Suchergebnisse

Trabajo presentado en el XII Conference of the Iberian Association for Comparative Endocrinology (AIEC), celebrado en Faro (Portugal), del 26 al 28 de septiembre de 2019. ; Cortisol is the most important hormone involved in the regulation of neuroendocrine stress response in teleosts. Effects of this hormone are mediated through its intracellular receptors, although membrane components are also involved, with unclear roles during the stress response. In this work, the contribution of membrane-initiated cortisol actions on stress-related parameters and metabolism-related genes in gilthead sea bream (Sparus aurata) were evaluated. Two in vivo experiments were performed. In the first, fish were administered with vehicle, BSA, cortisol and cortisol-BSA (membrane impermeable analogue) dissolved in saline (PBS 1X). In the second, the same treatments were replicated but using coconut oil as a vehicle. Fish were sampled after one and six hours (first experiment) and after three days (second experiment). Plasma cortisol, glucose and lactate levels were measured, and hepatic transcript levels of key genes involved in glucose metabolism, like glucose-6-phosphatase (g6pc), phosphoglycerate mutase 1 (pgam1), among others, were also analyzed. Fish implanted with each version of cortisol in both in vivo experiments reached plasma levels typically observed under an acute stress in S. aurata. Cortisol and cortisol-BSA increased glucose and lactate plasma levels after six hours of treatment. However, cortisol, but not cortisol-BSA, maintained increased plasma glucose levels after three days of treatment. Analysis by qPCR showed that expression of g6pc increased after one hour of cortisol and cortisol-BSA administration. However, cortisol, but not cortisol-BSA, maintained the g6pc up-regulation after three days. Our results suggested that membrane-initiated cortisol actions contributed to the regulation of early metabolic adaptations in S. aurata submitted to an emulated acute stress situation. ; This work was funded by Spanish Ministry of Science, Innovation and Universities - MICINN (AGL2016-76069-C2-1-R) awarded to JMM. The authors belong to the Fish Welfare and Stress Network (AGL2016-81808-REDT), supported by the Agencia Estatal de Investigación (MICINN, Spanish Government). ; Peer reviewed

15 pages, 6 figures, supplementary material https://doi.org/10.1007/s10126-019-09886-x ; The European sea bass is one of the most important cultured fish in Europe and has a marked sexual growth dimorphism in favor of females. It is a gonochoristic species with polygenic sex determination, where a combination between still undifferentiated genetic factors and environmental temperature determines sex ratios. The molecular mechanisms responsible for gonadal sex differentiation are still unknown. Here, we sampled fish during the gonadal developmental period (110 to 350 days post fertilization, dpf), and performed a comprehensive transcriptomic study by using a species-specific microarray. This analysis uncovered sex-specific gonadal transcriptomic profiles at each stage of development, identifying larger number of differentially expressed genes in ovaries when compared to testis. The expression patterns of 54 reproduction-related genes were analyzed. We found that hsd17β10 is a reliable marker of early ovarian differentiation. Further, three genes, pdgfb, snx1, and nfy, not previously related to fish sex differentiation, were tightly associated with testis development in the sea bass. Regarding signaling pathways, lysine degradation, bladder cancer, and NOD-like receptor signaling were enriched for ovarian development while eight pathways including basal transcription factors and steroid biosynthesis were enriched for testis development. Analysis of the transcription factor abundance showed an earlier increase in females than in males. Our results show that, although many players in the sex differentiation pathways are conserved among species, there are peculiarities in gene expression worth exploring. The genes identified in this study illustrate the diversity of players involved in fish sex differentiation and can become potential biomarkers for the management of sex ratios in the European sea bass and perhaps other cultured species ; This work was supported by Spanish Government Consolider-Ingenio 2010 grant "Aquagenomics" (ref. CDS2007-0002) to SMK, FM, SZ and FP. BC was supported by an Aquagenomics contract; LR was supported by Aquagenomics postdoctoral contract; ND was supported by Aquagenomics predoctoral contract. NSB was supported by AGL2016-78710-R ; Peer Reviewed