---

---

---

---

Science RSS News Feeds

---

---

Email a Friend Printer Friendly

Nature press release for 13 September issue

September 13, 2001

[413127] PHENOMENA: STAGGERED CYCLISTS STAY APART (p127)
Staging cycling and orienteering races to prevent the competitors forming into packs may be helped by a Brief Communication in this week’s Nature. In races, cyclists in a pack can move faster than those alone, by taking turns to front the pack and sharing the benefits from reduced air resistance. Orienteers can also profit from travelling in packs by sharing map-reading information. But this makes it difficult to compare the true ability of individuals.
Graeme Ackland and David Butler of the University of Edinburgh, UK, constructed a model to predict race conditions that precipitate pack formation. If 13% of competitors can see and catch up with the competitor ahead, all competitors are rapidly swept into packs, they discovered. Staggering the start of the race sufficiently could stop competitors bunching up.
In events such as triathlons, time spent in the first-stage swim could be lengthened to stagger the start of the cycling phase, the authors suggest,
and avoid packs forming. This makes a fairer race, and a “better spectacle,” they say.
CONTACT:
Graeme Ackland tel +44 131 650 5291, e-mail g.j.ackland@ed.ac.uk

[413131] LIFELINES: PGC-1 KEEPS LIVER SWEET (pp131-138, 179-183; N&V)
Diabetes therapy gets an important new lead from two papers in this week’s Nature. Two groups report that the protein PGC-1 is the elusive cornerstone of the pathway that regulates healthy glucose metabolism in the liver. This pathway is defective in type 1 and type 2 diabetes.
Glucose is the mammalian brain’s main fuel. So sophisticated control systems maintain blood glucose levels within tight limits in the face of large fluctuations in food and carbohydrate intake.
Suppressing PGC-1 inhibits the generation and the breakdown of glucose in cultured liver cells and in living rats, say Bruce M. Spiegelman of Dana-Farber Cancer Center, Harvard Medical School, Boston, Massachusetts, and colleagues, and Marc Montminy of the Salk Institute for Biological Studies, La Jolla, California, and colleagues.
“Together these papers present a convincing body of data implicating PGC1 as a key signalling element involved in coordinating the hepatic metabolic response to fasting,” say Antonio Vidal-Puig and Stephen O’Rahilly of the University of Cambridge, UK, in an accompanying News and Views article. The improvement in our knowledge of the molecular controls of glucose production in the liver “may permit the design of more specific targeted therapies.”
CONTACT:
Bruce M. Spiegelman tel +1 617 632 3567, e-mail bruce_spiegelman@dfci.harvard.edu
Marc Montminy tel +1 858 453 4100 x 1394, e-mail montminy@salk.edu
Stephen O’Rahilly tel +44 1223 336855, e-mail sorahill@hgmp.mrc.ac.uk

[413129] ECOLOGY: PLANTS AT RISK FROM HORMONE-LIKE POLLUTANTS? (p128-129)
New evidence that oestrogen mimics can disrupt a critical signalling pathway in plants adds to concerns about the effects of hormone-like industrial chemicals on aquatic animals and humans.
Much of the nitrogen in living organisms is ‘fixed’ from the atmosphere by bacteria that live in the roots of leguminous plants. This symbiotic relationship is controlled by chemical signals passing between plant and bacteria.
Jennifer Fox and colleagues of Tulane University, New Orleans, Louisiana, find that some compounds that disrupt oestrogen-linked effects in mammal cells can also suppress the genes in alfalfa (Medicago sativa) that signal to its partner bacterium, Sinorhizobium meliloti. In a Brief Communication, Fox’s team writes that the finding “[extends] the biological and ecological impact of endocrine-disrupting chemicals”.
CONTACT:
Jennifer Fox tel +1 504 988 6623, e-mail jfox3@tulane.edu

[413139] SPACE: BLACK-HOLE VELOCITY KICKS OUT KICK MODEL (pp139-141)
Demonstrating the potential of very long baseline interferometry, research in this week’s Nature determines the space velocity of a black hole in the halo of the Milky Way. Only a few of the dozen known stellar-mass black holes lie out of the plane of our Galaxy. These bodies could have been shot out from the Galaxy as a result of a ‘kick’ from a supernova explosion, or could be the remains of massive stars formed early during the life of the Galaxy.
I. F. Mirabel of the Service d’Astrophysique/CEA, Gif sur Yvette, France, and the Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina, and colleagues, calculate an orbit of the black hole XTE J1118+480 that virtually rules out the supernova ‘kick’ model, suggesting that it is part of the old halo component.
CONTACT:
I. F. Mirabel tel +33 1 690 89256, e-mail fmirabel@cea.fr

[413154] EVOLUTION: FORK FIGHT HOTS UP (pp154-157, 157-161; N&V)
The interrelationships of arthropods — the jointed-legged animals that together make up 84% of all known species — is a hot issue in evolutionary biology. Researchers are debating alternative evolutionary trees reconstructed from different kinds of evidence. This debate is exemplified by the different conclusions of two analyses of arthropods presented in this week’s issue of Nature.
Markus Friedrich, of Wayne State University, Detroit, Michigan, and colleagues, produce a new, two-forked family tree using molecular data that include the mitochondrial genome of the European centipede Lithobius forficatus. They put the myriapods (centipedes and millipedes) most closely related to chelicerates (spiders, scorpions and allies), and reaffirm earlier work by presenting a united insect–crustacean group.
Gonzalo Giribet, of Harvard University, Cambridge, Massachusetts, and colleagues, report a more traditional result. They conclude that insects and crustaceans are closely related, with myriapods as cousins to this group, and chelicerates standing further away. The interest of this research lies less in the result than in the method. Giribet’s group combined molecular and anatomical data in a controversial ‘total evidence’ analysis, crunching the huge amounts of data with a custom-built parallel computer (see news story in Nature 404, 214, 16 March 2000).
In a News and Views article, Mark Blaxter of the University of Edinburgh, UK, discusses the implications of these contradictory findings.
CONTACT:
Markus Friedrich tel +1 313 642 0819, e-mail mf@biology.biosci.wayne.edu
Gonzalo Giribet tel +1 617 495 1473, e-mail ggiribet@oeb.harvard.edu
Mark Blaxter tel +44 131 650 6760, e-mail mark.blaxter@ed.ac.uk

[413142] PHYSICS: LIGHT DIFFRACTS ELECTRONS (pp142-143; N&V)
Almost 70 years after it was first proposed, an experiment has shown that light waves can diffract electrons. The result, reported in this week’s Nature, highlights the interchangeable roles of matter and light.
Herman Batelaan and colleagues at the University of Nebraska, Lincoln, report the first observation of coherent interference patterns arising from the interaction between free electrons and a standing light wave — the so-called ‘Kapitza–Dirac’ effect predicted in 1933. This is analogous to the way an array of narrow holes splits one light beam into several.
“The work could have interesting consequences for studies of quantum chaos and for the design of novel electron interferometers,” explains Philip H. Bucksbaum of the University of Michigan, Ann Arbor, in an accompanying News and Views article that discusses the history behind this research and its ramifications.
CONTACT:
Herman Batelaan tel +1 402 472 3579, e-mail hbatelaan2@unl.edu
Philip H. Bucksbaum tel +1 734 764 4348, e-mail phb@umich.edu

[413171] LIFELINES: BREATH OF FRESH AIR (pp171-174; N&V)
Anyone who has climbed to high altitudes or even sprinted for a bus knows we breathe harder when we need more oxygen. Research in this week’s Nature sheds light on the ill-understood physiological mechanisms behind this phenomenon.
It was thought that the oxygen bound to haemoglobin in the blood, or a lack of it, regulated the process. Benjamin Gaston of University of Virginia School of Medicine, Charlottesville, and colleagues, report that our response to hypoxia (lack of oxygen) is in fact controlled by a group of molecules related to a completely different gas — nitric oxide (NO).
Gaston’s team find that compounds called S-nitrosothiols (SNOs) bind to haemoglobin much like oxygen and act at all levels of breathing regulation. SNOs, it turns out, cause blood vessels and airways to dilate, signal the oxygen needs of tissues, and communicate with the region of the brain involved in the desire to breathe. The involvement of SNOs in respiration could offer new insights into treatments for breathing disorders, the researchers say.
The findings are described as “radical” by Stuart Lipton at the Burnham Institute in La Jolla, California, in an accompanying News and Views article. “The paper will make it into the physiology textbooks,” he writes in an accompanying News and Views article.
CONTACT:
Benjamin Gaston tel (until 9 Sept) +1 804 924 1820, (10-13 Sept, in Utrecht, Holland) +31 30 2537356 / +31 30 2313169, e-mail bmg3g@virginia.edu
Stuart Lipton tel +1 858 713 6261, e-mail slipton@burnham-inst.org

[413144] PHYSICS: FISSION AND FUSION NEED RETHINKING (pp144-147; N&V)
Physicists may have to rethink their model of nuclear fission and fusion, a report in Nature this week suggests.
Unstable superheavy elements (with atomic numbers above 82) can be created by fusing two highly charged stable nuclei in a process analogous to colliding droplets of liquid. Instead of undergoing fusion to form a single heavy nucleus, the system almost always separates in a process known as quasi-fission, involving transfer of mass from the heavier of the two nuclei to the lighter one. Theory predicts that this fusion-inhibiting process should occur when the product of the two nuclear charges exceeds a threshold value.
New measurements from D. J. Hinde and colleagues at the Australian National University, Canberra, show that formation of superheavy nuclei is actually inhibited at about half of this theoretical value.
The work “should stimulate further experimental and theoretical investigations of the processes behind superheavy fusion reactions,” says Yuri Oganessian of the Joint Institute for Nuclear Research, Moscow, Russia, in an accompanying News and Views article.
CONTACT:
D. J. Hinde tel +61 2 612 52094, e-mail djh103@nuc.anu.edu.au
Yuri Oganessian fax +7 09621 65083, e-mail oganessian@flnr.jinr.ru

LIFELINES: MAKING SENSE OF SENSE
This month’s Insight supplement explores the first, crucial step in sensory processing — the translation or ‘transduction’ of stimuli, such as odour, light and sound, into a cellular response. This takes place in specialized cells somewhere between our environments and our nervous systems. Each sense has evolved a transduction mechanism so finely tuned that it is able to discriminate between different stimuli with both speed and sensitivity.
The supplement rounds up the past few years’ explosion in the identification of molecules involved in the different transduction mechanisms. This year is the tenth anniversary of the discovery of the first odour receptors. These belong to a large family of G-protein-coupled receptors, which amplify signals via intracellular signalling cascades — a mechanism shared by several other senses including vision and taste.
The collection of expert review articles demonstrates the vast diversity of signals that our senses encode. It is remarkable that evolution has repeatedly called upon two ion-channel families to impart such functional diversity. TRP channels were discovered in the fruitfly, where they are involved in the transduction of light and touch. Another family member, VR1, has a role in detection of noxious heat by mammals. Similarly, DEG/ENaC family members are involved in senses ranging from touch in nematodes to mineral taste in mammals. Small wonder, then, that such molecular switches are being engineered for use in commercial biosensor devices.
CONTACT:
Jo Webber (Nature press office) tel +44 20 7843 4571, e-mail j.webber@nature.com

[413128] …AND FINALLY: A LONG STORY (p128)
Most male birds don’t have penises, but the Argentine lake duck (Oxyura vittata) convincingly ups the average. Its member is as long as its body — the record for any bird.
The giant penis may be an example of ‘runaway’ sexual selection, where female preference drives male anatomy to ever greater extremes, as in the peacock’s tail. The penis also has a brush-like tip, which males probably use to scrub the sperm of previous mates from the female’s oviduct.
In a Brief Communication, Kevin McCracken of the University of Alaska, Fairbanks, and colleagues, extend an earlier estimate of the length of the duck’s corkscrew-shaped penis.
CONTACT:
Kevin McCracken tel +1 907 474 6945, e-mail fnkgm@uaf.edu


Nature Publishing Group Reference