PRR Project

Summary

This research position involves the study of the morphology, physiology and disruption of the reproductive system and liver-gonad axis interactions of fish, using brown trout as the primary model, while developing and refining cutting-edge tools for replacing in vivo by in vitro assays.First, it aims to establish a portfolio of minimally invasive biomarkers to easily monitor and predict the reproductive stage of adult brown trout throughout the reproductive cycle. A wide set of plasmatic analyses (hematologic, biochemical, fatty acid and hormonal quantifications) and the microRNA profiling using high-throughput sequencing will be implemented. The sampling procedures will include distinct gonadal maturation stages to represent the major phases of the cycle (developing, spawning capable, regressing, and regenerating stages). The investigation of potential biomarkers that best characterise liver/gonad changes throughout the reproductive cycle can then be used for monitoring the physical condition and reproductive capacity of adult brown trout, and thus offers a practical utility for selecting healthy reproducers in aquacultures, avoiding potential reproductive health problems, and maximising fecundity and fertility. Further, the new biomarkers can also be relevant for detecting wild reproduction because they allow individuals to be taken and released in a minimally invasive manner. The concept is extendable to other salmonids, such as the rainbow trout. Brown and rainbow trout are produced in Portugal and exist in the wild, including the brown “sea trout”.In addition, brown trout three-dimensional (3D) cultures (gonad, liver and/or pituitary) should be established and validated to help decipher reproductive pathways and to test potential disruption effects caused by endocrine disruptors and lipid modelling compounds, under temperature-modulated scenarios. In vitro testing is accomplishable with the 3Rs policy, and 3D cultures are systems that have been improved to better resemble in vivo models. Integrative and differential 3D culture models will be established from primary cultures of selected donor fish by categorising by sex and season. The validation of new in vitro fish models is necessary so that new methodologies can integrate fish regulatory guidelines.The dual approach of this research is aligned with the host institution´s mission. On one hand it aims to understand the biological dynamics of a fish species with a high economic/commercial and ecological interest and, on the other, seeks to deepen knowledge of the impacts caused by global changes. Also, in line with the mission of the host institution, the project aims to create new tools for supporting aquaculture and research applications.For achieving the proposed objectives, the ideal candidate must have recognised experience in: (1) handling of fish in the context of environmental sampling and experimental assays, namely with trout (with DGAV accreditation corresponding to FELASA category C, researcher-coordinator); (2) in vivo and in vitro assays; (3) isolation of fish primary cells and their maintenance under 2D and 3D cultures; (4) molecular tools and gene expression analysis; (5) histological processing and immunohistochemical analysis of fish tissues, in particular of liver and gonads; (6) ultrastructural processing and analysis, in particular of liver; (7) enzyme immunoassays; (8) solid basis in toxicology (ADME, exposure and fate of toxicants in organisms); (9) supervision of students in formal internships, dissertations or theses. A know-how in liquid and gas chromatography mass spectrometry (LC/MS and GC/MS) is relevant. The candidate should be highly motivated with strong organisational abilities, outstanding communication skills, in both written and oral contexts, and multidisciplinary collaboration competencies.