Not so neutral p.265
Switzerland’s science landscape is under threat after a narrow majority of citizens voted for tighter immigration rules that could restrict the number of foreign scientists who work in the country.
doi: 10.1038/506265a
Volume 506 Number 7488
今週のハイライト
Cover Story: 2種類はトラブルのもと：野生の花粉媒介昆虫を脅かすミツバチの新興感染病
幹細胞: 筋肉が老いるとき
幹細胞: 乳腺で二分化能を持つ幹細胞が果たす役割
がん: 白血病の前がん過程
分子生物学: RNA–タンパク質複合体の組み立て
宇宙: 非対称な爆発の残骸であるカシオペア座A
プラズマ物理学: 核融合の燃料利得向上
進化: 鳥類特有のものではなかった非潮汐的な換気
創薬: 関節リウマチ薬の標的を探す
細胞生物学: 半数体の生活に都合の良い調節戦略
目次
Editorials
Intelligent testing p.265
Science has a part to play in ensuring protection for defendants with intellectual disabilities.
doi: 10.1038/506265b
Helium high p.266
Many bemoan the shortage of helium for the lab, but for geologists, its true value is in the ground.
doi: 10.1038/506266a
News
Fight against smog ramps up p.273
Chinese government to provide incentives for heavy polluters to go green, but analysts question whether its wider air-quality strategy goes far enough.
doi: 10.1038/506273a
Missing galaxy mass found p.274
Gravitational lensing solves puzzle from the Big Bang’s echo.
doi: 10.1038/506274a
China plunges into ocean research p.276
Ambitious initiative targets Pacific currents, regional climate and deep-sea ecology.
doi: 10.1038/506276a
EU–Swiss research on shaky ground p.277
Vote for immigration quotas leads to suspension of talks over Horizon 2020 programme.
doi: 10.1038/506277a
Moon shots stuck on Earth p.278
Some Google Lunar X Prize contenders book launches for 2015 — but many say that is a stretch.
doi: 10.1038/506278a
Lone hunger striker spurs Nepal to action p.279
Country’s system of political patronage in science exposed.
doi: 10.1038/506279a
News Features
Astronomy: Death of a comet p.281
太陽に接近し、分解したアイソン彗星の最期を明らかにしようと、研究が続いている。
doi: 10.1038/506281a
Science in court: Smart enough to die? p.284
米国では、被告の知的能力が死刑判決の判断基準となっている州もあるが、その判断基準や、知的能力で評価することの妥当性について議論が巻き起こっている。
doi: 10.1038/506284a
News & Views
Astrophysics: Lopsided stellar death p.298
超新星の残骸であるカシオペア座Aの観測から、この星の爆発の中心に生じた過程について初めて調べられ、空間的な非対称性がこの爆発を説明するのに重要であるとする仮説が裏付けられた。
doi: 10.1038/506298a
Regenerative biology: Take the brakes off for liver repair p.299
血管内表面を覆っている内皮細胞が産生するタンパク質が、肝臓損傷後の細胞増殖を調節していることが分かり、さらに組織再生に血管シグナルが役割を持つことが実証された。
doi: 10.1038/506299a
Cancer: Persistence of leukaemic ancestors p.300
急性白血病の初期は、ほとんどの場合臨床的な症状が現れず、期間も短いと考えられている。だが、祖先となる前がん細胞は識別可能で、ずっと生き残るらしいことが今回明らかになった。
doi: 10.1038/nature13056
Plasma physics: A promising advance in nuclear fusion p.302
米国立点火施設で行われた実験により、核融合実験の進展を妨げてきた問題が解決され、世界中の核融合研究者を勇気づけることになった。
doi: 10.1038/nature13057
Molecular biology: Protein binding cannot subdue a lively RNA p.303
細胞のタンパク質合成機械であるリボソームは、決まった順序で構成成分から組み立てられる。今回、組み立ての最初の段階では動的な構造再編成に耐えなければならないことが明らかになった。
doi: 10.1038/nature13055
Ageing: Genetic rejuvenation of old muscle p.304
加齢が進むと、筋肉の再生に関わる幹細胞は可逆的な静止状態から非可逆的な老化状態へと切り替わる。老化の推進因子を標的とすれば、筋肉幹細胞を再び活動させることができ、筋肉再生が起こるようになる。
doi: 10.1038/nature13058
Review
The rise of oxygen in Earth’s early ocean and atmosphere p.307
How atmospheric oxygen concentrations evolved from only small amounts for the early Earth to about 21 per cent today remains uncertain; here our latest understanding of the evolution of Earth’s oxygen levels is discussed.
doi: 10.1038/nature13068
Articles
Geriatric muscle stem cells switch reversible quiescence into senescence p.316
This study shows that ageing satellite cells undergo an irreversible transition from a quiescent to a pre-senescent state that results in the loss of muscle regeneration in sarcopenia; furthermore, increased expression of p16INK4a is identified as a common feature of senescent satellite cells.
doi: 10.1038/nature13013
In situ identification of bipotent stem cells in the mammary gland p.322
Through the use of a novel three-dimensional imaging technique, used in conjunction with a multicolour reporter that allows lineage tracing and cell tracking of entire mammary ducts in vivo, bipotent stem cells are shown to have a central role in both puberty and long-term maintenance; in addition, long-lived luminal progenitor cells with a prominent role in ductal expansion are identified.
doi: 10.1038/nature12948
Identification of pre-leukaemic haematopoietic stem cells in acute leukaemia p.328
The authors identify pre-leukaemic haematopoietic stem cells (HSCs) in patients with acute myeloid leukaemia; these pre-leukaemic HSCs have the capacity of normal multi-lineage haematopoietic differentiation with a competitive growth advantage over wild-type HSCs, and owing to their persistence may serve as a reservoir for therapeutic resistance and relapse.
doi: 10.1038/nature13038
Protein-guided RNA dynamics during early ribosome assembly p.334
Three-colour fluorescence resonance energy transfer and molecular dynamics simulations are used to study the events occurring early in assembly of the 30S ribosome; within a non-native intermediate S4 ribosomal protein–16S RNA structure, S4 is capable of altering the RNA helix dynamics to facilitate conformation changes that enable subsequent protein binding.
doi: 10.1038/nature13039
Letters
Asymmetries in core-collapse supernovae from maps of radioactive 44Ti in Cassiopeia A p.339
The observation of non-uniformly distributed titanium emission in the interior of Cassiopeia A, a core-collapse supernova, is an indicator of asymmetries in the stellar explosion and provides strong evidence for the development of low-mode convective instabilities in such supernovae.
doi: 10.1038/nature12997
Fuel gain exceeding unity in an inertially confined fusion implosion p.343
Fusion fuel gains greater than unity — which are crucial to the generation of fusion energy — are achieved on the US National Ignition Facility using the ‘high-foot’ implosion method, which reduces instability in the implosion of the fuel.
doi: 10.1038/nature13008
Exceptional ballistic transport in epitaxial graphene nanoribbons p.349
Nanoribbons of graphene grown on electronics-grade silicon carbide conduct electrons much better than expected; at room temperature, the charge carriers travel through the nanoribbons without scattering for a surprisingly long distance, more than ten micrometres.
doi: 10.1038/nature12952
Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone p.355
The study of gas emission rates, chemistry and isotopic analyses show that the rate of helium-4 emission from the crust at Yellowstone is orders of magnitude greater than any conceivable rate of generation within the crust; this implies that helium has accumulated for hundreds of millions of years in deeper Archaean cratonic rocks, only to be liberated over the past two million years by crustal metamorphism induced by the Yellowstone hotspot.
doi: 10.1038/nature12992
Species coexistence and the dynamics of phenotypic evolution in adaptive radiation p.359
Increased trait differences among sympatric lineages of ovenbirds are explained by their greater evolutionary age compared with allopatric lineages.
doi: 10.1038/nature12874
Disease associations between honeybees and bumblebees as a threat to wild pollinators p.364
Laboratory infection experiments and field data show that emerging infectious diseases of honeybees are widespread infectious agents within the pollinator assemblage; the prevalence of deformed wing virus (DWV) and the parasite Nosema ceranae in honeybees and bumblebees is linked, and sympatric bumblebees and honeybees are infected by the same DWV strains, indicating ongoing disease transmission.
doi: 10.1038/nature12977
Unidirectional pulmonary airflow patterns in the savannah monitor lizard p.367
Unlike the tidal (in and out) breathing of mammals, bird lungs have unidirectional airflow patterns; here the savannah monitor lizard is shown to have unidirectional airflow too, with profound implications for the evolution of unidirectional airflow in reptiles, predating the origin of birds.
doi: 10.1038/nature12871
Landscape of genomic alterations in cervical carcinomas p.371
Whole-exome sequencing and analysis of 115 cervical carcinoma–normal paired samples, in addition to transcriptome and whole-genome sequencing for a subset of these tumours, reveal novel genes mutated at significant levels within this cohort and provide evidence that HPV integration is a common mechanism for target gene overexpression; results also compare mutational landscapes between squamous cell carcinomas and adenocarcinomas.
doi: 10.1038/nature12881
Genetics of rheumatoid arthritis contributes to biology and drug discovery p.376
A genome-wide association study meta-analysis of more than 100,000 subjects of European and Asian ancestries reveals 42 new risk loci for rheumatoid arthritis, with follow-up studies identifying 98 biological candidate genes that are either already being targeted by drugs or could be in the future.
doi: 10.1038/nature12873
Selection and evaluation of clinically relevant AAV variants in a xenograft liver model p.382
Chimaeric human–murine adeno-associated virus (AAV) capsids are described that transduce human primary hepatocytes more efficiently than currently used AAV vectors; the novel vectors may be good clinical candidates.
doi: 10.1038/nature12875
Convergent evolution of a fused sexual cycle promotes the haploid lifestyle p.387
In the predominantly diploid yeast Saccharomyces cerevisiae, regulatory control of mating is separate from meiosis; here the related hemiascomycete yeast Candida lusitaniae is shown to have coordinated regulatory control of mating and meiosis, favouring the formation of haploids.
doi: 10.1038/nature12891
Structure of a Naegleria Tet-like dioxygenase in complex with 5-methylcytosine DNA p.391
The Tet family of dioxygenase enzymes convert 5-methylcytosine to 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine, which has an effect on gene expression; here the structure of NgTet1, a Tet-like protein with the same activity as mammalian Tet1, is determined, showing that NgTet1 uses a base-flipping mechanism to access 5-methylcytosine.
doi: 10.1038/nature12905
