Title : Impact of metallic nanoparticles on the regulation of antioxidant gene expression in escherichia coli, bacillus cereus and staphylococcus epidermidis strains
The widespread use of nanomaterials for consumer and industrial purposes is due to their unique physicochemical and biological properties. Inorganic nanomaterials, including metallic nanoparticles (NPs), have received much attention in the past decade due to their antimicrobial properties and non-specific targeting of treated microorganisms. With the increasing use of engineering nanomaterials in various areas of life, there is a risk of their uncontrolled release into the environment and exposure of living organisms to their potentially toxic effects. The dynamic appearance of a newer range of nano-products sometimes exceeds the identified risks associated with their presence in the natural environment and thus can negatively affect living organisms, including microorganisms. Although the mode of their action on bacterial cell processes is widely studied, many issues in this field remain unexplained and are the subject of ongoing scientific debate. Metallic NPs present specific antimicrobial properties that directly affect many cellular processes. Among them, the induction of oxidative stress has been proposed as the primary toxicological effect. The generation of reactive oxygen species and their synergistic effect with NPs could alter microbial cells' defence system, affecting the activity of antioxidant enzymes, including catalase, peroxidase and superoxide dismutase. However, as there is limited data on the impact of NPs on the expression of genes encoding antioxidants and the function of their secondary molecular proteins, research on bacterial antioxidant defense systems is crucial and worth pursuing. Therefore, this study aimed to evaluate the effect of AgNPs, CuNPs, TiO2NPs and ZnONPs on the expression level of selected genes encoding antioxidant-like proteins in three reference bacterial strains: Escherichia coli, Bacillus cereus and Staphylococcus epidermidis. Additionally, the changes in the antioxidant catalytic profiles for catalase, peroxidase and superoxide dismutase were assessed and compared with the designated gene expression profiles. The obtained data revealed that all tested NPs altered the gene expression of chosen proteins and the functioning of antioxidant enzymes. The observed changes depended exclusively on the type of NPs and studied microorganisms. In general, it was determined that the exposure of bacterial cells to AgNPs, CuNPs, TiO2NPs and ZnONPs resulted in the up- regulation of studied genes, which was correlated with increased antioxidant activity. The most significant differences between transcriptional and catalytic profiles were established for peroxidase and catalase-like proteins. Furthermore, recognized modifications in bacterial molecular processes indicate a ready response to protect cells against stress caused by NPs.
Audience Take Away:
- The presented outcomes are novel and beneficial for science because data in this field is still very limited. Therefore, performed experiments are the basis for expanding research in a given area.
- A set of readily available and reproducible research methods will be provided.
- The obtained findings will provide new information about nanoparticles' biological activity on the functioning of bacterial cells. Such data can be utilized in designing new nanomaterials, taking into account their safe use.