Evaluation of amino acid profile by targeted metabolomics in the eukaryotic model under exposure of benzo[a]pyrene as the exclusive stressor

Amino acids (AAs) are a class of important metabolites in metabolomics methodology that investigates metab-olite changes in a cell, tissue, or organism for early diagnosis of diseases. Benzo[a]pyrene (BaP) is considered a priority contaminant by different environmental control agencies because it is a proven carcinogenic compound for humans. Therefore, it is important to evaluate the BaP interference in the metabolism of amino acids. In this work, a new amino acid extraction procedure (derivatized with propyl chloroformate/propanol) using func-tionalized magnetic carbon nanotubes was developed and optimized. A hybrid nanotube was used followed by desorption without heating, and excellent extraction of analytes was obtained. After exposure of Saccharomyces cerevisiae, the BaP concentration of 25.0 & mu;mol L-1 caused changes in cell viability, indicating metabolic changes. A fast and efficient GC/MS method using a Phenomenex ZB-AAA column was optimized, enabling the deter-mination of 16 AAs in yeasts exposed or not to BaP. A comparison of AA concentrations obtained in the two experimental groups showed that glycine (Gly), serine (Ser), phenylalanine (Phe), proline (Pro), asparagine (Asn), aspartic acid (Asp), glutamic acid (Glu), tyrosine (Tyr), and leucine (Leu) statistically differentiated, after subsequent application of ANOVA with Bonferroni post-hoc test, with a confidence level of 95%. This amino acid pathway analysis confirmed previous studies that revealed the potential of these AAs as toxicity biomarker candidates.

Automated summary

A new amino acid extraction method using functionalized magnetic carbon nanotubes was developed and optimized, which showed excellent extraction of analytes. Exposure of Saccharomyces cerevisiae to BaP at a concentration of 25.0 μmol L-1 caused changes in cell viability, indicating metabolic alterations. A fast and efficient GC/MS method was optimized to determine 16 amino acids in yeasts exposed or not to BaP. Comparison of amino acid concentrations revealed statistically significant differences in glycine, serine, phenylalanine, proline, asparagine, aspartic acid, glutamic acid, tyrosine, and leucine, suggesting their potential as toxicity biomarker candidates.