The hypothalamic-pituitary-gonadal (HPG) axis, particularly follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh), is essential for the regulation of teleost reproduction. However, their expression dynamics and receptor distribution during gonadal development in silver pomfret remain poorly understood. This study aimed to characterize the expression profiles and cellular localization of Fshβ, Lhβ and their receptors (Fshr and Lhr) in the pituitary and gonads and to evaluate their potential roles in reproductive regulation. The different staining method and transmission electron microscopy (TEM) were used to analyse the structural changes of the pituitary gland during the reproductive season. Quantitative PCR (qPCR) and immunohistochemical (IHC) were used to detect the expression pattern of Fshβ and Lhβ. The results showed that the number of endocrine granules significantly increased before the reproductive season, and their electron density intensified. During the spawning season, the secretory granules gradually depleted, leading to the appearance of vacuolization. In the pituitary gland, the expression of fshβ in Stage IV was significantly higher in the female pituitary, but significantly higher in Stage V in the male. Fshβ and Lhβ signals were mainly located in the proximal pars distalis (PPD) and pars intermedia (PI) regions of the pituitary. In the gonad, Fshr signals were observed in the spermatogonia type A cells and Sertoli cells in testes, whereas Lhr signals were observed in spermatogonia and secondary spermatocytes in the testes. Fshr and Lhr signals were both observed in the follicle cells surrounding the oogonia and vitellogenic oocytes in the ovary of silver pomfret. The expression patterns of fshβ and fshr were essentially similar after different hormone treatments in the gonad and methyltestosterone (MT) could influence the expression of fshβ, lhβ and fshr in the testis. Taken together, our data suggest that Fshβ and Lhβ promote the development and maturation in the gonad, and Fshr and Lhr may be involved in ovary maturation and spawning.
Chun-Yang Guo, Ding-Yuan Zhang, Yi Wang et al.· Journal of Fish Biology· 0 citations
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
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
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