Honors Projects


Ellen DavisFollow


With the ever-growing crisis of antibiotic resistant bacteria, bacteriophage provide an important potential alternative therapy to treat infections when antibiotics are ineffective. For this reason, it is important to understand the mechanisms bacteriophage use to enter their bacterial host cell. The cellular envelope of the gram-negative bacterium E. coli contains a protein system known as Tol-Pal, which utilizes energy from the Proton Motive Force to carry out several cellular functions, including some associated with cellular division and outer-membrane stability. Certain bacteriophage take advantage of the energy produced by this system to cross the bacterial cell membrane. One important protein of the Tol-Pal system is TolA, which may be utilized as a bacteriophage receptor. This project sought to use genetically engineered strains of E. coli with deletions of the gene associated with the production of the TolA protein to identify bacteriophage which seem to be TolA reliant. Throughout the course of this project, several bacteriophage were identified which seemed to be inhibited by the deletion of the TolA gene, although their ability to lyse the bacterial cell was not entirely lost. This may indicate that certain bacteriophage within the population of TolA reliant phage developed a gain-of-function mutation which allowed them to utilize an alternative receptor to enter the host cell.


Biological Sciences



First Advisor

Dr. Ray Larsen

First Advisor Department

Biological Sciences

Second Advisor

Dr. Craig Zirbel

Second Advisor Department

Mathematics and Statistics

Publication Date

Spring 4-25-2022