Date of Completion

Spring 4-27-2018

Thesis Advisor(s)

Marcy Balunas

Honors Major

Molecular and Cell Biology


Medicinal Chemistry and Pharmaceutics | Microbiology


Bacterial and fungal strains are growing resistance to antibiotics and antifungal agents at an alarming rate. According to the Centers for Disease Control and Prevention, over two million people in the United States in 2016 were diagnosed with an infection resistant to antibiotics. As such, there has been increased interest in natural products as sources of novel compounds that are essential to the development of new drugs and treatment methods. Within the environment, there are various host-microbe symbioses, one of which is the Trachymyrmex septentrionalis leaf-cutter ant community. The microbes in symbioses like the T. septentrionalis community are hypothesized to possess the capacity to produce antimicrobial metabolites. Through the activation of silent biosynthetic gene clusters, these organisms can be induced to produce these metabolites which can then be isolated for potential drug discovery.

Following initial screening of fungus garden bacterial extracts from a T. septentrionalis community, two bioactive strains, Pseudomonas fluorescens and Delftia tsuruhatensis, were selected for continued investigation. Both strains were isolated from a colony collected from Long Island, NY and both were cultured, extracted, and tested in a suite of antimicrobial assays. Chromatographic and spectroscopic techniques were utilized to isolate and identify the predominant biologically active compounds within each bacterial extract. Additional experiments were completed in attempts to induce biosynthetic gene clusters to cause production of antimicrobial compounds. The compounds with selective antimicrobial activity and correspondingly low toxicity were prioritized as potential leads for novel antibacterial drugs.