Date of Award

5-2021

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Kirsten Monsen-Collar

Committee Member

Lee H. Lee

Committee Member

Sandra Adams

Abstract

The dynamic role of bacteriophage in different environmental areas poses important questions about viral interactions with and control of bacteria. Bacteriophage play a vital role in the evolutionary track of bacteria. The evolutionary role of bacteriophage is affected by lysogenic conversion, transduction, mediated gene transfer, and the exertion of selective pressures. The objective of this research was to determine if there were changes in growth of the bacterial host Mycobacterium smegmatis and its bacteriophage Jenika given isolated changes in environmental conditions. Growth of the host, M. smegmatis, was documented using changes in optical density and growth of one of its bacteriophages, Jenika, was documented using viral titer. Additionally, changes in bacteriophage morphology were documented using electron microscopy. There were differences in the rate of growth of Mycobacterium smegmatis among different temperatures. Specifically, the M. smegmatis culture grown at 25 C showed significantly less growth than all other temperatures. However, despite these differences, all cultures began the exponential phase at approximately hour 15 after inoculation. The titer of Jenika was also affected by temperature as a result of the host changes; it showed a shift in the time necessary to start its exponential growth. Temperatures below the standard growth temperature showed a one-hour shift in when the exponential phase started. The electron microscopy showed similar tail lengths and head diameters for isolated phage. However, given the low statistical power of the sample size, an ANOVA was not performed on the results. The electron microscopy work should be repeated in the future with the goal of obtaining measurements on a larger sample size to increase statistical power. The results presented here suggest that changes in temperature may have an effect on the growth of the bacterial host and its bacteriophage’s ability to attach to and/or infect its host.

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