Workshop on Systems Biology, Mon, 05 Nov, 2007
Speaker: Stefan Schuster
Abstract
Studying competitive and cooperative strategies in the interaction between different microbial species is of relevance for optimizing biotechnological setups. Two species of micro-organisms that use the same nutrient, but may choose between two different biochemical pathways of energy conversion, can be studied by methods from game theory. The pathways are considered as distinct strategies to which payoffs can be assigned. For each species, the payoff does not only depend on the strategy adopted by that species but also on the strategy of the other species. Studying the tradeoff between rate and yield of energy conversion on the basis of evolutionary game theory reveals that competition for shared energy resources should lead to the evolution of fast but non-economical energy conversion, although slow but efficient energy conversion would be more beneficial for all users of the resource. The former situation is the stable Nash equilibrium of that game, while the latter situation is the Pareto optimum. The Nash equilibrium paradoxically implies that the user's tendency to maximize their fitness actually results in a decrease of their fitness. Thus, the whole can be worse than the sum of its parts, as in arms race. The resulting evolutionary dilemma is analogous to the ”Tragedy of the Commons”. Therefore, cooperative behaviour is unlikely to occur, unless additional factors interfere. In fact, the yeast Saccharomyces cerevisiae uses a competitive strategy by fermenting sugars even under aerobic conditions. Several ideas on possible scenarios of transition to cooperative behaviour are discussed. Spatial and stochastic effects appear to play a role in this transition.
References
T. Pfeiffer, S. Schuster, S. Bonhoeffer. Science 292 (2001) 504-507.
T. Frick, S. Schuster. Naturwissenschaften 90 (2003) 327-331.
T. Pfeiffer, S. Schuster. Trends Biochem. Sci. 30 (2005) 20-25.
URL: www.ricam.oeaw.ac.at/specsem/ssqbm/participants/abstracts/index.php
This page was made with 100% valid HTML & CSS - Send comments to Webmaster
Today's date and time is 04/18/24 - 07:37 CEST and this file (/specsem/ssqbm/participants/abstracts/index.php) was last modified on 12/18/12 - 11:01 CEST