Reference : UMR7360-CATPIE-023
Workplace : VANDOEUVRE LES NANCY
Date of publication : Monday, November 14, 2022
Type of Contract : FTC Scientist
Contract Period : 15 months
Expected date of employment : 1 February 2023
Proportion of work : Full time
Remuneration : between 2690€ and 3099€ gross monthly
Desired level of education : PhD
Experience required : Indifferent
Several PFTs related to the aerolysin toxin have been identified so far from i) Biomphalaria glabrata, an intermediate host snail vector of Schistosomiasis, and from ii) its parasite Schistosoma mansoni. Among them, Biomphalysin 1 was shown to interact with the surface of the parasite leading to its death. The general scope of this project supported by the ANR grant AeroSNAIL led by the IHPE laboratory in Perpignan (http://ihpe.univ-perp.fr/) is to characterize the regulation, the biological activity and the structure of different aerolysin-related toxins in the species Biomphalaria glabrata and Schistosoma mansoni by combining novel functional, structural and nano-biophysical approaches.
For this PostDoctoral position, the candidate will specifically use Atomic Force Microscopy in both imaging and force spectroscopy modes to quantify, at the molecular scale, the specific interactions operating between selected toxins produced by Biomphalaria glabrata and/or Schistosoma mansoni and their most relevant cellular targets, i.e. synthetic surfaces coated with purified receptors (lipids, polysaccharides, proteins), and living bacteria or blood cells. The candidate will also address the change in the morphology and nanomechanical properties of the targeted cells after their incubation with toxins using nano-indentation Atomic Force Microscopy, possibly complemented by Confocal Microscopy and Holotomography measurements.
The candidate will be located in the Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC, https://liec.univ-lorraine.fr/) in the group 'Physical Chemistry and Reactivity of Surfaces And interfaces'' with renown expertise in Atomic force Spectroscopy and Surface Biophysics. The candidate will have to closely interact with all partners of AeroSNAIL consortium, including the group of L. Maveyraud (University Paul Sabatier, Toulouse) in charge of the production of the recombinant toxins and their crystallization, and the group of B. Gourbal (IHPE, University Perpignan) involved in the analysis of toxin biological functions.
• Monitoring the morphological and nanomechanical properties of targeted cells after incubation with selected recombinant toxins within concentration ranges specified by Perpignan partner.
• Visualization by AFM of prepore and pore formed by oligomerization of toxin monomers on solid substrates, synthetic lipid bilayers and targeted cell surfaces.
• Nanoscale AFM-based single-molecule force spectroscopy measurements of the specific adhesion events using AFM tips functionalized with recombinant toxins.
• Imaging of prepore and pore formation at the surface of Schistosoma parasite as a result of recombinant or endogenous toxins from snail plasma.
• Have a solid experience in AFM (imaging and force spectroscopy measurements applied to biological samples in liquid conditions)
• Knowledge in biochemistry, microbiology, cell culture, and/or supported bilayer formation would be an added value,
• Be results-driven, have a marked sense of autonomy while being eager to work in a dynamic team,
• Able to manage deadlines,
• Have good communication skills (both oral and written) in English (knowledge in French is not required).
A diverse array of toxin and antitoxin systems widely distributed among organisms has emerged between pathogens and their hosts as strategies for defense or virulence [1,2]. These toxins can be found in different organisms, from bacteria to metazoans, and they exhibit highly specific actions over a broad range of cellular pathways, thereby triggering a large spectrum of physiological effects such as neurotoxicity or necrosis [3-5]. Selection pressures operating in host-pathogen interactions have generated a repertoire of specific toxins harboring distinct selectivity towards targeted cell types, thus providing promising tools for applications as therapeutic agents in molecular pharmacology [6-8]. Among the most common toxins present in all kingdoms of life, Pore-Forming Toxins (PFT) are a large class of biological weapons used by prokaryotes as virulence factors and by eukaryotes in immune responses. Overall, these toxins are secreted as soluble protoxins and undergo a conformational change to form oligomeric pores in membrane subsequent to their interactions with specific receptors located at the membrane surface of the targeted cells [1,9,10]. In some cases, proteolytic cleavage is required to form the active toxin . Many studies have highlighted the extensive range of receptors recognized by PFTs, which includes lipids, sugars or membrane proteins [12-14].
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