Muhsin Tawfik M, Hachim Ahmad K
Department of Biology, College of Education for Pure Sciences, University of Basra, Basra, Iraq,
World J Microbiol Biotechnol. 2014 Jul;30(7):2081-90. doi: 10.1007/s11274-014-1634-z. Epub 2014 Mar 14.
The aim of this study was to biosynthesis silver nanoparticles from the fungus Nigrospora sphaerica isolated from soil samples and to examine their activity against five human pathogenic strains of bacteria viz. Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus using disc diffusion method. The synergistic effect of silver nanoparticles in combination with commonly used antibiotic Gentamycin against the selected bacteria was also examined. The synthesized silver nanoparticles from free-cell filtrate were characterized by using UV-Vis spectrophotometer analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). UV-Vis spectrophotometer analysis showed a peak at 420 nm indicating the synthesis of silver nanoparticles, FTIR analysis verified the detection of protein capping of silver nanoparticles while SEM micrographs revealed that the silver nanoparticles are dispersed and aggregated and mostly having spherical shape within the size range between 20 and 70 nm. The synthesized silver nanoparticles exhibited a varied growth inhibition activity (15-26 mm diam inhibition zones) against the tested pathogenic bacteria. A remarkable increase of bacterial growth inhibition (26-34 mm diam) was detected when a combination of silver nanoparticles and Gentamycin was used. A significant increase in fold area of antibacterial activity was observed when AgNPs in combination with Gentamycin was applied. The synthesized silver nanoparticles produced by the fungus N. sphaerica is a promising to be used as safe drug in medical therapy due to their broad spectrum against pathogenic bacteria.
本研究的目的是利用从土壤样本中分离出的球形黑孢菌生物合成银纳米颗粒，并使用纸片扩散法检测它们对五种人类致病细菌菌株，即大肠杆菌、奇异变形杆菌、铜绿假单胞菌、伤寒沙门氏菌和金黄色葡萄球菌的活性。还检测了银纳米颗粒与常用抗生素庆大霉素联合对所选细菌的协同作用。通过紫外可见分光光度计分析、傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）对从无细胞滤液中合成的银纳米颗粒进行了表征。紫外可见分光光度计分析显示在420nm处有一个峰值，表明银纳米颗粒的合成，FTIR分析证实检测到银纳米颗粒的蛋白质封端，而SEM显微照片显示银纳米颗粒分散且聚集，大部分为球形，尺寸范围在20至70nm之间。合成的银纳米颗粒对受试致病细菌表现出不同的生长抑制活性（抑制圈直径为15 - 26mm）。当使用银纳米颗粒和庆大霉素的组合时，检测到细菌生长抑制显著增加（抑制圈直径为26 - 34mm）。当应用银纳米颗粒与庆大霉素的组合时，观察到抗菌活性的折叠面积显著增加。由球形黑孢菌产生的合成银纳米颗粒因其对致病细菌的广谱作用而有望在医学治疗中用作安全药物。
