Fuente: PubMed "rice" Dev Comp Immunol. 2026 Jun 20;181:105659. doi: 10.1016/j.dci.2026.105659. Online ahead of print.ABSTRACTSalinity fluctuations represent a major environmental stressor for freshwater bivalves; however, the regulatory interplay among osmoregulation, energy metabolism, and immune responses in Hyriopsis cumingii remains poorly understood. In this study, physiological and biochemical assays, histopathological examinations, and transcriptomic analyses were integrated to comprehensively characterize the responses of H. cumingii to increasing salinity stress. Elevated salinity significantly disrupted osmotic homeostasis, as evidenced by increased hemolymph osmolality, tissue dehydration, enhanced Na+/K+-ATPase activity, and the accumulation of alanine and glutamate. Salinity stress also induced oxidative stress, as indicated by increased catalase activity and salinity-dependent alterations in superoxide dismutase activity, accompanied by progressive histological damage to the gills and hepatopancreas. Transcriptomic analyses further revealed extensive molecular reprogramming in response to salinity stress, including the enrichment of pathways associated with energy metabolism, amino acid and lipid utilization, and innate immune regulation. Notably, immune-related signaling pathways, including MAPK and NF-κB, were significantly activated, suggesting that osmotic imbalance and metabolic adjustments were closely linked to inflammatory and stress-response signaling. Collectively, these findings indicate that the response of H. cumingii to elevated salinity involves short-term compensatory mechanisms, including osmotic adjustment, metabolic remodeling, antioxidant defense, and immune activation. However, the concurrent occurrence of tissue injury and stress-associated immune signaling suggests that these responses may not constitute stable adaptation to high-salinity conditions. This study provides species-specific insights into the integrated physiological and transcriptional mechanisms underlying salinity stress responses in freshwater pearl mussels and offers a theoretical foundation for stress assessment and aquaculture management.PMID:42322792 | DOI:10.1016/j.dci.2026.105659