Team:USP-Brazil/Improve

Wiki - iGEM Brazil

Applications

In our project, for the measurement of our quorum sensing response, we used a system based on a reporter fluorescent protein (EYFP) and a control one (ECFP), constitutively expressed, that would be subject to the same extrinsic variation as the reporter gene, but would not respond to our tested stimuli, allowing us to use this CFP measurement to normalize YFP. This gives us the possibility of a much more reproducible result, less dependant on growth media and cell density (a rather unreliable parameter to measure) at the time of each measurement.

Something else we did to raise the precision of our measurements was not using LB for measuring in the plate reader, as it had high autofluorescence and commonly exibited fluorescence higher than our tests at low CFP values. Also, LB may change its color depending on how old it is and other environmental interactions. By centrifuging the cells for each sample and resuspending them in molecular grade H2O, we had a blank with much lesser autofluorescence and with less variance between measurements.