Reporter

Part:BBa_K1073022:Experience

Designed by: iGEM Team Braunschweig 2013   Group: iGEM13_Braunschweig   (2013-09-17)


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Applications of BBa_K1073022

The iGEM Team Braunschweig 2013 used this device as a reporter to distinguish two different strains when cultivated in a mixed culture.
When eforRed is expressed, the colonies on agar plates as well as the liquid culture exhibit a bright pink color.


Part Sequence Quality

The Tech Museum, May 2014: This part's real sequence may end with two stop codons, TAATAA. This is not listed in the original source part's sequence or in this part's sequence, but sequencing from the registry indicates it may be present. Beware.

User Reviews

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iGEM Team Braunschweig 2013

When expressed, the chromoprotein eforRed exhibits a distinct pink color. In order to avoid absorption by the chomoprotein during OD measurement of a bacterial culture, the absorption and emission spectra were measured. An optimal wavelength for spectral optical density measurement was determined to be at 520nm.

BSAbsorption-eforRed.jpg

iGEM Team Braunschweig 2013: Absorption spectrum of chromoprotein eforRed in the wavelength range 400-800 nm.

Absorption maximum of eforRed: 534 nm

BS2013Emission eforRed.jpg

iGEM Team Braunschweig 2013: Emission spectrum of chromoprotein eforRed. The chromoprotein does show significant emission and can be detected by its fluorescence.

Emission maximum of eforRed: 605 nm


Fluorescence.JPG

iGEM Team Braunschweig 2013: Supernatant after cell disruption containing chromoproteins of eforRed and amilGFP (BBa_K1073024). Both chromoproteins fluoresce when excited by UV-light.

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iGEM Team Pasteur Paris 2019

To further characterize this biobrick, we decided to focus on the fluorescence expression of eforRed in E. coli.

Fluorescence microscopy

This experiment was performed using an RFP filter. Samples were analyzed after 30 hours of incubation and compared to a non-transformed E. coli strain.


T--Pasteur Paris--Fluorescence microscopy eforRed 1.png


We can clearly see that BBa_K1073022 allows the expression of red fluorescence in E. coli after several hours of incubation.

However, when we merged brightfield and mRFP images, we observed that the fluorescence is not expressed by all of the bacteria.


T--Pasteur Paris--Fluorescence microscopy eforRed 2.png


Flow cytometry

In addition of fluorescence microscopy, we performed flow cytometry in order to test the efficiency of transformation and the stability of the expression of eforRed over time.


T--Pasteur Paris--Flow cytometry.jpg


Less than 50% of bacteria expressed the red fluorescence after 2 hours of incubation, and this percentage decreases over time.

This low percentage of expression could be explained by a poor transformation efficiency. When the selective pressure was removed, the bacteria continued to lose expression of the chromoprotein as wild type bacteria out-competed those with the plasmid.

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