TY  - JOUR
A1  - Nießner, Christine
A1  - Denzau, Susanne
A1  - Peichl, Leo
A1  - Wiltschko, Wolfgang
A1  - Wiltschko, Roswitha
T1  - Magnetoreception in birds : I. immunohistochemical studies concerning the cryptochrome cycle
T2  - Journal of experimental biology
N2  - Cryptochrome 1a, located in the UV/violet-sensitive cones in the avian retina, is discussed as receptor molecule for the magnetic compass of birds. Our previous immunohistochemical studies of chicken retinae with an antiserum that labelled only activated cryptochrome 1a had shown activation of cryptochrome 1a under 373 nm UV, 424 nm blue, 502 nm turquoise and 565 nm green light. Green light, however, does not allow the first step of photoreduction of oxidized cryptochromes to the semiquinone. As the chickens had been kept under ‘white’ light before, we suggested that there was a supply of the semiquinone present at the beginning of the exposure to green light, which could be further reduced and then re-oxidized. To test this hypothesis, we exposed chickens to various wavelengths (1) for 30 min after being kept in daylight, (2) for 30 min after a 30 min pre-exposure to total darkness, and (3) for 1 h after being kept in daylight. In the first case, we found activated cryptochrome 1a under UV, blue, turquoise and green light; in the second two cases we found activated cryptochrome 1a only under UV to turquoise light, where the complete redox cycle of cryptochrome can run, but not under green light. This observation is in agreement with the hypothesis that activated cryptochrome 1a is found as long as there is some of the semiquinone left, but not when the supply is depleted. It supports the idea that the crucial radical pair for magnetoreception is generated during re-oxidation.
KW  - Magnetic compass
KW  - Cryptochrome 1a
KW  - Flavin cycle
KW  - Photoreduction
KW  - Activated Cry1a
KW  - Radical pair mechanisms
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/42276
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-422768
UR  - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4254396
SN  - 0022-0949
SN  - 1477-9145
N1  - © 2014. Published by The Company of Biologists Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
VL  - 217
IS  - 23
SP  - 4221
EP  - 4224
PB  - Company of Biologists
CY  - Cambridge
ER  -