Akbari Dana Maryam, Kordbacheh Parivash, Daei Ghazvini Roshanak, Moazeni Maryam, Nazemi Ladan, Rezaie Sasan
Division of Molecular Biology, Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Invasive Fungi Research Centre, Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
Curr Med Mycol. 2018 Sep;4(3):10-14. doi: 10.18502/cmm.4.3.170.
Aflatoxin is known as one of the most important mycotoxins threatening human life. This toxin is produced by species, which is the common cause of agricultural product contamination. The use of organic compounds has been always considered for the inhibition of fungal growth and toxin production. Regarding this, the aim of the present study was to investigate the effect of vitamin C on the rate of fungal growth, gene expression, and toxin production.
For the purpose of the study, first, ATCC15517 was cultured in Sabouraud dextrose agar medium containing vitamin C at concentrations of 200, 100, 50, 25, 12.5, 6.25, and 3.1 mg/ml and temperature of 28°C for 72 h. Then, the amount of aflatoxin produced in the presence of vitamin C was measured through high performance liquid chromatography. Finally, by extracting the DNA of the cultured samples, the gene expression level was evaluated by means of real-time polymerase chain reaction at different concentrations of vitamin C.
The results showed that mycelium deformation was started at the vitamin C concentration of 50 mg/ml, and that only fungal spores were observed at higher concentrations. The levels of total aflatoxin and its subsets, namely B, B, G, and G, in the presence of vitamin C were estimated as 5.9, 1.9, 0.2, 3.5, and 0.3 ppm, respectively. On the other hand, these values were respectively obtained as 207.5, 73.6, 4.5, 123.4, and 6 ppm in the absence of vitamin C. Measurement of the expression level of genes showed that the level of gene expression decreased to 68% and up to 81% at the vitamin C concentrations of 25 and 50 mg/ml, respectively.
This study showed that vitamin C, as a human-compatible compound, could be considered a good agent to protect agricultural products against fungal aflatoxin.
黄曲霉毒素是已知威胁人类生命的最重要霉菌毒素之一。这种毒素由某些物种产生，是农产品污染的常见原因。一直以来都在考虑使用有机化合物来抑制真菌生长和毒素产生。鉴于此，本研究的目的是探究维生素C对真菌生长速率、基因表达和毒素产生的影响。
为进行本研究，首先，将ATCC15517在含有浓度为200、100、50、25、12.5、6.25和3.1mg/ml维生素C的沙氏葡萄糖琼脂培养基中于28°C培养72小时。然后，通过高效液相色谱法测量在维生素C存在下产生的黄曲霉毒素量。最后，通过提取培养样品的DNA，在不同维生素C浓度下借助实时聚合酶链反应评估基因表达水平。
结果表明，在维生素C浓度为50mg/ml时开始出现菌丝体变形，在更高浓度下仅观察到真菌孢子。在维生素C存在下，总黄曲霉毒素及其子集B1、B2、G1和G2的水平分别估计为5.9、1.9、0.2、3.5和0.3ppm。另一方面，在不存在维生素C的情况下，这些值分别为207.5、73.6、4.5、123.4和6ppm。对基因表达水平的测量表明，在维生素C浓度为25和50mg/ml时，基因表达水平分别降至68%和高达81%。
本研究表明，维生素C作为一种与人体相容的化合物，可被视为保护农产品免受真菌黄曲霉毒素侵害的良好试剂。
