Safety of goods and civilians towards the terrorist risk constitutes a research orientation of public interest, confirmed by the 2013 edition of the “Livre blanc de la Défense et de la Sécurité Nationale”. In particular, the risk of Nuclear or Radiological attack remains one probable and serious risk, following the emergence of nations sufficiently developed and favorable to develop this kind of armament. In this context, it is important to have passive detection of ionizing rays. In our case, we take interest in the detection of neutrons, immutable signature of the presence of materials allowing the preparation of nuclear weapons. In addition to the societal aspect, the economic aspect is crucial because such detectors, containing 3He gas, currently exist, but their lack prevents their deployment on large surfaces. We thus wish to develop polymeric materials allowing the detection of these neutrons at lower costs, as well as a prototype containing these sensors.

The NADPH-oxidase is essential for the innate immune defence and is present in professional phagocyte cells. The activation of this complex is tightly regulated and involves phosphorylation events correlated to specific protein-protein interactions and chemical modifications. The phagocyte NADPH-oxidase has become the prototype of a family of electron transport system (NADPH-oxidase family) recently discovered in various tissues. They all share the capacity to produce superoxide radical from the reduction of molecular oxygen. The active enzyme is the result of the translocation of four cytosolic proteins to the membrane component, the so-called Flavocytochrome b558 (Cytb558). The Cytb558 is the catalytic core of the NADPH-oxidase that generates superoxide anion from oxygen by using reducing equivalent provided by NADPH via FAD and two hemes. A dysfunction of NADPH-oxidase leads to severe immune disease and to other important human pathologies. Our aim is to understand the functioning of this dynamic membrane-bound electron-transferring enzyme by studying its functional and structural properties in a cell-free system (in vitro). Several important steps in the NADPH-oxidase functioning have been identified. However, at the molecular level, many questions remain. The limiting factor for functional and structural studies is the lack of sufficient amounts of the membrane flavoprotein in stable, pure and homogeneous form. We recently overcame this bottleneck by producing the recombinant Cytb558 in a yeast expression system. Associated with the recombinant cytosolic proteins, the Cytb558 forms a totally recombinant cell-free system, free of cell signaling constraints and in which the environment can be easily controlled. Our aim is to take advantage of this new tool to elucidate, at the molecular level, the mechanisms underlying the reactive oxygen species production (involving protein-protein interaction, fatty acid activation, electron transfer reaction,…). Using a wide range of expertises (molecular biology, biochemistry, fluorescence and absorption spectroscopy, radiation biology and structural biology), we will gain new insight into the key structural and functional features of the protein components that control the activation and inhibition of the enzyme assembly processes and the coordination of the different redox partners. The methods like the stopped flow technique and pulsed radiolysis that we intend to use, have, to our knowledge, never been applied to analyze the NADPH-oxidase functioning. These are methods of choice to determine the reaction intermediates leading to the superoxide generation within the Cytb558 and to decipher the mechanism underlying the activation processes of the catalytic subunit. They are likely to yield unprecedented insight into the NADPH-oxidase biological functions. A fundamental aspect in this project is that the large scale production of the catalytic Cytb558 will enable us to make progress towards the determination of the three-dimensional structure of this membrane protein. This challenging project will combine a comprehensive set of biophysical, biochemical and structural approaches for the study of the NADPH-oxidase. These approaches will provide a better understanding of the molecular mechanisms underlying in the cellular process and will facilitate attempts at rational drug design where membrane proteins are often key target molecules.

Cometary dust particles rain on Earth. However, they can only be found in collections performed in the cleanest regions of the Earth (the stratosphere and Antarctica). From Antarctic snow at the vicinity of the French-Italian Concordia Antarctic base, we recovered large (> 50-100 µm) particles of very probable cometary origin, the Ultracarbonaceous Antarctic Micrometeorites (UCAMMs). UCAMMs are constituted of a dominant fraction of a solid macromolecular organic matter intimately mixed with a minor mineral component. The organic matter is structurally disorganized, shows large deuterium enrichments and exhibit an unusually large bulk nitrogen concentrations (up to 20 at%). Preliminary studies have shown that several types of organic matter co-exist in UCAMMs, with different nitrogen contents and mixed with different amounts of minerals. The minerals embedded in the organic matter have typical sizes around 50-100 nm. Both crystalline and amorphous minerals are present and exhibit a wide range of compositions. Some precursors of UCAMM organic matter (the most N-rich) could have been formed by galactic cosmic rays’ irradiation of nitrogen-rich ices at the surface of icy bodies in the outer regions of the protoplanetary disk. UCAMMs are remarkable particles as their subcomponents preserved records of early solar system formation and evolution. The association in UCAMMs of minerals (formed at high temperatures) among large amounts of organic matter (necessarily formed at lower temperatures) opens a new window on the study of the origin and formation mechanisms of matter originating from the outer regions of the solar system. This proposal focuses on the formation mechanism and evolution of cometary dust organics and their relation with the mineral components embedded within, following 3 main questions: 1. What is the origin of the subcomponents of cometary matter? "Inner and outer solar system…" 2. What are the variations of the composition of organics and their embedded minerals with heliocentric distance? 3. How did the different environments encountered (radiative interplanetary medium, terrestrial atmosphere, Antarctica) modify the cometary particles collected on Earth? This project proposes innovative analysis protocols of UCAMMs using state-of the-art analysis techniques to characterize both the organic matter, the minerals and their association. Experimental simulations of their evolution from interplanetary space to their collection in Antarctica will be performed on cometary organic analogues and on synthetic UCAMMs produced in the laboratory. The originality of the COMETOR proposal resides in four points: i) the availability in the laboratory of well-preserved cometary samples; ii) the analysis of these complex particles with a combination of complementary and state-of-the-art techniques – including infrared spectroscopy coupled with atomic force microscopy (AFMIR) that allows infrared analysis at the ~ 50-100 nm scale; iii) the production of analogues of cometary solids and the real-time observation of their evolution under irradiation thanks to the unique JANNuS platform, coupling a transmission electron microscope with two ion accelerators; iv) the search for soluble organic compounds (including amino acids) in UCAMMs with the very high mass resolution Orbitrap technique to probe the input of prebiotic molecules on the early Earth by cometary dust. The expected results will have implications in the fields of astrophysics, planetology-cosmochemistry and astrobiology. They will bring an original contribution to the understanding of the formation and evolution of solid matter in the outer regions of the protoplanetary disk, as well as important inputs for the interpretation of data from Rosetta and Stardust samples, from samples returned by future space missions such as Hayabusa 2, OSIRIS-Rex, and for the observations of protoplanetary disks by the future James Webb Space Telescope (JWST).

The objectives of this project are twofold and range from fundamental understanding of the separation process of isomers using differential mobility spectrometry (DMS) hyphenated to tandem mass spectrometry (MS/MS) to developing robust methodologies for isomer identification and quantification for targeted metabolomics analyses. Our ambition is thus to bridge gap between development of gas phase physical chemists (partner 1) and clinical biology (partner 2). Our idea is to couple three orthogonal techniques: DMS, MS/MS, and an isomer-selective ion fragmentation based on infrared absorption, which could be considered as a « selective multiple reaction monitoring » (IR-MRM) method. Proof of principle of the application of our DMS-MS/MS(IR) approach for the identification of metabolite isomers has been published in 2018. Current standard protocols based on the coupling of liquid chromatography to tandem mass-spectrometry (LC-MS/MS) have some drawbacks which could be overcome with DMS-MS/MS(IR): large volume of (toxic) solvents to be recycled, and the fact that only a set of molecules with comparable polarities can be isocratically separated. In adding, separation of relevant metabolites from isobaric and/or isomeric compounds is often difficult. Through systematic studies of sets of targeted metabolites, relevant for different MDs, we want to challenge the robustness of DMS. Our analytical targets are biomarkers of metabolic diseases (MDs), which are life-threatening inherited metabolic defects that irremediably lead to significant organ dysfunctions (i.e. brain, liver, cardiac, kidney, muscle...). Two applications dedicated to MD diagnosis will be performed in order to address the topics of emergency in metabolic diagnosis and newborn screening from blood samples.

This proposal aims at investigating both theoretically and experimentally the laser-control at the quantum level of relatively large molecular systems in a consortium gathering relevant expertise in quantum chemistry, quantum dynamics and quantum control. We will focus on photochemical mechanisms in organic compounds featuring conical intersections, such as the ring-opening reaction for spiropyran molecules. A model for the diabatic potential energy surfaces of the benzopyran molecule including all 48 degrees of freedom will be developed, and the recent Multi-layer Multi-Configuration Time-Dependent approach (ML-MCTDH) will be used to simulate the quantum dynamics of the system in presence of laser pulses. Effective systems through active (coupled) molecular and field coordinates will be derived. Systematic strategies to control the photoreactivity of the system will be developed theoretically (using an approach of molecules “dressed” by the external fields) and implemented experimentally. Combinations and improvements of scenarios based on (but not limited to) resonant Pump-dump control, Stark effect, feedback optimization, optimal control and preliminary vibrational excitation will be investigated through direct cooperation between the theoreticians and the experimentalists of the consortium.