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From 2014.igem.org

HOME PROJECT PARTS TEAM NOTEBOOK SAFETY

What? This summer, the UPenn 2014 iGEM team worked to engineer a complex genetic system that utilizes quorum sensing in bacteria. Our novel genetic pathway is designed to incorporate two orthogonal, or completely independent quorum sensing molecules to regulate the population levels of E. Coli and Streptomyces griesius in a co-culture. The population levels are determined by controlling the quorum sensing signals through external stimuli. Heat and IPTG act as tuning dials to dictate the exact composition of the composite population; adjustments can result in desired population ratios of ''E. Coli'' and ''Streptomyces griesius." Top

How? Our project will incorporate a genetic circuit with two orthogonal pathways that regulates the population level of E. Coli and Streptomyces. Upon adding necessary inputs to our system, tetracycline will be produced in the Streptomyces and luxS will be produced in the E. Coli. Both these products act as quorum sensing molecules. The tetracycline strain 1 will communicate with strain 2 causing the population to grow due to the production of methionine, an essential amino acid. Simultaneously, the luxS will communicate with strain 1 to produce a second essential amino acid, lysine, thereby fostering the growth of strain 1. The population level of strain 1 can be controlled with heat, and the growth of strain two is mitigated by IPTG. Top

Why? The largest obstacle the medical field and the drug industry face today are the lack of testing options for new drugs and the latest treatments. Of the many animal models and other experimental methods that exist, none simulate the complexity of the microenvironments found in the human body like the gut or the mouth. This makes the testing and distribution of the most novel and potentially life saving treatments difficult and time consuming. At the same time, these testing methods may not provide the most accurate results of how treatments will affect the human body. Top

Microbiome? Microbiomes are small scale environments found in nature that are filled with bacterial ecosystems. These miniscule systems are found in the soil, water sources, and even in the human body. The ecosystems found in microbiomes are organized by bacterial quorum sensing, chemical signaling between bacteria of the same and different species. By using quorum sensing, bacteria can tell species to grow and divide, secrete a particular compound, or to reduce populations by dieing. In this way, quorum sensing tunes the microenvironment by regulating the populations of certain bacteria by telling some to grow and others to die. Top

How will our project help? The goal of our project is to use our genetic circuit that uses quorum sensing to control the populations of two different strains of bacteria in a coculture. By exploiting quorum sensing in a similar way bacteria found in the gut, mouth, and on skin do, we hope to create a microbiome that can someday be used to simulate those of the body. This microbiome will be the first step in using synthetic biology to create more accessible, safer, and more accurate drug testing platforms. Top