TY - CONF A1 - Keller, Julia A1 - Koch, Matthias T1 - Interactions of (1,3-dicarbonyl)-mycotoxins and metal ions N2 - Mycotoxins are secondary metabolites of fungi which have diverse detrimental effects on humans, animals and crops. Traceable worldwide in foods and animal feeds, these contaminants cause manifold diseases and extensive economic losses. Therefore, European legislation set maximum levels of distinct mycotoxins to minimize the risks for the buying public. But standardized food analysis techniques fail to detect masked mycotoxins, whose research increasingly moves to the fore in recent years. They are formed from detoxification metabolism of plants as well as from fungi, which conjugate for example with glucosides or dihexosides. All masked mycotoxins have one thing in common: They are not detectable with standard methods, thereby contributing to the overall exposure and pose an additional health risk for the consumer. The dissertation work will focus on the following potential new group of masked toxins. Food safety relevant mycotoxins like zearalenone and ochratoxin A possess one or more 1,3-dicarbonyl moieties. Latter are principally able to form thermodynamically stable chelate complexes with metal cations. First investigations at BAM showed interactions between zearalenone and copper ions and it is conceivable that they possibly build a complex. Our main focus is now to identify, characterize and quantify 1,3-dicarbonyl mycotoxin metal complexes as potential candidates within the group of conjugated mycotoxins. We will simulate processes of biotransformation and identify distinct metabolites by electrochemistry coupled to liquid chromatography/mass spectrometry (EC-HPLC-MS). The obtained knowledge contributes to a better understanding of masked mycotoxins and an improved monitoring of foods and feeds, to ensure food safety. T2 - BAM PhD Retreat CY - Wandlitz, Germany DA - 05.06.2015 KW - Mycotoxins KW - Metal ions PY - 2015 AN - OPUS4-38222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Keller, Julia A1 - Borzekowski, Antje A1 - Haase, H. A1 - Rueß, L. A1 - Menzel, R. A1 - Koch, Matthias T1 - Using the model organism Caenorhabditis elegans for the toxicity testing of citrinin, zearalenone and zearalenone-14-sulfate N2 - To keep up with emerging mycotoxins and their transformation products fast and reliable toxicity tests are needed. Toxicity testing of mycotoxins is carried out usually by performing in vitro assays or is evaluated by using laboratory animals like mice, rats or chicken in in vivo studies. Settled between classical in vitro approaches and in vivo studies with higher animals are tests with the nematode Caenorhabditis elegans. Since Sydney Brenner described 1974 the cultivation and handling of C. elegans, this worm is widely used as model organism in developmental biology and neurology. Due to many benefits like easy and cheap cultivation, a completely sequenced genome and short generation time, it also plays an important role in toxicological research. Finally, the high number of conserved genes between human and C. elegans make the worm an ideal candidate for toxicological investigations. In this study we used C. elegans to assess the toxic effects of the relevant food mycotoxin citrinin (CIT), the mycoestrogen zearalenone (ZEN) and the modified mycotoxin ZEN-14-sulfate (ZEN-14-S) on different lifetable parameters including reproduction, thermal and oxidative stress tolerance and lifespan. All tested mycotoxins significantly decreased the amount of offspring. In case of ZEN and CIT also significant negative effects on stress tolerance and lifespan were observed compared to the control group. Moreover, metabolization of mycotoxins in the worms was investigated by using LC MS/MS. Extraction of the worms treated 5 days with mycotoxin-containing and UVC-killed bacteria showed metabolization of ZEN to α-ZEL and β-ZEL (ZEL = zearalenol, ratio about 3:2). ZEN 14-S was reduced to ZEL 14-S and CIT was metabolized to mono hydroxylated CIT. T2 - 40th Mycotoxin Workshop CY - Munich, Germany DA - 11.06.2018 KW - Mycotoxins KW - Caenorhabditis elegans KW - Toxicity testing PY - 2018 AN - OPUS4-45170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Keller, Julia A1 - Haase, H. A1 - Koch, Matthias T1 - Electrochemistry coupled with mass spectrometry - a versatile tool to investigate metabolic processes of mycotoxins N2 - To understand the metabolic fate of food relevant mycotoxins in vitro systems were mainly used as the method of choice, so far. Yet, in recent years coupling of electrochemistry mass spectrometry (EC-MS) gained increasing importance as promising technique for fast simulation of metabolic processes and was successfully applied in particular for drug metabolism [1]. The aim of our work was to investigate the potential of EC-MS to predict phase I metabolites of priority mycotoxins and to compare the results with in vitro experiments. Hence, the EU-regulated Fusarium mycotoxins zearalenone (ZEN) and patulin as well as dihydroergocristine (DHEC) as model compound of ergot alkaloids were electrochemically oxidized and analyzed by EC MS for the first time. Electrochemical conditions were set-up individually for each of the three mycotoxins. By using a coulometric flow through cell with a diamond working electrode oxidation of the chosen mycotoxins was observed after applying potentials between 1.7 and 2.0 V vs. Pd/H2. The electrochemically generated reaction products were analyzed online by mass-spectrometric detection. All of the three chosen mycotoxins were electrochemically converted to mono- and/or dihydroxylated products confirming the results of ZEN related metabolism studies [2, 3] and in case of DHEC own results from in vitro assays. Due to a lack of metabolism studies concerning the oxidative fate of patulin, interpretation of EC-MS data and performing microsomal studies is of particular relevance. Beside the identified products from electrochemical oxidation of ZEN, patulin and DHEC there is still a number of yet unknown compounds. Additional structural characterization of detected compounds by NMR and X-ray analysis will be facilitated by their large-scale production using preparative EC cells. T2 - Mycotoxin Workshop CY - Berlin, Germany DA - 02.05.2016 KW - Mycotoxins KW - Electrochemistry KW - Biotransformation KW - Mass spectrometry PY - 2016 AN - OPUS4-35981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Keller, Julia A1 - Lörchner, Dominique A1 - Koch, Matthias T1 - Electrochemistry coupled to mass spectrometry (EC/MS) – A valuable tool to simulate metabolic processes of mycotoxins? N2 - Mycotoxins are secondary metabolites produced by fungi contaminating food and feed worldwide. Intake of these foodborne toxins can cause several diseases in humans and animals highlighting the need to understand metabolic pathways of mycotoxins. Methods of choice have been in vitro and in vivo approaches, so far. Beside hundreds of documented mycotoxins numerous new ones need to be elucidated and enhance the demand for fast and reliable methods. Here, we present electrochemistry coupled to mass spectrometry (EC/MS set up Fig. 1) as novel and promising tool in mycotoxin research. Electrochemical oxidation of mycotoxins like zearalenone, citrinin or dihydroergocristine lead to several oxidation products known from phase I biotransformation as well as new interesting reaction products analyzed by EC/MS, LC MS/MS and ESI-HRMS. To ensure a comparative overview results obtained from electrochemical oxidation experiments were compared to Fenton reaction, UV irradiation and microsomal experiments. The presentation will point out the benefits and drawbacks of EC/MS in mycotoxin research on the basis of selected food relevant mycotoxins. T2 - ANAKON CY - Tübingen, Deutschland DA - 03.04.2017 KW - Electrochemistry KW - Mycotoxin KW - Metabolism PY - 2017 AN - OPUS4-39766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -