Date of Graduation

Spring 2021


Master of Science in Biology



Committee Chair

Kyoungtae Kim


AgNPs, CdSe/ZnS, InP/ZnS, QDs, gene expression, RNA-seq, DEGs, Saccharomyces cerevisiae

Subject Categories



The primary focus of my research was to obtain global gene expression profiles of baker’s yeast exposed to sub-lethal doses of nanoparticles, such as silver nanoparticles (AgNPs), yellow- emitting CdSe/ZnS quantum dots (QDs), green-emitting CdSe/ZnS QDs, and InP/ZnS QDs, to reveal novel insights on their unique mechanisms of toxicity. Despite their diverse applications, their long-lasting effects on the environment and human health are not well understood. To assess their toxicity, I administered experiments that exposed Saccharomyces cerevisiae to a variety of nanoparticles and measured cell viability, ROS levels, and changes in gene expression. Most notably, I used RNA-sequencing (RNA-seq) to identify gene identities of differentially expressed genes (DEGs) in nanoparticle-treated cultures. I found AgNPs altered genes implicated in rRNA processing, ribosome biogenesis, cell wall/cell membrane structure, and mitochondrial functions, yellow-emitting CdSe/ZnS QDs altered genes implicated in RNA processing, translation, oxidation-reduction, transmembrane-transport, and the ETC, green- emitting QDs altered genes implicated in translation, protein metabolic processes, transmembrane transport, cellular homeostasis, and cell wall organization, and InP/ZnS QDs altered genes associated with oxidation-reduction, transmembrane-transport, metal ion homeostasis, translation, and protein compound metabolic processes. Nevertheless, I concluded that all tested nanoparticles exerted some sort of cytotoxic effect by disrupting normal cellular functions of the budding yeast.


© Cullen M. Horstmann

Open Access