Speaker
Description
Saccharomyces cerevisiae is a valuable eukaryotic model for elucidating mechanisms of metal transport, accumulation, and homeostasis. In this study, we investigated the cellular response of yeast cells to oleandrin exposure, with particular emphasis on their capacity to accumulate heavy metals. Multi-elemental analysis revealed a selective and significant increase in intracellular Mn²⁺ levels upon oleandrin treatment, while the concentration of other metals (Co²⁺, Cu²⁺, Fe³⁺, Zn²⁺) remained largely unaffected. The enhanced accumulation of Mn²⁺ was shown to be dependent on the plasma membrane transporter Smf1, a member of the NRAMP family with high affinity for divalent metal ions2. The experiments demonstrated that Mn²⁺ uptake by yeast cells is rapid and dose-dependent, occurring within minutes after oleandrin exposure. Importantly, smf1Δ mutants failed to accumulate Mn²⁺, confirming the essential role of this transporter in metal uptake. Moreover, other mutants with defective manganese homeostasis (e. g., pmr1Δ, ahp1Δ) exhibited increased Mn²⁺ accumulation and aldo increased sensitivity to oleandrin, indicating that intracellular metal overload directly contributes to oleandrin cytotoxicity. Conversely, depletion of extracellular Mn²⁺ alleviated the toxic effects of oleandrin, further supporting the link between metal accumulation and oleandrin stress.
These findings demonstrate the yeast capacity to selectively accumulate metal ions under chemical stress and emphasise the key role of membrane transport systems in metal homeostasis, also highlighting the role of yeast as a model for studying biologically-mediated metal uptake, with applications in bioremediation, bioaccumulation, and toxicity assessment.