title: Zearalenone-16-O-glucoside: a new masked mycotoxin.
abstract: This paper reports the identification of a barley UDP-glucosyltransferase, HvUGT14077, which is able to convert the estrogenic Fusarium mycotoxin zearalenone into a near-equimolar mixture of the known masked mycotoxin zearalenone-14-O-β-glucoside and a new glucose conjugate, zearalenone-16-O-β-glucoside. Biocatalytical production using engineered yeast expressing the HvUGT14077 gene allowed structural elucidation of this compound. The purified zearalenone-16-O-β-glucoside was used as an analytical calibrant in zearalenone metabolization experiments. This study confirmed the formation of this new masked mycotoxin in barley seedlings as well as in wheat and Brachypodium distachyon cell suspension cultures. In barley roots, up to 18-fold higher levels of zearalenone-16-O-β-glucoside compared to the known zearalenone-14-O-β-glucoside were found. Incubation of zearalenone-16-O-β-glucoside with human fecal slurry showed that this conjugate can also be hydrolyzed rapidly by intestinal bacteria, converting the glucoside back to the parental mycotoxin. Consequently, it should be considered as an additional masked form of zearalenone with potential relevance for food safety.
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna , Konrad Lorenz Straße 24, A-3430 Tulln, Austria.
authors.forename: Maria Paula
authors.initials: MP
authors.lastname: Kovalsky Paris
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schweiger
authors.forename: Christian
authors.initials: C
authors.lastname: Hametner
authors.forename: Romana
authors.initials: R
authors.lastname: Stückler
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Muehlbauer
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Varga
authors.forename: Rudolf
authors.initials: R
authors.lastname: Krska
authors.forename: Franz
authors.initials: F
authors.lastname: Berthiller
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
mesh_terms: D000328:Adult; D001419:Bacteria / Q000378:metabolism; D058431:Brachypodium / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D005506:Food Contamination; D005960:Glucosides / Q000737:chemistry / Q000378:metabolism*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D001467:Hordeum / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D008297:Male; D064307:Microbiota; D009183:Mycotoxins / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000737:chemistry / Q000378:metabolism*; D015025:Zearalenone / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D005960:Glucosides; D009183:Mycotoxins; D010940:Plant Proteins; D015025:Zearalenone; D005964:Glucosyltransferases