TY  - JOUR
A1  - Wiltschko, Roswitha
A1  - Ahmad, Margaret
A1  - Nießner, Christine
A1  - Gehring, Dennis
A1  - Wiltschko, Wolfgang
T1  - Light-dependent magnetoreception in birds : the crucial step occurs in the dark
T2  - Interface
N2  - The Radical Pair Model proposes that the avian magnetic compass is based on spin-chemical processes: since the ratio between the two spin states singlet and triplet of radical pairs depends on their alignment in the magnetic field, it can provide information on magnetic directions. Cryptochromes, blue light-absorbing flavoproteins, with flavin adenine dinucleotide as chromophore, are suggested as molecules forming the radical pairs underlying magnetoreception. When activated by light, cryptochromes undergo a redox cycle, in the course of which radical pairs are generated during photo-reduction as well as during light-independent re-oxidation. This raised the question as to which radical pair is crucial for mediating magnetic directions. Here, we present the results from behavioural experiments with intermittent light and magnetic field pulses that clearly show that magnetoreception is possible in the dark interval, pointing to the radical pair formed during flavin re-oxidation. This differs from the mechanism considered for cryptochrome signalling the presence of light and rules out most current models of an avian magnetic compass based on the radical pair generated during photo-reduction. Using the radical pair formed during re-oxidation may represent a specific adaptation of the avian magnetic compass.
KW  - avian magnetic compass
KW  - cryptochrome 1a
KW  - flavin redox cycle
KW  - light-activation
KW  - radical pairs
Y1  - 2016
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/42207
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-422071
UR  - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4892254
SN  - 1742-5662
SN  - 1742-5689
N1  - © 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
VL  - 13
IS  - 118, 20151010
SP  - 1
EP  - 7
PB  - The Royal Society
CY  - London
ER  -