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This press release is copyright Nature. VOL.440 NO.7086 DATED 13 April 2006
This press release contains:
Palaeontology: Fossil finds bolster our ancient African ancestry
Malaria: Bio-engineering could fuel antimalarial drug production
Genetics: A matter of taste
Environment: Limited nitrogen curbs plants’ ability to suck up carbon
Photonics: White light, no heat
Microbiology: Triggering insulin resistance
Neuroscience: Watching synpases at work
Microbial ecology: The ‘impossible’ microbes
Animal behaviour: Doting mums let their kids eat them
Quantum physics: The gas that won't settle down
Astronomy: A new spin on Vega
And finally… Catfish hunts on land
Mention of papers to be published at the same time with the same embargo
Geographical listing of authors
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[1] Palaeontology: Fossil finds bolster our ancient African ancestry (pp883-889)
Palaeontologists toiling in the cradle of humanity, Ethiopia, have discovered a cache of fossils that represent another part of our evolutionary story. The 4.2-million-year-old fossils consist of remains of Australopithecus anamensis, thought to be a direct ancestor of modern humans.
The new fossils support the theory that Au. anamensis was a direct ancestor of Au. afarensis, the species that included the famous fossil skeleton known as Lucy. The Australopithecus genus is thought to have subsequently given rise to our own genus, Homo.
The new specimens, which include the largest hominid canine ever found and the earliest known Australopithecus thigh bone, extend the range of Au. anamensis in Ethiopia, say Tim White and colleagues, who unveil the findings in this week's Nature. The discovery was made in the Middle Awash region of the country, around 1,000 kilometres north of Kenya's Turkana basin, the resting place of previously unearthed remains of the species.
CONTACT
Tim White (University of California, Berkeley, CA, USA)
Tel: +1 510 642 2889; E-mail: [email protected] <mailto:[email protected]>
[2] Malaria: Bio-engineering could fuel antimalarial drug production (pp940-943)
Chemical and biomedical engineers have created a strain of yeast that is able to manufacture a chemical precursor of the antimalarial drug artemisinin, an advance that could be used to generate large amounts of this potent drug efficiently and cheaply.
Malaria kills more than one million people annually, and artemisinin is the drug of choice for treating those infected with multi-drug resistant strains of the parasite. It is currently extracted from Artemisia annua (commonly known as sweet wormwood), but supplies are limited and the drug is expensive, meaning that it is currently not possible to treat many malaria sufferers in the developing world.
In this week’s Nature, Jay Keasling and his colleagues present a possible way around this problem. By tweaking existing biosynthetic pathways in the yeast Saccharomyces cerevisiae, and inserting two genes from A. annua, they created yeast capable of churning out large quantities of artemisinic acid, a precursor of artemisinin. Other researchers have shown that this precursor can be converted into artemisinin in a handful of chemical steps, so the authors hope that - once the process is optimized and scaled-up - their findings could reduce the cost of artemisinin synthesis and help save lives.
CONTACT
Jay Keasling (University of California, Berkeley, CA, USA)
Tel: +1 510 495 2620; E-mail: [email protected] <mailto:[email protected]>
[3] Genetics: A matter of taste (pp930-934)
An identical variability in taste sensitivity evolved independently in chimpanzees and humans according to research in this week's Nature. The two species share variability in their taste sensitivity to a bitter compound known as phenylthiocarbamide (PTC). This research contradicts a previous report in Nature 65 years ago, which suggested natural selection was responsible for 'taster' and non-‘taster’ individuals in each species.
Sensitivity to bitter taste is crucial for identifying the presence of toxic compounds, allowing animals to exploit and monitor their consumption of toxic foods. In humans and chimpanzees, individuals either recognize PTC as a bitter taste, or cannot taste it at all. Armed with the knowledge of the gene responsible for PTC sensitivity, Wooding and colleagues now revisit the original comparative experiment. They find that the mutation responsible for the polymorphism of the gene in chimpanzees is different to that in humans, demonstrating that the genetic code for non-‘taster’ individuals has evolved at least twice in hominids.
The authors suggest the characterization of such patterns could have important implications for nutrition and health.
CONTACT
Stephen Wooding (University of Utah, Salt Lake City, UT, USA)
Tel: +1 801 585 7423; E-mail: [email protected] <mailto:[email protected]>
[4] Environment: Limited nitrogen curbs plants’ ability to suck up carbon (pp922-925)
The limited amount of nitrogen in the world’s soils could constrain the extent to which plants can mop up rising carbon dioxide (CO2) levels and temper global warming, according to a study in this week’s Nature.
Plants are expected to offset some of the rise in global CO2 levels by using the gas to fuel new growth - but it has been a matter of some debate whether a lack of nitrogen, which is also vital for plant growth, could limit this process.
In one of the longest-running studies to tackle this question, Peter Reich and his colleagues show that the stimulation in growth of several grassland species induced by experimentally elevated CO2 becomes restricted at normal levels of soil nitrogen after four to six years - but the plants grow faster when grown in nitrogen-enriched soil. The authors say that it will be important to understand the variability in nitrogen availability worldwide in order to accurately estimate the role of vegetation as a future carbon sink.
CONTACT
Peter Reich (University of Minnesota, St. Paul, MN, USA)
Tel: +1 612 624 4270; E-mail: [email protected] <mailto:[email protected]>
[5] Photonics: White light, no heat (pp908-912)
Light-emitting diodes (LEDs) made from carbon-based molecules could become extremely economical white-light sources, and the most efficient of these devices now makes its debut in this week's Nature.
Stephen Forrest and colleagues say that their white-light, organic LED is already 50-75% more efficient than conventional light bulbs of similar brightness.
Lighting accounts for about 22% of the electricity consumed in buildings in the US, and 40% of that amount is eaten up by inefficient incandescent bulbs.
The team's device makes use of both phosphorescent and fluorescent molecules, arranged in such a way to optimize the conversion of electricity to light. The combination of green and red phosphorescent compounds with a blue fluorescent molecule produces a stable colour balance.
CONTACT
Stephen Forrest (University of Michigan, Ann Arbor, MI, USA)
Tel: +1 734 647 1147; E-mail: [email protected] <mailto:[email protected]>
[6] Microbiology: Triggering insulin resistance (pp944-948)
A study in this week’s Nature identifies reactive oxygen species as key players in the development of insulin resistance. Insulin resistance is a hallmark of type 2 diabetes, but can also occur in clinical settings such as pregnancy and obesity.
As their name suggests, reactive oxygen species are highly reactive forms of oxygen that are by-products of cellular respiration and metabolic activity. They have 'Jekyll and Hyde' characteristics, acting as useful signalling molecules but also damaging cells by causing oxidative stress.
Eric Lander and colleagues set out to test the link between reactive oxygen species and insulin resistance, as it is known that many patients with insulin resistance also suffer from oxidative stress. The authors exposed fat-storage cells to two chemicals that induce insulin resistance, and found that levels of reactive oxygen species increased in both of these models. They then treated the cells with agents to suppress the production of reactive oxygen species, which in turn reduced insulin resistance. They repeated this experiment in vivo in obese mice, finding the same results.
The authors highlight the need for further studies to strengthen the relationship between reactive oxygen species and insulin resistance, but suggest that antioxidant therapy could prove a promising strategy for treating conditions such as type 2 diabetes.
CONTACT
Eric Lander (Broad Institute of MIT and Harvard, Cambridge, MA, USA)
Tel: +1 617 252 1906; E-mail: [email protected] <mailto:[email protected]>
[7] Neuroscience: Watching synpases at work (pp935-939; N&V)
In this week's Nature, scientists have used clever microscopy to address fundamental questions about the workings of synapses, the junctions between neurons.
Neuroscientists know that vesicles - small, membrane-wrapped packages of chemical neurotransmitters - are released at the synapse, and that vesicle membranes are then incorporated back into the main cell membrane. The details of this process have been elusive because the vesicles are so small (about 40 nanometres across) that they cannot be resolved using conventional fluorescence microscopy.
Reinhard Jahn and his colleagues have adopted a remarkable new technique called stimulated emission depletion (STED), which effectively restricts fluorescence to a very small spot on a sample, producing much sharper microscope images. By studying cultured neurons, the team has shown that some components of the vesicle membrane stay together during recycling. The authors say that this technique could also be used to view other, even smaller cellular structures.
CONTACT
Reinhard Jahn (Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany)
Tel: +49 551 201 1634; E-mail: [email protected] <mailto:[email protected]>
Garth Simpson (Purdue University, West Lafayette, IN, USA)
Tel: +1 765 496 3054; E-mail: [email protected] <mailto:[email protected]>
[8] Microbial ecology: The ‘impossible’ microbes (pp918-921; N&V)
Ecologists have discovered, in a Dutch canal, a tag team of two microbial species that, together, are living what biologists had thought was an impossible existence. The duo, consisting of a bacterium and a member of the kingdom Archaea, oxidize methane in the absence of oxygen - a feat they pull off by breaking down nitrates, a main component of agricultural runoff.
Researchers led by Marc Strous stumbled upon the cosy arrangement in an oxygen-depleted waterway called the Twentekanaal in The Netherlands. There was no thermodynamical reason why this metabolic lifestyle had been previously ruled out - it’s just that no one had ever seen it in action before.
The two microbes both belong to as-yet-unnamed species and had not been cultured in the laboratory before this study. But the existence of similar organisms in oxygen-deprived freshwater around the world suggests that this lifestyle may contribute much to the global cycling of nitrates that run off from fertilized farmlands.
CONTACT
Marc Strous (Radboud University Nijmegen, Nijmegen, Netherlands)
Tel: +31 243 652 657; E-mail: [email protected] <mailto:[email protected]>
Rudolf Thauer (Laboratorium für Mikrobiologie der Philipps-Universität, Marburg, Germany)
Tel: +49 6421 178200/201; E-mail: [email protected] <mailto:[email protected]>
[9] Animal behaviour: Doting mums let their kids eat them (pp926-929)
Do you love your kids enough to let them eat your very flesh? Boulengerula taitanus does: brooding mothers of this wormlike amphibian, part of a group called the caecilians, give their offspring the best possible start in life by transforming their own skin into a nourishing meal that the youngsters can eat.
Researchers led by Mark Wilkinson spotted the young of this species, which lives in Kenya, grazing their mother's hide with specialized teeth. As the authors report in Nature, the doting new parent transforms her outer layer of skin into a nutritious fat-rich offering, not dissimilar in its nutrient content to milk.
The specialization is a never-before-seen strategy for feeding young, Wilkinson's team adds. Young of B. taitanus hatch from eggs, but the practice of feeding on the mother's skin may represent a key intermediate stage on the way to live birth, which would require the developing young to pull off the same trick, but from the inside out.
CONTACT
Mark Wilkinson (The Natural History Museum, London, UK)
Tel: +44 20 7942 5164; E-mail: [email protected] <mailto:[email protected]>
[10] Quantum physics: The gas that won't settle down (pp900-903; N&V)
In a box there are two gases separated by a partition. Now remove the partition, and the gases will eventually become perfectly mixed. That seems obvious, and indeed it would be bizarre if the two gases, instead of mixing, just kept swapping places in one half of the box or the other.
But David Weiss and colleagues have found that a kind of gas whose behaviour is governed by quantum-mechanical rules does the equivalent of this oscillating separation trick. When a so-called Bose gas, an ultracold cloud of a few tens or hundreds of rubidium atoms, is confined in a slit-shaped trap made from laser beams, it keeps splitting apart into two blobs that drift indefinitely back and forth between the ends of the trap.
The researchers say, in a paper in this week’s Nature, that this is equivalent to a quantum Newton's cradle - a quantum form of the well-known toy in which a row of balls suspended from a frame keeps alternately clacking the end balls out after the ball at one end is swung to collide with the next in line.
In physicists' terms, the trapped Bose gas refuses to thermalize: the atoms don't settle down into a statistically unchanging state as a result of collisions between them. They do collide, like the balls of a Newton's cradle - but these collisions don't randomize their energies until all the particles behave more or less identically. The researchers say that not only does their system offer a tool for theorists seeking to understand the complex behaviour of many-particle systems, but it might also find practical applications in, for example, an ultrasensitive force detector.
CONTACT
David Weiss (Pennsylvania State University, University Park, PA, USA)
Tel: +1 814 863 3076; E-mail: [email protected] <mailto:[email protected]>
Henk Stoof (University of Utrecht, Utrecht, The Netherlands)
Tel: +31 30 253 1871; E-mail: [email protected] <mailto:[email protected]>
[11] Astronomy: A new spin on Vega (pp896-899; N&V)
Vega, the second brightest star in the northern sky, is a 'standard' that has been used to calibrate astronomical observations from the ultraviolet through to the infrared, and it is the main star against which models of stellar atmospheres are compared. But problems with its use as a standard led to the suggestion that it is rapidly rotating. Peterson and colleagues now confirm that it is rotating so fast that if it sped up by just 10% it would spin to pieces, according to research published in this week’s Nature.
Vega is flattened significantly by the rotation, which means that the temperature at the star's surface varies hugely, being over 2,400 degrees Celsius hotter at the poles (around 10,000 degrees Celsius) than at the equator, because the equator is farther from the energy-generating centre.
This behaviour hasn't been obvious previously because it was obscured by Vega's orientation: its polar axis points more or less straight at the Earth. The new results imply that both Vega's elemental composition and its age may be rather different to what has been inferred until now.
CONTACT
Deane Peterson (Stony Brook University, Stony Brook, NY, USA)
Tel: +1 631 632 8223; E-mail: [email protected] <mailto:[email protected]>
Richard Gray (Appalachian State University, Boone, NC, USA)
Tel: +1 828 262 2430; E-mail: [email protected] <mailto:[email protected]>
[12] Cell signalling: Identifying the function of p110-alpha (AOP)
DOI: 10.1038/nature04694
***This paper will be published electronically on Nature's website on 12 April 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 13 April, but at a later date.***
The family of mammalian enzymes called phosphoinositide-3-OH kinases (PI(3)K) are fundamental cell signalling molecules whose exact roles have been difficult to pin down. Bart Vanhaesebroeck and colleagues show in a paper published online by Nature that one form of this enzyme, p110-alpha PI(3)K, is vital for cell growth and metabolism, findings that may help to explain why it is mutated in a variety of cancers.
The team tested the role of p110a by genetically engineering mice so that the enzyme was still manufactured at normal levels but no longer active. Mice carrying one copy of the defective gene did not respond normally to the hormones insulin, insulin-like growth factor-1 and leptin, and exhibited a range of growth and metabolic disorders as a result.
The study suggests that cancer cells may hijack cell growth pathways by increasing activation of p110-alpha, and supports the idea that blocking p110-alpha could block cancer growth.
CONTACT
Bart Vanhaesebroeck (Ludwig Institute for Cancer Research, London, UK)
Tel: +44 20 7878 4066; E-mail: [email protected] <mailto:[email protected]>
[13] And finally… Catfish hunts on land (p881)
The eel catfish can hunt and eat prey on land, according to video footage that may provide a clue as to how ancient fish made their first forays out of the ocean.
In a Brief Communication to this week's Nature, Sam Van Wassenbergh and colleagues reveal the remarkable behaviour of the eel catfish (Channallabes apus), a denizen of the muddy swamps of tropical Africa. The creature can raise itself out of the water, tilting its head downwards to engulf its prey in its mouth.
In water, C. apus feeds by rapidly expanding its mouth to suck up tasty morsels with a draught of water. On land, it makes similar movements to coax its dinner into its jaws, but the catfish must be able to bend its head downwards to avoid nudging the prey forwards and away from its mouth. C. apus has a specially adapted spine that allows it to move its head in this way, without the need for pectoral fins to support its weight.
CONTACT
Sam Van Wassenbergh (University of Antwerp, Antwerpen, Belgium)
Tel: +32 382 022 60; E-mail: [email protected] <mailto:[email protected]>
ALSO IN THIS ISSUE…
[14] Chemokines enhance immunity by guiding naive CD81 T cells to sites of CD41 T cell-dendritic cell interaction (pp890-895)
[15] Parametric oscillation in vertical triple microcavities (pp904-907)
[16] Deep origin and hot melting of an Archaean orogenic peridotite massif in Norway (pp913-917)
[17] IkB kinase-a is critical for interferon-a production induced by Toll-like receptors 7 and 9 (pp949-953)
[18] The reversibility of mitotic exit in vertebrate cells (pp954-958)
[19] Toxin-induced conformational changes in a potassium channel revealed by solid-state NMR (pp959-962)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 12 April 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 13 April, but at a later date.***
[20] Modulation of intracortical synaptic potentials by presynaptic somatic membrane potential
DOI: 10.1038/nature04720
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. 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.
AUSTRIA
Vienna: 14
BELGIUM
Ghent: 13
Wilrijk: 13
BRAZIL
So Paulo: 9
CHILIE
Santiago: 11
ETHIOPIA
Addis Ababa: 1
FRANCE
Marcaussis: 15
Marseille: 19
Paris: 15
Politiers: 1
Villeurbanne: 1
GERMANY
Dusseldorf: 9
Gottingen: 7, 19
Hamburg: 19
Mainz: 14
Nuthetal: 3
ITALY
Pavia: 16
Siena: 14
JAPAN
Chiba: 17
Kanagawa: 17
Osaka: 17
Sanda: 1
Tokushima: 17
Tokyo: 1
SOUTH AFRICA
Pretoria: 1
SWITZERLAND
Chaussee du Musee: 12
THE NETHERLANDS
Amsterdam: 16
Den Burg: 8
Leiden: 9
Nijmegen: 8
Utrecht: 16
UNITED KINGDOM
Cambridge: 12
Edinburgh: 12
London: 9, 12
UNITED STATES OF AMERICA
Arizona
Flagstaff: 11
Tempe: 3
California
Berkeley: 1, 2
Emeryville: 2
Los Angeles: 5
Rocklin: 1
Connecticut
New Haven: 1, 20
District of Columbia
Washington: 1, 11
Illinois
Urbana: 1
Maryland
Bethesda: 14
Seabrook: 11
Massachusetts
Boston: 6
Cambridge: 6
Michigan
Ann Arbor: 4, 5, 9
Minnesota
St Paul: 4
Nebraska
Lincoln: 4
New Jersey
Princeton: 5
New Mexico
Los Alamos: 1
New York
New York: 14
Stony Brook: 11
Ohio
Cleveland: 1
Kent: 1
Oxford: 1
Oklahoma
Oklahoma City: 18
Pennsylvania
University Park: 10
Utah
Salt Lake City: 3
Virginia
Charlottesville: 18
Herndon: 11
Washington
Seattle: 3
PRESS CONTACTS…
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected] <mailto:[email protected]>
For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected] <mailto:[email protected]>
For the UK/Europe/other countries not listed above
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected] <mailto:[email protected]>
Victoria Picknell, Nature London
Tel: +44 20 7843 4502; E-mail: [email protected]
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