Climate change-driven warming of aquatic environments has made thermal stress an increasingly important factor influencing fish physiological homeostasis. Given their central roles in respiration and osmoregulation, gills are particularly responsive to variations in ambient temperature. Histological examination, physiological measurements, and transcriptome profiling were integrated to investigate the mechanisms associated with heat stress-induced gill injury in pikeperch (Sander lucioperca). Histological analysis revealed that exposure to 29 °C directly caused structural damage to the gills of pikeperch. Oxidative status was evaluated by measuring malondialdehyde (MDA) levels and the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). MDA accumulation was significantly enhanced under heat stress, while antioxidant enzyme activities (SOD, POD, and CAT) displayed a transient increase followed by a subsequent decline. Transcriptome profiling showed marked enrichment of the protein processing in endoplasmic reticulum pathway after heat stress, suggesting activation of endoplasmic reticulum (ER) stress in pikeperch gills. With increasing stress duration, the unfolded protein response (UPR) appeared unable to re-establish ER homeostasis, shifting ire1 and atf6 toward a pro-apoptotic state. Protein-protein interaction (PPI) analysis further highlighted hub genes potentially involved in heat stress-induced ER stress and apoptosis. TUNEL staining and western blotting collectively confirmed that heat stress triggered apoptosis in pikeperch gill tissue. Overall, this study provides new insights into the physiological and molecular responses of pikeperch gills to heat stress and enhances our understanding of thermal stress adaptation in cold-water aquaculture species under climate change.
Rumeng Zhai, Jiaxin Song, Xiumei Liu et al.· Comparative Biochemistry and...· 0 citations
The embryonic lethal abnormal vision-like (ELAVL) gene family encodes a group of conserved RNA-binding proteins involved in post-transcriptional regulation and immune function. In this study, five ELAVL family members (Lcelavl1a, Lcelavl1b, Lcelavl2, Lcelavl3, and Lcelavl4) were identified and characterized in large yellow croaker (Larimichthys crocea). The five members exhibited a progressive motif distribution pattern and typical RNA recognition motif (RRM)-fold architectures, and phylogenetic analysis confirmed their orthologous relationships with ELAVL proteins in other vertebrates, indicating that the ELAVL family is highly conserved among teleosts. Among these five members, Lcelavl1a showed significantly higher expression levels during Aeromonas hydrophila and Pseudomonas plecoglossicida infection, suggesting an important immune-related role. It was therefore selected for further functional investigation. Lcelavl1a was detected in all nine examined tissues, with the highest expression in the gonads. Following Vibrio parahaemolyticus challenge, Lcelavl1a was significantly upregulated in the head kidney, spleen, liver, and gill. Recombinant LcELAVL1a (rELAVL1a) inhibited the growth of V. parahaemolyticus, Edwardsiella tarda, and Staphylococcus aureus in a concentration-dependent manner and bound directly to all three bacterial species, indicating broad-spectrum antibacterial activity. At the cellular level, overexpression of Lcelavl1a in large yellow croaker kidney cells (PCK) elevated the basal mRNA levels of il-1β, il-6, and tnf-α, and reduced bacteria-induced cell injury. Moreover, rELAVL1a treatment improved the viability of bacteria-infected PCK cells. Taken together, these results demonstrate that LcELAVL1a functions as an immune-active protein in large yellow croaker and provide new insights into the functional diversity of the ELAVL family in teleost fish.
Jiaxin Song, Rumeng Zhai, Dianyang Zhou et al.· Fish and Shellfish Immunolog...· 0 citations
The systematic identification of the Collectin family in silver pomfret is presented and the multifunctional immune roles of PaCL-11b in defense against V. parahaemolyticus are revealed, providing a theoretical basis for the prevention and control of bacterial diseases in silver pomfret aquaculture.
Wenxiaoman Wang, Meng Xu, Yadong Xue et al.· Fish and Shellfish Immunolog...· 0 citations
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