Volume 464 Issue 7288, 25 March 2010

Lack of US regulation is allowing dubious dietary supplements to be sold as life-enhancing elixirs.

Nature's new online commenting facility opens up the entire magazine for discussion.

The week in science.

DNA analysis reveals lost relative from 40,000 years ago.

Samples could reveal unique life forms from beneath the ice.

Facing a flood of applications from researchers, a UK funding agency is taking drastic steps — and partners around the world are watching how it plays out. Richard Van Noorden and Geoff Brumfiel report.

Expanded programme of academic collaboration promised.

Research involving transgenic organisms may be strangled by red tape.

Translational work set to receive a boost.

Questions about a laboratory assay are making Sirtris, a high-profile biotechnology company, the talking point of the ageing field. Heidi Ledford investigates.

Social scientists have embedded themselves at CERN to study the world's biggest research collaboration. Zeeya Merali reports on a 10,000-person physics project.

To capture the essence of good science, stakeholders must combine forces to create an open, sound and consistent system for measuring all the activities that make up academic productivity, says Julia Lane.

Emotions such as empathy and disgust might be at the root of morality, but psychologists should also study the roles of deliberation and debate in how our opinions shift over time, argues Paul Bloom.

From caloric restriction to red-grape skins, the anti-ageing industry goes beyond scientific results to market treatments to those who hope to cheat death, cautions S. Jay Olshansky.

Theoretical analyses reveal how plant investment in the architecture of leaf veins can be shuffled for different conditions, minimizing the construction costs associated with supplying water to leaves.

Colloid particles that form bonds to each other at specific orientations might self-assemble into all sorts of useful materials. The key — and the lock — to such binding has been discovered.

Ever since Leonardo da Vinci sketched the heart vessels in his anatomical notebook in the late fifteenth century, the origin of the coronary vasculature has been in question. We might just have come upon the answer.

The flux of carbon from soils to the atmosphere has apparently increased with climate warming. But does this reflect a net loss of carbon to the atmosphere that could exacerbate climate change?

Microorganisms that grow by oxidizing methane come in two basic types, aerobic and anaerobic. Now we have something in between that generates its own supply of molecular oxygen by metabolizing nitric oxide.

Builder of the world's largest radar/radio telescope.

In certain microbes, the anaerobic oxidation of methane can be linked to the reduction of nitrates and nitrites. Here it is shown that this occurs through the intermediate production of oxygen. This brings the number of known biological pathways for oxygen production to four, with implications for our understanding of life on the early Earth.

Prevailing models propose that coronary arteries in the developing heart are formed from progenitor cells originating in the proepicardium. It is found here, however, that these arteries arise from angiogenic sprouts of the major vein that returns circulating blood to the embryonic heart. Thus some differentiated venous cells retain developmental plasticity and respond to local signals to convert to coronary arteries, capillaries and veins.

In the mammalian brain, the subventricular zone (SVZ) produces neural progenitor cells that migrate into the cortex to populate the upper layers. In humans this region is massively expanded, producing an outer SVZ (OSVZ). Here, live-cell imaging of developing human tissue was used to show that the OSVZ has similar characteristics to the SVZ, with progenitor cells proliferating in a way that depends on the Notch protein. The findings have implications for our understanding of how the complex human brain evolved.

The main observational signature of star-forming galaxies at the highest redshifts is the Lyman-α (Lyα) emission line. But Lyα photons scatter in the neutral interstellar medium of their host galaxies, and may therefore be greatly absorbed by interstellar dust. It is now shown that the average escaping fraction of Lyα photons from star-forming galaxies at redshift z = 2.2 is just 5 per cent. This implies that numerous conclusions based on Lyα-selected samples will require upwards revision by an order of magnitude.

A two-dimensional gas of electrons is a powerful test-bed for the fundamental physics of interacting particles, and has been much studied in the context of integer and fractional quantum Hall effects. The latest observations of this system reveal prominent structure in the high energy single particle spectrum that cannot be readily explained with existing models of this system.

An imaging technique that could identify all the individual atoms, including defects, in a material would be a useful tool. Here an electron-microscopy approach to the problem, based on annular dark-field imaging, is described. A monolayer of boron nitride was studied, and three types of atomic substitution were identified. Careful analysis of the data enabled the construction of a detailed map of the atomic structure.

Many functional materials can be created by directing the assembly of colloidal particles into a desired structure. Control over particle assembly usually involves the use of molecules such as DNA that can recognize and bind each other. Here, a simple and effective alternative is described. Colloidal spheres serve as keys, and monodisperse colloidal particles with a spherical cavity as locks. These will spontaneously and reversibly bind to each other via the depletion interaction if their sizes match.

Soil respiration (R_S) is the flux of microbial- and plant-respired carbon dioxide from the soil surface to the atmosphere, and constitutes the second-largest terrestrial carbon flux. It has been suggested that R_S should change with climate, but this has been difficult to confirm observationally. It is shown here, however, that the air temperature anomaly (the deviation from the 1961–1990 mean) correlates significantly and positively with changes in R_S.

Genotype and phenotype cannot be connected simply by one-to-one mapping; instead they are linked by the nonlinear process of development. Here, a computational model is described — based on real data about the development of seal teeth — that attempts to combine the three. The results show that a few genetic parameters regulating signalling during cusp development may explain variation among individuals. But a cellular parameter regulating epithelial growth may explain tooth-to-tooth variation along the jaw.

Here, the genomes of birds representing eight populations of domestic chickens are compared with the genome of their wild ancestor, the red jungle fowl. The results reveal selective sweeps of favourable alleles and mutations that may have contributed to domestication. One selective sweep, for instance, occurred at the locus encoding the thyroid stimulating hormone receptor, which is important in metabolism and in the timing of vertebrate reproduction.

The freshwater cnidarian Hydra is a significant model for studies of axial patterning, stem cell biology and regeneration. Its (A+T)-rich genome has now been sequenced. Comparison of this genome with those of other animals provides insights into the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, pluripotency genes and more.

Reactive electrophiles are noxious chemicals, such as acrolein in cigarette smoke, and are detected by the ion channel TRPA1 in humans. Here it is shown that TRPA1 channels sense these chemicals in the gustatory chemosensory neurons of fruitflies and mosquitoes, too. Further findings show that, unlike with other chemical senses such as smell or taste, the detection of reactive electrophiles relies on an ancient sensor that has been conserved in molecular detail through some 500 million years of evolution.

Zebrafish are able to replace lost heart muscle efficiently, and are used as a model to understand why natural heart regeneration — after a heart attack, for instance — is blocked in mammals. Here, and in an accompanying paper, genetic fate-mapping approaches reveal which cell population contributes prominently to cardiac muscle regeneration after an injury approximating myocardial infarction. The results show that cardiac muscle regenerates through activation and expansion of existing cardiomyocytes, without involving a stem-cell population.

Zebrafish are able to replace lost heart muscle efficiently, and are used as a model to understand why natural heart regeneration — after a heart attack, for instance — is blocked in mammals. Here, and in an accompanying paper, genetic fate-mapping approaches reveal which cell population contributes prominently to cardiac muscle regeneration after an injury approximating myocardial infarction. The results show that cardiac muscle regenerates through activation and expansion of existing cardiomyocytes, without involving a stem-cell population.

Each human cell contains hundreds of copies of mitochondrial DNA (mtDNA), making it difficult to characterize mtDNA completely. Here, massively parallel sequencing-by-synthesis of mtDNA reveals widespread heterogeneity (heteroplasmy) in the mtDNA of normal human cells, and homoplasmic and heteroplasmic mutations in cancer cells. The findings provide new insight into the nature and variability of mtDNA sequences, with implications for forensic analysis and the development of biomarkers for cancer.

Making haploid plants — which inherit chromosomes from only one parent — is useful for genetic research and also, crucially, for plant breeding. A new method for generating haploid Arabidopsis plants is now described, involving the manipulation of a single centromeric protein, CENH3. When cenh3 null plants are crossed with wild-type plants, the mutant chromosomes are eliminated, producing haploid progeny.

An understanding of how fat cells (adipocytes) develop will contribute to our understanding of obesity. The differentiation of committed preadipocytes into adipocytes is known to be controlled by PPARγ and several other transcription factors. But what turns a cell into a preadipocyte? Here, the zinc-finger protein Zfp423 is identified as a transcriptional regulator of preadipocyte determination.

In response to oncogenic stress, the tumour suppressor ARF activates the p53 protein. ARF protein is highly stable in most human cell lines, so it has been thought that ARF activation occurs mainly at the level of transcription. Here, however, ARF is shown to be unstable in normal human cells but stable in cancer cells, through a transcription-independent mechanism. A ubiquitin ligase for ARF is identified and shown to promote ARF degradation in normal cells. This activity is prevented in cancer cells, stabilizing ARF.

Female gametes in flowering plants develop from a meiotic division of a precursor cell followed by mitotic divisions of one of the resulting haploid cells to yield the gametophyte. Here, ARGONAUTE 9 (AGO9) — a protein involved in RNA interference — is identified as a factor required for specification of the gametophyte. AGO9 is found not in the cell destined to be the gametophyte, but in the neighbouring companion cells, suggesting that it functions in a non-cell-autonomous manner.

Cheng-An Lin, a biomedical engineer at Chung Yuan Christian University (CYCU) in Taiwan, received the 2010 Young Investigator Award from the International Society for Optical Engineering (SPIE) on 25 January.

US budget deficit could jeopardize salary increase.

Initiative to boost student interest in science may explain increase.

Canadian postdoc association protests over government plans.

According to some metrics, Indiana's life-sciences sector is among the nation's top performers. But there are financial and other challenges. Karen Kaplan maps out the possibilities.

Deep thoughts.

Worldwide, the number of old people is increasing rapidly, so finding ways to keep age-related diseases at bay is an urgent task. Owing to a growing understanding of the processes that underlie ageing, there is hope that, at some time in the future, elderly people will be kept healthy by suppressing the ageing process itself.