Department of Microbiology, University of Kalyani, Kalyani 741235, India.
J Hazard Mater. 2013 Sep 15;260:1073-82. doi: 10.1016/j.jhazmat.2013.07.005. Epub 2013 Jul 10.
The present study endeavours to assess the toxic effect of synthesized CdS nanoparticles (NPs) on Escherichia coli and HeLa cells. The CdS NPs were characterized by DLS, XRD, TEM and AFM studies and the average size of NPs was revealed as ∼3 nm. On CdS NPs exposure bacterial cells changed morphological features to filamentous form and damage of the cell surface was found by AFM study. The expression of two conserved cell division components namely ftsZ and ftsQ in E. coli was decreased both at transcriptional and translational levels upon CdS NPs exposure. CdS NPs inhibited proper cell septum formation without affecting the nucleoid segregation. Viability of HeLa cells declined with increasing concentration of CdS NPs and the IC₅₀ value was found to be 4 μg/mL. NPs treated HeLa cells showed changed morphology with condensed and fragmented nuclei. Increased level of reactive oxygen species (ROS) was found both in E. coli and HeLa cells on CdS NPs exposure. The inverse correlation between declined cell viabilities and elevated ROS level suggested that oxidative stress seems to be the key event by which NPs induce toxicity both in E. coli and HeLa cells.
本研究旨在评估合成的 CdS 纳米粒子 (NPs) 对大肠杆菌和 HeLa 细胞的毒性作用。通过 DLS、XRD、TEM 和 AFM 研究对 CdS NPs 进行了表征，发现 NPs 的平均尺寸约为 3nm。在 CdS NPs 暴露下，细菌细胞的形态特征发生变化，呈丝状，并且 AFM 研究发现细胞表面受损。在 CdS NPs 暴露下，大肠杆菌中两个保守的细胞分裂成分 ftsZ 和 ftsQ 的表达在转录和翻译水平上均降低。CdS NPs 抑制了适当的细胞隔膜形成，而不影响核分离。随着 CdS NPs 浓度的增加，HeLa 细胞的活力下降，IC₅₀ 值为 4μg/mL。用 NPs 处理的 HeLa 细胞表现出核浓缩和碎片化的形态变化。在 CdS NPs 暴露下，大肠杆菌和 HeLa 细胞中均发现活性氧 (ROS) 水平升高。细胞活力下降与 ROS 水平升高之间呈负相关，这表明氧化应激似乎是 NPs 诱导大肠杆菌和 HeLa 细胞毒性的关键事件。
