A novel toxicity mechanism of CdSe nanoparticles to Saccharomyces cerevisiae: enhancement of vacuolar membrane permeabilization (VMP).

Cadmium selenide (CdSe) nanoparticles are implemented in a wide range of applications, but their potential risk to the ecosystem, especially to the organisms essential for the maintenance of ecosystem homeostasis, such as fungal populations, plants and bacteria, remains to be elucidated. In this study, we investigated their toxicity to one of the most important fungal model organisms, Saccharomyces cerevisiae. Growth inhibition assays revealed that the synthesized CdSe nanoparticles with the sizes of 20-30 nm had strong inhibitory effect on yeast growth (IC50=80 ppm). This toxicity was not attributed to mitochondrial dysfunction and autophagy, but was dependent on End3-mediated endocytosis, and was associated with reactive oxygen species (ROS) accumulation and an enhancement of vacuolar membrane permeabilization (VMP). These results reveal a key role of the vacuole during the interaction between CdSe nanoparticles and yeast cells.