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Uzhytchak M, Smolková B, Frtús A, Stupakov A, Lunova M, Scollo F, Hof M, Jurkiewicz P, Sullivan GJ, Dejneka A, Lunov O. Sensitivity of endogenous autofluorescence in HeLa cells to the application of external magnetic fields. Sci Rep 2023; 13:10818. [PMID: 37402779 DOI: 10.1038/s41598-023-38015-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/30/2023] [Indexed: 07/06/2023] Open
Abstract
Dramatically increased levels of electromagnetic radiation in the environment have raised concerns over the potential health hazards of electromagnetic fields. Various biological effects of magnetic fields have been proposed. Despite decades of intensive research, the molecular mechanisms procuring cellular responses remain largely unknown. The current literature is conflicting with regards to evidence that magnetic fields affect functionality directly at the cellular level. Therefore, a search for potential direct cellular effects of magnetic fields represents a cornerstone that may propose an explanation for potential health hazards associated with magnetic fields. It has been proposed that autofluorescence of HeLa cells is magnetic field sensitive, relying on single-cell imaging kinetic measurements. Here, we investigate the magnetic field sensitivity of an endogenous autofluorescence in HeLa cells. Under the experimental conditions used, magnetic field sensitivity of an endogenous autofluorescence was not observed in HeLa cells. We present a number of arguments indicating why this is the case in the analysis of magnetic field effects based on the imaging of cellular autofluorescence decay. Our work indicates that new methods are required to elucidate the effects of magnetic fields at the cellular level.
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Affiliation(s)
- Mariia Uzhytchak
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
| | - Barbora Smolková
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
| | - Adam Frtús
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
| | - Alexandr Stupakov
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
| | - Mariia Lunova
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
- Institute for Clinical and Experimental Medicine (IKEM), Prague, 14021, Czech Republic
| | - Federica Scollo
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, 18223, Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, 18223, Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, 18223, Czech Republic
| | - Gareth John Sullivan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Department of Pediatric Research, Oslo University Hospital, Oslo, Norway
- Department of Immunology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Alexandr Dejneka
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic
| | - Oleg Lunov
- Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18221, Czech Republic.
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Oka Y, Miura T, Ikoma T. Photogenerated Radical Pair between Flavin and a Tryptophan-Containing Transmembrane-Type Peptide in a Large Unilamellar Vesicle. J Phys Chem B 2021; 125:4057-4066. [PMID: 33858138 DOI: 10.1021/acs.jpcb.1c01231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron-transfer (ET) reactions in biological systems, such as those with magnetic sensors based on flavoproteins and electron transport at biomembrane interfaces, are interesting and important issues that require understanding. As a model system of flavoproteins in biomimetic environments, we report the dynamics of the radical pair generated by photoinduced ET between riboflavin tetrabutylate (RFTB) and tryptophan (Trp) residues in a transmembrane-type polypeptide, both of which are distributed in a large unilamellar vesicle of 1,2-dimyristoyl-sn-glycero-3-phosphocholine. The Trp residues locate near the hydrophilic membrane interface, as confirmed by a dual-fluorescence quenching assay. The fluorescence and transient absorption upon photoexcitation of RFTB indicate that ET from both the singlet and triplet excited states occurs at the hydrophilic interface, whereas the RFTB in the hydrophobic region does not contribute to ET. The ET efficiency and the magnetic field effect (MFE) on the RFTB anion increase significantly above the gel-to-liquid crystal phase transition temperature due to a decrease in microviscosity. The MFE analysis indicates that the radical pair generated from the triplet ET channel exhibits a long lifetime as those in micellar systems due to the strong cage effect of the vesicle.
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Affiliation(s)
- Yoshimi Oka
- Frontier Research Core for Life Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Tomoaki Miura
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Tadaaki Ikoma
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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Yoshimura N, Kobayashi A, Yoshida M, Kato M. Enhancement of Photocatalytic Activity for Hydrogen Production by Surface Modification of Pt‐TiO
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Nanoparticles with a Double Layer of Photosensitizers. Chemistry 2020; 26:16939-16946. [PMID: 33067824 DOI: 10.1002/chem.202003990] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Nobutaka Yoshimura
- Department of Chemistry Faculty of Science Hokkaido University North-10 West-8 Kita-ku Sapporo 0600810 Japan
| | - Atsushi Kobayashi
- Department of Chemistry Faculty of Science Hokkaido University North-10 West-8 Kita-ku Sapporo 0600810 Japan
| | - Masaki Yoshida
- Department of Chemistry Faculty of Science Hokkaido University North-10 West-8 Kita-ku Sapporo 0600810 Japan
| | - Masako Kato
- Department of Chemistry Faculty of Science Hokkaido University North-10 West-8 Kita-ku Sapporo 0600810 Japan
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Sebata S, Takizawa SY, Ikuta N, Murata S. Photofunctions of iridium(iii) complexes in vesicles: long-lived excited states and visible-light sensitization for hydrogen evolution in aqueous solution. Dalton Trans 2019; 48:14914-14925. [DOI: 10.1039/c9dt03144h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Utilization of DPPC vesicles allows water-insoluble photoactive Ir(iii) complexes to be dispersed in bulk aqueous solution.
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Affiliation(s)
- Shinogu Sebata
- Department of Basic Science
- Graduate School of Arts and Sciences
- The University of Tokyo
- Tokyo 153-8902
- Japan
| | - Shin-ya Takizawa
- Department of Basic Science
- Graduate School of Arts and Sciences
- The University of Tokyo
- Tokyo 153-8902
- Japan
| | - Naoya Ikuta
- Department of Basic Science
- Graduate School of Arts and Sciences
- The University of Tokyo
- Tokyo 153-8902
- Japan
| | - Shigeru Murata
- Department of Basic Science
- Graduate School of Arts and Sciences
- The University of Tokyo
- Tokyo 153-8902
- Japan
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