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
Contact: Jim Barlow, Life Sciences Editor
University of Illinois at Urbana-Champaign