Background: Although materials with nano-sized particles have always been prevalent in nature,
lately the production and use of synthetic nanoparticles (NPs) in the industry are on the rise. This has
led to a concomitant increase in their release into the environment. In the assessment of risks posed to
human health it has emerged that plants are the potential entry points for NPs in the food chain.
Objective: The toxic effect of cerium oxide NPs (CeO2 NPs) on seed germination in Brassica nigra was
studied viz-a-viz the activity of oxidative enzymes and global proteome expression.
Method: Brassica nigra seeds were grown in the presence of different concentrations of CeO2 NPs. The
effect on the activity levels of oxidative enzymes - Superoxide Dismutase (SOD), Glutathione reductase
(GR) and Catalase (CAT) and the global proteome expression of the seeds exposed to these NPs were
Result: It was found that the levels of activities of all the oxidative enzymes were elevated to some extent,
some even up to 2.5 fold. It emerged from proteome analysis that 14 proteins spots were upregulated,
and 19 protein spots were down-regulated. Among others, 202 protein spots were completely
absent from the gels of the control, while 154 spots were absent from the gels of the NP treated sample.
Conclusion: Oxidative stress is generated in the Brassica nigra seeds and its proteome is also significantly
altered in the presence of CeO2 NPs. Thus, it can be concluded that CeO2 NPs have the potential to
cause severe damage to living cells.