Corbicula fluminea gene expression modulated by CeO₂ nanomaterials and salinity

Area of Science:

• Environmental toxicology
• Nanomaterial science
• Molecular ecotoxicology

Background:

• Cerium dioxide nanomaterials (CeO2 NMs) are increasingly used, but their environmental impact and molecular effects are understudied.
• Understanding NM behavior in complex media and multi-stress conditions is crucial for accurate risk assessment.

Purpose of the Study:

• To assess the molecular toxicity of three CeO2 NMs in Corbicula fluminea under varying salinities (1.5 and 15 psu).
• To investigate the influence of environmental factors on NM toxicity at the gene expression level.

Main Methods:

• Exposure of Corbicula fluminea to three types of CeO2 NMs for 28 days.
• RT-qPCR analysis of 12 target genes in gills and digestive glands.
• Monitoring gene expression at intermediate time points (7, 14, 21 days) in gills.

Main Results:

• Salinity significantly influenced the expression of Se-GPx and MnSOD genes.
• Exposure to CeO2 NMs altered the expression of HSP70, Se-GPx, and Trxr genes.
• Organisms showed greater molecular differences from controls at 1.5 psu, with distinct NM effects observable.

Conclusions:

• Gene expression analysis is a valuable tool for assessing NM toxicity in aquatic organisms.
• Environmental salinity and NM characteristics significantly modulate molecular responses.
• Assessing the toxicity of manufactured NMs in realistic environmental conditions is essential.