Toxic Effects of Chlorpyrifos Exposure on Development of Caenorhabditits Elegans
Chlorpyrifos is a commonly utilized organophosphate pesticide, and as recently as 2007, was the most commonly used insecticide within the United States. Its ubiquity is concerning given its potential to cause developmental issues among younger organisms and its association with neurodegenerative conditions like Parkinson's Disease. Pathways by which these issues arise are unclear since these effects can occur in absence of acetylcholinesterase inhibition. To this end, experiments utilizing Caenorhabditis elegans as a model were performed. The organism is useful as a model for several reasons, of which are its rapid maturation, its ease of maintenance, and its transparent body that allows examination of intact bodily systems. C. elegans also possesses a fully characterized neuronal lineage with a complete neural wiring diagram, and several conserved neurotransmitter systems. The primary purpose of this research was to determine if chlorpyrifos would have an impact on the behavior, morphology, or nervous system of C. elegans at selected concentrations, ranging from low levels considered generally safe to high levels with noted lethal impacts on C. elegans. Populations were grown on media containing chlorpyrifos during larval stages and then transferred to media without chlorpyrifos for 24 hours to separate developmental impacts of chlorpyrifos from its active effects. Analysis of chlorpyrifos-exposed C. elegans produced some notable results. Video analysis revealed that worms exposed to high chlorpyrifos concentrations had decrease in body length and width. Exposure to high concentrations of chlorpyrifos showed increasing germline apoptosis over control groups. Pharyngeal pumping assays showed paralysis at high concentrations, and no paralysis at low concentrations. Finally, an assessment of C. elegans dopaminergic neurons indicated neuron loss at both low and high developmental exposure. These results show a deleterious impact at high concentrations, with worms showing developmental delays and stunted growth. The compound seems capable of impacting bodily systems outside of the nervous system, as seen in the germline apoptosis assay. Concentrations tested have the desired impacts, with high chlorpyrifos exposure groups showing paralysis and low dose groups showing no paralysis. Most interestingly, the pesticide appears to cause dopaminergic neuron degradation at low concentrations, providing a link between chlorpyrifos and neurodegenerative conditions.
Adams, Kevin. (December 2016). Toxic Effects of Chlorpyrifos Exposure on Development of Caenorhabditits Elegans (Master's Thesis, East Carolina University). Retrieved from the Scholarship. (http://hdl.handle.net/10342/6047.)
Adams, Kevin. Toxic Effects of Chlorpyrifos Exposure on Development of Caenorhabditits Elegans. Master's Thesis. East Carolina University, December 2016. The Scholarship. http://hdl.handle.net/10342/6047. April 22, 2019.
Adams, Kevin, “Toxic Effects of Chlorpyrifos Exposure on Development of Caenorhabditits Elegans” (Master's Thesis., East Carolina University, December 2016).
Adams, Kevin. Toxic Effects of Chlorpyrifos Exposure on Development of Caenorhabditits Elegans [Master's Thesis]. Greenville, NC: East Carolina University; December 2016.
East Carolina University