Description du sujet de thèse

How did life emerged on Earth? This is one of the most fascinating questions of science. Until now, interest has focused mainly on the formation of the first molecules essential to life, such as amino acids, lipids and sugars, without considering the source of energy that would have enabled such molecules to appear.
In living beings, this energy is provided by ATP (Adenosine TriPhosphate) or, more precisely, by an ADP/ATP disequilibrium, produced by a process known as chemosmosis. This mechanism uses charge number disequilibrium between the inside and outside of cells, produced by redox reactions, to produce energy. One hypothesis is that this process, present in all living organisms, played a key role in the emergence of life.
The PrimLife project aims to test this hypothesis. To do so, we will recreate in laboratory conditions close to those of submarine hydrothermal alkaline vents, where minerals could both produce energy through a mechanism similar to chemosmosis and promote the formation of the first molecules of life.
This project could thus demonstrate that minerals in these extreme environments played a fundamental role in the emergence of life on Earth.

Contexte de travail

This PhD will be co-supervised by Simon Duval from the "Evolution of Bioenergetics" team at the BIP laboratory (PhD supervisor) for the redox and bioenergetic aspects of mineral membranes, and in collaboration with Grégoire Danger from the PIIM laboratory for the analysis of organic molecule formation and Daniel Ferry from the CINaM for mineral characterization.
The host lab, BIP, is interested in origin of life using top down approach for BIP by comparing minerals and proteins properties for chemiosmosis. This project will be done in close collaboration with the PIIM for research of organic molecules and CINaM for the mineral characterization.
The BIP (Bioenergetics and Protein Engineering) (INSB) represents the biological cornerstone of this transdisciplinary project. For 27 years, BIP has studied the diversity of bioenergetic systems. The group has extensive expertise in biochemical, biophysical, and electrochemical methods. Over the past 10 years, the group has increasingly focused on research related to the emergence of life, leading to the establishment of a transdisciplinary research project (biology/bioenergetics, nanosciences, mineralogy, and biogeochemistry).

Contraintes et risques

The PhD candidate will have a background in biology or chemistry and will be responsible for carrying out the project at the BIP in collaboration with PIIM and CINaM. They will produce analogues of mineral membranes from hydrothermal sources under early Earth conditions in the BIP laboratory. These membranes will be thoroughly characterized using electron microscopy (TEM, SEM) and spectroscopy (Raman, Infrared) in collaboration with CINAM (Interdisciplinary Center for Nanoscience of Marseille).
The candidate will then test the formation of organic molecules in the presence of oxidants (CO₂) and reductants (CH₄, H₂) found in primitive hydrothermal sources, using chromatography (GC-MS, LC-MS) in the PIIM laboratory and NMR (IMM platform). A detailed study of the organic molecules formed within the membranes will be conducted using X-ray absorption spectroscopy at the carbon K-edge (STXM-XANES) at the SOLEIL synchrotron (HERMES beamline). Characterization of the different mineral phases will also require Mössbauer spectroscopy in collaboration with LCPM in Nancy.
The PhD candidate will therefore be expected to carry out tasks in Paris and Nancy during the course of the thesis. They will serve as a link between the biology/mineralogy work at BIP and the chemical analysis at PIIM. This project requires a strong interest in interdisciplinary research and the emergence of life. Skills and knowledge in bioenergetics, chemistry, and physical analysis will be essential for the success of this project.