posted on 2012-12-04, 00:00authored bySk Tofajjen Hossain, Samir Kumar Mukherjee
This Article deals with the toxicological study of synthesized
CdO nanoparticles (NPs) on Escherichia coli. Characterization of the CdO NPs was done by DLS, XRD, TEM, and
AFM studies, and the average size of NPs was revealed as 22 ±
3 nm. The NPs showed bactericidal activity against E. coli. When NPs were added at midlog phase of growth,
complete growth inhibitory concentration was found as 40 μg/mL.
Bacterial cells changed morphological features to filamentous form
with increasing CdO NPs exposure time, and thereafter resulted in
filamentation-associated clumping. From AFM study, severe damage of
the cell surface was found in CdO NPs-treated cells. CdO NPs were
found to interfere with the expression level of two conserved cell
division components, ftsZ and ftsQ, in E. coli at both transcriptional
and translational levels. Interference of CdO NPs in proper septum
formation without affecting the nucleoid segregation was also observed
in confocal micrographs. The elevated intracellular oxidative stress
due to CdO NPs exposure seems to be one of the reasons for the changes
in cell morphology and expression of division proteins in E. coli.