LE STUDIUM Multidisciplinary Journal

Peatlands are key ecosystems in the global carbon balance due in part to the slow microbial degradation of the organic matter (OM) in peat soils. Role of peatlands as powerful carbon storage systems may be threatened by climate change, leading to a potential huge release of greenhouse gases to the atmosphere. Our knowledge on the mechanisms behind the microbial OM degradation is still incomplete, and it is also essential to develop better management strategies and mitigate global change impacts. In the frame of the present fellowship, the microbial extracellular enzymatic mechanisms of the OM degradation in peat soil and pore water were studied in a French altered peatland, assessing changes in soil depth and warming effect during an annual cycle. Additionally, to the research programme, during the present fellowship a new technique for the host laboratory was implemented (protocol to measure extracellular enzyme activities in pore water and peat soil), the fellow participated in several conferences and seminars, three publication were or are in the process of being published, and a new project with the host laboratory is in developing.

A protic ionic liquid is inctroduced for the first time as a solvent for a high energy density vanadium redox flow battery.  The proof-of-concept redox flow cell with a concentration of 3 mol L⁻¹ vandyl sulfate electrolyte was tested for a total of 30 cycles at 40°C, showing an open circuit potential of 1.38 V, a nominal capacity of 1900 mAh at a current density of 40 mA cm⁻¹ and energy and coulombic efficiencies of 64 and 90%, respectively. The continuous 16 hours of cycling suggest that the concentrated anolyte and catholyte are thermally stable and cycleable. This study underlines a new route to improve the energy-to-volume ratio of this promising energy storage system.

This Le Studium Fellowship was used to analyze the crystal growth in levitated melts. Furthermore, methodical questions concerning the method EBSD as well as XRD were addressed. Finally, the literature concerning oriented surface nucleation in glasses was completed. 

Inspired by the active site of the copper-zinc superoxide dismutase enzyme, we studied the reactivity of imidazolic ligands to improve the design and synthesis of coordination compounds, active against the superoxide radical (responsible of DNA, cellular and tissues damage, leading to illness like cancer, atherosclerosis, heart failures, etc.). By the joint use of first-principle calculations and solid state NMR spectroscopy, we identified the relationship between the structural characteristics and the reactivity of the synthesized compounds, that lead and modulates their antioxidant activity. 

Infections with parasitic helminths expose serious health threats to humans and animals alike. Prevention of disease is dependent on the effective treatment using anthelmintics. Unfortunately, anthelmintic resistance (AR) has evolved in many helminth species during the past decades and meanwhile poses a major constraint to established worm control approaches. This project aimed to improve our understanding of the molecular mechanisms by which helminths, particularly the potentially deadly horse parasite Parascaris sp., become capable of withstanding drug treatment. To this end, Parascaris P-glycoproteins (Pgp), belonging to an important group of mediators of anthelmintic resistance, were introduced into the model organism Caenorhabditis elegans using the CRISPR/Cas9 technology. The resulting transgenic lines will subsequently be analyzed to functionally elucidate the role of putatively AR-associated Parascaris Pgp sequence polymorphisms.

Evidence exists that the gonadotropins LH and FSH can substitute to each other under certain circumstances, in addition to the fact that they can act together in granulosa cells. The aim of this study is to investigate how the two human gonadotropins influence each other in granulosa cells expressing both receptors, or by co-culturing cells expressing either the LHCGR or the FSHR (as a model granulosa/theca interaction). Plasmids encoding the c-myc-tagged-LHCGR and the FLAG-tagged FSHR under the control of an inducible coumermycin-responsive or doxycycline-responsive promoter, respectively were produced. These plasmids were used to permanently transfect human granulosa cell-derived KGN cells and HEK293 cells. The following cell lines were obtained and partially characterized: #1 c-myc-tagged-LHCGR-KGN; #2 FLAG-tagged FSHR_HEK293; #3 FLAG-tagged FSHR-KGN; #4 Double, c-myc-tagged-LHCGR and FLAG-tagged FSHR-KGN. After induction of receptor expression, the cell lines #1 and #2 and #3 responded to hCG and FSH stimulation, respectively by producing cAMP. Receptor expression was demonstrated by RT-PCR and flow cytometry. The characterization of the cell line #4 is ongoing. These cell lines are now available for the study of cell signaling and steroid synthesis, as well as in silico modeling, to gain insight into the dynamics of the intertwined cell response to FSH and LH in granulosa cells. These experiments will continue in parallel in both laboratories involved. Our cell lines represent new, very valuable instruments for the study of molecular pharmacology of FSH and LH, in order to improve infertility treatment, (multi)follicular growth for assisted reproduction, ovulation and spermatogenesis.

Building upon recent developments in digital music scholarship, Citations: The Renaissance Imitation Mass investigates similarity and borrowing in music on a massive but detailed scale, using digital tools that only a few years ago were beyond our grasp. Our work focuses on the craft of musical counterpoint, and how musicians of the sixteenth century transformed pre-existing pieces to make intricate cyclic compositions from familiar sounds. The CRIM team, an accomplished group of scholars and data scientists active in Europe, North America, and Australia, will assemble a diverse collaborative network of music scholars and students at colleges, music schools and university graduate programs, extending the reach of digital scholarship to new users, and building new communities.

Herbal plants accumulate large amounts of phenolics and pentacyclic triterpenes. The present research project deals with the in vitro culture induction from stem and leaf explants of several medicinal plant species of Centre-Val de Loire under various plant growth regulators (PGRs) for the production of antioxidant and anti-ageing compounds. Among all the tested PGRs, auxins and cytokinins used alone or in combination induced callogenesis in stem/leaf-derived explants. Callus culture displayed feasible total phenolic content and antioxidant activity under optimum hormonal combination. HPLC analysis revealed the presence of plectranthoic acid, oleanolic acid, betulinic acid, caffeic acid and rosmarinic acid. Complete antioxidant and anti-aging potential of extracts with very contrasting phytochemical profiles were investigated. Correlation analyses revealed rosmarinic acid as the main contributor for antioxidant activity and anti-aging hyaluronidase, advance glycation end-products inhibition and SIRT1 activation, whereas, pentacyclic triterpenoids were correlated with elastase, collagenase and tyrosinase inhibition. Altogether, these results clearly evidenced the great valorization potential of herbal plants from CVL for the production of antioxidant and anti-aging bioactive extracts for cosmetic applications.

Although cortical elements of the limbic system are quite well defined, the underlying white matter pathways are not well detailed. This project aimed to better describe white matter tracts of the limbic system using both fiber dissection, and in and ex vivo Diffusion Weighted Imaging (DWI) techniques. In vivo data (from DWI and neuropsychological evaluations) were obtained from healthy subjects aged 82 and over previously enrolled in the FIBRATLAS project funded by the French Research Agency and run in the host laboratory. Correlations between neuropsychological and white matter characteristics on DWI were examined in this group to infer function of the limbic white matter tracts. Ex vivo data from the FIBRATLAS project database and from the Tours Body Donation Program were examined. The brains were extracted and used to study the anatomy of the limbic white matter tracts employing both DWI and fiber dissection according to a variant of the Klingler’s method.

We design a scheme for the Euler equations under gravitational fields based on our subcell hydrostatic reconstruction framework.

To give a proper definition of the nonconservative product terms due to the gravitational potential, we first separate the singularity to be an infinitely thin layer, on where  the potential is smoothed  by defining an intermediate potential without disturbing its monotonicity ; then the physical variables are extended and controlled to be consistent with the Rayleigh-Taylor stability, which contribute the positivity-preserving property to keep the nonnegativity of both gas density and pressure even with vacuum states. By using the hydrostatic equilibrium state variables the well-balanced property is obtained to maintain the steady state even with vacuum fronts.  In addition, we proved the full discrete discrete entropy inequality, which preserve the convergence of the solution to the physical solution, with an error term which tends to zero as the mesh size approaches to zero if the potential is Lipschitz continuous. The new scheme is very natural to understand and easy to implement.

The numerical experiments demonstrate the scheme's robustness to resolve the nonlinear waves and vacuum fronts.