IGEM:VGEM/2007/Projects

Projects

We have decided to focus on two of the following projects for the remainder of the summer, Bactierla Melanogenesis and Butanol Biosynthesis.

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Bacterial Melanogenesis

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This project is an extension of work that was done at Biosource Genetics Corporation in 1990. What we would like to do is program bacteria to produce melanin in response to a red light stimulus. This inducible melanin production has various applications including making melanin for monitoring cellular processes. In this way, melanin would serve as a biomarker or indicator similar to the GFP but would be easily visible to the naked eye.

References

• Melanin production in Escherichia coli from a cloned tyrosinase gene by Della-Cioppa G, Garger SJ, Sverlow GG, Turpen TH, Grill LK.
• Synthetic biology: engineering Escherichia coli to see light by Levskaya A, Chevalier AA, Tabor JJ, Simpson ZB, Lavery LA, Levy M, Davidson EA, Scouras A, Ellington AD, Marcotte EM, Voigt CA.

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Butanol Biosynthesis

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Coming up with alternative fuels is a real-world problem. We're interested in using cheap, renewable feedstock to power efficient biofuel production. More to come!

References

• Proteorhodopsin photosystem gene expression enables photophosphorylation in a heterologous host by DeLong et al
• Light-powering E. coli with proteorhodopsin
• Insights into metabolic properties of marine bacteria encoding proteorhodopsins
• Complete cellulase system in the marine bacterium Saccharophagus degradans strain 2-40T by Weiner et al
• Saccharophagus degradans, a versatile marine degrader of complex polysaccharides
• Plant Carbohydrate Scavenging through TonB-Dependent Receptors: A Feature Shared by Phytopathogenic and Aquatic Bacteria
• Improvement of Cellulolytic Properties of Clostridium cellulolyticum by Metabolic Engineering
• Butanol fermentation research: upstream and downstream manipulations
• Butanol production from agricultural residues: Impact of degradation products on Clostridium beijerinckii growth and butanol fermentation
• Bioproduction of butanol from biomass: from genes to bioreactors
• Dynamics of Genomic-Library Enrichment and Identification of Solvent Tolerance Genes for Clostridium acetobutylicum
• Butanol Production from Corn Fiber Xylan Using Clostridium acetobutylicum
• Bacterial acetone and butanol production by industrial fermentation in the Soviet Union: use of hydrolyzed agricultural waste for biorefinery
• Butanol Production by a Butanol-Tolerant Strain of Clostridium acetobutylicum in Extruded Corn Broth
• Challenges in engineering microbes for biofuel production by Stephanopoulos
• Metabolic engineering by Stephanopoulos
• Global physiological understanding and metabolic engineering of microorganisms based on omics studies by Park et al

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Ethylene Biosensor

NOTE: This project has been put on the back burner.

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During one of our brainstorming sessions we were discussing possible biosensors and came up with a fairly practical project idea: an ethylene biosensor. Why sense ethylene? Mature fruit produce and release ethylene as they ripen. Measuring the concentration of gaseous ethylene on or near the surface of the ripening fruit would allow for the indirect measurement of its degree of ripeness.

References

• The ethylene gas signal transduction pathway: a molecular perspective by Johnson PR, Ecker JR.
• Molecular biology of fruit maturation and ripening by Giovannoni J.
• Association of the Arabidopsis CTR1 Raf-like kinase with the ETR1 and ERS ethylene receptors by Karen L. Clark
• The ethylene-receptor family from Arabidopsis structure and function by Anthony B. Bleecker
• A strong constitutive ethylene-response phenotype conferred on Arabidopsis plants containing null mutations in the ethylene receptors ETR1 and ERS1 by Xiang Qu
• The Arabidopsis Book by G. Eric Schaller

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Synthetic Biological Clock

NOTE: This project has been put on the back burner.

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The synthetic biological clock was one of our earliest project ideas and involves the coupling of Elowitz and Leibler's repressilator system to some actuator such as fluorescence or aroma generation. We would like to link MIT's 2006 iGEM project to the repressilator and create an aroma therapy clock in addition to linking green, yellow and red fluorescent proteins to the repressilator to make a molecular traffic light. Future applications of controlled synthetic oscillatory systems include internal, autonomous drug delivery technology.

References

• A synthetic oscillatory network of transcriptional regulators by Elowitz MB, Leibler S.
• MIT's 2006 iGEM Project

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Cellular Photosignalling

NOTE: This project has been put on the back burner.

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This system incorporates the idea of the repressilator on a larger scale, using three distinct cell types that are chemically isolated from each other (i.e., not sharing medium) and are each equipped with genes that enable bioluminescence and photosensing. Cell type 1 is bioluminescent at a particular wavelength (e.g., blue). Cell type 2 produces yellow bioluminescence unless it perceives blue light. Cell type 3 produces bioluminescence at yet another wavelength (e.g., green) unless it senses yellow light. Green light represses cell type 1 blue bioluminescence. Thus, engineered cell-cell communication with light is possible, creating a "wireless" repressilator system.

References

• Photobiology of bacteria
• Differential activation of E. coli chemoreceptors by blue-light stimuli

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Directed Angiogenesis

NOTE: This project has been put on the back burner.

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Angiogenesis is crucial in many biological and disease processes. Usually stufied in the context of uncontrolled tumor growth, it is also a necessary element of wound healing and tissue engineering. A major problem with the application of engineered tissues is a lack of perfusion of the essential nutrients to keep the tissue alive, healthy, and properly integrated with the surrounding natural tissue. We would like to develop a natural phototaxis system in engineered bacteria which can be exploited to induce angiogenesis at targeted areas within the body. These living machines are programmed so that once they have arrived, they produce and secrete their payload (e.g., VEGF) and can be compared to "cellular dumptrucks".

References

Expression of biologically active isoforms of the tumor angiogenesis factor VEGF in Escherichia coli by Siemeister et al.

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