In 2021, Professor Frédérik De Laender was approached by American researchers to contribute to a study on the evolution of aquatic diversity in rivers in the USA. The aim: to analyze changes in aquatic diversity and identify the factors behind them. To answer this question, the researchers analyzed data collected over thirty years, covering 389 fish species in nearly 3,000 rivers and streams.

"There was already a lot of data on aquatic diversity in the USA, but it was scattered, recorded in different formats and produced using a variety of techniques and methodologies," explains Frédérik De Laender. "The challenge was therefore to harmonize them, in order to form a coherent whole, capable of revealing trends over several decades and on a continental scale."

In this study entitled "Diverging fish biodiversity trends in cold and warm rivers and streams" researchers studied 389 fish species in 2,992 rivers and streams, between 1993 and 2019. The results show contrasting trends depending on water temperature:

• In cold waters (< 15.4°C), the number of fish fell by 53% and the number of species by 32%. Small fish have declined, replaced by larger species often introduced for sport fishing.
• In warm waters (> 23.8°C), by contrast, the number of individuals has increased by 70% and diversity by 16%, with small opportunistic species dominating.
• Intermediate streams (15-24°C) showed little change.

These trends show that temperature changes and the introduction of certain fish species for fishing are helping to transform local aquatic communities.

Frédérik De Laender is a theoretical community ecologist who studies the links between environmental change, biodiversity and ecosystem functioning. Primarily focused on modeling, he has also conducted experiments on plankton and contributed to meta-analyses. His work focuses in particular on ecological stability and coexistence, to better understand the mechanisms that determine community composition.

The beluga whale (Delphinapterus leucas) of the St. Lawrence Estuary (SLE) in Quebec, Canada, lives in a marine ecosystem heavily impacted by human activities and has shown no signs of recovery for several decades. Also known as the white whale or white dolphin, the beluga has a life expectancy of around 70 years. Infectious diseases and an increase in post-partum mortality in females have been observed, but the exact causes remain undetermined. However, exposure to contaminants is thought to be one of the causes of the increase in early mortality observed in recent years.

One of the main limitations to assessing the health of individuals in this population in relation to contaminant exposure is the lack of a method for determining the age of live beluga whales in the ESL.

Until now, the most reliable method for determining their age was to count the growth streaks on the inside of their teeth. The expertise of Namur-based researchers at Professor Frédéric Silvestre's Laboratoire de Physiologie Évolutive et Adaptative (LEAP) will enable the development of a new "epigenetic clock" and its use to estimate the age of living belugas, ultimately improving conservation strategies to help this threatened population recover.

The project is entitled: "Une horloge épigénétique pour estimer l'âge des belugas du Saint-Laurent et son impact sur l'accumulation de contaminants, le stress et la santé de cette population menacée"

Epigenetics is the study of changes in gene activity, not involving modification of the DNA sequence, that can be transmitted during cell divisions. One of the elements that "regulate" gene expression is methylation: a chemical group that attaches itself to certain places on the DNA strand to promote or limit gene expression. In recent decades, it has been discovered that methylation changes in a predictable way during aging, according to a pattern known as the "epigenetic clock". Once this clock has been established for a given population of individuals, it is therefore possible to deduce an individual's age by looking for the presence or absence of methylation on DNA. All it takes is a few cells, such as skin cells.

A team of top scientists from both regions is involved.

• Pr Frédéric Silvestre and Dr Alice Dennis - UNamur, Belgium
• Dr Krishna Das - ULiège, Belgium
• Dr Jonathan Verreault - Université du Québec à Montréal, Canada
• Dr Stéphane Lair - Université de Montréal, Canada
• Dr Magali Houde - Environment and Climate Change Canada
• Dr Véronique Lesage - Fisheries and Oceans Canada
• Dr Robert Michaud - Group for Research and Education on Marine Mammals (GREMM), Quebec, Canada

The research team will validate this new method and investigate the link with contaminant accumulation, physiological stress and overall health in this threatened population, comparing the ESL population with a healthier population of belugas from the Canadian Arctic.

In summary, this research aims to better understand how biological age, as measured by the epigenetic clock, influences the vulnerability of belugas to environmental stressors and their health.

This project will address fundamental research questions never before explored in beluga whales,

A new PhD student will join the Namur team, under the supervision of Frédéric Silvestre and will work in collaboration with researcher Justine Bélik on the basis of the EpiClock she developed for the mangrove rivulus.

Along with a project on mangrove rivulus in Florida and Belize, and one on fish and invertebrate populations in the Ecuadorian mountains, this is the third scientific project to use Namur researchers' expertise in ecological epigenetics in wild animals to help preserve biodiversity.

Collaborative research F.R.S.-FNRS - FRQ (Fédération Wallonie-Bruxelles - Québec)

The F.R.S.-FNRS has launched PINT-Bilat-P calls for bilateral research projects with the Fonds de Recherche du Québec. These calls are part of a drive to develop strategic partnerships. The aim of this bilateral research program is to create a leverage effect for scientific excellence and to encourage researchers from the Wallonia-Brussels Federation and Quebec to develop innovative joint research projects.

• Long-term effects of pollution in our rivers, oceans and lakes
• Understanding epigenetics to conserve biodiversity

The study of Brucella is one of the areas of microbiology in which UNamur research teams have specialised for more than twenty years. This pathogenic bacteria infects livestock, causing Brucellosis, a disease that can be transmitted to humans through the consumption of unpasteurised dairy products, contact with infected animal tissue or inhalation. It is one of the most widespread zoonoses in the world.

A catalogue of weaknesses

Over the years of research, the team led by Professor Xavier De Bolle, Professor in the Department of Biology, member of the Microorganism Biology Research Unit (URBM) at the University of Namur and investigator at the WEL Research Institute, has been able to establish a kind of “catalogue” of Brucella's weaknesses. 

There are millions of species of bacteria.  It is therefore impossible to study them on a case-by-case basis.  However, they have similar behaviours and functions, which is why a specific bacterium is considered the model: Escherichia coli (or E. coli), an intestinal bacteria found in warm-blooded organisms.  Discovered in 1885, it has been the subject of numerous studies and has therefore become a reference in scientific literature. 

A bacterium such as E. coli or Brucella is like an onion with only two layers (inner and outer membrane) and a central element (the cytoplasm) in which the organism produces everything it needs. It also exports elements to the outside, particularly lipids.  However, these processes are still poorly understood, even for E. coli. Nevertheless, they represent an interesting avenue to explore to reach the heart of the pathogenic bacteria.

This provides valuable information about a new weakness in the pathogen and therefore provides information on how to combat it more effectively.

• Adélie Lannoy (currently post-doc in Toulouse) and Xavier De Bolle (URBM, UNamur – Belgium)
• Marc Dieu and Patsy Renard (UNamur, URBC - Belgium)
• Antonia García Fernández (Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU – Spain)
• Raquel Condez-Alvarez (Department of Microbiology and Parasitology, Instituto de Investigación Sanitaria de Navarra (IdiSNA)University of Navarra – Spain)

The researchers would like to thank the FNRS and the WEL Research Institute for their support in this research. They would also like to thank the ‘Mass Spectrometry – MaSUN’ platform and the ‘Level 3 Biosafety Laboratory – BL3’ technology platform at UNamur for their cutting-edge equipment and expertise.

This work illustrates the cutting-edge expertise developed at UNamur in the field of molecular microbiology, an area in which UNamur has decided to invest by organising a master's degree in molecular microbiology since September 2019. This is a unique master's degree in Europe, taught entirely in English and rooted in research.

• New clues to break through Brucella's armour (02/27/2023) - https://unamur.be/fr/newsroom/de-nouveaux-indices-pour-percer-larmure-de-brucella
• Alison Forrester and Xavier De Bolle awarded grants from the latest FRFS-Welbio call for projects (07/23/2024) - https://unamur.be/fr/newsroom/laureats-dernier-appel-projets-frfs-welbio

Four researchers obtained a mandat d'aspirant enabling them to start doctoral research:

• Ludovic DUBOIS and Niccolò PARDINI from the Faculty of Philosophy and Letters,
• Jordan ABRAS from the Faculty of Economics Management Communication sciencesPo (EMCP)
• Noah DEVEAUX from the Faculty of Science.

Success is also on the cards for the postdoctoral researchers, nine of whom have been awarded a research fellowship for 3 years.

• Audrey LEPRINCE, Ciska DE RUYVER, Dmytro STRILETS and Cinzia TOMASELLI from the Faculty of Sciences
• Nicolas MICHEL, Sébastien VANDENITTE and Manon HOUTART from the Faculty of Philosophy and Letters
• Pierre-Yves HUREL and Sebastian RONDEROS from the Faculty of Economics Management Communication sciencesPo (EMCP).

In addition, two new qualified researchers join our university.

• Marie DELABY in the Biology Department of the Faculty of Science
• Matthieu PIGNOT in the History Department of the Faculty of Philosophy and Letters

Three Namur researchers have also obtained funding from the Télévie call.

• Marc HENNEQUART for research aimed at highlighting new metabolic biomarkers for better detection of pancreatic cancer
• Carine MICHIELS for research into the resistance of glioblastoma to radiotherapy combined with chemotherapy
• Anne-Catherine HEUSKIN for research into understanding the reprogramming of macrophage immune cells in the formation of the tumor microenvironment.

Frédéric SILVESTRE (Faculty of Science, Department of Biology, URBE) has also been awarded funding for a FNRS-FRQ collaborative project with ULiège and Quebec teams from the Université de Montréal and the Université du Québec à Montréal. The aims of this project are to develop a new method of age determination based on molecular modifications (epigenetic clock) in beluga whales (Delphinapterus leucas) from the St. Lawrence estuary in Quebec, and to understand the role of age on contaminant accumulation as well as on their stress levels and health status. This will enable better decisions to be made to improve the recovery of this endangered population. As part of this project, two doctoral theses (one in Namur and one in Montreal) are open. Candidates must be biologists (or degree deemed equivalent) with an interest in conservation and ecotoxicology issues, and with experience in molecular biology (omics) and bioinformatics.

Congratulations to them!