Synthetic Ecology (a tunable co-culture)

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Alan Bush, Manuel Giménez, Alicia Grande, Luciano Morosi, Vernica Parasco, Alejandra Parreo, Mario Rugiero, Germn Sabio, Alejandro Colman-Lerner, Alejandro D. Nadra, Ignacio E. Snchez

FCEN - UBA, Argentina

Synthetic biologists engineer biological devices by assembling standardized building blocks into an organism that is used as “chassis”. Since the number of components that can be assembled into a single chassis is limited, we aimed at the creation of a stable microorganism co-culture with defined, tunable proportions of two different strains. Such a co-culture could be used as a multicellular chassis for synthetic biology. FINDINGS: This poster presents work done largely by the Buenos Aires team participating in the 2012 International Genetically Engineered Machines (iGEM) competition. We designed a tunable co-culture of two auxotrophic budding yeast strains that feed the amino acids tryptophan and histidine to each other. Mathematical modeling let us identify both the dependence of strain populations on amino acid secretion rates, and the amino acid secretion rates required for auto-regulated co-culture growth. We implemented our design in four novel amino acid crossfeeding devices, which use sequence tags for peptide secretion and cell penetration of a peptide payload. Experimental validation showed that the design of tryptophan secretion was successful and that the crossfeeding devices enhance co-culture growth. CONCLUSIONS: Our amino acid crossfeeding devices show promise as a tunable standard tool for synthetic biology and for the quantitative study of mutualistic interactions between microorganisms.