摘要:
脱氧雪腐镰刀菌烯醇(DON)、黄曲霉毒素B1(AFB1)和玉米赤霉烯酮(ZEN)是最为常见的粮食真菌毒素，易共存于谷物产品和动物饲料中，而目前对其联合毒性的研究较少，且研究结果并不完全一致。为探究DON、AFB1和ZEN的联合毒性作用，本论文以秀丽隐杆线虫(C. elegans)为模型，分别评估了毒素混合物AFB1+DON、AFB1+ZEN、DON+ZEN和AFB1+DON+ZEN对C. elegans的生长发育(体长)和生殖能力(产卵量)的毒性作用，并用Chou-Talalay模型来判定毒素混合物的相互作用类型。研究表明，AFB1、DON和ZEN单独染毒C. elegans时，其毒作用强弱为AFB1>ZEN>DON。联合染毒时，AFB1+DON对C. elegans产生协同作用，而DON+ZEN则产生拮抗作用；AFB1+ZEN对体长(24 h)和产卵量的毒作用随着暴露浓度的增加，由弱拮抗变为协同作用，而在毒素暴露48 h后，对线虫的生长发育呈协同作用；AFB1+DON+ZEN除在EC50-24 h和EC75-24 h时对体长产生明显的毒性增强作用外，其他普遍表现出拮抗作用。由此表明，DON、AFB1和ZEN对C. elegans的联合毒性作用与剂量和时间相关。
Abstract:
Although deoxynivalenol (DON), Aflatoxin B1 (AFB1) and zearalenone (ZEN) are the most prevalent mycotoxins co-existing in grain-based foodstuffs and feeds, little is known about their combined toxicities and the published results are inconsistent. To reveal the combined toxicities of DON, AFB1 and ZEN, the toxic effects of AFB1+DON, AFB1+ZEN, DON+ZEN and AFB1+DON+ZEN on the development (body length) and reproduction (brood size) of Caenorhabditis elegans (C. elegans) were studied, respectively. And also, the types of interactions in mycotoxins combinations were determined by using Chou-Talalay model. Results showed that the toxicity of each mycotoxin alone in a decreasing order was AFB1>ZEN>DON. For the combined toxicity, AFB1+DON synergistically enhanced the toxic effects on C. elegans while DON+ZEN showed antagonism; AFB1+ZEN displayed slight antagonism at lower concentrations, gradually turned to synergism at higher doses on body length (24 h) and brood size, and after 48 h exposure, an overall synergism was shown; AFB1+DON+ZEN generally showed antagonistic effects except for the toxicity on the body length at EC50-24 h and EC75-24 h. Thus, our study indicates that the combined toxicity of DON, AFB1 and ZEN on C. elegans is in a dose-time-response manner.
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