Document Type

Honors Thesis

Publication Date

Spring 5-2017

Abstract

Mycobacteriophage (phage) are abundant viruses that infect bacteria of the genus Mycobacterium. Pathogenic species of Mycobacterium carry prophage that are hypothesized to contribute to virulence. The term “prophage” describes a dormant phage during lysogeny, which occurs when a phage genome integrates itself into the host genome. Understanding the interactions between bacterial host and prophage may improve our ability to treat disease caused by bacteria. Phage are highly diverse and are sorted into clusters based on genome sequence similarity. To determine which phage infect and form lysogens in mycobacterial fish pathogens, we applied viral dosages of phage representative of clusters A–X to lawns of M. chelonae and M. marinum. The ability for phage to infect these alternative hosts is cluster-dependent. Two phage, BPs (cluster G) and Wildcat (cluster V), infected M. chelonae the most efficiently. BPs was able to form lysogens in M. chelonae. The ability for BPs to form lysogens in M. chelonae is not surprising since its genome encodes an integrase and a repressor, and BPs is also able to form stable lysogens in its isolation host, M. smegmatis. However, despite their highly conserved genomes, Wildcat and an additional cluster V phage, EniyanLRS, display different lysogen phenotypes. Future work includes identifying genes in both Wildcat and EniyanLRS that may play a role in lysogenic maintenance and performing RNA sequencing analysis to determine how prophage affect bacterial gene expression.

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