Dissertation/Thesis Abstract

Conservatism of Chemosynthetic Sulfur Metabolism Functional Potential Varies Across Prokaryotes
by Yarbrough, Katherine A., M.S., California State University, Long Beach, 2020, 117; 28001058
Abstract (Summary)

Microbial oxidation and reduction processes presently impact global biogeochemical cycling of sulfur, an essential element for life. Sulfur is considered an early substrate for ancient microbial life as the evolution of sulfur metabolism predates photosynthesis. Public access databases are a wellspring of hundreds of thousands of high-quality, structurally and functionally annotated genomes. This project mined the KEGG and PATRIC databases to explore the phylogenetic distribution of sulfur oxidation and reduction traits within sequenced microbial genomes. It was hypothesized that conservatism would follow the number of genes underlying a trait (molecular complexity) and predicted that the most complex would be the most conserved. Several custom BASH language shell programs were used to gather sequence and gene count data. The previously published algorithm consenTRAIT was applied to determine trait depth (τƊ), the Fritz and Purvis test determined phylogenetic Dispersion (D, phylogenetic signal); together these metrics elucidated the levels of conservatism for four key biological sulfur cycle pathways of oxidation and reduction across phyla. Contrary to predictions, the molecularly complex Sox Sulfur Oxidation pathway is the least clumped of all traits analyzed (τƊ = 0.016, D = 0.029). The moderately molecularly complex Assimilatory and Dissimilatory Sulfur Reduction pathways match predictions based on molecular complexity (τƊ = 0.0232, D = -0.0075; τƊ = 0.039, D = -0.350). The most complex pathway, Dissimilatory Sulfur Oxidation, was deeply conserved and also matched predictions based on molecular complexity (τƊ = 0.048, D = -0.3504). The results of this work have elucidated the phylogenetic distribution and conservatism of four biological sulfur cycle pathways for sulfur metabolism across prokaryotes and how molecular complexity of trait affects both distribution and conservatism.

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Indexing (document details)
Advisor: Berlemont, Renaud, Dillon, Jesse
Commitee: Stankowich, Theodore
School: California State University, Long Beach
Department: Biological Sciences
School Location: United States -- California
Source: MAI 82/6(E), Masters Abstracts International
Subjects: Microbiology, Genetics, Bioinformatics, Molecular chemistry, Biogeochemistry, Organic chemistry
Keywords: Comparative genomics, Extreme environments, Phylogenetic signal, Sox, Sulfur metabolism, Sulfur oxidation
Publication Number: 28001058
ISBN: 9798698588313
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