Microbes capable of sophisticated reasoning?

It is a known fact that microbes can come up with simple responses to changes in their environment, such as acidity fluctuations, by altering their internal workings. But sophisticated reasoning? Systems biologist Saeed Tavazoie of Princeton University wanted to know if microbes were capable of more sophisticated reasoning. He along with his colleagues created an environment inhabited by evolving virtual bugs. The organisms "learnd" that certain signals preceded the arrival of food and came up with pre-emptive metabolic responses. Even when the signal combinations grew more complex, the population was able to evolve the correct responses. Extensive work was done on bacterium Escherichia coli. When the researchers turned up the heat in a dish of E. coli, the bugs narrowed down activity in genes that normally operate in high-oxygen conditions. The true test came when the team reversed the normal association, growing the bacteria in conditions in which high oxygen levels followed temperature increases. Less than 100 generations later, the bacteria stopped turning on their low-oxygen response after exposure to high temperatures, giving a clue that they had evolved to break the association. The work opens up exciting possibilities to explain puzzling behaviour of microbial pathogens, which could be using predictive signals to change their cell surfaces and avoid a host's impending immune attack.

More details can be had from the latest issue of Science magazine

Predictive Behavior Within Microbial Genetic Networks

Ilias Tagkopoulos ¹, Yir-Chung Liu ², Saeed Tavazoie ^2*

¹ Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
² Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.