engleski

Effects of silver nanoparticles and silver nitrate on root proteins of tobacco (Nicotiana tabacum) plants

The small size of nanoparticles (NPs), results in unique chemical and physical characteristics and large surface area to volume ratio increases their biological activity. These properties lead to large scale production of nanomaterials, but also lead to concerns that NPs may pose a risk for human health and environment. Silver nanoparticles (AgNPs) are of particular interest because of their antibacterial and antifungal properties, which is why they are being implemented in various consumer products. The AgNPs released into the environment are prone to aggregation, oxidation and dissolution. These transformations modify their properties influencing their transport, fate and possible toxicity. Plants are the vital part of healthy ecosystem. Since they play an important role in accumulation and biodistribution of many environmentally released substances, they could be influenced by AgNPs serving as a potential pathway for AgNP-transport and bioaccumulation into food chains. Thus, any negative effects of NPs upon plant growth could cause significant changes in the ecosystem. In this study, we examined the effects of citrate-coated AgNPs and ionic silver (AgNO3) on root proteome of tobacco plants exposed to 100 µM AgNPs and AgNO3 for 7 days. Ag accumulation in root tissue was determined by ICP-MS, while the AgNPs uptake and localization was determined with TEM-EDX microscope. Two-dimensional gel electrophoresis (2-DE) and MALDI mass spectrometry were employed to reveal the changes in protein expression. After both types of treatments, similar Ag content was measured. The TEM-EDX analysis confirmed that the silver in the nanoparticulate form was taken up by the root cells and accumulated in the cell wall. Majority of the identified root proteins with differential expression were down-regulated and involved in defense and stress response in both types of treatment. Majority of these proteins were involved in response to abiotic and biotic stimuli and response to oxidative stress. Obtained results indicate that AgNPs and AgNO3 cause similar changes in the root proteome, thus indicating that dissociated Ag+ ions could be involved, along with nanoparticulate form, in AgNPs toxicity.

nanosilver ; root proteomics

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