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Nature Press Release for 21 August Issue
PLEASE CITE NATURE AND OUR WEBSITE www.nature.com/nature AS THE SOURCE OF THE FOLLOWING ITEMS. IF PUBLISHING ONLINE, PLEASE CARRY A HYPERLINK TO http://www.nature.com/nature [1] Health and Medicine: Anti-malarials explained (pp957-961; N&V) A molecular target for the class of anti-malaria drugs called artemisinins has been identified, researchers report in this week's Nature. Artemisinins have become increasingly important for treating malaria as resistance to existing drugs spreads. In some parts of southeast Asia they are the only effective anti-malarial. They were discovered in the 1970s — extracted from the Chinese herb quingao or sweet wormwood (Artemisia annua), a long-recognised anti-malarial remedy. Their mode of action however, remained obscure. The leading theory was that artemisinins interact with haem molecules, a breakdown product of the malaria parasite's human red-blood-cell meal. The interaction was thought to release massive quantities of free radicals — enough to kill the parasite. Not so, find Sanjeev Krishna and colleagues. They show that artemesinins block the action of a metabolic enzyme called PfATP6 that is crucial to the life of the parasite. The finding could eventually lead to the manufacture of synthetic artemisinins with greater preference for PfATP6. In the short-term, studying the genetics of PfATP6 in populations of wild parasites could help to pre-empt resistance that has rendered other drugs useless, the researchers claim. Krishna's work "has a practical significance beyond its undoubted scientific merit," comments Robert Ridley in an accompanying News and Views article.
[2] Marine Biology: The fibre-optic sea sponge (pp899-900) A deep-sea sponge has fibre-optic-like outgrowths that surpass any used in the telecommunications industry, according to a Brief Communication in this week's Nature. The skeleton of the deep-sea 'glass' sponge Euplectella is made from an intricate silica cage that typically houses a mating pair of shrimp — hence its nickname, 'Venus' flower-basket' — and is composed of a lattice of fused outgrowths or 'spicules', which provide structural support. Joanna Aizenberg and colleagues have looked at the optical properties of the tri-layered spicules. They are similar in size to, and made from the same material as, conventional fibre-optic cables. The layers also have a similar gradation in their refractive indices, indicating that they bend light in a similar manner. Man-made fibre-optic cables often crack and break, whereas Euplectella's spicule layers are connected in a way that enhances their toughness and makes them less likely to fracture. "This illuminating sponge should also shed light on low-temperature, biologically inspired processes that could give rise to better fibre-optical materials and networks," the team says. [3] Development: RNA can regulate plant development ***This paper will be published electronically on Nature's website on 20 August at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 21 August, but at a later date.*** Tiny pieces of RNA affect gene expression and leaf shape in thale cress (Arabidopsis), according to a report published online by Nature this week. A new study shows how, under normal circumstances, short RNA strands called microRNAs can help control development — the first time this has been demonstrated in plants. MicroRNAs can bind to messenger RNA — the intermediary between DNA and proteins — and inactivate genes. Detlef Weigel and colleagues found high levels of one such microRNA in a mutant Arabidopsis plant with unusual serrated leaves. In this case, the microRNA restrains the production of a protein called TCP4, they report. When it was altered so that it could no longer bind to its TCP-related target, leaf shape was changed again. This proves that the microRNA levels are controlling the gross shape of plant leaves. MicroRNAs have been found in all complex, multicellular organisms examined. Like their DNA-based cousins, it is becoming clear that these small nucleic acid strands provide an intricate control network for developmental processes. [4] Earth: Deep earthquakes trigger more of the same (pp921-925; N&V) Earthquakes that take place deep underground may trigger additional, distant, deep quakes, a study in this week's Nature suggests. A recent example may shed light on how these events are generated. Earthquakes commonly occur in our planet's crust, but they also take place further down, at depths of up to 700 kilometres. Near-surface quakes can trigger more of the same, but it was not thought that deep earthquakes have a similar knock-on effect. Rigobert Tibi and colleagues have analysed several large, deep earthquakes that occurred on 19 August 2002 beneath the southwestern Pacific Ocean, near Tonga. Although two of the largest quakes were separated by 300 kilometres, they occurred within minutes of each other and the authors argue that the second earthquake was triggered by seismic waves generated from the first. These findings are a "major advance in understanding deep earthquakes, and they might provide a new constraint on the mechanism by which these earthquakes begin," says Harry W. Green in an accompanying News and Views article. [5] Ecology and Evolution: Bird song prompts species split (pp928-931) The love of a familiar tune has prompted the evolution of ten new species of indigobird, according to a study in this week's Nature. African indigobirds (Vidua spp.) lay their eggs among those of other species. A male, adult indigobird learns the songs of his firefinch hosts and uses them in his own courtship. A female, in turn, will only mate with males that sing the host melodies she learned as a youngster. Now, Michael D. Sorenson and colleagues have studied the genetic make-up of a range of indigobirds. They report that song recognition prompted the development of ten distinct indigobird species from a recent common ancestor. Single species classically diverge as individuals become geographically isolated. Here, the indigobird uses firefinch song as a kind of identification system. The different tunes effectively isolate populations of indigobirds, much like a geographical barrier. [6] Chemistry: Chemists create enzyme-mimicking catalyst (pp915-918) A catalyst that mimics the features of a class of enzymes is described in this week’s Nature. Its designers were motivated by natural enzymes that latch on to DNA strands and move along their length in a stepwise fashion, carrying out several rounds of catalysis before detaching. Like its inspiration, the catalyst created by Alan E. Rowan and colleagues is essentially a large and bulky ring that attaches to and surrounds its polymer substrate. The ring’s interior — picture the edge of the hole in a doughnut — is lined at one site with a metal complex that initiates an oxidation reaction. As the catalyst remains bound and moves along the polymer chain — like a doughnut travelling along a rope threaded through its centre — it oxidizes repeating double bonds in the polymer. A large molecule tagged to the outside of the catalyst both activates and shields it, restricting the reaction to inside the ring. Although it’s unclear whether the catalyst proceeds smoothly across the polymer or jumps along to initiate catalysis in a random fashion, the results show that it is possible to make relatively controlled changes to a polymer after it has been made, using a catalyst that mimics DNA-modifying enzyme systems. [7] and [8] Ecology and Evolution: Key genes prompt species to converge (pp931-935, 935-938; N&V) A small number of genes may prompt different species to evolve similar characteristics, according to two papers in this week's Nature. This research suggests that just a few developmental changes may cause separate species to converge. David L. Stern and colleagues studied hair development in different species of Drosophila fly larvae. They found that three of the lineages had independently evolved bald patches, and that a gene called shavenbaby was absent in these regions. The team suggest that the loss of this one gene was enough to prompt the evolution of hair loss in different fly species. Nicolas Gompel and Sean B. Carroll also looked at fruit flies, but, this time, they studied how abdominal pigmentation varied across different species. The duo discovered that the products of two bric-a-brac genes, bab1 and bab2, are responsible for abdominal patterning and hair development. Across species, changes in pigmentation and hair formation were sometimes, but not always, linked. "Gompel and Carroll suggest that the two traits become uncoupled when they are under different selective pressures," say Michael K. Richardson and Paul M. Brakefield in an accompanying News and Views article. "Each gene might represent a developmental 'hotspot' for evolution," they add. [9] Linguistics: Low-status languages face extinction (p900) Low-status languages may disappear more quickly than their more highly rated competitors, a Brief Communication in this week's Nature suggests. Action is needed to prevent the rapid disintegration of our world's linguistic heritage. Daniel M. Abrams and Steven H. Strogatz have developed a simple model of language competition to explain how dialects like Welsh, Scottish Gaelic and Quechua — the most common surviving indigenous language in the Americas — have declined in usage over time. They collected data on the number of speakers of endangered languages in 42 regions around the world. From their model, they suggest that a language's status may predict its extinction threat. Quechua, for example, still has many speakers in Huanuco, Peru, but its low status is driving a rapid shift to Spanish — it is not uncommon for a child to be unable to communicate with its grandparents, for example. 90% of languages are expected to disappear within our current generation. Strategies are needed to slow language decline, the team urge. Policy-making, education and advertising have already made a difference to the status of Quebec French. Similar measures may make a difference elsewhere, the authors hope. [10] And Finally… What's in a name? (pp925-928; N&V) Imagine being classified as a bag of chips, just because that's the last thing that you ate. Sounds unlikely, but a similar mislabelling befell the unfortunate marine worm Xenoturbella, according to a paper in this week's Nature. Its problem lies in its lack of defining features — it has no proper gonads, excretory system or body cavity. In 1997, DNA tests suggested that Xenoturbella was, in fact, a bivalve mollusc. The discovery of internal mollusc-like eggs seemed only to confirm the finding. Now, Maximilian J. Telford and colleagues propose an alternative theory. Mollusc-like DNA and eggs are present because Xenoturbella fed on molluscs, not because it was a mollusc. The team managed to analyse a small residue of genuine Xenoturbella DNA. "The results are even more surprising than the supposed parentage of Eliza Doolittle," says Henry Gee in an accompanying News and Views article. "Xenoturbella is no ordinary flower-girl, but arguably the most primitive extant member of the deuterostomes…the great group of animals to which we ourselves belong." Henry Gee (Senior Editor, Nature) is currently on holiday ALSO IN THIS ISSUE… [11] The role of stomata in sensing and driving environmental change (pp901-908) [12] Observing brownian motion in vibration-fluidized granular matter (pp909-912; N&V) [13] Signature of optimal doping in Hall-effect measurements on a high-temperature superconductor (pp912-915) [14] Extreme deuterium enrichment in stratospheric hydrogen and the global atmospheric budget of H2 (pp918-921) [15] Trans-synaptic shift in anion gradient in spinal lamina I neurons as a mechanism of neuropathic pain (pp938-942) [16] Different domains of synaptotagmin control the choice between kiss-and-run and full fusion (pp943-947) [17] Generation of prion transmission barriers by mutational control of amyloid conformations (pp948-952) [18] BAD and glucokinase reside in a mitochondrial complex that integrates glycolysis and apoptosis (pp952-956; N&V) [19] Feedback regulation of MAPK signalling by an RNA-binding protein (pp961-965) [20] Transcription factor IIB cetylatesitself to regulate transcription (pp965-969) [21] Complex between nidogen and laminin fragments reveals a paradigmatic b-propeller interface (pp969-974) GEOGRAPHICAL LISTING OF AUTHORS… The following list of places refers to the whereabouts of authors on the papers numbered in this release. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details. CANADA DENMARK FRANCE GERMANY ITALY JAPAN THE NETHERLANDS THE PHILLIPINES PORTUGAL SWITZERLAND UNITED KINGDOM UNITED STATES OF AMERICA Nature Publishing Group is a division of Macmillan Publishers Ltd. Macmillan is an international publisher serving the information and education community as well as publishing fiction and non-fiction.
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