Nature press release for 14 March issue

The hyped ability of adult stem cells to sprout numerous different cell types is questioned by two Nature reports published online this week. They may instead be fusing with existing cells, say two new reports, creating cells with double the dose of chromosomes and unknown health consequences.
Recent studies have shown that adult stem cells from one tissue such as blood, can give rise to other cell types, such as nerve and muscle. The adult cells are thought to revert to a state similar to embryonic stem cells, able to make many other cell types in the body.
Austin Smith of the University of Edinburgh, UK, and Naohiro Terada of the University of Florida in Gainesville suggest that spontaneous cell fusion could be occurring instead. They found that adult cells from either bone marrow or brain grown in the same dish as embryonic stem cells fused spontaneously to make hybrid cells, which were able to produce muscle, nerve and other cell types.
Smith and Terada only tested whether this could occur in a petri dish. Animal studies will be required to confirm that spontaneous cell fusion occurs in vivo, and that it provides an alternative explanation for recent demonstrations of adult stem cell plasticity.
If confirmed by animal studies, the findings could be a reality check for those hoping to use adult stem cells clinically. Fused cells carry double the normal amount of DNA, and may be unhealthy. "It might be a precautionary tale for stem cell research," says Terada.
CONTACT:
Austin Smith tel +44 131 650 5890, e-mail Austin.smith@ed.ac.uk
Naohiro Terada tel +1 352 392 2696/2690, e-mail terada@pathology.ufl.edu

[416141] BRAIN: THINK IT, DO IT (pp141-142)

A new algorithm that allows monkeys to move a computer cursor in real time just by thinking about it raises hope that paralysed humans could one day control robotic limbs in a similar way. Until now the application of such devices has needed extensive training or been confined to a limited movement repertoire.
The new system, which is suitable for human use, is described in this week`s Nature. It decodes activity from just a few neurons in the monkey`s motor cortex. The animal`s resulting hands-free cursor control was almost as fast and accurate in pursuing a target as when they used their hands.
Mijail D. Serruya and colleagues of Brown University, Rhode Island, explain their methods and results in a Brief Communication.
CONTACT:
Mijail D. Serruya tel +1 401 273 9851, e-mail mijail_serruya@brown.edu

[416150] SPACE: UNIVERSE MODEL PASSES TEST (pp150-152; N&V)

Astrophysicists can relax. Data from the Very Large Array sky survey of distant radio sources has confirmed an idea central to our view of the Universe.
The idea is that the 2.7 K cosmic microwave background (CMB) radiation originated as the Universe cooled after the Big Bang, and matter and radiation became decoupled. Current cosmological models would be invalidated if the CMB was in fact generated locally.
One test for a cosmic origin — now carried out and reported in this week`s Nature —would be the confirmation of a Doppler effect. As the Earth moves towards and away from distant radio galaxies, the number count of galaxies should show the same directionality as the CMB and at the predicted amplitude. Fortunately, it does seem to, say Chris Blake and Jasper Wall of the University of Oxford, UK.
"With yet another observational success behind them, theoretical cosmologists can be pleased that their basic model remains remarkably successful," says George F. R. Ellis of the University of Cape Town, South Africa, in an accompanying News and Views article.
CONTACT:
Chris Blake tel +44 1865 273508, e-mail cab@astro.ox.ac.uk
George F. R. Ellis tel +27 21 650 2339, e-mail ellis@maths.uct.ac.za

[416152] EARTH: BLUE JET CAUGHT ON CAMERA (pp152-154)

Lightning-like light flashes called blue jets may link the electrical energy of thunderstorms and the charged layer of the upper atmosphere, according to new research in this week’s Nature.
Victor Pasko at Pennsylvania State University and colleagues used high-speed, low-light cameras to capture an image of a fleeting blue jet that extended from the top of a thunderstorm all the way up to the ionosphere, 70–80 kilometres above the ground.
Blue jets are caused by electrical current shooting upwards out of thunderclouds, ionizing molecules in the atmosphere and making them glow. Previous measurements suggested that blue jets could only reach about 40 kilometres high.
The finding satisfies a long-held belief that something must provide a link between the electrical charge of the ground and the oppositely charged ionosphere — a difference of some 300,000 volts.
Moreover, the blue jet reported here was associated with a small and localized thunderstorm — such storms occur constantly world-wide. This suggests that large blue jets are common. Their ionizing power could even make important contributions to atmospheric chemistry, such as fixing nitrogen and manufacturing ozone.
CONTACT:
Victor Pasko tel +1 814 865 3467, e-mail vpasko@psu.edu

[416165] RELICS: THE PATAGONIAN CANDIDATE (pp165-168)

The Jurassic (208–145 million years ago) was a crucial period for mammal evolution, but the tally of known Jurassic mammals is sparse, especially in the southern continents, which are believed to be the location for many important evolutionary events.
This week Thomas Martin of the Freie Universit'�t Berlin, Germany, and colleagues at the Museo Paleontol'�gico Egidio Feruglio, Trelew, Argentina, describe the jaw of a Jurassic mammal from Patagonia. This may be the first Jurassic mammal from South America.
This find is important because it bears on a controversial theory of mammal evolution first proposed in Nature a year ago (see Nature 409, 53–57; 2001). This theory suggested that the complex, crushing molars of mammals originated not once, but twice: in the Northern Hemisphere in animals that gave rise to nearly all the mammals alive today, and in the Southern Hemisphere in a group of mammals now extinct except for the egg-laying monotremes (the platypus and echidna).
The anatomy of the new Patagonian specimen shows that it belongs to this southern group. As such, it may provide the first independent confirmation of this contentious view of mammalian evolution.
CONTACT:
Thomas Martin tel +49 307 792 276, e-mail tmartin@zedat.fu-berlin.de

[416159] EARTH: DUST DESERTS (pp159-163)

Desert conditions prevailed in central Asia 22 million years ago — at least 14 million years earlier than previously thought. So suggest wind-blown dust deposits found in China, and described in this week`s Nature.
Uplift of the Himalayan–Tibetan plateau and changes in land–sea distribution are thought to have driven the climate deterioration in the area that started about 66 million years ago.
The initial desertification of the Asian interior is important in this sequence of events, but its date had been hitherto uncertain. Zhentang Guo of the Chinese Academy of Sciences and co-workers now push back the time of the transition from a temperate to an extreme climate.
CONTACT:
Zhentang Guo tel +86 10 826 17629, e-mail ztguo@95777.com

[416168] ECOLOGY: PRODUCTION NUMBER (pp168-171)

In some warmer regions in the oceans CO2 production exceeds consumption, with the excess CO2 contributing to the atmospheric carbon budget, research published in this week`s Nature confirms.
Hans-Georg Hoppe and colleagues of the University of Kiel, Germany, analyse measurements taken from the Polarstern research vessel cruising along a transect from the North Atlantic to the South Atlantic. They show that the balance of algal activity and bacterial activity, which determines the oceanic carbon cycle, varies with water temperature. The balance is such that in warm latitudes there are areas where the net flux of CO2 to the atmosphere is positive.
This demonstrates that the contributions bacteria and phytoplankton make to the oceanic carbon cycle are directly linked to climate.
CONTACT:
Hans-Georg Hoppe tel +49 431 597 3945, e-mail hhoppe@ifm.uni-kiel.de

[416174] LIFELINES: NEW MOVEMENT (pp174-178; N&V)

Fruit fly embryos and larvae that have been genetically modified to have either no sensory function or almost no sensory neurons nonetheless move, researchers report in this week`s Nature.
The results are from Maximiliano Suster and Michael Bate of the University of Cambridge, UK. They show that the foundations of the central circuits that produce rhythmic movements such as flying, swimming or breathing can develop and function in the absence of sensory inputs. The work offers hope that genetic manipulations in organisms such as rodents could further the study of reflex pathways in the control of movement.
"It will be fascinating to see how the neuronal properties and synaptic connectivity of the circuits that control movement in these flies compare with those that develop normally, says Eve Marder of Brandeis University, Waltham, Massachusetts, in an accompanying News and Views article.
CONTACT:
Maximiliano Suster (currently at the University of Toronto, Missassauga, Canada) tel +1 905 569 4707, e-mail msuster@credit.erin.utoronto.ca
Eve Marder tel +1 617 736 3140/3141, e-mail marder@brandeis.edu

[416163] CLIMATE: TROPICAL PLANTS BALANCE BOOKS (pp163-165)

Common tropical plants emit large amounts of methyl chloride, one of the most important natural ozone-depleting compounds, researchers report in this week`s Nature. This previously overlooked source could account for a large proportion of atmospheric methyl chloride, whose provenance was previously something of a mystery.
The finding raises questions about future and past atmospheric methyl chloride levels, given the changing fate of the tropical rainforests, say researchers Yoko Yokouchi of the National Institute for Environmental Studies, Tsukuba, Japan, and colleagues.
CONTACT:
Yoko Yokouchi tel +81 298 50 2549, e-mail yokouchi@nies.go.jp

PHYSICS: INSIGHT ON ULTRACOLD MATTER

This month`s Nature Insight collection of review articles covers some of the highlights of recent research into ultracold matter — a field that has seen two Nobel prizes within the past five years.
Under unimaginably cold conditions, new types of physical behaviour await our discovery. As the thermal motions of atoms and molecules become progressively smaller, the elusive quantum world — usually masked at higher temperatures — comes into focus.
Superfluidity of liquid helium, first observed in the 1930s, is one of the earliest and most tangible examples. Although this phenomenon occurs at just 2 K, modern laser-cooling technology can attain much lower temperatures. So what happens when we skim absolute zero? For atomic gases, this question was answered dramatically in 1995 with the production of a quantum state of matter known as a Bose–Einstein condensate.
Formed at nanokelvin temperatures, a condensate is a cloud of atoms that pays no heed to everyday physical rules; atomic identities are lost as the particles blur into a coherent quantum entity. Condensates and superfluids are inextricably linked, yet many questions surround their relationship. The main difference between atomic gas condensates and superfluid helium lies in the strength of the particle interactions, which are much weaker in the former system.
This simplifying feature of Bose–Einstein condensates makes them extremely attractive for theoretical studies. A source of coherent atoms also provides a wonderful practical tool. Just as the development of the laser revolutionized optics, so the ability to generate coherent matter waves opens up exciting research possibilities.
Nonlinear optical processes such as four-wave mixing can now be carried out using atoms in place of photons; matter–wave amplification has been observed, and atomic analogues of optical ‘squeezed’ states realized. Although Bose–Einstein condensation is one of the triumphs of laser-cooling technology, it is by no means the only success story. Individual ultracold atoms and ions are also enormously versatile, making an impact in fields such as metrology and quantum information processing.

The full set of papers for this Insight can be found on the Nature Journals Press Site.

[416142] LIFELINES: TWINS DON’T COMPETE (p142)

"The presence of one embryo does not affect the development of its twin". So suggests a Brief Communication in this week`s Nature. In a group of women who released two eggs at once, the probability of both eggs becoming fertilized and developing successfully is the same as for a single egg release: 20–30%.
The prevailing view is that losses of the second fertilized egg are high very early in pregnancy, and that for every liveborn twin pair, there are 10–12 more that end in a single birth. The study casts doubt on, but does not rule out, the possibility that both twins might be lost at a higher rate than singletons.
Steven Tong of Monash University, Victoria, Australia, and colleagues used ultrasound to follow 504 pregnancies, 48 of which started in double ovulation. "The presumption of huge losses of dizygotic twins in early pregnancy is unfounded," they conclude.
CONTACT:
Steven Tong tel +61 3 9594 5362, e-mail stephen.tong@med.monash.edu.au

[416172] …AND FINALLY: DEPTH SOUNDED OUT (pp172-174)

Norimichi Kitagawa and Shigeru Ichihara of the Tokyo Metropolitan University describe an intriguing auditory illusion in this week`s Nature.
After watching a square on a computer monitor move seemingly towards and away from them, volunteers hear a steady tone as changing in volume. They say it seems louder when the square is further away and softer when the shape appears closer. Altering the volume while keeping the square stationary does not affect volunteers` opinion of the depth of the square.
This is yet another example of the favouritism the human brain affords visual stimuli over other sensory inputs, say the researchers. For instance, if we experience a sound and an image from different locations, we perceive the sound to come from the location of the image — called the ventriloquism effect.
CONTACT:
Norimichi Kitagawa tel +81 426 77 2094, e-mail kitagawa@bcomp.metro-u.ac.jp

ALSO IN THIS ISSUE…

 Formation of isomorphic Ir3+ and Ir4+ octamers and spin dimerization in the spinel CuIr2S4

 Cbl-CIN85-endophilin complex mediates ligand-induced downregulation of EGF receptors

 The endophilin-CIN85-Cbl complex mediates ligand-dependent downregulation of c-Met

 Involvement of receptor-interacting protein 2 in innate and adaptive immune responses

 RICK/Rip2/CARDIAK mediates signalling for receptors of the innate and adaptive immune systems

Nature Publishing Group Reference

RSS Feeds

Nature press release for 14 March issue

Science Research Departments