Objectives: This study planned to determine the biological effects associated with ZnFe₂O₄-NPs exposure using Drosophila melanogaster as an in vivo model. Methods: ZnFe₂O₄-NPs were hydrothermally synthesized, and the development of offspring flies were evaluated via dietary exposure to different doses of ZnFe₂O₄-NPs (0, 200, 400, 600 μg/mL). Rhythmic behaviors of parent male flies were monitored. Results: Internalization of ZnFe₂O₄-NPs through the intestinal barrier occurred. Oral intake of ZnFe₂O₄-NPs decreased the eclosed adult numbers and perturbed the insect developmental process. In male flies, significant upregulation of HSPs and Turandot family genes was detected, accompanied by ROS reduction and suppressed antioxidant defense responses, and exposure of ZnFe₂O₄-NPs disrupted sleep patterns of males, including a reduction in sleep duration and aggravation of sleep fragmentation. Suppressed activity levels were also found after ZnFe₂O₄-NPs exposure. Significant increased expressions of circadian genes (Clk and Cyc) were detected, alongside elevation of neurotransmitter levels and related gene expressions. Conclusions: Overall, ZnFe₂O₄-NPs can perturb development process via inducing heat shock and detoxification response, and disrupted rhythmic behaviors may be attributed to elevation of neurotransmitter levels and upregulated gene expressions of circadian genes. Our findings may offer valuable insights for evaluating ecological risks of metal-based nanoparticles and suggest potential applications in developing novel pest management strategies by utilizing insect behavioral and physiological responses to nanomaterials.

This study assessed the effects and underlying mechanisms of 50 Hz extremely low-frequency electromagnetic field (ELF-EMF) on lipid metabolism and development in ire-1 mutant Caenorhabditis elegans. Lipidomic profiling revealed 87 lipids with significant alterations following ELF-EMF exposure, and Biological Pathway Analysis (BioPAN) revealed activated conversion of phosphatidylserine to phosphatidylethanolamine, enhanced dihydroceramide synthesis, and suppressed lysophosphatidylinositol to phosphatidylinositol in ire-1 worms. Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) and Enzyme-Linked Immunosorbent Assay (ELISA) methods were utilized for further verification of lipidic alterations in ire-1 worms following ELF-EMF exposure. Significant elevation of Ca²⁺ and slight enhancement of hsp-4::GFP were observed, suggesting that endoplasmic reticulum (ER) stress may be activated independently of IRE-1, with concurrent upregulation of Activating Transcription Factor (ATF) gene expressions. Developmental inhibition was observed, characterized by 22.3% reduction in body length and 28.7% decrease in brood size. The adaptive antioxidant responses were detected as evidenced by 11.0% increased superoxide dismutase activity, 18.6% enhanced total antioxidant capacity, and 53.4% decreased malondialdehyde content. In summary, 50 Hz ELF-EMF exposure can disrupt both lipid metabolism and developmental processes in ire-1 worms, inducing striking calcium homeostasis dysregulation, ER stress, and oxidative stress responses. Unfolded protein responses were suggested to be activated independently of IRE-1, possibly involving the PERK/ATF4 pathway. ELF-EMF may act as an oxidative stress-like factor to activate ER stress and adaptive antioxidant responses in ire-1 worms.