Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

Silver nanoparticles (AgNPs) have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575) in the Arabidopsis genome, followed by Ag+ (1010), heat (1374), drought (1435), salt (4133) and cold (6536). More genes were up-regulated than down-regulated in AgNPs and Ag+ (438 and 780, respectively) while cold down-regulated the most genes (4022). Responses to AgNPs were more similar to those of Ag+ (464 shared genes), cold (202), and salt (163) than to drought (50) or heat (30); the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag+, cold and salt stresses, AgNPs are a new stressor to Arabidopsis

Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

Silver nanoparticles (AgNPs) have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575) in the Arabidopsis genome, followed by Ag+ (1010), heat (1374), drought (1435), salt (4133) and cold (6536). More genes were up-regulated than down-regulated in AgNPs and Ag+ (438 and 780, respectively) while cold down-regulated the most genes (4022). Responses to AgNPs were more similar to those of Ag+ (464 shared genes), cold (202), and salt (163) than to drought (50) or heat (30); the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag+, cold and salt stresses, AgNPs are a new stressor to Arabidopsis

Application of Molecular Dynamics in Coating Ag-Conjugated Nanoparticles with Potential Therapeutic Applications

Drug delivery systems may benefit from nanoparticles synthesized using biological methods. While chemical reduction of particles is facilitated by some active compounds present in the bio-extract, other active compounds, with potential therapeutic activities, may be adsorbed onto the surface of nanoparticles. However, the mechanism of bio-based nanoparticle synthesis is still under debate. Here, we first employed a molecular dynamics (MD) approach to theoretically predict the coating of a hypothetical 4.5 nm silver nanoparticle with four selected rosemary (Rosmarinus Officinalis L.) active compounds (rosmanol, isorosmanol, carnosol, and carnosic acid). Analysis of density maps and radial distribution functions (RDF) values suggested that the examined compounds had strong hydrophobic properties and could instantaneously be adsorbed to the nanoparticle surfaces. Next, we experimentally examined the capacity of rosemary leaf extract to synthesize and coat Ag-conjugated nanoparticles. The data obtained from ultraviolet–visible spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy and X-ray powder diffraction analyses confirmed the production of spherical Ag-conjugated nanoparticles with an average size of 12-15 nm, coated with proteins, secondary metabolites and other active compounds. Since this method can predict the dynamic behavior of therapeutic compounds when they are in contact with nanoparticles, we believe it provides a valid and new avenue to designing new therapeutic nanoparticles