Defining nanoscale genetic interactions between the bacterium E. coli and engineered nanoparticles for biomedical and environmental remediation applications

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Theophraste Noussi (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Dennis LaJeunesse

Abstract: The production of engineered nanoparticles is on the rise worldwide. Engineered nanoparticles have distinct physicochemical properties which enable their utilization in a variety of sectors from Biomedicine to Environmental remediation. Engineered nanoparticles interact with biological systems potentially changing the behavior of these systems by inducing specific physiological and metabolic modifications within the exposed organisms; furthermore, these responses to engineered nanoparticles may also differ from one organism to another. While a great deal of work has been done to identify lethal/antimicrobial nanomaterials to control pathogenic microbial biofilm formation, little work has been done to study non-lethal impact of nanomaterials on microbes. Moreover, the genetic impact of this cell-nanoparticle interaction is not well understood. We have defined the transcriptional genetic response of the gram-negative bacterium Escherichia coli (E. coli) to three different engineered silica, gold, and polystyrene nanoparticles. Screening an E. coli reporter gene library that covers 70% of the E. coli genome, we have identified eights genes that are upregulated in response to nanoparticle exposure and possibly represent a common nanoparticle response mechanism. These eight genes have been verified using qRTPCR and include previously identified stress response genes (rssB, evgA, sodC,) genes encoding transports (yhdY, yhhT) and several genes with unknown function (glcC, vacJ/MlaA, cysQ). The gene ontology of the eight genes shows that metabolic pathways, signal transduction pathways, oxidative stress and protein transport systems are significantly affected in response to the three nanoparticle exposures. Interestingly, the growth curves analysis of the single gene knockout of the eight genes reveals that the exposure to nanoparticles likely increase the cell growth rate in all mutants when compared to control and no growth pattern alterations with the wild type E. coli is observed. Furthermore, only the two mutants ?sodC and ?CysQ show significant exponential growth rates compared to control. These results demonstrate that there is specific common response of E. coli to round-shaped metalloid, metal, and polymeric nanoparticles and suggest that both sodC and cysQ genes are inherent in the bacterial growth mechanism during normal growth conditions. Overall, this research will provide a better understanding of bacteria stress response as well as bacterial resistance to nanoparticle-based antibiotics and identify potential new targets for drugs given that the bacteria-nanoparticle interactions have crucial implications in public health and the environment. [This abstract may have been edited to remove characters that will not display in this system. Please see the PDF for the full abstract.]

Additional Information

Publication
Dissertation
Language: English
Date: 2023
Keywords
Bacteria, Engineered nanoparticles, Genomics
Subjects
Genomics
Escherichia coli
Nanoparticles

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