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DeOliveira CC, Crane BR. A structural decryption of cryptochromes. Front Chem 2024; 12:1436322. [PMID: 39220829 PMCID: PMC11362059 DOI: 10.3389/fchem.2024.1436322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024] Open
Abstract
Cryptochromes (CRYs), which are signaling proteins related to DNA photolyases, play pivotal roles in sensory responses throughout biology, including growth and development, metabolic regulation, circadian rhythm entrainment and geomagnetic field sensing. This review explores the evolutionary relationships and functional diversity of cryptochromes from the perspective of their molecular structures. In general, CRY biological activities derive from their core structural architecture, which is based on a Photolyase Homology Region (PHR) and a more variable and functionally specific Cryptochrome C-terminal Extension (CCE). The α/β and α-helical domains within the PHR bind FAD, modulate redox reactive residues, accommodate antenna cofactors, recognize small molecules and provide conformationally responsive interaction surfaces for a range of partners. CCEs add structural complexity and divergence, and in doing so, influence photoreceptor reactivity and tailor function. Primary and secondary pockets within the PHR bind myriad moieties and collaborate with the CCEs to tune recognition properties and propagate chemical changes to downstream partners. For some CRYs, changes in homo and hetero-oligomerization couple to light-induced conformational changes, for others, changes in posttranslational modifications couple to cascades of protein interactions with partners and effectors. The structural exploration of cryptochromes underscores how a broad family of signaling proteins with close relationship to light-dependent enzymes achieves a wide range of activities through conservation of key structural and chemical properties upon which function-specific features are elaborated.
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Affiliation(s)
| | - Brian R. Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
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2
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Grüning G, Gerhards L, Wong SY, Kattnig DR, Solov'yov IA. The Effect of Spin Relaxation on Magnetic Compass Sensitivity in ErCry4a. Chemphyschem 2024:e202400129. [PMID: 38668824 DOI: 10.1002/cphc.202400129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/16/2024] [Indexed: 09/04/2024]
Abstract
This study explores the impact of thermal motion on the magnetic compass mechanism in migratory birds, focusing on the radical pair mechanism within cryptochrome photoreceptors. The coherence of radical pairs, crucial for magnetic field inference, is curbed by spin relaxation induced by intra-protein motion. Molecular dynamics simulations, density-functional-theory-based calculations, and spin dynamics calculations were employed, utilizing Bloch-Redfield-Wangsness (BRW) relaxation theory, to investigate compass sensitivity. Previous research hypothesized that European robin's cryptochrome 4a (ErCry4a) optimized intra-protein motion to minimize spin relaxation, enhancing magnetic sensing compared to the plant Arabidopsis thaliana's cryptochrome 1 (AtCry1). Different correlation times of the nuclear hyperfine coupling constants in AtCry1 and ErCry4a were indeed found, leading to distinct radical pair recombination yields in the two species, with ErCry4a showing optimized sensitivity. However, this optimization is likely negligible in realistic spin systems with numerous nuclear spins. Beyond insights in magnetic sensing, the study presents a detailed method employing molecular dynamics simulations to assess for spin relaxation effects on chemical reactions with realistically modelled protein motion, relevant for studying radical pair reactions at finite temperature.
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Affiliation(s)
- Gesa Grüning
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany
| | - Luca Gerhards
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany
| | - Siu Y Wong
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky University Oldenburg, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany
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3
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Liu L, Huang B, Lu Y, Zhao Y, Tang X, Shi Y. Interactions between electromagnetic radiation and biological systems. iScience 2024; 27:109201. [PMID: 38433903 PMCID: PMC10906530 DOI: 10.1016/j.isci.2024.109201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
Even though the bioeffects of electromagnetic radiation (EMR) have been extensively investigated during the past several decades, our understandings of the bioeffects of EMR and the mechanisms of the interactions between the biological systems and the EMRs are still far from satisfactory. In this article, we introduce and summarize the consensus, controversy, limitations, and unsolved issues. The published works have investigated the EMR effects on different biological systems including humans, animals, cells, and biochemical reactions. Alternative methodologies also include dielectric spectroscopy, detection of bioelectromagnetic emissions, and theoretical predictions. In many studies, the thermal effects of the EMR are not properly controlled or considered. The frequency of the EMR investigated is limited to the commonly used bands, particularly the frequencies of the power line and the wireless communications; far fewer studies were performed for other EMR frequencies. In addition, the bioeffects of the complex EM environment were rarely discussed. In summary, our understanding of the bioeffects of the EMR is quite restrictive and further investigations are needed to answer the unsolved questions.
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Affiliation(s)
- Lingyu Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Huang
- Brain Function and Disease Laboratory, Department of Pharmacology, Shantou University Medical College, 22 Xin-Ling Road, Shantou 515041, China
| | - Yingxian Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yanyu Zhao
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Xiaping Tang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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4
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Luo J. Sensitivity enhancement of radical-pair magnetoreceptors as a result of spin decoherence. J Chem Phys 2024; 160:074306. [PMID: 38380753 DOI: 10.1063/5.0182172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Electron spin relaxation is, on many occasions, considered an elephant in the room that challenges the idea of a radical-pair compass, a leading hypothesis for the navigation of migratory avian species. It has been widely recognized that an effective radical-pair magnetoreceptor requires a relaxation time that is long enough for an external magnetic field as weak as the geomagnetic field to significantly modify the coherent spin dynamics. However, previous studies proposed that certain spin relaxation, far quicker than the radical recombination reactions, could enhance, rather than degrade, the directional sensitivity of a radical-pair magnetoreceptor. Here, I investigate relaxation effects on the singlet-triplet interconversion of a model radical pair and find that the enhancement effect originates from population relaxation over a period of several microseconds as a result of efficient spin decoherence. Insights into the truncated spin systems shed light on the physics behind them. I further investigate the possibilities of such enhancement in cryptochrome-based magnetoreception, in which electron hopping takes place between tryptophan residues.
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Affiliation(s)
- Jiate Luo
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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Loewe B, Kozhukhov T, Shendruk TN. Anisotropic run-and-tumble-turn dynamics. SOFT MATTER 2024; 20:1133-1150. [PMID: 38226730 PMCID: PMC10828927 DOI: 10.1039/d3sm00589e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 12/12/2023] [Indexed: 01/17/2024]
Abstract
Run-and-tumble processes successfully model several living systems. While studies have typically focused on particles with isotropic tumbles, recent examples exhibit "tumble-turns", in which particles undergo 90° tumbles and so possess explicitly anisotropic dynamics. We study the consequences of such tumble-turn anisotropicity at both short and long-time scales. We model run-and-tumble-turn particles as self-propelled particles subjected to an angular potential that favors directions of movement parallel to Cartesian axes. Using agent-based simulations, we study the effects of the interplay between rotational diffusion and an aligning potential on the particles' trajectories, which leads to the right-angled turns. We demonstrate that the long-time effect is to alter the tumble-turn time, which governs the long-time dynamics. In particular, when normalized by this timescale, trajectories become independent of the underlying details of the potential. As such, we develop a simplified continuum theory, which quantitatively agrees with agent-based simulations. We find that the purely diffusive hydrodynamic limit still exhibits anisotropic features at intermediate times and conclude that the transition to diffusive dynamics precedes the transition to isotropic dynamics. By considering short-range repulsive and alignment particle-particle interactions, we show how the anisotropic features of a single particle are inherited by the global order of the system. We hope this work will shed light on how active systems can extend local anisotropic properties to macroscopic scales, which might be important in biological processes occurring in anisotropic environments.
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Affiliation(s)
- Benjamin Loewe
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
| | - Timofey Kozhukhov
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
| | - Tyler N Shendruk
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
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Galván I, Hassasfar A, Adams B, Petruccione F. Isotope effects on radical pair performance in cryptochrome: A new hypothesis for the evolution of animal migration: The quantum biology of migration. Bioessays 2024; 46:e2300152. [PMID: 37888800 DOI: 10.1002/bies.202300152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/28/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023]
Abstract
Mechanisms occurring at the atomic level are now known to drive processes essential for life, as revealed by quantum effects on biochemical reactions. Some macroscopic characteristics of organisms may thus show an atomic imprint, which may be transferred across organisms and affect their evolution. This possibility is considered here for the first time, with the aim of elucidating the appearance of an animal innovation with an unclear evolutionary origin: migratory behaviour. This trait may be mediated by a radical pair (RP) mechanism in the retinal flavoprotein cryptochrome, providing essential magnetic orientation for migration. Isotopes may affect the performance of quantum processes through their nuclear spin. Here, we consider a simple model and then apply the standard open quantum system approach to the spin dynamics of cryptochrome RP. We changed the spin quantum number (I) and g-factor of hydrogen and nitrogen isotopes to investigate their effect on RP's yield and magnetic sensitivity. Strong differences arose between isotopes with I = 1 and I = 1/2 in their contribution to cryptochrome magnetic sensitivity, particularly regarding Earth's magnetic field strengths (25-65 µT). In most cases, isotopic substitution improved RP's magnetic sensitivity. Migratory behaviour may thus have been favoured in animals with certain isotopic compositions of cryptochrome.
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Affiliation(s)
- Ismael Galván
- Department of Evolutionary Ecology, National Museum of Natural Sciences, CSIC, Madrid, Spain
| | - Abbas Hassasfar
- Department of Physics, Stellenbosch University, Stellenbosch, South Africa
| | - Betony Adams
- Quantum Research Group, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
- The Guy Foundation, Beaminster, Dorset, UK
| | - Francesco Petruccione
- Department of Physics, Stellenbosch University, Stellenbosch, South Africa
- School for Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
- National Institute for Theoretical and Computational Sciences (NITheCS), Stellenbosch, South Africa
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Thoradit T, Thongyoo K, Kamoltheptawin K, Tunprasert L, El-Esawi MA, Aguida B, Jourdan N, Buddhachat K, Pooam M. Cryptochrome and quantum biology: unraveling the mysteries of plant magnetoreception. FRONTIERS IN PLANT SCIENCE 2023; 14:1266357. [PMID: 37860259 PMCID: PMC10583551 DOI: 10.3389/fpls.2023.1266357] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/14/2023] [Indexed: 10/21/2023]
Abstract
Magnetoreception, the remarkable ability of organisms to perceive and respond to Earth's magnetic field, has captivated scientists for decades, particularly within the field of quantum biology. In the plant science, the exploration of the complicated interplay between quantum phenomena and classical biology in the context of plant magnetoreception has emerged as an attractive area of research. This comprehensive review investigates into three prominent theoretical models: the Radical Pair Mechanism (RPM), the Level Crossing Mechanism (LCM), and the Magnetite-based MagR theory in plants. While examining the advantages, limitations, and challenges associated with each model, this review places a particular weight on the RPM, highlighting its well-established role of cryptochromes and in-vivo experiments on light-independent plant magnetoreception. However, alternative mechanisms such as the LCM and the MagR theory are objectively presented as convincing perspectives that permit further investigation. To shed light on these theoretical frameworks, this review proposes experimental approaches including cutting-edge experimental techniques. By integrating these approaches, a comprehensive understanding of the complex mechanisms driving plant magnetoreception can be achieved, lending support to the fundamental principle in the RPM. In conclusion, this review provides a panoramic overview of plant magnetoreception, highlighting the exciting potential of quantum biology in unraveling the mysteries of magnetoreception. As researchers embark on this captivating scientific journey, the doors to deciphering the diverse mechanisms of magnetoreception in plants stand wide open, offering a profound exploration of nature's adaptations to environmental cues.
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Affiliation(s)
- Thawatchai Thoradit
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Kanjana Thongyoo
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | | | - Lalin Tunprasert
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
- State Key Laboratory for Mechanical Behavior of Materials, School of Material Science and Engineering, Xi’an Jiaotong University, Xi’an, China
| | | | - Blanche Aguida
- UMR CNRS 8256 Adaptation biologique et vieillissement (B2A), Institute of Biology Paris Seine, Sorbonne Université, Paris, France
| | - Nathalie Jourdan
- UMR CNRS 8256 Adaptation biologique et vieillissement (B2A), Institute of Biology Paris Seine, Sorbonne Université, Paris, France
| | - Kittisak Buddhachat
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Marootpong Pooam
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
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Wang Z, Xu Z, Luo Y, Peng S, Song H, Li T, Zheng J, Liu N, Wu S, Zhang J, Zhang L, Hu Y, Liu Y, Lu D, Dai J, Zhang J. Reduced biophotonic activities and spectral blueshift in Alzheimer's disease and vascular dementia models with cognitive impairment. Front Aging Neurosci 2023; 15:1208274. [PMID: 37727319 PMCID: PMC10505668 DOI: 10.3389/fnagi.2023.1208274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/18/2023] [Indexed: 09/21/2023] Open
Abstract
Background Although clinically, Alzheimer's disease (AD) and vascular dementia (VaD) are the two major types of dementia, it is unclear whether the biophotonic activities associated with cognitive impairments in these diseases share common pathological features. Methods We used the ultraweak biophoton imaging system (UBIS) and synaptosomes prepared by modified percoll method to directly evaluate the functional changes in synapses and neural circuits in AD and VaD model animals. Results We found that biophotonic activities induced by glutamate were significantly reduced and spectral blueshifted in synaptosomes and brain slices. These changes could be partially reversed by pre-perfusion of the ifenprodil, a specific antagonist of the GluN2B subunit of N-methyl-D-aspartate receptors (NMDARs). Conclusion Our findings suggest that AD and VaD pathology present similar but complex changes in biophotonic activities and transmission at synapses and neural circuits, implying that communications and information processing of biophotonic signals in the brain are crucial for advanced cognitive functions.
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Affiliation(s)
- Zhuo Wang
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
- College of Life Science, Wuhan Institute for Neuroscience and Neuroengineering, South-Central Minzu University, Wuhan, China
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhipeng Xu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yi Luo
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Sisi Peng
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hao Song
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Tian Li
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jiaxin Zheng
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Na Liu
- College of Life Science, Wuhan Institute for Neuroscience and Neuroengineering, South-Central Minzu University, Wuhan, China
| | - Shenjia Wu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Junxia Zhang
- Academy of Chinese Medical Sciences, Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Lei Zhang
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yuan Hu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yanping Liu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Dongwei Lu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jiapei Dai
- College of Life Science, Wuhan Institute for Neuroscience and Neuroengineering, South-Central Minzu University, Wuhan, China
| | - Junjian Zhang
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
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Luo J. On the anisotropic weak magnetic field effect in radical-pair reactions. J Chem Phys 2023; 158:234302. [PMID: 37318169 DOI: 10.1063/5.0149644] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/30/2023] [Indexed: 06/16/2023] Open
Abstract
For more than 60 years, scientists have been fascinated by the fact that magnetic fields even weaker than internal hyperfine fields can markedly affect spin-selective radical-pair reactions. This weak magnetic field effect has been found to arise from the removal of degeneracies in the zero-field spin Hamiltonian. Here, I investigated the anisotropic effect of a weak magnetic field on a model radical pair with an axially symmetric hyperfine interaction. I found that S-T± and T0-T± interconversions driven by the smaller x and y-components of the hyperfine interaction can be hindered or enhanced by a weak external magnetic field, depending on its direction. Additional isotropically hyperfine-coupled nuclear spins preserve this conclusion, although the S → T± and T0 → T± transitions become asymmetric. These results are supported by simulating reaction yields of a more biologically plausible, flavin-based radical pair.
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Affiliation(s)
- Jiate Luo
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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10
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Yurchenko SB. A systematic approach to brain dynamics: cognitive evolution theory of consciousness. Cogn Neurodyn 2023; 17:575-603. [PMID: 37265655 PMCID: PMC10229528 DOI: 10.1007/s11571-022-09863-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/29/2022] [Accepted: 07/21/2022] [Indexed: 12/18/2022] Open
Abstract
The brain integrates volition, cognition, and consciousness seamlessly over three hierarchical (scale-dependent) levels of neural activity for their emergence: a causal or 'hard' level, a computational (unconscious) or 'soft' level, and a phenomenal (conscious) or 'psyche' level respectively. The cognitive evolution theory (CET) is based on three general prerequisites: physicalism, dynamism, and emergentism, which entail five consequences about the nature of consciousness: discreteness, passivity, uniqueness, integrity, and graduation. CET starts from the assumption that brains should have primarily evolved as volitional subsystems of organisms, not as prediction machines. This emphasizes the dynamical nature of consciousness in terms of critical dynamics to account for metastability, avalanches, and self-organized criticality of brain processes, then coupling it with volition and cognition in a framework unified over the levels. Consciousness emerges near critical points, and unfolds as a discrete stream of momentary states, each volitionally driven from oldest subcortical arousal systems. The stream is the brain's way of making a difference via predictive (Bayesian) processing. Its objective observables could be complexity measures reflecting levels of consciousness and its dynamical coherency to reveal how much knowledge (information gain) the brain acquires over the stream. CET also proposes a quantitative classification of both disorders of consciousness and mental disorders within that unified framework.
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11
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Matysik J, Gerhards L, Theiss T, Timmermann L, Kurle-Tucholski P, Musabirova G, Qin R, Ortmann F, Solov'yov IA, Gulder T. Spin Dynamics of Flavoproteins. Int J Mol Sci 2023; 24:ijms24098218. [PMID: 37175925 PMCID: PMC10179055 DOI: 10.3390/ijms24098218] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
This short review reports the surprising phenomenon of nuclear hyperpolarization occurring in chemical reactions, which is called CIDNP (chemically induced dynamic nuclear polarization) or photo-CIDNP if the chemical reaction is light-driven. The phenomenon occurs in both liquid and solid-state, and electron transfer systems, often carrying flavins as electron acceptors, are involved. Here, we explain the physical and chemical properties of flavins, their occurrence in spin-correlated radical pairs (SCRP) and the possible involvement of flavin-carrying SCRPs in animal magneto-reception at earth's magnetic field.
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Affiliation(s)
- Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Luca Gerhards
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tobias Theiss
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | - Lisa Timmermann
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | | | - Guzel Musabirova
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Ruonan Qin
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Frank Ortmann
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Ilia A Solov'yov
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tanja Gulder
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
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12
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Gerhards L, Nielsen C, Kattnig DR, Hore PJ, Solov'yov IA. Modeling spin relaxation in complex radical systems using MolSpin. J Comput Chem 2023. [PMID: 37186467 DOI: 10.1002/jcc.27120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 05/17/2023]
Abstract
Spin relaxation is an important aspect of the spin dynamics of free radicals and can have a significant impact on the outcome of their spin-selective reactions. Examples range from the use of radicals as spin qubits in quantum information processing to the radical pair reactions in proteins that may allow migratory birds to sense the direction of the Earth's magnetic field. Accurate modeling of spin relaxation, however, is non-trivial. Bloch-Redfield-Wangsness theory derives a quantum mechanical master equation from system-bath interactions in the Markovian limit that provides a comprehensive framework for describing spin relaxation. Unfortunately, the construction of the master equation is system-specific and often resource-heavy. To address this challenge, we introduce a generalized and efficient implementation of BRW theory as a new feature of the spin dynamics toolkit MolSpin which offers an easy-to-use approach for studying systems of reacting radicals of varying complexity.
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Affiliation(s)
- Luca Gerhards
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Claus Nielsen
- Research & Development Department, Unicontrol, Odense, Denmark
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Exeter, UK
| | - P J Hore
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Institut für Physik, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
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13
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Bezchastnov V, Domratcheva T. Quantum-mechanical insights into the anisotropic response of the cryptochrome radical pair to a weak magnetic field. J Chem Phys 2023; 158:034303. [PMID: 36681637 DOI: 10.1063/5.0133943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cryptochrome photoreceptors contain a photochemically generated radical pair, which is thought to mediate sensing of the geomagnetic field direction in many living organisms. To gain insight into the response of the cryptochrome to a weak magnetic field, we have studied the quantum-mechanical hyperfine spin states of the radical pair. We identify quantum states responsible for the precise detection of the magnetic field direction, taking into account the strongly axial hyperfine interactions of each radical in the radical pair. The contribution of these states to the formation of the cryptochrome signaling state sharply increases when the magnetic field becomes orthogonal to the hyperfine axis of either radical. Due to such a response, the radical pair may be able to detect the particular field direction normal to the plane containing the hyperfine axes of the radicals.
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Affiliation(s)
- Victor Bezchastnov
- Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Tatiana Domratcheva
- Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
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14
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Pažėra G, Benjamin P, Mouritsen H, Hore PJ. Isotope Substitution Effects on the Magnetic Compass Properties of Cryptochrome-Based Radical Pairs: A Computational Study. J Phys Chem B 2023; 127:838-845. [PMID: 36669149 PMCID: PMC9900586 DOI: 10.1021/acs.jpcb.2c05335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The biophysical mechanism of the magnetic compass sense of migratory songbirds is thought to rely on the photochemical reactions of flavin-containing radical pairs in cryptochrome proteins located in the birds' eyes. A consequence of this hypothesis is that the effect of the Earth's magnetic field on the quantum yields of reaction products should be sensitive to isotopic substitutions that modify the hyperfine interactions in the radicals. In this report, we use spin dynamics simulations to explore the effects of 1H → 2H, 12C → 13C, and 14N → 15N isotopic substitutions on the functioning of cryptochrome 4a as a magnetic direction sensor. Two main conclusions emerge. (1) Uniform deuteration of the flavin chromophore appears to be the best way to boost the anisotropy of the magnetic field effect and to change its symmetry. (2) 13C substitution of three of the 12 flavin carbons, in particular C4, C4a, and C8α, seems to be the best recipe for attenuating the anisotropy. These predictions should give insight into the factors that control the magnetic sensitivity once spectroscopic techniques are available for measuring magnetic field effects on oriented protein samples.
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Affiliation(s)
| | - Philip Benjamin
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| | - Henrik Mouritsen
- Institut
für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany,Research
Centre for Neurosensory Science, University
of Oldenburg, Oldenburg 26111, Germany
| | - P. J. Hore
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.,
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15
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Pophof B, Henschenmacher B, Kattnig DR, Kuhne J, Vian A, Ziegelberger G. Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report. HEALTH PHYSICS 2023; 124:39-52. [PMID: 36480584 PMCID: PMC9722389 DOI: 10.1097/hp.0000000000001624] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This report summarizes effects of anthropogenic electric, magnetic, and electromagnetic fields in the frequency range from 0 to 100 MHz on flora and fauna, as presented at an international workshop held on 5-7 November in 2019 in Munich, Germany. Such fields may originate from overhead powerlines, earth or sea cables, and from wireless charging systems. Animals and plants react differentially to anthropogenic fields; the mechanisms underlying these responses are still researched actively. Radical pairs and magnetite are discussed mechanisms of magnetoreception in insects, birds, and mammals. Moreover, several insects as well as marine species possess specialized electroreceptors, and behavioral reactions to anthropogenic fields have been reported. Plants react to experimental modifications of their magnetic environment by growth changes. Strong adverse effects of anthropogenic fields have not been described, but knowledge gaps were identified; further studies, aiming at the identification of the interaction mechanisms and the ecological consequences, are recommended.
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Affiliation(s)
- Blanka Pophof
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Bernd Henschenmacher
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Daniel R. Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Jens Kuhne
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Alain Vian
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France
| | - Gunde Ziegelberger
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
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16
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Grüning G, Wong SY, Gerhards L, Schuhmann F, Kattnig DR, Hore PJ, Solov’yov IA. Effects of Dynamical Degrees of Freedom on Magnetic Compass Sensitivity: A Comparison of Plant and Avian Cryptochromes. J Am Chem Soc 2022; 144:22902-22914. [DOI: 10.1021/jacs.2c06233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Affiliation(s)
- Gesa Grüning
- Department of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Street 9-11, 26129 Oldenburg, Germany
| | - Siu Ying Wong
- Department of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Street 9-11, 26129 Oldenburg, Germany
| | - Luca Gerhards
- Department of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Street 9-11, 26129 Oldenburg, Germany
| | - Fabian Schuhmann
- Department of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Street 9-11, 26129 Oldenburg, Germany
| | - Daniel R. Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, U.K
| | - P. J. Hore
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, U.K
| | - Ilia A. Solov’yov
- Department of Physics, Carl von Ossietzky University, Carl-von-Ossietzky-Street 9-11, 26129 Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Institut für Physik, Ammerländer Heerstreet 114-118, 26129 Oldenburg, Germany
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17
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Wave-like patterns in parameter space interpreted as evidence for macroscopic effects resulting from quantum or quantum-like processes in the brain. Sci Rep 2022; 12:18938. [PMID: 36344534 PMCID: PMC9640589 DOI: 10.1038/s41598-022-22661-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Data from eight numerosity estimation experiments reliably exhibit wave-like patterns in plots of the standard deviations of the response times along the abstract parameter of the magnitude of the error in the numerosity estimation. An explanation for this phenomenon is proposed in terms of an analogy between response times and error magnitude on one hand, and energy and position of quantum particles on the other, constructed using an argument for an overlap between the mathematical apparatus describing Hopfield-type neural networks and quantum systems, established by some researchers. Alternative explanations are presented within the traditional explanatory framework of oscillations due to neural firing, involving hypothetical mechanisms for converting oscillation patterns in time to oscillation patterns in the space of an abstract parameter, such as the magnitude of the error during numerosity estimation. The viability of the proposal of causal influences propagating from the microscale of quantum phenomena to the macroscale of human behavior, needed for the first type of explanation, is exemplified by the phenomenon of magnetoreception in some species of birds, which is allegedly quantum in nature.
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18
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Yurchenko SB. From the origins to the stream of consciousness and its neural correlates. Front Integr Neurosci 2022; 16:928978. [PMID: 36407293 PMCID: PMC9672924 DOI: 10.3389/fnint.2022.928978] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 10/12/2022] [Indexed: 09/22/2023] Open
Abstract
There are now dozens of very different theories of consciousness, each somehow contributing to our understanding of its nature. The science of consciousness needs therefore not new theories but a general framework integrating insights from those, yet not making it a still-born "Frankenstein" theory. First, the framework must operate explicitly on the stream of consciousness, not on its static description. Second, this dynamical account must also be put on the evolutionary timeline to explain the origins of consciousness. The Cognitive Evolution Theory (CET), outlined here, proposes such a framework. This starts with the assumption that brains have primarily evolved as volitional subsystems of organisms, inherited from primitive (fast and random) reflexes of simplest neural networks, only then resembling error-minimizing prediction machines. CET adopts the tools of critical dynamics to account for metastability, scale-free avalanches, and self-organization which are all intrinsic to brain dynamics. This formalizes the stream of consciousness as a discrete (transitive, irreflexive) chain of momentary states derived from critical brain dynamics at points of phase transitions and mapped then onto a state space as neural correlates of a particular conscious state. The continuous/discrete dichotomy appears naturally between the brain dynamics at the causal level and conscious states at the phenomenal level, each volitionally triggered from arousal centers of the brainstem and cognitively modulated by thalamocortical systems. Their objective observables can be entropy-based complexity measures, reflecting the transient level or quantity of consciousness at that moment.
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19
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Feng J, Song B, Zhang Y. Semantic parsing of the life process by quantum biology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 175:79-89. [PMID: 36126802 DOI: 10.1016/j.pbiomolbio.2022.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/23/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
A fact that an ever-increasingly number of research attention has focused on quantum biology demonstrates that it is, by no means, new to works in physic and mathematics, but to molecular biologists, geneticists, and biochemists. This is owing to that quantum biology serves as a distinctive discipline, by using quantum theory to study life sciences in combination with physics, mechanics, mathematics, statistics, and modern biology. Notably, quantum mechanics and its fundamental principles have been employed to clarify complex biological processes and molecular homeostasis within the organic life. Consequently, using the principles of quantum mechanics to study dynamic changes and energy transfer of molecules at the quantum level in biology has been accepted as an unusually distinguishable way to a better explanation of many phenomena in life. It is plausible that a clear conceptual quantum theoretical event is also considered to generally occur for short-term picoseconds or femtoseconds on microscopic nano- and subnanometer scales in biology and biosciences. For instance, photosynthesis, enzyme -catalyzed reactions, magnetic perception, the capture of smell and vision, DNA fragmentation, cellular breathing, mitochondrial processing, as well as brain thinking and consciousness, are all manifested within quantum superposition, quantum coherence, quantum entanglement, quantum tunneling, and other effects. In this mini-review, we describe the recent progress in quantum biology, with a promising direction for further insights into this field.
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Affiliation(s)
- Jing Feng
- Bioengineering College and Graduate School, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing, 400044, China; Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing, 402260, China; The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering & Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing, 400044, China
| | - Bo Song
- School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, No. 580 Jungong Road, Yangpu District, Shanghai, 200093, China
| | - Yiguo Zhang
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, No. 725 Jiangzhou Avenue, Dingshan Street, Jiangjin District, Chongqing, 402260, China; The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering & Faculty of Medical Sciences, Chongqing University, No. 174 Shazheng Street, Shapingba District, Chongqing, 400044, China.
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20
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Ramsay J, Kattnig DR. Radical triads, not pairs, may explain effects of hypomagnetic fields on neurogenesis. PLoS Comput Biol 2022; 18:e1010519. [PMID: 36108063 PMCID: PMC9514667 DOI: 10.1371/journal.pcbi.1010519] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/27/2022] [Accepted: 08/27/2022] [Indexed: 12/03/2022] Open
Abstract
Adult hippocampal neurogenesis and hippocampus-dependent cognition in mice have been found to be adversely affected by hypomagnetic field exposure. The effect concurred with a reduction of reactive oxygen species in the absence of the geomagnetic field. A recent theoretical study suggests a mechanistic interpretation of this phenomenon in the framework of the Radical Pair Mechanism. According to this model, a flavin-superoxide radical pair, born in the singlet spin configuration, undergoes magnetic field-dependent spin dynamics such that the pair's recombination is enhanced as the applied magnetic field is reduced. This model has two ostensible weaknesses: a) the assumption of a singlet initial state is irreconcilable with known reaction pathways generating such radical pairs, and b) the model neglects the swift spin relaxation of free superoxide, which abolishes any magnetic sensitivity in geomagnetic/hypomagnetic fields. We here suggest that a model based on a radical triad and the assumption of a secondary radical scavenging reaction can, in principle, explain the phenomenon without unnatural assumptions, thus providing a coherent explanation of hypomagnetic field effects in biology.
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Affiliation(s)
- Jess Ramsay
- Living Systems Institute and Department of Physics, University of Exeter, Exeter, Devon, United Kingdom
| | - Daniel R. Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Exeter, Devon, United Kingdom
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21
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Zadeh-Haghighi H, Simon C. Magnetic field effects in biology from the perspective of the radical pair mechanism. J R Soc Interface 2022; 19:20220325. [PMID: 35919980 PMCID: PMC9346374 DOI: 10.1098/rsif.2022.0325] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/14/2022] [Indexed: 04/07/2023] Open
Abstract
Hundreds of studies have found that weak magnetic fields can significantly influence various biological systems. However, the underlying mechanisms behind these phenomena remain elusive. Remarkably, the magnetic energies implicated in these effects are much smaller than thermal energies. Here, we review these observations, and we suggest an explanation based on the radical pair mechanism, which involves the quantum dynamics of the electron and nuclear spins of transient radical molecules. While the radical pair mechanism has been studied in detail in the context of avian magnetoreception, the studies reviewed here show that magnetosensitivity is widespread throughout biology. We review magnetic field effects on various physiological functions, discussing static, hypomagnetic and oscillating magnetic fields, as well as isotope effects. We then review the radical pair mechanism as a potential unifying model for the described magnetic field effects, and we discuss plausible candidate molecules for the radical pairs. We review recent studies proposing that the radical pair mechanism provides explanations for isotope effects in xenon anaesthesia and lithium treatment of hyperactivity, magnetic field effects on the circadian clock, and hypomagnetic field effects on neurogenesis and microtubule assembly. We conclude by discussing future lines of investigation in this exciting new area of quantum biology.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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22
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Mazzoccoli G. Chronobiology Meets Quantum Biology: A New Paradigm Overlooking the Horizon? Front Physiol 2022; 13:892582. [PMID: 35874510 PMCID: PMC9296773 DOI: 10.3389/fphys.2022.892582] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Biological processes and physiological functions in living beings are featured by oscillations with a period of about 24 h (circadian) or cycle at the second and third harmonic (ultradian) of the basic frequency, driven by the biological clock. This molecular mechanism, common to all kingdoms of life, comprising animals, plants, fungi, bacteria, and protists, represents an undoubted adaptive advantage allowing anticipation of predictable changes in the environmental niche or of the interior milieu. Biological rhythms are the field of study of Chronobiology. In the last decade, growing evidence hints that molecular platforms holding up non-trivial quantum phenomena, including entanglement, coherence, superposition and tunnelling, bona fide evolved in biosystems. Quantum effects have been mainly implicated in processes related to electromagnetic radiation in the spectrum of visible light and ultraviolet rays, such as photosynthesis, photoreception, magnetoreception, DNA mutation, and not light related such as mitochondrial respiration and enzymatic activity. Quantum effects in biological systems are the field of study of Quantum Biology. Rhythmic changes at the level of gene expression, as well as protein quantity and subcellular distribution, confer temporal features to the molecular platform hosting electrochemical processes and non-trivial quantum phenomena. Precisely, a huge amount of molecules plying scaffold to quantum effects show rhythmic level fluctuations and this biophysical model implies that timescales of biomolecular dynamics could impinge on quantum mechanics biofunctional role. The study of quantum phenomena in biological cycles proposes a profitable “entanglement” between the areas of interest of these seemingly distant scientific disciplines to enlighten functional roles for quantum effects in rhythmic biosystems.
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23
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Deviers J, Cailliez F, Gutiérrez BZ, Kattnig DR, de la Lande A. Ab initio derivation of flavin hyperfine interactions for the protein magnetosensor cryptochrome. Phys Chem Chem Phys 2022; 24:16784-16798. [PMID: 35775941 DOI: 10.1039/d1cp05804e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The radicals derived from flavin adenine dinucleotide (FAD) are a corner stone of recent hypotheses about magnetoreception, including the compass of migratory songbirds. These models attribute a magnetic sense to coherent spin dynamics in radical pairs within the flavo-protein cryptochrome. The primary determinant of sensitivity and directionality of this process are the hyperfine interactions of the involved radicals. Here, we present a comprehensive computational study of the hyperfine couplings in the protonated and unprotonated FAD radicals in cryptochrome 4 from C. livia. We combine long (800 ns) molecular dynamics trajectories to accurate quantum chemistry calculations. Hyperfine parameters are derived using auxiliary density functional theory applied to cluster and hybrid QM/MM (Quantum Mechanics/Molecular Mechanics) models comprising the FAD and its significant surrounding environment, as determined by a detailed sensitivity analysis. Thanks to this protocol we elucidate the sensitivity of the hyperfine interaction parameters to structural fluctuations and the polarisation effect of the protein environment. We find that the ensemble-averaged hyperfine interactions are predominantly governed by thermally induced geometric distortions of the flavin. We discuss our results in view of the expected performance of these radicals as part of a magnetoreceptor. Our data could be used to parametrize spin Hamiltonians including not only average values but also standard deviations.
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Affiliation(s)
- Jean Deviers
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, UK.,Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France.
| | - Fabien Cailliez
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France.
| | - Bernardo Zúñiga Gutiérrez
- Departamento de Química, Universidad de Guadalajara, Blvd. Marcelino García Barragán 1421, C. P. 44430, Guadalajara Jal, Mexico
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, UK
| | - Aurélien de la Lande
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France.
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24
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Chetverikova R, Dautaj G, Schwigon L, Dedek K, Mouritsen H. Double cones in the avian retina form an oriented mosaic which might facilitate magnetoreception and/or polarized light sensing. J R Soc Interface 2022; 19:20210877. [PMID: 35414212 PMCID: PMC9006000 DOI: 10.1098/rsif.2021.0877] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To navigate between breeding and wintering grounds, night-migratory songbirds are aided by a light-dependent magnetic compass sense and maybe also by polarized light vision. Although the underlying mechanisms for magnetoreception and polarized light sensing remain unclear, double cone photoreceptors in the avian retina have been suggested to represent the primary sensory cells. To use these senses, birds must be able to separate the directional information from the Earth's magnetic field and/or light polarization from variations in light intensity. Theoretical considerations suggest that this could be best achieved if neighbouring double cones were oriented in an ordered pattern. Therefore, we investigate the orientation patterns of double cones in European robins (Erithacus rubecula) and domestic chickens (Gallus gallus domesticus). We used whole-mounted retinas labelled with double cone markers to quantify the orientations of individual double cones in relation to their nearest neighbours. In both species, our data show that the double cone array is highly ordered: the angles between neighbouring double cones were more likely to be 90°/-90° in the central retina and 180°/0° in the peripheral retina, respectively. The observed regularity in double cone orientation could aid the cells' putative function in light-dependent magnetoreception and/or polarized light sensing.
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Affiliation(s)
- Raisa Chetverikova
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
| | - Glen Dautaj
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
| | - Leonard Schwigon
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
| | - Karin Dedek
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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25
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Smith LD, Deviers J, Kattnig DR. Observations about utilitarian coherence in the avian compass. Sci Rep 2022; 12:6011. [PMID: 35397661 PMCID: PMC8994785 DOI: 10.1038/s41598-022-09901-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022] Open
Abstract
It is hypothesised that the avian compass relies on spin dynamics in a recombining radical pair. Quantum coherence has been suggested as a resource to this process that nature may utilise to achieve increased compass sensitivity. To date, the true functional role of coherence in these natural systems has remained speculative, lacking insights from sufficiently complex models. Here, we investigate realistically large radical pair models with up to 21 nuclear spins, inspired by the putative magnetosensory protein cryptochrome. By varying relative radical orientations, we reveal correlations of several coherence measures with compass fidelity. Whilst electronic coherence is found to be an ineffective predictor of compass sensitivity, a robust correlation of compass sensitivity and a global coherence measure is established. The results demonstrate the importance of realistic models, and appropriate choice of coherence measure, in elucidating the quantum nature of the avian compass.
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Affiliation(s)
- Luke D Smith
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Jean Deviers
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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26
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Deviers J, Cailliez F, de la Lande A, Kattnig DR. Anisotropic magnetic field effects in the re-oxidation of cryptochrome in the presence of scavenger radicals. J Chem Phys 2022; 156:025101. [PMID: 35032990 DOI: 10.1063/5.0078115] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The avian compass and many other of nature's magnetoreceptive traits are widely ascribed to the protein cryptochrome. There, magnetosensitivity is thought to emerge as the spin dynamics of radicals in the applied magnetic field enters in competition with their recombination. The first and dominant model makes use of a radical pair. However, recent studies have suggested that magnetosensitivity could be markedly enhanced for a radical triad, the primary radical pair of which undergoes a spin-selective recombination reaction with a third radical. Here, we test the practicality of this supposition for the reoxidation reaction of the reduced FAD cofactor in cryptochrome, which has been implicated with light-independent magnetoreception but appears irreconcilable with the classical radical pair mechanism (RPM). Based on the available realistic cryptochrome structures, we predict the magnetosensitivity of radical triad systems comprising the flavin semiquinone, the superoxide, and a tyrosine or ascorbyl scavenger radical. We consider many hyperfine-coupled nuclear spins, the relative orientation and placement of the radicals, their coupling by the electron-electron dipolar interaction, and spin relaxation in the superoxide radical in the limit of instantaneous decoherence, which have not been comprehensively considered before. We demonstrate that these systems can provide superior magnetosensitivity under realistic conditions, with implications for dark-state cryptochrome magnetoreception and other biological magneto- and isotope-sensitive radical recombination reactions.
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Affiliation(s)
- Jean Deviers
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
| | - Fabien Cailliez
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), 15 avenue Jean Perrin, 91405 Orsay, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), 15 avenue Jean Perrin, 91405 Orsay, France
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
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27
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Cellini A, Shankar MK, Wahlgren WY, Nimmrich A, Furrer A, James D, Wranik M, Aumonier S, Beale EV, Dworkowski F, Standfuss J, Weinert T, Westenhoff S. Structural basis of the radical pair state in photolyases and cryptochromes. Chem Commun (Camb) 2022; 58:4889-4892. [PMID: 35352724 PMCID: PMC9008703 DOI: 10.1039/d2cc00376g] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the structure of a photoactivated animal (6-4) photolyase in its radical pair state, captured by serial crystallography. We observe how a conserved asparigine moves towards the semiquinone FAD chromophore and stabilizes it by hydrogen bonding. Several amino acids around the final tryptophan radical rearrange, opening it up to the solvent. The structure explains how the protein environment stabilizes the radical pair state, which is crucial for function of (6-4) photolyases and cryptochromes. The structural response of the drosophila (6-4) photolyase to photoinduced electron transfer along a chain of tryptophans is revealed using a serial crystallographic snapshot of the protein in its radical pair state.![]()
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Affiliation(s)
- Andrea Cellini
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
| | - Madan Kumar Shankar
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
| | - Weixiao Yuan Wahlgren
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
| | - Amke Nimmrich
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
| | - Antonia Furrer
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Daniel James
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Maximilian Wranik
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Sylvain Aumonier
- Photon Science Division - Laboratory for Macromolecules and Bioimaging (LSB), Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Emma V Beale
- Photon Science Division - Laboratory for Synchrotron Radiation and Femtochemistry (LSF), Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Florian Dworkowski
- Photon Science Division - Laboratory for Macromolecules and Bioimaging (LSB), Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Jörg Standfuss
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Tobias Weinert
- Division of Biology and Chemistry-Laboratory for Biomolecular Research, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Sebastian Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
- Department of Chemistry-BMC, University of Uppsala, Husargatan 3, 75237 Uppsala, Sweden
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28
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Babcock N, Kattnig DR. Radical Scavenging Could Answer the Challenge Posed by Electron-Electron Dipolar Interactions in the Cryptochrome Compass Model. JACS AU 2021; 1:2033-2046. [PMID: 34841416 PMCID: PMC8611662 DOI: 10.1021/jacsau.1c00332] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Many birds are endowed with a visual magnetic sense that may exploit magnetosensitive radical recombination processes in the protein cryptochrome. In this widely accepted but unproven model, geomagnetic sensitivity is suggested to arise from variations in the recombination rate of a pair of radicals, whose unpaired electron spins undergo coherent singlet-triplet interconversion in the geomagnetic field by coupling to nuclear spins via hyperfine interactions. However, simulations of this conventional radical pair mechanism (RPM) predicted only tiny magnetosensitivities for realistic conditions because the RPM's directional sensitivity is strongly suppressed by the intrinsic electron-electron dipolar (EED) interactions, casting doubt on its viability as a magnetic sensor. We show how this RPM-suppression problem is overcome in a three-radical system in which a third "scavenger" radical reacts with one member of the primary pair. We use this finding to predict substantial magnetic field effects that exceed those of the RPM in the presence of EED interactions in animal cryptochromes.
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Affiliation(s)
- Nathan
Sean Babcock
- Quantum
Biology Laboratory, Howard University, 2400 Sixth Street NW, Washington District of Columbia, 20059, United States of America
- Living
Systems Institute and Department of Physics University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Daniel R. Kattnig
- Living
Systems Institute and Department of Physics University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
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29
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Kumar J, Malik S, Bhardwaj SK, Rani S. Impact of Light at Night Is Phase Dependent: A Study on Migratory Redheaded Bunting (Emberiza bruniceps). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.751072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Artificial light at night (LAN) alters the physiology and behavior of an organism; however, very little is known about phase-dependent effects of LAN, particularly, in night migratory songbirds. Therefore, in this study, we investigated whether the effects of LAN on daily activity and photoperiodic responses in the Palearctic Indian migratory songbird, redheaded buntings (Emberiza bruniceps), is dependent on the different phases of the night. Male buntings maintained under short photoperiod (8L:16D; L = 100 lux, D < 0.1 lux) in individual activity cages were exposed to LAN (2 lux) for 6 weeks either in 4 h bin given at the different phases of 16 h night (early, mid, or late at ZT 08–12, ZT 14–18, or ZT 20–24, respectively; n = 9 each group) or throughout 16 h night (all night light, n = 6, ZT 08–24, the time of lights ON was considered as Zeitgeber time 0, ZT 0). A group (n = 6) with no LAN served as control. The results showed that LAN at the different phases of night induced differential effects as shown by an intense activity during the night, altered melatonin and temperature rhythms, and showed an increase in body mass and body fattening, food intake, and gonadal size. Midnight light exposure has a greater impact on migration and reproduction linked phenotypes, which is similar to the ones that received light throughout the night. The highlights of this study are that (i) LAN impacts day-night activity behavior, (ii) its continuity with the day alters the perception of day length, (iii) birds showed differential sensitivity to LAN in a phase-dependent manner, (iv) the direction of placing LAN affects the daily responses, e.g., LAN in the early night was “accepted” as extended dusk but the late night was considered as early dawn, and (v) midnight LAN was most effective and induced similar responses as continuous LAN. Overall, LAN induces long day responses in short days and shows differential sensitivity of the different phases of the night toward the light. This information may be valuable in adopting a part-night lighting approach to help reduce the physiological burden, such as early migration and reproduction, of artificial lighting on the nocturnal migrants.
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30
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Einwich A, Seth PK, Bartölke R, Bolte P, Feederle R, Dedek K, Mouritsen H. Localisation of cryptochrome 2 in the avian retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:69-81. [PMID: 34677638 PMCID: PMC8918457 DOI: 10.1007/s00359-021-01506-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022]
Abstract
Cryptochromes are photolyase-related blue-light receptors acting as core components of the mammalian circadian clock in the cell nuclei. One or more members of the cryptochrome protein family are also assumed to play a role in avian magnetoreception, but the primary sensory molecule in the retina of migratory birds that mediates light-dependent magnetic compass orientation has still not been identified. The mRNA of cryptochrome 2 (Cry2) has been reported to be located in the cell nuclei of the retina, but Cry2 localisation has not yet been demonstrated at the protein level. Here, we provide evidence that Cry2 protein is located in the photoreceptor inner segments, the outer nuclear layer, the inner nuclear layer and the ganglion cell layer in the retina of night-migratory European robins, homing pigeons and domestic chickens. At the subcellular level, we find Cry2 both in the cytoplasm and the nucleus of cells residing in these layers. This broad nucleic expression rather points to a role for avian Cry2 in the circadian clock and is consistent with a function as a transcription factor, analogous to mammalian Cry2, and speaks against an involvement in magnetoreception.
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Affiliation(s)
- Angelika Einwich
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Pranav Kumar Seth
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Rabea Bartölke
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Petra Bolte
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Regina Feederle
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Neuherberg, Germany
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
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31
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Gao Y, Wen P, Cardé RT, Xu H, Huang Q. In addition to cryptochrome 2, magnetic particles with olfactory co-receptor are important for magnetic orientation in termites. Commun Biol 2021; 4:1121. [PMID: 34556782 PMCID: PMC8460727 DOI: 10.1038/s42003-021-02661-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/08/2021] [Indexed: 12/02/2022] Open
Abstract
The volatile trail pheromone is an ephemeral chemical cue, whereas the geomagnetic field (GMF) provides a stable positional reference. However, it is unclear whether and how the cryptic termites perceive the GMF for orientation in light or darkness until now. Here, we found that the two termite species, Reticulitermes chinensis and Odontotermes formosanus, use the GMF for orientation. Our silencing cryptochrome 2 (Cry2) impaired magnetic orientation in white light but had no significant impact in complete darkness, suggesting that Cry2 can mediate magnetic orientation in termites only under light. Coincidentally, the presence of magnetic particles enabled the magnetic orientation of termites in darkness. When knock-downing the olfactory co-receptor (Orco) to exclude the effect of trail pheromone, unexpectedly, we found that the Orco participated in termite magnetic orientation under both light and darkness. Our findings revealed a novel magnetoreception model depending on the joint action of radical pair, magnetic particle, and olfactory co-receptor. Gao et al. analyze the role of magnetoreceptor candidates cryptochrome 2 (Cry2), magnetic particles and olfactory coreceptor (Orco) in magnetic orientation in two termite species. They report that termites use Cry2 for directional preference in white light, magnetic particles in darkness, and Orco participates in termite magnetic orientation under both light and darkness.
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Affiliation(s)
- Yongyong Gao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Ping Wen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan Province, 650223, China
| | - Ring T Cardé
- Department of Entomology, University of California Riverside, Riverside, CA, 92521, USA
| | - Huan Xu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Qiuying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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32
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Hermsmeier R, Kłos J, Kotochigova S, Tscherbul TV. Quantum Spin State Selectivity and Magnetic Tuning of Ultracold Chemical Reactions of Triplet Alkali-Metal Dimers with Alkali-Metal Atoms. PHYSICAL REVIEW LETTERS 2021; 127:103402. [PMID: 34533330 DOI: 10.1103/physrevlett.127.103402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/29/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate that it is possible to efficiently control ultracold chemical reactions of alkali-metal atoms colliding with open-shell alkali-metal dimers in their metastable triplet states by choosing the internal hyperfine and rovibrational states of the reactants as well as by inducing magnetic Feshbach resonances with an external magnetic field. We base these conclusions on coupled-channel statistical calculations that include the effects of hyperfine contact and magnetic-field-induced Zeeman interactions on ultracold chemical reactions of hyperfine-resolved ground-state Na and the triplet NaLi(a^{3}Σ^{+}) producing singlet Na_{2}(^{1}Σ_{g}^{+}) and a Li atom. We find that the reaction rates are sensitive to the initial hyperfine states of the reactants. The chemical reaction of fully spin-polarized, high-spin states of rotationless NaLi(a^{3}Σ^{+},v=0,N=0) molecules with fully spin-polarized Na is suppressed by a factor of 10-100 compared to that of unpolarized reactants. We interpret these findings within the adiabatic state model, which treats the reaction as a sequence of nonadiabatic transitions between the initial nonreactive high-spin state and the final low-spin states of the reaction complex. In addition, we show that magnetic Feshbach resonances can similarly change reaction rate coefficients by several orders of magnitude. Some of these resonances are due to resonant trimer bound states dissociating to the N=2 rotational state of NaLi(a^{3}Σ^{+},v=0) and would thus exist in systems without hyperfine interactions.
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Affiliation(s)
| | - Jacek Kłos
- Department of Physics, Joint Quantum Institute, University of Maryland College Park, College Park, Maryland 20742, USA
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | | | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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33
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Low magnetic field effects on a photoinduced electron transfer reaction in an ionic liquid. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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34
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Jain R, Poonia VS, Saha K, Saha D, Ganguly S. The avian compass can be sensitive even without sustained electron spin coherence. Proc Math Phys Eng Sci 2021. [DOI: 10.1098/rspa.2020.0778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theoretical studies indicating the presence of long-lived coherence in the radical pair system have engendered questions about its utilitarian role in the avian compass. In this paper, we investigate the role of electron spin coherence in a multinuclear radical pair system including its impact on compass sensitivity. We find that sustenance of long-lived electron spin coherence is unlikely in a multinuclear hyperfine environment. After probing the role of the hyperfine interactions in the compass, we affirm the hyperfine anisotropy to be an essential parameter for the necessary sensitivity required for the compass action. Thereby, we identify a parameter regime where the compass would exhibit good sensitivity even without sustained electron spin coherence.
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Affiliation(s)
- Rakshit Jain
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14850, USA
| | - Vishvendra S. Poonia
- Department of Electronics and Communication Engineering, Indian Institute of Technology Roorkee, India
| | - Kasturi Saha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Dipankar Saha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Swaroop Ganguly
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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35
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Dyer AG, Greentree AD, Garcia JE, Dyer EL, Howard SR, Barth FG. Einstein, von Frisch and the honeybee: a historical letter comes to light. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:449-456. [PMID: 33970340 PMCID: PMC8222030 DOI: 10.1007/s00359-021-01490-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 12/04/2022]
Abstract
The work of the Nobel Laureate Karl von Frisch, the founder of this journal, was seminal in many ways. He established the honeybee as a key animal model for experimental behavioural studies on sensory perception, learning and memory, and first correctly interpreted its famous dance communication. Here, we report on a previously unknown letter by the Physicist and Nobel Laureate Albert Einstein that was written in October 1949. It briefly addresses the work of von Frisch and also queries how understanding animal perception and navigation may lead to innovations in physics. We discuss records proving that Einstein and von Frisch met in April 1949 when von Frisch visited the USA to present a lecture on bees at Princeton University. In the historical context of Einstein’s theories and thought experiments, we discuss some more recent discoveries of animal sensory capabilities alien to us humans and potentially valuable for bio-inspired design improvements. We also address the orientation of animals like migratory birds mentioned by Einstein 70 years ago, which pushes the boundaries of our understanding nature, both its biology and physics.
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Affiliation(s)
- Adrian G Dyer
- School of Media and Communication, RMIT University, Melbourne, VIC, 3001, Australia
- Department of Physiology, Monash University, Clayton, VIC, 3800, Australia
| | - Andrew D Greentree
- ARC Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Jair E Garcia
- School of Media and Communication, RMIT University, Melbourne, VIC, 3001, Australia
| | - Elinya L Dyer
- Department of Computer Science and Software Engineering, Swinburne University of Technology, Hawthorn, VIC, 3122, Australia
| | - Scarlett R Howard
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, VIC, 3217, Australia
| | - Friedrich G Barth
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of Vienna, Althanstr.14, 1090, Vienna, Austria.
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36
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Smith J, Zadeh Haghighi H, Salahub D, Simon C. Radical pairs may play a role in xenon-induced general anesthesia. Sci Rep 2021; 11:6287. [PMID: 33737599 PMCID: PMC7973516 DOI: 10.1038/s41598-021-85673-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
Understanding the mechanisms underlying general anesthesia would be a key step towards understanding consciousness. The process of xenon-induced general anesthesia has been shown to involve electron transfer, and the potency of xenon as a general anesthetic exhibits isotopic dependence. We propose that these observations can be explained by a mechanism in which the xenon nuclear spin influences the recombination dynamics of a naturally occurring radical pair of electrons. We develop a simple model inspired by the body of work on the radical-pair mechanism in cryptochrome in the context of avian magnetoreception, and we show that our model can reproduce the observed isotopic dependence of the general anesthetic potency of xenon in mice. Our results are consistent with the idea that radical pairs of electrons with entangled spins could be important for consciousness.
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Affiliation(s)
- Jordan Smith
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Hadi Zadeh Haghighi
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Dennis Salahub
- Department of Chemistry, Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, Centre for Molecular Simulation, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Christoph Simon
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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37
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Keens RH, Sampson C, Kattnig DR. How symmetry-breaking can amplify the magnetosensitivity of dipolarly coupled n-radical systems. J Chem Phys 2021; 154:094101. [PMID: 33685169 DOI: 10.1063/5.0041552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In systems of more than two reactive radicals, the radical recombination probability can be magnetosensitive due to the mere effect of the inter-radical electron-electron dipolar coupling. Here, we demonstrate that this principle, previously established for three-radical systems, generalizes to n-radical systems. We focus on radical systems in the plane and explore the effects of symmetry, in particular its absence, on the associated magnetic field effects of the recombination yield. We show, by considering regular configurations and slightly distorted geometries, that the breaking of geometric symmetry can lead to an enhancement of the magnetosensitivity of these structures. Furthermore, we demonstrate the presence of effects at low-field that are abolished in the highly symmetric case. This could be important to the understanding of the behavior of radicals in biological environments in the presence of weak magnetic fields comparable to the Earth's, as well as the construction of high-precision quantum sensing devices.
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Affiliation(s)
- Robert H Keens
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, United Kingdom
| | - Chris Sampson
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, United Kingdom
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, United Kingdom
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38
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Bolte P, Einwich A, Seth PK, Chetverikova R, Heyers D, Wojahn I, Janssen-Bienhold U, Feederle R, Hore P, Dedek K, Mouritsen H. Cryptochrome 1a localisation in light- and dark-adapted retinae of several migratory and non-migratory bird species: no signs of light-dependent activation. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2020.1870571] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Petra Bolte
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Angelika Einwich
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Pranav K. Seth
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Raisa Chetverikova
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Dominik Heyers
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Irina Wojahn
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Department of Neuroscience, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Peter Hore
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
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39
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Electronic spin separation induced by nuclear motion near conical intersections. Nat Commun 2021; 12:700. [PMID: 33514700 PMCID: PMC7846775 DOI: 10.1038/s41467-020-20831-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/14/2020] [Indexed: 11/23/2022] Open
Abstract
Though the concept of Berry force was proposed thirty years ago, little is known about the practical consequences of this force as far as chemical dynamics are concerned. Here, we report that when molecular dynamics pass near a conical intersection, a massive Berry force can appear as a result of even a small amount of spin-orbit coupling (<10−3 eV), and this Berry force can in turn dramatically change pathway selection. In particular, for a simple radical reaction with two outgoing reaction channels, an exact quantum scattering solution in two dimensions shows that the presence of a significant Berry force can sometimes lead to spin selectivity as large as 100%. Thus, this article opens the door for organic chemists to start designing spintronic devices that use nuclear motion and conical intersections (combined with standard spin-orbit coupling) in order to achieve spin selection. Vice versa, for physical chemists, this article also emphasizes that future semiclassical simulations of intersystem crossing (which have heretofore ignored Berry force) should be corrected to account for the spin polarization that inevitably arises when dynamics pass near conical intersections. Spin polarization is at the basis of quantum information and underlies some natural processes, but many aspects still need to be explored. Here, the authors, by quantum mechanical computations, show that even a weak spin-orbit coupling near a conical intersection can induce large spin selection, with consequences for spin manipulation in photochemical or electrochemical reactions.
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40
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Bancroft L, Zhang J, Harvey SM, Krzyaniak MD, Zhang P, Schaller RD, Beratan DN, Young RM, Wasielewski MR. Charge Transfer and Spin Dynamics in a Zinc Porphyrin Donor Covalently Linked to One or Two Naphthalenediimide Acceptors. J Phys Chem A 2021; 125:825-834. [PMID: 33449684 DOI: 10.1021/acs.jpca.0c10471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Quantum coherence effects on charge transfer and spin dynamics in a system having two degenerate electron acceptors are studied using a zinc 5,10,15-tri(n-pentyl)-20-phenylporphyrin (ZnP) electron donor covalently linked to either one or two naphthalene-1,8:4,5-bis(dicarboximide) (NDI) electron acceptors using an anthracene (An) spacer, ZnP-An-NDI (1) and ZnP-An-NDI2 (2), respectively. Following photoexcitation of 1 and 2 in toluene at 295 K, femtosecond transient absorption spectroscopy shows that the electron transfer (ET) rate constant for 2 is about three times larger than that of 1, which can be accounted for by the statistical nature of incoherent ET as well as the electron couplings for the charge separation reactions. In contrast, the rate constant for charge recombination (CR) of 1 is about 25% faster than that of 2. Using femtosecond transient infrared spectroscopy and theoretical analysis, we find that the electron on NDI2•- in 2 localizes onto one of the two NDIs prior to CR, thus precluding electronically coherent CR from NDI2•-. Conversely, CR in both 1 and 2 is spin coherent as indicated by the observation of a resonance in the 3*ZnP yield following CR as a function of applied magnetic field, giving spin-spin exchange interaction energies of 2J = 210 and 236 mT, respectively, where the line width of the resonance for 2 is greater than 1. These data show that while CR is a spin-coherent process, incoherent hopping of the electron between the two NDIs in 2, consistent with the lack of delocalization noted above, results in greater spin decoherence in 2 relative to 1.
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Affiliation(s)
- Laura Bancroft
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jinyuan Zhang
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Samantha M Harvey
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Richard D Schaller
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States.,Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Departments of Biochemistry and Physics, Duke University, Durham, North Carolina 27708, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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41
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Ren Y, Hiscock HG, Hore PJ. Angular Precision of Radical Pair Compass Magnetoreceptors. Biophys J 2021; 120:547-555. [PMID: 33421412 PMCID: PMC7896030 DOI: 10.1016/j.bpj.2020.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/17/2020] [Accepted: 12/30/2020] [Indexed: 11/19/2022] Open
Abstract
The light-dependent magnetic compass sense of night-migratory songbirds is thought to rely on magnetically sensitive chemical reactions of radical pairs in cryptochrome proteins located in the birds' eyes. Recently, an information theory approach was developed that provides a strict lower bound on the precision with which a bird could estimate its head direction using only geomagnetic cues and a cryptochrome-based radical pair sensor. By means of this lower bound, we show here how the performance of the compass sense could be optimized by adjusting the orientation of cryptochrome molecules within photoreceptor cells, the distribution of cells around the retina, and the effects of the geomagnetic field on the photochemistry of the radical pair.
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Affiliation(s)
- Yi Ren
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Hamish G Hiscock
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - P J Hore
- Department of Chemistry, University of Oxford, Oxford, United Kingdom.
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42
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Zhai M, Yan X, Liu J, Long Z, Zhao S, Li W, Liu Y, Hai C. Electromagnetic Fields Ameliorate Insulin Resistance and Hepatic Steatosis by Modulating Redox Homeostasis and SREBP-1c Expression in db/db Mice. Diabetes Metab Syndr Obes 2021; 14:1035-1042. [PMID: 33727836 PMCID: PMC7954280 DOI: 10.2147/dmso.s294020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/24/2021] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The prevalence of nonalcoholic fatty liver disease (NAFLD), which has recently become known as metabolic-associated fatty liver disease (MAFLD), has risen. However, pharmacotherapies for this disease have not been approved. Electromagnetic fields (EMFs) have excellent bioeffects on multiple diseases. However, the effects of EMFs on NAFLD are unknown. This study investigated the bioeffects of EMF exposure on insulin resistance, liver redox homeostasis and hepatic steatosis in db/db mice. METHODS Animals were sacrificed after EMF exposure for 8 weeks. The fasting blood glucose and insulin levels in the serum were tested. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated by a formula. The levels of MDA, GSSG and GSH, biomarkers of redox, were assessed. The activities of CAT, SOD and GSH-Px were assessed. The body and liver weights were measured. Hepatic lipid accumulation was observed by Oil Red O staining. Hepatic CAT, GR, GSH-Px, SOD1, SOD2 and SREBP-1 expression was determined by Western blotting. RESULTS EMF exposure ameliorated insulin resistance and oxidative stress in the liver by downregulating the MDA and GSSG levels, increasing the reduced GSH levels, and promoting the GSH-Px levels in db/db mice. In addition, liver weight and triglyceride (TG) levels were reduced by EMF exposure. Simultaneously, EMF exposure improved hepatic steatosis by downregulating the protein expression of SREBP-1c. CONCLUSION The present findings suggest that EMF exposure has positive effects in the treatment of NAFLD.
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Affiliation(s)
- Mingming Zhai
- Department of Biomedical Engineering, Air Force Medical University, Xi’an, People’s Republic of China
| | - Xi Yan
- Department of Dermatology, The Second Affiliated Hospital, Air Force Medical University, Xi’an, People’s Republic of China
| | - Jiangzheng Liu
- Department of Toxicology, Shanxi Provincial Key Lab of Free Radical Biology and Medicine, Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Air Force Medical University, Xi’an, People’s Republic of China
| | - Zi Long
- Department of Toxicology, Shanxi Provincial Key Lab of Free Radical Biology and Medicine, Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Air Force Medical University, Xi’an, People’s Republic of China
| | - Siyan Zhao
- Institute of Nuclear Biological and Chemical Defence, Beijing, People’s Republic of China
| | - Wendan Li
- Institute of Nuclear Biological and Chemical Defence, Beijing, People’s Republic of China
| | - Ying Liu
- Institute of Nuclear Biological and Chemical Defence, Beijing, People’s Republic of China
- Ying Liu Institute of Nuclear Biological and Chemical Defence, No. 1, Yangfang Zhongxin North Street, Beijing, 102205, People’s Republic of China Email
| | - Chunxu Hai
- Department of Toxicology, Shanxi Provincial Key Lab of Free Radical Biology and Medicine, Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Air Force Medical University, Xi’an, People’s Republic of China
- Correspondence: Chunxu Hai Air Force Medical University (AFMU), No. 169 Changle West Road, Xi’an, Shaanxi, 710032, People’s Republic of ChinaTel +86-29-84774879 Email
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43
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Astakhova LA, Rotov AY, Cherbunin RV, Goriachenkov AA, Kavokin KV, Firsov ML, Chernetsov N. Electroretinographic study of the magnetic compass in European robins. Proc Biol Sci 2020; 287:20202507. [PMID: 33290671 DOI: 10.1098/rspb.2020.2507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Migratory birds are known to be sensitive to external magnetic field (MF). Much indirect evidence suggests that the avian magnetic compass is localized in the retina. Previously, we showed that changes in the MF direction could modulate retinal responses in pigeons. In the present study, we performed similar experiments using the traditional model animal to study the magnetic compass, European robins. The photoresponses of isolated retina were recorded using ex vivo electroretinography (ERG). Blue- and red-light stimuli were applied under an MF with the natural intensity and two MF directions, when the angle between the plane of the retina and the field lines was 0° and 90°, respectively. The results were separately analysed for four quadrants of the retina. A comparison of the amplitudes of the a- and b-waves of the ERG responses to blue stimuli under the two MF directions revealed a small but significant difference in a- but not b-waves, and in only one (nasal) quadrant of the retina. The amplitudes of both the a- and b-waves of the ERG responses to red stimuli did not show significant effects of the MF direction. Thus, changes in the external MF modulate the European robin retinal responses to blue flashes, but not to red flashes. This result is in a good agreement with behavioural data showing the successful orientation of birds in an MF under blue, but not under red illumination.
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Affiliation(s)
- Luba A Astakhova
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Alexander Yu Rotov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Roman V Cherbunin
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Arsenii A Goriachenkov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Kirill V Kavokin
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Michael L Firsov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
| | - Nikita Chernetsov
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 44 Toreza Ave., St Petersburg 194223, Russia
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44
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Naaman R, Paltiel Y, Waldeck DH. Chiral Induced Spin Selectivity Gives a New Twist on Spin-Control in Chemistry. Acc Chem Res 2020; 53:2659-2667. [PMID: 33044813 PMCID: PMC7676290 DOI: 10.1021/acs.accounts.0c00485] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The electron's spin, its intrinsic angular momentum, is a quantum property that plays a critical role in determining the electronic structure of molecules. Despite its importance, it is not used often for controlling chemical processes, photochemistry excluded. The reason is that many organic molecules have a total spin zero, namely, all the electrons are paired. Even for molecules with high spin multiplicity, the spin orientation is usually only weakly coupled to the molecular frame of nuclei and hence to the molecular orientation. Therefore, controlling the spin orientation usually does not provide a handle on controlling the geometry of the molecular species during a reaction. About two decades ago, however, a new phenomenon was discovered that relates the electron's spin to the handedness of chiral molecules and is now known as the chiral induced spin selectivity (CISS) effect. It was established that the efficiency of electron transport through chiral molecules depends on the electron spin and that it changes with the enantiomeric form of a molecule and the direction of the electron's linear momentum. This property means that, for chiral molecules, the electron spin is strongly coupled to the molecular frame. Over the past few years, we and others have shown that this feature can be used to provide spin-control over chemical reactions and to perform enantioseparations with magnetic surfaces.In this Account, we describe the CISS effect and demonstrate spin polarization effects on chemical reactions. Explicitly, we describe a number of processes that can be controlled by the electron's spin, among them the interaction of chiral molecules with ferromagnetic surfaces, the multielectron oxidation of water, and enantiospecific electrochemistry. Interestingly, it has been shown that the effect also takes place in inorganic chiral oxides like copper oxide, aluminum oxide, and cobalt oxide. The CISS effect results from the coupling between the electron linear momentum and its spin in a chiral system. Understanding the implications of this interaction promises to reveal a previously unappreciated role for chirality in biology, where chiral molecules are ubiquitous, and opens a new avenue into spin-controlled processes in chemistry.
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Affiliation(s)
- Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot 76100, Israel
| | - Yossi Paltiel
- Applied Physics Department and the Center for Nano-Science and Nano-Technology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - David H. Waldeck
- Chemistry Department, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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45
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Derr JB, Tamayo J, Clark JA, Morales M, Mayther MF, Espinoza EM, Rybicka-Jasińska K, Vullev VI. Multifaceted aspects of charge transfer. Phys Chem Chem Phys 2020; 22:21583-21629. [PMID: 32785306 PMCID: PMC7544685 DOI: 10.1039/d0cp01556c] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Charge transfer and charge transport are by far among the most important processes for sustaining life on Earth and for making our modern ways of living possible. Involving multiple electron-transfer steps, photosynthesis and cellular respiration have been principally responsible for managing the energy flow in the biosphere of our planet since the Great Oxygen Event. It is impossible to imagine living organisms without charge transport mediated by ion channels, or electron and proton transfer mediated by redox enzymes. Concurrently, transfer and transport of electrons and holes drive the functionalities of electronic and photonic devices that are intricate for our lives. While fueling advances in engineering, charge-transfer science has established itself as an important independent field, originating from physical chemistry and chemical physics, focusing on paradigms from biology, and gaining momentum from solar-energy research. Here, we review the fundamental concepts of charge transfer, and outline its core role in a broad range of unrelated fields, such as medicine, environmental science, catalysis, electronics and photonics. The ubiquitous nature of dipoles, for example, sets demands on deepening the understanding of how localized electric fields affect charge transfer. Charge-transfer electrets, thus, prove important for advancing the field and for interfacing fundamental science with engineering. Synergy between the vastly different aspects of charge-transfer science sets the stage for the broad global impacts that the advances in this field have.
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Affiliation(s)
- James B Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
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46
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Hong G, Pachter R, Essen LO, Ritz T. Electron transfer and spin dynamics of the radical-pair in the cryptochrome from Chlamydomonas reinhardtii by computational analysis. J Chem Phys 2020; 152:065101. [PMID: 32061221 DOI: 10.1063/1.5133019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In an effort to elucidate the origin of avian magnetoreception, it was postulated that a radical-pair formed in a cryptochrome upon light activation provided the basis for the mechanism that enables an inclination compass sensitive to the geomagnetic field. Photoreduction in this case involves formation of a flavin adenine dinucleotide (FAD)-tryptophan (TRP) radical-pair, following electron transfer within a conserved TRP triad in the cryptochrome. Recently, an animal-like cryptochrome from Chlamydomonas reinhardtii (CraCRY) was analyzed, demonstrating the role of a fourth aromatic residue, which serves as a terminal electron donor in the photoreduction pathway, resulting in the creation of a more distal radical-pair and exhibiting fast electron transfer. In this work, we investigated the electron transfer in CraCRY with a combination of free energy molecular dynamics (MD) simulations, frozen density functional theory, and QM/MM MD simulations, supporting the suggestion of a proton coupled electron transfer mechanism. Spin dynamics simulations discerned details on the dependence of the singlet yield on the direction of the external magnetic field for the [FAD•- TYRH•+] and [FAD•- TYR•] radical-pairs in CraCRY, in comparison with the previously modeled [FAD•- TRPH•+] radical-pair.
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Affiliation(s)
- Gongyi Hong
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Ruth Pachter
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Lars-Oliver Essen
- Department of Chemistry, Center for Synthetic Microbiology, Philipps University, Marburg 35032, Germany
| | - Thorsten Ritz
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
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47
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Procopio M, Ritz T. The reference-probe model for a robust and optimal radical-pair-based magnetic compass sensor. J Chem Phys 2020; 152:065104. [PMID: 32061231 DOI: 10.1063/1.5128128] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Radical-pair reactions have been suggested to be sensitive to the direction of weak magnetic fields, thereby providing a mechanism for the magnetic compass in animals. Discovering the general principles that make radical pairs particularly sensitive to the direction of weak magnetic fields will be essential for designing bioinspired compass sensors and for advancing our understanding of the spin physics behind directional effects. The reference-probe model is a conceptual model introduced as a guide to identify radical-pair parameters for optimal directional effects. Radical pairs with probe character have been extensively shown to enhance directional sensitivity to weak magnetic fields, but investigations on the role of the reference radical are lacking. Here, we evaluate whether a radical has reference character and then study its relevance for optimal directional effects. We investigate a simple radical-pair model with one axially anisotropic hyperfine interaction using both analytical and numerical calculations. Analytical calculations result in a general expression of the radical-pair reaction yield, which in turn provides useful insights into directional effects. We further investigate the relevance of the reference character to robustness against variations of earth-strength magnetic fields and find that the reference character captures robust features as well. Extending this study to radical pairs with more hyperfine interactions, we discuss the interplay between reference character and optimal and robust directional effects in such more complex radical pairs.
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Affiliation(s)
- Maria Procopio
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Thorsten Ritz
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
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48
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Carter CS, Huang SC, Searby CC, Cassaidy B, Miller MJ, Grzesik WJ, Piorczynski TB, Pak TK, Walsh SA, Acevedo M, Zhang Q, Mapuskar KA, Milne GL, Hinton AO, Guo DF, Weiss R, Bradberry K, Taylor EB, Rauckhorst AJ, Dick DW, Akurathi V, Falls-Hubert KC, Wagner BA, Carter WA, Wang K, Norris AW, Rahmouni K, Buettner GR, Hansen JM, Spitz DR, Abel ED, Sheffield VC. Exposure to Static Magnetic and Electric Fields Treats Type 2 Diabetes. Cell Metab 2020; 32:561-574.e7. [PMID: 33027675 PMCID: PMC7819711 DOI: 10.1016/j.cmet.2020.09.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/29/2020] [Accepted: 09/11/2020] [Indexed: 12/17/2022]
Abstract
Aberrant redox signaling underlies the pathophysiology of many chronic metabolic diseases, including type 2 diabetes (T2D). Methodologies aimed at rebalancing systemic redox homeostasis have had limited success. A noninvasive, sustained approach would enable the long-term control of redox signaling for the treatment of T2D. We report that static magnetic and electric fields (sBE) noninvasively modulate the systemic GSH-to-GSSG redox couple to promote a healthier systemic redox environment that is reducing. Strikingly, when applied to mouse models of T2D, sBE rapidly ameliorates insulin resistance and glucose intolerance in as few as 3 days with no observed adverse effects. Scavenging paramagnetic byproducts of oxygen metabolism with SOD2 in hepatic mitochondria fully abolishes these insulin sensitizing effects, demonstrating that mitochondrial superoxide mediates induction of these therapeutic changes. Our findings introduce a remarkable redox-modulating phenomenon that exploits endogenous electromagneto-receptive mechanisms for the noninvasive treatment of T2D, and potentially other redox-related diseases.
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Affiliation(s)
- Calvin S Carter
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA.
| | - Sunny C Huang
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Charles C Searby
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Benjamin Cassaidy
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Michael J Miller
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Wojciech J Grzesik
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ted B Piorczynski
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, USA
| | - Thomas K Pak
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Susan A Walsh
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Michael Acevedo
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Qihong Zhang
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kranti A Mapuskar
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Ginger L Milne
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Antentor O Hinton
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Deng-Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Robert Weiss
- Department of Internal Medicine, Division of Cardiology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kyle Bradberry
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Eric B Taylor
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Adam J Rauckhorst
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Molecular Physiology and Biophysics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - David W Dick
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Vamsidhar Akurathi
- Department of Radiology, Division of Nuclear Medicine, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kelly C Falls-Hubert
- Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Brett A Wagner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Walter A Carter
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Kai Wang
- College of Public Health, Department of Biostatistics, University of Iowa, Iowa City, IA, USA
| | - Andrew W Norris
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA; Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Garry R Buettner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Jason M Hansen
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, USA
| | - Douglas R Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa Hospitals & Clinics, Iowa City, IA, USA
| | - Val C Sheffield
- Department of Pediatrics and Division of Medical Genetics and Genomics, University of Iowa Hospitals & Clinics, Iowa City, IA, USA.
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49
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Einwich A, Dedek K, Seth PK, Laubinger S, Mouritsen H. A novel isoform of cryptochrome 4 (Cry4b) is expressed in the retina of a night-migratory songbird. Sci Rep 2020; 10:15794. [PMID: 32978454 PMCID: PMC7519125 DOI: 10.1038/s41598-020-72579-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/28/2020] [Indexed: 01/22/2023] Open
Abstract
The primary sensory molecule underlying light-dependent magnetic compass orientation in migratory birds has still not been identified. The cryptochromes are the only known class of vertebrate proteins which could mediate this mechanism in the avian retina. Cryptochrome 4 of the night-migratory songbird the European robin (Erithacus rubecula; erCry4) has several of the properties needed to be the primary magnetoreceptor in the avian eye. Here, we report on the identification of a novel isoform of erCry4, which we named erCry4b. Cry4b includes an additional exon of 29 amino acids compared to the previously described form of Cry4, now called Cry4a. When comparing the retinal circadian mRNA expression pattern of the already known isoform erCry4a and the novel erCry4b isoform, we find that erCry4a is stably expressed throughout day and night, whereas erCry4b shows a diurnal mRNA oscillation. The differential characteristics of the two erCry4 isoforms regarding their 24-h rhythmicity in mRNA expression leads us to suggest that they might have different functions. Based on the 24-h expression pattern, erCry4a remains the more likely cryptochrome to be involved in radical-pair-based magnetoreception, but at the present time, an involvement of erCry4b cannot be excluded.
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Affiliation(s)
- Angelika Einwich
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Pranav Kumar Seth
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Sascha Laubinger
- Institute for Biology and Environmental Sciences, Evolutionäre Genetik der Pflanzen, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.
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50
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Otsuka H, Mitsui H, Miura K, Okano K, Imamoto Y, Okano T. Rapid Oxidation Following Photoreduction in the Avian Cryptochrome4 Photocycle. Biochemistry 2020; 59:3615-3625. [PMID: 32915550 DOI: 10.1021/acs.biochem.0c00495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Avian magnetoreception is assumed to occur in the retina. Although its molecular mechanism is unclear, magnetic field-dependent formation and the stability of radical-containing photointermediate(s) are suggested to play key roles in a hypothesis called the radical pair mechanism. Chicken cryptochrome4 (cCRY4) has been identified as a candidate magnetoreceptive molecule due to its expression in the retina and its ability to form stable flavin neutral radicals (FADH●) upon blue light absorption. Herein, we used millisecond flash photolysis to investigate the cCRY4 photocycle, in both the presence and absence of dithiothreitol (DTT); detecting the anion radical form of FAD (FAD●-) under both conditions. Using spectral data obtained during flash photolysis and UV-visible photospectroscopy, we estimated the absolute absorbance spectra of the photointermediates, thus allowing us to decompose each spectrum into its individual components. Notably, in the absence of DTT, approximately 37% and 63% of FAD●- was oxidized to FADOX and protonated to form FADH●, respectively. Singular value decomposition analysis suggested the presence of two FAD●- molecular species, each of which was destined to be oxidized to FADOX or protonated to FADH●. A tyrosine neutral radical was also detected; however, it likely decayed concomitantly with the oxidation of FAD●-. On the basis of these results, we considered the occurrence of bifurcation prior to FAD●- generation, or during FAD●- oxidization, and discussed the potential role played by the tyrosine radical in the radical pair mechanism.
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Affiliation(s)
- Hiroaki Otsuka
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, Waseda University, TWIns, Wakamatsucho 2-2, Shinjuku-Ku, Tokyo 162-8480, Japan
| | - Hiromasa Mitsui
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, Waseda University, TWIns, Wakamatsucho 2-2, Shinjuku-Ku, Tokyo 162-8480, Japan
| | - Kota Miura
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, Waseda University, TWIns, Wakamatsucho 2-2, Shinjuku-Ku, Tokyo 162-8480, Japan
| | - Keiko Okano
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, Waseda University, TWIns, Wakamatsucho 2-2, Shinjuku-Ku, Tokyo 162-8480, Japan
| | - Yasushi Imamoto
- Department of Biophysics, Division of Biological Sciences, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshiyuki Okano
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, Waseda University, TWIns, Wakamatsucho 2-2, Shinjuku-Ku, Tokyo 162-8480, Japan
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