TY - JOUR A1 - Borzekowski, Antje A1 - Drewitz, T. A1 - Keller, Julia A1 - Pfeifer, Dietmar A1 - Kunte, Hans-Jörg A1 - Koch, Matthias A1 - Rohn, S. A1 - Maul, R. T1 - Biosynthesis and characterization of zearalenone-14-sulfate, zearalenone-14-glucoside and zearalenone-16-glucoside using common fungal strains N2 - Zearalenone (ZEN) and its phase II sulfate and glucoside metabolites have been detected in food and feed commodities. After consumption, the conjugates can be hydrolyzed by the human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. To include ZEN conjugates in routine analysis, reliable standards are needed, which are currently not available. Thus, the aim of the present study was to develop a facilitated biosynthesis of ZEN-14-sulfate, ZEN-14-glucoside and ZEN-16-glucoside. A metabolite screening was conducted by adding ZEN to liquid fungi cultures of known ZEN conjugating Aspergillus and Rhizopus strains. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. In addition, a consecutive biosynthesis was developed by using Fusarium graminearum for ZEN biosynthesis with subsequent conjugation of the toxin by utilizing Aspergillus and Rhizopus species. ZEN-14-sulfate (yield: 49%) is exclusively formed by Aspergillus oryzae. ZEN-14-glucoside (yield: 67%) and ZEN-16-glucoside (yield: 39%) are formed by Rhizopus oryzae and Rhizopus oligosporus, respectively. Purities of ≥73% ZEN-14-sulfate, ≥82% ZEN-14-glucoside and ≥50% ZEN-16-glucoside were obtained by 1H-NMR. In total, under optimized cultivation conditions, fungi can be easily utilized for a targeted and regioselective synthesis of ZEN conjugates. KW - Mycotoxin KW - Zearalenone KW - Conjugate KW - Biosynthesis KW - Fusarium KW - Aspergillus KW - Rhizopus PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444246 DO - https://doi.org/10.3390/toxins10030104 SN - 2072-6651 VL - 10 IS - 3 SP - Article 104, 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-44424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schloß, Svenja A1 - Koch, Matthias A1 - Rohn, S. A1 - Maul, R. T1 - Development of a SIDA-LC-MS/MS method for the determination of phomopsin A in legumes N2 - A novel method for the determination of phomopsin A (1) in lupin flour, pea flour, and bean flour as well as whole lupin plants was established based on stable isotope dilution assay (SIDA) LC-MS/MS using 15N6-1 as an isotopically labeled internal standard. Artificially infected samples were used to develop an optimized extraction procedure and sample pretreatment. The limits of detection were 0.5–1 µg/kg for all matrices. The limits of quantitation were 2–4 µg/kg. The method was used to analyze flour samples generated from selected legume seeds and lupin plant samples that had been inoculated with Diaporthe toxica and two further fungal strains. Finally, growing lupin plants infected with D. toxica were investigated to simulate a naturally in-field mycotoxicosis. Toxin levels of up to 10.1 µg/kg of 1 were found in the pods and 7.2 µg/kg in the stems and leaves. KW - Diaporthe toxica KW - Stable isotope dilution assay KW - Isotopic labeled internal standard KW - Legume contamination PY - 2015 DO - https://doi.org/10.1021/acs.jafc.5b04792 SN - 0021-8561 SN - 1520-5118 VL - 63 IS - 48 SP - 10543 EP - 10549 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-35071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schloß, S. A1 - Hackl, T. A1 - Herz, C. A1 - Lamy, E. A1 - Koch, Matthias A1 - Rohn, S. A1 - Maul, R. T1 - Detection of a Toxic Methylated Derivative of Phomopsin A Produced by the Legume-Infesting Fungus Dioporthe toxica N2 - Phomopsin A (PHO-A), produced by the fungus Diaporthe toxica, is a mycotoxin known to be responsible for fatal liver disease of lupin-fed sheep. The füll spectrum of the toxic secondary metabolites produced by D. toxica is still unknown. PHO-A and the naturally occurring derivatives B—E have been subject to several studies to reveal their structures as well as chemical and toxicological properties. In this work, a methylated derivative of PHO-Aisolated firom lupin seeds inoculated %vith D. toxica is described. It was characterized by high-resolution mass and NMR data and shown to be the N-methylated derivative of PHO-A 1 is cytotoxic againstHepG2 cells. KW - Mycotoxins KW - Identification KW - Food PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411167 DO - https://doi.org/10.1021/acs.jnatprod.6b00662 VL - 80 IS - 6 SP - 1930 EP - 1934 PB - ACS Publications AN - OPUS4-41116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maul, R. T1 - Phomopsins in legumes - a multidimensional approach N2 - Fungal secondary metabolites such as phomopsin A (PHO-A) produced by the fungus Diaporthe toxica are referred to as “emerging” mycotoxins. Recently, we developed a biosynthetic approach to gain access to 15N-isotopically labelled PHO-A as internal standard (IS) for PHO-A matrix independent quantification of PHO-A in various commodities. Aim of the present work was to elucidate the applicability of the new IS for accurate quantification and to investigate the phomopsin formation on various legume seeds as well as plant material. In summary, the applicability of the SIDA-HPLC-MS/MS method could be proven and the potential of D. toxica to produce high amounts of phomopsins under unfavorable conditions on lupins and other legume seeds could be shown. Moreover, a novel toxic methylated PHO-A derivative was unveiled in natural samples infested with D. toxica. T2 - 38. Mycotoxin-Workshop CY - Berlin, Germany DA - 02.05.2016 KW - Phomopsin-Derivate KW - Leguminosen KW - Stabilisotopenverdünnungsanalyse KW - HPLC-MS/MS KW - HRMS-Identifizierung KW - Toxizität PY - 2016 AN - OPUS4-37056 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -