Despite an established consensus that many forms of life can reliably detect the Earth’s weak magnetic field, it is unclear how many complex organisms sense it [1]. Most prominent mechanistic proposals invoke a quantum-biological model [2], relying on the assumption that an excitonic \u201cradical\u201d electron pair [3] facilitates magnetoreception of the Earth’s field (50 \u03bcT).<\/p>\n
Field-dependent decay products of this spin-crossing reaction are believed to constitute a decoherence channel to a signaling state that discriminates the field angle and inclination, yet essential details of the scheme are lacking. Comprehensive models of requisite activation [4-6], charge separation [7-8], chemical amplification [9-10], anisotropic response [11], coherence-preserving [12] and\/or decoherence-limiting [13] steps are needed. Given the rich complexity of the biological milieu and lacking a consistent in vitro model, mechanistic features must be identified empirically in order to confirm a viable magnetic sense receptor.<\/p>\n
In this seminar lecture, I review features of competing models of cryptochrome-based magnetoreception, in the context of existing theory and experiment. Seminar content will address recent conflicts [14-17] between evidences and conventional model proposals [18-19]. Implications of these conflicts will be explored in terms of an expanded model that involves the amplification of the spin-chemical effect\u2014with an eye toward broad generalization of existing principles [20-23]. We assess criticism of models reliant on quantum entanglement in a dynamic environment at physiological temperature [24-28]. If time permits, we will discuss overall challenges facing a broad class of reaction schemes that depend upon coherent singlet-triplet interconversion to enable magnetoreception. In closing, we will consider how the engineering of biosynthetic systems [29] could enable new technologies with ramifications for metrology [30], magnetogenetics [31], and medicine [32].<\/p>\n
Reference List:<\/p>\n
Johnsen & Lohmann, \u00abMagnetoreception in animals,\u00bb Physics Today 61, 29-35 (2008).<\/p>\n<\/li>\n
Lambert et al., \u00abQuantum biology,\u00bb Nature Physics 9, 10-18 (2013).<\/p>\n<\/li>\n
Rodgers & Hore, \u201cChemical magnetoreception in birds: The radical pair mechanism,\u201d Proceedings of the National Academy of Sciences 106, 353-360 (2009).<\/p>\n<\/li>\n
Nie\u00dfner, Denzau, Peichl, Wiltschko, & Wiltschko, \u201cMagnetoreception: activation of avian cryptochrome 1a in various light conditions,\u201d Journal of Comparative Physiology A 204, 977-984 (2018).<\/p>\n<\/li>\n
Ahmad, \u201cPhotocycle and signaling mechanisms of plant cryptochromes,\u201d Current Opinion in Plant Biology 33, 108-115 (2016).<\/p>\n<\/li>\n
Bouly et al., \u201cCryptochrome Blue Light Photoreceptors Are Activated through Interconversion of Flavin Redox States\u201d Journal of Biological Chemistry 282, 9383\u20139391 (2007).<\/p>\n<\/li>\n
Firmino et al., \u201cQuantum effects in ultrafast electron transfers within cryptochromes,\u201d Physical Chemistry Chemical Physics 18, 21442-21457 (2016).<\/p>\n<\/li>\n
Nohr, \u201cExtended Electron-Transfer in Animal Cryptochromes Mediated by a Tetrad of Aromatic Amino Acids,\u201d Biophysical Journal 111, 301-311 (2016).<\/p>\n<\/li>\n
Kattnig et al., \u00abChemical amplification of magnetic field effects relevant to avian magnetoreception,\u00bb Nature Chemistry 8, 384-391 (2016).<\/p>\n<\/li>\n
Kattnig & Hore, \u201cThe sensitivity of a radical pair compass magnetoreceptor can be significantly amplified by radical scavengers,\u201d Scientific Reports 7, 11640 (2017).<\/p>\n<\/li>\n
Hiscock et al., \u00abThe quantum needle of the avian magnetic compass,\u00bb Proceedings of the National Academy of Sciences113, 4634-4639.<\/p>\n<\/li>\n
Hiscock, \u201cLong-lived Spin Coherence in Radical Pair Compass Magnetoreception,\u201d PhD Thesis, University of Oxford (2018).<\/p>\n<\/li>\n
Kattnig, \u201cRadical-Pair-Based Magnetoreception Amplified by Radical Scavenging: Resilience to Spin Relaxation,\u201d Journal of Physical Chemistry B 121, 10215\u201310227 (2017).<\/p>\n<\/li>\n
Pooam et al., \u201cMagnetic sensitivity mediated by the Arabidopsis blue\u2010light receptor cryptochrome occurs during flavin reoxidation in the dark,\u201d Planta 249, 319-332 (2019).<\/p>\n<\/li>\n
Agliassa, Narayana, Christie, & Maffei, \u201cGeomagnetic field impacts on cryptochrome and phytochrome signaling,\u201d Journal of Photochemistry & Photobiology B, 185 32-40 (2018).<\/p>\n<\/li>\n
Wiltschko, Ahmad, Nie\u00dfner, Gehring, & Wiltschko \u201cLight-dependent magnetoreception in birds: the crucial step occurs in the dark,\u201d Royal Society Interface 13, 20151010 (2016).<\/p>\n<\/li>\n
M\u00fcller & Ahmad, \u201cLight-activated Cryptochrome Reacts with Molecular Oxygen to Form a Flavin\u2013Superoxide Radical Pair Consistent with Magnetoreception,\u201d Journal of Biological Chemistry 286, 21033\u201321040 (2011).<\/p>\n<\/li>\n
Hore & Mouritsen, \u201cThe Radical Pair Mechanism of Magnetoreception,\u201d Annual Review of Biophysics, 45 299-344 (2016).<\/p>\n<\/li>\n
Wiltschko & Wiltschko, \u201cSensing Magnetic Directions in Birds: Radical Pair Processes Involving Cryptochrome,\u201d Biosensors 4, 221-242 (2014).<\/p>\n<\/li>\n
Keens, Bedkihal, & Kattnig, \u201cMagnetosensitivity in Dipolarly Coupled Three-Spin Systems,\u201d Physical Review Letters 121, 096001 (2018)<\/p>\n<\/li>\n
Lindoy & Manolopoulos, \u201cSimple and Accurate Method for Central Spin Problems,\u201d Physical Review Letters 120, 220604 (2018).<\/p>\n<\/li>\n
Lewis, Manolopoulos, & Hore, \u201cAsymmetric recombination and electron spin relaxation in the semiclassical theory of radical pair reactions,\u201d Journal of Chemical Physics 141, 044111 (2014).<\/p>\n<\/li>\n
Manolopoulos & Hore, \u201cAn improved semiclassical theory of radical pair recombination reactions,\u201d Journal of Chemical Physics 139, 124106 (2013).<\/p>\n<\/li>\n
Gauger & Benjamin, \u201cComment on \u2018Quantum Coherence and Sensitivity of Avian Magnetoreception\u2019,\u201d Physical Review Letters 110, 178901 (2013).<\/p>\n<\/li>\n
Pauls, Zhang, Berman, & Kais, \u201cQuantum coherence and entanglement in the avian compass,\u201d Physical Review E 97, 062704 (2013).<\/p>\n<\/li>\n
Hogben, Biskup, & Hore, \u00abEntanglement and Sources of Magnetic Anisotropy in Radical Pair-Based Avian Magnetoreceptors,\u00bb Physical Review Letters 109, 220501 (2012).<\/p>\n<\/li>\n
Bandyopadhyay, Paterek, Kaszlikowski, \u201cQuantum Coherence and Sensitivity of Avian Magnetoreception,\u201d Physical Review Letters 109, 110502 (2012).<\/p>\n<\/li>\n
Mendive-Tapia et al., \u201cMultidimensional Quantum Mechanical Modeling of Electron Transfer and Electronic Coherence in Plant Cryptochromes: The Role of Initial Bath Conditions,\u201d Journal of Physical Chemistry B 122, 126\u2212136 (2017).<\/p>\n<\/li>\n
Bialas et al., \u00abEngineering an Artificial Flavoprotein Magnetosensor,\u00bb Journal of the American Chemical Society 138, 16584-16587 (2016).<\/p>\n<\/li>\n
Imamoglu & Whaley, \u201cPhotoactivated biological processes as quantum measurements,\u201d Physical Review E 91, 022714 (2015).<\/p>\n<\/li>\n
Meister, \u201cPhysical limits to magnetogenetics,\u201d eLife 5, e17210 (2016).<\/p>\n<\/li>\n
Juutilainen, Herrala, Luukkonen, Naarala, & Hore, \u201cMagnetocarcinogenesis: is there a mechanism for carcinogenic effects of weak magnetic fields?\u201d Proceedings of the Royal Society B 285, 20180590 (2018).<\/p>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
Despite an established consensus that many forms of life can reliably detect the Earth’s weak magnetic field, it is unclear how many complex organisms sense it [1]. Most prominent mechanistic proposals invoke a quantum-biological model [2], relying on the assumption that an excitonic \u201cradical\u201d electron pair [3] facilitates magnetoreception of the Earth’s field (50 \u03bcT). […]<\/p>\n","protected":false},"author":20,"featured_media":0,"template":"","class_list":["post-1166","seminar","type-seminar","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/seminar\/1166","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/seminar"}],"about":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/types\/seminar"}],"author":[{"embeddable":true,"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/users\/20"}],"wp:attachment":[{"href":"https:\/\/webs.uab.cat\/giq\/wp-json\/wp\/v2\/media?parent=1166"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}