This press release contains:
· Summaries of newsworthy papers:
Genetics: ‘Natural’ protection against Alzheimer’s disease
Genomics: Reconstructing Native American population history
Genomics: Banana genome unpeeled
Neuroscience: How the brain plays hunger games
Comment: Shore up unregulated health markets
Materials science: Self-regulating materials with SMARTS
Neuroscience: Protecting nerve cells against neurodegeneration
Genomics: Sequencing a whole genome from 10 to 20 cells
Physics: When is a metal not a metal?
Physics: Hot ways to generate spin voltage
And finally... Avoiding that sinking feeling
· Geographical listing of authors
[1] Genetics: ‘Natural’ protection against Alzheimer’s disease (AOP)
DOI: 10.1038/nature11283
The discovery of a genetic mutation that protects against both Alzheimer’s disease and age-related cognitive decline, reported in Nature this week, raises the possibility that the two conditions may be mechanistically related. This mutation could possibly represent a target for treatments to prevent Alzheimer’s disease.
A hallmark of Alzheimer’s disease is the existence of amyloid plaques, the formation of which involves the amyloid precursor protein (APP). By screening almost 2,000 genomes, Kari Stefansson and co-workers identify a specific coding mutation in the APP gene that confers strong protection against Alzheimer’s disease. This mutation, although rare itself, results in an approximately 40% reduction in the formation of plaque proteins. The authors also find that elderly individuals (aged between 80 and 100 years) without Alzheimer’s disease who carry this mutation have better cognitive function than those without the mutation. They propose that Alzheimer’s disease may represent the extreme of the age-related decline in cognitive function.
Mutations in the APP gene have been implicated in familial, early-onset disease, but had not been linked to the common, late-onset form of Alzheimer’s disease. Stefansson and colleagues comment that their findings support previous ideas that interfering with APP cleavage, which can be achieved with existing small-molecule drugs, may protect against Alzheimer’s disease.
CONTACT
Kari Stefansson (deCODE genetics, Reykjavik, Iceland)
Tel: +354 570 1900; E-mail: [email protected]
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[2] Genomics: Reconstructing Native American population history (AOP)
DOI: 10.1038/nature11258
Research comparing 52 Native American populations along with 17 Siberian populations provides insight into migrations within the New World and is published online in Nature this week. David Reich and colleagues’ data suggest that the controversial hypothesis that the Americas were peopled in three migration waves may be true.
The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research, and many questions remain unsolved. One contentious issue is whether the settlement occurred via a single or multiple streams of migration from Siberia. Reich and co-workers genotyped 364,470 single nucleotide polymorphisms in 69 populations. They show that Native Americans descend from at least three streams of Asian gene flow. Most descend from a single ancestral population that they call ‘First American’, but speakers of Eskimo–Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow. The Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third wave. In future, further insights might be gained from whole-genome sequences and data from the many populations in the Americas that do not self-identify as native.
CONTACT
David Reich (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 432 6548; E-mail: [email protected]
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[3] Genomics: Banana genome unpeeled (AOP)
DOI: 10.1038/nature11241
Sequencing and analysis of the banana genome, an important staple food in many countries and a major source of income, are reported in Nature. The results offer insights into plant evolutionary relationships and genome evolution, and provide a resource for future genetic improvement of this crop species. The banana is the fist non-grass monocotyledon (a major group of flowering plants) to have its genome sequenced.
Angélique D’Hont and colleagues produced a reference genome sequence of a major banana cultivar called Musa acuminate, providing a resource for understanding the complex genetics of this crop. For example, they find that this lineage of bananas has undergone three rounds of whole genome duplication, which has played a major role in genome evolution. Having access to this information may help to identify genes responsible for important characteristics, such as fruit quality and pest resistance, the authors note. They conclude that the Musa genome sequence provides a crucial stepping-stone for plant gene and genome evolution studies, and may represent an important advance towards securing food supplies from new generations of Musa crops.
CONTACT
Angélique D’Hont (CIRAD, Montpellier, France)
Tel: +33 4 67 61 59 27; E-mail: angelique.d’[email protected]
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[4] Neuroscience: How the brain plays hunger games (AOP)
DOI: 10.1038/nature11270
Processes in the brain that potentially control hunger, feeding behaviour and pathways associated with overeating disorders are identified in Nature this week. A particular neural circuit is shown to have a critical role in stimulating feeding in mice. Understanding how interactions between neurons affect feeding behaviours could be used to explore therapeutic approaches to overeating conditions.
To examine the neural processes that underlie hunger, Scott Sternson and colleagues investigated neural circuits of AGRP neurons, a population of brain cells that are active in a starvation state. They show that AGRP neuron interactions with different neurons produce distinct outcomes in mice, some of which do not affect feeding behaviour. However, intense eating is induced when AGRP neurons suppress oxytocin-releasing neurons; this population of neurons is absent in patients with Prader–Willi syndrome, a condition involving insatiable hunger. The authors conclude that the connectivity between these two neuron populations has an important role in regulating hunger behaviours.
CONTACT
Scott Sternson (Howard Hughes Medical Institute, Ashburn, VA, USA)
Tel: +1 571 209 4103; E-mail: [email protected]
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Comment: Shore up unregulated health markets (pp 163-165)
In Africa and Asia, many people buy their own medicines and seek health care from providers who are
informally trained. Patients may receive drugs that they don’t need or that don’t work ― with antibiotics in particular being widely overprescribed. These unregulated markets are a major cause of concern for global public health that is going unrecognized by the World Health Organization, argue health-systems experts David Peters and Gerald Bloom in a Comment piece in this week’s Nature.
The rapid expansion of health markets in Asia and Africa has made medicines, information and primary-care services available in all but the most remote areas. But it also creates problems with drug safety and efficiency, equity of treatment and the cost of care. Village doctors and midwives often prescribe unnecessary pills or injections, with patients bearing the expense and the costs to their health. Counterfeit drugs are rife and drug resistance is growing. To meet the health and welfare needs of the poor, we need to understand and improve how these evolving markets operate, the authors write. Following the example of China, which reached out to village doctors in 2003 to address the SARS epidemic, governments, citizen groups and companies can build partnerships with local providers to support innovation and improve the delivery of safe, effective and affordable treatments for common conditions.
CONTACT
David Peters (Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA)
Tel: +1 410 955 3928; E-mail: [email protected]
Gerald Bloom (University of Sussex, Brighton, UK)
Tel: +44 1273 915667; E-mail: [email protected]
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[5] Materials science: Self-regulating materials with SMARTS (pp 214-218)
Self-regulating, self-powered materials that may have potential applications for controlling the temperature in energy-efficient ‘smart’ buildings are described in this week’s Nature. The materials can respond rapidly to maintain conditions, in this case temperature, within a pre-defined range.
Inspired by the ability of living organisms to maintain tight control of their local environment through a process called homeostasis, Joanna Aizenberg and colleagues design a method to produce synthetic homeostatic materials. Their system is made of two layers: a temperature-responsive gel layer that can control the entry of catalyst-decorated microstructures buried within the gel into a second reactant layer. An exothermic chemical reaction in the second layer occurs depending on the presence or absence of the catalyst and serves as a highly precise on/off switch. The researchers thus achieve a continuous feedback loop between the exothermic chemical reaction in the second layer and the mechanical action of the temperature-responsive gel in the first layer, maintaining artificial homeostasis.
The authors suggest that their self-regulated mechano-chemical adaptively reconfigurable tunable system (SMARTS) could be tailored to modulate light, pH, glucose, pressure, oxygen and many other physical, chemical, and biochemical conditions. They anticipate that SMARTS could be used in many fields, such as robotics, biomedical engineering and architecture.
CONTACT
Joanna Aizenberg (Harvard University, Cambridge, MA, USA)
Tel: +1 617 495 3558; E-mail: [email protected]
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[6] Neuroscience: Protecting nerve cells against neurodegeneration (AOP)
DOI: 10.1038/nature11314
How a group of non-neuronal cells called oligodendroglia protect neurons and their long axons against neurodegeneration is explained in Nature this week. Oligodendroglia form part of the central nervous system and provide a protective coat, known as a myelin sheath, for axons. This study finds that these cells also support neurons by supplying them with energy; disruption of this supply leads to axon dysfunction and ultimately to neuron degeneration.
Abnormal or impaired function in oligodendroglia leads to axon degeneration in several human diseases, such as multiple sclerosis. A lack of energy metabolites has been proposed as a cause of this degeneration, an idea that is supported by evidence from Jeffrey Rothstein and colleagues. The authors report that oligodendroglia posses a transporter for the energy metabolite lactate, and seem to be the prime supplier of lactate to axons and neurons. Disruption of this transporter is shown to result in axon damage and neuron loss in animal and cell culture models.
The same transporter is found to be reduced in patients with — and in mouse models of — amyotrophic lateral sclerosis (ALS), a form of neurodegeneration, indicating a role for the transporter in disease development.
CONTACT
Jeffrey Rothstein (The Johns Hopkins University, Baltimore, MD, USA)
Tel: +1 410 614 5972; E-mail: [email protected]
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[7] Genomics: Sequencing a whole genome from 10 to 20 cells (pp 190-195)
A method that can generate haplotypes and enable cost-effective and accurate sequencing of human genomes from only a few human cells is reported in this week’s Nature. The technique has implications for various clinical applications, such as the genetic screening of tissue biopsies or pre-implantation embryos generated from in vitro fertilization.
Despite recent advances in whole-genome sequencing technology, most current methods lack the clinical accuracy and ability to describe the genomic context (haplotypes), in which variants occur on each individual chromosome, in a cost-effective manner. Radoje Drmanac and colleagues present an approach termed long fragment read (LFR) technology, which can sequence a whole genome from 10 to 20 cells. LFR technology relies on methods similar to those used to sequence long single DNA molecules, but without the need to clone or separate the condensed and coiled chromosomes. The authors report that LFR can accurately detect 97% of heterozygous single nucleotide variants in the genome, yielding a better understanding of the clinical implications of genomic variations.
CONTACT
Radoje Drmanac (Complete Genomics Inc., Mountain View, CA, USA)
Tel: +1 650 943 2833; E-mail: [email protected]
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[8] Physics: When is a metal not a metal? (AOP)
DOI: 10.1038/nature11231
The transition from insulating to metallic behaviour in a material with strong electron correlations, an important problem in electronic materials, is probed using an innovative technique described in Nature this week. Direct, time-resolved observations of changes in a transition metal oxide allow measurement of the intrinsic dynamics and mechanism underlying the phase transition.
Richard Averitt and colleagues use ultrafast terahertz (THz) pulses to induce a phase transition in vanadium dioxide and a metamaterial structure deposited on the transition metal oxide plays a dual role in amplifying the pulses and enabling macroscopic detection of the local changes in vanadium dioxide. The direct, time-resolved observation of the dynamics of the electric-field-driven transition allows the researchers to deduce a detailed microscopic picture underlying the structural and electronic change. The authors conclude that their technique is versatile and could even be used to study phase transitions in superconductors.
CONTACT
Richard Averitt (Boston University, Boston, MA, USA)
Tel: +1 617 353 2619; E-mail: [email protected]
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[9] Physics: Hot ways to generate spin voltage (pp 210-213; N&V)
An effect that generates a voltage for spin-polarized electrons using a temperature gradient achieves values comparable to the highest observed signals for conventional thermoelectrics, where electric voltages are generated. This so-called giant spin Seebeck effect, reported in this week’s Nature, is observed in a non-magnetic material, and is much greater than spin Seebeck effects previously seen in magnetic materials. These results may boost the prospects for spintronics, a field of electronics that takes advantage of the spin properties of electrons, with the potential to improve the efficiency of electronic devices.
The discovery of the spin Seebeck effect in ferromagnets in 2008 opened up a whole new line of research in spintronics, although the observed effect was small. Joseph Heremans and colleagues demonstrate a much larger effect in an indium antimonide semiconductor, which is non-magnetic. Their findings indicate that the spin Seebeck effect relies only on spin polarization, not on magnetic exchange as previously thought. The authors suggest the work points to ways of optimizing all spin-thermal devices.
CONTACT
Joseph Heremans (The Ohio State University, Columbus, OH, USA)
Tel (until 11 July): +41 79 866 0901; E-mail: [email protected]
Tero Heikkila (Aalto University, Finland) N&V author
Tel: +358 503 442 469; E-mail: [email protected]
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[10] And finally... Avoiding that sinking feeling (pp 205-209; N&V)
The forces that can allow a person to walk over quicksand without sinking, provided they move fast enough, are described in Nature this week. Quicksand is an example of a ‘non-Newtonian fluid’ — a liquid (often a suspension of particles) that changes its properties as it flows: in this case, one that can harden under impact. The dynamics of this process have been caught in the act by researchers imaging a rod striking a solution of cornstarch in water.
No single mechanism has provided an explanation of how dense suspensions can generate stresses so large under impact (such as a foot striking quicksand) that a person could run across the liquid without sinking. Shear thickening (a tendency of the sheared fluid to dilate) is often invoked to explain the temporary hardening of the liquid, but Scott Waitukaitis and Heinrich Jaeger demonstrate that the remarkable impact resistance is produced by a different mechanism. The resistance instead emerges from a process where particles jam together causing the liquid to temporarily solidify, which the authors describe as being similar to what happens when a plough is pushed into loose snow. The authors conclude that localised jamming of particles, which rapidly spreads upon impact, determines the initial mechanical response.
CONTACT
Scott Waitukaitis (The University of Chicago, IL, USA)
Tel: +1 773 702 6075; E-mail: [email protected]
Martin van Hecke (Leiden University, Netherlands) N&V author
Tel: +31 71 527 5482; E-mail: [email protected]
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ALSO IN THIS ISSUE…
[11] Anhedonia requires MC4R-mediated synaptic adaptations in nucleus accumbens (pp 183-189)
[12] Watching DNA polymerase η make a phosphodiester bond (pp 196-201; N&V)
[13] Deglacial rapid sea level rises caused by ice-sheet saddle collapses (pp 219-222)
[14] Protein activity regulation by conformational entropy
DOI: 10.1038/nature11271
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GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
ARGENTINA
Buenos Aires: 2
La Plata: 2
AUSTRALIA
Yarralumla: 3
BOLIVIA
Potosı: 2
BRAZIL
Curitiba: 2
Porto Alegre: 2
CANADA
Montréal: 2
CHILE
Arica: 2
CHINA
Hangzhou: 12
Hong Kong: 2
COLOMBIA
Medellın: 2
Santa Marta: 2
COSTA RICA
San José: 2
CZECH REPUBLIC
Olomouc: 3
FINLAND
Helsinki: 1
FRANCE
Capesterre-Belle-Eau: 3
Evry: 3
Gif-sur-Yvette: 3
Marseille: 2
Montpellier: 3
Perpignan: 3
Toulouse: 2
GERMANY
Tübingen: 1
GUATEMALA
Ciudad de Guatemala: 2
ICELAND
Reykjavik: 1
JAPAN
Kumamoto: 12
MÉXICO
Mérida Yucatán: 2
México City: 2
NETHERLANDS
Wageningen: 3
NORWAY
Oslo: 1
PERU
Lima: 2
RUSSIA
Novosibirsk: 2
Yakutsk: 2
SPAIN
Santiago de Compostela: 2
SWEDEN
Stockholm: 1
Uppsala: 7
SWITZERLAND
Bern: 2
Geneva: 2
Lausanne: 2, 6
Zurich: 3
UNITED KINGDOM
Bristol: 13
Leicester: 3
London: 2
UNITED STATES OF AMERICA
Arizona
Tucson: 3
California
Berkeley: 2, 3
Los Angeles: 2
Mountain View: 7
San Jose: 7
South San Francisco: 1
Stanford: 11
Connecticut
New Haven: 2
Georgia
Athens: 3
Illinois
Chicago: 2, 10
Maryland
Baltimore: 6
Bethesda: 12
Massachusetts
Boston: 2, 7, 8
Cambridge: 2, 5, 7, 8
Medford: 8
New Jersey
Piscataway: 14
Ohio
Columbus: 9
Pennsylvania
Pittsburgh: 5
Virginia
Ashburn: 4
Charlottesville: 8
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PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]<mailto:[email protected]>
From Japan, Korea, China, Singapore and Taiwan
Eiji Matsuda, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]<mailto:[email protected]>
From the UK
Rebecca Walton, Nature London
Tel: +44 20 7843 4502; E-mail: [email protected]<mailto:[email protected]>
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