Seminários de Espectrometria de Massas

Programação:

– 10h00-10h40 – “Mass spectrometry approaches for studies of selenium food and feed supplementation”
Prof. Joanna Szpunar – Institute of Analytical and Physical Chemistry (IPREM – UMR5254), CNRS, Hélioparc, Pau, France

Abstract: Selenium is an essential trace element that plays a critical role in maintaining the health and well-being of both humans and animals. It is involved in various important physiological processes, including antioxidant defense, immune function, and thyroid hormone metabolism. At the same time, selenium deficiency can lead to significant health issues, making supplementation necessary. As a result, there is a growing demand for selenium-based food and feed supplements. Organic selenium compounds are generally more bioavailable and bioactive compared to inorganic forms. The most widely used organic selenium supplement is selenium-enriched yeast, Saccharomyces cerevisiae, followed by other yeast varieties. Additionally, certain lactic acid bacteria can also convert inorganic selenium into organic forms. At the same time, novel supplements are based on selenium nanoparticles.The toxicological and biological effects of selenium are highly dependent on its specific chemical forms. Inorganic selenium is metabolized by living organisms into a wide array of chemical species, many of which remain unidentified. Selenium can be integrated into low molecular weight compounds (selenometabolites, MW<1 kDa) or into high molecular weight compounds, primarily as selenoproteins containing the rare amino acid selenocysteine. In higher organisms, inorganic selenium is often metabolized into selenosugars, which can decorate proteins via Se-S bonds. The identification and quantification of these individual selenium species is crucial for understanding selenium’s molecular role, its accumulation, and metabolism. Achieving comprehensive coverage of the selenium metabolome is challenging due to the diverse physicochemical properties of selenium-containing molecules. The presentation will highlight recent advances in mass spectrometry-based methods for characterizing selenium species in complex biological matrices [1]. The approaches involve fractionating biological extracts via chromatography, with specific selenium detection using inductively coupled plasma mass spectrometry (ICP MS) and high-resolution Fourier-Transform electrospray mass spectrometry (ESI MSn) to elucidate the structures of detected selenospecies [2,3]. The presentation will discuss several case studies including characterization of selenium metabolomes in probiotic bacteria [4], yeast [1], and supplemented animals [5-6]. 1. K. Bierla, S. Godin, R. Lobinski, J. Szpunar, TrAC Trends in Analytical Chemistry, 2018,104, 87. 2. K. Bierla, G. Chiappetta, J. Vinh, R. Lobinski, J. Szpunar, Frontiers Chem., 2020, 18, 612387. 3. K. Bierla, S.Godin, M. Ladányi, M. Dernovics, J. Szpunar, Metallomics, 2023, 15, mfac097. 4. Z. Hui, K. Bierla, J. Tan, J. Szpunar, D.-J. Chen, R. Lobinski, Metallomics, 2023, 15, 1093. 5. K. Bierla, R.M. Taylor, J. Szpunar, R. Lobinski, R.A. Sunde, Metallomics. 2020, 12, 758-766. 6. K. Bierla, J. Szpunar, R. Lobinski, R.A; Sunde, Metallomics 15, mfad066 and mfad067.

10h50-11h30 – “Speciation analysis in complex systems: the increasing and evolving role of mass spectrometry”
Prof. Ryszard Lobinski – Institute of Analytical and Physical Chemistry (IPREM – UMR5254), CNRS, Hélioparc, Pau, France

Abstract: Metal species refer to the various forms in which metals exist within biological systems, including their oxidation states, coordination environments, and complexes with organic molecules. These species are critical in numerous biochemical processes, such as enzyme catalysis, electron transport, and the regulation of gene expression. Understanding the distribution, function, and dynamics of metal species within cells and tissues is essential for elucidating their roles in health and disease [1]. The advent of -omics technologies, including genomics, proteomics, and metabolomics, has revolutionized the study of biological systems by enabling comprehensive analyses of genes, proteins, and metabolites. When integrated with metal analysis, these approaches facilitate the exploration of metallomics—a field focused on the global analysis of metal species and their interactions within a biological context [2]. Metallomics aims to map the distribution of metals within organisms and understand their biological functions. Advances in high-resolution, high-mass-accuracy (HRAM) mass spectrometry (MS) have transformed speciation analysis. Recent developments in Fourier transform ion cyclotron resonance (FT-ICR) and Orbitrap MS now enable the separate detection of ions differing by a mass of one electron (0.5 mDa) and the measurement of their masses with sub-ppm accuracy. Rather than detecting atoms, it has become possible to target entire molecules based on accurate mass. This shift has moved the challenge from peak capacity in chromatography to peak capacity in a mass spectrum, focusing on molecular signatures such as fine isotopic structure. This lecture discusses the recent advances in speciation analysis, particularly focusing on the analysis of large populations of chemical species in complex systems and their correlation with biological roles. [1] D.M. Templeton, F. Ariese, R. Cornelis, L.G. Danielsson, H. Muntau, H.P. van Leeuwen, R. Lobinski, Pure and Applied Chemistry, 2000, 72,1453-1470. [2] S. Mounicou, J. Szpunar, R. Lobinski, Chemical Society Reviews, 38 (2009) 1119-1138.

Prof. Responsável: Marco Aurélio Zezzi Arruda