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Date of Award

2018

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Rupali Datta

Committee Member 1

Stephen Techtmann

Committee Member 2

Dibyendu Sarkar

Abstract

Pharmaceuticals and personal care products, especially antibiotics, in wastewater effluents have become a widespread issue and have begun to be detected in surface and ground water systems. Several technologies exist for the attenuation and removal of antibiotics, but many are expensive to implement and require maintenance. Additionally, those technologies require additional buildings, structures, or equipment to be added to existing wastewater treatment plants, potentially creating aesthetically displeasing features in municipalities and presenting an additional significant cost to taxpayers. Alternative technologies exist, such as chemical and physical remediation, but they are expensive and difficult to maintain. Green remediation strategies, incorporating natural processes and in-situ application, have been explored to resolve contamination issues, but results vary based on organism selection. Due to its tolerance for various organic contaminants, expansive root system, ease of growth, and previous demonstration of TC removal, vetiver grass is a strong candidate for a green remediation system. Previous studies have demonstrated the ability of vetiver grass and/or its rhizospheric bacteria to transform or degrade tetracycline in closed hydroponic systems, however the exact mechanisms by which this degradation is achieved are of yet unknown. This project sought to elucidate the biochemical reactions potentially employed in TC uptake, translocation, and tolerance in vetiver grass when exposed to high concentrations of TC in hydroponic systems. Using a metabolomics approach, vetiver was determined to exhibit mild toxicity in the presence of TC due to the accumulation of reactive oxygen species likely due to known effects of TC antibiotics on the electron transport within ribosomes as well as interruption of photosynthetic systems. Vetiver appears to achieve resolution of TC-induced oxidative stress through the utilization of classical antioxidant enzymes and molecules such as glutathione-S-transferase, glutamate synthase, cysteine, proline, abscisic and ascorbic acid, and some secondary metabolites. Results of this study have indicated possible mechanisms by which the initiation of TC transformation and degradation occur and provided future research targets in the understanding of antibiotic metabolism in plants.

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