Award Date

8-1-2021

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Life Sciences

First Committee Member

Brian Hedlund

Second Committee Member

Mira Han

Third Committee Member

Jeffery Shen

Fourth Committee Member

Qing Wu

Number of Pages

132

Abstract

Candidate bacterial phylum Omnitrophota has never been isolated and is poorly understood. In this study, we explored the genomics, phylogeny, taxonomy, distribution, cell size, and predicted physiology of Omnitrophota based on 316 genomes. Phylogenomic concordance identified seven classes accommodating 144 species. Calibration of genome-based taxonomy to ribosomal SSU profiling revealed most Omnitrophota classes are prevalent in the Earth Microbiome Dataset, particularly in soils and sediments. Fluorescence-activated cell sorting and differential size filtration experiments showed ultra-small (<400 >nm) cells are common across the phylum, as are parasitism-related genes, including a conserved tight adherence (Tad) complex and ATP/ADP translocase. However, nucleotide and amino acid biosynthetic pathways are not reduced, possibly suggesting early-stage or facultative intracellular parasitism. Energy metabolism is conserved within classes, with either acetogenic Wood-Ljungdahl or diverse respiratory pathways present. Large open reading frames (>20 kb) possibly involved in cell-cell adhesion are conserved across the phylum, including the largest prokaryotic ORF predicted yet (140 kb). These results demonstrate Omnitrophota are diverse and ubiquitous, including putative syntrophs, predators, and free-living nanobacteria that encode unusual giant open-reading frames.

Keywords

Microbial ecology; Omnitrophota

Disciplines

Microbiology

File Format

pdf

File Size

34000 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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Microbiology Commons

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