Impact of different salt concentrations on growth, biochemical composition and nutrition quality of Phaeodactylum tricornutum and Spirulina platensis.

The effects of different salt concentrations on the growth, aroma and quality parameters of P. tricornutum and S. platensis were investigated for the first time.Salt contents were 15, 25, 30 and 35‰ for the P. tricornutum and 20, 25, 30 and 35‰ for the S. platensis culture. Aroma compounds were analyzed by HS-SPME-GC/MS while the organic acid and sugar composition were studied by HPLC-PDA-RID.The main amino acids were glutamic acid (6.24-12.96 mg/100 g) and alanine (3.67-13.65 mg/100 g) while the prevailing sugars were sucrose (229-1099 mg/100 g) and glucose (192-2322 mg/100 g) in the P. tricornutum and S. platensis samples.The most prevailing aroma compound was acetic acid (113 µg/kg) in the P. tricornutum samples and heptadecane (36941 µg/kg) in the S. platensis samples.A significant reduction was found in the amount of aroma compounds, amino acids, sugars and organic acids with increasing salt concentration.The study results are valuable for producing high-quality and flavorful P. tricornutum and S. platensis products.

Changes in energy reserves and responses of some biomarkers in freshwater mussels exposed to metal-oxide nanoparticles.

In this study, responses of various biomarkers in the digestive gland and foot muscle of freshwater mussels (Unio tigridis) were investigated following exposure to Al2O3, CuO and TiO2 nanoparticles (NPs) for 14 days at different concentrations (0, 1, 3 and 9 mg NP/L). Mussels were fed on unicellular algae (Chlorella vulgaris) cultured in the laboratory. NP exposures caused significant increases (p < 0.05) in the levels of total glutathione (GSH), reduced-glutathione (rGSH), oxidized-glutathione (GSSG) and malondialdehyde (MDA) in the digestive gland. Oppositely, there were significant (p < 0.05) decreases in acetylcholinesterase activity in the foot muscles. Total energy reserves of the digestive gland and foot muscle significantly (p < 0.05) decreased, but only at the highest NP exposures. Nevertheless, NP exposures did not alter (p > 0.05) the algae filtering capacity of mussels. This study demonstrated that the biomarkers belonging to different metabolic systems responded to NP exposures, suggesting their usage in the monitoring studies for freshwater systems.