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PENN STATE iGEM 2008
Welcome to the Penn State iGEM 2008 team website. We have been working hard at a few different projects for this year's competition. Starting this summer we began working trying to create different types of biosensors that use human nuclear hormone receptors to recognize potentially harmful ligands. We also have been finishing up one of last year's projects which is amied at more reaching efficent bioproduction by altering how E. Coli selects between utilizing 5 and 6 carbon sugars. Please explore our website to find out more about us and our projects!
If there are any questions or comments about the information on this site please contact us at gjt5001@psu.edu.
| Hormone Prescreening E. coli
Our project aims to construct a bio sensor which will ultimately serve as a pre screening tool to detect the presence of phthalates in water sample. Recently phthalates have been shown to cause negative health effect in humans; some phthalates are even though to be carcinogenic. Analytical detection methods for these compounds are compound specific as well as very costly. Having a simple, and cheep tool to screen for phthalates as a general class of compounds would eliminate some of the cost and time involved in current detection methods.
We use the natural human nuclear hormone receptor protein that recognizes phthalates as an agonist (hPPARα), and expressing it heterologously in Escherichia Coli. Because of the complexity of this mammalian protein, expressing it in a prokaryote is difficult. We have two different strategies to express hPPARα and using it to detect phthalates in E. Coli.
Smart Fold Reporter
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Smart Fold Reporter is the subproject for the first strategy we are trying to express hPPARalpha in E. coli. This project uses altered growth conditions such that this nuclear hormone receptor protein can be successfully epressed and used to transcriptionally report for the presence of phthalates. |
Nuclear Fusion
Nuclear Fusion is our second approach to constructing a phthalate detection system in E. coli. In this project we use just the ligand binding domain of hPPARα fused to thymidylate synthase (TS). Binding of the phthalate ligand to this chimeric protein activates TS. When this construct is placed in a TS diffident strain, only E. coli in the presence of a hPPARalpha agonist will survive. |
Diauxie Elimination: Two spoons full of sugar.
If ethanol fuel were produced from cellulosic biomass using E. coli, about half of the biomass would not be used. Cellulosic biomass, which is cheap and abundant, coming from plant waste and the like, contains glucose and xylose sugars in relatively equal ratios, while e. coli preferentially metabolizes glucose before any other sugar.
In this project we attempt to eliminate this phenomenon called diauxie by getting our cells to utilize both sugars at the same time. Solving this problem will lead to more efficent use of cellulosic biomass including moving towards the future of bioproduction: continous processes.
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