title: Toxicity of cadmium sulfide (CdS) nanoparticles against Escherichia coli and HeLa cells.
abstract: 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.
authors.affiliation: Department of Microbiology, University of Kalyani, Kalyani 741235, India.
authors.forename: Sk Tofajjen
authors.initials: ST
authors.lastname: Hossain
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Mukherjee
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D019187:Cadmium Compounds / Q000737:chemistry / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects*; D029968:Escherichia coli Proteins / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species; D013050:Spectrometry, Fluorescence; D013440:Sulfides / Q000737:chemistry / Q000633:toxicity*; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins; D019187:Cadmium Compounds; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C068023:FtsQ protein, E coli; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; D017382:Reactive Oxygen Species; D013440:Sulfides; C034939:cadmium sulfide
keywords: Bacterial morphology; CdS nanoparticles toxicity; Cell division; HeLa cell structure; Oxidative stress