Research team at Freie Universität Berlin discovers surprising differences in ageing bacterial cells

A research team at Freie Universität Berlin led by biologist Dr Ulrich Steiner has gained surprising insights into ageing in bacteria. In a new study, which has now been published in the renowned journal Science Advances, the team shows that even genetically identical bacterial cells living in the same environment react differently during the ageing process and that there are even differences in ageing within different cell regions.

Berlin, November 12, 2024 The research could not only contribute to a better understanding of the basic mechanisms of ageing, but also provide approaches for research into the survivability and resistance of bacteria to environmental influences and antibiotics. The study entitled ‘Progressive decline in old pole gene expression signal enhances phenotypic heterogeneity in bacteria’ is available at (https://www.science.org/doi/10.1126/sciadv.adp8784).

‘Human life expectancy has been increasing continuously for 150 years, by around 3 months per year. Nevertheless, we still only have a rudimentary understanding of the mechanisms of ageing,’ explains Dr Audrey Proenca, first author of the study. Simple organisms such as bacteria have long been considered ‘immortal’. Since bacteria divide into two equal parts and bacterial strains live forever, scientists long assumed that bacteria could not age. However, recent studies show that there is an astonishing variability in the ageing process.

Even genetically identical cells in the same environment behave differently: some grow faster; others produce large quantities of certain proteins that are completely absent in others. In order to understand the ageing dynamics of bacterial cells, scientists must therefore look deeper into the cells.

Study provides a better understanding of cell ageing

The research group for evolutionary demography at Freie Universität Berlin therefore investigated the behaviour and ageing dynamics of the bacterial species Escherichia coli over more than 100 generations. ‘We have discovered a new aspect of bacterial ageing that shows how the ageing process progresses in individual bacterial cells,’ says Dr Audrey Proenca, first author of the Science Advances study. Although E. coli mother cells appear optically identical to their daughter cells, each mother cell retains an ‘old pole’ – the older end of the rod-shaped cell – and passes on a ‘new pole’ to its daughter cell. Using fluorescent proteins, the research team was able to observe that the ‘old poles’ of the mother cells become darker and darker as they age, indicating that fewer and fewer new proteins are being produced there. In contrast, this effect was not observed in the daughter cells. ‘The asymmetry between mothers and daughters increases over time, which in turn shows that bacteria do not divide and age symmetrically,’ explains the biologist.

‘We were also surprised that this ageing process takes place within a mother cell, between the poles,’ emphasises research group leader Dr Ulrich Steiner.

The new research results provide a better understanding of ageing and cellular diversity in simple organisms. The study shows how ageing can increase diversity within a single bacterial population and could also provide important information on the ageing of human cells and the fight against age-related diseases in the future. Beyond ageing effects, this also opens up new perspectives for research into mechanisms that could contribute to survivability and resistance to stress and antibiotics, among other things.

Further information

Die Studie mit dem Titel „Progressive decline in old pole gene expression signal enhances phenotypic heterogeneity in bacteria“ ist abrufbar unter: (https://www.science.org/doi/10.1126/sciadv.adp8784).

Mehr zur Forschungsgruppe „Evolutionary Demography Group“ der Freien Universität Berlin: (https://www.bcp.fu-berlin.de/en/biologie/arbeitsgruppen/zoologie/ag_steiner/index.html)

Originalpublication:

Die Studie mit dem Titel „Progressive decline in old pole gene expression signal enhances phenotypic heterogeneity in bacteria“ ist abrufbar unter: (https://www.science.org/doi/10.1126/sciadv.adp8784).

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