Bacteria are simple organisms that share the same DNA sequence. However, they can exhibit a wide range of behaviours. Biophysicist Fotios Avgidis investigated how and why this is the case.
Avgidis and his colleagues discovered that bacteria exploit variability in gene expression (or "noise") as a strategy to cope with changing environments. Using a combination of experiments and mathematical modelling, they show that this molecular noise can explain the observed variability in the behaviour of bacteria. This behavioural variability allows bacteria to be pre-adapted to a range of potential future environments.
Self-organisation near a critical point
The researchers also discovered that bacterial chemoreceptors – large proteins responsible for detecting environmental signals – self-organise near a critical point, the boundary between order and disorder. Operating near this critical point allows them to maximize sensitivity to environmental signals while minimizing response time.
Chemotherapy and antibiotics
This knowledge can be useful in treating diseases, which often arise by the presence of outliers. Examples are cancer cells that evade chemotherapy or bacteria that are resistant to antibiotics.
"By understanding the sources of diversity in biological behaviour, we can develop more effective strategies to eliminate these outliers," says Avgidis. “This will allow us to design chemotherapy drugs and antibiotics that specifically target these rare, resilient cells.”
Avgidis will defend his PhD thesis on June 6.