ROS dependent copper toxicity in Hydra-biochemical and molecular study

Area of Science:

• Environmental toxicology
• Cellular biology
• Invertebrate physiology

Background:

• Copper is an essential element but toxic to aquatic life at elevated concentrations.
• In vitro studies show copper induces oxidative stress, but in vivo effects in lower invertebrates are less understood.

Purpose of the Study:

• To investigate the in vivo effects of environmentally relevant copper concentrations on oxidative stress in Hydra magnipapillata.
• To assess copper's impact at both organismal and cellular levels.

Main Methods:

• Exposure of Hydra to sublethal copper concentrations (0.06 and 0.1 mg/L) for 24 or 48 hours.
• Measurement of intracellular reactive oxygen species (ROS) using H2-DHCFDA staining.
• Quantitative real-time PCR for antioxidant response genes, Hsp70, and FoxO.
• Comet assay for DNA damage assessment.
• Western blotting for apoptosis-related proteins (Bax, Bcl-2, caspase-3).

Main Results:

• Copper exposure significantly increased intracellular ROS production, originating from lysosomes and mitochondria.
• Dose-dependent upregulation of antioxidant genes (CAT, SOD, GPx, GST, GR, G6PD) and stress-related genes (Hsp70, FoxO) was observed.
• DNA damage was evident via comet assay, showing dose- and duration-dependency.
• Western blot analysis confirmed ROS-mediated mitochondrial cell death.
• Morphological changes, regeneration, and reproduction were affected.

Conclusions:

• Copper exposure induces significant oxidative stress and genotoxicity in Hydra.
• Hydra exhibits stress responses involving antioxidant and heat shock proteins.
• Copper-induced ROS contribute to mitochondrial cell death and impact organismal functions.