PhD position to study the Rainbow trout amino acid metabolism
UMR1419 INRA-UPPA NuMeA, Saint Pée-sur-Nivelle, France
Application deadline: 01st of April 2018
Starting date: September 2018
Funding: E2S junior chair project from the university of “Pau et des Pays de l’Adour” UPPA
Duration: 3 years
Gross salary: 23 k€ / year
Scientific background: Fisheries and aquaculture remain important sources of food, nutrition, income and livelihoods for hundreds of millions of people around the world. World per capita fish supply reached a new record high of 20 kg in 2014, thanks to vigorous growth in aquaculture, which now provides half of all fish for human consumption (FAO, 2016). Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. However, the sustainability of this practice, which requires large inputs of wild fish for feed, has been questioned (1). Thus, the replacement of fishmeal and fish oil by proteins and oil of alternative origin is a major objective for sustainable aquaculture, and needs improving scientific knowledge in order to optimize fish growth potential while maintaining aquatic products quality and lowering environmental impacts. One of the most striking nutritional characteristics of most fish farmed in Europe is their high protein requirement. Indeed, if most mammals require about 15% of their diet as a protein source to be healthy, in most of aquacultured fish species this value reaches 45% demonstrating their strong and specific dependency on amino acid metabolism. Previous studies in rainbow trout, notably from our laboratory, identified the deleterious outcomes of in-balanced amino acid diets on growth and health (2-9) but the molecular mechanisms involved in these effects still need to be clarified.
Project: In this context, we propose to study amino acid metabolism in rainbow trout, from specific amino acid transporter activities to signalling pathways governed by amino acids. Despite that amino acids were previously shown to activate the mechanistic Target Of Rapamycin Complex 1 (mTORC1) in trout – a protein complex responsible for cell growth and proliferation – nothing is known about the mechanisms by which amino acids are up-taken in trout. Aware that amino acid transporters are crucial players in mammals for mTORC1 activation, we aim to identify amino acid transporters in trout and study their specificities as well as the outcomes of their different expression levels on trout metabolism and physiology. This project represents a great opportunity for a PhD student to acquire a full range of skills and knowledges to perform an integrative study (from gene to animal) using in vitro and in vivo approaches. Using fish cell lines, the PhD student will learn basic and innovative molecular and cellular technics useful to understand trout’s amino acid metabolism and signalling. Furthermore, the PhD student will have the chance to challenge his/her hypothesis built from in vitro results by performing in vivo experiments for which best candidate genes will be deleted from whole organism to evaluate outcomes on the physiology, growth and health of trout. Altogether this study will considerably help to better understand amino acid metabolism in trout and will offer new strategies to develop appropriate diets for trout aquaculture. The successful candidate will work in a young and dynamic group in close collaborations with local, national and international talented scientists. He/she will also be given the opportunity to be involved in the teaching program of the University of Pau for a total of 32 hours per years.
Key words: mTOR, amino acid metabolism, autophagy, growth factor, fish, aquaculture
Applicant‘s profile: The ideal candidate has a master degree in biochemistry or cellular biology. He/She is passionate for biology, rigorous and highly motivated. A previous experience in molecular and cell biology techniques would be a plus. The candidate must have a good English level and the capacity to work autonomously.
Application will include (in a single pdf file):
– A curriculum vitae – A motivation letter
– 2 reference letters
Application must be send to the following email address with the title “Phd application”: PhD.Postdoc.E2S.NuMeA@gmail.com.
For more details, please visit our website (https://www6.bordeaux-aquitaine.inra.fr/st_pee_eng/UR-NuMeA) or feel free to contact us using the same email address with the title “Informations”.
1. R. L. Naylor et al., Feeding aquaculture in an era of finite resources. Proc Natl Acad Sci U S A 106, 15103 (2009).
2. S. Metayer-Coustard et al., Methionine deprivation regulates the S6K1 pathway and protein synthesis in avian QM7 myoblasts without activating the GCN2/eIF2 alpha cascade. J Nutr 140, 1539 (2010).
3. M. Lansard, S. Panserat, E. Plagnes-Juan, I. Seiliez, S. Skiba-Cassy, Integration of insulin and amino acid signals that regulate hepatic metabolism-related gene expression in rainbow trout: role of TOR. Amino Acids 39, 801 (2010).
4. M. Lansard et al., L-leucine, L-methionine, and L-lysine are involved in the regulation of intermediary metabolism-related gene expression in rainbow trout hepatocytes. J Nutr 141, 75 (2011).
5. I. Seiliez et al., Amino acids downregulate the expression of several autophagy-related genes in rainbow trout myoblasts. Autophagy 8, 364 (2012).
6. J. Averous, J. C. Gabillard, I. Seiliez, D. Dardevet, Leucine limitation regulates myf5 and myoD expression and inhibits myoblast differentiation. Exp Cell Res 318, 217 (2012).
7. I. Belghit et al., Dietary methionine availability affects the main factors involved in muscle protein turnover in rainbow trout (Oncorhynchus mykiss). Br J Nutr 112, 493 (2014).
8. W. Dai, S. Panserat, E. Plagnes-Juan, I. Seiliez, S. Skiba-Cassy, Amino Acids Attenuate Insulin Action on Gluconeogenesis and Promote Fatty Acid Biosynthesis via mTORC1 Signaling Pathway in trout Hepatocytes. Cell Physiol Biochem 36, 1084 (2015).
9. W. Dai et al., Hepatic fatty acid biosynthesis is more responsive to protein than carbohydrate in rainbow trout during acute stimulations. Am J Physiol Regul Integr Comp Physiol 310, 21 (2016).Tweet