Francisco Dionisio

Evolutionary Ecology of Microorganisms

Coordination activities

Research
Funded Projects	Explanation of Projects	Other Projects
The role of commensal bacteria in the spread of antibiotic resistance genes. 2008-2010 (PTDC/BIA-BDE/66180/2006). BIOCONTRACT - Cooperation in mutualisms: contracts, markets, space, and dispersal. 2008-2010 (European Science Foundation - EUROCORES - TECT) Mathematical models of evolutionary processes. 2007-2010 (PTDC/MAT/66426/2006).	The aim of the project “The role of commensal bacteria in the spread of antibiotic resistance genes” is to perform a systematic study of the rate of transfer of several conjugative plasmids between different bacterial strains belonging to different species. Previous studies (Dionisio et al Genetics 2002) have shown that, although most strains are poor donors of a given conjugative plasmid, some strains exhibit a strong donor ability of this plasmid. Indeed, in this study - performed with sixteen enterobacterial strains, donor abilities of this plasmid spanned at least a million fold. Consequently, the presence of very efficient donor cells amongst bacterial populations can accelerate plasmid transfer by several orders of magnitude. We this new project, our expectations are that a systematic knowledge of plasmid transfer rates represents precious information with direct medical and environmental consequences. Although the significance of cross-species transfer of antibiotic-resistance genes and conjugative plasmids has been fully recognized, the role of amplifier non-pathogenic bacteria in this progression is still unknown. Principal Investigator: Francisco Dionisio Collaborators: Ana Maria Reis and Max Mergeay	Pathogens as biological weapons Epistasis in bacteria (collaboration with Isabel Gordo and it is the focus of Ph.D. thesis of Sandra Trindade) Tragedy of the Commons among bacteria Cost of Antibiotic Resistance
	The aim of the project BIOCONTRACT is to study cooperation in mutualisms. In biology, a mutualism is an interaction between species that results in increased fitness for both partners. BIOCONTRACT applies contract theory from economics in order to investigate how the evolution of ‘natural contracts’ can distribute the benefits of mutualism among partners. The project draws and expands upon the economic theory of self-enforcing contracts to investigate how mutualisms persist in the face of potential exploitation by cheaters (organisms that reap the benefits of mutualism but do not reciprocate). BIOCONTRACT parameterizes the models that are developed by using data from several empirical systems. In so doing, it aims to describe general mechanisms that promote and maintain cooperation in diverse biological systems. Principal Investigators of BIOCONTRACT: • Ulf Dieckmann, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria • Francisco Dionisio, Universidade de Lisboa, Portugal • Drew Fudenberg, Harvard University, Cambridge, USA • Douglas W. Yu, University of East Anglia, Norwich, UK • Jerry Green, Harvard University, Cambridge, USA • Jérôme Orivel, Université Toulouse 3, France • Naomi Pierce, Harvard University, Cambridge, USA (leader) • Istvan Scheuring, Eötvös University, Budapest, Hungary
	With the project “Mathematical models of evolutionary processes”, we will use mathematical models and computer simulations to study cooperation and conflict between individuals and/or genes. Principal Investigator: Fabio A.C.C. Chalub Collaborators: Francisco Dionisio and Jorge M. Pacheco