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Characterization of trehalase from Acyrthosiphon pisum for the design of new insecticides SummaryAphids are major pests in agriculture, causing direct damage to plants and acting as vectors for phytopathogenic viruses. Conventional insecticides are widely used to control them, but their toxicity and efficacy pose problems in terms of the environment, human health and the emergence of resistance to these compounds. New alternatives are therefore needed, such as biological control using predators or parasitoids. However, these methods are not always economically viable on a large scale. As part of this thesis, another approach is being explored which involves developing new insecticides targeting the biochemical functions of aphids.The project aims to discover new inhibitors of trehalase, an enzyme essential for insect energy metabolism. Inhibition of this enzyme could disrupt vital insect functions without affecting mammals. This research involved several stages: the purification and complete characterization of trehalase from Acyrthosiphon pisum (the model for this study), the in vivo, in vitro and in silico analysis of commercial inhibitors on this enzyme, before moving on to the search for new inhibitors. Two points of integrated insect management were explored, biological and chemical control.The biological side saw the study of a strain of Streptomyces naturally producing trehalase-inhibiting metabolites, notably validamycin A, a molecule recognized in the literature as one of the best inhibitors, but not applicable as an insecticide. Other molecules appear to have interesting features, but we have not been able to isolate and characterize them.The chemical side has enabled us to create a pharmacophore hypothesis based on experimental results on molecules obtained by virtual screening. Although these molecules are not usable as insecticides as they stand, this hypothesis provides a better understanding of trehalase inhibitors in general and can be used to refine future analyses. JuryProf. Jean-Yves MATROULE (UNamur), presidentDr Catherine MICHAUX (UNamur), promoter and secretaryProf. Frédéric FRANCIS (ULiège), co-promoterProf. André MATAGNE (ULiège)Dr Rudy CAPARROS (ULiège)Dr Morgan HANS (Biocidal)

High-Sensitivity Birefringence Mapping Using Near-Circularly Polarized Light I will describe several techniques for mapping a two-dimensional birefringence distribution, which can be classified according to the optical schemes and principles of work:Illumination geometry (transmitted light/reflected light)Image acquisition (sequential acquisition/simultaneous acquisition)Polarization control (electrically controlled variable retardance/mechanical rotation).This classification facilitates a comparative analysis of the capabilities and limitations in these methods for birefringence characterization. Polychromatic polarizing microscopy (PPM) provides unique capabilities to alternative methods. It leverages vector interference to generate vivid, full-spectrum colors at extremely low retardances, down to < 10 nm. PPM is a significant departure from conventional polarizing microscopes that rely on Newton interference, which requires retardances above 400 nm for color formation. Furthermore, PPM's color output directly reflects the orientation of the birefringent material, a feature absent in conventional microscopy where color is solely determined by retardance.Joint seminar of ILEE & NISM!The seminar is open to external people too, no need to register. More info

Space has become a major economic and strategic issue. As a member of the European UNIVERSEH Alliance, UNamur explores this space theme in its various departments, from physics to geology, via mathematics, computer science or philosophy. Without forgetting to address the general public, who still dream of the stars...

A delegation from the Université de Namur took part in an exploratory mission to the Université Cheikh Anta Diop (UCAD) in Dakar, Senegal. The aim: to discover the research carried out in the field, meet UCAD researchers and initiate future collaborations between the two institutions.

From 2020 to 2025, as part of her doctoral thesis in history, researcher Julie Duchêne conducted a ground-breaking investigation blending history and biology to trace the cohabitation between humans and wolves in Wallonia and Luxembourg, from the 18th to the early 20th century. Thanks to an innovative interdisciplinary approach, including DNA analysis of naturalized 19th-century specimens, her work sheds light on the mechanisms that led to the local extinction of the species. This research was made possible thanks to the support of numerous scientific and cultural partners.