Publications by authors named "Luca Turin"

The question of what generates conscious experience has mesmerized thinkers since the dawn of humanity, yet its origins remain a mystery. The topic of consciousness has gained traction in recent years, thanks to the development of large language models that now arguably pass the Turing test, an operational test for intelligence. However, intelligence and consciousness are not related in obvious ways, as anyone who suffers from a bad toothache can attest-pain generates intense feelings and absorbs all our conscious awareness, yet nothing particularly intelligent is going on.

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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.

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The oxygen reduction reaction (ORR) is of high importance, among others, because of its role in cellular respiration and in the operation of fuel cells. Recently, a possible relation between respiration and general anesthesia has been found. This work aims to explore whether anesthesia related gases affect the ORR.

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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.

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Although the involvement of pathological tau in neurodegenerative dementias is indisputable, its physiological roles have remained elusive in part because its abrogation has been reported without overt phenotypes in mice and This was addressed using the recently described and Mi{MIC} mutants and focused on molecular and behavioral analyses. Initially, we show that tau (dTau) loss precipitates dynamic cytoskeletal changes in the adult CNS and translation upregulation. Significantly, we demonstrate for the first time distinct roles for dTau in adult mushroom body (MB)-dependent neuroplasticity as its downregulation within α'β'neurons impairs habituation.

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Changes in electron spin content can be detected by X-band continuous-wave electron spin resonance (ESR, EPR) in Drosophila fruit flies without requiring the use of spin traps. The spin changes are related to cellular respiration and behave differently in anesthesia-resistant fly strains. We describe the method used in these measurements and its possible applications to the problem of the mechanism of general anesthesia.

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A remarkable feature of olfaction, and perhaps the hardest one to explain by shape-based molecular recognition, is the ability to detect the presence of functional groups in odorants, irrespective of molecular context. We previously showed that trained to avoid deuterated odorants could respond to a molecule bearing a nitrile group, which shares the vibrational stretch frequency with the CD bond. Here, we reproduce and extend this finding by showing analogous olfactory responses of to the chemically vastly different functional groups, thiols and boranes, that nevertheless possess a common vibration at 2600 cm.

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Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues.

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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 CHCl3, these changes are reversible. Anesthetic-resistant mutant strains of Drosophila exhibit a different pattern of spin responses to anesthetic.

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Whether olfaction recognizes odorants by their shape, their molecular vibrations, or both remains an open and controversial question. A convenient way to address it is to test for odor character differences between deuterated and undeuterated odorant isotopomers, since these have identical ground-state conformations but different vibrational modes. In a previous paper (Franco et al.

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A common explanation of molecular recognition by the olfactory system posits that receptors recognize the structure or shape of the odorant molecule. We performed a rigorous test of shape recognition by replacing hydrogen with deuterium in odorants and asking whether Drosophila melanogaster can distinguish these identically shaped isotopes. We report that flies not only differentiate between isotopic odorants, but can be conditioned to selectively avoid the common or the deuterated isotope.

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