Author Date

2026-08-01

Degree Name

BS

Department

Microbiology and Molecular Biology

College

Life Sciences

Defense Date

2026-07-27

Publication Date

2026-08-04

First Faculty Advisor

Dr. Jeffrey Schachterle

First Faculty Reader

Dr. Scott Weber

Honors Coordinator

Dr. Steven Johnson

Keywords

Bacteriophage, bacterial mutants, biocontrol, electrolytes

Abstract

This Honors thesis project examines the impact of lipopolysaccharide mutations on the virulence of a bacteria susceptible to a bacteriophage suspected of using LPS structures as the basis for infection. In my prior work in the lab, I isolated a novel lytic bacteriophage against P. versatile. From host range testing performed in the lab, it is known to infect two strains of P. versatile, B422 and B35. The phage was then used to select for resistant mutants in a pool of B422 transposon mutants, and 20 phage-resistant mutants were identified. 60% of these mutants were found to have differences in genes related to LPS, specifically in sugar transferase genes that we predict are involved in construction or modification of the sugars in the outer core of the LPS structure. The project aims to determine whether gaining resistance to this bacteriophage results in lowered bacterial virulence. This was to be determined by measuring the electrolytes leaked into solution by cabbage disks inoculated with bacteria. The more electrolytes leaked into solution, the more pathogenic the bacteria could be. This data is representative of plant cell lysis; the more electrolytes measured, the more plant cells have been lysed. I measured the electrolytes released into aqueous mixture of cabbage inoculated with P.versatile mutants R2, R7, R8, and R18 over 48 hours. The LPS structures of specific mutants were also analyzed

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