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Soukup ST, Kohn BN, Pfeiffer E, Geisen R, Metzler M, Bunzel M, Kulling SE. Sulfoglucosides as Novel Modified Forms of the Mycotoxins Alternariol and Alternariol Monomethyl Ether. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:8892-8901. [PMID: 27776211 DOI: 10.1021/acs.jafc.6b03120] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The mycotoxins alternariol and alternariol-9-O-methyl ether have recently been reported to be extensively conjugated with glucose and malonyl glucose in tobacco suspension cells. However, only trace amounts of glucosylated conjugates were detected in tomatoes inoculated with Alternaria alternata in the present study. Instead, mostly sulfate conjugates were observed. In studies using cultures of A. alternata and incubations of alternariol and alternariol-9-O-methyl ether with tomato tissue in the absence of the fungus, it was clarified that sulfate conjugates were produced by the fungus, whereas tomato tissues converted alternariol and alternariol-9-O-methyl ether to glucosylated metabolites. Alternariol-3-sulfate, alternariol-9-sulfate, and alternariol-9-O-methyl ether-3-sulfate were unambiguously identified as fungal metabolites using MS and 1H and 13C NMR spectroscopy. When these sulfate conjugates were incubated with tobacco suspension cells or ex planta tomato tissues, three sulfoglucosides of alternariol and one sulfoglucoside of alternariol-9-O-methyl ether were formed. Using NMR spectroscopy, the chemical structures of alternariol-3-sulfate-9-glucoside, alternariol-9-sulfate-3-glucoside, and alternariol-9-O-methyl ether-3-sulfate-7-glucoside were established. These conjugates were also detected in the A. alternata-inoculated tomato. This is the first report on a mixed sulfate/glucoside diconjugate of a mycotoxin. Diconjugates of this novel type may be formed by all mycotoxins and their phase I metabolites with two or more hydroxyl groups and should be taken into account in the future analysis of modified mycotoxins.
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Affiliation(s)
- Sebastian T Soukup
- Department of Safety and Quality of Fruits and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food , Haid-und-Neu-Straße 9, 76131 Karlsruhe, Germany
| | - Beate N Kohn
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT) , Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Erika Pfeiffer
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT) , Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Rolf Geisen
- Department of Safety and Quality of Fruits and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food , Haid-und-Neu-Straße 9, 76131 Karlsruhe, Germany
| | - Manfred Metzler
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT) , Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Mirko Bunzel
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT) , Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Sabine E Kulling
- Department of Safety and Quality of Fruits and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food , Haid-und-Neu-Straße 9, 76131 Karlsruhe, Germany
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Zwickel T, Kahl SM, Klaffke H, Rychlik M, Müller MEH. Spotlight on the Underdogs-An Analysis of Underrepresented Alternaria Mycotoxins Formed Depending on Varying Substrate, Time and Temperature Conditions. Toxins (Basel) 2016; 8:toxins8110344. [PMID: 27869760 PMCID: PMC5127140 DOI: 10.3390/toxins8110344] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 11/11/2016] [Accepted: 11/13/2016] [Indexed: 01/11/2023] Open
Abstract
Alternaria (A.) is a genus of widespread fungi capable of producing numerous, possibly health-endangering Alternaria toxins (ATs), which are usually not the focus of attention. The formation of ATs depends on the species and complex interactions of various environmental factors and is not fully understood. In this study the influence of temperature (7 °C, 25 °C), substrate (rice, wheat kernels) and incubation time (4, 7, and 14 days) on the production of thirteen ATs and three sulfoconjugated ATs by three different Alternaria isolates from the species groups A. tenuissima and A. infectoria was determined. High-performance liquid chromatography coupled with tandem mass spectrometry was used for quantification. Under nearly all conditions, tenuazonic acid was the most extensively produced toxin. At 25 °C and with increasing incubation time all toxins were formed in high amounts by the two A. tenuissima strains on both substrates with comparable mycotoxin profiles. However, for some of the toxins, stagnation or a decrease in production was observed from day 7 to 14. As opposed to the A. tenuissima strains, the A. infectoria strain only produced low amounts of ATs, but high concentrations of stemphyltoxin III. The results provide an essential insight into the quantitative in vitro AT formation under different environmental conditions, potentially transferable to different field and storage conditions.
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Affiliation(s)
- Theresa Zwickel
- Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str 8-10, Berlin 10589, Germany.
- Technische Universität München, Chair of Analytical Food Chemistry, Alte Akademie 10, Freising 85354, Germany.
| | - Sandra M Kahl
- Leibniz-Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, Eberswalder Str. 84, Müncheberg 15374, Germany.
- University of Potsdam, Maulbeerallee 1, Potsdam 14469, Germany.
| | - Horst Klaffke
- Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str 8-10, Berlin 10589, Germany.
| | - Michael Rychlik
- Technische Universität München, Chair of Analytical Food Chemistry, Alte Akademie 10, Freising 85354, Germany.
| | - Marina E H Müller
- Leibniz-Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Biogeochemistry, Eberswalder Str. 84, Müncheberg 15374, Germany.
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Risk evaluation of the Alternaria mycotoxin tenuazonic acid in foods for adults and infants and subsequent risk management. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.03.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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De Bruyne L, Van Poucke C, Di Mavungu DJ, Zainudin NAIM, Vanhaecke L, De Vleesschauwer D, Turgeon BG, De Saeger S, Höfte M. Comparative chemical screening and genetic analysis reveal tentoxin as a new virulence factor in Cochliobolus miyabeanus, the causal agent of brown spot disease on rice. MOLECULAR PLANT PATHOLOGY 2016; 17:805-17. [PMID: 26456797 PMCID: PMC6638388 DOI: 10.1111/mpp.12329] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Brown spot disease, caused by Cochliobolus miyabeanus, is currently considered to be one of the most important yield reducers of rice (Oryza sativa L.). Despite its agricultural importance, little is known about the virulence mechanisms deployed by the fungus. Therefore, we set out to identify novel virulence factors with a role in disease development. This article reports, for the first time, the production of tentoxin by C. miyabeanus as a virulence factor during brown spot disease and the identification of the non-ribosomal protein synthetase (NRPS) CmNps3, responsible for tentoxin biosynthesis. We compared the chemical compounds produced by C. miyabeanus strains differing in virulence ability using ultra-high-performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry (HRMS). The production of tentoxin by a highly virulent strain was revealed by principal component analysis of the detected ions and confirmed by UHPLC coupled to tandem-quadrupole mass spectrometry (MS/MS). The corresponding NRPS was identified by in silico genome analysis and confirmed by gene deletion. Infection tests with wild-type and Cmnps3 mutants showed that tentoxin acts as a virulence factor and is correlated with chlorosis development during the second phase of infection. Although rice has previously been classified as a tentoxin-insensitive plant species, our data demonstrate that tentoxin production by C. miyabeanus affects symptom development.
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Affiliation(s)
- Lieselotte De Bruyne
- Department of Crop Protection, Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, BE-9000, Ghent, Belgium
| | - Christof Van Poucke
- Department of Bio-analysis, Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, BE-9000, Ghent, Belgium
| | - Diana Jose Di Mavungu
- Department of Bio-analysis, Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, BE-9000, Ghent, Belgium
| | - Nur Ain Izzati Mohd Zainudin
- Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, 14850, Ithaca, NY, USA
- Department of Biology, Faculty of Science, University Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Lynn Vanhaecke
- Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Faculty of Veterinary Medicine, Ghent University, BE-9000, Ghent, Belgium
| | - David De Vleesschauwer
- Department of Crop Protection, Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, BE-9000, Ghent, Belgium
| | - B Gillian Turgeon
- Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, 14850, Ithaca, NY, USA
| | - Sarah De Saeger
- Department of Bio-analysis, Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University, BE-9000, Ghent, Belgium
| | - Monica Höfte
- Department of Crop Protection, Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, BE-9000, Ghent, Belgium
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Walravens J, Mikula H, Rychlik M, Asam S, Devos T, Njumbe Ediage E, Diana Di Mavungu J, Jacxsens L, Van Landschoot A, Vanhaecke L, De Saeger S. Validated UPLC-MS/MS Methods To Quantitate Free and Conjugated Alternaria Toxins in Commercially Available Tomato Products and Fruit and Vegetable Juices in Belgium. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:5101-5109. [PMID: 27180605 DOI: 10.1021/acs.jafc.6b01029] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ultraperformance liquid chromatography tandem mass spectrometry and Quick, Easy, Cheap, Effective, Rugged, and Safe based analytical methodologies to quantitate both free (alternariol (1), alternariol monomethyl ether (2), tenuazonic acid (3), tentoxin (4), altenuene (5), altertoxin-I (6)) and conjugated (sulfates and glucosides of 1 and 2) Alternaria toxins in fruit and vegetable juices and tomato products were developed and validated. Acceptable limits of quantitation (0.7-5.7 μg/kg), repeatability (RSDr < 15.7%), reproducibility (RSDR < 17.9%), and apparent recovery (87.0-110.6%) were obtained for all analytes in all matrices investigated. 129 commercial foodstuffs were analyzed, and 3 was detected in 100% of tomato product samples (<LOQ to 333 μg/kg), while 1, 2, 4, and 5 were also frequently detected (21-86%, <LOQ to 62 μg/kg). Moreover, low levels (<LOQ to 9.9 μg/kg) of modified Alternaria toxins (sulfates of 1 and 2) were repeatedly detected. A deterministic dietary exposure assessment revealed the possible risk for human health related to the presence of 1 and 2 in tomato based foodstuffs, whereas 3 is unlikely to be of human health concern.
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Affiliation(s)
- Jeroen Walravens
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University , Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Hannes Mikula
- Institute of Applied Synthetic Chemistry, Vienna University of Technology , Getreidemarkt 9, 1060 Vienna, Austria
| | - Michael Rychlik
- Chair of Analytical Food Chemistry, Technische Universität München , Alte Akademie 10, 85354 Freising, Germany
| | - Stefan Asam
- Chair of Analytical Food Chemistry, Technische Universität München , Alte Akademie 10, 85354 Freising, Germany
| | - Tom Devos
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University , Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Emmanuel Njumbe Ediage
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University , Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - José Diana Di Mavungu
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University , Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Liesbeth Jacxsens
- Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Ghent University , Coupure Links 653, 9000 Ghent, Belgium
| | - Anita Van Landschoot
- Faculty of Bioscience Engineering, Laboratory of Biochemistry and Brewing, Ghent University , Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Lynn Vanhaecke
- Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Sarah De Saeger
- Department of Bioanalysis, Laboratory of Food Analysis, Ghent University , Ottergemsesteenweg 460, 9000 Ghent, Belgium
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Development of a high performance liquid chromatography tandem mass spectrometry based analysis for the simultaneous quantification of various Alternaria toxins in wine, vegetable juices and fruit juices. J Chromatogr A 2016; 1455:74-85. [PMID: 27283097 DOI: 10.1016/j.chroma.2016.04.066] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/20/2016] [Accepted: 04/22/2016] [Indexed: 01/04/2023]
Abstract
An analytical method based on high performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS) detection for the simultaneous quantification of 12 Alternaria toxins in wine, vegetable juices and fruit juices was developed. Excellent chromatographic performance was demonstrated for tenuazonic acid (TeA) in a multi-analyte method. This comprehensive study is also the first to report the determination of TeA, alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN) and altenuene (ALT), altertoxin I (ATX-I), altertoxin II (ATX-II), altenuisol (ATL), iso-altenuene (isoALT), altenuic acid III (AA-III) and the AAL toxins TB1 und TB2 in samples from the German market. Several types of HPLC columns were tested for the liquid chromatographic separation of the toxins of interest that widely differ in their polarities. The focus was on gaining suitable retention while avoiding derivatization steps especially for TeA and AA-III. Three atmospheric pressure ionization techniques used with liquid chromatography (electrospray, chemical and photo ionization) were tested to obtain the best selectivity and sensitivity. Samples were diluted with sodium hydrogen carbonate buffer and extracted on a diatomaceous earth solid phase extraction cartridge. Method validation was carried out by using tomato juice, citrus juice and white wine as blank matrices. Limits of detection ranged from 0.10 to 0.59μgL(-1) and limits of quantification ranged from 0.4-3.1μgL(-1) depending on the toxin and matrix. Recoveries were around 100±9% for all toxins except stemphyltoxin III (STTX-III) and altenusin (ALS) due to instability during sample clean up. Matrix-induced effects leading to ion suppression especially for ATX-I, ATX-II and AA-III were investigated. Relative standard deviations of repeatability (RSDr) and intermediate reproducibility (RSDR) were ≤9.3 and ≤17.1, respectively, for the toxins in different matrices at levels of 5 and 30μgL(-1). Finally, 103 commercially obtained wine and juice samples from the German market in 2015 were analysed. TeA was found most frequently (68% of all analysed samples) in concentrations of up to 60.0μgL(-1). AOH, AME and TEN were detected in fewer samples (37%, 16% and 30%) at lower concentrations of up to 8.2, 1.5 and 10.3μgL(-1), respectively. AA-III and ATL were detected for the first time in 3% and 17% of food all samples, in concentrations of up to 6.0μgL(-1) and 5.9μgL(-1), respectively.
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Hecht ES, Oberg AL, Muddiman DC. Optimizing Mass Spectrometry Analyses: A Tailored Review on the Utility of Design of Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:767-85. [PMID: 26951559 PMCID: PMC4841694 DOI: 10.1007/s13361-016-1344-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/14/2016] [Accepted: 01/16/2016] [Indexed: 05/07/2023]
Abstract
Mass spectrometry (MS) has emerged as a tool that can analyze nearly all classes of molecules, with its scope rapidly expanding in the areas of post-translational modifications, MS instrumentation, and many others. Yet integration of novel analyte preparatory and purification methods with existing or novel mass spectrometers can introduce new challenges for MS sensitivity. The mechanisms that govern detection by MS are particularly complex and interdependent, including ionization efficiency, ion suppression, and transmission. Performance of both off-line and MS methods can be optimized separately or, when appropriate, simultaneously through statistical designs, broadly referred to as "design of experiments" (DOE). The following review provides a tutorial-like guide into the selection of DOE for MS experiments, the practices for modeling and optimization of response variables, and the available software tools that support DOE implementation in any laboratory. This review comes 3 years after the latest DOE review (Hibbert DB, 2012), which provided a comprehensive overview on the types of designs available and their statistical construction. Since that time, new classes of DOE, such as the definitive screening design, have emerged and new calls have been made for mass spectrometrists to adopt the practice. Rather than exhaustively cover all possible designs, we have highlighted the three most practical DOE classes available to mass spectrometrists. This review further differentiates itself by providing expert recommendations for experimental setup and defining DOE entirely in the context of three case-studies that highlight the utility of different designs to achieve different goals. A step-by-step tutorial is also provided.
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Affiliation(s)
- Elizabeth S Hecht
- W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Ann L Oberg
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - David C Muddiman
- W. M. Keck FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA.
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Berthiller F, Brera C, Crews C, Iha M, Krska R, Lattanzio V, MacDonald S, Malone R, Maragos C, Solfrizzo M, Stroka J, Whitaker T. Developments in mycotoxin analysis: an update for 2014-2015. WORLD MYCOTOXIN J 2016. [DOI: 10.3920/wmj2015.1998] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This review summarises developments in the determination of mycotoxins over a period between mid-2014 and mid-2015. In tradition with previous articles of this series, analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are new methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. The critical review aims to briefly discuss the most important developments and trends in mycotoxin determination as well as to address shortcomings of current methodologies.
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Affiliation(s)
- F. Berthiller
- Christian Doppler Laboratory for Mycotoxin Metabolism and Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Konrad Lorenz Str. 20, 3430 Vienna, Austria
| | - C. Brera
- Department of Veterinary Public Health and Food Safety – GMO and mycotoxins unit, ISS, Viale Regina Elena 299, 00161 Rome, Italy
| | - C. Crews
- Fera Science Ltd., Sand Hutton, York YO41 1LZ, UK
| | - M.H. Iha
- Laboratorio I de Ribeiro Preto, Instituto Adolfo Lutz, Rua Minas 877, CEP 14085-410 Ribeiro Preto-SP, Brazil
| | - R. Krska
- Christian Doppler Laboratory for Mycotoxin Metabolism and Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Konrad Lorenz Str. 20, 3430 Vienna, Austria
| | | | - S. MacDonald
- Fera Science Ltd., Sand Hutton, York YO41 1LZ, UK
| | - R.J. Malone
- Trilogy Analytical Laboratory, 870 Vossbrink Dr., Washington, MO 63090, USA
| | - C. Maragos
- USDA-ARS NCAUR, 1815 N. University St., Peoria, IL 61604, USA
| | | | - J. Stroka
- IRMM, European Commission Joint Research Centre, Retieseweg 111, 2440 Geel, Belgium
| | - T.B. Whitaker
- Biological and Agricultural Engineering Department, North Carolina State University, P.O. Box 7625, Raleigh, NC 27695-7625, USA
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López P, Venema D, de Rijk T, de Kok A, Scholten JM, Mol HG, de Nijs M. Occurrence of Alternaria toxins in food products in The Netherlands. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.07.032] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Wang M, Jiang N, Xian H, Wei D, Shi L, Feng X. A single-step solid phase extraction for the simultaneous determination of 8 mycotoxins in fruits by ultra-high performance liquid chromatography tandem mass spectrometry. J Chromatogr A 2015; 1429:22-9. [PMID: 26726936 DOI: 10.1016/j.chroma.2015.12.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/02/2015] [Accepted: 12/02/2015] [Indexed: 11/19/2022]
Abstract
A simple and rapid extraction procedure for the simultaneous determination of eight mycotoxins (Alternaria toxins, ochratoxin A, patulin, citrinin) in a variety of fruit matrices has been developed using ultra high performance liquid chromatography coupled to tandem mass spectrometry. The procedure involves a one-step cleanup using homemade solid phase extraction (SPE) cartridges. By comparative evaluation among six various adsorbents (C18, PSA, HLB, MCX, Silica, NH2), the combination of MCX and NH2 was found to provide the most effective cleanup, removing the greatest number of matrix interferences and also allowing the quantification of all analyzed mycotoxins in fruits. The optimized extraction conditions including acidified aqueous acetonitrile and an additional salt-out step using NaCl were employed before SPE cleanup. Method validation was performed by analyzing samples spiked at three levels (LOQ, 2 LOQ and 10 LOQ). Four fruits including apple, sweet cherry, tomato and orange fruits were selected, and accuracy (recovery%), precision (RSD%), limits of quantification (LOQ), linearity and matrix effect were evaluated during validation. Matrix-matched linearity with correlation coefficients ≥ 0.9921 was established in the range of 5-200 ng mL(-1) for patulin and 1-200 ng mL(-1) for other mycotoxins, respectively. Recoveries between 74.2% and 102.4% and relative standard deviations lower than 4.7% were obtained for all tested fruits. The matrix effect observed was low (≤ ± 17%) in all three fruit matrixes with the exception of orange, for which strong ion suppression was observed for alternariol (25.3%), ochratoxin A (31.6%) and citrinin (40.3%). Therefore, matrix-matched calibration was used for a correct quantification in order to compensate for matrix effect. The limits of quantification (LOQ), ranging from 1 to 5 μg kg(-1) depending on mycotoxins type, were always lower than maximum permitted levels for every regulated mycotoxin by the current European legislation.
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Affiliation(s)
- Meng Wang
- Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China; Risk Assessment Laboratory for Agro-products (Beijing), Ministry of Agriculture, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China.
| | - Nan Jiang
- Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China; Risk Assessment Laboratory for Agro-products (Beijing), Ministry of Agriculture, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China
| | - Hong Xian
- Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China; Risk Assessment Laboratory for Agro-products (Beijing), Ministry of Agriculture, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China
| | - Dizhe Wei
- Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China; Risk Assessment Laboratory for Agro-products (Beijing), Ministry of Agriculture, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China
| | - Lei Shi
- Institute of Forestry and Pomology, Beijing Academy of Agricultural and Forestry Sciences, No. 12 Ruiwangfen, Haidian Dist. Beijing, 100093, China
| | - Xiaoyuan Feng
- Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China; Risk Assessment Laboratory for Agro-products (Beijing), Ministry of Agriculture, No. 9 Middle Road of Shuguanghuayuan, Haidian Dist. Beijing, 100097, China.
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Hickert S, Bergmann M, Ersen S, Cramer B, Humpf HU. Survey of Alternaria toxin contamination in food from the German market, using a rapid HPLC-MS/MS approach. Mycotoxin Res 2015; 32:7-18. [PMID: 26408172 DOI: 10.1007/s12550-015-0233-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/17/2015] [Accepted: 09/18/2015] [Indexed: 11/25/2022]
Abstract
A HPLC-MS/MS-based method for the quantification of nine mycotoxins produced by fungi of the genus Alternaria in various food matrices was developed. The method relies on a single-step extraction, followed by dilution of the raw extract and direct analysis. In combination with an analysis time per sample of 12 min, the sample preparation is cost-effective and easy to handle. The method covers alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), altenuene (ALT), iso-altenuene (isoALT), tentoxin (TEN), altertoxin-I (ATX-I), and the AAL toxins TA1 and TA2. Some Alternaria toxins which are either not commercially available or very expensive, namely AOH, AME, ALT, isoALT, and ATX-I, were isolated as reference compounds from fungal cultures. The method was extensively validated for tomato products, bakery products, sunflower seeds, fruit juices, and vegetable oils. AOH, AME, TeA, and TEN were found in quantifiable amounts and 92.1% of all analyzed samples (n = 96) showed low level contamination with one or more Alternaria toxins. Based on the obtained results, the average daily exposure to Alternaria toxins in Germany was calculated.
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Affiliation(s)
- Sebastian Hickert
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany
- NRW Graduate School of Chemistry, Wilhelm-Klemm-Str. 10, 48149, Münster, Germany
| | - Marian Bergmann
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Seyma Ersen
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Benedikt Cramer
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany.
- NRW Graduate School of Chemistry, Wilhelm-Klemm-Str. 10, 48149, Münster, Germany.
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65
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Recent developments in stable isotope dilution assays in mycotoxin analysis with special regard to Alternaria toxins. Anal Bioanal Chem 2015; 407:7563-77. [DOI: 10.1007/s00216-015-8904-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 06/22/2015] [Accepted: 07/06/2015] [Indexed: 01/10/2023]
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66
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Tölgyesi Á, Stroka J, Tamosiunas V, Zwickel T. Simultaneous analysis of Alternaria toxins and citrinin in tomato: an optimised method using liquid chromatography-tandem mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2015; 32:1512-22. [PMID: 26212568 PMCID: PMC4673541 DOI: 10.1080/19440049.2015.1072644] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/07/2015] [Indexed: 10/25/2022]
Abstract
Alternaria toxins and citrinin are mycotoxins produced by fungi growing on different raw materials and agricultural commodities. Maximum levels of these toxins in foods are currently under consideration by the European Commission as a risk management measure. In this study, a new quantitative method is described for the determination of five Alternaria toxins and citrinin in tomato and tomato juice samples based on LC-MS/MS detection. Samples were extracted with pure methanol, followed by a derivatisation step with 2,4-dinitrophenylhydrazine to improve the determination of tenuazonic acid and to decrease the wide polarity difference between the compounds of interest. Samples were purified on hydrophilic-modified styrene polymer solid-phase extraction cartridges. High-performance liquid chromatographic columns packed with different core-shell materials were tested for the separation of toxins and a C-18 phase was in the final method applied to achieve sufficient separation of all relevant analytes. A key element of this approach was to prove successful transferability of the method to three different triple quadrupole mass spectrometers. A full single laboratory method validation was performed on two LC-MS/MS systems and performance characteristics met the predefined requirements. Moreover, the method was used in an international proficiency test and the satisfactory z-scores obtained (-0.1 to 0.8 in tomato juice samples) demonstrated the reliability of the approach described. The method will be validated in an inter-laboratory collaborative study and if the criteria for method precision are met, the method will be proposed as a new Work Item to the European Committee for Standardisation.
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Affiliation(s)
- Ádám Tölgyesi
- European Commission, Directorate-General Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - Joerg Stroka
- European Commission, Directorate-General Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
| | - Vytautas Tamosiunas
- European Commission, Directorate-General Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium
- National Food and Veterinary Risk Assessment Institute, Vilnius, Lithuania
| | - Theresa Zwickel
- BfR Federal Institute for Risk Assessment, Department of Safety in the Food Chain, Berlin, Germany
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67
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Hildebrand AA, Kohn BN, Pfeiffer E, Wefers D, Metzler M, Bunzel M. Conjugation of the mycotoxins alternariol and alternariol monomethyl ether in tobacco suspension cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:4728-36. [PMID: 25912034 DOI: 10.1021/acs.jafc.5b00806] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The mycotoxins alternariol (AOH) and alternariol-9-O-methyl ether (AME) carry three and two phenolic hydroxyl groups, respectively, which makes them candidates for the formation of conjugated metabolites in plants. Such conjugates may escape routine methods of analysis and have therefore been termed masked or, more recently, modified mycotoxins. We report now that AOH and AME are extensively conjugated in suspension cultures of tobacco BY-2 cells. Five conjugates of AOH were identified by MS and NMR spectroscopy as β-D-glucopyranosides (attached in AOH 3- or 9-position) as well as their 6'-malonyl derivatives, and as a gentiobiose conjugate. For AME, conjugation resulted in the d-glucopyranoside (mostly attached in the AME 3-position) and its 6'- and 4'-malonyl derivatives. Pronounced differences were noted for the quantitative pattern of AOH and AME conjugates as well as for their phytotoxicity. Our in vitro study demonstrates for the first time that masked mycotoxins of AOH and AME can be formed in plant cells.
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Affiliation(s)
- Andreas A Hildebrand
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Beate N Kohn
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Erika Pfeiffer
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Daniel Wefers
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Manfred Metzler
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Mirko Bunzel
- Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
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