Human aryl hydrocarbon receptor (AhR) signaling responses to MC252 oil fractions in YCM3 yeast

These are a series of comparative responses of human aryl hydrocarbon receptor (AhR) signaling to MC252 oil fractions. The material was fractionated oil by D. Pangeni and E. Overton, collaborators at LSU using a silica gel chromatography method with hexane as the starting solvent and mixing with dichlormethane up to 50% final volume to resolve the aromatic hydrocarbons. 50 ul aliquots were dried and sent to the Miller lab for human AhR signaling and other toxicity testing. YCM3 yeast was exposed to varying dilutions of the 27 oil fractions and assessed for AhR signaling with a lacZ reporter assay. The greater the dilution that retains signing ability, the more potent and/or abundant the PAH ligand(s) are in the sample. Two strong peaks of activity are seen for fractions 17-18 and 20-24. These fractions contain different PAHs indicated in the chart at the end of the data. Compounds of interest in the fractions include methyl-substituted chrysenes.