Researcher ORCID Identifier
Date of Submission
Campus Only Senior Thesis
Bachelor of Arts
Antimicrobial resistance is a large problem today as microbes find new ways to evade antimicrobials. Thus, it is necessary to understand how microbes can evolve to escape these systems. Here, we use experimental evolution, genetics, and biochemistry to understand how the model Gram-positive bacterium, Bacillus subtilis, develops resistance to copper, a known antimicrobial. Copper is known to cause damage to cells through a recently discovered concept called contact killing but has been used for its antimicrobial properties for centuries, dating back to early Egyptian texts. Genome sequencing revealed that all mutants that survived on high copper concentrations had a mutation in the ppsB gene, leading to a loss of plipastatin synthetase. Plipastatin is an antibacterial compound and helps protect the bacterium from competing bacteria and fungi. In conclusion, loss of ppsB leads to a greater ability of B. subtilis to grow in increasing copper concentrations and future research will evaluate whether plipastatin is shuttling copper into the cell or changing the form of copper, including an investigation into the same B. subtilis mutant strain in a low copper concentration environment. These findings may be important in potentially identifying plipastatin as a chalkophore.
Johnson, Grace, "Plipastatin as a Potential Chalkophore: Resistance Mechanisms Against Copper in B. Subtilis" (2023). CMC Senior Theses. 3250.
Available for download on Monday, April 29, 2024
This thesis is restricted to the Claremont Colleges current faculty, students, and staff.