It’s all in the Electron Spin
Japanese researchers show subtle fluctuations in electron spins are the origin of magnetism and superconductivity in a common oxide
Magnetism and superconductivity are material properties that generally exclude each other. The reason is that in a magnet, the electron spins—tiny magnets responsible for the material’s magnetism—align in a common direction. On the other hand, superconductivity requires the pairing of electrons with opposing spins.
In that respect, sodium cobalt oxide, NaxCoO2, is unusual. It has a lattice structure with crystal planes formed by cobalt (Co) and oxygen (O) atoms. Along those planes it is ferromagnetic. However, when brought into contact with water, water molecules integrate into the material’s crystal structure forming a slightly modified hydrated compound, NaxCoO2 • yH2O. And, this compound shows superconductivity along the CoO2 planes at low temperatures.
However, a team of researchers from RIKEN’s Discovery Research Institute in Wako, and colleagues from the universities of Chofu and Nagoya, now propose that magnetism and superconductivity in the non-hydrated and hydrated forms of NaxCoO2 actually share a common origin (1).
Typically, the origin of properties such as magnetism or superconductivity lies in the way electrons occupy the internal electronic states of a material. Like water filling an empty bucket, electrons in a material occupy all available electronic states beginning with the ones having the lowest electronic energy. Those electrons ending up at the ‘top’ of the bucket, also called the ‘Fermi surface’ (Fig. 1 - click on link below), are responsible for the electronic behavior of a material.
This Fermi surface can take quite complicated shapes. It can even consist of completely separate regions, particularly in crystals that are not symmetric in all directions. This is the case for NaxCoO2.
The researchers studied the theoretical electron interaction between the disconnected parts of the Fermi surface and found that electrons can jump between these ‘islands’. This is made possible by so-called ‘spin fluctuations’—tiny changes in the way electron spins are aligned with each other. Through these synchronized tilts in their spins, electrons can gather just the right amount of energy to bridge the gaps at the Fermi surface. This electron interaction is crucial to mediate the material’s electronic properties and, according to Ryotaro Arita from the RIKEN team, “provides the necessary incentive for the electrons to create either ferromagnetism or superconductivity”.
Such a common origin for both phenomena in NaxCoO2 is quite rare, although Arita is convinced that if proven experimentally, this might lead to the discovery of other superconducting materials with disconnected Fermi surfaces.
Reference
1. Kuroki, K., Ohkubo, S., Nojima, T., Arita, R., Onari, S. & Tanaka, Y. Unified origin for the 3D magnetism and superconductivity in NaxCoO2. Physical Review Letters 98, 136401 (2007).
For more information, contact
Saeko Okada
Email: okadas@riken.jp

Adult Stem Cells Show Promise for Peripheral Vascular Disease
Adult stem cells cultivated from patients' own blood can potentially improve the quality of life for patients whose lower extremities are affected by peripheral vascular disease, according to a study in China.
SHENZHEN, China, July 3, 2007 (medianowonline)-Beike Biotechnology Co., Ltd. today announced that a team led by Dr. Yang Xiaofeng at its collaborating hospital in Shenyang completed a study to assess clinical efficacy, safety, and feasibility of transplantation of peripheral blood stem cells for patients with peripheral vascular disease of the lower extremities.
Beike is best known for its research and treatments for ataxia, cerebral palsy, spinal cord injury and MS which are often covered by China Stem Cell News.However, Beike also has broad experience in research and treating vascular diseases with adult stem cells mostly through its collaboration with Shenyang 463 hospital.
A total of 152 patients with peripheral vascular disease of the lower extremities were enrolled into this non-controlled study from November 2003 to March 2006. The results were published in the Journal of Geriatric Cardiology which publishes original peer-reviewed clinical and experimental reports on all aspects of cardiovascular disease in the elderly.
A second study was completed during the same period comparing the relative improvement of lower limb ischemia (lack of blood supply) between transplantation of autologous peripheral blood stem cells and transplantation of bone marrow stem cells. The study is awaiting publication in a peer-reviewed journal.
At 12 weeks, primary symptoms, including lower limb pain and coldness, were significantly improved in 137 (90.1%) of the patients; limb ulcers improved or healed in 46 (86.8%) of the 53 patients, while 25 of the 48 (47.9%) patients with limb gangrene remained steady or improved. Angiography (an X-ray) before treatment, and at 12 weeks after treatment, was performed in 10 of the patients and showed formation of new collateral vessels.
The patients had no severe adverse effects or complications related to cell transplantation.
"These preliminary results, while encouraging, must be further researched in future controlled studies and reinforced by separate studies by other laboratories," said Yang Xiao Feng, Director of the Stem Cell Program for Vascular Diseases at Shenyang 463 Hospital.
The study followed previous studies done in the laboratory and pre-clinical work done in rabbits.
"There is evidence demonstrating significant improvement in the quality of life of patients receiving the treatment, including formation of new collateral vessels," said Sean Hu, Chairman of Beike Biotechnology group. "We are now working to collaborate with institutions in the U.S. to further substantiate this and other studies including those we are doing for neurological diseases using umbilical cord stem cells."
In 2006, Beike Biotechnology completed two studies involving eight patients with ALS. Two papers were published in the Journal of Zhenghou University of Medical Science. The first observed the effect of transplantation of umbilical cord blood mesenchymal stem cells (UCB-MSCs) on glutamate (Glu) levels in plasma and CSF of amyotrophic lateral sclerosis patients and the second observed the effect of umbilical cord blood mesenchymal stem cell transplantation on nervous system function of ALS patients.
The abstract of this study on treatment of peripheral vascular disease can be found at: http://www.jgeriatriccard.com/id10abstract-september06.html.

Fight against Cancer
UPM scientists are researching the possibility of using "tapai ubi", or fermented tapioca, as a prevention against cancer. Preliminary tests indicated that seven types of cancer, including cervical, ovarian, breast and leukaemia, could be prevented by eating tapai ubi.

Researchers: Latifah Saiful Yazan, Foo Hooi Ling, Raha Abdul Rahim and Loh Teck Chwen
UPM scientists are researching the possibility of using tapai ubi, or fermented tapioca, as a prevention against cancer. Lactobacillus plantarum UL4 (Lactic Acid Bacteria) isolated from local tapai ubi (fermented tapioca, Manihot esculanta ) is able to produce bacteriocin (designated as bacteriocin UL4) that shows broad inhibitory activities towards a numbers of pathogens, such as Bacillus cereus, Escherichia coli, Streptococcus pneumoniae, Staphylococcus aureus, Salmonella typhimurium, Enterococcus faecium and Listeria monocytogenes. Bacteriocin UL4 not only can withstand high temperatures up to 121ºC for 15 minutes but is also stable at temperatures below 15ºC for up to 60 days.
As for pH tolerence, the bacteriocin UL4 is also tolerable to broad pH range, which includes acidic (pH 2-5) and basic (pH 7-8) pH. The physiological effects of bacteriocin UL4 have been studied by feeding to post weaning rats as feed additive.
The feeding trial results demonstrated that it could reduce the total plasma cholesterol concentration and the Enterobacteriaceae counts significantly as compared to the control group. Under the study conducted at UPM, the bacterioicn UL4 also exhibited positive in vitro cytotoxic activities towards a few cancerous cell lines, for instances breast carcinoma (estrogen receptor-positive MCF7 and estrogen receptor-negative MDA MB231), cervical adenocarcinoma (HeLa), ovarian cancer (CaOV3) and acute promyelocytic leukaemia (HL60) cells.
However no detailed study has been carried out yet to evaluate the cancer chemopreventive activities of bacteriocin. By knowing the potential of the bacteriocin to fight various malignancies, this work is proposed to assess its anti-tumour promoting activity on mice induced with skin cancer. Our preliminary tests indicated that seven types of cancer, including cervical, ovarian, breast and leukaemia, could be prevented by eating tapai ubi.

Fishy genome swims into view
The medaka fish (Oryzias latipes), a popular pet in Japan and model organism in the laboratory, has had its genome sequenced.
Shinichi Morishita and colleagues estimate that the small egg-laying freshwater fish’s genome contains approximately 20,000 genes, of which around 2,900 appear new and unique to medaka.
Teleosts (fish with bony skeletons), such as the medaka fish, make up more than half of all vertebrate species and have adapted to life in a variety of marine and freshwater habitats. The evolution and diversification of their genomes is therefore crucial to understanding how vertebrates evolved.
The team compared their high-quality draft sequence against human, pufferfish (Tetraodon) and zebrafish genomes. It’s already known that at some point in the past the whole teleost genome doubled. The new study shows that the last common ancestor of medaka, pufferfish and zebrafish experienced 8 major rearrangements between chromosomes within just 50 million years of this event. But where the zebrafish genome has changed considerably since it diverged from the last common ancestor some 320 million years ago, the medaka genome has remained remarkably unchanged for over 300 million years.

CONTACT
Shinichi Morishita (University of Tokyo, Chiba, Japan)
Tel: +81 47 136 3984; E-mail: moris@cb.k.u-tokyo.ac.jp

Hurricanes: Back to normal?
The increase in the number of major Atlantic hurricanes since 1995 could be a recovery to normal activity, rather than a rise to unusually high levels. According to the study, which uses proxy records of vertical wind shear and sea surface temperature to reconstruct the number of major Atlantic hurricanes over the past 270 years, the storm frequency was anomalously low during the 1970s and 1980s.
The frequency of major hurricanes over the Atlantic Ocean has risen significantly since 1995, but it remains unclear whether this change is due to global warming or natural variability. One way to address this question is to consider changes in hurricane activity in the past, but reliable observations only cover the past few decades.
Johan Nyberg and colleagues used proxy records from corals and a marine sediment core that reflect changes in the two main parameters that influence hurricane activity — vertical wind shear and sea surface temperature — to reconstruct the frequency of major hurricanes over the Atlantic since 1730. The records show that the lull in hurricane activity from the late 1960s to early 1990s is an exception, and that the current active period from 1995 onwards reflects a return to ‘normal’ activity, rather than a direct response to increasing sea surface temperature. The records indicate that variations in vertical wind shear may have been responsible for the changes in hurricane frequency, although the underlying causes of changes in this parameter remain uncertain. The authors suggest that it is therefore crucial to understand future changes in the magnitude of vertical wind shear, because they may have a significant influence on hurricane activity.

CONTACT
Johan Nyberg (Geological Survey of Sweden, Uppsala, Sweden)
Tel: +46 18 17 91 94; E-mail: johan.nyberg@sgu.se

James B. Elsner (Florida State University, Tallahassee, FL, USA) N&V author
Tel: +1 850 877 4039; E-mail: jelsner@fsu.edu

Oncology: MicroRNAs and tumour suppression

The tumour suppressor p53 acts directly on a family of small RNAs that are vital for cell growth and replication. Already well known for its indirect effects, p53 is now shown to target the miR-34 family of microRNAs (miRNAs), which itself suppresses cell proliferation.
A global decrease in miRNA levels is often observed in human cancers, indicating that small RNAs may have a part to play in tumour suppression. However, little is known about how miRNA expression is regulated. Gregory J. Hannon and colleagues compared the miRNA expression profiles of wild-type and p53-deficient mouse cells. They identified a family of non-coding miRNAs — miR-34 — that is the direct target of, and thus regulated by, p53, and show that the ectopic expression of these miRNAs leads to growth arrest and, in some cases, cell senescence. This suggests that the miR-34 family acts as components of p53-mediated growth and arrest pathways, and the authors describe several miR-34 target genes that have roles in cell cycle progression.
miR-34 is one of only 18 mammalian miRNA families that are also present in Drosophila and the nematode worm Caenorhabditis elegans. This raises the possibility that the link between p53 and miR-34 might have arisen early in the evolution of the p53 network and may be important in p53 function in diverse species, the authors speculate. The paper represents one of the first discoveries of direct transcriptional regulators for miRNAs and is likely to be the tip of the iceberg.

CONTACT
Gregory J. Hannon (Cold Spring Harbor Laboratory, NY, USA)
Tel: +1 516 367 8889; E-mail: hannon@cshl.org

Stem cells: DNA damage contributes to stem cell ageing
DNA damage can cause premature ageing in bone-marrow-derived stem cells, making it harder for them to function. The finding has implications for the use of adult stem cells in transplantation.
Long-lived multicellular organisms depend on small pools of slowly dividing stem cells to replenish lost tissue, and it's important that these reserves are self-renewed and maintained with minimal mutations throughout life.
Derrick J. Rossi and colleagues now show that blood-forming stem cells from the bone marrow of mice accumulate DNA damage with age. This, they say, might underlie the reduced capacity of stem cells to yield new tissues and repair injury over time.
Richard J. Cornall and colleagues studied bone-marrow-derived stem cells from a mouse strain that has problems repairing DNA damage, and arrived at a similar conclusion — under physiological conditions, unrepaired DNA damage in stem cells can lead to an age-dependent decline in their numbers.

CONTACT
Derrick J. Rossi (Stanford University, CA, USA) Author paper [5]
Tel: +1 650 723 7389; E-mail: drossi@stanford.edu

Richard J. Cornall (Oxford University, UK) Author paper [6]
Tel: +44 1865 287 790; E-mail: richard.cornall@ndm.ox.ac.uk

Metabolic disease: Potential drug for atherosclerosis and type 2 diseases

A small-molecule inhibitor that has been successfully tested in mice may prove useful against chronic metabolic diseases such as atherosclerosis, obesity and type 2 diabetes.
Gökhan S. Hotamisligil and colleagues treated genetic mice models of various metabolic diseases with a drug that inhibits a protein called aP2. When given orally, the drug molecule reduced the size of atherosclerotic lesions in blood vessels. It also decreased blood glucose levels and increased insulin sensitivity in a model of obesity and insulin resistance.
aP2 is expressed in fat cells and scavenging white blood cells called macrophages, where it mediates metabolic and inflammatory reactions. It's already known that mice genetically manipulated to lack the protein are protected against various aspects of metabolic disease, suggesting that aP2 may prove a useful drug target for these conditions. This study backs this idea up, hinting that aP2 inhibitors may aid the treatment of human cardiovascular disease and diabetes.

CONTACT
Gökhan S. Hotamisligil (Harvard School of Public Health, Boston, MA, USA)
Tel: +1 617 432 1950; E-mail: ghotamis@hsph.harvard.edu

Genomics: Insights into seven diseases revealed

The true potential of the human genome is uncovered. The study compares 2,000 cases each of seven common diseases with 3,000 shared control patients, and unveils new genetic associations with these disorders. A pair of related papers in Nature Genetics offer further insights into two of the seven diseases investigated.
In the Nature article, researchers from the Wellcome Trust Case Control Consortium report genetic variants associated with the development of bipolar disorder, Crohn’s disease, coronary heart disease, type 1 and type 2 diabetes, rheumatoid arthritis and hypertension. In the first study from this large scope, the scientists found one genetic region newly associated with bipolar disorder, and another with coronary artery disease. A separate group of three markers are associated with rheumatoid arthritis. The authors also identify nine new genetic associations for Crohn’s disease and ten chromosome regions that contain genes related to diabetes.
Separate papers in Nature Genetics support the new insights into the chromosome regions involved in Crohn’s disease—reporting strong association for six new loci—and detail replication of some of the results for type 1 diabetes.
Peter Donnelly, Miles Parkes, John Todd and colleagues believe their findings offer avenues of research for each of the seven disorders. This work represents a major step towards dissecting the biological bases of common diseases; future work is already focusing on translating the findings into improvements in human health.

CONTACT
Peter Donnelly (Chair, Wellcome Trust Case Control Consortium, University of Oxford, UK)
Author paper [1]
Tel: +44 1865 285 385; E-mail: donnelly@stats.ox.ac.uk


Craig Brierley (Media Officer, Wellcome Trust, London, UK)
Tel: +44 20 7611 7329; E-mail: c.brierley@wellcome.ac.uk

Anne M. Bowcock (Washington University School of Medicine, St Louis, MO, USA) N&V author
Tel: +1 314 747 3264; E-mail: bowcock@genetics.wustl.edu

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.

Biology : Skin barrier formation and caspase-14



A protein known as caspase-14 has been identified as the enzyme involved in the protection of the skin against UVB damage and water loss, according to a study.
The involvement of caspase-family members in programmed cell death and inflammation is well understood but, a function for caspase-14 had previously not been identified. Using caspase-14 knockout mice, Wim Declercq and colleagues show that caspase-14 is responsible for the initial processing of profillagrin to fillagrin. Fillagrin is responsible for aggregating keratin and other proteins in the upper layers of the epidermis to form the stratum corneum – a layer of flattened dead-cell remnants that creates a protective barrier for the skin. The controlled processing of profillagrin to produce fillagrin ultimately maintains the integrity of the epidermis. In mice lacking caspase-14, their skin exhibits a defective stratum corneum and is more sensitive to water loss and UVB photodamage.
The identification of caspase-14 and its role in skin-barrier formation opens avenues for the pharmaceutical manipulation of this process to prevent the damage induced by UVB, the primary agent responsible for sunburn and skin ageing.
Author contact:
Wim Declercq (Ghent University, Belgium)
Tel: +32 9 33 13 660; E-mail: wim.declercq@dmbr.ugent.be


...And Control of all fates
Cell Biology investigates how pluripotency, the ability of a stem cell to differentiate into every cell type of the adult organism, is regulated.
Understanding how stem cells maintain their pluripotent state has involved the characterisation of a multitude of transcription factors – the proteins that determine whether a specific gene is expressed or not. Pluripotency in embryonic stem cells was thought to be controlled primarily by the transcription factors Oct3/4 and Sox2, as these proteins were believed to activate Oct-Sox enhancers – regulatory regions that determine the expression of pluripotent stem cell-specific genes. Shinji Masui and colleagues used mutant mice lacking the Sox2 gene to show that although Sox2 is needed for stem cell pluripotency, it is not required for the enhancers to function and in fact governs the expression of Oct3/4. The authors went on to show that this regulation is indirect, as Sox2 controls the expression of a number of transcription factors that in turn regulate Oct3/4 expression.
This study illustrates the precise regulation of pluripotency by key proteins, and reorders the hierarchy of these factors with Sox2 as the master regulator — another small step towards a complete understanding of stem cell biology.
Author contact:
Shinji Masui (International Medical Centre of Japan, Tokyo, Japan)
Tel: +81 3 3202 7181; E-mail: masui@ri.imcj.go.jp

The dual role of BRCA2 in DNA repair
The dual role of the gene BRCA2 in DNA repair is described in two independent studies. The studies from Stephen West’s and Luca Pellegrini’s groups shed light on the role of the gene, mutations of which result in predisposition to breast cancer and other malignancies.
The protein encoded by BRCA2 is involved in homologous recombination, a process whereby damaged DNA is repaired using an intact copy of DNA as a template. This process also includes the protein RAD51, which interacts directly with two different regions of BRCA2, called BRC and TR2. The BRC region had been previously suggested to be involved in terminating homologous recombination. Data from the two present studies indicate that the TR2 region can oppose the activity of BRC, suggesting that BRCA2 contains regions that both favor and disrupt homologous recombination. These activities might operate at different stages of DNA repair.
Both reports also provide insight into how the opposing activities of BRCA2 can be regulated – a phosphorylation event at TR2 results in the loss of its interaction with RAD51, acting as a turn-off switch. These findings advance our knowledge of BRCA2’s role in genetic stability, and contribute to our understanding of why mutations in BRCA2 increase the likelihood of cancer.
Author contacts:
Stephen West (Cancer Research UK, London, UK) Author paper [16]
Tel: +44 1707 625 868; E-mail: stephen.west@cancer.org.uk

Luca Pellegrini (University of Cambridge, UK) Author paper [17]
Tel: +44 1223 333 662; E-mail: luca@cryst.bioc.cam.ac.uk


Deciphering the histone code
A method to identify all modifications on histones, the proteins around which DNA is packed, is presented online. This study should allow researchers a better understanding of how genes are regulated by alterations to these proteins.
DNA holds all the information for the building blocks of life, but how a cell reads this genetic information depends on histones, and in particular on modifications to these histones. For example, the attachment of methyl groups to histones usually signals that a gene is silent, whereas the attachment of acetyl groups corresponds to gene activation. Scientists have dubbed the combinatorial use of histone modifications the ‘histone code’, but the extent to which different modifications are combined in the histone code is still unknown.
To help crack the code, Neil Kelleher and colleagues devised a method to identify all the possible modifications that occur on histones in a cell. First they separated different histone variants, depending on their degree of acetylation and methylation, by hydrophilic interaction chromatography, then they applied high-resolution tandem mass spectroscopy to identify all modifications on each variant and the exact residues carrying them. By using a mass spectrometry technique known as ‘top down,’ in which intact proteins are fragmented inside the mass spectrometer, they observed better preservation of modifications than traditional mass spectrometry methods looking at pre-digested proteins. For one particular histone alone, they found over 150 different patterns of modification.
This method helps to decipher the elements that make up the histone code and will allow researchers to relate the pattern of these modifications to the regulation of gene activity.
Author contact:
Neil Kelleher (University of Illinois at Urbana-Champaign, IL, USA)
Tel: +1 217 333 5071; E-mail: kelleher@scs.uiuc.edu

A red-letter day for brain connectivity

Insights into grapheme-colour synesthesia are presented in a paper of Neuroscience. People with this condition – who see a cascade of colours associated with individual letters when looking at a page of text – appear to have more neural connections in areas of the brain involved in word processing and binding perceptions together.
Romke Rouw and Steven Scholte used a technique called diffusion tensor imaging (DTI) to look at brain differences between grapheme-colour synesthetes and healthy controls without this condition. DTI allows non-invasive visualisation of the white matter tracts, or axons, connecting neural cell bodies. The researchers found that synesthetes had more axons connecting three brain areas: the right fusiform gyrus, near regions involved in word and colour processing, and the left intraparietal sulcus and frontal cortex, both part of a network of regions involved in binding and consciousness.
The study also found differences among the synesthetes, according to how they perceived the association between words and colours. Some synesthetes, known as projectors, report stronger experiences that are projected into the external world, while others, known as associators, report weaker experiences that appear in their ‘mind’s eye’. The degree of structural connectivity in a region known as the right temporal cortex was correlated with the strength of the synesthetic experience. These results suggest a two-stage model of synesthesia, with increased connectivity in some areas being important for generating perceptual binding, and connectivity in other areas determining the intensity of the resultant perceptions.
Author contact:
Romke Rouw (University of Amsterdam, The Netherlands)
Tel: +31 20 525 6742; E-mail: R.Rouw@uva.nl

Gene copy number and risk of autoimmunity

Individuals with fewer than two copies of the gene FCGR3B are more susceptible to a variety of autoimmune disorders, including lupus, according to a study.
Evidence is accumulating that, in addition to gene mutations, variation in the actual number of copies of individual genes can influence susceptibility to common diseases. It was previously shown that variation in the copy number of FCGR3B, a cell-surface receptor that contributes to the protective functions of the immune system, is associated with susceptibility to a kidney disease called glomerulonephritis. Timothy Aitman and colleagues now report that FCGR3B copy number variation is associated more broadly with autoimmune disorders, including lupus, microscopic polyangiitis, and Wegener’s granulomatosis. The small group of individuals who have no copies of FCGR3B have a dramatically elevated risk of autoimmune disease. This is among the first demonstrations that common naturally occurring variation in gene copy number can influence human susceptibility to disease.
Author contact:
Timothy Aitman (Imperial College, London, UK)
Tel: +44 208 383 4253; E-mail: t.aitman@csc.mrc.ac.uk

Glitter of gold traps microparticles


A simple technique for trapping suspended microparticles with a laser-illuminated array of gold microdots is demonstrated by Romain Quidant and colleagues online. The technique could prove useful for manipulating living cells in ‘lab-on-a-chip’ microfluidic systems.
Until now, the most promising approach to controlling cells and other micrometre-sized particles suspended in a liquid has been with so-called optical tweezers. These devices exploit the fact that such particles are attracted to and can be trapped by a focused light field. But one of their drawbacks is that they are bulky and complex devices to set up.
The technique demonstrated by Quidant and colleagues is much simpler. It relies on the fact that when a gold microdot or other metallic microstructure is illuminated with light, it will concentrate the optical field in its vicinity, similar in effect to the focusing power of a lens. By setting out an array of gold microdots on a glass slide and illuminating it with a laser, the authors effectively create an array of optical tweezers, which they use to trap microparticles suspended in a fluid droplet placed on the slide. Moreover, they show that they can use the array to selectively trap particles of a specific size from a collection of two different sizes, by controlling the size of the gold dots.
Author contact:
Romain Quidant (Institut de Ciencies Fotoniques, Barcelona, Spain)
Tel: +34 93 55 34 076; E-mail: romain.quidant@icfo.es

Cancer genomics: Modelling instability


A mouse model that for the first time mimics the levels of genomic instability in human cancers is presented online. The authors show that mouse and human tumours show similar genetic alterations, and suggest that future research should use this mouse model to understand the genetics of human cancer better.
Ronald DePinho and colleagues engineered lymphoma-prone mice with chromosomal instability to assess the usefulness of mouse models in cancer gene discovery. Using a comparative genomics approach they identified mutated genes in the model that are also altered in human T-cell acute lymphoblastic lymphomas and/or in a diverse range of other tumours. The researchers demonstrate a complexity and comparability in the human and mouse oncogenes that they believe means mouse models of tumours with a high degree of genomic instability will be a valuable resource for investigating complex human cancer genomes.
Author contact:
Ronald A DePinho (Dana Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 6085; E-mail: ron_depinho@dfci.harvard.edu

Evolution: Paddlefish clues to limb development
The limbs of tetrapods — land-living vertebrates — are usually thought to have been evolutionary innovations unique to that group. However, traces of limbs can be found in the development of primitive ray-finned fishes, according to a report.
The perceived uniqueness of the tetrapod limb may be a reflection of comparisons with fishes, notably the zebrafish (Danio rerio), which is often used as a model organism in embryological studies. However, the zebrafish is rather highly evolved, meaning that rather than lacking vestiges of limbs to begin with, it could have lost them during its ancestry. This latter possibility seems most likely following Neil Shubin and colleagues' study of Hox-gene expression in the development of the fins of a 'living fossil', the paddlefish Polyodon spathula.
Polyodon is one of the few relics of a type of bony fish common in the seas in the Palaeozoic era, more than 250 million years ago. Hox-gene expression in the developing fins of Polyodon shows patterns long considered to be tetrapod hallmarks. This finding demonstrates that some aspects of limb development are primitive and held in common by all bony fish — but have been lost in highly evolved fishes such as the zebrafish.
CONTACT
Neil Shubin (University of Chicago, IL, USA)
Tel: +1 773 834 7472; E-mail: nshubin@uchicago.edu

Optical materials: Semiconducting nanocrystals light up the way

A new type of nanocrystal that can be used as a laser material is reported in Nature magazine. 'Soft' optical materials like this can easily be processed in solution, offering flexibility for laser design, and the devices may find use in applications including lab-on-a-chip technologies and quantum information processing devices.
Semiconductor nanocrystals have excellent light-emitting properties, making them good candidates for use in laser applications. But achieving the crucial condition for lasing — optical amplification — has proved problematic: normally the nanocrystals need to contain at least two excitons (electron–hole pairs, which are the precursors for light emission in semiconductors), but owing to the nanocrystal’s tiny size, the excitons annihilate each other before optical amplification can occur.
Victor I. Klimov and colleagues circumvent this problem by designing nanocrystals with cores and shells made from different semiconductor materials, in such a way that electrons and holes are physically isolated from each other. In such engineered nanocrystals, only one exciton per nanocrystal is required for optical amplification, as has here been experimentally demonstrated by Klimov and colleagues. This opens the door to practical use in laser applications.
CONTACT
Victor I. Klimov (Los Alamos National Laboratory, NM, USA)
Tel: +1 505 665 8284; E-mail: klimov@lanl.gov

Todd D. Krauss (University of Rochester, NY, USA) N&V author
Tel: +1 585 275 5093; E-mail: krauss@chem.rochester.edu

Biophysics: Clustering key to membrane remodelling
A sophisticated simulation study reveals a trick that many membrane-bound proteins could use to vastly amplify their own effect on the shape of the membranes they are interacting with.
Biological membranes are much more than passive physical barriers: changes in their shape are linked to important cellular tasks such as endocytosis and protein sorting. It’s known that specialized proteins can sense and create membrane curvature, but the energy needed to accomplish complex membrane remodelling — large changes in membrane shape or topology — is only available when several proteins act together. But how do they coordinate their action?
Kurt Kremer and colleagues now show that a single protein interacting with a membrane causes local changes in membrane shape. Importantly, this attracts other proteins in the vicinity, which then cluster together yielding enough energy for the membrane to be remodelled, allowing, for example, vesicles to be formed.
CONTACT
Kurt Kremer (Max-Planck-Institut fur Polymerforschung, Mainz, Germany)
Tel: +49 6131 379 140; E-mail: kremer@mpip-mainz.mpg.de

Michael M. Kozlov (Tel Aviv University, Israel) N&V author
Tel: +972 3 640 7863; E-mail: michk@post.tau.ac.il

Extreme weather: A look from the lagoon
Changes in the El Niño/Southern Oscillation and the strength of the West African monsoon have played an important part in controlling the frequency of intense hurricanes in the tropical North Atlantic over the past 5,000 years, a study suggests.
Jeffrey P. Donnelly and Jonathan D. Woodruff constructed a long-term record of intense hurricane activity in the western tropical North Atlantic Ocean. Storms associated with intense hurricanes that strike the island of Vieques in Puerto Rico deposit layers of coarse, sandy material in a lagoon, so the authors used sediment cores from the lagoon to reconstruct the frequency of intense hurricanes in this area over the last 5,000 years.
Their record shows striking similarities to records of El Niño events and rainfall in tropical Africa, suggesting that changes in the El Niño/Southern Oscillation and the strength of the West African monsoon had an important role in controlling the frequency of intense hurricanes in the tropical North Atlantic over this interval.
The lengthy time-interval studied helps to clarify the factors that control hurricane activity, because instrumental records only cover the past few decades. Furthermore, the results suggest that it is important to understand how the El Niño/Southern Oscillation and the West African monsoon will respond to future climate change to accurately predict changes in intense hurricane activity.
CONTACT
Jeffrey P. Donnelly (Woods Hole Oceanographic Institution, MA, USA)
Tel: +1 508 294 2994; E-mail: jdonnelly@whoi.edu

Crows are smart! Research group at Keio University succeeds in drawing up the world’s first stereotaxic atlas of a crow
Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of Keio University and his group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Crows are known to be smart, and the findings proved that the pallium of the crow brain, which is related to intellectual activities, is well developed.

It has been known that the brain of a crow weighs 10-13g, very large compared to its total body weight. However, the details, such as which part of the brain is largely developed, were not clear. Prof. Shigeru Watanabe and Associate Prof. Eiichi Izawa of the Faculty of Letters and their group became the first in the world to succeed in drawing up a stereotaxic atlas of a crow. Recent observations had shown that crows have intelligence comparable to primates and have skills of tool-making and deceiving others. Prof. Watanabe and Associate Prof. Izawa clarified the total picture of the crow brain in detail to prove these observations, and the research can be applied in neuroscientific experiments in the future. These findings can be a breakthrough to finding out the brain evolution of animals including human beings.
1. About the stereotaxic atlas
The stereotaxic atlas is indispensable for studies of the brain. This is similar to a 3-dimensional map of a cross-section of the brain of fixed coordinates. By using this method, it is possible to identify the exact placements inside the brain. This stereotaxic atlas of the jungle crow was released on 14 May at http://www.cirm.keio.ac.jp/db/bird_brain, and will appear in “Integration of comparative neuroanatomy and comparative cognition” (Keio Univ. Press) to be published in the near future.
2. Characteristics of the crow brain
The crow is known to have a large brain compared to its body weight, and to have outstanding cognitive abilities. The stereotaxic atlas of the crow shows that brain areas called ‘pallium’ corresponding to the mammalian cortex, which controls thinking, learning and feeling, makes up a large portion of the brain, and within the ‘pallium’, the dorsal part which is related to intellectual activities, is large and well developed. This area is thought to be relevant to the association area (where multiple information such as visual or auditory signals are integrated) of the cerebral cortex in mammal brains including humans, and enables the crow to process complicated information. Crows are known to be smart, and the new completion of the stereotaxic atlas of the crow proved this.
3. Methods for drawing up the stereotaxic atlas
The research started with developing a stereotaxic holder to keep the crow brain in a fixed position. Stereotaxic holders for mice/rats and pigeons are commercially available, but for crows, it had to be custom-made. The brain was frozen under -20℃ and sliced into thin plates. The plates were then stained with cresyl violet for Nissle substance and luxol fast blue for myelinated fibers. The plates were examined under a microscope to separate the nerve cells according to density. At the same time, imaging of the plates were done to create an atlas and to name each group of nerve cells. The same process was repeated for all the plates of the crow brain from the front to the back, sliced in the thickness of 1mm. The atlas was completed by combining these data.
This research is part of the 21st Century COE Program Keio University Graduate School Toward an Integrated Methodology for the Study of the Mind. The Center of Excellence was selected by the 21st Century COE (Center of Excellence) Program of the Ministry of Education, Culture, Sports, Science and Technology toward an integrated methodology for the study of the mind. The newest findings in neuroscience, behavioral genetics are combined with philosophy, linguistics, information science and representational theories.
Inquiries: Mr. Ogawa or Ms. Kawagoe, Office of Communications and Public Relations, Keio University
TEL: ＋81-3-5427-1541 FAX: ＋81-3-5441-7640
E-mail: m-koho@adst.keio.ac.jp http://www.keio.ac.jp/

IMMUNOLOGY : Another immune evasion strategy by HIV

Interaction of the human immunodeficiency virus (HIV) with dendritic cells—a specialized type of immune cell—circumvents immune activation and greatly enhances infection of T lymphocytes, reports a study to be published in the June issue of Nature Immunology.
Dendritic cells are required to initiate immune responses, and as targets of HIV infection, these cells are important contributors to HIV pathogenesis. Alison Simmons and colleagues evaluated the effect of HIV interaction with DC-SIGN, a protein receptor found largely on the surface of dendritic cells. HIV binding to DC-SIGN elicited a signalling pathway that prevented dendritic cells from actively stimulating subsequent immune responses. In addition, the authors show that HIV–DC-SIGN interaction can lead to transfer of virus to nearby T lymphocytes that then become infected leading to a burst of HIV production.
These results reveal how HIV can both evade dendritic cell immune activity and amplify its own replication. With nearly 40 million people world-wide currently living with HIV-AIDS, understanding the myriad ways that HIV can modulate immune responses is of paramount importance.
Author contact:
Alison Simmons (Weatherall Institute of Molecular Medicine, Oxford, UK)
Tel: +44 1865 222 616; E-mail: asimmons@hammer.imm.ox.ac.uk

Additional contact for comment:
Anthony Cunningham (Westmead Millennium Institute, Australia)
Tel: +61 2 9845 9005; E-mail: tony_cunningham@wmi.usyd.edu.au

Gene combinations influence AIDS progression

Different combinations of genetic variants of two modulators of the innate human immune system strongly influence AIDS progression in HIV-positive individuals, according to a study.
Natural killer cells are part of the antiviral immune response, and their activity is controlled by receptors called KIRs that are present on the cell surface. The KIR receptors that inhibit natural killer cell activity (KIR3DL1) are triggered by HLA-B molecules, which are presented by other cells of the immune system. Mary Carrington and colleagues examined variation in the genes encoding KIR3DL1 and HLA-B in more than 1,500 HIV-positive individuals, and found that particular combinations of variants conferred protection against AIDS progression.
These results may explain at least part of the variability in progression of the disease in infected individuals. The authors also note that the observed rapid evolution of these genes may be driven by pathogens such as HIV.
Author contact:
Mary Carrington (National Cancer Institute, Frederick, MD, USA)
Tel: +1 301 846 1390; E-mail: carringt@ncifcrf.gov

Nanotubes sort out their left and right


Left- and right-handed carbon nanotubes can be separated from one another, according to a paper. Although nanotubes have previously been sorted on the basis of their diameter or length, this method is the first to discriminate between those with opposite helical twists.
Some molecules, which are known as ‘chiral’, can exist as mirror-image forms that cannot be superimposed on each other. Louis Pasteur was, in 1849, the first to separate such molecules, by meticulously sorting asymmetric crystals of tartaric acid by hand, using tweezers and a microscope. Following in his footsteps, Naoki Komatsu and co-workers designed pairs of chemical ‘nano-tweezers’ that can selectively pluck either left- or right-handed nanotubes from a mixture.
The ability to separate carbon nanotubes — one of nanotechnology’s most promising building blocks — in this way will lead to a better understanding of their optical properties, and may offer unique opportunities for photonics and quantum optics.
Author contact:
Naoki Komatsu (Shiga University of Medical Science, Otsu, Japan)
Tel: +81 77 548 2102; E-mail: nkomatsu@belle.shiga-med.ac.jp

CHEMICAL BIOLOGY : A little sugar for the brain

The amount of sugar on proteins inside neural cells changes in response to brain stimulation, which implicates sugar modification as a new player in brain signalling, according to a paper to be published in the June issue of Nature Chemical Biology. Changes in the levels of phosphorylation of serine and threonine residues have a well-known role in cell signalling. Although most glycosylation, or modification of proteins by the attachment of sugars, occurs on proteins outside the cell, one sugar modification, called O-GlcNAc, can be attached to serine or threonine residues of proteins inside cells. Because phosphorylation and O-GlcNAc modifications occur on exactly the same amino acid side chains, O-GlcNAc could be critical in cellular signalling. However, a lack of tools to identify the precise positions of O-GlcNAc modifications in vivo has made it difficult to investigate this hypothesis.
Linda Hsieh-Wilson and colleagues have now developed a proteomic method that uses mass spectrometry to determine in vivo O-GlcNAc levels. When rats were injected with an excitatory stimulus, the authors identified changes in the sugar levels at specific sites of proteins found in the brain. With this information, it will now be possible to investigate the exact role O-GlcNAc plays in brain function.
Author contact:
Linda Hsieh-Wilson (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 6101; E-mail: lhw@caltech.edu

Unexpected biodiversity springs from the depths
Five-hundred and eighty-five new species of crustacean have been found in the depths of the Southern Ocean, thanks to three sampling expeditions set up as part of the ANDEEP (Antarctic benthic deep-sea biodiversity) project. Unexpected levels of biodiversity were found in this dark and largely unstudied place, challenging assumptions that deep sea diversity is depressed in this area.
On their expeditions, Angelika Brandt and colleagues collected biological specimens and environmental data from different regions 774 to 6,348 metres under the surface of the Weddell Sea and adjacent areas. The Weddell Sea is an important source of deep water for the rest of the ocean and provides a possible route for species to enter the deep water. In line with this, the team found deep-sea faunas that were also found in adjacent shelf communities and in other oceans.
They spotted 674 species of isopod — a diverse order of crustaceans — of which over 80% were new to science. In some regions, groups of slope-dwelling isopods and marine worms included species that had invaded from the Southern Ocean’s deep continental shelf. Species living in the deepest parts of the Weddell Sea tended to have strong links to other oceans, particularly if they were good dispersers, like certain amoeboids. But poor dispersers, such as isopods, nematode worms and seed shrimps, were Southern Ocean-specific species.
CONTACT
Angelika Brandt (University of Hamburg, Germany)
Tel: +49 40 42838 2278; E-mail: abrandt@zoologie.uni-hamburg.de

Materials: Silicon in a spin
The first silicon-based spintronics device reported. Spintronics, an emerging technology that uses the quantum spin states as well as (or instead of) the charge states of electrons, offers another level of control over electronic devices. So with silicon already at the forefront of conventional electronics, devices like this could find themselves integrated with standard silicon technology.
Researchers have been trying to make devices that can transport electronic signals with all of the electrons spun in one direction only. But finding the right combinations of materials to do this efficiently has proved tricky. Ian Appelbaum and colleagues have achieved this by sandwiching an extra layer inside their device. The extra layer, made from aluminium and iron cobalt sits between an insulating barrier and the silicon, where it filters out electrons of a particular spin.
CONTACT
Ian Appelbaum (University of Delaware, Newark, DE, USA)
Tel: +1 302 831 3295; E-mail: appelbaum@ee.udel.edu

Igor Zutic (State University of New York at Buffalo, NY, USA) N&V author
Tel: +1 716 645 2017 x183; E-mail: zigor@buffalo.edu

Infectious diseases: Global early-warning system needed
Researchers are calling for a global early-warning system to identify the sources of future human infectious disease. analysis compares the origins of temperate and tropical infectious diseases, and highlights how little we know about their evolution.
Most major human infectious diseases have animal origins, yet we continue to be bombarded by new animal pathogens, jumping across species barriers. So Jared Diamond and colleagues want to see a systematic ongoing global effort monitoring for emergent animal pathogens that could infect humans. People with high levels of exposure to wild animals, such as hunters, zoo workers and wildlife veterinarians, should be regularly screened, they say.
The team made their request after comparing the characteristics and origins of 15 temperate (such as whooping cough) and 10 tropical diseases (such as cholera). Most of the diseases studied arose in Africa, Asia and Europe, but the reasons for their emergence differed between regions — infections from animal and insect vectors, for example, were more common in the tropics.
The review reveals “big gaps in our understanding” of the origins of even established major infectious diseases, such as AIDS, cholera and tuberculosis. So alongside a global early-warning system for new human infectious diseases, the authors would also like to see more research to clarify the origins of existing infectious diseases. Such work could boost understanding of how diseases emerge and suggest new laboratory models for studying public health threats.
CONTACT
Jared Diamond (University of California, Los Angeles, CA, USA)
Tel: +1 310 825 6177; E-mail: jdiamond@geog.ucla.edu

Nathan Wolfe (University of California, Los Angeles, CA, USA) Co-author
Tel: +1 310 794 7538; E-mail: nwolfe@ucla.edu

Planetary science: Enceladus' daily grind

Scientists may have worked out what powers the plumes of gas seen escaping from the surface of one of Saturn's moons. The energy may be generated by massive ice sheets grinding together, with the vapour produced being released through rifts that open and close periodically, papers suggest.
When Cassini flew by Enceladus, a small icy satellite of Saturn, a couple of years ago, cameras snapped active vapour plumes thought to emanate from rifts in the crust dubbed 'tiger stripes.' Francis Nimmo and colleagues now suggest that these 'tiger stripes' are like strike-slip fault zones, with sheets of ice grinding back and forth against one another. This, they say, could generate enough energy to power the gas plumes.
Terry A. Hurford and colleagues show that as Enceladus orbits Saturn, the parent planet's tides make the satellite's ice flex. This, they believe, causes the 'tiger stripes' to open and close periodically, exposing volatiles and allowing them to be released.
Tidal heating was previously proposed as a potential mechanism to explain Enceladus' vapour plumes, but scientists debate whether the energy generated from tidal heating is sufficient. The two new papers offer a plausible alternative.
CONTACT
Francis Nimmo (University of California, Santa Cruz, CA, USA) Author paper [2]
Tel: +1 831 459 1783; E-mail: fnimmo@es.ucsc.edu

Terry A. Hurford (NASA Goddard Space Flight Center, Greenbelt, MD, USA) Author paper [3]
Tel: +1 301 614 6455; E-mail: hurfordt@core2.gsfc.nasa.gov

Andrew J. Dombard (Johns Hopkins University, Laurel, MD, USA) N&V author
Tel: +1 240 228 1651; E-mail: andrew.dombard@jhuapl.edu

Regeneration: Hope for new hair

Adult mice can regenerate hair follicles and hair. The results help resolve a 50-year-long debate and may aid in the design of new treatments for wounds, hair loss and other degenerative skin disorders.
For half a century, most people believed that mammalian hair follicles form only during development, and that loss of adult follicles is permanent. George Cotsarelis and colleagues now show this is not the case, at least for adult mice with skin wounds. Wounding, they report, triggers new hair-producing follicles to form. Exposure to Wnt signalling — a genetic pathway involved in normal hair follicle development and cycling — following wounding increases the number of regenerated hair follicles. And Wnt signalling inhibition after regrowth of the epithelium prevents new follicles from forming.
The results suggest that mammalian skin can respond to wounding with plasticity and a much greater regenerative capacity than was previously believed. It's thought that wounding triggers an embryonic-like state in the skin which provides a window for hair follicle regeneration via the Wnt signalling pathway.
CONTACT
George Cotsarelis (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 898 9967; E-mail: cotsarel@mail.med.upenn.edu

Cheng-Ming Chuong (University of Southern California, Los Angeles, CA, USA) N&V author
Tel: +1 323 442 1296; E-mail: chuong@pathfinder.usc.edu

Bagoong: Good for the Brain
A study shows that the traditional fish/shrimp paste condiment, or bagoong, of the Philippines contains the beneficial omega-3 fatty acids. In its analysis, it was found that among the samples of bagoong, shrimp paste has the highest omega-3 content.
The famous Bagoong, also referred to as fish or shrimp paste, is one of the traditional flavor extenders used in the Philippines. It has several variations according to the type of fish used, color, and taste. Bagoong is prepared by fermenting the fish or shrimp in high concentrations of salt for several months. Consumed either as a complement of green mangoes or as a seasoning to some Filipino delicacies such as pinakbet, little is known about the nutritional content of these condiments since they are usually sold without labels in local markets.
Fish and other marine food resources are known to be good sources of long-chain ω-3 (omega-3) polyunsaturated fatty acids. One in particular is the all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA), a variant of the long-chain ω-3 fatty acid, which is essential to the neural development of growing infants especially in brain and retina development. Sufficient amount of DHA is required for an active brain function throughout a human’s lifespan. DHA has also been found to lower blood pressure and chances of occurrence of heart disease and mental illness. Though high levels of DHA are produced during pregnancy and during the first two months of infancy, the normal human body condition can only manufacture these fatty acids metabolically in small amounts. DHA must then be acquired from the diet or produced through the consumption of ω-3 precursors such as α-linolenic acid found in seeds and nuts.
The composition of bagoong suggests the possibility that the said condiment may be a dietary resource of long-chain ω-3 polyunsaturated fatty acids. In the study “Polyunsaturated fatty acid contents of some traditional fish and shrimp paste condiments of the Philippines,” scientists Nemesio Montaño, Grace Gavino and Victor C. Gavino assess the fatty acid composition of various types of fish and shrimp paste in reaction to the brine solution used for fermentation.
Montaño’s team gathered samples of six types of fish and shrimp paste condiments from a public market in Bolinao, Pangasinan located at Western Luzon of the Philippines. The vendors of these products were interviewed regarding their preparation process of bagoong. The general preparation of bagoong according to them is that fish or shrimp fry are deposited alternately in layers with salt in ratios of three to four parts of salt to one part of fish or shrimp fry. The mixture is then incubated at ambient temperature in a specific period of time depending on the fish type used. The fish types used in the collected samples were verified through visual investigation. The samples were found to be made from Dalagang bukid (Fusiliers, Caesio spp.), Dilis (Silver sprat, Spratelloides gracillis), Padas-1 (Fuscescens rabbitfish, Siganus fuscescens), Padas-2 (Forktail rabbitfish, Siganus argenteus), Terong (Fusiliers, Pterocaesio spp.) and Alamang (Shrimp fry, Acetes spp.). Samples were analyzed fresh or freeze-dried. The composition of fresh untreated alamang was also compared with the composition of salt-treated alamang.
Fatty acid composition, salt content, moisture and water activity of the fish/shrimp paste samples were measured to examine if the salinity of the paste condiments and the oxidation process significantly affect the fatty acid content of the fish and shrimp fry. Ash and fat content were also studied to look further into the composition of bagoong. The salt content of the samples was determined using the Mohr Method [1] while moisture was calculated from the sample’s weight loss when dried. Water activity was determined by equilibration with the salt solution. The dried samples were then reduced to ashes to measure the ash content. Fat content was measured by Soxhlet extraction [2] of the freeze-dried samples and the fatty acid composition was determined using an adaptation of a direct methylation procedure on the sample followed by gas chromatography.
Findings show that the salt content of the bagoong samples does not tally with the ratio of salt to fish/shrimp fry given by the vendors. Salinity was found to range from 19 to 24%, which greatly differs from the 60 to 80% accounted from the vendors’ statement. The alamang condiment was also found to contain the highest level of DHA ω-3 polyunsaturated fatty acids among the samples followed by Padas-1. The Dalagang bukid paste condiment, on the other hand, has the lowest. According to Dr. Montaño, this may be explained by the phytoplanktons and bacteria the shrimp fry consume which could have produced the high levels of long-chain polyunsaturated fatty acids.
References:
1. Thomson Healthcare, PDRhealth. “Docahexaenoic Acid (DHA).”
2. DHA/EPA Omega-3 Institute. “DHA for Optimal Brain and Visual Functioning.“
3. The Kushi Institute of Europe, Encyclopedia. “Fats.”
4. University of Canterbury, Christchurch New Zealand. “Determination of Chloride Ion Concentration by Titration (Mohr’s Method).”


By MMRParreño

___________________________________________________________________
[1] Mohr Method is the process of determining chlorides in bagoong sample using titration with silver nitrate and indicator potassium chromate. The pH level of the sample to be tested should be between 6.5 to 10 for more accurate readings.

[2] Soxhlet Extraction is the process of extracting fat from the freeze-dried bagoong sample using low-boiling petroleum ether as solvent.

Gender-specific differences fuel biodiversity

Many factors, such as habitat, behaviour and diet, contribute to biological diversity. But researchers now have an unexpected addition to this list — sexual differences. A study of the Anolis lizards of the Greater Antilles suggests that morphological differences between males and females are linked to increased biodiversity.
The Anolis lizards of Puerto Rico, Jamaica, Cuba and Hispaniola evolved independently on their respective islands into species that occupy particular niches, such as the short-legged twig dwellers and the long-legged open space dwellers. But males and females of the same species can be very different — in some species the sexes are the same size, but in others adult males can be three times bigger than females.
Marguerite A. Butler and colleagues studied five sexually dimorphic characteristics from male and female adults of different niche specialists living on two of the islands. They find that sexual dimorphism contributes substantially to biodiversity, helping to fuel the bursts of ‘adaptive radiation’ that produced the different niche-adapted species.
Most studies of adaptive radiation ignore sexually dimorphic traits, the authors say. But its place in evolutionary ecology should not be underestimated.
CONTACT
Marguerite A. Butler (University of Hawaii at Manoa, Honolulu, HI, USA)
Tel: +1 808 956 4713; E-mail: mbutler@hawaii.edu

Oceanography: Oceanic short circuit

Researchers have discovered a 'short circuit' in the circulation of the world's oceans that allows cold waters that sink to the abyss to return to the surface more rapidly than previously thought. Understanding oceanic circulation is important because it transports heat, carbon and nutrients around the globe and therefore plays a central role in Earth's climate.
Ocean mixing in the current that flows around Antarctica has a key role in global ocean circulation as it influences the rate at which water sinking to the deep ocean at high latitudes returns to the surface in the Southern Ocean. But the rates of mixing processes that occur in the current and the induced upwelling are not well known. Alberto C. Naveira Garabato and colleagues studied the spread of helium released from submarine volcanoes to measure the rates of mixing and upwelling in the southwest Atlantic sector of the current.
Their results indicate that the rough topography of the ocean floor in this region leads to both rapid mixing across density surfaces and rapid upwelling along density surfaces, which together create a 'short circuit' in the global oceanic overturning circulation.
CONTACT
Alberto C. Naveira Garabato (University of Southampton, UK)
Tel: +44 23 8059 2680; E-mail: acng@noc.soton.ac.uk

Planetary science: Extrasolar planet mirror ball
An extrasolar 'hot Jupiter' planet may act like a giant mirror ball, re-radiating almost all of its incident energy back out to space, suggests a paper. But a second paper, tells a very different story, making 'hot Jupiters' seem all the more intriguing and complex.
'Hot Jupiters' are extrasolar planets whose mass is similar to that of Jupiter, but which orbit much closer to their parent star. Joseph Harrington and colleagues studied one such planet and found that it acts almost as a mirror, a bizarre observation as one would expect the planet to absorb at least some heat.
But Heather A. Knutson and co-workers found that a different 'hot Jupiter' can redistribute heat around its surface. The team effectively crudely 'mapped' the temperature distribution across the planet. Their data suggest that energy absorbed by the dayside of the planet can be fairly efficiently redistributed throughout the planet's atmosphere.
CONTACT
Joseph Harrington (University of Central Florida, Orlando, FL, USA) Author paper [2]
Tel: +1 407 823 3416; E-mail: jharring@phsyics.ucf.edu
Heather A. Knutson (Harvard University, Cambridge, MA, USA) Author paper [3]
Tel: +1 617 223 1723; E-mail: hknutson@cfa.harvard.edu

Adam Burrows (University of Arizona, Tucson, AZ, USA) N&V author
Tel: +1 520 621 1795; E-mail: aburrows@as.arizona.edu

Genetics: Marsupial genome sequenced
The first high-quality draft of a marsupial genome sequence is revealed.The genome of the grey, short-tailed opossum (Monodelphis domestica) offers interesting insights into the genetics of the immune system and the X chromosome.
Kerstin Lindblad-Toh and colleagues identified a wide range of immune genes. Some seem to be marsupial-specific, whereas others are shared with placental mammals. This, alongside the discovery of a novel type of T-cell receptor, indicates that marsupials had already evolved a complex immune system when they diverged from the placental mammal lineage some 180 million years ago — a suggestion that is at odds with previous claims of a primitive immune system.
The results also suggest that random inactivation of the X chromosome — a phenomenon seen in placental mammals whereby one random copy of the X chromosome is switched off to avoid a double dose of 'X genes' — appeared alongside the evolution of a complex genetic locus called the X inactivation centre (XIC). The XIC is lacking in the opossum genome, a finding that may help to explain why, in the opossum, it's always the paternally derived X chromosome that is silenced.
The newly sequenced genome seems to contain 18,000–20,000 protein-coding genes, most of which have counterparts in placental mammals. Opossum-specific genes mostly originate from the expansion and rapid turnover of gene families involved in immunity, sensory perception and detoxification.
The sequencing of the opossum genome marks an important point in genetics research and not just because of the special place occupied by the marsupial in the evolutionary tree. The animals provide a good model of malignant melanoma, and are useful in studies of regeneration because newborns can heal complete transections of spinal cord.
CONTACT
Kerstin Lindblad-Toh (Broad Institute of MIT and Harvard, Cambridge, MA, USA)

Nicole Davis (Scientific Communications Specialist, Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Tel: +1 617 258 0952; E-mail: ndavis@broad.mit.edu

Geoff Spencer (Public Affairs Specialist, National Human Genome Research Institute, NIH, Bethesda, MD, USA)
Tel: +1 301 451 8325; E-mail: spencerg@mail.nih.gov

Leo Goodstadt (MRC Functional Genetics Unit, University of Oxford, UK) Co-author
This author can be contacted through the MRC press office:
Tel: +44 20 7637 6011; E-mail: press.office@headoffice.mrc.ac.uk