Alexandre Vimont, Marco Daturi, Lomig Hamon, Guy De Weireld, Jong-San Chang, Do-Young Hong, Young Kyu Hwang, Sung Hwa Jhung, Gérard Férey.
Langmuir, ASAP Article | doi:10.1021/la800227x
Mesoporous MOFs MIL-100 and MIL-101 adsorb huge amounts of CO2 and CH4. Characterization was performed using both manometry and gravimetry in different laboratories for isotherms coupled with microcalorimetry and FTIR to specify the gas-solid interactions. In particular, the uptake of carbon dioxide in MIL-101 has been shown to occur with a record capacity of 40 mmol g-1 or 390 cm3STP cm-3 at 5 MPa and 303 K.
Bo Wang, Adrien P. Côté, Hiroyasu Furukawa, Michael O'Keeffe, Omar M. Yaghi.
Nature 453, 207-211 (2008) | doi:10.1038/nature06900
Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials with tetrahedral networks that resemble those of zeolites: transition metals (Zn, Co) replace tetrahedrally coordinated atoms (for example, Si), and imidazolate links replace oxygen bridges. A striking feature of these materials is that the structure adopted by a given ZIF is determined by link–link interactions, rather than by the structure directing agents used in zeolite synthesis. As a result, systematic variations of linker substituents have yielded many different ZIFs that exhibit known or predicted zeolite topologies. The materials are chemically and thermally stable, yet have the long-sought-after design flexibility offered by functionalized organic links and a high density of transition metal ions. Here we report the synthesis and characterization of two porous ZIFs―ZIF-95 and ZIF-100―with structures of a scale and complexity previously unknown in zeolites. The materials have complex cages that contain up to 264 vertices, and are constructed from as many as 7,524 atoms. As expected from the adsorption selectivity recently documented for other members of this materials family, both ZIFs selectively capture carbon dioxide from several different gas mixtures at room temperature, with ZIF-100 capable of storing 28 litres per litre of material at standard temperature and pressure. These characteristics, combined with their high thermal and chemical stability and ease of fabrication, make ZIFs promising candidate materials for strategies aimed at ameliorating increasing atmospheric carbon dioxide levels.# CO2吸収剤で吸収したとして、それをどう処理するのか…そして、そのCO2をどう炭素循環に復帰させるのか…
N. S. Keenlyside, M. Latif, J. Jungclaus, L. Kornblueh, E. Roeckner.
Nature 453, 84-88 (2008) | doi:10.1038/nature06921
The climate of the North Atlantic region exhibits fluctuations on decadal timescales that have large societal consequences. Prominent examples include hurricane activity in the Atlantic, and surface-temperature and rainfall variations over North America, Europe and northern Africa. Although these multidecadal variations are potentially predictable if the current state of the ocean is known, the lack of subsurface ocean observations that constrain this state has been a limiting factor for realizing the full skill potential of such predictions. Here we apply a simple approach―that uses only sea surface temperature (SST) observations―to partly overcome this difficulty and perform retrospective decadal predictions with a climate model. Skill is improved significantly relative to predictions made with incomplete knowledge of the ocean state, particularly in the North Atlantic and tropical Pacific oceans. Thus these results point towards the possibility of routine decadal climate predictions. Using this method, and by considering both internal natural climate variations and projected future anthropogenic forcing, we make the following forecast: over the next decade, the current Atlantic meridional overturning circulation will weaken to its long-term mean; moreover, North Atlantic SST and European and North American surface temperatures will cool slightly, whereas tropical Pacific SST will remain almost unchanged. Our results suggest that global surface temperature may not increase over the next decade, as natural climate variations in the North Atlantic and tropical Pacific temporarily offset the projected anthropogenic warming.# そういう短周期的な気温低下で、地球温暖化を否定したがる輩が急増するのがまた愚かしい…
