Nature press release for 15 August issueAugust 20, 2002[1] LIFELINES: APES LACK ELEMENTS OF LANGUAGE GENE (DOI: 10.1038/nature01025) (http://dx.doi.org/10.1038/nature01025) ***This paper will be published electronically on Nature`s website on 14 August at 1900 London time / 1400 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 15 August, but at a later date.*** Language, a uniquely human trait, relies on capabilities such as fine control of the larynx and mouth. In a paper published online in Nature this week, researchers have begun to work out why chimpanzees and other great apes lack these abilities. Last year, scientists identified the first gene, called FOXP2, definitively linked to human language; members of a family with mutations in this gene have severe language and grammar difficulties. Human FOXP2 contains a key change in its sequence compared with the other animals, they found, and is under selection for the human-specific change. The sequence changes may affect a person`s ability to control facial movements and thus to develop proficient spoken language, they speculate. The gene variant that permits language may have become widespread in the population during the last 200,000 years of human history, they estimate - around the same time that anatomically modern humans emerged - suggesting that language may have been a driving force in their expansion. CONTACT: [2] LIFELINES: CROSS-SPECIES TESTES TRANSPANT (pp778-781) Researchers have produced sperm from pig and goat testes grafted onto mice. Future human-to-mouse grafts could help restore fertility to men who have undergone cancer therapy, and other interspecies grafts could help conserve endangered species. Scientists have previously grafted testis tissue from one mouse to another - but previous grafts between mammalian species have not produced sperm. Ina Dobrinski of the School of Veterinary Medicine, University of Pennsylvania, Kennett Square, and colleagues devised a technique to graft fragments of tissue from immature testes of newborn pigs or goats under the skin of mice whose immune systems were deficient. More than 60% of the grafts survived and produced working sperm, they report in Nature. Unlike sperm cryopreservation, grafting testis tissue from humans into a mouse host and use of the resultant sperm for assisted fertilization provides a potentially endless supply of sperm. Testis tissue grafts could also contribute to conserving endangered species or valuable livestock by allowing sperm production from immature males. It could also be used as a method for studying the effects of toxins and male contraceptives on testis function. CONTACT:
Two papers in Nature this week describe a bizarre light phenomenon created by excitons, bound pairs of electrons and holes that can form in semiconductor systems. Light from excitons generated by a laser pulse in quantum wells appears up to 1 millimetre away from the laser excitation spot with almost none in between, say L. V. Butov of the Lawrence Berkeley National Laboratory, University of California, Berkeley, and the Russian Academy of Sciences, Chernogolovka, and colleagues, and D. Snoke of the University of Pittsburgh, Pennsylvania, and his team. This is like a drop falling into water - but only a single circular ripple appearing some distance away. The finding implies that excitons must travel in a dark state and then revert to a luminescent state at a critical distance. Physicists hope to use measurements of excitons, which can form quantum liquids at low temperatures, to understand other quantum liquids such as superconductors, liquid helium and Bose-Einstein condensates, whose ordered structures are very difficult to probe. CONTACT:
US scientists have created transgenic mice whose muscles tire slowly during exercise. Human skeletal muscles contain about half slow-twitch and half fast-twitch fibres. Slow-twitch muscles are the ones that can cope with the repeated muscle contractions required for endurance, in part because they contain more energy-generating mitochondria. Bruce M. Spiegelman of the Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, and his team made transgenic mice that produce the `slow-twitch` protein PGC-1 - which switches on mitochondrial proliferation and metabolism - in muscle cells that are normally fast-twitch. The muscle fibres convert to slow-twitch, they show in this week's Nature, and as a consequence are more resistant to fatigue. CONTACT:
A protein that intensifies and prolongs caffeine`s kick is identified in this week`s Nature. Although caffeine is probably the world's most widely used psychostimulant, surprisingly little is known about its molecular mechanism. At concentrations equivalent to a few cups of coffee a day, it binds and blocks nerve cells that normally inhibit voluntary movements in the brain`s movement centre, the striatum. Gilberto Fisone of the Karolinska Institute, Stockholm, Sweden, and colleagues found that a protein called DARPP-32 is the key to the action of coffee: mice genetically engineered to lack DARPP-32 are immune to some of its stimulatory effects, they report. Low doses of caffeine appear to trigger a positive feedback loop in striatal nerves: they subdue a protein called protein kinase A, which in turn keeps DARPP-32 phosphorylated. In this form, it dampens protein kinase A further. Together with other molecules in the feedback loop, they control the activity of further proteins that inhibit nerve activity, and thus keep us hyperactive. "DARPP-32 keeps us going until the next coffee break by extending the effects of the last cup," says Jean-Marie Vaugeois of the University of Rouen, France, in an associated News and Views article. CONTACT:
The discovery that magnesium diboride (MgB2) can superconduct at remarkably high temperatures (39 kelvin) generated much excitement in the field: MgB2 is cheap, readily available, and may even be amenable to being made into wires. In this week`s Nature, Steven G. Louie of the University of California at Berkeley, and the Lawrence Berkeley National Laboratory, Berkeley, and colleagues have come up with a model to better understand MgB2`s superconducting properties. Materials carry a superconducting current when electrons are induced to form pairs. The tracer of the binding energy of the pairs is called the energy gap, because energy put into the superconductor is absorbed by the pairs to separate the electrons. Recent experiments indicate that electrons in MgB2 may have two different binding energies. The new model confirms its `double-energy-gap` nature - and predicts many of the remarkable characteristics of MgB2 as a superconductor. CONTACT:
There is a long history of attempts to develop antimalarial vaccines, but little success. All current malarial vaccine candidates are aimed at target proteins in the various life stages of the malarial parasite, Plasmodium falciparum. Louis Schofield of the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, and colleagues show, using a mouse malaria model, that a vaccine targeted at a toxin released by the parasite may be more effective. Mice inoculated with a chemically synthesized fragment of glycosylphosphatidylinositol (GPI) were protected against many of the signs of malaria, and against death. The findings demonstrate the potential of synthetic GPI in anti-toxic vaccines, and suggest that GPI is responsible for some symptoms of malaria in humans. CONTACT:
Why volcanoes in the northwest Pacific Ocean once spouted huge volumes of magma may be explained in this week`s Nature. Vadim Levin of Yale University, New Haven, Connecticut, and colleagues took seismic images in the upper 200 kilometres of the Earth. They pictured a region where the Aleutian and Kamchatka subduction zones - places where one tectonic plate plunges below another - meet. In this region, the Pacific plate and North American plate also collide. The second piece of broken-off slab forced down into the hot mantle might have caused huge upflow of hot material, explaining the world-record magma output of the overlying Klyuchevsky volcano, they suggest. Confirming this theory will require investigation of similar geological regions in the world, says J. Huw Davies of Cardiff University, UK, in an accompanying News and Views article. CONTACT:
The gossamer-like product of the silkworm`s toil is getting a bad rap, according to a Brief Communication to this week`s Nature. The strength and flexibility of their silk can be nearly as good as that of spiders - currently championed as producers of the ultimate silk - provided it is extracted under the right conditions. Zhenghong Shao of Fudan University in Shanghai, China, and Fritz Vollrath, at Oxford University, UK, show that by carefully extracting silk directly from silkworms (the caterpillar of the silk moth, Bombyx mori) rather than from finished cocoons, the properties of the resulting silk approach spider quality. Previous experiments showed that silk from web-spinning spiders is about three times as strong and more than twice as stretchy as silkworm silk. But these experiments compared spider silk with silkworm silk extracted in the way used to produce silk commercially - by washing and unwinding it from caterpillar-spun cocoons. But spooling silk as it comes out of the caterpillar`s silk glands changes its properties markedly, Shao and Vollrath find. Slow spooling makes silkworm silk as stretchy as spider silk, and fast spooling makes it tougher, although not quite as strong as spider silk. They argue that materials with the desirable properties of spider silk could be harvested commercially either by inducing silkworms to spin in a different way or by modifying silk collection techniques, without having to resort to genetically engineering silkworms (which has been suggested). Harvesting silk from spiders is not regarded as feasible. CONTACT:
Temperature is crucial to changes in the life stages of the parasite responsible for malaria, according to a Brief Communication to this week`s Nature. To pass from mosquito to human and back to mosquito again, the parasite Plasmodium falciparum must go through three life stages, one that goes from mosquito to human, one that reproduces in the human, and one that returns to mosquitoes. Jun Fang and Thomas McCutchan at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, find that certain genes in P. falciparum are transcribed more efficiently at cooler temperatures. This thermoregulatory adaptation could be crucial to how the parasite copes with changes in temperature when it moves between hosts. CONTACT:
A letter to this week`s Nature reports good news for Tarzan, but potentially bad news for our climate`s future. Oliver Phillips of Leeds University, UK, and colleagues report that the numbers of lianas - tree-climbing vines and preferred mode of transport for the king of the jungle - are increasing in the Amazon rainforest. In some parts of the forest they are nearly twice as many big lianas now than there were twenty years ago. Tree-killing lianas, the researchers argue, could reduce the ability of tropical forests like the Amazon to absorb greenhouse gas carbon dioxide. Lianas break tree limbs and block out sunlight, causing trees to grow slower and convert less carbon dioxide into plant material. The reason for the increase in lianas remains unclear. But the researchers speculate that, paradoxically, increasing levels of carbon dioxide in the atmosphere could be feeding liana growth. The finding, they argue, shows the importance of `biosphere feedbacks` - changes in climate or atmospheric conditions affecting ecosystems like forests, which change how they in turn have an impact on the climate and atmosphere. CONTACT:
[12] The influence of a chemical boundary layer on the fixity, spacing and lifetime of mantle plumes (pp760-763) [13] A primitive fish close to the common ancestor of tetrapods and lungfish (pp767-770) [14] Mechanism of regulation of WAVE1-induced actin nucleation by Rac1 and Nck (pp760-793; N&V) [15] Modulation of an RNA-binding protein by abscisic-acid-activated protein kinase (pp793-797)
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. AUSTRALIA BOLIVIA CHINA DENMARK ECUADOR GERMANY ITALY JAPAN PERU RUSSIA SWEDEN UNITED KINGDOM UNITED STATES OF AMERICA | |||||||||||||||||||||
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