Balakumaran M D, Ramachandran R, Balashanmugam P, Mukeshkumar D J, Kalaichelvan P T
Centre for Advanced Studies in Botany, School of Life Sciences, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India.
Centre for Advanced Studies in Botany, School of Life Sciences, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India.
Microbiol Res. 2016 Jan;182:8-20. doi: 10.1016/j.micres.2015.09.009. Epub 2015 Oct 3.
This study was aimed to isolate soil fungi from Kolli and Yercaud Hills, South India with the ultimate objective of producing antimicrobial nanoparticles. Among 65 fungi tested, the isolate, Bios PTK 6 extracellularly synthesized both silver and gold nanoparticles with good monodispersity. Under optimized reaction conditions, the strain Bios PTK 6 identified as Aspergillus terreus has produced extremely stable nanoparticles within 12h. These nanoparticles were characterized by UV-vis. spectrophotometer, HR-TEM, FTIR, XRD, EDX, SAED, ICP-AES and Zetasizer analyses. A. terreus synthesized 8-20 nm sized, spherical shaped silver nanoparticles whereas gold nanoparticles showed many interesting morphologies with a size of 10-50 nm. The presence and binding of proteins with nanoparticles was confirmed by FTIR study. Interestingly, the myco derived silver nanoparticles exhibited superior antimicrobial activity than the standard antibiotic, streptomycin except against Staphylococcus aureus and Bacillus subtilis. The leakage of intracellular components such as protein and nucleic acid demonstrated that silver nanoparticles damage the bacterial cells by formation of pores, which affects membrane permeability and finally leads to cell death. Further, presence of nanoparticles in the bacterial membrane and the breakage of cell wall were also observed using SEM. Thus, the obtained results clearly reveal that these antimicrobial nanoparticles could be explored as promising candidates for a variety of biomedical and pharmaceutical applications.
本研究旨在从印度南部的科利山和耶尔卡德山分离土壤真菌，最终目标是生产抗菌纳米颗粒。在测试的65种真菌中，菌株Bios PTK 6能在细胞外合成具有良好单分散性的银和金纳米颗粒。在优化的反应条件下，被鉴定为土曲霉的菌株Bios PTK 6在12小时内产生了极其稳定的纳米颗粒。这些纳米颗粒通过紫外可见分光光度计、高分辨率透射电子显微镜、傅里叶变换红外光谱、X射线衍射、能量散射X射线光谱、选区电子衍射、电感耦合等离子体发射光谱和Zetasizer分析进行了表征。土曲霉合成的银纳米颗粒尺寸为8 - 20纳米，呈球形，而金纳米颗粒呈现出许多有趣的形态，尺寸为10 - 50纳米。傅里叶变换红外光谱研究证实了蛋白质与纳米颗粒的存在及结合。有趣的是，除了对金黄色葡萄球菌和枯草芽孢杆菌外，真菌衍生的银纳米颗粒表现出比标准抗生素链霉素更强的抗菌活性。细胞内成分如蛋白质和核酸的泄漏表明，银纳米颗粒通过形成孔道破坏细菌细胞，这影响了膜的通透性，最终导致细胞死亡。此外，使用扫描电子显微镜还观察到细菌膜中存在纳米颗粒以及细胞壁的破裂。因此，所得结果清楚地表明，这些抗菌纳米颗粒有望成为各种生物医学和制药应用的候选材料。
