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Open Access Thesis

Keywords

Metolachlor--Physiological effect; Liver--Growth; Academic theses;

Abstract

Metolachlor is one of the most commonly used herbicides in the United States of America. Numerous studies have shown that exposure to this herbicide results in decreased cell proliferation, growth and reproductive ability in different organisms. However, pervious studies used high concentrations of metolachlor to see molecular effects. In the study presented here, we investigated the effects of metolachlor on human cells. Previous cell proliferation analysis from our laboratory has shown that metolachlor is capable of significantly inhibiting the growth of normal human fibroblasts and HepG2 cells at 1.6 parts per billion (ppb) and 50 ppb. We assessed cellular effects after exposure to this herbicide including cell proliferation assay using the CyQUANT assay and CellTrace™ CFSE dye, transcript expression of cell cycle proteins, (cyclins) A, B, D1, and E using RT-PCR, and alteration of cell cycle progression using flow cytometry. Our results showed that exposure to 50 ppb metolachlor for 72 h significantly inhibited cell growth. Exposure to 500 ppb metolachlor for 48 h also caused a significant decrease in cell proliferation rate. Exposure to 300 and 500 ppb metolachlor for 12 and 24 h also resulted in a significant decrease in abundance of the cyclin A transcripts, suggesting the herbicide may affect progression through the S-phase of the cell cycle and entrance into 02. However, no significant change was observed in transcript expression for cyclins B, D1, and E. Flow cytometry analysis showed that metolachlor exposure for 24 h resulted in an accumulation of cells in S-phase and decreased amounts in G2at 48 and 72 h, suggesting an arrest of cells at he S-phase.

Year of Submission

2010

Degree Name

Master of Science

Department

Department of Biology

First Advisor

Kavita R. Dhanwada

Second Advisor

Tilahun Abebe

Third Advisor

David J. McClenahan

Comments

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Date Original

2010

Object Description

1 PDF file (87 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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