Before we started our experiments, we obtained a violacein standard from Sigma-Aldrich,Item:V9389-1MG . We used this standard to measure the absorbance of violacein at varying concentrations, obtaining the standard curve shown below. Full wavelength scans were obtained, but as shown by previous iGEM teams (Cambridge 2009 ) the maximum absorbance of violacein is seen at 575nm and is reported here. During our experiments we worked with several different strains of E. coli, each containing plasmids with different violacein constructs:
Strain 1: pcdfDuet+VioABE
Strain 2:pcdfDuet+VioDC
Strain 3: pcdfDuet:VioABE+VioDC (full operon)
The details of growth and sample analysis can be found on our protocols page.