This press release contains:
---Summaries of newsworthy papers:
Astrophysics: Unlucky star swallowed by supermassive black hole
News and Comment: What makes a modern human
Ecology: Plant responses to climate change
Neurodegenerative disease: New thoughts on Alzheimer disease development
Geoscience: Composition of the lower mantle
And finally... Species variety is the spice of life
---Geographical listing of authors
-----------------------------------------------------------------------
[1] Astrophysics: Unlucky star swallowed by supermassive black hole (AOP; N&V)
DOI: 10.1038/nature10990
Observations of a star being sucked into a supermassive black hole are reported in Nature this week. The data allow the mass and type of the ill-fated star and the timing of this event to be determined.
Suvi Gezari and colleagues recount the discovery of a flare of radiation from a star being torn apart and consumed by a supermassive black hole. The flare was first seen in May 2010, peaked in July, and subsequently declined in September 2010. Analysis of this light curve allows the time of disruption to be determined to an accuracy of two days. The authors use their observations to model the mass and radius of the disrupted star, which in turn enables them to calculate the mass of the black hole. In addition, they constrain the properties of the star to that of a helium-rich stellar core.
Flares of radiation from the tidal disruption of stars as described here act as markers for supermassive black holes that otherwise lie dormant in the centres of distant galaxies. However, these events are rare and often only the tail end is seen, which hampers attempts to ascertain the timing of the event and the type of star disrupted.
CONTACT
Suvi Gezari (Johns Hopkins University, Baltimore, MD, USA)
Tel: +1 410 516 3462; E-mail: [email protected]
Giuseppe Lodato (Università degli Studi di Milano, Italy) N&V author
Tel: +39 2 5031 7449; E-mail: [email protected]
---
News and Comment: What makes a modern human (pp 23-35)
Most of us carry genes from archaic species such as Neanderthals or Denisovans. In a Comment piece in this week’s Nature, Chris Stringer explains why the DNA we have in common is more important than any differences. The article is part of a special focus on humanity’s early migrations.
Recent DNA evidence has shown that after modern humans left Africa around 60,000 years ago, they bred for a short period of time with archaic humans ― and, as a result, some humans living today have more archaic genes than others. It is possible that these genes may help to explain how and when regional variation developed in Homo sapiens. A concern is the idea that those with alternative agendas may try to use these new data to speculate about whether some groups are less ‘modern’ than others.
To steer the discussions in a positive direction, Stringer asserts that the term modern humans, by definition, equally describes all humans living today. Some of us may have more DNA from archaic populations than others, but the great majority of our genes, morphology and behaviour derive from our common African heritage. “And what unites us should take precedence over that which distinguishes us from each other,” he writes.
The special issue also includes three News Features, which explore when and how modern humans expanded beyond their African birthplace. Discoveries in Arabia, Europe, and the Americas all suggest that humanity colonized the planet earlier than was thought.
CONTACT
Chris Stringer (Natural History Museum, London, UK)
Tel: +44 207 942 5539; E-mail: [email protected]
This author can also be contacted via Claire Gilby in the Natural History Museum press office:
Tel: +44 207 942 5106; E-mail: [email protected]
For background information on the News Features, please contact the Nature press office.
---
[2] Ecology: Plant responses to climate change (AOP)
DOI: 10.1038/nature11014
Experimental studies investigating plant reactions to warming may have underpredicted shifts in plant life cycles, a study published in Nature suggests. Thus, predicted responses of plants to climate change based on experimental data may need to be re-evaluated. Such responses can affect entire food webs and can alter nutrient cycling and water supply.
Plant growth, flowering and leafing times are shifting in response to climate change, but studies differ in their assessment of by how much. Elizabeth Wolkovich and colleagues present a meta-analysis comparing experimental warming studies and long-term observations of variation in plant life cycles. They find that overall the experimental studies underpredict the advances in flowering and leafing times that are seen in the observational studies by 8.5 times and 4 times, respectively. Improvements to experimental designs may be needed to predict better how plants will react to climate change, the authors conclude.
CONTACT
Elizabeth Wolkovich (University of California – San Diego, La Jolla, CA, USA)
E-mail: [email protected]
---
[3] Neurodegenerative disease: New thoughts on Alzheimer disease development (AOP)
DOI: 10.1038/nature11060
Novel insights about the molecular basis of Alzheimer disease development are presented in Nature this week. Experiments in mice and in cultured brain cells show how a peptide called pyroglutamylated (pE) beta amyloid (Aβ) may induce Alzheimer disease. This peptide is a modified version of the Aβ peptides that form the plaques commonly associated with Alzheimer disease.
Previous studies have shown that a pE-Aβ is associated with initiation of Alzheimer disease, but a mechanistic explanation of this has been lacking. George Bloom and colleagues show that pE-Aβ together with Aβ1-42 forms oligomers (multi-unit molecules) that are much more toxic than those made from Aβ1-42 alone. They discover that these oligomers propagate via prion-like processes involving protein misfolding, and can inhibit neuronal activity in brain cells cultures. These pE-Aβ-containing oligomers can cause neuronal loss in mice, but not in the absence of a protein called tau. This finding indicates that expression of tau, a protein implicated in Alzheimer disease, is needed for toxicity.
The authors identified similar oligomers in the brains of three humans with Alzheimer disease, which they suggest supports the proposed role for pE-Aβ in disease propagation.
CONTACT
George Bloom (University of Virginia, Charlottesville, VA, USA)
Tel: +1 434 243 3543; E-mail: [email protected]
---
[4] Geoscience: Composition of the lower mantle (pp 90-94; N&V)
Sound waves are used to better constrain the chemical composition of the Earth’s lower mantle, a long-standing challenge in Earth science, in a study published in this week’s Nature. The results imply that the lower mantle contains more silicon than the upper mantle.
Whereas the composition of the upper mantle has been largely established from samples brought to the surface, the composition of the lower mantle has been more difficult to constrain. To address this issue, Motohiko Murakami and co-workers have made laboratory measurements of sound waves moving through different minerals at pressure and temperature conditions matching those of the lower mantle. They compare these data with seismic data and determine that more than 93% of the lower mantle seems to be made of a mineral called perovskite. These findings suggest that the lower mantle is highly enriched with silicon compared with the upper mantle.
The authors suggest that their results may account for the ‘missing silicon’ problem that has blighted models of Earth’s composition. Such models have compared the composition of meteorites with that of the Earth, but found that if the entire mantle had the composition of the upper mantle, the Earth would be depleted in silicon, compared to meteorites, which are thought to represent the left-over building blocks of the Earth.
CONTACT
Motohiko Murakami (Tohoku University, Sendai, Japan)
Tel: +81 22 795 6662; E-mail: [email protected]
Ian Jackson (Australian National University, Canberra, Australia) N&V author
Tel: +61 2 6125 2498; E-mail: [email protected]
---
[5] And finally... Species variety is the spice of life (AOP)
DOI: 10.1038/nature11118
The effects of species loss on ecosystems are on par with many other global environmental changes, according to a report in Nature this week. Although loss of biodiversity is known to cause reductions in ecosystem function, how the sizes of these effects compare with the effects of environmental changes has been unclear. The latest findings highlight a major role for biodiversity loss in driving ecosystem changes.
David Hooper and colleagues analysed 192 published studies to assess the effects of changing biodiversity and several environmental factors on productivity and decomposition ― two processes important in all ecosystems. Intermediate species loss (21–40%) has effects comparable to those of climate warming on plant productivity. The effects of such losses on decomposition exceed those of elevated levels of atmospheric carbon dioxide (CO2) and nutrient pollution. The effects of higher levels of extinction (41–60%) rival those of warming, ozone, acidification, elevated CO2 and nutrient pollution.
The authors conclude that their results emphasize the importance of including the effects of biodiversity changes in future assessments of ecosystem function changes.
CONTACT
David Hooper (Western Washington University, Bellingham, WA, USA)
Tel: +1 360 650 3649; E-mail: [email protected]
---
Droplet transmission of an avian-human reassortant H5 influenza virus (AOP; N&V)
DOI: 10.1038/nature10831
Droplet transmission of an avian–human reassortant H5-haemagglutinin (HA)-containing influenza virus in an experimental setting is reported online in Nature this week. The work answers the question whether viruses containing HA from avian H5N1 virus can support mammalian transmission and move towards pandemic potential. It could form the basis for further experiments to increase our understanding of the basic biology of influenza virus transmission and for use in future surveillance programs to predict the emergence of virus isolates with pandemic potential.
Yoshihiro Kawaoka and colleagues generated a virus possessing a mutated HA gene from an avian H5N1 virus — which mediates virus binding to host cellular receptors — and the seven remaining gene segments from a human 2009 pandemic H1N1 virus. They show that four mutations in H5 HA are sufficient to allow transmission of the recombinant virus via respiratory droplets in a ferret model.
The authors note that it is not known whether these four mutations would be sufficient for transmission of wholly avian H5N1 viruses among mammals, including humans; the genetic origin of the remaining seven viral genes and further mutations within them may contribute to transmissibility in mammals. The work suggests that H5-HA-containing viruses with pandemic potential, including avian–human reassortant viruses, may emerge.
As humans lack immunity to H5 HA, these findings have implications for pandemic preparedness. Knowledge of the molecular changes that contribute to transmissibility in mammals could also help to make more specific vaccines against viruses possessing such an HA.
The paper will be freely available and is accompanied by an Editorial from Nature, a News and Views, and an independent risk assessment commissioned by the journal.
CONTACT
Yoshihiro Kawaoka (University of Wisconsin-Madison, WI, USA)
E-mail: [email protected]
Joseph Sriyal Malik Peiris (HKU-Pasteur Research Centre, Hong Kong) N&V Author
E-mail: [email protected]
ALSO IN THIS ISSUE:
[6] Liquid-crystal-mediated self-assembly at nanodroplet interfaces (pp 86-89)
[7] A unifying model for mTORC1-mediated regulation of mRNA translation (pp 109-113; N&V)
[8] Preferential electrical coupling regulates neocortical lineage-dependent microcircuit assembly
DOI: 10.1038/nature10958
[9] Clonally related visual cortical neurons show similar stimulus feature selectivity
DOI: 10.1038/nature11110
---
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.
AUSTRIA
Grambach: 3
CANADA
Montreal: 2
Montréal: 5
Vancouver: 2, 5
CHINA
Shanghai: 8
COLOMBIA
Sede Medellín: 6
GERMANY
Halle: 3
Magdeburg: 3
Munich: 3
JAPAN
Kanagawa: 4
Sayo: 4
Sendai: 4
Tokyo: 4
MÉXICO
México City: 6
SWEDEN
Asa: 2
Göteborg: 5
Lund: 2
SWITZERLAND
Lausanne: 2
UNITED KINGDOM
Belfast: 1
Edinburgh: 1
Plymouth: 2
UNITED STATES OF AMERICA
Arizona
Flagstaff: 5
Tucson: 1, 2
California
Berkeley: 9
Irvine: 3, 5
La Jolla: 2, 8
Pasadena: 1
Santa Barbara: 2, 5
Colorado
Boulder: 2
Denver: 2
Connecticut
Storrs: 2
Hawaii
Honolulu: 1
Maine
Orono: 2
Maryland
Baltimore: 1
College Park: 2
Massachusetts
Boston: 7
Cambridge: 1, 7
Michigan
Ann Arbor: 5
New Jersey
Princeton: 1
New York
New York: 2, 8, 9
Palisades: 2
Stony Brook: 9
North Dakota
Fargo: 2
Ohio
Columbus: 8
Pennsylvania
Doylestown: 6
Pittsburgh: 1
Texas
Austin: 2
Vermont
Burlington: 5
Virginia
Charlottesville: 3
Gloucester Point: 5
Washington
Bellingham: 5
Wisconsin
Madison: 6
Milwaukee: 2
---
PRESS CONTACTS:
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Eiji Matsuda, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature London
Tel: +44 20 7843 4502; E-mail: [email protected]
---
About Nature Publishing Group (NPG):
Nature Publishing Group (NPG) is a publisher of high impact scientific and medical information in print and online. NPG publishes journals, online databases and services across the life, physical, chemical and applied sciences and clinical medicine.
Focusing on the needs of scientists, Nature (founded in 1869) is the leading weekly, international scientific journal. In addition, for this audience, NPG publishes a range of Nature research journals and Nature Reviews journals, plus a range of prestigious academic journals including society-owned publications. Online, nature.com provides over 5 million visitors per month with access to NPG publications and online databases and services, including Nature News and NatureJobs plus access to Nature Network and Nature Education’s Scitable.com.
Scientific American is at the heart of NPG’s newly-formed consumer media division, meeting the needs of the general public. Founded in 1845, Scientific American is the oldest continuously published magazine in the US and the leading authoritative publication for science in the general media. Together with scientificamerican.com and 15 local language editions around the world it reaches over 3 million consumers and scientists. Other titles include Scientific American Mind and Spektrum der Wissenschaft in Germany.
Throughout all its businesses NPG is dedicated to serving the scientific and medical communities and the wider scientifically interested general public. Part of Macmillan Publishers Limited, NPG is a global company with principal offices in London, New York and Tokyo, and offices in cities worldwide including Boston, Buenos Aires, Delhi, Hong Kong, Madrid, Barcelona, Munich, Heidelberg, Basingstoke, Melbourne, Paris, San Francisco, Seoul and Washington DC. For more information, please go to www.nature.com.
---
PICTURES: While we are happy for images from Nature to be reproduced for the purposes of contemporaneous news reporting, you must also seek permission from the copyright holder (if named) or author of the research paper in question (if not).
HYPE: We take great care not to hype the papers mentioned on our press releases, but are sometimes accused of doing so. If you ever consider that a story has been hyped, please do not hesitate to contact us at [email protected], citing the specific example.
