Department of Microbiology, CCB, State University of Londrina, Paraná, Brazil.
Department of Microbiology, CCB, State University of Londrina, Paraná, Brazil; Laboratory of Electronic Microscopy and Microanalysis, State University of Londrina, Londrina, Brazil.
Int J Food Microbiol. 2019 Feb 16;291:79-86. doi: 10.1016/j.ijfoodmicro.2018.11.012. Epub 2018 Nov 13.
Aspergillus spp. are ubiquitous fungi that grow on stored grains. Some species produce toxins that can harm human and animal health, leading to hepato- and nephrotoxicity, immunosuppression and carcinogenicity. Major fungicides used to prevent fungal growth may be toxic to humans and their repeated use over time increases levels of resistance by microorganisms. Nanotechnology is an emerging field that allows use of antimicrobial compounds in a more efficient manner. In this study, was evaluated the antifungal activity of biogenic silver nanoparticles (AgNPs, synthesized by fungi) and simvastatin (SIM, a semi-synthetic drug), alone and in combination against three toxigenic species belonging to the genera Aspergillus section Flavi (Aspergillus flavus, Aspergillus nomius and Aspergillus. parasiticus) and two of section Circumdati (Aspergillus ochraceus and Aspergillus melleus). SIM exhibited a MIC of 78 μg/mL against species of Section Flavi and a MIC of 19.5 μg/mL against species of Section Circumdati. The MIC of AgNPs against Aspergillus flavus, Aspergillus nomius and Aspergillus parasiticus was 8 μg/mL, while the MIC was 4 μg/mL against Aspergillus melleus and Aspergillus ochraceus. Checkerboard assay showed that these compounds, used alone and in combination, have synergistic and additive effects against toxicogenic species of Aspergillus. Analysis by SEM gives an idea of the effect of SIM and AgNPs alone and in combination on spore germination and vegetative growth. Ultrastructural analysis revealed that spore germination was prevented, or aberrant hyphae were formed with multilateral branches upon treatment with SIM and AgNPs. These results reveal potential benefits of using combination of AgNPs and SIM to control fungal growth.
曲霉菌属是一种普遍存在的真菌，生长在储存的谷物上。一些曲霉菌种会产生毒素，损害人类和动物的健康，导致肝和肾毒性、免疫抑制和致癌性。用于防止真菌生长的主要杀真菌剂可能对人类有毒，而且随着时间的推移，它们的重复使用会增加微生物的耐药性水平。纳米技术是一个新兴领域，可以更有效地使用抗菌化合物。在这项研究中，评估了生物合成银纳米粒子（AgNPs，由真菌合成）和辛伐他汀（SIM，一种半合成药物）单独和联合使用对属于黄曲霉节（黄曲霉、拟青霉和寄生曲霉）和两个环曲霉菌节（橘青霉和红曲霉）的三种产毒种的抗真菌活性。SIM 对黄曲霉节的种显示出 78μg/mL 的 MIC，对环曲霉菌节的种显示出 19.5μg/mL 的 MIC。AgNPs 对黄曲霉、拟青霉和寄生曲霉的 MIC 为 8μg/mL，而对红曲霉和橘青霉的 MIC 为 4μg/mL。棋盘试验表明，这些化合物单独和联合使用对产毒曲霉菌种具有协同和相加作用。扫描电镜分析提供了 SIM 和 AgNPs 单独和联合使用对孢子萌发和营养生长影响的直观认识。超微结构分析显示，单独或联合使用 SIM 和 AgNPs 可防止孢子萌发，或导致异常菌丝形成多边分支。这些结果表明，联合使用 AgNPs 和 SIM 控制真菌生长具有潜在的益处。
