GSE99981
Next generation sequencing of Pseudomonas aeruginosa PAO1 in the presence of Copper Nanoparticles Stress
Purpose: The intensive use of metal-based nanoparticles results in their continuous release into the environment and the subsequent destroying microbial biodiversity and causing occurrence of antibiotic resistant determinants. Although previous studies have indicated that nanoparticles may be toxic to microorganisms, there is a scarcity of data available to assess the underlying molecular mechanisms of inhibitory and biocidal effects of nanoparticles on microorganisms, which is a critical gap in our comprehensive understanding of the impacts of nanoparticles on microbial ecosystems. Methods: By combining the global activated/suppressed gene profiles and detected physiological responses, we detected the microbial response to CuO NPs exposure and revealed potential mechanisms of CuO NPs on this prevalent opportunistic pathogen and environmentally relevant denitrifier. Results:Our results indicate that nanoparticles could react directly with the biological membrane, but also change gene expressions. Transmission electron microscopy (TEM) results indicate that CuO nanoparticles not only damaged the structure of the bacterial membrane but also entered the cells. Planktonic cells of P. aeruginosa are energetically compromised after exposure to a sublethal level (1 and 10 mg/L) of CuO nanoparticles. Respiration was likely inhibited as denitrification activity was severely depleted in terms of decreased transcript levels of most denitrification genes. In addition, and of high concern, bacteriophage genes were activated and it is speculated that phage mediated cell lysis. Meanwhile, CuO NP exposure induced significantly up-regulated expressions of metal resistance gene, resistance-nodulation-division, P-type ATPase efflux and cation diffusion facilitator transporters, which can form an integrated network controlling metals concentrations in the cytoplasm and periplasm P. aeruginosa. Conclusion: Based on our results, it is evident that the response of bacteria under the exposure of nanoparticles is very complex, though a clear and comprehensive understanding of the true mechanisms of inhibition or toxicity is still lacking. Our findings will provide insights on whole picture regarding the fundamental mechanisms of microbial susceptibility, tolerance and resistance to exposure of CuO NPs, as well highlight to re-estimate potential risks of CuO NP to public health and environment. Overall design: mRNA profiles of P.aeruginosa PAO1 towards CuO NPs stress were generated by next generation sequencing via Illumina 2000.