Honors College Thesis

 

Protection of Nitrosomonas europaea from Silver Nanoparticle-Induced Inhibition through a Two-Step, Magnesium-Facilitated Mechanism Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/honors_college_theses/xg94hr67w

Descriptions

Attribute NameValues
Creator
Abstract
  • The inhibitory effects of (Ag⁺) and silver nanoparticles (Ag NP) 3-5 nm in diameter (stabilized with polyvinylpyrrolidone (PVP)) and 20 nm (stabilized with citrate) on nitrification rates of the model ammonia-oxidizing bacteria (AOB) Nitrosomonas europaea were investigated. Experimental solutions contained HEPES buffer and ammonia (NH₃) in the presence and absence of 730 μM Mg²⁺. Ag⁺ showed the most inhibition, and Ag NP-induced inhibition decreased with increasing size. In each case, Mg²⁺ showed protection from nitrification inhibiton. Ag incorporated with the cells was measured by centrifuging experimental fluid, acid-digesting the cell pellet, and measuring via ICP-OES analysis for Ag-content of the digestion. Results indicated that less Ag incorporated with the cells in the presence of Mg²⁺, suggesting that Mg²⁺ inhibits the sorption of Ag to N. europaea. UV-vis spectrophotometric analysis over 25 minutes was used to observe rapid aggregation with minimal dissolution of 20 nm citrate-stabilized Ag NP in media with 730 μM Mg²⁺, and dissolution without aggregation of the Ag NP in media without Mg²⁺. This suggests that Mg²⁺ prevents Ag NP-induced nitrification inhibition of N. europaea via a two-step mechanism: Mg²⁺ induces the aggregation of Ag NP, reducing the release of Ag⁺, and prevents incorporation of Ag to cells.
License
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Non-Academic Affiliation
Rights Statement
Publisher
Peer Reviewed
Language
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items