Current Biology, Volume 15, Issue 16, 23 August 2005, Pages 1518-1523
Roswitha Wiltschko, Thorsten Ritz, Katrin Stapput, Peter Thalau and
Current Biology, Volume 15, Issue 16, 23 August 2005, Pages 1518-1523
Roswitha Wiltschko, Thorsten Ritz, Katrin Stapput, Peter Thalau and Wolfgang Wiltschko
A model of magnetoreception  proposes that the avian magnetic compass is based on a radical pair mechanism, with photon absorption leading to the formation of radical pairs. Analyzing the predicted light dependency by testing migratory birds under monochromatic lights, we found that the responses of birds change with increasing intensity. The analysis of the orientation of European robins under 502 nm turquoise light revealed two types of responses depending on light intensity: under a quantal flux of 8·1015 quanta m−2 s−1, the birds showed normal migratory orientation in spring as well as in autumn, relying on their inclination compass. Under brighter light of 54·1015 quanta m−2 s−1, however, they showed a “fixed” tendency toward north that did not undergo the seasonal change and proved to be based on magnetic polarity, not involving the inclination compass. When birds were exposed to a weak oscillating field, which specifically interferes with radical pair processes, the inclination compass response was disrupted, whereas the response to magnetic polarity remained unaffected. These findings indicate that the normal inclination compass used for migratory orientation is based on a radical-pair mechanism, whereas the fixed direction represents a novel type of light-dependent orientation based on a mechanism of a different nature.
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Biophysical Journal, Volume 94, Issue 9, 1 May 2008, Pages 3590-3600
Yu Kay Law, Javad Azadi, Carlos E. Crespo-Hernández, Eric Olmon and Bern Kohler
It was recently shown that thymine dimers in the all-thymine oligonucleotide (dT)18 are fully formed in <1ps after ultraviolet exc