Planaria serve as an intriguing model system wherein the effects of electric and magnetic fields on various biochemical pathways during cell morphogenesis can be studied. Recent experimental observations have demonstrated the non-trivial modulation of reactive oxygen species (ROS) levels by a weak magnetic field (WMF) during planaria regeneration. However, the underlying biophysical mechanism behind this remains elusive. In this work, we investigate the role of the radical pair mechanism (RPM) and attempt to explain the experimental results of the effect of WMFs on ROS modulation during planaria regeneration. We also propose that instead of the flavin adenine dinucleotide-superoxide radical pair (FADH•−O2•−), a non-superoxide-based flavin adenine dinucleotide-tryptophan radical pair (FAD•−−TrpH•+) might be a more suitable radical pair (RP) candidate for the observed ROS modulation. We also investigate the role of chirality-induced spin selectivity on ROS levels by including it in the framework of the RPM. We conclude that the singlet initiated FAD•−−TrpH•+ is a more realistic choice of RP, and hence, superoxide formation might happen later and not during the RP spin dynamics.

中文翻译：

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自由基对机制和手性诱导的自旋选择性在涡虫再生过程中的作用


Planaria 是一个有趣的模型系统，其中可以研究电场和磁场对细胞形态发生过程中各种生化途径的影响。最近的实验观察表明，在涡虫再生过程中，弱磁场 （WMF） 对活性氧 （ROS） 水平的非平凡调制。然而，这背后的潜在生物物理机制仍然难以捉摸。在这项工作中，我们研究了自由基对机制 （RPM） 的作用，并试图解释 WMFs 对涡虫再生过程中 ROS 调节影响的实验结果。我们还提出，非基于超氧化物的黄素腺嘌二核苷酸-色氨酸自由基对 （FAD•−-TrpH•+） 可能是观察到的 ROS 调节的更合适的自由基对 （RP） 候选者。我们还通过将手性诱导的自旋选择性包含在 RPM 框架中来研究手性诱导的自旋选择性对 ROS 水平的作用。我们得出结论，单重态引发的 FAD•−−TrpH•+ 是 RP 的更现实选择，因此，超氧化物的形成可能发生在更晚，而不是在 RP 自旋动力学期间。