农产品中交链孢类毒素形成机制及膳食暴露研究

Alternaria toxins are most important mycotoxins in agricultural products. They are usually contaminanted in cereals, fruits and related products, and bring severe toxicity to animals and human beings. Till now, toxin formation mechanisms, cumulative rule and contamination status are still not clear yet. What’s more, the contamination of masked alternaria toxins increases dietary exposure of these mycotoxins. This project aims to detect and indentify the structure of major masked alternaria toxins via high resolution mass spectrometry and compound identification technology. The masked alternaria toxins will be synthesized on the basis of the structure confirmed. This research will also illustrate that whether the masked masked alternaria toxins could be metabolized into the free alternarias by humans. On the basis of alternaria and masked alternaria, this project proposes the toxin producing investigation of major alternaria enterotoxigenic strains contaminant in cereals, including A. alternate, A. tenuassima, A. triticina, A. triticina. Furthermore, the toxin formation mechanisms cumulative change rule of alternaria and masked alternaria in cereals could be illustrated in this work. As a consequence, a primary database could be established and applied to conduct a preliminary dietary exposure risk assessment. This project will also facilitate forewarning potential toxic cereals, which could prevent cereal-poising and provide technical support for regulation and maximum limit assessment. In addition, the experience and achievements might cast new light on other natural mycotoxin studies.

交链孢毒素是农产品中常见的一类对动物和人有害的真菌毒素，主要污染谷物、水果及其制品。目前，有关交链孢毒素产毒机制、转化规律和污染状况等研究十分有限，而隐蔽型毒素的发现进一步增加了此类毒素在膳食中暴露风险。为阐明上述科学问题，本项目拟采用液相色谱串联高分辨质谱等技术识别和鉴定主要隐蔽型交链孢毒素化学结构，进而对隐蔽型交链孢毒素进行合成，研究其在人体内能否释放出游离态毒性原型。在此基础上，以不同处理条件下的谷物为研究对象，对交链孢毒素主要产毒菌株的产毒情况进行研究，明确谷物中交链孢毒素及隐蔽型毒素的形成机制及转化规律。在此基础上创建我国谷物膳食中交链孢毒素及隐蔽型交链孢毒素的污染分布基础数据库，初步探讨居民膳食暴露风险，为指导居民膳食的选择、预防中毒事件的发生及相关政策和限量标准的制定提供技术支持，为其他真菌毒素的综合研究提供创新思路。

链格孢霉菌是谷物中污染最为严重的霉菌之一，其在谷物中的污染给农牧业发展和食品安全带来巨大的隐患，也给人和动物的健康构成直接或潜在危害。本研究累计分离并鉴定出主要霉菌48株，其中Alternaria 35株。对链格孢霉菌进行产毒研究，共鉴定出9种游离态链格孢毒素AOH, AME, ALT, TEN, TeA, ALU, DMA, DMDA和ATX-I以及6种隐蔽态链格孢毒素AOH Sulfated, AME Sulfated, ALU Sulfated, DMDA Sulfated, AME glucose和TeA glucose。采用全球公共数据分析平台GNPS对链格孢霉菌的产毒通路进行分析，构建4个链格孢毒素代谢分子簇，包括毒素代谢通路1为TeA簇，ALT, AME, AOH, DHA和DMDA簇为代谢通路2，ATX-I家族为代谢通路3，TEN家族为代谢通路4，结果表明ALT, AME, AOH, DHA和DMDA具有显著的代谢相关性。开展了辐照技术对谷物中链格孢毒素的产生规律的影响研究，结果发现：紫外照射试验组和未经过紫外照射对照组产毒种类没有差别，均产毒素AOH、TEN、TeA。但是从毒素产量看，紫外照射可显著抑制TeA的产生。项目阐明了谷物中链格孢毒素及隐蔽型毒素的形成机制及代谢转化规律，在此基础上创建了链孢毒素及隐蔽型链格孢毒素数据库，并用于链格孢毒素的筛查和确证研究。本项目将为链格孢毒素的全面分析、指导居民膳食的选择、预防中毒事件的发生及相关政策和限量标准的制定提供技术支持，为其他真菌毒素的综合研究提供创新思路。