Tunable Synthetic Ecology

View all posters

Luciano Gastn Morosi, Bush, A; Grande, A; Sabio, G; Snchez, I; and Nadra, A

Faculty of Exact and Natural Sciences - University of Buenos Aires, Argentina

Synthetic biologists engineer microorganisms using standardized DNA parts to achieve a desired behavior. Since the number of components that can be assembled into a single cell is limited, we sought to create a stable microorganism co-culture with defined, tunable proportions of two different cell types. Such a co-culture could be used as a “multicellular chassis” for synthetic biology. 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 (Trp) and histidine (His) to each other. Mathematical modeling identified the amino acid secretion rates as critical parameters to achieve growth and auto-regulation at fixed strain proportions. To implement the crossfeeding system we design and created four novel genetic devices, which code for secretable peptides rich in either Trp or His, with a cell penetrating sequence. Experimental validation showed that the devices could increase the Trp secretion rate and enable co-culture growth. 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.