Date of Award

5-1-2024

Language

English

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College/School/Department

Department of Biological Sciences

Dissertation/Thesis Chair

Thomas J Begley

Committee Members

Richard P Cunningham, Andres Melendez

Subject Categories

Biology

Abstract

Catalase is found in a plethora of organisms and plays a crucial role in safeguarding cells against oxidative stress-induced damage to proteins, RNA, and DNA. Catalase catalyzed the decomposition of hydrogen peroxide (H2O2) into oxygen and water. Deficiencies in catalase have been linked to pathological conditions such as Diabetes, Alzheimer's, and Cancer, underscoring its significance in cellular health. In bacteria like Escherichia coli, catalase is encoded by two genes, KatG and KatE, both subject to regulation through transcription, translation, and post-translational modification. Our study focused on assessing the catalase activity of mutants lacking stress response genes (e.g., lexA, soxR, soxS, marA, perR, ahpC, selD, and recA) and genes involved in translational regulation (e.g., trxB, topB, iscS, selA, selB, and selD), aiming to identify novel regulators of catalase gene expression and activity. Mutants for katE, lexA, and RecA genes show significant reductions in catalase activity, highlighting their roles in maintaining cellular redox homeostasis. In the exponential phase, mutants for katE, soxS, marA, and perR genes exhibit altered catalase activity, suggesting their involvement in regulating catalase function during rapid growth. We have demonstrated that defects in transcription factors and RNA modification activity can diminish catalase activity, suggesting a complex regulatory network governing catalase levels and function. These findings support that regulation of the oxidative stress response pathways in E. coli utilizes activities that regulate translation. This research holds significance in uncovering new insights into the intricate mechanisms governing catalase regulation, which could have implications for understanding cellular physiology.

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