Combination of Isotope Labeling and Molecular Networking of Tandem Mass Spectrometry Data To Reveal 69 Unknown Metabolites Produced by <i>Penicillium nordicum</i>

Published on 2019-09-11T18:40:06Z (GMT) by
The secondary metabolome of <i>Penicillium nordicum</i> is poorly documented despite its frequent detection on contaminated food and its capacity to produce toxic metabolites such as ochratoxin A. To characterize metabolites produced by this fungi, we combined a full stable isotopes labeling with the dereplication of tandem mass spectrometry (MS/MS) data by molecular networking. First, the untargeted metabolomic analysis by high-resolution mass spectrometry of a double stable isotope labeling of <i>P. nordicum</i> enabled the specific detection of its metabolites and the unambiguous determination of their elemental composition. Analyses showed that infection of substrate by <i>P. nordicum</i> lead to the production of at least 92 metabolites and that 69 of them were completely unknown. Then, curated molecular networks of MS/MS data were generated with GNPS and MetGem, specifically on the features of interest, which allowed highlighting 13 fungisporin-related metabolites that had not previously been identified in this fungus and 8 that had never been observed in any fungus. The structures of the unknown compounds, namely, a native fungisporin and seven linear peptides, were characterized by tandem mass spectrometry experiments. The analysis of <i>P. nordicum</i> growing on its natural substrates, i.e. pork ham, turkey ham, and cheese, demonstrated that 10 of the known fungisporin-related metabolites and three of the new metabolites were also synthesized. Thus, the curation of data for molecular networking using a specific detection of metabolites of interest with stable isotopes labeling allowed the discovery of new metabolites produced by the food contaminant <i>P. nordicum</i>.

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Hautbergue, Thaïs; Jamin, Emilien L.; Costantino, Robin; Tadrist, Souria; Meneghetti, Lauriane; Tabet, Jean-Claude; et al. (2019): Combination of Isotope Labeling and Molecular Networking

of Tandem Mass Spectrometry Data To Reveal 69 Unknown Metabolites

Produced by Penicillium nordicum. ACS Publications. Collection.