The American Chemical Society (ACS) are reporting research presented at the 243rd National Meeting & Exposition of the ACS about game theory in bacteria. The research investigated chemical signals exchanged between cells, which the press release calls “chat”. The press release reports that:

Faced with drought, radiation, over-crowding or other harsh environmental conditions, B. subtilis engages in quorum sensing, with individual microbes releasing chemical compounds that enable it to check out how their neighbors are responding to the unfavorable environment. Members of a colony of B. subtilis may decide to respond to the stressful environment in one of two ways.

Most become “spores” to enter a “hibernation-like state” until conditions improve. However, “about 1-2 percent” apparently “‘see’ that their neighbors are becoming spores” and enter a transformation into a state called “competency” to use DNA discarded from those undergoing “sporulation” to try to adapt to the environment. Apparently, the research “suggests that the way cells make decisions is consistent with game theory”, with sporulation “like cooperating or confessing” in the Prisoner’s Dilemma, while competency is “a selfish decision that exploits the misfortunes of others”.

Researcher José Onuchic is quoted saying:

Just as in the classic Prisoner’s Dilemma game, the bacteria have to weigh the pros and cons of their decisions. The bacteria make a decision based not only on what it knows about its own stress and environment, but it also has to think about what the other bacteria might do. So this is like the Prisoner’s Dilemma being played with 1 trillion cells in a colony instead of just two people.

Apparently the researchers identified the proteins, genes and other substances involved in making such ‘decisions’ for B. subtilis and how they interact with each other. The next step is determining whether human cells undergo similar processes in health and disease, which may have reveal information about chemical signalling that causes “the uncontrolled division and growth that defines cancer” and other related issues.

Source: Bacteria Use Chat to Play the “Prisoner’s Dilemma” Game in Deciding Their Fate.