Department of Physics, University of California, Irvine, CA, USA.
J R Soc Interface. 2010 Apr 6;7 Suppl 2(Suppl 2):S265-71. doi: 10.1098/rsif.2009.0378.focus. Epub 2009 Nov 11.
A proposed mechanism for magnetic compasses in animals is that systems of radical pairs transduce magnetic field information to the nervous system. One can show that perfectly ordered arrays of radical pairs are sensitive to the direction of the external magnetic field and can thus operate, in principle, as a magnetic compass. Here, we investigate how disorder, inherent in biological cells, affects the ability of radical pair systems to provide directional information. We consider biologically inspired geometrical arrangements of ensembles of radical pairs with increasing amounts of disorder and calculate the effect of changing the direction of the external magnetic field on the rate of chemical signal production by radical pair systems. Using a previously established signal transduction model, we estimate the minimum number of receptors necessary to allow for detection of the change in chemical signal owing to changes in magnetic field direction. We quantify the required increase in the number of receptors to compensate for the signal attenuation through increased disorder. We find radical-pair-based compass systems to be relatively robust against disorder, suggesting several scenarios as to how a compass structure can be realized in a biological cell.
一种用于动物的磁罗盘的提出机制是，自由基对系统将磁场信息转换为神经系统。人们可以证明，完全有序的自由基对排列对外部磁场的方向敏感，因此可以在原则上作为磁罗盘运行。在这里，我们研究了生物细胞固有的无序性如何影响自由基对系统提供方向信息的能力。我们考虑了具有不同无序程度的自由基对集合的生物启发几何排列，并计算了改变外部磁场方向对自由基对系统产生化学信号速率的影响。使用先前建立的信号转导模型，我们估计了为了检测由于磁场方向变化而导致的化学信号变化所需的最小受体数量。我们量化了为了补偿通过增加无序而导致的信号衰减所需的受体数量的增加。我们发现基于自由基对的罗盘系统对无序具有相对鲁棒性，这表明在生物细胞中实现罗盘结构的几种情况。
