Pesticide-induced oxidative stress and its effects on cell growth, feeding, and motility in Tetrahymena thermophila
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Authors
Doyle, Sophia
Nessan, Erica
Date of Issue
2023-04-28
Type
Presentation
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Abstract
In the United States alone, an estimated 1 billion pounds of conventional pesticides, including insecticides, herbicides, and fungicides, are used annually. This widespread use is occurring with little regard to research showing that pesticides cause oxidative stress in humans by disrupting the balance between reactive oxygen species (ROS) and antioxidant mechanisms. The resulting ROS accumulation can lead to double-stranded DNA breaks, with several studies linking this damage to aging-related diseases. The purpose of this research was to investigate the effect of pesticides on oxidative stress and related behaviors in the model organism, Tetrahymena thermophila. It was hypothesized that pesticide exposure would alter expression of the MXR1 gene, which plays a role in the cellular response to oxidative stress, as well as impact cell growth, phagocytosis, and motility. To test this hypothesis, T. thermophila cultures were assigned to a control or treatment group; the treatment group cultures were exposed to 0.5% Roundup, Raid, or Copper Fungicide for 48 hours. During the 48-hour incubation period, cell growth and feeding were measured using a growth assay and an India ink feeding assay, respectively. At the end of the 48-hour incubation, T. thermophila movement was characterized using a cell motility assay followed by RNA extraction and RT-qPCR to measure the expression of MXR1. Given the known impact of pesticides on the accumulation of reactive oxygen species, it was predicted that T. thermophila cultures exposed to pesticides would exhibit increased MXR1 expression and subsequent decreases in growth rate, feeding activity, and cell motility.