Virus-based screen for ion channel modulators
A virus-based method that screens for chemical or genetically-encoded inhibitors of ion channels. Ion channels are cell membrane-spanning proteins that, when activated, allow the influx of ions. They encompass a large family of over 400 proteins and play key roles in maintaining cellular function. While blocking their activity has proven useful for certain medical applications, these drugs usually elicit severe side effects due to their wide range action and lack of selectivity for the intended cell alone.
Joseph Glorioso and colleagues wanted to find more specific channel modulators and set up a virus-based screen in which the virus level is an indicator for inhibitor efficacy. They reasoned that overexpression of an ion channel in cells via a virus would be detrimental to the cell and consequently impede viral replication; while the presence of an inhibitor of channel function would keep the cells healthy and allow replication. The advance over other screens for channel inhibitors is that the technique can easily be adapted to screen for genetically-encoded inhibitors by coinfection of a second virus that encodes the inhibitor. The inhibitor’s DNA can then be easily retrieved from the viral genome.
This method can easily be scaled up to screen whole DNA libraries that express a wide range of potential channel modulators. These genetically encoded inhibitors will help reveal the biology behind channel regulation and are likely to lead to more specific inhibitors.

Author contact:
Joseph Glorioso (University of Pittsburgh School of Medicine, PA, USA)
Tel: +1 412 648 8105; E-mail: glorioso@pitt.edu

Fast and low cost Photographic Method
Researchers in the Philippines have revealed that a fast and low cost photographic method is just as effective as the more expensive videographic method in assessing the condition of coral reef benthic communities. Comparison Between Videographic and Photographic Methods in Assessing Coral Reef Benthic Communities by Patrick C. Cabaitan, Wilfredo Y. Licuanan, and Edgardo D. Gomez
Continuous degradation of coral reefs creates a need for techniques that can assess reef conditions rapidly and efficiently. The Video transect survey is commonly used to monitor benthic communities because it is rapid, provides a permanent historical record of the data, and can help minimize observer bias. But this technology is not readily available to most research institutions because of its high cost.
In this study, a low cost photographic method was used to survey benthic communities in the subtidal flat inside Caniogan Marine Sanctuary, Tondol, Anda, Pangasinan. Results from this method were then compared with those from videographic methods.
For the low cost photographic method, ten regularly spaced shots were directly taken from each 5m transect, totaling to 100 frames. Ten 5m x ~0.25m video transects were also run over each of the twenty selected patch reefs, covering the whole demarcated area. Ten regularly spaced frames were then taken from the videotape in each transect, totaling to 100 frames in each patch reef. In the laboratory, all frames were analyzed using the systematic 5-point method.
Both methods yielded comparable time in field data collection. However, videographic method demanded more time in post-collection computer analysis and it is more costly due to the required additional computer software and hardware. Pairwise T-tests and Analysis of similarities (ANOSIM) revealed that both methods gathered similar results in terms of the diversity (P>0.05) and in terms of percentage composition (P>0.05) of life forms recorded, suggesting that both can be used interchangeably in benthic community surveys.
(Science Diliman)E-mail: rduo.ovcrd@up.edu.ph
Telephone:+63 2 - 927-2309
Fax:+63 2 - 927-2568

Commencement of Second Life Joint Research
Keio University and Dentsu Announce the Commencement of Second Life Joint Research -- Keio University Second Life Campus to Hold Japan’s First Metaverse-Based University Course --
Keio University (President: Yuichiro Anzai; Head Office: Tokyo) and Dentsu Inc. (President & COO: Tatsuyoshi Takashima; Head Office: Tokyo; Capital: 58,967.1 million yen) announced today that they will conduct joint research covering a number of issues relating to metaverses, and particularly Second Life® (See Note 1), a 3-D virtual community that has gained worldwide popularity. Planned research topics include issues on social systems, distance learning and continuing education, the potential for marketing activities within a metaverse, and the potential for technological development.
As a facility to carry out their joint research, Keio University and Dentsu plan to establish the Keio University Second Life® Campus within Virtual Tokyo (See Note 2), which Dentsu will open in August this year as a virtual city within the Second Life® metaverse. Through demonstration tests conducted in the Keio University Second Life® Campus, the joint research group aims to contribute to finding solutions to a range of issues relating to virtual societies. In addition, the joint research group plans to study the potential for educational content within 3-D virtual communities and consider various aspects about the future of education.

Outline of the Joint Research
Keio University Dentsu and will establish a joint research facility, Keio University Second Life® Campus, within Virtual Tokyo. Virtual land for the campus as well as authority to manage the campus will be provided by Dentsu to Keio University Research Institute at SFC. The research group will utilize this land to conduct their research. The land area allocated for the campus will be 1 SIM, which is the standard land unit in the Second Life® metaverse and is equal to 256 x 256 meters (16 acres).

Within this virtual space, the research group will conduct the following research

(1) Within the Keio University Second Life® Campus, the research group plans to explore new education possibilities by utilizing the experience Keio University has built up in distance teaching methods, for instance, through operating the Keio University SFC Global Campus (See Note 3). Utilizing the educational video content Keio University has accumulated until now, the research group plans to examine the
potential for Second Life® in the education field. This will be the first time for a university in Japan to offer lectures from regular university courses within Second Life®.
(2) The research group will conduct research within the Keio University Second Life® Campus and Virtual Tokyo on the behavior of Second Life® consumers and economic activities such as virtual currencies. Utilizing the Linden Dollar, the virtual currency circulating within Second Life®, the research group will study such areas as the virtual economic mechanism, analysis of consumer behavior, and legal or ethical issues within the metaverse. The research group also plans to collaborate with the makers of Second Life®, Linden Labs, in research on technical aspects of Second Life®.

Research Group Participants
A number of researchers from the Keio Research Institute at SFC, based at the Keio University Shonan Fujisawa Campus, will participate in the research. These researchers include such specialists in Internet, digital media, and other social applications for new technologies as Professor Jun Murai and Professor Masahiko Inakage from the Faculty of Environment and Information Studies; Professor Ikuyo Kaneko from the Graduate School of Media and Governance; and Professor Jiro Kokuryo from the Faculty of Policy Management.
From Dentsu, specialists in marketing and media content will participate in the joint research. Dentsu Group companies will also provide cooperation and support for the construction and operation of the virtual campus.

Note 1: Second Life® 3-D virtual community

Second Life® is a 3-D virtual community, created and operated by U.S.-based company Linden Lab, with a rapidly growing population from 100 countries around the globe. Residents of the Second Life®
metaverse themselves create and build the world that includes homes, vehicles, nightclubs, stores, landscapes, clothing, and games. The Second Life® Grid is a sophisticated development platform created by Linden Lab, a company founded in 1999 by Philip Rosedale, to create a revolutionary new form of shared 3-D experience. The former CTO of RealNetworks, Rosedale pioneered the development of many of today’s streaming media technologies, including RealVideo. In April 2003, noted software pioneer Mitch Kapor, founder of Lotus Development Corporation, was named Chairman. In 2006, Philip Rosedale and Linden Lab received WIRED’s Rave Award for Innovation in Business. Based in San Francisco, Linden Lab employs a senior team bringing together deep expertise in physics, 3-D graphics and networking.

Note 2: Virtual Tokyo
Virtual Tokyo is a comprehensive virtual city being created based on the concept of
"Vitality–Future–Tokyo.” It is a collaboration between Dentsu and Tetsuya Mizuguchi, CCO of Q Entertainment Inc. Virtual Tokyo will condense the images and energy of Tokyo and disseminate to the rest of the world the pop culture created within it. Virtual Tokyo will not be a one-way content source but provide a place for creators (users) to actively participate. By doing so, Dentsu wishes to recreate the
dynamism of Tokyo—an ever-changing city—within Second Life®. Virtual Tokyo will cover 85 hectares, making it one of the largest cities within Second Life®. It will comprise various zones, including a public zone with stadiums and museums, and other zones such as those focusing on education, experiential activities and commerce.

Note 3: Keio University SFC Global Campus (http://gc.sfc.keio.ac.jp/)
The Keio University Shonan Fujisawa Campus (SFC-GC) provides lectures that are shared globally and accessed by learners outside the university. It was opened in 2002 and from the 2002 autumn semester to the 2007 spring semester, 297 courses (each comprising 13 lectures) have been made available for access as approximately 4,000 video material content items. At present, Keio University runs the distance learning program, which allows people who are not Keio University students to utilize SFC-GC to enroll in courses. Furthermore, the content, which is provided free of charge, may be accessed without the need for user registration.
Contact: Rina Tanaka and Aiko Nakajima
Office of Communications and Public Relations
Keio University
Telephone: (813) 5427-1541
E-mail: m-koho@adst.keio.ac.jp

Climate change: Brown haze spells bad news



The haze of air pollution over the Indian Ocean may be causing as much lower atmospheric warming as the recent increase in anthropogenic greenhouse gases.
During 18 missions, Veerabhadran Ramanathan and colleagues simultaneously flew three lightweight unmanned aerial vehicles below, into and above the polluted ‘Brown Clouds’ over the Indian Ocean. Tiny instruments were deployed to measure aerosol concentrations, soot amount and solar fluxes, allowing the team to calculate atmospheric solar heating rates. Using model simulations, they conclude that atmospheric Brown Clouds enhance lower atmospheric solar heating by around 50 per cent.
Atmospheric Brown Clouds consist of a mixture of light-absorbing and light-scattering aerosols and so contribute both to atmospheric solar heating and to surface cooling. The combined effects are thought to have masked up to 50 per cent of the global warming attributed to the recent, rapid rise in greenhouse gases. This study helps to tease out the effects of atmospheric solar heating.
CONTACT
Veerabhadran Ramanathan (University of California San Diego, La Jolla, CA, USA)
Tel: +1 858 337 3114; E-mail: vram@fiji.ucsd.edu or vraman000@hotmail.com

Peter Pilewskie (University of Colorado Boulder, CO, USA) N&V author
Tel: +1 303 492 5724; E-mail: peter.pilewskie@lasp.colorado.edu

Earthquakes: Love and stress
Non-volcanic tremor and slip along a plate boundary can be triggered by shear stress, rather than fluid movement.The analysis of seismic data has revealed long-duration, low-amplitude tremor, similar to that seen below active volcanoes, but associated with plate tectonic boundaries, rather than volcanoes. Episodes of tremors and slow slip have been observed to last up to months, and can be associated with as much deformation as a magnitude-7 earthquake. Although observations of this type of tremor are increasing, the mechanism behind it remains unclear, with some researchers pointing towards slip along the plate interface, and others the movement of fluids.
Justin Rubinstein and colleagues examined seismic recordings associated with the 2002 Denali earthquake and found clear evidence of bursts of tremor having been triggered within the Cascadia subduction zone near Vancouver Island, Canada. These episodes seem to be triggered when the Love wave (surface seismic wave) displacements were to the southwest — parallel to the direction of plate convergence. They conclude that the tremor and possibly slow-slip events can be induced by shear stress increases along the subduction interface.
CONTACT
Justin Rubinstein (University of Washington, Seattle, WA, USA)
Tel: +1 206 685 7563; E-mail: justin@ess.washington.edu

Neuroscience: Deep brain stimulation in a minimally conscious state

The responses of a single patient in a minimally conscious state have improved with deep brain stimulation.During this intervention, the patient’s arousal level and motor control increased to the point that he was able to chew and swallow food.
‘Minimally conscious state’ refers to a level of consciousness characterized by intermittent evidence of awareness of oneself or the environment, and is distinct from persistent vegetative state or coma. At present there are no reliable means for improving recovery from this extended loss of consciousness, which can occur following traumatic brain injury, although recent evidence suggests some brain activity may be preserved in minimally conscious patients. In the current study, Nicholas Schiff and colleagues implanted electrodes into the brain of a 38-year-old male, six years after he suffered a severe brain injury that resulted in a minimally conscious state. The electrodes were used to stimulate an area known as the thalamus, on both sides of the brain, which has been suggested to have a role in arousal. The authors report that during periods of stimulation, the frequency of communicative behaviours, functional limb control and oral feeding increased.
The authors caution that the extent to which their results might apply to other patients is unknown, and that expectations raised by their findings should be tempered — the specific injury suffered and its effects on responsiveness will not be shared by all patients in a minimally conscious state. The present findings should, however, motivate further research into the mechanisms of recovery, as their replication could have important implications for clinical practice.
CONTACT

Nicholas Schiff (Weill Cornell Medical College, New York, NY, USA)

Joseph Fins (Weill Cornell Medical College, New York, NY, USA)

Ali Rezai (Cleveland Clinic Foundation, OH, USA)

Joseph Giacino (JFK Johnson Rehabilitation Institute / New Jersey Neuroscience Institute, Edison, NJ, USA)

Tunable light sources lose their mirrors

A tunable infrared source that is ‘mirror-free’ and easy to align has been experimentally demonstrated for the first time and could result in a new source of light that is small, inexpensive and convenient to use.
Optical parametric oscillators (OPOs) are useful in the fields of spectroscopy, chemistry and other disciplines because they offer tunable coherent light – narrow-bandwidth light that has radiation with all the waves vibrating in phase – with wavelengths ranging from 2 to 10 micrometres, filling gaps that can’t be served by other sources. Unfortunately, conventional designs are hard to align and miniaturize as, apart from a nonlinear crystal, they also contain a pair of mirrors that need to be very precisely located. Although ‘mirrorless’ designs have been theoretically proposed in the past, an experimental prototype has not been demonstrated to date.
Carlota Canalias and Valdas Pasiskevicius have built a device that is highly compact, easy to align and has the ability to tune wavelengths with high precision in the near- and mid-infrared wavelengths. Their OPO relies solely on subtle modifications to the nonlinear crystal itself, rather than mirrors. The result is a new breed of OPO that consists of just the nonlinear crystal and a pump laser.
Author contact:
Carlota Canalias (Royal Institute of Technology, Stockholm, Sweden)
Tel: +46 855 378 159; E-mail: cc@laserphysics.kth.se

Filipino Physicists Awarded a US Patent for a New Semiconductor Circuit Imaging Technique
A microscope imaging technique for visualizing and analyzing semiconductor integrated circuits developed by a team of scientists from the University of the Philippines’ National Institute of Physics was awarded a patent by the United States Patent and Trademark Office.
Imagine if our computers, cellular phones and other electronic gadgets cease to work due to failures in the circuits that run them. These failures in the minuscule wires that make up the semiconductor integrated circuits embedded in our electronic products must be detected in order to make sure that our prized gadgets function. To detect such failures, an effective technique for visualizing and analyzing circuits has been developed by a team of scientists from the University of the Philippines’ National Institute of Physics (UP NIP), namely: Dr. Ceasar Saloma, Dr. Vincent Ricardo M. Daria and Ms. Jelda Jane C. Miranda. This microscope imaging technique entitled “Method for Generating High Contrast Images of Semiconductor Sites via One-Photon Optical Beam-induced Current (IP OBIC) Imaging and Confocal Reflectance Microscopy” was awarded a patent by the United States Patent and Trademark Office last June 26, 2007.
Saloma, currently Dean of the College of Science of the University of the Philippines, is recipient of prestigious international awards for outstanding scientific work, among them the Galileo Galilei Award from the International Commission on Optics. Daria, Associate Professor at the UP-NIP is one of its most active researchers, and Miranda, who was part of its Experimental Optics Group now works for Intel Corporation. The US patent gives Saloma and his team an exclusive right to commercialize their invention in the United States without fear of infringement. The patent is effective for 20 years after the filing of application in December 09, 2006. For more details on the invention, you may check out the United States Patents and Trademarks Office website at http://patft.uspto.gov/.
The invention combines two existing imaging techniques called confocal reflectance microscopy and 1P-OBIC. It uses computer software to produce a high-contrast image mapping of the semiconductor and metal sites in an integrated circuit. The technique is a major breakthrough in the semiconductor industry. It is particularly useful in the manufacturing of microprocessors, integrated circuits and memories for computers, cellular phones and other electronic devices. Creating sharp visual images of semiconductor integrated circuits is important for failure analysis since one can track which part of the device would produce electrical current when hit by laser beam. The method facilitates accurate identification of semiconductor and metal sites in an integrated circuit. With this technique, defects in the circuit can be detected, thus ensuring quality control of such devices.
The main claims of the patent include a description of a technique that facilitates discrimination of these two types of materials in an integrated circuit. The claims also include a description of the optical layout for a generic confocal microscope that allows for simultaneous acquisition of reflectance confocal image and single-photon optical beam induced current (OBIC) image. Moreover, the patent includes an algorithm and software control for microscopic image acquisition for both confocal and OBIC image.
Applications of the patent extend to a fully integrated microscope system for failure analysis of integrated circuits by improved visualization and mapping of materials in a semiconductor device. The microscope extends to a system for measuring optical beam induced current of semiconductor materials. Further applications of the patent may include the construction of a general purpose Confocal Reflectance microscope system for viewing microscopic objects.
Just last March 16, 2007, another scientist from the National Institute of Physics in the University of the Philippines, Dr. Henry J. Ramos, was awarded a Taiwan patent for his invention entitled “Titanium Nitride Thin Formation on Metal Substrate by Chemical Vapor Deposition in a Magnetized Sheet Plasma Source.” The invention has a wide range of applications: cutting tools manufacturing, and the production of aerospace components, marine hardware, medical devices, and pharmaceutical equipment among others.

-By Jennalyn S. Baraquio and Agnes A. Paculdar

Breaking the frustration
The crystal structure of an oxide material is directly coupled to its ‘frustrated’ magnetic structure
Researchers from the RIKEN SPring-8 Center in Harima, the Japan Atomic Energy Agency and the universities of Tokyo and Virginia have discovered how changes to the crystal structure of the oxide material HgCr2O4 correlate to its magnetic state.
HgCr2O4 has an intriguing crystal structure where all relevant atoms are arranged in tetrahedra (Fig. 1 - Click on link below). When the interaction between the magnetic atoms at the corners of these tetrahedra is antiferromagnetic, a magnetic state with a zero net ‘moment’ is expected to occur—that is, there should be as many magnetic arrows pointing upwards as downwards. However, the geometry of the tetrahedra means that no perfectly homogeneous distribution of the moments is possible. This is known as ‘geometrically frustrated magnetism’.
To break the frustration, the system compensates for the uneven distribution of magnetic moments by distorting the crystal lattice (Fig. 1a). However, in response to an increasing external magnetic field, the magnetic moments realign and there is a stepwise reduction in crystal distortion (Fig. 1b). Once all magnetic moments are forced to point in the same direction, a perfectly symmetric crystal structure is assumed (Fig. 1c).
As reported in the journal Nature Physics (1), the research team studied the behavior of this material as they applied a slowly increasing magnetic field. They confirmed that the external magnetic field eventually breaks the zero magnetization of the sample and causes the magnetic spins to align along the external field—evidenced by sudden jumps in the sample magnetization followed by plateaus with constant magnetization.
Unlike other materials, HgCr2O4 is uniquely suited for this type of study, as these changes occur in magnetic fields small enough to be generated in experiments. Therefore, “the observation of magnetization plateaus in this compound over a wide range of magnetic fields is novel and a manifestation of the geometrical frustration,” explains Koichi Katsumata from the RIKEN team.
Importantly, the researchers studied for the first time the simultaneous evolution of the material’s crystal structure and found that as the magnetization jumps between the different plateaus, the crystal structure becomes less distorted (Fig. 1). Katsumata is therefore confident that this study “has unveiled the origin of some of the intriguing properties of geometrically frustrated magnets.” In particular, the results allow the validation and refinement of theoretical models describing the interaction between magnetism and crystal structure not only in this compound, but also in related systems.
Reference
1. Matsuda, M., Ueda, H., Kikkawa, A., Tanaka, Y., Katsumata, K., Narumi, Y., Inami, T., Ueda, Y. & Lee, S.-H. Spin-lattice instability to a fractional magnetization state in the spinel HgCr2O4. Nature Physics 3, 397–400 (2007).

Take your computer for a spin
RIKEN Large spin Hall effect measured at room temperature
RIKEN scientists have accurately measured a tiny voltage produced by segregating electrons according to their spin (1), a result which could help to usher in a new era of spin-based computing.
Conventional computers process and communicate information by shunting electrons around, but store data in the magnetic properties of tiny segments of a spinning disk drive. Yet that magnetism is also due to electrons—as each charged particle spins, it creates a magnetic moment. Electrons can spin ‘up’ or ‘down’, creating opposing poles like a bar magnet, and the burgeoning technology of spintronics uses these two states to represent bits of binary data. As well as storing information, these states can potentially be used to perform calculations.
The spin Hall effect (SHE) provides an important way to control these spinning electrons. The Hall effect itself (identified in 1879 by Edwin Hall) occurs when a magnetic field forces a current of electrons flowing through a flat plate to veer to one side. This causes charge to accumulate on that side of the plate, setting up a voltage across it. In a similar way, the SHE sends spin-up electrons to one side of the plate and spin-down to the other, setting up a ‘spin current’ (Fig. 1 - Click on link below).
Spin current is an important factor in operating future spintronic devices. Ferromagnets are normally used to differentiate spins, but interference between neighboring magnets makes it tricky to build working spintronic devices that way.
“However, if we use SHE, we can generate the spin current without using a ferromagnet,” says Takashi Kimura of RIKEN’s Frontier Research System, Wako. This could allow much easier integration of semiconductor and spintronic devices in the future.
Kimura and the team leader YoshiChika Otani have now found that the spin Hall conductivity—the potential for electrons to migrate due to the SHE—in a platinum wire is a thousand times greater than in previous experiments with semiconductor materials, making it easier to study and exploit the effect. Their electrical measurement technique is also more precise than the optical detection method usually employed.
It’s significant that the team has detected this effect at room temperature. It means that SHE is not only a physically interesting phenomenon, but also a useful way of manipulating spins in future spintronic devices, says Kimura.
The team is now trying to identify materials that produce even greater SHE conductivities. “We hope that new devices using SHE are proposed in near future,” says Kimura.
Reference
1. Kimura, T., Otani, Y., Sato, T., Takahashi, S. & Maekawa, S. Room-temperature reversible spin Hall effect. Physical Review Letters 98, 156601 (2007).

A concerted effort : proton transfer in a chemical reaction

Chemical reactions are processes in which one substance is transformed into another and involve the motion of atoms and electrons. Because these processes occur on short time-scales that are measured in femtoseconds (millionths of a billionth of a second), it is difficult to study what actually happens during a chemical reaction.
Of particular interest are reactions that involve the transfer of a hydrogen nucleus (a proton) between two molecules—an important process in biological systems. Tahei Tahara from RIKEN’s Discovery Research Institute in Wako has been studying proton transfer reactions for many years and views them as a challenge at the limits of science. “Because hydrogen is the lightest atomic species, it usually moves very quickly and is difficult to catch,” comments Tahara.
A model system in which proton transfer has been extensively studied is 7-azaindole. In solution, this compound exists in two different forms; discrete individual molecules (monomers), and pairs known as dimers. The dimers can be pushed into a higher energy ‘excited’ state by shining ultraviolet light on them, and subsequently undergo a double proton transfer reaction to form a structure known as a tautomer.
When Tahara published his first results on this system ten years ago, he says that, “the work triggered very intense world-wide debate.” The controversy stemmed from whether the two proton-transfer steps occurred sequentially in a step-wise reaction, or simultaneously in a ‘concerted’ process. Tahara has always argued that the concerted process is the correct one, a hypothesis that is further supported by his recent findings published in the Proceedings of the National Academy of Sciences of the USA (1).
By exciting the 7-azaindole dimer with different wavelengths of ultraviolet light and monitoring the fluorescence, Tahara and colleague, Satoshi Takeuchi, show conclusively that no intermediate structure is formed, thereby ruling out the possibility of a step-wise process. Significantly, their experiments demonstrate that a feature of the fluorescence decay that was attributed to a separate proton transfer actually corresponds to the conversion of the dimer from one excited state to another.
Because the 7-azaindole dimer is very similar in structure to the base pairs found in DNA, Tahara expects that this work may help to understand the chemical mechanism of how ultraviolet light affects DNA. In addition, Tahara and co-workers are now intending to observe nuclear motion in real-time using sub-10-femtosecond pulses of light, which he suggests, “may offer new opportunities for using light to control chemical reactions.”

Researchers find a gene controlling embryo orientation
Developmental biologists from RIKEN working with Japanese and Canadian colleagues have located an important gene that regulates the establishment of the head-to-tail or anterior-to-posterior (A–P) axis in mice. The future development of the whole embryo is orientated to this point of reference.
The A–P axis appears before the emergence of the three primary germ layers of body tissue during the process known as gastrulation, when the primitive ball of cells called the blastula folds in on itself to form the more complex, layered structure of the gastrula. Before gastrulation, there are only two types of tissue—epiblast from which the animal proper develops and visceral endoderm (VE) that forms all of the support structures such as blood vessels and nutrient cells.
The establishment of the A–P axis involves interplay between the VE cells and the underlying epiblast. In particular, a group of VE cells furthest from where embryonic structure attaches to the uterus migrates to close to where the head will develop in the epiblast. At the same time VE cells near the posterior end of the axis switch on a gene, Wnt, that produces a compound necessary to initiate gastrulation. In contrast, the VE cells at the head end or anterior visceral endoderm (AVE) produce compounds which block Wnt.
Earlier work has shown that the developmental gene known as Otx2 is critical in the generation and function of the AVE. In mutants lacking Otx2 there is no migration of VE cells to form the AVE and a key antagonist to Wnt is not produced. But the factors that regulated Otx2 were unknown.
In a recent paper in the Proceedings of the National Academy of Sciences (1), the researchers from RIKEN’s Center for Developmental Biology in Kobe and their colleagues describe how they used carefully engineered transgenic mice to demonstrate the critical role of the transcription factor Foxa2 in regulating Otx2. In laboratory studies, they also showed that the Foxa2 protein is needed for the production of at least two Wnt antagonists. Through these actions Foxa2 controls the establishment of the A–P axis.
Similar genes and compounds also exist in the pufferfish, fugu (Fig. 1 - Click on link). In fact, the group found, the fugu equivalent of Foxa2 can actually work in mice. According to the researchers, this shows how tightly the whole regulatory system has been conserved in the evolution of higher vertebrates from the bony fishes.
Reference

Playing tag highlights genetic disorder
A team of Japanese scientists led by Akimitsu Okamoto from the RIKEN Frontier Research System, Wako, has developed a new method for tagging a particular DNA base responsible for causing cancer.
Cytosine, a common DNA base, is reacted to add a methyl group to form methylcytosine during many biological processes. This process, known as methylation, is important for gene regulation, and DNA and protein stability. Further, excessive methylation of cytosine has been shown to result in cancer. The development of simple techniques to detect methylcytosine is therefore of great interest to scientists.
Although conventional methods have many advantages, they also have problems. Current methods cannot differentiate between cytosine and methylcytosine; they also destroy the DNA sample and are time-consuming. The latest technique by Okamoto and co-workers is selective for methylcytosine, fast and allows easy detection1.
The technique takes advantage of the easy oxidation of methylcytosine and uses three, specially designed, components to enable detection. When the reaction takes place, the methylcytosine forms a stable complex with an oxidant, potassium osmate, and a rate-enhancing ligand. The ligand, a bipyridine derivative, can then react further to bond with a variety of fluorescent or electrochemical tags allowing routine detection of the complex (Fig. 1 - Click on link below).
This conceptually new approach to methylcytosine detection takes just six hours to complete. Importantly, the key complex only forms between the methylcytosine and the ligand. This leaves the cytosine in the sample untouched and allows a clear distinction to be made. In addition, methylcytosines in single-stranded DNA efficiently formed the complex, whereas complexation of methylcytosines in a DNA duplex was suppressed. This result implies that the technique could also provide sequence-specific results giving detailed and accurate information of the methylated sites.
Okamoto explains that there is still more work to be done. Unfortunately, the information gained from the sequence-specific studies is limited as a consequence of the competing reaction with thymine, another DNA base. Also, the signal intensities and sensitivities are a little too weak to be useful on small sample sizes at this time.
Okamoto and his team are now striving to improve their technique so it can be used routinely in clinics with standard fluorescence or electronic signal analyzers. This technique is based on easy-to-use chemistry and Okamoto says, “Because the total process finishes in a few hours, this technique may make it possible to design machines that automate a series of processes from purification of samples to analysis.”
Reference

IMMUNOLOGY:Arresting autoimmunity
Working with a mouse version of multiple sclerosis, Gang Pei and colleagues study a protein called beta-arrestin 1, a factor known to regulate gene expression in all cells. Pei’s team reports that beta-arrestin 1 helps promote survival of T lymphocytes, which increases the duration of inflammation. In the absence of beta-arrestin 1 a critical factor required for T lymphocyte survival is not produced. Consistently, T lymphocytes lacking beta-arrestin 1 survive less well and cause much less brain inflammation in a mouse model of multiple sclerosis.
Demonstrating a role for beta-arrestin 1 in prolonging survival of aggressive T lymphocytes associated with autoimmune disease provides a possible target for reducing such diseases. Whether blocking the function of beta-arrestin 1 will help multiple sclerosis patients, however, remains a question for future investigation.
Author contact:
Gang Pei (Shanghai Institutes for Biological Sciences, China)
Tel: +86 21 5492 1371; E-mail: gpei@sibs.ac.cn

Growth factor reinforces cocaine addiction

Release of a growth factor in the nucleus accumbens – a brain area mediating reward – is necessary for the development and relapse of cocaine addiction.
Addictive drugs are thought to ‘hijack’ reward systems in the brain, causing neurons to be persistently more responsive to drug-associated cues and stressors. David Self and colleagues report that four hours after cocaine self-administration, rats show an increase in brain-derived neurotrophic factor (BDNF) in the nucleus accumbens. Preventing this increase in BDNF reduced cocaine self-administration and the propensity to relapse, whereas giving the rats daily BDNF injections after cocaine self-administration increased cocaine-seeking behaviour and relapse.
Moreover, using mice that were genetically engineered to lack BDNF only in the nucleus accumbens in adulthood, they showed that BDNF release in the nucleus accumbens did not affect the initial rewarding effects of cocaine, but did dramatically alter the development of addiction. If similar mechanisms mediate addiction in humans, these results could suggest possible approaches to addiction treatment.
Author contact:
David Self (University of Texas Southwestern Medical Center, Dallas, TX, USA)
Tel: +1 214 648 1237; E-mail: david.self@utsouthwestern.edu

Common genetic risk variant for colorectal cancer

A common variant on chromosome 8 that predisposes to prostate cancer also confers risk of colorectal cancer, according to three studies.Although a few relatively rare mutations have been identified that are associated with colorectal cancer, this is the first evidence for a common genetic risk factor. Colorectal cancer is one of the most commonly diagnosed forms of cancer.
In the first study, Richard Houlston, Ian Tomlinson and colleagues carried out a genome-wide association study for colorectal cancer and identified the most strongly associated variant on chromosome 8 as the same variant that had previously been associated with risk of prostate cancer. In the second study, Thomas Hudson, Malcolm Dunlop and colleagues screened a smaller number of variants across the genome but identified the same one on chromosome 8 as highly associated with colorectal cancer. Finally, Christopher Haiman and colleagues noted that the region on chromosome 8 that was shown to be associated with prostate cancer is also known to be amplified in individuals with colorectal cancer. Given this background they directly assessed the relevant variants in individuals with colorectal cancer and found them to be significantly more frequent than in cancer-free individuals. Haiman and colleagues also note that five other variants in this region that had been associated with prostate cancer were not associated with colorectal cancer, suggesting that the mechanism by which variants in the region contribute to cancer risk may differ depending on the type of cancer.
Author contacts:
Richard Houlston (Institute of Cancer Research, Sutton, UK)
Tel: +44 208 722 4175; E-mail: richard.houlston@icr.ac.uk

Ian Tomlinson (London Research Institute, Cancer Research UK)
Tel: +44 207 269 2884; E-mail: ian.tomlinson@cancer.org.uk Authors paper [7]

Thomas Hudson (The Ontario Institute for Cancer Research, Toronto, Ontario, Canada)
Tel: +1 416 673 6650; E-mail: tom.hudson@oicr.on.ca

Malcolm Dunlop (University of Edinburgh, UK)
Tel: +44 131 467 8439; E-mail: malcolm.dunlop@hgu.mrc.ac.uk Authors paper [8]

Christopher Haiman (University of Southern California, Los Angeles, CA, USA)
Tel: +1 323 865 0429; E-mail: haiman@usc.edu Author paper [9]

Nanocrystal shape control

The shape of metal nanocrystals can be accurately controlled by using a small particle of a different metal as a seed.
Peidong Yang and co-authors reacted a platinum nanocube (~13 nanometres each side) with a palladium-based compound to produce core–shell Pt/Pd nanocrystals. By varying the reaction environment, and in particular the amount of NO2, the researchers were able to obtain three different shapes — cubes, cuboctahedra and octahedra.
Many of the physical and chemical properties of nanocrystals depend strongly on their morphology. The authors show, for example, that the catalytic activity of the cubes is quite different from that of the other two types of nanocrystals. The use of seeds represents a clear step towards the development of nanocrystals with well-defined shapes.
Author contact:
Peidong Yang (University of California, Berkley, CA, USA)
Tel: +1 510 643 1545; E-mail: p_yang@berkeley.edu

new method to detect small changes in human genes
A new method to detect small changes in human genes could lead the way in personalized medicine. The most common type of variation in our genes is a single difference in one of the nucleotide building blocks of the DNA sequence, known as single nucleotide polymorphism (SNP—pronounced ‘snip’). Scientists believe differences in SNPs reveal an individual’s susceptibility to disease, meaning accurate analysis of SNPs would play a key role in diagnostics. These small SNP variations can account for as little as 0.1 per cent of a genome sequence.
SNP diagnostics have recently attracted much attention and several strategies to identify SNPs have been developed in the past few years. Existing methods are often limited by the need to identify large DNA sequences. Now, a team of Japanese researchers led by Akimitsu Okamoto from the RIKEN Frontier Research System, Wako, has used derivatives of the fluorescent dye PRODAN to correctly identify SNPs quickly and efficiently1.
PRODAN, a well-known fluorophore, absorbs and emits light at different wavelengths depending on the polarity of its environment. Okamoto reasoned that similar dyes, which include differing nucleotide components, could be incorporated into DNA structures and ‘report back’ differences in the microenvironment. Such changes in the microenvironment would likely be the result of small changes in the DNA structure and allow detection of sequence variations (Fig. 1 - Click on link below). The team synthesized four variants of the dye, so that all combinations of base matches and mismatches could be investigated.
Once incorporated in a DNA sequence under a variety of conditions, the team calculated the differences between the wavelengths absorbed and emitted by the dye. These differences are known as Stokes shifts. The researchers detected a small Stokes shift when DNA base pairs matched correctly, but a larger shift when there was a mismatch. Therefore, by using various PRODAN-labeled DNA dyes, single nucleotide alterations could be detected. “The use of this DNA probe makes it possible to judge the type of base located at a specific site on the target DNA, simply by mixing the DNA and the dye together. This method is a very powerful assay that does not require enzymes or time-consuming steps, and avoids errors,” says Okamoto.
Okamoto believes that this method of detection is very promising and is working towards making the system suitable for every day use. “I think SNP chips using our probe would make important contributions to cancer diagnosis,” he enthuses.

Origin of adult blood cells clarified
A research team at the RIKEN Center for Developmental Biology, Kobe, has developed a cell tracing method that unambiguously identifies the yolk sac—an extra-embryonic structure—as a source of blood cells in both the embryo and, later, the adult.
Developmental biologists have debated the original source blood cells in adult mammals for over thirty years. Now, a team led by Igor Samokhvalov at the RIKEN Center for Developmental Biology, Kobe, has developed a cell tracing method that unambiguously identifies the yolk sac—an extra-embryonic structure—as a source of blood cells in both the embryo and, later, the adult.
The yolk sac, which provides the developing embryo with nutrients, is the first extra-embryonic structure to form during embryogenesis. This structure is also the first place of embryonic blood cell formation (hematopoiesis). A central question in developmental biology about hematopoiesis is the role—if any—the yolk sac-derived blood cells play in the development of adult blood cells.
“The origin of [the] hematopoietic [blood] system was always obscure and controversial; this was the reason I became interested in this area of hematology,” says Samokhvalov.
To resolve the controversy, the team labored for two years to develop a cell tracing method to follow yolk sac-derived blood cells through later stages of embryonic development1. The ability to study this development non-invasively through time was critical, says Samokhvalov, because removing cells from tissue introduces stresses that can lead to an inaccurate picture of actual embryonic processes.
The method consists of replacing of one copy of a gene called Runx1, which is essential for blood development, with another gene that produces a protein creating ‘tags’ in the cells and all their progeny. The ‘new’ gene is turned on at the same time Runx1 normally is—at a mere 7.5 days after embryonic development begins.
Tagging the earliest Runx1-expressing yolk sac cells at day 7.5 of development allowed the team to follow these cells’ progeny when they’re incorporated into blood vessel walls (Fig. 1 - Click on link below), and evaluate their long-term contribution to the adult blood system.
So clear were the results, remarks Samokhvalov, that “our work showed direct contribution of [the] yolk sac to adult haematopoiesis”. Indeed, the team’s direct and carefully designed cell tracing methodology eliminated ambiguities that could lead to alternative interpretations.
This work settles the long-standing controversy, marking an important step forward in developmental biology. However, the team’s data do not rule out the possibility of an additional source of haematopoietic stem cells in the embryo.
Samokhvalov’s future plans include determining more precisely the extent of the yolk sac’s participation in adult blood development, and whether another source of haematopoietic stem cells occurs in the embryo itself.

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.