The Effects of Sublethal Concentrations of Nanoparticles on E.coli Cells in Simulated Environmental Conditions
Session Number
Project ID: ENVIR 01
Advisor(s)
Kimberly A. Gray, Shushan Wu, Northwestern University
Discipline
Environmental Science
Start Date
17-4-2024 8:15 AM
End Date
17-4-2024 8:30 AM
Abstract
Engineered nanomaterials (ENMs) are widely used across commercial sectors, yet their effects on environmental systems have not been examined thoroughly, especially at environmentally relevant concentrations. They are known to be harmful at lethal doses, but their effects on natural environmental systems at sublethal doses, the examples primarily seen in real life, have only recently been studied. Previous studies have shown that ENMs like TiO2 nanoparticles (n-TiO2) and Ag nanoparticles (n-Ag) increase the outer cell membrane permeability of E.coli cells under light and exhibit amplified toxicity when mixed, making cells more vulnerable to other assaults. In this project, the sublethal effects of ENMs on bacteriophage infection of E.coli cells were investigated. For this experiment, E.coli cells were suspended in Lake Michigan Water (LMW) and exposed to different concentrations of n-TiO2 under simulated sunlight and dark before being exposed to phage f1 and phage lambda, respectively. Our results showed that low concentrations of n- TiO2 (0.1-0.5 mg/L) promoted phage f1 infection significantly under light, which could be attributed to the increased outer membrane permeability and enhanced expression of pilus-related genes.
The Effects of Sublethal Concentrations of Nanoparticles on E.coli Cells in Simulated Environmental Conditions
Engineered nanomaterials (ENMs) are widely used across commercial sectors, yet their effects on environmental systems have not been examined thoroughly, especially at environmentally relevant concentrations. They are known to be harmful at lethal doses, but their effects on natural environmental systems at sublethal doses, the examples primarily seen in real life, have only recently been studied. Previous studies have shown that ENMs like TiO2 nanoparticles (n-TiO2) and Ag nanoparticles (n-Ag) increase the outer cell membrane permeability of E.coli cells under light and exhibit amplified toxicity when mixed, making cells more vulnerable to other assaults. In this project, the sublethal effects of ENMs on bacteriophage infection of E.coli cells were investigated. For this experiment, E.coli cells were suspended in Lake Michigan Water (LMW) and exposed to different concentrations of n-TiO2 under simulated sunlight and dark before being exposed to phage f1 and phage lambda, respectively. Our results showed that low concentrations of n- TiO2 (0.1-0.5 mg/L) promoted phage f1 infection significantly under light, which could be attributed to the increased outer membrane permeability and enhanced expression of pilus-related genes.