Electron spin resonances of a living system (Drosophila) on normal and carcinogenic diets

We show that the general anesthetics xenon, sulfur hexafluoride, nitrous oxide, and chloroform cause rapid increases of different magnitude and time course in the electron spin content of Drosophila. With the exception of CHCl 3 , these changes are reversible. Anesthetic-resistant mutant strains of Drosophila exhibit a different pattern of spin responses to anesthetic. In two such mutants, the spin response to CHCl 3 is absent. We propose that these spin changes are caused by perturbation of the electronic structure of proteins by general anesthetics. Using density functional theory, we show that general anesthetics perturb and extend the highest occupied molecular orbital of a nine-residue α-helix. The calculated perturbations are qualitatively in accord with the Meyer-Overton relationship and some of its exceptions. We conclude that there may be a connection between spin, electron currents in cells, and the functioning of the nervous system.

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“…This is the case, as shown in ref. 57, and it was replicated with our equipment in Fig. 2, Right, Inset.…”

Section: Resultsmentioning

confidence: 99%

Electron spin changes during general anesthesia in Drosophila

Turin

Skoulakis

Horsfield

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…30 mg, see methods). The central resonance is caused by stable free radicals found in fruit flies, specifically eumelanin, pheomelanin, and sclerotins, henceforth "melanins" 6 ). The bottom trace depicts the same flies following a 10-minute exposure to phosgene diluted in toluene (see methods).…”

Section: Resultsmentioning

confidence: 99%

A chance insight into the mechanism of phosgene toxicity

Daplan,

Turin

2024

Preprint

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It has long been known that phosgene, a deadly war gas and industrial reagent, causes intense oxidative stress, but how it does so remains unclear. Here we report an accidental discovery: electron spin resonance spectroscopy (ESR) of live fruit flies reveals that phosgene exposure results in a distinctive manganese (II) hyperfine spectrum. The Mn(II) signal correlates with mitochondrial SOD2 expression. We suggest that phosgene acylates a highly conserved SOD2 active site tyrosine. This prevents the Mn redox cycling between ESR-silent Mn(III) and ESR-active Mn(II) that is required for superoxide dismutation. We propose that mitochondrial SOD2 inactivation is responsible for phosgene toxicity.

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“…Absorption of X-band microwaves by flies limits the number of flies to about 30. Several studies have been reported on the spin in living systems with ESR (Commoner and Ternberg 1961; Mallard and Kent 1966; Commoner, Townsend, and Pake 1954; Trapp et al 1983).…”

Section: Introductionmentioning

confidence: 99%

Free radical production induced by visible light in live fruit flies

Daplan,

Turin

2024

Preprint

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Visible light triggers free radical production in alive and intactDrosophila melanogaster. We exposed fruit flies to red (613-631 nm), green (515-535 nm), and blue (455-475 nm) light while we monitored changes in unpaired electron content with an electron spin resonance spectrometer (ESR/EPR). The immediate response to light is a rapid increase in spin content lasting approximately 10 seconds followed by a slower, linear increase for approximately 170 seconds. When the light is turned off, the spin population promptly decays with a similar time course, though never fully returning to baseline. The magnitude and time course of the spin production depends on the wavelength of the light. Initially, we surmised that eumelanin might be responsible for the spin change because of its documented ability for visible light absorption and its highly stable free radical content. To explore this, we utilized different fruit fly strains with varying eumelanin content and clarified the relation of melanin types with the spin response. Our findings revealed that flies with darker cuticle have at least three-fold more unpaired electrons than flies with yellow cuticle. However, to our surprise, the increase in unpaired electron population by light was not drastically different amongst the genotypes. This suggests that light-induced free radical production may not exclusively rely on the presence of black melanin, but may instead be dependent on light effects on quinone-based cuticular polymers.

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Electron spin resonances of a living system (Drosophila) on normal and carcinogenic diets

Cited by 7 publications

References 2 publications

Electron spin changes during general anesthesia in Drosophila

Electron spin changes during general anesthesia in Drosophila

A chance insight into the mechanism of phosgene toxicity

Free radical production induced by visible light in live fruit flies

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