title: Top-down Metabolomic Approaches for Nitrogen-Containing Metabolites.
abstract: Streamlining the processes that reveal heteroatom-containing metabolites and their biosynthetic genes is essential in integrated metabolomics studies. These metabolites are especially targeted for their potential pharmaceutical activities. By using a Fourier-transform ion cyclotron resonance-mass spectrometry (FTICR-MS) instrument, we provide top-down targeted metabolomic analyses using ultrahigh-resolution liquid chromatography-mass spectrometry (LC-MS), high-resolution matrix-assisted laser desorption/ionization (MALDI), and high-resolution imaging mass spectrometry (IMS) with15N labeling of nitrogen-containing metabolites. In this study, we efficiently extract known and unknown chemicals and spatial information from the medicinal plant Catharanthus roseus, which sources several cancer drugs. The ultrahigh-resolution LC-MS analysis showed that the molecular formula of 65 N-metabolites were identified using the petals, peduncles, leaves, petioles, stems, and roots of the non- and15N-labeled Catharanthus plants. The high resolution MALDI analysis showed the molecular formula of 64 N-metabolites using the petals, leaves, and stems of the non- and15N-labeled Catharanthus. The chemical assignments using molecular formulas stored in databases identified known and unknown metabolites. The comparative analyses using the assigned metabolites revealed that most of the organ-specific ions are derived from unknown N-metabolites. The high-resolution IMS analysis characterized the spatial accumulation patterns of 32 N-metabolites using the buds, leaves, stems, and roots in Catharanthus. The comparative analysis using the non- and15N-labeled IMS data showed the same spatial accumulation patterns of a non- and15N-labeled metabolite in the organs, showing that top-down analysis can be performed even in IMS analysis.
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
authors.forename: Ryo
authors.identifier: 0000-0002-8674-0928
authors.initials: R
authors.lastname: Nakabayashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
authors.forename: Kiminori
authors.initials: K
authors.lastname: Toyooka
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.|Graduate School of Pharmaceutical Sciences, Chiba University , 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000378:metabolism; D030008:Catharanthus / Q000737:chemistry / Q000378:metabolism; D007553:Isotope Labeling; D055442:Metabolome; D055432:Metabolomics; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D018547:Plant Stems / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared; D053719:Tandem Mass Spectrometry
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D009584:Nitrogen