Unveiling the toxicological impact of yeast vacuoles in Daphnia

Background: The spread of introduced species necessitates effective management strategies. However, the current methods have proven ineffective, thus calling for alternative solutions. Objective: In this study, we investigated the impact of yeast vacuoles on Daphnia as a potential agent for managing adult organisms, focusing on morphological analysis, cellular damage assessment, reproductive outcomes, birthing duration, and molting behaviors. By evaluating the ecological impact of vacuoles isolated from yeast, a beneficial microorganism, we discovered a new function of vacuoles as versatile nanomaterials. Results: Although vacuoles have been extensively studied in various fields, their effects on aquatic ecosystems are not fully understood. Our findings revealed a significant influence of vacuoles on the ecology of Daphnia. The morphological characteristics of yeast vacuoles were revealed by FE-SEM and NTA analysis. Treating vacuoles and vacuolar enzymes to Daphnia resulted in observable internal damage, as evidenced by increased red fluorescence indicative of cell death. Higher concentrations of vacuoles correlated with decreased green fluorescence, suggesting greater internal damage. Furthermore, Daphnia treated with vacuoles exhibited different birth rates and birthing duration. Additionally, increasing vacuole concentrations correlated with increased foreign materials on Daphnia shells after molting, suggesting external adherence of vacuoles. Conclusion: In summary, this study provides a comprehensive understanding of toxicology and microbial ecology by revealing the influence of yeast vacuoles on Daphnia physiology and behavior. It also informs environmental management and conservation strategies in aquatic ecosystems and demonstrates the potential of vacuoles as useful agents in controlling harmful fish populations.