Date of Graduation

5-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Physics (PhD)

Degree Level

Graduate

Department

Physics

Advisor/Mentor

Kumar, Pradeep

Committee Member

Lewis, Jeffrey A.

Second Committee Member

Shew, Woodrow L.

Keywords

Escherichia coli; Extreme environment; Extremophile; Microorganism; Saccharomyces cerevisiae

Abstract

Organisms are known to be able to prosper under normal and extreme environmental conditions, which are classified as mesophile and extremophile, respectively. Extremophiles can thrive under a large array of conditions, from pressures, temperatures, salinity, and pH to a combination of them. For example, to survive on the ocean floor, marine biomass must have its biomolecular machinery adapted to the high pressures and high salinity environment. Moreover, around the hydrothermal vents, aside from pressure and salinity, the microbes that live there also need to adjust to the temperature as well as the pH level. Aside from high temperatures, researchers also discovered microbes that can survive up to $-80^o$C without getting their internal tissue frozen due to the extreme temperature. Even though these discoveries shed some light on the variety of extremophiles, they needed to provide a deeper understanding of the adaptation of these organisms to their environments. In order to have a better perspective on the adaptation of extremophiles, one should consider investigating the impact of extreme environmental conditions on mesophilic organisms. The extreme environment can lead to stress on mesophilic organisms, which can result in cellular arrest or cell death. However, if the changes in the environment happen slowly and not drastic change, these mesophilic organisms will be able to adapt to the new environment. These adapted organisms can be used to understand better the effect of extreme conditions on the cellular processes of mesophilic organisms and can also be the bridge to explain the metabolic processes of extremophiles. We have studied how high pressure and temperature affect the binding of RNA polymerase to recA at the transcription initiation, which provides insight into how transcription would take place in an extreme environment. Next, we studied the effect of hypersalinity environment on simple bacteria, \textit{Escherichia coli}. Finally, we examined how high pressure and salinity influence the model prokaryote, \textit{Saccharomyces cerevisiae}. The results presented here can be used as evidence to determine extraterrestrial lifeforms that may exist in our solar system, where we know that there is a presence of water.

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