Date of Award
2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biological Sciences
Committee Chair
Roy D. Magnuson
Committee Member
Tatyana Sysoeva
Research Advisor
Luis R. Cruz Vera
Subject(s)
Drug resistance in microorganisms--Research, Genetic regulation, Indole, Macrolide antibiotics, Escherichia coli
Abstract
Various genes have been proposed to play a role in the action of indole, a bacterial hormone involved in biofilm and quorum sensing. Previous work found that E. coli strains carrying a macrolide-resistant mutation in the uL22 ribosomal protein reduce tna operon mRNA levels and, consequently, decrease indole production. This ribosomal mutation also increases expression of the gad regulon, a genetic unit involved in acid resistance at pH below 2. The gad regulon is involved in bacterial survival under environmental challenges, primarily regulating intracellular acid resistance, and its expression appears to depend on indole production. In this work, we work on identifying the factors regulating the gad regulon when indole production is affected. Determining these factors could lead to the identification of genetic targets to inhibit the survival of pathogenic, macrolide-resistant E. coli that may exhibit greater resistance to acidic conditions in a host’s digestive tract. I hypothesize that cis- and trans-acting genetic elements regulate genes in the gad regulon by sensing indole production or tnaCAB operon expression.
Recommended Citation
Freeman, Lea V., "Discovering the genes and molecular mechanisms involved in increasing the expression of the gad regulon in Escherichia coli resistant to macrolide antibiotics" (2026). Theses. 826.
https://louis.uah.edu/uah-theses/826