AbstractThis study describes an aptamer based assay for the mycotoxin ochratoxin A (OTA). The method is based on the use of an OTA-specific aptamer, exonuclease (Exo) III, SYBR Gold as a fluorescent probe, and a complementary strand that specifically combines with the aptamer. In the presence of OTA, the aptamer and OTA hybridize, thereby resulting in the formation of ssDNA, which is not digested by Exo III. Intense fluorescence is observed after addition of SYBR Gold (best measured at excitation/emission wavelengths of 495/540 nm). Fluorescence increases linearly with the log of the OTA concentration in the range from 8 to 1000 ng·mL−1. The detection limit is 4.7 ng·mL−1. The assay was applied to the determination of OTA in diluted [2%(v/v)] red wine, and recoveries and RSDs ranged between 93.5% and 113.8%, and between 3.2% and 5.7%, respectively. Graphical abstractIn the presence of ochratoxin A (OTA), specific combinations of aptamer and OTA may occur and result in DNA double strands being untied, which avoids being digested by Exo III. Intense fluorescence is observed after SYBR Gold addition.

中文翻译：

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基于核酸外切酶 III 的基于荧光适配体的赭曲霉毒素 A 检测

摘要本研究描述了基于适体的真菌毒素赭曲霉毒素 A (OTA) 检测。该方法基于使用 OTA 特异性适体、核酸外切酶 (Exo) III、SYBR Gold 作为荧光探针，以及与适体特异性结合的互补链。在 OTA 存在的情况下，适配体和 OTA 杂交，从而形成 ssDNA，其不被 Exo III 消化。加入 SYBR Gold 后观察到强烈的荧光（最好在 495/540 nm 的激发/发射波长下测量）。在 8 到 1000 ng·mL-1 的范围内，荧光随 OTA 浓度的对数线性增加。检测限为 4.7 ng·mL-1。该方法用于测定稀释的 [2%(v/v)] 红酒中的 OTA，回收率和 RSD 分别介于 93.5% 和 113.8% 之间以及 3.2% 和 5.7% 之间。图形摘要在赭曲霉毒素 A (OTA) 存在下，适体和 OTA 可能发生特定组合，导致 DNA 双链解开，从而避免被 Exo III 消化。添加 SYBR Gold 后观察到强烈的荧光。