Zearalenone-16-O-glucoside: A New Masked Mycotoxin
Zearalenone-16-O-glucoside: A New Masked Mycotoxin
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DOI：
10.1021/jf405627d
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发表时间：
2014-02-05
影响因子：
6.1
通讯作者：
Adam, Gerhard
中科院分区：
文献类型：
--
作者：
Paris, Maria Paula Kovalsky;Schweiger, Wolfgang;Adam, Gerhard
本文报道了大麦UDP-葡萄糖基转移酶HvUGT14077的鉴定，该酶能将雌激素镰刀菌毒素玉米赤霉烯酮转化为已知的掩蔽真菌毒素玉米赤霉烯酮-14-O-β-葡萄糖苷和新的葡萄糖结合物玉米赤霉烯酮-16-O-β-葡萄糖苷的近等摩尔混合物。利用表达HvUGT14077基因的工程酵母进行生物催化生产，可以对该化合物进行结构鉴定。将纯化的玉米赤霉烯酮-16-O-β-葡萄糖苷作为分析校正试剂用于玉米赤霉烯酮的代谢实验。这项研究证实了这种新的隐蔽真菌毒素在大麦幼苗中以及在小麦和短梗细胞悬浮培养中的形成。在大麦根中，玉米赤霉烯酮-16-O-β-葡萄糖苷的含量比已知的玉米赤霉烯酮-14-O-β-葡萄糖苷高18倍。玉米赤霉烯酮-16-O-β-葡萄糖苷与人粪便的孵育表明，这种结合物也能被肠道细菌迅速降解，将糖苷转化回亲本霉菌毒素。因此，它应该被认为是玉米赤霉烯酮的另一种掩蔽形式，可能与食品安全有关。
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-beta-glucoside and a new glucose conjugate, zearalenone-16-O-beta-glucoside. Biocatalytical production using engineered yeast expressing the HvUGT14077 gene allowed structural elucidation of this compound. The purified zearalenone-16-O-beta-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-beta-glucoside compared to the known zearalenone-14-O-beta-glucoside were found. Incubation of zearalenone-16-O-beta-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.