Dr. Ulf Liebal

Bacterial Stress Response: Decisions at the Organism-Environment Interface

"The way simple bacteria interact with their environment teaches us about the complexity of nature. Can we use this information to our benefit?"

To survive, bacteria have to adapt to changing environmental conditions like heat, desiccation, and starvation. They sense changes in the environment and adapt their way of life: becoming greedy with expenses, control of proper functioning of the intracellular components, preparing for dormancy.
The question we focus on is: How is the information of a challenging environment transported how is it modified on its way, how does it lead to the activation of genes and how is the signal muted?

The stress responses enable bacteria to sustain their life functions. This sheds light on the organism-environment relationship. We can use this knowledge to improve biotechnological production of chemical products as well as in the design of new therapeutics for bacterially related diseases.
We studied how a bacterium changed its way of living during the transition to starvation. We followed a particular behaviour which is only transiently activated. Why this behaviour is transient is not clear, but we could add new information about this. During that behavioural response a huge protein complex is activated that integrates the information of the stresses it receives. This complex makes decisions not unlike a computer and we tested hypotheses how the structure supports its functions.

Our results show that the stability of the protein which we used to asses the stress state of the cell is changing during stress. Proteins might generally be subject to increased turnover at the transition to starvation. We found that the computer-like stress integrating complex would not be able to perform its function if there would be weaker associations. As this complex is also used by pathogenic bacteria to activate disease related genes, knowledge about it will lead to new therapeutic drugs.