Unraveling the complexity of anti-doping analysis: reassessing meldonium detection and doping verdicts in a case study.

BACKGROUND: The precision and accuracy of mass spectrometry (MS) made it a fundamental tool in anti-doping analysis. High-resolution (HR) mass spectrometers significantly improved compound identification. This study systematically analyzes data from an athlete (Subject 1) who tested positive for meldonium and compares it with data from a healthy volunteer (Subject 2) to examine the correctness of the doping verdict. CASE PRESENTATION: The documentation related to Subject 1 was thoroughly processed and analyzed. A study involving a volunteer (Subject 2) replicated Subject 1 regimen and urine sample collection for data alignment with anti-doping results, with Subject 2 reporting not using meldonium. The anti-doping agency's analysis of Subject 1 showed the presence of meldonium at a concentration close to the established cut-off level. However, a closer examination revealed that one specific ion, crucial for meldonium identification, was absent from the mass spectra. Analyzing Subject 2 data, using the same methodology, the absence of the specific ion was confirmed, even though the volunteer did not consume meldonium. The European directive and the method that was validated and cited by the anti-doping agency identified meldonium on at least four specific ions, whereas the anti-doping analysis used only three ions. This discrepancy compromises the specificity of meldonium identification. CONCLUSIONS: To enhance the analytical methodology, two strategic interventions are suggested: adjusting the meldonium cut-off value and expanding the analysis to include meldonium metabolites. By addressing these avenues, the precision of meldonium detection and doping verdicts can be improved. In conclusion, this study challenges the anti-doping agency's verdict and prompts a reevaluation of meldonium detection methodologies in anti-doping measures.

Ethanol stress in Oenococcus oeni: transcriptional response and complex physiological mechanisms.

Oenococcus oeni is the dominant species able to cope with a hostile environment of wines, comprising cumulative effects of low pH, high ethanol and SO2 content, nonoptimal growth temperatures and growth inhibitory compounds. Ethanol tolerance is a crucial feature for the activity of O. oeni cells in wine because ethanol acts as a disordering agent of its cell membrane and negatively affects metabolic activity; it damages the membrane integrity, decreases cell viability and, as other stress conditions, delays the start of malolactic fermentation with a consequent alteration of wine quality. The cell wall, cytoplasmic membrane and metabolic pathways are the main sites involved in physiological changes aimed to ensure an adequate adaptive response to ethanol stress and to face the oxidative damage caused by increasing production of reactive oxygen species. Improving our understanding of the cellular impact of ethanol toxicity and how the cell responds to ethanol stress can facilitate the development of strategies to enhance microbial ethanol tolerance; this allows to perform a multidisciplinary endeavour requiring not only an ecological study of the spontaneous process but also the characterization of useful technological and physiological features of the predominant strains in order to select those with the highest potential for industrial applications.

Flow cytometry and capillary electrophoresis analyses in ethanol-stressed Oenococcus oeni strains and changes assessment of membrane fatty acid composition.

AIMS: This study aimed to investigate the dynamics and physiological heterogeneity of Oenococcus oeni under different conditions, cell membrane fluidity and permeability variations, and assessment of changes in cell surface charging rates. METHODS AND RESULTS: Flow cytometry, membrane fatty acid analysis and capillary electrophoresis were performed to study ethanol-induced variations. Different physiological states were assessed, revealing cell subpopulations able to adapt and withstand to environmental stress, in order to recover their functionality. Moreover, total results demonstrated changes in cell surface and membrane fatty acid redistribution with a saturation degree and an unsaturated/saturated fatty acid ratio fairly steady in control and in different ethanol stresses. CONCLUSIONS: This study revealed a great variability among O. oeni strains and the importance to investigate the mechanisms by a multiparametric approach based on the structural and physiological bacterial adjustments in different stresses tolerance. SIGNIFICANCE AND IMPACT OF THE STUDY: Intermediate physiological state assessment in O. oeni with recovery possibility could be an important criterion for potential starter culture application. The flow cytometry application with changes in monitoring membrane fatty acid composition and in surface charging rates allowed the characterization of sorted subpopulations that may contribute to further understanding of diversity and heterogeneity in physiology of bacterial populations.