hello tweets.

i just received this message and thought i'd share it with you.

regards,

Deborah Wisti-Peterson email:nyneve at u.washington.edu
Department of Zoology, University of Washington, Seattle, Wash, USA
Visit me on the web: http://students.washington.edu/~nyneve/
<><><>Graduate School: it's not just a job, it's an indenture!<><><>

>
> [1][LINK] FOR IMMEDIATE RELEASE: 3 MARCH 2000 (3 MARCH 2000 GMT)
>
> Contact: Jim Barlow, Life Sciences Editor
> [2]b-james3 at uiuc.edu
> 217-333-5802
> [3]University of Illinois at Urbana-Champaign
>
>
> Champaign, Ill. -- A blue-light photoreceptor found in nerve layers
> of the eyes and brains has caught the attention of University of
> Illinois researchers who are seeking the magnetic compass that lets
> migratory birds and many other creatures find home using the
> magnetic field of Earth.
>
> The receptor -- cryptochrome -- is known to play a prominent role
> regulating an animal's day-and-night rhythm. Now, UI scientists
> report in the February issue of the Biophysical Journal that
> chemical experiments and computational modeling indicate that
> cryptochrome may be the site of a neurochemical reaction that lets
> birds, for example, process visual clues from the magnetic field
> and stay on course.
>
> "Animals as diverse as migratory birds, salamanders, salmon, or
> hamsters use the geomagnetic field for orientation," said Klaus
> Schulten, holder of the UI Swanlund Chair in Physics and professor
> at the Beckman Institute for Advanced Science and Technology. "We
> know how such a compass works in bacteria, and we know that the
> magnetic compass ability is widespread in animals. But it has been
> a mystery how magnetoreception is achieved in higher animals."
>
> Typical biomolecules interact with Earth's magnetic field too
> weakly to alter the course of their chemical reactions. In earlier
> experiments, Schulten had shown that certain chemical reactions
> involving so-called radical pairs can be influenced by weak
> magnetic fields, like that of a door magnet. Previous research had
> identified only cases in which bacteria as a whole, filled with
> magnetic particles, are being oriented like compass needles for
> swimming in the right direction.
>
> Schulten's team, including doctoral student Thorsten Ritz, found
> theoretical evidence that a biochemical reaction involving
> cryptochromes can be influenced by an Earth-strength magnetic
> field. The computations were based on fundamental physics as
> described by the complex equations of quantum mechanics. The
> National Institutes of Health and the Roy J. Carver Charitable
> Trust funded the work.
>
> Migratory birds and other animals, in many cases, cannot
> distinguish between north and south based on magnetic information
> alone. They can only detect the angle of the magnetic field lines
> with the horizon, which, Schulten said, is explained through
> symmetries in visual modulation patterns.
>
> If radical-pair reactions in cryptochromes were connected by
> photoreception to the vision of animals, the magnetic field would
> modulate visual sensitivity, Schulten theorized. Animals would
> "see" the geomagnetic field by superimposing onto its visual images
> information about the field's direction. Behavioral biologists
> tested Schulten's theory. They found that many magnetic responses
> require light, and that the orientation of some animals was erratic
> when exposed to monochromatic red light. Such findings strengthened
> the theory, Schulten and Ritz said, because radical-pair reactions
> require light above a certain energy threshold.
>
> "The visual modulation patterns that we found show surprising
> agreement," Schulten said. "The hunt for the elusive
> magnetoreceptor is not over, but we have provided a new, promising
> track."
>
> ###
> ______________________________________________________________
>
> [4]Back to EurekAlert!
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> References
>
> 1. http://www.eurekalert.org/cgi/users/toc
> 2. mailto:b-james3 at uiuc.edu
> 3. http://www.uiuc.edu/
> 4. http://www.eurekalert.org/cgi/users/toc
>
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