Microbes may be smarter than we think. A new study by Princeton University researchers shows for the first time that bacteria don’t just react to changes in their surroundings — they anticipate and prepare for them. The findings, reported in the June 6 issue of Science, challenge the prevailing notion that only organisms with complex nervous systems have this ability.
“What we have found is the first evidence that bacteria can use sensed cues from their environment to infer future events,” says Saeed Tavazoie, an associate professor in the department of Molecular Biology, who conducted the study along with graduate student Ilias Tagkopoulos and post-doctoral researcher Yir-Chung Liu.
The research team, which included biologists and engineers, used lab experiments to demonstrate this phenomenon in common bacteria. They also turned to computer simulations to explain how a microbe species’ internal network of genes and proteins could evolve over time to produce such complex behavior. … Remarkably, within a few hundred generations the bugs partially adapted to this new regime, and no longer turned off the genes for aerobic respiration when the temperature rose. “This reprogramming clearly indicates that shutting down aerobic respiration following a temperature increase is not essential to E. coli’s survival,” says Tavazoie. “On the contrary, it appears that the bacterium has “learned” this response by associating specific temperatures with specific oxygen levels over the course of its evolution.” Lacking a brain or even a primitive nervous system, how is a single-celled bacterium able to pull off this feat? Whereas higher animals can learn new behavior within a single lifetime, bacterial learning takes place over many generations and on an evolutionary time scale, Tavazoie explains. – sd
Much of our intelligence is inherited as instinct.