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.
The line between compliance and misconduct is finer than you might think.
Germany’s decision to slow the expansion of green-energy production is a reasonable move.
Network of deep-water observatories streams data in real time.
With drug companies’ policies hard to decipher, frustrated patients often resort to social-media campaigns and other public appeals.
Gold-mining boom in southeastern Amazon is driving high levels of mercury contamination.
Some admire project's ambition; others say that it hasn't justified its aims.
Government can't say how many policy studies it paid for or published, report reveals.
Jaw and teeth discovered in Indonesia are triumph for team that almost gave up hope.
India’s capital city scrambles to tackle its epic pollution problems.
Pieter Dorrestein uses mass spectrometry to eavesdrop on the molecular conversations between microbes and their world.
News & Views
Are the dynamics of our microbial communities unique to us or does everyone's microbiota follow the same rules? The emerging insights into this question could be of relevance to health and disease. See Letter p.259
The finding that an unusual iron oxide forms at extremely high pressures suggests that hydrogen and oxygen — two elements that strongly influence Earth's evolution — are generated in the mantle. See Letter p.241
Deadly coral snakes warn predators through striking red-black banding. New data confirm that many harmless snakes have evolved to resemble coral snakes, and suggest that the evolution of this Batesian mimicry is not always a one-way street.
The bacteria that inhabit the rodent gut promote insulin secretion and food intake by activating the parasympathetic nervous system — a hitherto unknown mode of action for this multifaceted microbiota. See Article p.213
Two molecular motors have been developed that use chemical energy to drive rotational motion in a single direction. The findings bring the prospect of devices powered by such motors a tantalizing step closer. See Letter p.235
New fossil findings demonstrate that the diminutive hominin Homo floresiensis lived on the Indonesian island of Flores at least 700,000 years ago, and may point to its rapid dwarfism from the larger Homo erectus. See Letters p.245 & p.249
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.
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.
A combination of optogenetic, electrophysiological and neuroanatomical tracing methods defines midbrain periaqueductal grey circuits for specific defensive behaviours.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The cultivation of Lenisia limosa, a newly discovered breviate protist, symbiotically colonized by relatives of the animal-associated bacterium Arcobacter.
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.
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.
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.
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.
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.
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.