School of BioSciences, Mahatma Gandhi University, Kottayam, Kerala, India.
School of BioSciences, Mahatma Gandhi University, Kottayam, Kerala, India.
J Photochem Photobiol B. 2018 Mar;180:175-185. doi: 10.1016/j.jphotobiol.2018.02.005. Epub 2018 Feb 7.
The green synthesis of silver nanoparticles (AgNPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the light-induced extracellular synthesis of silver nanoparticles using algicolous endophytic fungus Penicillium polonicum ARA 10, isolated from the marine green alga Chetomorpha antennina. Parametric optimization, including the concentration of AgNO, fungal biomass, ratio of cell filtrate and AgNO, pH, reaction time and presence of light, was done for rapid AgNPs production. The obtained silver nanoparticles (AgNPs) were characterized by UV-Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and Transmission electron microscopy (HRTEM-EDAX). The AgNPs showed a characteristic UV-visible peak at 430 nm with an average size of 10-15 nm. The NH stretches in FTIR indicate the presence of protein molecules. The Raman vibrational bands suggest that the molecules responsible for the reduction and stability of AgNPs were extracellular proteins produced by P.polonicum. Antibacterial evaluation of AgNPs against the major foodborne bacterial pathogen Salmonella enterica serovar Typhimurium MTCC 1251, was assessed by well diffusion, Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assay. Killing kinetic studies revealed complete killing of the bacterial cells within 4 h and the bactericidal nature of synthesized nanoparticles was confirmed by fluorescent microscopy and scanning electron microscopy. Furthermore, the bactericidal studies with Transmission electron microscopy (TEM) at different time intervals explored the presence of AgNPs in the cell wall of S.Typhimurium at about 30 min and the complete bacterial lysis was found at 24 h. The current research opens an insight into the green synthesis of AgNPs and the mechanism of bacterial lysis by direct damage to the cell wall.
利用真菌等生物系统进行银纳米粒子（AgNPs）的绿色合成已经成为纳米生物技术的一个重要领域。在此，我们首次报道了从海洋绿藻 Chetomorpha antennina 中分离得到的内生真菌 Penicillium polonicum ARA 10 通过光照诱导细胞外合成银纳米粒子。通过参数优化（包括 AgNO 的浓度、真菌生物量、细胞滤液与 AgNO 的比例、pH 值、反应时间和光照的存在）来快速生产 AgNPs。通过紫外可见光谱、傅里叶变换红外（FTIR）光谱、拉曼光谱和透射电子显微镜（HRTEM-EDAX）对所得的银纳米粒子（AgNPs）进行了表征。AgNPs 在 430nm 处显示出特征紫外可见峰，平均粒径为 10-15nm。FTIR 中的 NH 伸缩表明存在蛋白质分子。拉曼振动带表明，负责还原和稳定 AgNPs 的分子是由 P.polonicum 产生的细胞外蛋白质。通过平板扩散、最小抑菌浓度（MIC）和最小杀菌浓度（MBC）测定评估 AgNPs 对主要食源性病原体鼠伤寒沙门氏菌 MTCC 1251 的抗菌作用。杀菌动力学研究表明，细菌细胞在 4 小时内完全被杀死，合成纳米粒子的杀菌性质通过荧光显微镜和扫描电子显微镜得到证实。此外，通过透射电子显微镜（TEM）在不同时间间隔进行的杀菌研究探索了 AgNPs 在 S.Typhimurium 细胞壁中的存在，大约在 30 分钟时发现 AgNPs，并在 24 小时时发现完全的细菌裂解。当前的研究为 AgNPs 的绿色合成以及通过直接破坏细胞壁导致细菌裂解的机制提供了新的见解。
