Using Escherichia coli as a model, Ivan Matic and François Taddei documented a novel mode of aging involving the clonal descendants of this bacteria. This discovery is essential to deciphering the molecular mechanisms of aging in humans.

The mystery of aging

Aging has the same effects on all multicellular organisms: mortality rate increases exponentially, the probability of having offspring decreases and biological functions progressively deteriorate. However, little is known about the molecular mechanisms that control the dynamics of aging.

In contrast, bacteria do not go through a juvenile stage, nor do they develop towards reproductive maturity. But are bacteria immortal? They appear to have an infinite capacity to reproduce, replicating themselves and splitting into two seemingly identical clones. Their death seems accidental, and is caused by other bacteria or viruses, toxic environments or lack of food.

However, Ivan Matic and François Taddei’s research on the Escherichia coli bacterium has uncovered a novel form of aging.

Clonal descent or inherited old age

With the grant from the Liliane Bettencourt Prize for Life Sciences, these researchers have developed a camera and microscope that can monitor the reproduction of Escherichia coli over several generations.

They observed that these rod-shaped bacteria have two poles: old biological material on one side and more recent material on the other. This asymmetry is due to their mode of reproduction. Before dividing, the bacterium makes a copy of its genetic material in its centre. Then, it splits in two down the middle.

Each daughter bacterium inherits part of the new genetic material produced during division. However, one of the offspring will also inherit the oldest maternal pole, while the other receives the youngest. The older a bacterium’s old pole, the slower it grows, the more fragile it is, and the more difficulty it has reproducing, which is the very definition of aging. The researchers were also surprised to discover that all 88 granddaughters of the same cell can die simultaneously.

Scientific and therapeutic perspectives

Not only does this work call into question the way Escherichia coli is used as a model by thousands of laboratories worldwide, but it is also paving the way to understanding the molecular mechanisms of aging in humans.

The research team has already found molecular defects in the “old poles” of bacteria, similar to those observed in the brains of patients with neurodegenerative diseases. Furthermore, the stem cells that renew our tissues use a similar mode of division as those of these bacteria.

Finally, this research could have medical applications, as the mechanisms involved in bacterial degeneration may constitute promising therapeutic targets.

François Taddei in a few words

François Taddei was initially trained as an engineer at the Ecole Polytechnique. His focus shifted to genetics during his PhD at Paris-Sud University, where he was supervised by Miroslav Radman and worked alongside Ivan Matic, who was completing his thesis in the same laboratory. These encounters marked the start of a successful scientific collaboration between the three researchers, which led to the foundation of the TaMaRa Laboratory at the Institut Jacques Monod, Paris. 

The Liliane Bettencourt Prize for Life Sciences allowed François Taddei to continue his innovative research on the Escherichia coli bacterium, which led to the discovery of a novel mode of aging: clonal descent. 

In 2005, he co-founded the CRI in Paris, now the Learning Planet, to promote pedagogical innovation and develop interdisciplinary training in life sciences, physics, chemistry, mathematics, computer science and social sciences.

©Philippe Caron pour la Fondation Bettencourt Schueller

  • 1995 PhD in Cellular and Molecular Genetics, Paris-Sud University

  • 1996 Post-Doctoral Fellowship in the laboratories of Dr John Maynard Smith, and Dr Pierre-Henri Gouyon

  • 1997 Inserm Researcher

  • 2000 Head of the Evolutionary Systems Biology team, Molecular Evolutionary and Medical Genetics Laboratory, Paris Descartes University

  • 2003 Inserm Prize for Fundamental Research and Liliane Bettencourt Prize for Life Sciences

Ivan Matic in a few words

Ivan Matic first encountered mutagenesis during his graduate studies in Croatia, where he examined the effects of an alkaline agent on the bacteria responsible for Salmonella and Escherichia coli.

In 1995, he completed a PhD in molecular and cellular genetics, joining Miroslav Radman’s laboratory at the same time as François Taddei. The three researchers cemented their scientific collaboration by founding the TaMaRa laboratory at the Institut Jacques Monod. Together, they have made vital discoveries regarding the evolutionary and adaptive implications of genetic mutations and the mechanisms of aging.

Ivan Matic specializes in DNA repair mechanisms and molecular responses to stress and aging. To combat the emergence of new infectious diseases and solve the problem of antibiotic resistance, he has made it his mission to understand how molecular mechanisms and environmental fluctuations have an impact on these fundamental evolutionary processes.

©Philippe Caron pour la Fondation Bettencourt Schueller

  • 1995 PhD in Cellular and Molecular Genetics, Paris-Sud University

  • 1995 CNRS Researcher, Institut Jacques Monod, Paris

  • 2001 CNRS Research Director, Head of the Molecular Evolutionary and Medical Genetics Laboratory Team, Paris Descartes University

  • 2003 Liliane Bettencourt Prize for Life Sciences

Liliane Bettencourt Prize for Life Sciences

The Liliane Bettencourt Prize for Life Sciences rewards each year a researcher under the age of 45 for the excellence of their work and their remarkable contribution to their field of scientific research. This prize is awarded, depending on the year, to a researcher based in France or working in another European country. Twenty-seven winners have been awarded since 1997. From 2023, prize rewards the laureate up to 100,000 euros.

All the award-winners