Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovak Republic.
Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 842 48, Bratislava, Slovak Republic.
Antonie Van Leeuwenhoek. 2020 Oct;113(10):1479-1488. doi: 10.1007/s10482-020-01457-8. Epub 2020 Aug 6.
Aspergillus ochraceus is a soil fungus known to produce ochratoxin A, a harmful secondary metabolite. Prevention and control of fungal pathogens mostly rely on chemical fungicides, which is one of the contributing factors in the emergence of the fungal resistance, hence novel methods for fungal eradication have been extensively researched. The cold atmospheric pressure (CAP) plasma generated in ambient air has been recently applied in microbial decontamination. Here we used the diffuse coplanar surface barrier discharge in inactivation of a toxigenic strain A. ochraceus. The plasma-treated conidia and mycelium exhibited morphological changes such as ruptures and desiccation. Mycelium dehydration and changes in the chemical composition of hyphal surface accompanied plasma treatment. The growth of 26 h old mycelia were significantly restricted after 30 s of plasma treatment. The conidial vitality declined 4 logs after 180 s of plasma exposure leading to almost complete decontamination. After shorter plasma treatment of conidia, the ochratoxin A (OTA) production increased at the early stage of cultivation, but the overall level was significantly reduced compared to untreated samples after longer cultivation. Our results indicated that the fungal growth and the OTA production were significantly changed by plasma treatment and underscored CAP plasma as a promising method in the decontamination of A. ochraceus without a risk to generate strains with increased OTA production.
土曲霉是一种土壤真菌，已知其会产生赭曲霉毒素 A，这是一种有害的次级代谢物。真菌病原体的防治主要依赖于化学杀菌剂，这也是真菌耐药性出现的原因之一，因此，人们广泛研究了消灭真菌的新方法。在大气环境中产生的冷大气压（CAP）等离子体最近已被应用于微生物的消毒。在这里，我们使用扩散共面表面屏障放电来灭活产毒菌株土曲霉。等离子体处理的分生孢子和菌丝体表现出形态变化，如破裂和干燥。菌丝体脱水和菌丝表面化学成分的变化伴随着等离子体处理而发生。处理 30 秒后，26 小时龄的菌丝生长明显受到限制。经过 180 秒的等离子体暴露，孢子活力下降 4 个对数级，几乎完全消毒。在较短的等离子体处理分生孢子后，在培养的早期阶段，赭曲霉毒素 A（OTA）的产生增加，但与未处理的样品相比，在更长的培养后，整体水平明显降低。我们的结果表明，真菌的生长和 OTA 的产生都会因等离子体处理而发生显著变化，并且突出了 CAP 等离子体作为一种在不增加 OTA 产生风险的情况下对土曲霉进行消毒的有前途的方法。
