Team:Tec-Monterrey/Timeline

Development of a genetic frame for the creation of concentration-sensitive bacterial sensors

Bacterial reporters or whole-cell bacterial sensors have always been an area of application for genetic manipulation and synthetic biology. As a matter of fact, constructing a bioreporter bacteria that has the ability to detect toxic chemicals is considered one of the first accomplishments in the discipline of synthetic biology (van der Meer and Belkin, 2010). There are several advantages to using a bacterial bioreporter instead of a traditional physical or chemical sensor, for example, bacteria can offer the same specificity and sensitivity that traditional sensors offer, but they are much more portable and grow in inexpensive media. Furthermore, bacterial reporters also offer advantages over using other types of biosensors like enzymes and antibodies because they are living organisms and they are capable of analyzing samples through a process that involves many enzymes (Yagi, 2007)

The first bacterial reporters appeared 20 years ago (van der Meer and Belkin, 2010) although these early tests didn’t use genetically modified microorganisms. Further research and development in the areas of genetic engineering and synthetic biology have resulted in many more applications such as detection of contaminants (Willardson, et. Al., 1998) and sugar and amino acid availability in soils (Jaeger, et. Al., 1999). Even though the reporters have gotten more sophisticated and sensitive, we realized that there isn’t much mention of a single bacterial bioreporter capable of detecting different concentrations of a substance and reacting differently depending on the concentration.

We thought the use of synthetic biology as well as the BioBrick standard could help create a “genetic circuit” (van der Meer and Belkin, 2010) capable of detecting different concentrations of a substance and reacting in a different manner depending on the amount detected. In our initial research we realized that the iGEM British Columbia 2009 team decided to do something similar, so we used parts of their project as a base and integrated parts of other previous iGEM projects in order to propose a new genetic construction capable of detecting different amounts of a certain substance. We call these new types of sensors, “intelligent biosensors”, because they have the ability to react in different ways depending on their surroundings.

With our project we hope to continue with the previous efforts of other iGEM teams, and at the same time propose a new type of genetic circuit for achieving these functions. In the process we plan to develop BioBricks for two new families of phage activators as well as different BioBrick constructons that can make our system easy to adapt, so that the creation of these “intelligent biosensors” becomes just a matter of choosing the substance of interest and choosing the different reporters.

References

Jaeger, C. H., et. Al. (June 1999) Mapping of Sugar and Amino Acid Availability in Soil around Roots with Bacterial Sensors of Sucrose and Tryptophan. Applied and Environmental Microbiology, Vol. 65, No. 6, p. 2685 - 2690

Van der Meer, J. R. and Belkin, S. (July 2010) Where microbiology meets microengineering: design and applications of reporter bacteria. Nature Reviews Microbiology, Vol. 8, p. 511 - 522

Willardson, B. M., et. Al. (March 1998) Development and Testing of a Bacterial Biosensor for Toluene-Based Environmental Contaminants. Applied and Environmental Microbiology, Vol. 64, No. 3, p. 1006- 1012

Yagi, K. (2007) Applications of whole-cell bacterial sensors in biotechnology and environmental science. Applied Microbiology and Biotechnology, Vol. 73, p. 1251 - 1258