Date of Award
Pharmaceutics and Drug Delivery
Opportunistic fungal infections have become problematic in recent years. There has been an emergence of new fungal pathogens, development of antifungal resistance, and increasing prevalence. In addition, toxicity, resistance, and lack of efficacy as a single agent limit the effectiveness of current antifungal drugs. Therefore, new drugs targeting new pathways are greatly needed. An analog derived from the marine natural product phloeodictine, analog PHL5-34A, was identified as having strong in vitro antifungal activity. In this study, its mechanism of action (MOA) was investigated in the model yeast, Saccharomyces cerevisiae. This study made use of a collection of 166 yeast mutants carrying deletions in transcription factors, which function as master regulators of cellular processes. Using the parent S. cerevisiae strain BY4742, a pilot experiment was conducted to determine the sub-inhibitory concentration of PHL5-34A that reduced cell growth on agar plates. After assay conditions were optimized, the mutant collection was screened to identify mutants with altered sensitivity to PHL5-34A. Of the 166 deletion mutants tested, 20 were found to be hypersensitive to PHL5-34A when compared to the parent. Drop-test assays were conducted and 10 mutants were confirmed to be hypersensitive to PHL5-34A. Of these confirmed mutants, 4 mutants were found to carry deletions in genes required for cell cycle functions. These 4 mutations were then analyzed by PCR to confirm that they were in the correct genes. This work has demonstrated that the cell cycle is one of the pathways affected by PHL5-34A, and it will serve as an important step in determining the exact MOA of this compound.
Ward, Amber, "Mechanism of Action of a Novel Antifungal Compound" (2012). Honors Theses. 58.