中文摘要：长期以来银纳米颗粒（Ag NPs）被用作抗菌剂。但是，对于这些NPs如何影响真菌细胞功能却知之甚少。先前的研究表明Ag NPs能抑制多种产霉菌毒素的丝状真菌次生代谢物的合成，这些作用与生长抑制有关，因此需要亚致死致死剂量，除了妨碍真菌生长外，还可能在环境中积累。本研究证实了20nm的柠檬酸Ag NPs，在选定的非致死剂量，抑制丝状真菌及寄生曲霉这种重要的植物病原体，合成致癌霉菌毒素及次生代谢物黄曲霉毒素B1的效果大于2倍，而不抑制真菌生长。本研究证明了Ag NPs以非致死浓度抑制真菌次生代谢物    的可行性，因此为发现以最小的健康及环境风险，有效预防霉菌毒素而定制设计的纳米颗粒提供了一个新的起点。
外文摘要：Manufactured silver nanoparticles (Ag NPs) have long been used as antimicrobials. However, little is known about how these NPs affect fungal cell functions. While multiple previous studies reveal that Ag NPs inhibit secondary metabolite syntheses in several mycotoxin producing filamentous fungi, these effects are associated with growth repression and hence need sublethal to lethal NP doses, which besides stopping fungal growth, can potentially accumulate in the environment. Here we demonstrate that citrate-coated Ag NPs of size 20 nm, when applied at a selected nonlethal dose, can in a > 2 fold inhibition of biosynthesis of the carcinogenic mycotoxin and secondary metabolite, aflatoxin B-1 in the filamentous fungus and an important plant pathogen, Aspergillus parasiticus, without inhibiting fungal growth. We also show that the observed inhibition was not due to Ag ions, but was specifically associated with the mycelial uptake of Ag NPs. The NP exposure resulted in a significant decrease in transcript levels of five aflatoxin genes and at least two key global regulators of secondary metabolism, laeA and veA, with a concomitant reduction of total reactive oxygen species (ROS). Finally, the depletion of Ag NPs, in the growth medium allowed the fungus to regain completely its ability of aflatoxin biosynthesis. Our results therefore demonstrate the feasibility of Ag NPs to inhibit fungal secondary metabolism at nonlethal concentrations, hence providing a novel starting point for discovery of custom designed engineered nanoparticles that can efficiently prevent mycotoxins with minimal risk to health and environment.
作者：Mitra, C；Gummadidala, PM；Afshinnia, K；Merrifield, RC；Baalousha, M；Lead, JR；Chanda, A；AF Mitra, Chandrani；Gummadidala, Phani M.；Afshinnia, Kamelia
作者单位：ENVIRONMENTAL SCIENCE & TECHNOLOGY
期刊名称：ENVIRONMENTAL SCIENCE & TECHNOLOGY
期刊影响因子：5.393
出版年份：2017
出版刊次：14
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