Team:William and Mary/Interlab



We participated in the Interlab Measurement Study using Flow Cytometry analysis on a FACS (Fluorescence-Activated Cell Sorter) machine following the protocol provided by iGEM. Our results are presented here:

In addition to participating in the Interlab Study, we also wanted to determine if there would be a noticeable difference between measurements taken at Midlog and measurements taken on those same samples at Saturation.

We noticed that although there were differences between the midlog and saturation measurements, they were not very drastic across the different devices when looking at bulk population-level mean measurements, with the exception of the negative control.

However, because we measured the devices with flow cytometry, we were additionally able to assess the changes in population heterogeneity which occur with between midlog phase and saturation phase. We found that the midlog populations tended to be more unimodal than the saturation populations.

Fig. 3: Representative single-cell histograms of absolute fluorescence levels for the same sample at midlog phase vs. at saturation phase

A possible explanation for this phenomenon is that the antibiotic selection for the reporter construct may weaken over time, allowing subpopulations of cells to develop which have varying metabolic emphases on the reporter construct.

All of the FACS plots from our Interlab study are available upon request.