Reference : UMR8227-FRATHO-002
Workplace : ROSCOFF
Date of publication : Monday, September 12, 2022
Type of Contract : FTC Scientist
Contract Period : 24 months
Expected date of employment : 1 December 2022
Proportion of work : Full time
Remuneration : 2805,35€ to 3224,81€ monthly gross income depending on experience
Desired level of education : 5-year university degree
Experience required : 1 to 4 years
Marine heterotrophic bacteria play a crucial role in the environment, by recycling macroalgal biomass. The Marine Glycobiology group studies polysaccharides from marine macroalgae and their degradation by environmental bacteria. In particular, we investigate the metabolic pathways and the regulations involved in polysaccharide utilization by marine bacteria. The marine flavobacterium Zobellia galactanivorans is used as a model organism, in which we notably characterized Polysaccharide Utilization Loci (PUL) encoding complete degradation pathways that specifically target alginate (from brown algae) and carrageenans (from red algae). Each of these PUL encodes a transcription factor that controls their expression (AusR and CgrA, respectively). The aim of the postdoctoral project is to explore the yet largely unknown molecular mechanisms of the regulation of these pathways, allowing bacteria to optimize their growth in their natural habitats in the presence of multiple substrates found in algal biomass.
Two hypotheses will be tested:
1) A PUL-encoded regulator can control the expression of distant genes involved in complementary metabolic pathways potentially linked to the degradation of other substrates and/or to the interaction with algae.
2) The presence of non-target substrates can influence the expression of a PUL.
Task 1 will establish the gene network controlled by the regulators AusR and CgrA in the presence of alginate and carrageenans, respectively, using a ChIP-seq approach. Task 2 will allow the experimental validation of the transcriptional control mediated by AusR and CgrA on distant genes identified in Task 1. Finally, task 3 will evaluate the impact of the presence of other algal substrates on the utilization of alginate and carrageenans by cross-regulations.
This postdoctoral contract is part of the X-Reg project funded by the Brittany Region.
The postdoctoral researcher will grow existing wild-type and mutant strains of Zobellia, and create new mutant strains by genetic engineering. He/she will study these strains using ChIP-seq, RT-qPCR approaches and kinetic monitoring of growth profiles in multiple culture conditions. He/she will validate the molecular interactions predicted for the regulators by biochemistry (mobility shift assays). He/she will analyze, interpret and communicate the results.
Applicants must have extensive training in microbiology and molecular biology techniques. Good language and communication skills in English are necessary. Prior experience on transcriptomic analyzes and/or ChIP-seq would be useful.
Applicants should have less than two years of professional experience after their Ph.D, and have spent at least 18 months outside France between May 1st, 2018 and the beginning of the contract.
Work will be performed under the supervision of Dr. François Thomas in the Marine Glycobiology group (Department "Integrative biology of marine models", UMR8227) at the Roscoff Biological Station. The host institute (Roscoff Biological Station) is a research center in marine biology and oceanology located in the Roscoff village on the beautiful North coast of Brittany (France). The project includes a collaboration with INRAE in Jouy-en-Josas in the Paris region, where trips could be necessary.
Constraints and risks
Standard laboratory manipulations in microbiology, molecular biology and biochemistry.
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