Belgian research couple rewarded for their work on incurable diseases
The Gagna & Van Heck International Prize for incurable diseases is awarded for the first time to a Belgian team.
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Predator, vampire... worthy of Halloween creatures, the names of Géraldine Laloux's research projects refer to much smaller but very real living beings: bacteria. But not just any bacteria. Bacteria that attack other bacteria to survive and proliferate. The aim is to eventually use their strategies to reinforce the effect of antibiotics or as new therapeutic means against bacteria of public health concern.
After being awarded an ERC Starting Grant in 2019, which ends at the end of 2024, the young researcher from UCLouvain's Institut de Duve has just been awarded an ERC Consolidator grant to continue her exciting investigations into these atypical bacteria. “During the ERC Starting Grant project, we focused on the life cycle of the bacterium Bdellovibrio bacteriovorus. It only proliferates inside other bacteria,” explains Géraldine Laloux. The prestigious grant for her “Predator” project enabled her to set up a team and acquire two state-of-the-art microscopes for microscopy on living bacterial cells. “We have developed tools, such as fluorescent markers, that enable us to observe the fundamental processes of this bacterium directly”, continues the researcher.
Replication of genetic material (DNA), distribution of this material between daughter cells, cell division, growth... the team has dissected the predatory bacterium's cell biology. “In addition to the fact that it proliferates in other bacteria, it grows in a very particular way: it forms a long filament, like a spaghetti, and separates into a variable number of daughter cells, whereas a classic bacterium divides into two daughter cells”, explains Géraldine Laloux. Among the observations made during this research project, the scientists discovered that the growth of Bdellovibrio bacteriovorus and the number of daughter cells it produces depend on the size of the host bacterium in which it proliferates. “We have begun to understand how this bacterium grows into a filament, and how it organizes proteins along the filament to create daughter cells capable of reproducing the bacterial cycle in turn,” reveals the researcher. The prey's attack and invasion depend on the position of these proteins, which the mother bacterium has placed during its growth. Géraldine Laloux's team has begun to elucidate the dynamics of these protein positions.
These promising results enabled Géraldine Laloux to obtain an ERC Consolidator grant to pursue her investigations. She has named this new project “Vampire”. Why? ”Because we're going to incorporate a new model of predatory bacteria into our research: bacteria that vampire other bacteria by attaching themselves to their surface and sucking out their contents. They digest it, recover nutrients, grow and generally produce three daughter cells”, explains the scientist. This bacterium is Bdellovibrio exovorus.
Over the next 5 years, Géraldine Laloux's team will be examining and unravelling the molecular aspects of interactions between prey and the two types of predatory bacteria. “We'd like to understand how they recognize, attach, enter or remain attached to the surface of their prey”, emphasizes the winner of the ERC Consolidator grant. As for Bdellovibrio bacteriovorus, the researchers would like to reveal how its cycle adjusts according to the interactions and digestion of its prey. “How does this predator 'know' that it's inside a small or large bacterium, and how does it 'know' that it should stop growing and release its daughter cells?” asks Géraldine Laloux.
In a world where antibiotics are losing their effectiveness due to bacterial resistance to these drugs, this research will help identify the molecular weapons that bacteria use against each other, and inspire scientists to create innovative strategies to combat bacteria. Either in combination with antibiotics (as adjuvants) or as new therapeutic means, for example by exploiting the toxins that these predator/vampire bacteria use to attack their prey.
Géraldine Laloux has also been a WelRi Investigator since 2024.