Effects of the agrochemical ethephon on mimetic systems of the plasma membrane

• Grant number: 25/02754-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: December 31, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Carlos José Leopoldo Constantino
• Grantee: Maitê Renata Valério Caldeira
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

The growing global concern about pollution generated by agriculture, especially agrochemicals, has driven studies on their impacts on human health and the environment. Ethephon (2-chloroethylphosphonic acid; ETF), an organophosphate pesticide used to regulate plant growth through the release of ethylene, is one such concerning compound and has been associated with various toxic effects, including mutagenicity and teratogenicity. Recent in vivo studies have indicated that exposure to ETF can impair male rat fertility by reducing hormone levels, affecting testicular tissue integrity, and decreasing sperm count in these animals. One of the most effective methods for assessing the health risks of substances is analyzing their interaction with the plasma membrane, which serves as the first point of contact with cells. The plasma membrane is predominantly composed of different types of lipids. However, these systems are highly complex and contain various other components. Therefore, the use of mimetic models is extensively employed, as disturbances in these systems are good indicators of the actual action of external agents in biological processes involving membranes. This project proposes to analyze these interactions through the formation and characterization of mimetic systems based on lipid bilayers organized into vesicles. For this purpose, giant unilamellar vesicles (GUVs) will be formed using the lipids POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine), POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine), and SM, as well as large unilamellar vesicles (LUVs) and small unilamellar vesicles (SUVs) composed of a ternary mixture of these lipids in a 2/2/1 ratio. This composition aims to ensure that the mimetic system maintains the fluid phase characteristic of mammalian cell plasma membranes and a mass composition similar to that found in sperm membranes. The study seeks to build upon the findings of ongoing research (IC/BCO FAPESP 2023/14271-3) and further contribute to the understanding of ETF's effects on the plasma membrane while avoiding the complexity of in vivo systems. The IC/BCO FAPESP 2023/14271-3 fellowship began on 11/01/2023 as a budget allocation under the Thematic Project 2018/22214-6, which will conclude on 02/28/2025. Consequently, the IC/BCO FAPESP 2023/14271-3 fellowship received its last renewal for only four months, coinciding with the end of the Thematic Project. Thus, this request, which is technically a renewal, must be submitted through the regular procedure as if it were a new fellowship.