Trans-generational effect of cerium oxide-nanoparticles (nCeO2) on Chenopodium rubrum L. and Sinapis alba L. seeds.

Cerium oxide nanoparticles (nCeO2 ) are interesting nanomaterials due to their redox properties. Their wide application could result in unexpected consequences to environmental safety. Unlike acute toxicity, the trans-generational effects of carbohydrate-coated nCeO2 in the environment are still unknown. The main aim of this study was to investigate the effect of treating maternal plants of Chenopodium rubrum L. (red goosefoot) and Sinapis alba L. (white mustard) with uncoated (CeO2 ) and glucose-, levan-, or pullulan-coated nCeO2 (G-, L-, or P-CeO2 ) during seed germination on morphological and physiological characteristics of produced seeds in two subsequent generations. The plant response was studied by measuring germination percentage (Ger), total protein content (TPC), total phenolic content (TPhC), total antioxidative activity (TAA), and catalase (CAT) activity. Results showed that maternal effects of the different nCeO2 treatments persist to at least the second generation in seeds. Generally, C. rubrum was more sensitive to nCeO2 treatments than S. alba . The coated nCeO2 were more effective than uncoated ones in both plant species; L- and P-CeO2 were the most effective in S. alba , while CeO2 and G-CeO2 had a dominant impact in C. rubrum . Enhanced germination in all tested generations of S. alba seeds recommends nCeO2 for seed priming.

Toxicity investigation of CeO2 nanoparticles coated with glucose and exopolysaccharides levan and pullulan on the bacterium Vibrio fischeri and aquatic organisms Daphnia magna and Danio rerio.

Cerium oxide nanoparticles (nCeO2) have widespread applications, but they can be hazardous to the environment. Some reports indicate the toxic effect of nCeO2 on tested animals, but literature data are mainly contradictory. Coating of nCeO2 can improve their suspension stability and change their interaction with the environment, which can consequently decrease their toxic effects. Herein, the exopolysaccharides levan and pullulan, due to their high water solubility, biocompatibility, and ability to form film, were used to coat nCeO2. Additionally, the monosaccharide glucose was used, since it is a common material for nanoparticle coating. This is the first study investigating the impact of carbohydrate-coated nCeO2 in comparison to uncoated nCeO2 using different model organisms. The aim of this study was to test the acute toxicity of carbohydrate-coated nCeO2 on the bacterium Vibrio fischeri NRRL B-11177, the crustacean Daphnia magna, and zebrafish Danio rerio. The second aim was to investigate the effects of nCeO2 on respiration in Daphnia magna which was performed for the first time. Finally, it was important to see the relation between Ce bioaccumulation in Daphnia magna and Danio rerio and other investigated parameters. Our results revealed that the coating decreased the toxicity of nCeO2 on Vibrio fischeri. The coating of nCeO2 did not affect the nanoparticles' accumulation/adsorption or mortality in Daphnia magna or Danio rerio. Monitoring of respiration in Daphnia magna revealed changes in CO2 production after exposure to coated nCeO2, while the crustacean's O2 consumption was not affected by any of the coated nCeO2. In summary, this study revealed that, at 200 mg L-1, uncoated and carbohydrate-coated nCeO2 are not toxic for the tested organisms, however, the CO2 production in Daphnia magna is different when they are treated with coated and uncoated nCeO2. The highest production was in glucose and levan-coated nCeO2 according to their highest suspension stability. Daphnia magna (D. magna), Danio rerio (D. rerio), Vibrio fischeri (V. fischeri).

Interaction of Carbohydrate Coated Cerium-Oxide Nanoparticles with Wheat and Pea: Stress Induction Potential and Effect on Development.

: Reports about the influence of cerium-oxide nanoparticles (nCeO2) on plants are contradictory due to their positive and negative effects on plants. Surface modification may affect the interaction of nCeO2 with the environment, and hence its availability to plants. In this study, the uncoated and glucose-, levan-, and pullulan-coated nCeO2 were synthesized and characterized. The aim was to determine whether nontoxic carbohydrates alter the effect of nCeO2 on the seed germination, plant growth, and metabolism of wheat and pea. We applied 200 mgL-1 of nCeO2 on plants during germination (Ger treatment) or three week-growth (Gro treatment) in hydroponics. The plant response to nCeO2 was studied by measuring changes in Ce concentration, total antioxidative activity (TAA), total phenolic content (TPC), and phenolic profile. Our results generally revealed higher Ce concentration in plants after the treatment with coated nanoparticles compared to uncoated ones. Considering all obtained results, Ger treatment had a stronger impact on the later stages of plant development than Gro treatment. The Ger treatment had a stronger impact on TPC and plant elongation, whereas Gro treatment affected more TAA and phenolic profile. Among nanoparticles, levan-coated nCeO2 had the strongest and positive impact on tested plants. Wheat showed higher sensitivity to all treatments.