Search Results (3)

Salinity is a key environmental factor influencing the survival of aquatic organisms, and transcriptional plasticity is a crucial emergency response to environmental changes. However, most transcriptomic studies on salinity responses have not explored the expression patterns and regulatory mechanisms across different tissues. The Suminoe oyster (Crassostrea ariakensis), a sessile estuarine species that inhabits fluctuating salinity environments, provides an excellent model for studying the molecular basis of salinity response divergence. All eight tissues responded to acute salinity stresses and exhibited distinct tissue-specific expression patterns in both mRNA and long non-coding RNA (lncRNA) profiles across three salinity conditions. The hepatopancreas and striated muscle were identified as tissues specifically sensitive to hyper- and hypo-saline stress, respectively, based on the number, expression pattern, and plasticity of differentially expressed genes (DEGs). We established lncRNA-mRNA regulatory relationships that environmentally responsive lncRNAs enhanced DEGs’ expression and underpinning tissue-specific responses. Under moderate stress, the hepatopancreas and striated muscle initiated positive responses related to water transport and shell closure, respectively. Under severe stress, the hepatopancreas activated cellular resistance pathways, while the striated muscle experienced significant cell death. Our findings provide insights into lncRNA-mediated, tissue-specific environmental responses and lay the foundation for further research into the adaptive evolution of tissue-specific regulation. Full article

This study investigates the effect of a sudden change in salinity for 48 h on the digestive enzyme activity of juvenile yellowfin tuna. The treatment included a control salinity of 32‰ in natural seawater and an experimental salinity of 29‰. Acute stress experiments were carried out on 72 juvenile yellowfin tuna (646.52 ± 66.32 g) for 48 h to determine changes in digestive enzyme activity in different intestinal sections over time (0 h, 12 h, 24 h, 48 h). The activities of pepsin, trypsin, α-amylase, lipase, and chymotrypsin in the digestive organs (stomach, foregut, and pyloric ceca) of juvenile yellowfin tuna were measured. Pepsin and pancreatic protease in the experimental group were significantly lower than in the control group (p < 0.05). α-amylase showed a fluctuating trend of decreasing and then increasing, and its activity trend was pyloric ceca > foregut > stomach. The lipase activity of gastric tissues decreased at the beginning and then increased, reaching a minimum at 24 h (2.74 ± 1.99 U·g protein⁻¹). The change of lipase in the pyloric ceca and foregut was increasing and then decreasing. The lipase activity trend was pyloric ceca > foregut > stomach. The chymotrypsin showed a decreasing and increasing trend and then stabilized at 48 h with a pattern of pyloric ceca > foregut > stomach. Similarly, the gut villi morphology was not significantly altered in the acutely salinity-stressed compared to the non-salinity-stressed. This study suggests that salinity may change the digestive function of juvenile yellowfin tuna, thereby affecting fish feeding, growth, and development. On the contrary, yellowfin tuna is highly adapted to 29‰ salinity. However, excessive stress may negatively affect digestive enzyme activity and reduce fish digestibility. This study may provide a scientific basis for a coastal aquaculture water environment for yellowfin tuna farming, which may guide the development and cultivation of aquaculture. Full article

European sea bass is a marine teleost which can inhabit a broad range of environmental salinities. So far, no research has studied the physiological response of this fish to salinity challenges using modifications in skin mucus as a potential biological matrix. Here, we used a skin mucus sampling technique to evaluate the response of sea bass to several acute osmotic challenges (for 3 h) from seawater (35‰) to two hypoosmotic environments, diluted brackish water (3‰) and estuarine waters (12‰), and to one hyperosmotic condition (50‰). For this, we recorded the volume of mucus exuded and compared the main stress-related biomarkers and osmosis-related parameters in skin mucus and plasma. Sea bass exuded the greatest volume of skin mucus with the highest total contents of cortisol, glucose, and protein under hypersalinity. This indicates an exacerbated acute stress response with possible energy losses if the condition is sustained over time. Under hyposalinity, the response depended on the magnitude of the osmotic change: shifting to 3‰ was an extreme salinity change, which affected fish aerobic metabolism by acutely modifying lactate exudation. All these data enhance the current scarce knowledge of skin mucus as a target through which to study environmental changes and fish status. Full article