Geochemistry: Silicon in the Earth’s core

Silicon may already have been present in the Earth’s core before the Moon formed.The finding could help explain the isotopic differences in silicon content that exist between various celestial bodies.
The iron isotopes found in basaltic rocks from the Earth and Moon have a relatively heavy atomic mass compared with those from Mars, Vesta and primitive meteorites. But the origin of this has been unclear because other elements do not seem to show the effect. Alex N. Halliday and colleagues now show that the silicon isotopic compositions of basaltic rocks from the Earth and Moon are also distinctly heavy.
That the Earth and Moon share similar isotopic compositions of bulk silicate is consistent with the idea that different isotopes of various elements were mixed up and then reached equilibrium when the young Earth collided with a Mars-sized body to form the Moon. And if so, the authors conclude that silicon was already a light element in the Earth’s core before the Moon formed.

CONTACT
Alex N. Halliday (Oxford University, UK)
Tel: +44 1865 272 969; E-mail: alexh@earth.ox.ac.uk

Tim Elliott (University of Bristol, UK) N&V author
Tel: +44 117 954 5426; E-mail: Tim.Elliott@bristol.ac.uk

Optics: Nanowire light source

A nanowire that functions as a light source has been developed, enabling researchers to probe nanoscale structures with high resolution. The new light source is compatible with a physiological environment and so is of interest for bio-imaging applications.
Peidong Yang and colleagues developed a source of visible light based on an inorganic nanowire made from potassium niobate, a material that has nonlinear optical properties and so can convert light from one frequency to another. They then used optical tweezers to hold the nanowire and scanned it over a sample to make images of a test structure with subwavelength resolution.
The experimental set-up requires no electrodes or conventional electronic wiring, which means that the probe can be placed close to living tissue with minimum damage to the sample. This makes it an attractive bio-imaging tool, but the technique may also find use in advanced information technology, cryptography and signal processing circuits

CONTACT
Peidong Yang (University of California, Berkeley, CA, USA)
Tel: +1 510 643 1545; E-mail: p_yang@berkeley.edu

Interstellar chemistry: Blowing in the wind

Oxygen-rich stars may contribute more of our Galaxy’s chemical make-up than was previously thought.Many of the chemicals that make up our Galaxy are spewed out from old, evolved stars, and until now carbon-rich stars were thought the most likely contributory source. With more oxygen than carbon, oxygen-rich stars were expected to lock away carbon in the form of stable carbon monoxide and so contribute little to our Galaxy's chemical richness.
Lucy M. Ziurys and colleagues now report a variety of unexpected chemical compounds in the oxygen-rich shell of the red supergiant star VY Canis Majoris. The results suggest that oxygen-rich stars may be as chemically diverse as their carbon counterparts, and so are also likely to contribute to the chemical diversity of our Galaxy.

CONTACT
Lucy M. Ziurys (University of Arizona, Tucson, AZ, USA)
Tel: +1 520 621 6525; E-mail: lziurys@as.arizona.edu

Sun Kwok (Hong Kong University, China) N&V author
Tel: +852 2859 2682; E-mail: sunkwok@hku.hk

Evolution: Good genes gender specific?
‘Good genes’ for males are not necessarily ‘good genes’ for females.
In a long-term study of red deer (Cervus elaphus), Katharina Foerster and colleagues show that males with relatively high fitness tend to father daughters with relatively low fitness. In addition, males that carry genes for high female fitness tend to be selected against.
The study, which suggests that the selective advantage of good genes can be gender-specific, backs up theoretical predictions and results from fruitfly experiments. It is thought that this may have profound effects on the selection and maintenance of genetic variation in natural populations.

CONTACT
Katharina Foerster (University of Edinburgh, UK)
The author is currently in Germany and can be contacted on:
Tel: +49 81 57 93 23 20; E-mail: foerster@orn.mpg.de

Stem cells: New type of stem cell derived

A new type of rodent embryonic stem (ES) cell has been derived that is more similar to human ES cells than current mouse alternatives. With human ES cells hard to come by, it's hoped that the new cells will prove a useful model that will boost our understanding of human stem cell biology.
Previously, it was thought that mouse ES cells could only be obtained from embryos before they had implanted into the uterus wall. Ronald D. G. McKay and colleagues and Ludovic Vallier and colleagues have now isolated rodent ES cells from embryos after they had implanted, from a tissue called the epiblast.
Unlike pre-implantation mouse ES cells, these new cells share many defining features with human ES cells. They grow like human ES cells, have similar patterns of gene expression and cell surface markers, and can produce many different cell types — as has already been shown for mouse ES cells.
Human ES cells are of interest from a basic biology and a therapeutic point of view, but researchers still need to understand fully the signals and processes that control their differentiation into specific cell types. The derivation of this new type of ES cell provides an experimental model to accelerate the use of human ES cells in science and medicine.
CONTACT
Ronald D. G. McKay (NINDS-NIH, Bethesda, MD, USA) Author paper [1]
Tel: +1 301 496 5284; E-mail: mckayr@ninds.nih.gov

Ludovic Vallier (University of Cambridge, UK) Author paper [2]

Laure Thomas (Senior Press Officer, MRC, London, UK)
Tel: +44 207 670 5139 or 07818 428 297 out-of-hours; E-mail: laure.thomas@headoffice.mrc.ac.uk

BioCarrier: A Novel Molecular Carrier from Newcastle disease virus

Researchers: Khatijah Yusoff, Tan Wen Siang, Kho Chiew Ling, Amir Rabu
Various kinds of carrier molecules have been used to deliver nucleic acids, drugs, vaccines and other important compounds. Researchers at Universiti Putra Malaysia have developed a molecular carrier for immunogenic peptides which can be used for the development of multicomponent vaccines, diagnostic reagents and the delivery of novel therapeutics or drugs (Malaysian Patent Pending: PI 20004837 and PI 20021709; US Patent Application No. 09/970,851).
They discovered that the nucleocapsid protein of a local Malaysian poultry virus (Newcastle disease virus) produced in Escherichia coli assembles into ring-like and herringbone-like particles. It is possible to manipulate the lengths of these particles by genetically engineering one end of this nucleocapsid protein. In addition, these particles are able to be fused with foreign polypeptides. Some of the advantages of this carrier molecule are its ability to increase the solubility of proteins, deliver immunogenic peptides or proteins in animals, as well as aid the purification of specific protein molecules.
Several fusion proteins have been constructed. These include the antigenic regions of the Newcastle disease virus, Nipah virus, hepatitis B virus, enterovirus virus 71, chicken anemia virus, and infectious bronchitis virus. Chickens inoculated with these particles mounted an immune response against the foreign peptides, supporting the use of these particles as carriers for immunogens in the development of multicomponent vaccines and immunological reagents.
contact:
Prof. Datin Paduka Dr. Khatijah Mohd Yusoff (contact details available to registered journalists only. Please click on link below)
or
Dr Nayan KANWAL Email: ndeeps@admin.upm.edu.my

Ecology: Managing Amazonian rainforest regrowth
Tropical forest regrowth depends on a delicate balance between nitrogen and phosphorus. The findings should help researchers predict how long it takes for tropical forests to recover after clearance, and should contribute to better management of disturbed Amazonian ecosystems.
Around 16% of the original Amazon Basin rainforest has been cleared for agriculture, but it's thought that up to half of this is now being allowed to regrow. Eric A. Davidson and colleagues now show that nitrogen and phosphorus levels influence this regrowth, with different factors proving limiting at different stages of maturation.
Early on after agricultural abandonment, nitrogen levels in the soil are low, so the plants conserve the little that they have. But as the forests mature and nitrogen levels in the soil rise, phosphorus becomes the limiting factor for plant regrowth. Trees become less conservative with nitrogen, nitrogen cycling recovers, and the ecosystem even leaks some nitrogen back to the atmosphere in the form of the greenhouse gas nitrous oxide.

CONTACTEric A. Davidson (Woods Hole Research Center, Falmouth, MA, USA)
Tel: +1 508 540 9900 x132; E-mail: edavidson@whrc.org

Chemistry: New method for making biofuels
Simple sugars can be turned into a new, potentially useful biofuel, thanks to an approach.Although some challenges remain for commercial applications, this process may help decrease our dependence on petroleum in the near future.
James A. Dumesic and co-workers have developed a catalytic process that converts the simple sugar fructose into 2,5-dimethylfuran. Compared with ethanol, the only renewable liquid fuel currently produced in large quantities, 2,5-dimethylfuran has an energy density 40% higher and is less volatile. It's also insoluble in water, making it easier to obtain in its pure form.
Fructose can be obtained directly from biomass or derived from glucose, another simple sugar. With diminishing fossil fuel reserves and ongoing concerns about global warming, hopes are high that renewable energy sources, such as biomass, will provide a significant contribution to the world's energy needs.

CONTACT
James A. Dumesic (University of Wisconsin, Madison, WI, USA)
Tel: +1 608 262 1095; E-mail: dumesic@engr.wisc.edu

Lanny D. Schmidt (University of Minnesota, Minneapolis, MN, USA) N&V author
Tel: +1 612 625 9391; E-mail: schmi001@umn.edu



Liquid mirror made for the Moon
Scientists have successfully coated an ionic liquid with silver, an achievement that may one day find use as a liquid mirror in a lunar telescope.
The surface of the liquid is smooth and the silver coating remains stable for months, Ermanno F. Borra and colleagues reports. The ionic liquid underneath the silver does not evaporate in a vacuum and remains liquid down to a temperature of around 175 kelvin.
These features mean the device may be well suited for use inside a Lunar Liquid Mirror Telescope, a concept that is under consideration. An optical telescope with an aperture of 20 to 100 metres located on the Moon would be able to observe objects 100 to 1,000 times fainter than the proposed next generation of space telescopes. And a Lunar Liquid Mirror Telescope may prove easier and cheaper to build than its conventional equivalent.

CONTACT
Ermanno F. Borra (Universite Laval, Quebec, Canada)
Tel: +1 418 656 7405; E-mail: borra@phy.ulaval.ca

Robin Rogers (The Universiy of Alabama, Tuscaloosa, AL, USA) N&V author
Tel: +1 205 348 4323; E-mail: RDRogers@Bama.ua.edu

Molecular Biology:Seeing histone tails specifically
An explanation of the mechanism by which certain factors involved in gene regulation act specifically. . The study, which could ultimately provide a basis for new drug targets, reports on how some histone modifications are recognized within the cell.
DNA in the cell is wrapped around histones to form chromatin, whose structure is regulated by a complex array of factors, which together alter the accessibility and activity of the underlying packaged genes. Each histone has multiple sites that can be covalently modified, and these modifications are associated with distinct genomic activities, including whether the underlying genes are switched on or off.
Understanding how the enzymes that modify histones recognize their specific site, and either modify or remove modifications is a key goal in deciphering gene regulation. Raymond Trievel and colleagues report structures of two key regulators of histone modifications in the JMJD2 family bound to their target substrate sites, indicating how these enzymes recognize and thus remove modifications at particular sites. This starts to reveal the mechanism of specificity for factors involved in regulation of genes such as androgen hormone responsive targets, and may provide a basis for drug discovery, targeting this and other family members in diseases such as cancer.

Author contact:Raymond Trievel (University of Michigan, Ann Arbor, MI, USA)
Tel: +1 734 677 0928; E-mail: rtrievel@umich.edu

MOLECULAR BIOLOGY:How cancer cells keep their telomeres

cancer cells stop their chromosome ends from becoming shorter.
In order to keep their fitness, all cells need to prevent their chromosome ends (telomeres) from reducing with each division. The shortening of telomeres might be implicated in the aging process. For cancer cells, which divide more frequently than normal cells, the maintenance of telomeres is even more critical. Some types of cancer cells do this by producing more of an enzyme called telomerase; others use an alternative pathway (called ALT), whereby their telomeres get recruited to specialized regions in the nucleus, called PML bodies.
Hongtao Yu and Patrick Ryan Potts determined that telomeres go to PML bodies when the proteins that cap the telomeres are tagged with a small protein called SUMO. They also identified the proteins that tag the telomeres. In their absence, the telomeres in ALT cancer cell lines get shorter, and the cells eventually lose their ability to grow.
This work reveals a mechanism used by several kinds of cancer cells to proliferate, and could also have relevance for the normal physiology of cells. However, since the proteins play an important role in normal cells, targeting them for cancer therapy may not be feasible.

Author contact:

Hongtao Yu (University of Texas Southwestern Medical Center, Dallas, TX, USA)
Tel: +1 214 645 6161; E-mail: hongtao.yu@utsouthwestern.edu

Bio-technology:Tastier GM tomatoes?
More people prefer the flavour of a new type of GM tomato to that of unmodified tomatoes.
Efraim Lewinsohn and colleagues expressed a variant of a lemon basil gene in ripening tomatoes. The genetically modified fruits generated sufficiently different levels of rose- and lemon-scented aromas that 78 out of 82 people could distinguish them from conventional tomatoes. The change in smell achieved in the GM tomato, which is more impressive than previous efforts to modify plant taste and aroma, results from production of fragrances not produced by conventional tomatoes and may be influenced by altered levels of volatile compounds normally generated by tomatoes.The GM tomatoes were rated tastier by 49 of the 82 people surveyed; 29 preferred unmodified tomatoes and 4 did not express any preference.
One potential drawback is the GM tomatoes contain around half as much lycopene as traditional tomatoes, so didn’t look as red. Lycopene is a beneficial antioxidant that has been proposed to counteract heart disease and cancer. Although some evaluators considered the GM tomato samples to be sweeter, sugar levels were not affected by the genetic modification.
The same approach might enable modification of the aromas of a range of fruits and flowers.
Author contact:
Efraim Lewinsohn (Newe Yaar Research Center, Ramat Yishay, Israel)
Tel: +972 4 953 9552; E-mail: twefraim@agri.gov.il

Omega 3 fatty acids may prevent eye disease

Increasing the dietary intake of omega-3-polyunsaturated fatty acids may prevent eye disease.
Many sight-threatening diseases such as retinopathy of prematurity (a disease which affects prematurely born babies) and diabetic retinopathy feature abnormal growth of blood vessels in the eye. Lois Smith and colleagues studied the influence of omega-3-polyunsaturated fatty acids on vessel loss and regrowth after injury in the mouse retina. They found that increasing the acids by dietary or genetic means limited pathological blood vessel growth by reducing the production of inflammatory mediators in the eye.
Western diets are often deficient in omega-3-polyunsaturated fatty acids, and premature infants lack this molecule, which is transferred from mother to fetus during the third trimester of pregnancy. So, supplementing omega-3-polyunsaturated fatty acid intake may help prevent retinopathy.

Author contact:
Lois Smith (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 919 2529; E-mail: lois.smith@childrens.harvard.edu

Stellar weather

Stars might also experience weather, report Oleg Kochukhov and co-workers.Their study challenges current models of structure formation within stellar atmospheres.
By tracking mercury clouds on alpha Andromedae over a seven-year period, the researchers discovered cloud dynamics similar to the weather patterns that exist on Earth and the giant gas planets. Other stars also host chemical and temperature spots, but astronomers generally believe that a star’s magnetic field is responsible for its surface structure — this explanation applies to sunspots on the Sun, for instance. But alpha Andromedae is non-magnetic, hence its cloud formation and evolution cannot be magnetic-field driven. Rather, the researchers’ analysis suggests that the same dynamical and self-organization processes that govern our weather are also responsible for those mercury clouds.
The abundance of heavy elements, such as mercury, in the atmosphere is used as a measure of a star’s evolution, but the diversity of the observed heavy-element concentration between stars of similar mass and age has puzzled astronomers. This study could help explain that variation.
Author contact:
Oleg Kochukhov (Uppsala University, Sweden)
Tel: +46 18 471 5993; E-mail: Oleg.Kochukhov@astro.uu.se

Molecular biology: Cancer drug has unexpected mode of action

A particular type of cancer drug works in a previously unexpected way.Topoisomerase inhibitors, such as topotecan, are a class of anti-cancer drugs that act on proteins that relax a form of built-up stress in DNA called supercoiling. It's thought that they act by stabilizing a covalent complex between the topoisomerase enzyme and DNA, which then sets up a road-block to the DNA replication machinery triggering cell death.
Daniel A. Koster and colleagues look at single topoisomerase molecules ‘in the act’. They find that the inhibitors don't just stabilize an intermediate but actually affect the ability of topoisomerase to relax DNA supercoiling, suggesting a new mechanism by which these drugs cause cytotoxicity.

Author contact:Daniel A. Koster (Delft University of Technology, Netherlands)
Tel: +31 152 781 025; E-mail: d.a.koster@tudelft.nl

Molecular biology: RNA from blood to brain

It’s now possible to perform gene therapy on the brain via intravenous injection, in mice at least. The finding opens a new potential line of noninvasive treatment for neuronal disease.
Getting any drug into the brain can be a problem because the blood–brain barrier acts as a barricade keeping systemic treatments out. Manjunath N. Swamy and colleagues show that when small fragments of RNA attached to a piece of viral protein are injected into the bloodstream of mice infected with a fatal form of encephalitis, the RNA–protein complex travels to the brain. The protein part binds neuronal cells, delivering the RNA part, which becomes internalised and can silence key genes through a process called RNA interference. The result — about 80% of treated animals survived, whilst all of the non-treated animals died.
Although the method needs tweaking to improve efficiency, the technique may offer a useful way of delivering nucleic acids and small-molecule drugs into the brain.
Author contact:
Manjunath N. Swamy (CBR Institute for Biomedical Research, Boston, MA, USA)
Tel: +1 617 278 3240; E-mail: swamy@cbrinstitute.org

Neurophysiology: 'Rejuvenating' neurons to protect against Parkinson's disease

Encouraging neurons to revert to a more juvenile state might help slow or stop the progression of Parkinson's disease. Using mouse models of Parkinson’s disease, James Surmeier and colleagues report that blocking calcium channels with a commonly used drug 'rejuvenates' the dopamine-containing neurons that are typically affected by the disorder.
Parkinson's disease is a neurodegenerative disorder characterized by the death of dopamine-containing neurons in a region of the brain called the substantia nigra — but why these neurons are particularly vulnerable remains unclear. This research shows that these neurons rely on calcium channels to maintain their rhythmic activity. This reliance increases with age and leads to sustained elevations in cytosolic Ca2+, which could ultimately be detrimental to the cells. By blocking calcium channels in adult neurons — in both in vitro and in vivo mouse models — the authors were able to induce a more juvenile form of neural activity, forcing the neurons to use other ion channels and protecting them against disease progression.
The authors, speculate that these findings point to a potential therapeutic strategy that might protect against Parkinson's disease in humans, and possibly also broaden the therapeutic window for patients in the early stages of the disease.
Author contact:
James Surmeier (Northwestern University, Chicago, IL, USA)
Tel: +1 312 503 4904; E-mail: j-Surmeier@northwestern.edu

Planetary science: Water on Mars revisited


There may once have been an ocean of water on the surface of Mars after all. A change in the planet’s orientation could explain some features controversially interpreted as ancient martian shorelines.
Some think that the northern plains of Mars, covering nearly one-third of the planet’s surface, may have contained an ocean in the distant past. The most provocative piece of evidence for this is a set of surface features that ring the plains for thousands of kilometres, which have been interpreted as a series of former shorelines. But these ‘shorelines’ vary in elevation by up to several kilometres, instead of all being at ‘sea level’, casting doubt on this theory.
J. Taylor Perron and colleagues now show that true polar wander — a change in the orientation of the surface of a planet with respect to its rotation pole — could explain the elevations of the proposed shorelines, reviving the hypothesis that an ancient ocean once covered a large part of the martian surface.
CONTACTJ. Taylor Perron (Harvard University, Cambridge, MA, USA)
Tel: +1 617 495 4687; E-mail: perron@eps.harvard.edu

Maria T. Zuber (Massachusetts Institute of Technology, Cambridge, MA, USA) N&V author
Tel: +1 617 253 6397; E-mail: zuber@mit.edu

Ecology: Human carbon footprint leaves a lasting mark on forests

Human activities are having profound and overwhelming effects on the carbon balance of forests in the Northern Hemisphere. The finding has implications for forest management as well as our understanding of the global carbon and nitrogen cycles.
Human activities, such as agricultural fertilization and biomass burning, are pumping more nitrogen into the atmosphere, which in turn is having a positive effect on the growth of Northern Hemisphere forests, report Federico Magnani and colleagues. As the forests grow they lock away more carbon, so human activities are directly changing the dynamics of the carbon cycle, albeit in a complex and non-linear way.
The team’s study takes into account the many variables affecting carbon cycling, including rising temperatures and carbon dioxide levels, changes in land use, and plant photosynthesis and respiration. And the results show that mankind is ultimately controlling the carbon balance of temperate and boreal forests, either directly through forest management or indirectly through nitrogen deposition.
CONTACT
Federico Magnani (Universita di Bologna, Italy)
Tel: +39 051 209 6466; E-mail: federico.magnani@unibo.it

Peter Hogberg (Swedish University of Agricultural Sciences, Umea, Sweden) N&V author
Tel: +46 90 78 68 353; E-mail: Peter.Hogberg@sek.slu.se

Physiology: Why cold is such a pain
Katharina Zimmermann and colleagues show that a protein called Nav1.8 allows information to be transmitted along sensory nerve fibres in cold conditions. The molecule is a voltage-gated sodium channel, an integral membrane protein that allows sodium ions to pass through a neuron's outer membrane.
There are other voltage-gated sodium channels in sensory neurons, but this one keeps working when the temperature drops — in fact, its currents are actually larger in colder conditions. This may help explain why, although sensory acuity deteriorates at cold temperatures, pain perception persists and cold stimuli themselves can be painful.
CONTACTKatharina Zimmermann (University Erlangen-Nuremberg, Erlangen, Germany)
Tel: +49 91 31 85 22 228; E-mail: zimmermann@physiologie1.uni-erlangen.de

Transients in the sky: Stellar puzzle
In 2004, astronomers observed an incredibly bright stellar flare. Then two years later, they spotted a type 1b supernova in the same vicinity. Researchers now confirm that the two events occurred in the same place, making it an unlikely coincidence and something of a puzzle.
Andrea Pastorello and colleagues offer a few explanations. The initial flare could have come from a Wolf–Rayet star — a very hot, massive, dying star that throws out a lot of gas. Or it could have come from a binary system, containing the supernova and a luminous blue variable — a bright, hypergiant, variable star that flares periodically. The authors’ conclusions support another publication by an independent group in the journal Astrophysics (R. J. Foley et al. Astrophys. J. 657, L105–L108; 2007).
CONTACT
Andrea Pastorello (Queen's University Belfast, UK)
Tel: +44 28 9097 3509; E-mail: a.pastorello@qub.ac.uk

Planetary science: Saturn’s magnetosphere gets the Cassini treatment

Saturn’s magnetosphere overturns in a way similar to that of Jupiter.
It’s known that cold, dense plasma from Jupiter’s inner magnetosphere is flung outward and replaced by hotter plasma from the outer magnetosphere — a little like convection in a pot of liquid. But whether the same is true for Saturn’s magnetosphere has been a matter of debate, given that Saturn’s magnetosphere shares other features with that of Earth. William Lewis and colleagues now study the cold plasma next to hot, inward-moving plasma in its magnetosphere to show that this cold plasma is outward bound, so Saturn’s magnetosphere does indeed have similar overturning to Jupiter’s — a discovery made possible by Cassini’s plasma spectrometer.
CONTACTWilliam Lewis (Southwest Research Institute, San Antonio, TX, USA)
Tel: +1 210 522 5651; E-mail: wlewis@swri.edu

Genetics: DNA ‘instruction manual’ deciphered

After sequencing the human genome, the next logical step is to figure out how cells make use of this instruction manual. With the results of a huge project that identifies and analyses functional elements taken from part of the human genome.
Thirty-five groups provided over 200 data sets, comprising around 1% of the human genome, for the pilot of the Encyclopedia of DNA Elements (ENCODE) Project. Ewan Birney and an international consortium then described which parts of the selected DNA are transcribed into RNA, where specific proteins are bound to the DNA, how the sequence compares to that of other organisms, and what form the structure of chromatin (the complex of DNA and proteins that make up chromosomes) takes in the selected regions.
From this, the consortium derived a number of exciting new insights into both the nature and evolution of DNA sequences important for biological function. For example, most of the DNA studied appears to be transcribed into RNA, and these DNA transcripts overlap extensively. This is at odds with the view that the human genome contains a relatively small set of discrete genes alongside a mass of biologically inactive 'junk DNA'.
The team also found that around one-half of the genome's functional elements appears to be able to change sequence more freely than expected across mammalian evolution. This suggests the existence of a large pool of neutral elements that are biochemically active but provide no specific benefit to the organism, which may serve as a 'warehouse' for natural selection.
CONTACT
Ewan Birney (EMBL-European Bioinformatics Institute, Cambridge, UK)
Tel: +44 1223 494 420; E-mail: birney@ebi.ac.uk

Anna-Lynn Wegener (EMBL Press Officer, Heidelberg, Germany)
Tel: +49 6221 387 452; E-mail: wegener@embl.de

Zhiping Wang (Boston University, MA, USA) Co-author
Tel: +1 617 353 3509; E-mail: zhiping@bu.edu

John M. Greally (Albert Einstein College of Medicine, Bronx, NY, USA) N&V author
Tel: +1 718 430 2875; E-mail: jgreally@aecom.yu.edu

Evolution: A gigantic bird-like dinosaur

The remains of a gigantic, surprisingly bird-like dinosaur have been uncovered in Inner Mongolia, China. The animal — which lived in the Late Cretaceous (about 70 million years ago) — is thought to have had a body mass of about 1,400 kilograms, which is surprising as most theories suggest that carnivorous dinosaurs got smaller as they got more bird-like. The dinosaur has been classed as a new species and genus.
Xing Xu and colleagues carried out a phylogenetic analysis of the skeleton and have grouped the fossil with a family that included the beaked, bird-like Oviraptor because of its similarly avian features. What is most striking, however, is that at 1,400 kilograms the fossil is about 35-times heavier than other similar feathered dinosaurs, which rarely exceeded a body mass of 40 kilograms.
The authors estimate that the new dinosaur would have been about eight metres long and would have stood, at the shoulder, twice the height of a man. They suggest that a growth rate considerably faster than large North American tyrannosaurs contributed to this. The team also noticed lines of arrested growth on the fossil, indicating that it was still a young adult when it died, so the full-sized dinosaur may have been even larger than this. But, despite its great size, many features of its anatomy were more bird-like, rather than less, as would have been expected.
CONTACT
Xing Xu (Chinese Academy of Sciences, Beijing, China)
Tel: +86 10 8836 9196; E-mail: xu.xing@ivpp.ac.cn or xingxu@vip.sina.com

Physical Activity May Reduce Risk of Gestational Diabetes Mellitus
SEATTLE - Gestational diabetes mellitus (GDM) complicates 4 percent to 7 percent of all pregnancies in the United States and poses a risk to both infant and mother. However, results of a new study conducted by researchers from Swedish Medical Center's Perinatal Studies program suggests physical activity may reduce risk of GDM.
Babies born to mothers with GDM may be large at birth and suffer complications such as jaundice. These children are more likely to become obese and develop diabetes in early adulthood. Women with GDM are at increased risk of developing other complications during pregnancy, such as preeclampsia, and they are more likely to develop type 2 diabetes after pregnancy.
The results of this new study suggest that women who are physically active during the year before and/or during early pregnancy may be less likely to develop GDM.
The study, which was funded by The National Institute of Child Health and Human Development at National Institutes of Health, suggests that current efforts to encourage Americans to engage in more frequent physical activity may also benefit pregnant women and result in substantial reductions in the incidence of GDM.
Lead author Jennifer Dempsey and colleagues report that women who participated in recreational physical activity during the year before pregnancy reduced their risk of GDM by 56 percent. During this time period, women who exercised for about four hours per week were 76 percent less likely to develop GDM when compared with women who did not exercise. In addition, women who participated in recreational physical activity both before and during early pregnancy enjoyed a 69 percent reduction in risk.
The study, which is ongoing at Swedish Medical Center in Seattle and led by Drs. Michelle Williams, Tanya Sorensen and David Luthy, was presented at the 24th annual meeting of the Society for Maternal-Fetal Medicine in New Orleans.
The investigators are currently conducting additional analyses to determine which metabolic or physiological changes associated with exercise may contribute to this reduced risk of GDM. They are also conducting studies to help identify which specific types, intensities and duration of exercise are associated with optimal pregnancy outcomes.