No abstract

Quantum Dots (QDs) are becoming more prevalent in products used in our daily lives, such as TVs and laptops, due to their unique and tunable optical properties. The possibility of using QDs as fluorescent probes in applications, such as medical imaging, has been a topic of interest for some time, but their potential toxicity and long-term effects on the environment are not well understood. In the present study, we investigated the effects of yellow CdSe/ZnS-QDs on Saccharomyces cerevisiae. We utilized growth assays, RNA-seq, reactive oxygen species (ROS) detection assays, and cell wall stability experiments to investigate the potential toxic effects of CdSe/ZnS-QDs. We found CdSe/ZnS-QDs had no negative effects on cell viability; however, cell wall-compromised cells showed more sensitivity in the presence of 10 µg/mL CdSe/ZnS-QDs compared to non-treated cells. In CdSe/ZnS-treated and non-treated cells, no significant change in superoxide was detected, but according to our transcriptomic analysis, thousands of genes in CdSe/ZnS-treated cells became differentially expressed. Four significantly differentiated genes found, including FAF1, SDA1, DAN1, and TIR1, were validated by consistent results with RT-qPCR assays. Our transcriptome analysis led us to conclude that exposure of CdSe/ZnS-QDs on yeast significantly affected genes implicated in multiple cellular processes.

No abstract

Engineered Nano Materials (ENMs) are commercially used in everyday products, including zinc sunscreens and water resistant fabrics and surfaces, but in the future, they may be used in targeted treatment of cancer, printable monitoring systems, and foldable phones. Understanding the effects of ENMs on the environment is crucial for the responsible use of these technologies. The aim of this project is to develop a standard operating procedure (SOP) for investigating the effects of ENMs on budding yeast (Saccharomyces cerevisiae). The ENMs used to develop this protocol were Ag and CdSe/ZnS. Toxicity was determined using plate assays to analyze the effect of ENMs on the growth cycle, Fun-1 staining assays to understand the effects on cell metabolism, and quantitative reverse transcriptase-based polymerase chain reaction (PCR) and RNAseq to understand the effects on genetic expression. From plate assays, doubling times, average time spent in lag phase, maximum concentrations were determined and compared between yeast grown in varying concentrations of ENMs, and a yeast grown in a control environment. Fun-1 staining determines the amount of metabolically active cells present in a treated cell culture. RNAseq and Quantitative PCR results, in expression levels of genes, are used to determine potential toxic effects of ENMs. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.