Genes that are activated to changes in water salinity in the gilthead sea bream.

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Genes that are activated to changes in water salinity in the gilthead sea bream.
weee By Administrador Intranet Icman In News Posted 24 June, 2016 0 Comments

Researchers at the Andalusian Institute of Marine Sciences (ICMAN) in Puerto Real, Cadiz, and the Institute of Aquaculture Torre de la Sal (IATS) in Castellon, belonging to the Spanish Council for Scientific Research (CSIC), in collaboration with the University of Cadiz, have identified the genes that are activated to changes in water salinity in the gilthead sea bream.

In the salt marshes of the Bay of Cadiz, ancient marine salt pans used for growing sea bream, salinity varies depending on evaporation (during summer) or the supply of fresh water from rivers or rain. To withstand these variations in salinity, seabream uses a physiological process known as osmoregulation, which aims to get a constant balance of salts within certain ranges between the external environment and the body fluids of fish. This is achieved by the exchange of water and minerals from the fish to the outside and vice versa, which implies the use of energy. Adjusting seabream to changes in salinity creates a stressful situation that involves an energetic effort. On the other hand, when fish are in a milieu in which a salt balance is reached between the internal and external environments, the osmoregulatory effort is not necessary and this energy is not consumed, which can be dedicated to other physiological processes such as growth.

Under these osmotic stress situations, the behavior of more than 15,000 genes of seabream in three different tissues, gills, liver and hypothalamus, involved respectively in acclimation to salinity conditions, the extra energy demand and the control of all physiological processes involved, were studied. A methodology called ‘microarray’ was used to analyze, in a single tissue sample, thousands of genes all together. This type of studies has been focused on a single organ until now. They had never been used in a comparative analysis of different organs dealing with different physiological functions. In this way, it has been possible to analyze the transcriptome of three tissues, i.e., to define the set of genes expressed and responding within the cells of these three organs in a given moment. This study increases the possibilities for further research into genetic selection of fish lines which may have a greater potential to adapt to environments of high or low salinity, representing a clear application for aquaculture of this important species.

These investigations have been made under the project AQUAGENOMICS (CDS2007-00002) of the Ministry of Economy and Competitiveness co-financed by ERDF.

Juan Antonio Martos-Sitcha, Juan Miguel Mancera, Josep Alvar Calduch-Giner, Manuel Yúfera, Gonzalo Martínez-Rodríguez, Jaume Pérez-Sánchez. ‘‘Unraveling the tissue-specific gene signatures of gilthead sea bream (Sparus aurata L.) after hyper- and hypo-osmotic challenges’’. Plos one. 2016; 11(2): e0148113. http://dx.doi.org/10.1371/journal.pone.0148113