Department of Biological and Geological Sciences, Faculty of Education, Ain Shams University, Cairo, Egypt.
Department of Microbial Molecular Biology, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt.
Probiotics Antimicrob Proteins. 2018 Jun;10(2):201-209. doi: 10.1007/s12602-017-9350-2.
Aflatoxins are a large group of highly toxic, mutagenic, and carcinogenic mycotoxins produced by specific species of fungi. Potential contamination of food commodities by these compounds causes extensive damage that lead to great economic losses. This study explored the potential use of antifungal compounds, produced by Lactobacillus brevis and Lactobacillus paracasei, for growth inhibition and subsequent aflatoxin B1 production from select strains of Aspergillus flavus and Aspergillus parasiticus. Lactobacilli strains were isolated from traditional Egyptian dairy products, whereas fungal strains were isolated from infected cereal seeds. There were noticeable decreases in mycelium biomass and aflatoxin production as well. L. brevis exhibited the highest reduction of aflatoxin B1 production by A. flavus and A. parasiticus, 96.31 and 90.43%, respectively. The concentrations of amino acids of the antifungal compound produced by L. brevis were significantly higher than that produced by L. paracasei. Asparagine, glutamine, glycine, alanine, and leucine were the most concentrated amino acids for both strains. The antifungal compounds produced by L. brevis and L. paracasei were active in a wide range of pH, heat stable and inactivated by proteolytic enzymes (protease K and trypsin A). The expression of Omt-A gene that involved in the later step of aflatoxin production was evaluated by real-time PCR. There was a vigorous reduction at transcriptional level of Omt-A gene observed in A. flavus that is treated by L. brevis and L. paracasei (80 and 70%, respectively). However, the reduction of Omt-A gene observed in A. parasiticus that is treated by L. brevis and L. paracasei was 64.5 and 52%, respectively. Treating maize seeds with antifungal compounds exhibited great efficiency in controlling fungal infection and increasing seed germination. The results confirmed that lactic acid bacteria are a promising strategy to control food contamination of fermented food and dairy products.
黄曲霉毒素是一类由特定真菌物种产生的具有高毒性、致突变性和致癌性的大型真菌毒素。这些化合物可能会污染食品，造成广泛的损害，导致巨大的经济损失。本研究探讨了使用短乳杆菌和副干酪乳杆菌产生的抗真菌化合物来抑制生长，并随后抑制特定的黄曲霉和寄生曲霉产生黄曲霉毒素 B1。短乳杆菌菌株从传统的埃及乳制品中分离出来，而真菌菌株则从受感染的谷物种子中分离出来。发现菌丝体生物量和黄曲霉毒素的产生也明显减少。短乳杆菌对黄曲霉和寄生曲霉的黄曲霉毒素 B1 抑制作用最强，分别为 96.31%和 90.43%。短乳杆菌产生的抗真菌化合物的氨基酸浓度明显高于副干酪乳杆菌。天冬酰胺、谷氨酰胺、甘氨酸、丙氨酸和亮氨酸是两种菌株中最集中的氨基酸。短乳杆菌和副干酪乳杆菌产生的抗真菌化合物在 pH 值范围广泛、热稳定且被蛋白水解酶（蛋白酶 K 和胰蛋白酶 A）失活。通过实时 PCR 评估了参与黄曲霉毒素产生后期步骤的 Omt-A 基因的表达。用短乳杆菌和副干酪乳杆菌处理的黄曲霉，Omt-A 基因在转录水平上的表达明显减少（分别为 80%和 70%）。然而，用短乳杆菌和副干酪乳杆菌处理的寄生曲霉的 Omt-A 基因减少分别为 64.5%和 52%。用抗真菌化合物处理玉米种子，在控制真菌感染和提高种子发芽率方面效果显著。研究结果证实，乳酸菌是控制发酵食品和乳制品食品污染的一种很有前景的策略。
