Biology subjects

Davy, M.

Publications and source records attributed to Davy, M..

3 recordsLinked to original sources

bioRxiv2025

Capturing in saliva real time emotions induced by a fragrance: an objective emotional assessment based on multiplex molecular biomarker profiles

This study introduces a non-invasive approach to objectively assess fragrance-induced emotions using multiplex salivary biomarker profiling. Traditional methods such as self-reports, physiological monitoring, or neuroimaging are often limited by subjectivity, invasiveness, or poor temporal resolution. Saliva offers a practical alternative, reflecting rapid neuroendocrine changes linked to emotional states. We analyzed four key salivary biomarkers: cortisol (stress, HPA-axis activity), alpha-amylase (sympathetic activation), dehydroepiandrosterone (resilience), and oxytocin (social bonding, emotional regulation) to capture multidimensional emotional responses. Two clinical studies (N=30, N=63) and one consumer study (N=80) exposed healthy volunteers to six fragrances, with saliva collected before, 5 minutes after, and 20 minutes after olfactory stimulation. Subjective ratings of happiness, relaxation, confidence, and dynamism were also obtained via questionnaires. Rigorous analytical validation accounted for reproducibility, circadian variation and sample stability. Biomarker patterns revealed fragrance-specific emotional profiles, with distinct subgroups of participants whose biomarker dynamics correlated with specific emotional states. Increased oxytocin and decreased cortisol consistently aligned with happiness and relaxation, whereas distinct biomarker combinations predicted confidence or dynamism. Classification and regression tree analysis demonstrated high sensitivity for detecting these profiles. Validation in an independent cohort (N=80) using an implicit association test confirmed concordance between molecular profiles and behavioral measures, underscoring the robustness of this method. These findings establish salivary biomarker profiling as a reliable tool for decoding real-time emotional responses. Beyond scientific insights into affective neuroscience, this approach holds translational potential in personalized fragrance design, sensory marketing, and therapeutic applications for stress-related disorders. Expanding the biomarker panel and integrating molecular data with neuroimaging or autonomic measures could further elucidate the interplay between central olfactory processing and peripheral physiology.

neuroscience↗

bioRxiv2025

The role of Akkermansia muciniphila sulfatases in colonic mucinutilisation

Akkermansia muciniphila, an obligate mucin degrader, is a major member of the human colonic microbiota and has been associated positive health outcomes. Mucins are complex glycoproteins that contain heavily sulfated O-glycans and form the protective colonic mucus layer. Bacterial carbohydrate sulfatases are required to metabolise these heavily sulfated mucin glycans and excessive bacterial foraging has been associated with several diseases. Sulfatases have been linked with inflammatory bowel disease, making these microbiota enzymes potential drug targets. A. muciniphila expresses carbohydrate sulfatases that can act on colonic mucins yet their roles in its metabolism remain opaque. Our data reveal that A. muciniphila requires glycopeptides/protein forms of colonic mucin for metabolism and its sulfatases have unique adaptations compared to Bacteroides species. Localisation studies reveal that desulfation of N-acetyl-D-glucosamine, but not D-galactose, is exclusively periplasmic. A cell surface sulfatase has a novel carbohydrate binding module that binds to colonic mucin. This paints a contrasting picture of sulfated mucin metabolism by Akkermansia muciniphila versus Bacteroides species. These data will be important for understanding the contexts for Akkermansia muciniphilas positive health correlations.

biochemistry↗

bioRxiv2025

Isostere 18F-protein post-translational editing enables dynamic tracking of neurodegeneration biomarkers

The neurofilament light chain protein (NfL) is a suggested general marker for neuronal loss. Its release from brain parenchyma into cerebral spinal fluid, and presumed detection in blood has seen it established as a first blood-based marker of disease activity and drug efficacy in multiple sclerosis (MS) and in the presymptomatic diagnosis and assessment of disease course for other neurodegenerative disorders.1 However, the lack of characterisation of its behaviour in circulation, largely due to its antibody-dependent measurement, have hampered the biological interpretation of these measurements, especially after acute injury such as in MS relapse or head trauma.2 Here, we describe a strategy for exploiting positron emission tomography (PET) imaging using isosteric protein mimics following the installation of a fluorine-18 label that is benign enough to provide sensitive, real-time information on the dynamics and trafficking of NfL protein. This circumvents the limits of current methods that integrate 18F into proteins through the bio-conjugation of bulky, unnatural groups, which we show perturb NfLs assembly and functional properties from those in the natural state. We use a visible-light-driven reaction to access radioactive isostere proteins that are unperturbed and so closely resemble their native form. In this way, generation of [18F]fluoroalkyl radicals that can be rapidly reacted at pre-defined sites on proteins creates mimics of proteinogenic side chains bearing near-zero-size labels to probe proteins in functionally true form. These prosthetic-free, protein radiotracers can be generated in excellent radiochemical yield (up to 67%) via a semi-automated protocol in just 15 mins. High associated molar activities (precursor up to 102 GBq mol-1) allowed high sensitivity dynamic observations in blood, brain and cerebrospinal fluid, enabling even the first unambiguous observations of spinal flow kinetics using proteins. These dynamics, including the high rate of spinal flow (on the order of mm per min) and drainage of NfL from CSF into sacral lymph nodes, now provides evidence that the slow fall rate of antibody-detected markers that is observed after acute neural insults is not due to a long half-life, but rather reflects sustained neuronal loss. This discovery will now help to better correlate clinical and radiological features of disease with NfL blood levels. Our methodology now demonstrates the broad potential of a near-zero-size labelling method for the functional study of proteins in whole organisms without interfering with their biological activity and native assembly.

synthetic biology↗