Search results

Abstract Primarily described as an alarmone, secondary messenger (p)ppGpp, when accumulated, binds to many targets involved in DNA replication, translation, and transcription. In the asymmetrically-dividing a-proteobacterium Caulobacter crescentus, (p)ppGpp has been shown to strongly impact cell cycle progression and differentiation, promoting the non-replicating G1/swarmer phase. Mutations in the major subunits of transcriptional complex, b or b' subunits, were able to display the (p)ppGpp-related phenotypes even in the absence of the alarmone. We identified that the transcriptional holo-enzyme, RNA polymerase (RNAP) is a primary target of (p)ppGpp in C. crescentus. Furthermore, mutations that inactivate (p)ppGpp binding to RNAP annihilated the (p)ppGpp-related phenotypes and phenocopied a (p)ppGpp0 strain. Our RNAseq analysis further elucidated the changes in the transcriptional landscape of C. crescentus cells displaying different (p)ppGpp levels and expressing RNAP mutants. Since the DNA replication initiation protein DnaA is required to exit the G1 phase, we observed that it was significantly less abundant in cells accumulating (p)ppGpp. We further explored its proteolysis under the influence of (p)ppGpp. Our work suggests that (p)ppGpp regulates cell cycle and differentiation in C. crescentus by reprogramming transcription and triggering proteolytic degradation of key cell cycle regulators by yet unknown mechanisms. In Part II, we identified two σ factors belonging to the ECF family that might be involved in this (p)ppGpp-accompanied phenotypes. In Part III, we propose an overlapping role of the ω subunit, RpoZ, and the heat shock subunit, RpoH, in carbon metabolism.JuryProf. Gipsi LIMA MENDEZ (UNamur), PresidentProf Régis HALLEZ (UNamur), SecretaryDr Emanuele BIONDI (CNRS-Université Paris-Saclay)Prof. Justine COLLIER (University of Lausanne)Dr Marie DELABY (Université de Montréal)

Abstract Estrogens originating from human and animal excretion, as well as from anthropogenic sources such as cosmetics, plastics, pesticides, detergents, and pharmaceuticals, are among the most concerning endocrine-disrupting compounds in aquatic environments due to their potent estrogenic activity. While their effects on fish reproduction are well documented, their impact on development, particularly metamorphosis, remains poorly studied. This hormonal transition, mainly controlled by the thyroid axis, is essential for the shift from the larval to the juvenile stage in teleosts.The effects of two contraceptive estrogens on zebrafish (Danio rerio) metamorphosis were evaluated: 17α-ethinylestradiol (EE2), a synthetic reference estrogen, and estetrol (E4), a natural estrogen recently introduced in a new combined oral contraceptive formulation. Continuous exposure from fertilization to the end of metamorphosis allowed the assessment of morphological changes, disruptions of the thyroid axis, and modifications of additional molecular pathways potentially involved in metamorphic regulation.EE2 induced significant delays and disturbances in metamorphosis, affecting both internal and external morphological traits, confirming its role as an endocrine disruptor of concern. In contrast, E4 did not cause any detectable morphological alterations even at concentrations far exceeding those expected in the environment, indicating a limited ecotoxicological risk. Molecular analyses showed that EE2 strongly affected thyroid signaling and energy metabolism during metamorphosis, whereas E4 induced only minor transcriptional and proteomic changes.This study provides the first evidence that EE2 can disrupt zebrafish metamorphosis and highlights the importance of including this developmental stage in ecotoxicological assessments. The results also suggest a larger environmental safety margin for E4, although further research is needed to clarify the mechanisms linking estrogen exposure to metamorphic regulation.JuryProf. Frederik DE LAENDER (UNamur), PresidentProf. Patrick KESTEMONT (UNamur), SecretaryDr. Sébastien BAEKELANDT (UNamur)Dr. Valérie CORNET (UNamur)Prof. Jean-Baptiste FINI (Muséum National d'Histoire Naturelle, Paris)Dr. Marc MULLER (ULiège)Prof. Veerle DARRAS (KULeuven)

Program 5-6pm: Student read-aloud6-7:30pm: Lecture by Julia Kerninon7:30pm-9pm: DrinkConference and performance aimed at students but open to all, interns and externs. Free but reservation required (aurelie.sinte@unamur.be)

The two authors will each read an excerpt from their book, then explain their choice to explore the themes of foot travel, nature and memory in their works. This reading will be followed by a discussion during which the audience and our students will be able to ask questions.This event aims to establish links between our research in "embodied cognition", cognitive narratology and travel literature, and our teaching activity. It will enable us to offer our students a bilingual activity while promoting the teaching and study of literature at UNamur and within the NaLTT Institute. We hope to invite interested researchers and their students via our respective networks. With this theme, we will also fit in with UNamur's ecological and pedagogical objectives.

Angélique Aristondo, a C2W post-doctoral fellow at UNamur, has distinguished herself by winning the second 2023 Gender and Health Research Award from the ARES Women and Science Committee. Her research project focuses on violence against women in Senegal.

On January 23 and 24, 2025, UNamur experts were present at the SETT (School Education Transformation Technology) trade show for its sixth edition. A must-attend event for digital education in the Wallonia-Brussels Federation, dedicated to principals, teachers and technical-pedagogical advisors.

Two researchers at the Institut du Langage, du Texte et de la Transmédialité (NaLTT) have just been awarded funding from the F.R.S - FNRS following calls whose results were published in December 2024.Composed of researchers in linguistics and literature, the NaLTT Institute constitutes an interdisciplinary space for diachronic and synchronic research into verbal and multimodal communicative practices that manifest themselves in, are shaped and/or regulated by culture and society.

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.

On 15 March 2023, Prof. Henri-François Renard and Prof. Alison Forrester introduced the new advanced bioimaging tools of the UNamur Morphology & Imaging technology platform available to a broad audience of users.