University Honors

The use of herbicides has become pervasive in the agricultural industry as a method of controlling weeds and maximizing crop yield. Dichlorophenoxyacetic acid (2,4-D) is a selective herbicide which operates as a synthetic auxin, mimicking naturally occurring growth hormones in plants and inducing uncontrollable growth. This excessive growth is unsustainable and results in plant death, though the exact mode of action is not fully understood. 2,4-D residues present in the soil, air, and water can easily be adsorbed by humans and animals; this has shown to pose a serious health hazard by inducing free radical generation, lipid peroxidation, or apoptosis. We hypothesize that 2,4-D may undergo bioconjugation to key biomolecules through nucleophilic aromatic substitution (S NAr), which interferes with protein activity and disrupts key cellular processes. To assess the cytotoxic effects of 2,4-D, HEK293T cells were exposed to 1mM 2,4-D for thirty minutes, then proteins were extracted using a quantitative proteomics methodology utilizing the molecular chaperone DNAJB8. This molecule is part of the heat shock protein (Hsp40) family that binds to misfolded or non-native proteins. Following retrieval of DNAJB8 from cells, these bound protein samples were analyzed using a combination of gel electrophoresis, western blotting, silver staining, and mass spectrometry. We expected to see increased protein misfolding upon 2,4-D exposure: preliminary results indicate there is no significant correlation between 2,4-D exposure and protein misfolding. Further analysis suggests there may be a persistent bias present that the current experimental design does not account for and that a restructuring of experiments may be necessary.