A model for photoreceptor-based magnetoreception in birds
A model for photoreceptor-based magnetoreception in birds
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DOI：
10.1016/s0006-3495(00)76629-x
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发表时间：
2000-02-01
影响因子：
3.4
通讯作者：
Schulten, K
中科院分区：
文献类型：
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作者：
Ritz, T;Adem, S;Schulten, K
许多种类的动物都有能力感知地磁场，并将其用作定向(指南针)信息的来源。目前尚不清楚这种磁接收是通过哪种生物物理机制实现的。我们研究了磁接收涉及自由基对过程的可能性，该过程由(未配对的)电子和核自旋之间的各向异性超精细耦合所支配。我们将从理论上证明，对于自由基对与磁场的不同排列，地磁场的强场和弱场可以产生显著不同的反应产率。作为磁性感觉器官的模型，我们提出了一个自由基对系统，它是1)在分子底物中定向有序的，2)表现出影响视觉转导途径的反应产率的变化。我们评估了由于地磁场对自由基对系统的影响而产生的三维视觉调制模式。这些模式随方位和磁场强度的变化可以提供鸟类的磁罗盘能力，具有与行为实验中观察到的相同的特征。我们认为最近发现的光感受器隐花色素是磁接收系统的一部分，并建议进行进一步的研究来证明或反驳这一假说。
A large variety of animals has the ability to sense the geomagnetic field and utilize it as a source of directional (compass) information. It is not known by which biophysical mechanism this magnetoreception is achieved. We investigate the possibility that magnetoreception involves radical-pair processes that are governed by anisotropic hyperfine coupling between (unpaired) electron and nuclear spins. We will show theoretically that fields of geomagnetic field strength and weaker can produce significantly different reaction yields for different alignments of the radical pairs with the magnetic field. As a model for a magnetic sensory organ we propose a system of radical pairs being 1) orientationally ordered in a molecular substrate and 2) exhibiting changes in the reaction yields that affect the visual transduction pathway. We evaluate three-dimensional visual modulation patterns that can arise from the influence of the geomagnetic field on radical-pair systems. The variations of these patterns with orientation and field strength can furnish the magnetic compass ability of birds with the same characteristics as observed in behavioral experiments. We propose that the recently discovered photoreceptor cryptochrome is part of the magnetoreception system and suggest further studies to prove or disprove this hypothesis.