Editorials
「ホビット」の発見場所の近くで新たに発見されたヒト族の化石は、ヒト族の系統が予想以上に複雑なことを示す証拠である。
Humanity’s forgotten family p.151
Hominin fossils discovered near the site of the 'hobbit' Homo floresiensis provide yet more evidence that the human lineage is more diverse than was ever imagined.
doi: 10.1038/534151a
ドイツが再生可能エネルギー生産の拡大速度の緩和を決断したのは、合理的だ。
Energy hit p.152
Germany’s decision to slow the expansion of green-energy production is a reasonable move.
doi: 10.1038/534152a
研究の不正と適正は、想像以上にほんの紙一重である。
Second chances p.152
The line between compliance and misconduct is finer than you might think.
doi: 10.1038/534152b
News
米国の海洋観測イニシアチブ(OOI)がようやく稼働し、大量のデータが。
Massive ocean-observing project launches — despite turmoil p.159
Network of deep-water observatories streams data in real time.
doi: 10.1038/534159a
米国では、未承認薬のコンパッショネート・ユースをより公正に行う方法を製薬企業が検討へ。
Fairer way to distribute last-ditch drugs gets real-world trial p.160
With drug companies’ policies hard to decipher, frustrated patients often resort to social-media campaigns and other public appeals.
doi: 10.1038/534160a
ペルーのゴールドラッシュが、水銀汚染による健康被害の引き金に。
Peru’s gold rush prompts public-health emergency p.162
Gold-mining boom in southeastern Amazon is driving high levels of mercury contamination.
doi: 10.1038/nature.2016.19999
米国の科学者たちが、ヒトの全ゲノムを一から合成しようという大胆な計画「Human Genome Project — Write」を発表。
Plan to synthesize human genome triggers mixed response p.163
Some admire project's ambition; others say that it hasn't justified its aims.
doi: 10.1038/nature.2016.20028
フローレス原人と近縁の化石が発見され、ヒト族の系統樹に新たな枝が。
‘Hobbit’ relatives found after ten-year hunt p.164
Jaw and teeth discovered in Indonesia are triumph for team that almost gave up hope.
doi: 10.1038/534164a
英国政府は委託した政策研究の費用や成果をきちんと把握していないと、批判が。
UK government slammed for losing track of its own research p.164
Government can't say how many policy studies it paid for or published, report reveals.
doi: 10.1038/nature.2016.20022
News Features
環境:デリーの致死的な大気
Can Delhi save itself from its toxic air? p.166
インドの首都デリーでは大気汚染が深刻化しており、改善のための対応に迫られている。
doi: 10.1038/534166a
微生物学:化学地図の製作者
The man who can map the chemicals all over your body p.170
カリフォルニア大学サンディエゴ校のPieter Dorresteinは、質量分析法を用いて、化学物質の分布から微生物の存在や関係を精密に描き出そうとしている。
doi: 10.1038/534170a
News & Views
宿主–微生物間相互作用:微生物相でのゲームの規則
Host-microbe interaction: Rules of the game for microbiota p.182
ヒト体内の微生物集団の動態は個人ごとに独自のものなのか、それとも全ての微生物相が同じ規則に従っているのだろうか。この問題について明らかになりつつある知見は健康や病気に関係してくると考えられる。
doi: 10.1038/534182a
地球化学:地球深部の水素と酸素
Geochemistry: Hydrogen and oxygen in the deep Earth p.183
極端な高圧条件下では異例な形の酸化鉄が生じることが分かり、地球の進化に強い影響を与える2つの元素、すなわち水素と酸素がマントル中で生じていることが示唆された。
doi: 10.1038/534183a
進化生物学:擬態に向かい、また後戻り
Evolutionary biology: To mimicry and back again p.184
致死的な毒を持つサンゴヘビは、赤と黒のしま模様という目立つ体色パターンで捕食者に警告する。多くの無害なヘビがサンゴヘビに似るように進化したことが新たな研究により確認された。また、このベイツ型擬態への進化は、一方通行ばかりではないことが示唆された。
doi: 10.1038/nature18441
生理学:微生物が脳へ送るシグナルが体重を制御する
Physiology: Microbial signals to the brain control weight p.185
齧歯類の腸内に生息している細菌は、副交感神経系を活性化させてインスリン分泌と食物摂取を促進することが分かった。微生物相は多様な役割を持つが、これはこれまで知られていなかった新しい作用である。
doi: 10.1038/534185a
化学:逆回転しない分子モーター
Chemistry: No turning back for motorized molecules p.187
化学エネルギーを使って一方向の回転運動をする2種類の分子モーターが開発された。この成果は、こうしたモーターで動くデバイスへの期待をいやが上にも高めるものだ。
doi: 10.1038/534187a
古人類学:フローレス原人の出現
Palaeoanthropology: The dawn of Homo floresiensis p.188
小型のヒト族であるフローレス原人(Homo floresiensis)は、インドネシアのフローレス島に少なくとも70万年前には生息していたことが、新たに見つかった化石によって実証された。これは、もっと大型のホモ・エレクトスからの小型化が迅速に進行したことを示しているのかもしれない。
doi: 10.1038/534188a
Perspective
微生物群集:実験科学で宿主–マイクロバイオーム相互作用を考慮する
Accounting for reciprocal host–microbiome interactions in experimental science p.191
This work highlights the critical challenges in experimental design and interpretation due to important combinatorial effects of host and microbial genes, and calls for the development of minimal reporting requirements to improve the interpretation and reproducibility of experimental biology.
doi: 10.1038/nature18285
Articles
集団遺伝学:氷期のヨーロッパの遺伝学的歴史
The genetic history of Ice Age Europe p.200
Analysis of ancient genomic data of 51 humans from Eurasia dating from 45,000 to 7,000 years ago provides insight into the population history of pre-Neolithic Europe and support for recurring migration and population turnover in Europe during this period.
doi: 10.1038/nature17993
神経科学:防御行動を生み出す中脳の回路
Midbrain circuits for defensive behaviour p.206
A combination of optogenetic, electrophysiological and neuroanatomical tracing methods defines midbrain periaqueductal grey circuits for specific defensive behaviours.
doi: 10.1038/nature17996
メタボリックシンドローム:酢酸はマイクロバイオーム–脳–β細胞系を介してメタボリックシンドロームを促進する
Acetate mediates a microbiome–brain–β-cell axis to promote metabolic syndrome p.213
Increased acetate production by an altered gut microbiota in rats fed a high-fat diet activates the parasympathetic nervous system, which in turn promotes increased insulin secretion, increased food intake, obesity and related changes.
doi: 10.1038/nature18309
Letters
宇宙物理学:活動的な超大質量ブラックホールへ落ち込む低温で塊状の降着
Cold, clumpy accretion onto an active supermassive black hole p.218
The so-called accretion flow that powers the growth of supermassive black holes in galaxy centres is assumed to be dominated by a smooth, steady flow of very hot plasma, but now observations instead reveal a clumpy accretion of very cold molecular clouds onto a supermassive black hole in the nucleus of a nearby giant elliptical galaxy.
doi: 10.1038/nature17969
量子情報:超伝導回路によるディジタル化断熱量子計算
Digitized adiabatic quantum computing with a superconducting circuit p.222
A digitized approach to adiabatic quantum computing, combining the generality of the adiabatic algorithm with the universality of the digital method, is implemented using a superconducting circuit to find the ground states of arbitrary Hamiltonians.
doi: 10.1038/nature17658
材料科学:準安定高エントロピー二相合金は強度と延性のトレードオフを解決する
Metastable high-entropy dual-phase alloys overcome the strength–ductility trade-off p.227
Metals have been mankind’s most essential materials for thousands of years; however, their use is affected by ecological and economical concerns. Alloys with higher strength and ductility could alleviate some of these concerns by reducing weight and improving energy efficiency. However, most metallurgical mechanisms for increasing strength lead to ductility loss, an effect referred to as the strength–ductility trade-off. Here we present a metastability-engineering strategy in which we design nanostructured, bulk high-entropy alloys with multiple compositionally equivalent high-entropy phases. High-entropy alloys were originally proposed to benefit from phase stabilization through entropy maximization. Yet here, motivated by recent work that relaxes the strict restrictions on high-entropy alloy compositions by demonstrating the weakness of this connection, the concept is overturned. We decrease phase stability to achieve two key benefits: interface hardening due to a dual-phase microstructure (resulting from reduced thermal stability of the high-temperature phase); and transformation-induced hardening (resulting from the reduced mechanical stability of the room-temperature phase). This combines the best of two worlds: extensive hardening due to the decreased phase stability known from advanced steels and massive solid-solution strengthening of high-entropy alloys. In our transformation-induced plasticity-assisted, dual-phase high-entropy alloy (TRIP-DP-HEA), these two contributions lead respectively to enhanced trans-grain and inter-grain slip resistance, and hence, increased strength. Moreover, the increased strain hardening capacity that is enabled by dislocation hardening of the stable phase and transformation-induced hardening of the metastable phase produces increased ductility. This combined increase in strength and ductility distinguishes the TRIP-DP-HEA alloy from other recently developed structural materials. This metastability-engineering strategy should thus usefully guide design in the near-infinite compositional space of high-entropy alloys.
doi: 10.1038/nature17981
電気化学:強相関ペロブスカイト燃料電池
Strongly correlated perovskite fuel cells p.231
A fundamentally different approach to designing solid oxide electrolytes is presented, using a phase transition to suppress electronic conduction in a correlated perovskite nickelate; this yields ionic conductivity comparable to the best-performing solid electrolytes in the same temperature range.
doi: 10.1038/nature17653
ナノテクノロジー:化学燃料で動く自律型小分子モーター
An autonomous chemically fuelled small-molecule motor p.235
A system is described in which a small macrocycle is continuously transported directionally around a cyclic molecular track when powered by irreversible reactions of a chemical fuel; such autonomous chemically fuelled molecular motors should find application as engines in molecular nanotechnology.
doi: 10.1038/nature18013
地球化学:下部マントル深部条件におけるFeO2とFeOOH、および地球の酸素水素循環
FeO2 and FeOOH under deep lower-mantle conditions and Earth’s oxygen–hydrogen cycles p.241
First-principles calculations and experiments are used to identify a stable, pyrite-structured iron oxide at 76 gigapascals and 1,800 kelvin that holds an excessive amount of oxygen and to show that goethite (rust) decomposes under these deep lower-mantle conditions to form an iron oxide and release hydrogen; this process provides another way to interpret the origin of seismic and geochemical anomalies in the deep lower mantle of Earth.
doi: 10.1038/nature18018
古人類学:フローレス島の中期更新世前期のフローレス原人様化石
Homofloresiensis-like fossils from the early Middle Pleistocene of Flores p.245
The evolutionary origin of Homo floresiensis, a diminutive hominin species previously known only by skeletal remains from Liang Bua in western Flores, Indonesia, has been intensively debated. It is a matter of controversy whether this primitive form, dated to the Late Pleistocene, evolved from early Asian Homo erectus and represents a unique and striking case of evolutionary reversal in hominin body and brain size within an insular environment. The alternative hypothesis is that H. floresiensis derived from an older, smaller-brained member of our genus, such as Homo habilis, or perhaps even late Australopithecus, signalling a hitherto undocumented dispersal of hominins from Africa into eastern Asia by two million years ago (2 Ma). Here we describe hominin fossils excavated in 2014 from an early Middle Pleistocene site (Mata Menge) in the So’a Basin of central Flores. These specimens comprise a mandible fragment and six isolated teeth belonging to at least three small-jawed and small-toothed individuals. Dating to ~0.7 Ma, these fossils now constitute the oldest hominin remains from Flores. The Mata Menge mandible and teeth are similar in dimensions and morphological characteristics to those of H. floresiensis from Liang Bua. The exception is the mandibular first molar, which retains a more primitive condition. Notably, the Mata Menge mandible and molar are even smaller in size than those of the two existing H. floresiensis individuals from Liang Bua. The Mata Menge fossils are derived compared with Australopithecus and H. habilis, and so tend to support the view that H. floresiensis is a dwarfed descendent of early Asian H. erectus. Our findings suggest that hominins on Flores had acquired extremely small body size and other morphological traits specific to H. floresiensis at an unexpectedly early time.
doi: 10.1038/nature17999
古人類学:フローレス島における既知で最古のヒト族化石の年代と背景
Age and context of the oldest known hominin fossils from Flores p.249
Stratigraphic, chronological, environmental and faunal context are provided to the newly discovered fossils of hominins that lived in the So’a Basin in Flores, Indonesia, 700,000 years ago; the stone tools recovered with the fossils are similar to those associated with the much younger Homo floresiensis from Flores, discovered in Liang Bua to the west.
doi: 10.1038/nature17663
微生物学:環境中のブレヴィアータ綱生物には表在生物である相利共生菌Arcobacterが共生している
Environmental Breviatea harbour mutualistic Arcobacter epibionts p.254
The cultivation of Lenisia limosa, a newly discovered breviate protist, symbiotically colonized by relatives of the animal-associated bacterium Arcobacter.
doi: 10.1038/nature18297
微生物群集:ヒトの微生物動態の普遍性
Universality of human microbial dynamics p.259
A new computational method to characterize the dynamics of human-associated microbial communities is applied to data from two large-scale metagenomic studies, and suggests that gut and mouth microbiomes of healthy individuals are subjected to universal (that is, host-independent) dynamics, whereas skin microbiomes are shaped by the host environment; the method paves the way to designing general microbiome-based therapies.
doi: 10.1038/nature18301
微生物群集:双生児とノトバイオートマウスにおける腸内微生物相および粘膜IgA応答の発達
Development of the gut microbiota and mucosal IgA responses in twins and gnotobiotic mice p.263
The relationship between assembly of the gut community and gut mucosal immunoglobulin A responses during the first 24–36 months of postnatal life in a cohort of 40 twin pairs is defined and modelled in gnotobiotic mice.
doi: 10.1038/nature17940
医学研究:ブラジルのジカウイルス系統は実験モデルで先天異常を引き起こす
The Brazilian Zika virus strain causes birth defects in experimental models p.267
The Zika virus can cross the placenta and cause intrauterine growth restriction, including microcephaly, in the SJL strain of mice; the virus can also infect human brain organoids, inducing cell death by apoptosis and disrupting cortical layers.
doi: 10.1038/nature18296
がん治療:新世代mTOR阻害剤によりmTORの耐性変異を克服する
Overcoming mTOR resistance mutations with a new-generation mTOR inhibitor p.272
Inhibitors of the mTOR kinase are in clinical trials for the treatment of cancer; here, mutations in mTOR that can lead to drug resistance are investigated and the results are used to design a new class of mTOR inhibitors that can overcome this resistance.
doi: 10.1038/nature17963
分子生物学:緊縮調節のリボソーム依存性活性化
Ribosome-dependent activation of stringent control p.277
The structure of a bacterial ribosome–RelA complex reveals that RelA, a protein recruited to the ribosome in the case of scarce amino acids, binds in a different location to translation factors, and that this binding event suppresses auto-inhibition to activate synthesis of the (p)ppGpp secondary messenger, thus initiating stringent control.
doi: 10.1038/nature17675
構造生物学:超高分解能0.48 Åでの鉄硫黄タンパク質の電荷密度解析
Charge-density analysis of an iron–sulfur protein at an ultra-high resolution of 0.48 Å p.281
The fine structures of proteins, such as the positions of hydrogen atoms, distributions of valence electrons and orientations of bound waters, are critical factors for determining the dynamic and chemical properties of proteins. Such information cannot be obtained by conventional protein X-ray analyses at 3.0–1.5 Å resolution, in which amino acids are fitted into atomically unresolved electron-density maps and refinement calculations are performed under strong restraints. Therefore, we usually supplement the information on hydrogen atoms and valence electrons in proteins with pre-existing common knowledge obtained by chemistry in small molecules. However, even now, computational calculation of such information with quantum chemistry also tends to be difficult, especially for polynuclear metalloproteins. Here we report a charge-density analysis of the high-potential iron–sulfur protein from the thermophilic purple bacterium Thermochromatium tepidum using X-ray data at an ultra-high resolution of 0.48 Å. Residual electron densities in the conventional refinement are assigned as valence electrons in the multipolar refinement. Iron 3d and sulfur 3p electron densities of the Fe4S4 cluster are visualized around the atoms. Such information provides the most detailed view of the valence electrons of the metal complex in the protein. The asymmetry of the iron–sulfur cluster and the protein environment suggests the structural basis of charge storing on electron transfer. Our charge-density analysis reveals many fine features around the metal complex for the first time, and will enable further theoretical and experimental studies of metalloproteins.
doi: 10.1038/nature18001