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University of Basel

Sophisticated swarming: Bacteria support each other across generations

Bacterial swarm on a petri dish
Swarm of Bacillus subtilis bacteria on an agar plate. (Colorized image: Biozentrum, University of Basel

When bacteria build communities, they cooperate and share nutrients across generations. Researchers at the University of Basel have been able to demonstrate this for the first time using a newly developed method. This innovative technique enables the tracking of gene expression during the development of bacterial communities over space and time.

21 November 2023 | Heike Sacher, Katrin Bühler

Bacterial swarm on a petri dish
Swarm of Bacillus subtilis bacteria on an agar plate. (Colorized image: Biozentrum, University of Basel

In nature, bacteria usually live in communities. They collectively colonize our gut, also known as the gut microbiome, or form biofilms such as dental plaque. Living in communities provides many advantages to the individual microbes. They are more resilient against adverse environmental conditions, conquer new territories and benefit from each other.

Analyzing microbial communities in space and time

The development of bacterial communities is a highly complex process where bacteria form intricate three-dimensional structures. In their latest study published in Nature Microbiology, the team led by Professor Knut Drescher from the Biozentrum of the University of Basel has investigated the development of bacterial swarm communities in detail.

They achieved a methodological breakthrough enabling them to simultaneously measure gene expression and image the behaviour of individual cells in microbial communities in space and time.

Bacteria provide resources for future generations

"We used Bacillus subtilis as a model organism. This ubiquitous bacterium is also found in our intestinal flora. We have revealed that these bacteria, which live in communities, cooperate and interact with each other across generations," explains Professor Knut Drescher, head of the study. "Earlier generations deposit metabolites for later generations."

They also identified different subpopulations within a bacterial swarm, which produce and consume different metabolites. Some of the metabolites secreted by one subpopulation become the food for other subpopulations that emerge later during swarm development.

Distribution of tasks within the community

The researchers combined state-of-the-art adaptive microscopy, gene expression analyses, metabolite analyses, and robotic sampling. Using this innovative approach, the researchers have been able to simultaneously examine gene expression and bacterial behavior at precisely defined locations and specific times as well as to identify the metabolites secreted by the bacteria. The bacterial swarm could thus be divided into three major regions: the swarm front, the intermediate region and the swarm center. However, the three regions display gradual transitions.

Original publication

Hannah Jeckel et al.
Simultaneous spatiotemporal transcriptomics and microscopy of Bacillus subtilis swarm development reveal cooperation across generations.
Nature Microbiology (2023), doi: 10.1038/s41564-023-01518-4

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