Glutathione peroxidase 3 (GPx3) is the only extracellular selenoprotein (Sel) that enzymatically reduces H₂O₂ to H₂O and O₂. Two GPx3 (CqGPx3) cDNAs were characterized from crayfish Cherax quadricarinatus. The nerve cord CqGPx3a isoform encodes for a preprotein containing an N-terminal signal peptide of 32 amino acid residues, with the mature Sel region of 192 residues and a dispensable phosphorylation domain of 36 residues. In contrast, the pereiopods CqGPx3b codes for a precursor protein with 19 residues in the N-terminal signal peptide, then the mature 184 amino acid residues protein and finally a Pro-rich peptide of 42 residues. CqGPx3 are expressed in cerebral ganglia, pereiopods and nerve cord. CqGPx3a is expressed mainly in cerebral ganglia, antennulae and nerve cord, while CqGPx3b was detected mainly in pereiopods. CqGPx3a expression increases with high temperature and hypoxia; meanwhile, CqGPx3b is not affected. We report the presence and differential expression of GPx3 isoforms in crustacean tissues in normal conditions and under stress for high temperature and hypoxia. The two isoforms are tissue specific and condition specific, which could indicate an important role of CqGPx3a in the central nervous system and CqGPx3b in exposed tissues, both involved in different responses to environmental stressors.

Jellyfish, a promising source of bioactive compounds, has attracted the attention of the biotechnology sector. This research explored the antioxidant and antimutagenic properties and the genotoxicity of peptides derived from blue cannonball jellyfish (Stomolophus sp. 2) collagen hydrolysates (JCH) as potential food supplements. Firstly, JCH was fractionated into three parts based on molecular weight. Notably, the low-molecular-weight hydrolyzed fraction (<3 kDa) exhibited the highest bioactivity, with ABTS scavenging activity of 8993 ± 5.2 μmol TE/g and an antimutagenic inhibition rate against AFB₁ of 88%. This fraction remained non-genotoxic at 100 ppm, suggesting its suitability for potential applications without evidence of genotoxic damage. In addition, in silico analysis revealed 15 unique peptides in Stomolophus sp. 2 collagen hydrolysates, ten of which showed particularly promising bioactive potential. Peptides from Stomolophus sp. 2 with molecular weights under 3 kDa exhibit remarkable bioactivity and hold great promise for future research on molecular characterization and bioactive food supplements.

Jellyfish, a promising source of bioactive compounds, have attracted the attention of the biotechnology sector. This research has explored the antioxidant and antimutagenic properties, genotoxicity, and stability of peptides derived from blue cannon jellyfish (Stomolophus sp. 2) collagen hydrolysates (JCH) as potential food supplements. JCH was fractionated into three parts: F1 (molecular weight > 10 kDa), F2 (10 kDa > molecular weight > 3 kDa), and F3 (molecular weight < 3 kDa) using ultrafiltration. Notably, F3 exhibited the highest antioxidant and antimutagenic activities while remaining non-genotoxic, supporting its safety for potential applications. The function of JCH and its fractions to quench free radicals persisted even after three months at 4°C. In addition, in silico analysis revealed 15 unique peptides in Stomolophus sp. 2 collagens, ten of which showed particularly promising bioactive potential. Peptides from Stomolophus sp. 2, with molecular weight under three kDa, exhibit remarkable bioactivity , holding great promise for future research into bioactive food supplements.