目次

Editorials

エネルギー効率を改善すれば、温暖化の進行を遅らせ、対策を進める時間が生み出せるかもしれない。

A way to buy time

doi: 10.1038/491637b

病気との闘いに、科学的に見て実現性のない過大な目標を掲げるのは、適切な戦略ではない。

Misguided cancer goal

doi: 10.1038/491637a

欧州の研究者は結束して、ホライズン2020計画の大幅な予算削減に反対の声を上げるべきだ。

A bleak Horizon

doi: 10.1038/491638a

News

ブルガリアの国立科学基金(BNSF)に、助成の決定をめぐって、激しい批判が。

Funding protest hits Bulgarian research agency

doi: 10.1038/491649a

厳しい予算削減が、欧州宇宙機関(ESA)の地球観測計画に大きな打撃を。

Space budget blow to climate science

doi: 10.1038/491645a

欧州が、日常的にされされる環境化学物質の健康への影響を調べるため、2つのプロジェクトを開始へ。

Daily dose of toxics to be tracked

doi: 10.1038/491647a

気象データの観測に、小型の商用衛星ネットワークを利用へ。

Microsatellites aim to fill weather-data gap

doi: 10.1038/491650a

ブラジルのバイオ燃料生産が、厳しい状況に。

Growth of ethanol fuel stalls in Brazil

doi: 10.1038/491646a

News Features

後戻りはできない

No going back

気候変動を遅らせる有効な手が打てないまま、多くの国で、避けられない温暖化に備える取り組みが加速している。

doi: 10.1038/491659a

京都議定書後の世界

After Kyoto

1997年に採択された京都議定書はまもなく終わりを迎えるが、この特集では、今後の道筋を探る。

doi: 10.1038/491653a

ホット・エア

Hot air

京都議定書では二酸化炭素排出削減を掲げたが、排出量はかつてない速さで増え続けている。

doi: 10.1038/491656a

炭素漬け

Awash in carbon

世界の国々では、化石燃料の利用がますます増えている。

doi: 10.1038/491654a

News & Views

計算物質科学:合金の性能を予測する

Computational materials science: Substitution with vision p.674

ある種の合金で、その材料がとりうる数百万もの原子配置について安定性や弾性を予測する方法が開発された。この手法は、最適化された特性を持つ材料を突き止めるのに役立ちそうだ。

doi: 10.1038/nature11755

植物生態学:危機に瀕する森林

Plant ecology: Forests on the brink p.675

多様な樹木の干ばつに対する生理的な脆弱性の評価から、地球上の森林はどれも、乾燥条件の激化に屈服する高い危険にさらされていることが明らかになった。

doi: 10.1038/nature11756

地球科学:ゆっくり暖められるマグマだまり

Earth science: Magma chambers on a slow burner p.677

海底にあるマグマだまりで起こっている結晶化過程の検討から、微量元素に予想外の濃縮が起こっていたことがわかった。このことはこうしたマグマだまり内でのマグマの循環という古い理論をよみがえらせることになる。

doi: 10.1038/491677a

ゲノミクス:「日々の糧」の原料のゲノムを解読

Genomics: Decoding our daily bread p.678

パンコムギのゲノムは大型で複雑であり、塩基配列の完全解読はまだ成功していない。だが、パンコムギ遺伝子の今までで最も包括的な解析が行われたことは、この重要な穀物の供給を最適化しようという努力を助けるものになるだろう。

doi: 10.1038/491678a

免疫学:ビタミンで免疫を誘導

Immunology: Vitamins prime immunity p.680

ビタミンB誘導体が、特殊化した免疫細胞を刺激する抗原提示タンパク質に結合するという知見は、免疫系が微生物感染を検出する新規な機序を示唆している。

doi: 10.1038/491680a

量子物理学:強く相関した輸送

Quantum physics: Strongly correlated transport p.681

電界効果トランジスタは、マイクロプロセッサー技術の基盤となっている。一種の電界効果トランジスタについて、インコヒーレント領域から強く相関した超流動領域への粒子輸送の調節が実証された。

doi: 10.1038/491681a

Perspectives

気候:近年の成層圏温度の変化傾向の謎

The mystery of recent stratospheric temperature trends p.692

doi: 10.1038/nature11579

Articles

地球:海洋底玄武岩中の微量元素分布に見られる全球パターン

The global pattern of trace-element distributions in ocean floor basalts p.698

The magmatic layers of the oceanic crust are created at constructive plate margins by partial melting of the mantle as it wells up. The chemistry of ocean floor basalts, the most accessible product of this magmatism, is studied for the insights it yields into the compositional heterogeneity of the mantle and its thermal structure. However, before eruption, parental magma compositions are modified at crustal pressures by a process that has usually been assumed to be fractional crystallization. Here we show that the global distributions of trace elements in ocean floor basalts describe a systematic pattern that cannot be explained by simple fractional crystallization alone, but is due to cycling of magma through the global ensemble of magma chambers. Variability in both major and incompatible trace-element contents about the average global pattern is due to fluctuations in the magma fluxes into and out of the chambers, and their depth, as well as to differences in the composition of the parental magmas.

doi: 10.1038/nature11678

遺伝:全ゲノムショットガン塩基配列解読法を用いたパンコムギゲノムの解析

Analysis of the bread wheat genome using whole-genome shotgun sequencing p.705

Bread wheat (Triticum aestivum) is a globally important crop, accounting for 20 per cent of the calories consumed by humans. Major efforts are underway worldwide to increase wheat production by extending genetic diversity and analysing key traits, and genomic resources can accelerate progress. But so far the very large size and polyploid complexity of the bread wheat genome have been substantial barriers to genome analysis. Here we report the sequencing of its large, 17-gigabase-pair, hexaploid genome using 454 pyrosequencing, and comparison of this with the sequences of diploid ancestral and progenitor genomes. We identified between 94,000 and 96,000 genes, and assigned two-thirds to the three component genomes (A, B and D) of hexaploid wheat. High-resolution synteny maps identified many small disruptions to conserved gene order. We show that the hexaploid genome is highly dynamic, with significant loss of gene family members on polyploidization and domestication, and an abundance of gene fragments. Several classes of genes involved in energy harvesting, metabolism and growth are among expanded gene families that could be associated with crop productivity. Our analyses, coupled with the identification of extensive genetic variation, provide a resource for accelerating gene discovery and improving this major crop.

doi: 10.1038/nature11650

遺伝:オオムギゲノムの物理的、遺伝学的および機能的な配列組み立て

A physical, genetic and functional sequence assembly of the barley genome p.711

Barley (Hordeum vulgare L.) is among the world’s earliest domesticated and most important crop plants. It is diploid with a large haploid genome of 5.1 gigabases (Gb). Here we present an integrated and ordered physical, genetic and functional sequence resource that describes the barley gene-space in a structured whole-genome context. We developed a physical map of 4.98 Gb, with more than 3.90 Gb anchored to a high-resolution genetic map. Projecting a deep whole-genome shotgun assembly, complementary DNA and deep RNA sequence data onto this framework supports 79,379 transcript clusters, including 26,159 ‘high-confidence’ genes with homology support from other plant genomes. Abundant alternative splicing, premature termination codons and novel transcriptionally active regions suggest that post-transcriptional processing forms an important regulatory layer. Survey sequences from diverse accessions reveal a landscape of extensive single-nucleotide variation. Our data provide a platform for both genome-assisted research and enabling contemporary crop improvement.

doi: 10.1038/nature11543

免疫:MR1はMAIT細胞に細菌のビタミンB代謝物を提示する

MR1 presents microbial vitamin B metabolites to MAIT cells p.717

Antigen-presenting molecules, encoded by the major histocompatibility complex (MHC) and CD1 family, bind peptide- and lipid-based antigens, respectively, for recognition by T cells. Mucosal-associated invariant T (MAIT) cells are an abundant population of innate-like T cells in humans that are activated by an antigen(s) bound to the MHC class I-like molecule MR1. Although the identity of MR1-restricted antigen(s) is unknown, it is present in numerous bacteria and yeast. Here we show that the structure and chemistry within the antigen-binding cleft of MR1 is distinct from the MHC and CD1 families. MR1 is ideally suited to bind ligands originating from vitamin metabolites. The structure of MR1 in complex with 6-formyl pterin, a folic acid (vitamin B9) metabolite, shows the pterin ring sequestered within MR1. Furthermore, we characterize related MR1-restricted vitamin derivatives, originating from the bacterial riboflavin (vitamin B2) biosynthetic pathway, which specifically and potently activate MAIT cells. Accordingly, we show that metabolites of vitamin B represent a class of antigen that are presented by MR1 for MAIT-cell immunosurveillance. As many vitamin biosynthetic pathways are unique to bacteria and yeast, our data suggest that MAIT cells use these metabolites to detect microbial infection.

doi: 10.1038/nature11605

生化学:寿命が短く出現頻度の低いRNA構造の可視化

Visualizing transient low-populated structures of RNA p.724

The visualization of RNA conformational changes has provided fundamental insights into how regulatory RNAs carry out their biological functions. The RNA structural transitions that have been characterized so far involve long-lived species that can be captured by structure characterization techniques. Here we report the nuclear magnetic resonance visualization of RNA transitions towards ‘invisible’ excited states (ESs), which exist in too little abundance (2–13%) and for too short a duration (45–250 μs) to allow structural characterization by conventional techniques. Transitions towards ESs result in localized rearrangements in base-pairing that alter building block elements of RNA architecture, including helix–junction–helix motifs and apical loops. The ES can inhibit function by sequestering residues involved in recognition and signalling or promote ATP-independent strand exchange. Thus, RNAs do not adopt a single conformation, but rather exist in rapid equilibrium with alternative ESs, which can be stabilized by cellular cues to affect functional outcomes.

doi: 10.1038/nature11498

Letters

宇宙:コンパクトなレンズ状銀河 NGC 1277における過度に大質量のブラックホール

An over-massive black hole in the compact lenticular galaxy NGC 1277 p.729

doi: 10.1038/nature11592

宇宙:タイタンの極循環反転から示された活動的な上層大気化学と力学

Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan p.732

doi: 10.1038/nature11611

物理:超流動フェルミ気体の流れにおける抵抗低下の観測

Observing the drop of resistance in the flow of a superfluid Fermi gas p.736

doi: 10.1038/nature11613

材料:100万通りの面心立法構造について確認された安定性と弾性の正準関係

A canonical stability–elasticity relationship verified for one million face-centred-cubic structures p.740

doi: 10.1038/nature11609

気候:過去15万年間にわたる氷床量と極域の気温の急速なカップリング

Rapid coupling between ice volume and polar temperature over the past 150,000 years p.744

doi: 10.1038/nature11593

進化:最古の有顎脊椎動物での歯および顎の発生

Development of teeth and jaws in the earliest jawed vertebrates p.748

doi: 10.1038/nature11555

生態:乾燥に対する森林の脆弱性に見られる大域的収束性

Global convergence in the vulnerability of forests to drought p.752

doi: 10.1038/nature11688

遺伝:Ficedula属ヒタキ類での種の分岐に関するゲノム全体像

The genomic landscape of species divergence in Ficedula flycatchers p.756

doi: 10.1038/nature11584

脳:霊長類内側嗅皮質にある視覚空間地図

A map of visual space in the primate entorhinal cortex p.761

doi: 10.1038/nature11587

再生医学:器官に適合した間充織による胚性幹細胞由来前駆細胞の自己複製

Self-renewal of embryonic-stem-cell-derived progenitors by organ-matched mesenchyme p.765

doi: 10.1038/nature11463

細胞:ヒトiPSC由来のTLR3欠損CNS細胞で見られるHSV-1に対する内因性免疫の障害

Impaired intrinsic immunity to HSV-1 in human iPSC-derived TLR3-deficient CNS cells p.769

doi: 10.1038/nature11583

免疫:抗体を欠損したマウスでの内在性レトロウイルスの再生

Resurrection of endogenous retroviruses in antibody-deficient mice p.774

doi: 10.1038/nature11599

生化学:リン脂質二重層中にあるケモカイン受容体CXCR1の構造

Structure of the chemokine receptor CXCR1 in phospholipid bilayers p.779

doi: 10.1038/nature11580

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