Wednesday, March 26 at 12 p.m.
The College of Science and Department of Physics present “Decision Making at the Cell Level: From microorganisms to possibly cancer” featuring José Nelson Onuchic. Dr. Onuchic is the Harry C. and Olga K. Weiss Chair of Physics, a professor of physics and astronomy, chemistry, and biochemistry and cell biology, and co-director of the Center for Theoretical Biological Physics (CTBP) at Rice University.
In nature, bacteria are living in large colonies whose number of bacteria may reach up to 100 times the number of people on Earth. The new research showed how under life alarming conditions the bacteria in the colony communicate via chemical messages and how each bacterium performs a sophisticated decision process by using a specialized network of genes and proteins. This complex network enables to perform complex calculations to assess the prose and cones of the different choices using guided by a new principles of game theory.physics
Many bacteria respond to extreme stresses, such as starvation, poisons, damage to DNA, etc. by creating spores – dormant versions that are highly resistant. The spores wait and germinate if/when the stress is removed. This process involved more than 500 genes, and takes about 10 hours in the studied bacteria – Bacillus subtilis. Sporulation ends with the death of the mother cell after a copy of the DNA is stored in a special capsule – the spore. The mother cell then break open and its DNA and left over proteins are released to the environment. The bacteria on the road towards sporulation have the option to decide to change their fate and escape into a different state called competence.
This is where game theory enters. Bacteria game theory if far more advanced than the well-known case of the Prisoner Dilemma. Classic prisoner’s dilemma usually told for two prisoners given them an offer – if one does not admit the crime and second, it will be admitted two years’ imprisonment and not admitted will receive 6 years in prison. If they admit – they will get 4 years, and none of them admit, they were free. “Prisoner’s dilemma” here is more complex,” each bacterium must decide whether to become a spore (cooperate) or escape into competence (take advantage of the others) while it has a limited time to decide when a clock is ticking.
Connections between bacteria decision-making in a colony with cancer will be discussed. The idea that in both bacterial colonies and growing tumors, genetic variability is selected by local conditions so as to increase growth will be explored.