Team:CIDEB-UANL Mexico/project resistance

Because our project is a biofilter which allows to remove salt from water, the bacteria needs to survive to extreme environmental conditions which normally it can’t do. We need E. coli to survive a high salinity environment to allow it to capture sodium ions and to remove the salt concentration of the water. In order to accomplish our project goal, we have to change E. coli metabolism and make it stronger, more resistant and more efficient than in normal E. coli bacteria.

Last discoveries show irrE as a protein capable of change the E. coli metabolism, and giving it the ability to survive to bigger temperatures, bigger UV rays radiation and bigger salt concentration (UCL, 2012).

Description

What does irrE do?

The protein irrE originates from Deinococcus radiodurans, and initially, this gene provides resistance to radiation. But when transformed in E. coli, it protects it against salt, oxidative and thermal shock. (UCL, 2012) Also, different experiments from different iGEM teams, support the idea of the bigger salt resistance in E. coli with this biobrick.

How it works?

irrE has been demonstrated to up regulate transcription of recA and pprA - genes which encode Recombines A and Radiation Inducible Protein. With respect to salt tolerance, irrE up regulates the production of several stress responsive proteins, protein kinases, metabolic proteins, and detoxification proteins. It also down regulates glycerol degradation. With this global regulatory effect, E. coli becomes more salt tolerant (UCL, 2012).

Device

How it is composed?

Initially, IrrE and L2+AIDA, protein for binding silica (Union module), were joined together in only one circuit, but we needed to separate them because L2+AIDA has not been proved yet and it could affect the correct production of IrrE (see image 3).

Parts of the Module

Justifications

The resistance module is very important in our project because it allows the corect function of the bio-filter. Because the objective is to remove the sodium ions from the water. E. CARU, at the beggining of the process, the bacteria will be surrounded by salt molecules which normally E. coli could not support.

IrrE gives resistance to the high salt concentration of the water, allowing the Nhas gene to function and capture the sodium ions.

Another important aspect in the usage of the IrrE gene, is because the promotor in the Capture module is activated with UV rays at 360 wv, intensity that can cause mutations to the bacterium. IrrE protects E. coli from UV rays and allows the bacteria to their work.

Other teams that used IRRE

UCL 2012: They propose to confer salt tolerance on E. coli by linking the salt tolerance gene encoding the protein irrE (BBa_K729001) to a constitutive promoter (BBa_J23119).

Project Zoom In

Bibliography/References