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Thesis
Isolation of Bacteria Catalyzing Aristolochic Acid Biodegradation
University of West Florida Libraries
Master of Science (MS), University of West Florida
Spring 2022
Abstract
Aristolochia is a genus of herbaceous twining vine found in tropical and sub-tropical regions worldwide. For centuries, these plants have been used in traditional medicine to treat various infirmities. Unfortunately, aristolochic acids (AA), toxic nitro phenanthrene carboxylic acids, are produced by many species of Aristolochia. AA are activated by key enzymes in the liver and kidney causing the irreversible formation of AA-DNA adducts, which serve as biomarkers of AA-induced disease or toxicity. Accumulation of AA-DNA adducts leads to acute kidney injury, end-stage renal failure, and urothelial carcinomas collectively referred to as aristolochic acid nephropathy (AAN). Humans with confirmed AA-adduct biomarkers in their tissues are known to exist in AAN patients in China, Taiwan, Japan, South Korea, and the Balkans. Although a great deal is known about mammalian toxicology and metabolism of AA, their biodegradation has not been reported. We used selective enrichment to isolate bacteria able to biodegrade AA from 3 species of Aristolochia. Isolates in various genera including Pseudomonas, Bradyrhizobium, Pedobacter, and Variovorax species grew on aristolochic acid as the sole source of carbon, nitrogen, and energy. Accumulation of nitrite in the bacterial cultures indicated the initial attack on the molecule involves an oxygenase catalyzed elimination of the nitro group. Transient accumulation of a denitrated early metabolite provides additional evidence for the oxidative pathway rather than the alternative reductive mechanism. The diversity of the isolates suggests that they are opportunistic rather than involved in a close symbiotic relationship with the plants. The discovery of bacteria able to degrade AA suggests the potential for the elimination of the AA and thus the toxicity during submerged fermentation of plant tissue catalyzed by the bacterial isolates. The molecular details of the catabolic pathway and the potential for application in detoxification are under investigation.
Details
- Title
- Isolation of Bacteria Catalyzing Aristolochic Acid Biodegradation
- Resource Type
- Thesis
- Contributors
- Jim C Spain (Advisor)Lisa Waidner (Committee Member)Wade Jeffrey (Committee Member)
- Publisher
- University of West Florida Libraries
- Format
- pdf
- Number of pages
- 45
- Copyright
- Permission granted to the University of West Florida Libraries to digitize and/or display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires the permission of the copyright holder.
- Identifiers
- 99380090595906600
- Academic Unit
- Biology; Hal Marcus College of Science and Engineering
- Language
- English
- Awarding Institution
- University of West Florida; Master of Science (MS)
- Theses and Dissertations
- Master of Science (MS), University of West Florida