Laboratório de Micotoxinas, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, CEP 05508-000, São Paulo, SP, Brazil.
Laboratório de Micotoxinas, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, CEP 05508-000, São Paulo, SP, Brazil.
Toxicon. 2022 Apr 15;209:36-42. doi: 10.1016/j.toxicon.2022.01.008. Epub 2022 Jan 31.
Aspergillus nomiae is the most important contaminant in Brazil nut due to its high incidence in these nuts and its strong production of carcinogenic metabolites: aflatoxins (AF). Aflatoxin biosynthesis pathway in A. nomiae is poorly studied. Thus, in present investigation, aflatoxin production and gene cluster (aflC, aflQ, aflU, and aflX) expression profile were evaluated on two strains of A. nomiae isolated from Brazil nut samples collected in the Amazon region, and cultivated on Brazil nut-based medium. The results showed that the expression of the aflatoxin gene cluster in A. nomiae, started at day 2 and occurred before the production of aflatoxins. Aflatoxin production (AFB and AFG) was detected on day 3 on both strains. From day 4 onwards, all four toxins were detected and their production kept at similar proportions (AFG>AFB>AFG>AFB). Thus, the anticipated information obtained through early expression profile results of aflC, aflQ, aflU, and aflX gene cluster in A. nomiae may foresee aflatoxin production before its detection in Brazil nuts.
棘孢木霉是巴西果中最重要的污染物，因为它在这些坚果中的发生率很高，而且它能产生很强的致癌代谢物：黄曲霉毒素（AF）。棘孢木霉中黄曲霉毒素生物合成途径的研究还很不完善。因此，在目前的研究中，评估了从亚马逊地区采集的巴西果样本中分离的两株棘孢木霉在巴西果为基础的培养基上培养时的产毒和基因簇（aflC、aflQ、aflU 和 aflX）表达谱。结果表明，棘孢木霉中的黄曲霉毒素基因簇的表达始于第 2 天，并且在产生黄曲霉毒素之前发生。在这两种菌株上，均于第 3 天检测到黄曲霉毒素的产生（AFB 和 AFG）。从第 4 天开始，检测到所有四种毒素，其产生比例保持相似（AFG>AFB>AFG>AFB）。因此，通过早期棘孢木霉 aflC、aflQ、aflU 和 aflX 基因簇的表达谱结果，可以预期在巴西坚果中检测到黄曲霉毒素之前就可以预测其产生。
