Effects of Zinc Chelators on Aflatoxin Production in Aspergillus parasiticus.
Effects of Zinc Chelators on Aflatoxin Production in Aspergillus parasiticus.
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DOI：
10.3390/toxins8060171
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发表时间：
2016-06-02
期刊：
影响因子：
4.2
通讯作者：
Linz JE
中科院分区：
文献类型：
--
作者：
Wee J;Day DM;Linz JE
锌浓度强烈影响黄曲霉毒素在实验室培养基以及食品和饲料作物中的积累。锌的存在刺激黄曲霉毒素的产生，而缺乏锌则阻碍毒素的产生。最初的研究表明锌和黄曲霉毒素生物合成之间的联系是在20世纪70年代提出的。本研究利用两种锌螯合剂N，N,N ',N ' -四（2-吡啶基甲基）乙烷-1,2-二胺（TPEN）和2,3-二巯基-1-丙磺酸（DMPS），探讨限锌对寄生曲霉黄曲霉毒素合成的影响。TPEN使黄曲霉毒素的生物合成减少了6倍，这取决于寄生在富培养基还是低培养基上。虽然我们观察到TPEN对黄曲霉毒素的产生有明显的抑制作用，但黄曲霉毒素途径基因ver-1和锌双核簇转录因子AflR的表达水平没有明显的变化。用荧光锌探针处理生长中的寄生蜂固体培养物，与对照相比，用TPEN处理的培养物的荧光强度增加，表明细胞内锌水平增加。这些数据表明，TPEN与细胞质锌结合，因此限制了真菌对锌的接触。为了研究TPEN对食品和饲料作物的影响，我们发现TPEN可以有效降低花生培养基上黄曲霉毒素的积累，而在葵花籽培养基上则没有。从应用的角度来看，这些数据为不同锌螯合剂在黄曲霉毒素频繁污染的各种食品和饲料作物中存在的生物学差异提供了依据。
Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,N′,N′-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin.