Time-resolved and modulation methods in the study of the effects of magnetic fields on the yields of free-radical reactions

Batchelor, S. N.; Kay, Christopher W. M.; McLauchlan, K.A.; Shkrob, Ilya A.

doi:10.1021/j100152a032

Cited by 77 publications

(61 citation statements)

References 11 publications

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“…Lifetimes of >100 ns are common in many radical pairs and eVects of 100 T Welds have been demonstrated in radical pairs with such lifetimes (Batchelor et al 1993;Brocklehurst and McLauchlan 1996;Galland and Pazur 2005). The lifetime of FADH• Trp• radical pairs in Escherichia coli CPD photolyase is exceptionally long, on the order of 10 s (Weber 2005; see also Cintolesi et al 2003 and references therein).…”

Section: Radical-pair Mechanismmentioning

confidence: 99%

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Ahmad

Galland

Ritz

et al. 2006

Planta

177

192

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Cryptochromes are blue-light absorbing photoreceptors found in many organisms where they have been involved in numerous growth, developmental, and circadian responses. In Arabidopsis thaliana, two cryptochromes, CRY1 and CRY2, mediate several blue-light-dependent responses including hypocotyl growth inhibition. Our study shows that an increase in the intensity of the ambient magnetic field from 33-44 to 500 muT enhanced growth inhibition in A. thaliana under blue light, when cryptochromes are the mediating photoreceptor, but not under red light when the mediating receptors are phytochromes, or in total darkness. Hypocotyl growth of Arabidopsis mutants lacking cryptochromes was unaffected by the increase in magnetic intensity. Additional cryptochrome-dependent responses, such as blue-light-dependent anthocyanin accumulation and blue-light-dependent degradation of CRY2 protein, were also enhanced at the higher magnetic intensity. These findings show that higher plants are sensitive to the magnetic field in responses that are linked to cryptochrome-dependent signaling pathways. Because cryptochromes form radical pairs after photoexcitation, our results can best be explained by the radical-pair model. Recent evidence indicates that the magnetic compass of birds involves a radical pair mechanism, and cryptochrome is a likely candidate for the avian magnetoreception molecule. Our findings thus suggest intriguing parallels in magnetoreception of animals and plants that appear to be based on common physical properties of photoexcited cryptochromes.

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Section: Radical-pair Mechanismmentioning

confidence: 99%

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Ahmad

Galland

Ritz

et al. 2006

Planta

177

192

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“…In order to recombine the two unpaired electrons must have antiparallel spins [Brocklehurst and McLauchlan, 1996]. It has been shown that the application of a magnetic field can affect the proportion of radical pairs in the parallel to antiparallel state thus influencing the ability for them to recombine [Monchick and Adrian, 1978;Batchelor et al, 1993;Henbest et al, 2006;Solov'yov et al, 2007].…”

Section: Introductionmentioning

confidence: 99%

Effect of 100 mT homogeneous static magnetic field on [Ca²⁺]_c response to ATP in HL‐60 cells following GSH depletion

Belton

Prato

Rozanski

et al. 2009

Bioelectromagnetics

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Calcium is an important molecule in a number of biological systems. Often these systems are signal transduction cascades involving molecules such as ATP. ATP activates second messengers which can interact with ion channels on the endoplasmic/sarcoplasmic reticulum resulting in the emptying of the intracellular calcium stores and an increase in cytosolic free calcium concentration ([Ca2+]c). Changes in [Ca2+]c can be influenced by external factors such as a static magnetic field (SMF). One hypothesis suggests that a SMF affects the cells through the radical pair mechanism. By reducing the number of antioxidant molecules like glutathione (GSH), the proportion of free radicals in the cells is increased and may lead to a greater probability of a biological response to a SMF. The purpose of this study was to determine if the [Ca2+]c response to ATP was affected by depletion of GSH by diethylmaleate (DEM) and the absence or presence of a 100 mT homogeneous SMF. Undifferentiated HL-60 cells were loaded with fura-2 AM. [Ca2+]c was measured in real time using a ratiometric fluorescence spectroscopy system. Various (DEM) ranging from 1 to 15 mM were added to deplete GSH. Cells were either exposed to sham or magnetic field (100 mT) for 13 min (780 s) and challenged with 1 microM ATP. The data show that [Ca2+]c was elevated following treatment with DEM with greater [Ca2+]c at higher [DEM]. The [Ca2+]c response to ATP was decreased as the DEM concentration increased. However, there was no effect of a 100 mT SMF on the average [Ca2+]c peak following ATP activation or the full width at half maximum (FWHM) of the [Ca2+]c response and recovery after ATP activation.

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“…Up to now, many spectrophotometric experiments demonstrated a significant variation in the yield of reaction products under weak static and time-varying magnetic field, using for example the exciplex [9,10]. Nevertheless, in RPM, the radicals involved in the pair are intrinsically paramagnetic and are an expected target for EPR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Improvements in technical assessment and protocol for EPR evaluation of magnetic fields effects on a radical pair reaction

Gualtieri

Colacicchi

Carnicelli

et al. 2005

Biophysical Chemistry

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Time-resolved and modulation methods in the study of the effects of magnetic fields on the yields of free-radical reactions

Cited by 77 publications

References 11 publications

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Effect of 100 mT homogeneous static magnetic field on [Ca²⁺]_c response to ATP in HL‐60 cells following GSH depletion

Improvements in technical assessment and protocol for EPR evaluation of magnetic fields effects on a radical pair reaction

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Time-resolved and modulation methods in the study of the effects of magnetic fields on the yields of free-radical reactions

Cited by 77 publications

References 11 publications

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Magnetic intensity affects cryptochrome-dependent responses in Arabidopsis thaliana

Effect of 100 mT homogeneous static magnetic field on [Ca2+]c response to ATP in HL‐60 cells following GSH depletion

Improvements in technical assessment and protocol for EPR evaluation of magnetic fields effects on a radical pair reaction

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Effect of 100 mT homogeneous static magnetic field on [Ca²⁺]_c response to ATP in HL‐60 cells following GSH depletion