The increasing diversity of newly designed chemicals creates a potential risk for ecosystems. Efficient methods are required to generate information about their toxicological effects and molecular mechanisms.

My Ph.D. project goal is an image-based high-content screening method to assess chemical toxicity in the model species Daphnia magna. Using sensitive, non-invasive fluorescence microscopy coupled to image analysis to investigate toxicological mechanism in vivo, enables a fast and better understanding of effects.

A selection from Stockholm University publication database

• Automated Image-Based Fluorescence Screening of Mitochondrial Membrane Potential in Daphnia magna: An Advanced Ecotoxicological Testing Tool

  2024. Cedric Abele (et al.). Environmental Science and Technology 58 (36), 15926-15937

  Article

  This study demonstrated the strengths of invivo molecular staining coupled with automated imaging analysis in Daphnia magna. A multiwell plate protocol was developed to assess mitochondrial membrane potential using the JC-1 dye. The suitability of five common anesthetics was initially tested, and 5% ethanol performed best in terms of anesthetic effects and healthy recovery. The staining conditions were optimized to 30min staining with 2 μM JC-1 for best J-aggregate formation. The protocol was validated with the model compound carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and used to measure the effect of four environmental contaminants, 2,4-dinitrophenol, triclosan, n-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), and ibuprofen, on mitochondrial health. Test organisms were imaged using anautomated confocal microscope, and fluorescence intensities were automatically quantified. The effect concentrations for CCCP were lower by a factor of 30 compared with the traditional OECD 202 acute toxicity test. Mitochondrial effects were also detected at lower concentrations for all tested environmental contaminants compared to the OCED 202 test. For 2,4-dinitrophenol, mitochondria effects were detectable after 2h exposure to environmentally relevant concentrations and predicted organism death was observed after 24h. The high sensitivity and time efficiency of this novel automated imaging method make it a valuable tool for advancing ecotoxicological testing.

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