validation-hyperbaric-pressure-system-with-xenon-anesthesia-for

Validation of Hyperbaric Pressure System with Xenon Anesthesia for <em>Drosophila melanogaster</em>

Under hyperbaric conditions, the elevated concentrations of the ambient gases may elicit a range of behavioral responses in various animals. A substantial ...

University of Buckingham

It has been known for over a century that racemic solutions of hydrogen-bonded compounds are less viscous than their component enantiomers, but this fact has so far remained unexplained. Here we confirm it using enantiomers of lactic acid and compare it to molecular dynamics (MD) simulations of lactic acid viscosity. The effect is absent in classical MD. We suggest that the anomalous viscosity of racemates may be due to a recently discovered magnetic intermolecular force due to spin-dependent charge reorganization.

Anomalous Viscosity of a Racemate: A Simple Experiment Demonstrating Chirally Induced Spin Selectivity.

Visible light triggers free radical production in alive and intact Drosophila 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 s followed by a slower, linear increase for approximately 170 s. 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.

Free radical production induced by visible light in live fruit flies.

It has long been known that phosgene, a war gas and an 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 structure. After exposure to phosgene, every batch of flies consistently displays the Mn (Ⅱ) signal. Regardless of the aftercare provided, these flies inevitably perish, making the signal a diagnostic of phosgene poisoning in flies. The intensity of the signal is dependent on both exposure time and concentration, resembling the kinetics of phosgene poisoning. The signal of Mn (Ⅱ) correlates with the presence of a functional superoxide dismutase Sod2. After exposure, heterozygous Sod2 mutants have a markedly lower intensity of Mn (Ⅱ) in their ESR spectrum. We suggest that phosgene disturbs Mn redox cycling between ESR-silent Mn (Ⅲ) and ESR-active Mn (Ⅱ) that is required for superoxide dismutation. Accordingly, mitochondria of phosgene-treated flies show reduced rates of hydrogen peroxide production, and severely compromised complex I-linked respiration. It is likely that phosgene damages mitochondria through MnSOD and complex I, which contributes to its toxicity. This work uses Drosophila melanogaster for the first time in phosgene research.

Article	Year
Anomalous Viscosity of a Racemate: A Simple Experiment Demonstrating Chirally Induced Spin Selectivity. The journal of physical chemistry letters\| PubMed ID: 35512393	2022
Free radical production induced by visible light in live fruit flies. Journal of photochemistry and photobiology. B, Biology\| PubMed ID: 38703451	2024
A chance insight into phosgene toxicity. Free radical biology & medicine\| PubMed ID: 40550401	2025

Ekin Daplan

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