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Thesis
Cobamide Distribution in Winogradsky Columns Supplemented with Halogenated Environmental Contaminants
Master of Science (M.S.), Drexel University
Sep 2022
DOI:
https://doi.org/10.17918/00001357
Abstract
Halogenated contaminants have been accumulating in our environment without an efficient method of remediation since their industrial use began in the 20th century. Recently, microbes that utilize cobamide-dependent reductive dehalogenases and iron-dependent reductive defluorination to degrade these compounds have been identified. Cobamides like cobalamin and pseudocobalamin are necessary cofactors for several enzymes, including a superfamily of reductive dehalogenases, and it has also been speculated that cobamides play a role in reductive defluorination. Cobamides are biosynthesized by a relatively small subset of bacteria but can be crossfed between species. To interrogate the presence and distribution of cobamides in a fresh-water environment, we determined the distribution of cobamides in a 1L Winogradsky column using liquid chromatography mass spectrometry (LCMS). Pseudocobalamin was found in the biofilm and top layers of the column and cobalamin was found throughout. A novel method of Winogradsky column construction was developed in which sediment and water from 1-liter columns was used to construct 150 mL 'miniature' Winogradsky columns, allowing for replicated testing of several experimental conditions. These columns were supplemented with trichloroethene (TCE), perfluorooctanoic acid (PFOA), and a cobamide precursor to enrich for cobamide-utilizing halogenated compound degraders in a complex microbial community. Cobamide analysis through mass spectrometry showed a variety of effects of these contaminants on cobamide identity and concentration. This experimental set up gives us a new way to study interspecies community metabolism in complex environmental samples, with the end goal of identifying microbial degraders of environmental contaminants.
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Details
- Title
- Cobamide Distribution in Winogradsky Columns Supplemented with Halogenated Environmental Contaminants
- Creators
- Lilly Marie McQueen
- Contributors
- Joris Beld (Advisor)Amy T. Ma (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- x, 62 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Microbiology and Immunology; College of Medicine; Drexel University
- Other Identifier
- 991019135409404721