Effects of the Agrochemical Ethephon on Mimetic Systems of the Plasma Membrane

• Grant number: 23/14217-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2023
• End date: February 28, 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
• Associated research grant: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis, AP.TEM

Abstract

Contaminants from agriculture include agrochemicals such as pesticides, fertilizers, soil conditioners, and growth regulators for fruits and vegetables, among others. Among a wide range of products permitted in Brazil is ethephon (2-chloroethylphosphonic acid), a growth regulator that functions by releasing ethylene and is used to strengthen cereals, promote fruit and vegetable ripening, stimulate flowering, lateral branching, and reduce the height of ornamental plants. However, recent studies have indicated the harmful effects of ethephon on the male rat reproductive system. While in vivo studies demonstrate the effects of animal exposure to ethephon, the mechanism of action of this agrochemical in the body is poorly understood, and some hypotheses have been formulated, such as damage to cell membranes. In this context, we propose to investigate the interaction between ethephon and simple models of the lipid structure of the spermatozoa plasma membrane formed by mono and bilayer lipids. The monolayers will be formed by Langmuir films, and the bilayers by giant unilamellar vesicles (GUVs). The lipids used will be POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine), POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine), and sphingomyelin (SM) in a ratio of POPC/POPE/SM 2/2/1. These lipids, in addition to mimicking the fluid phase of mammalian cell plasma membranes, the 2/2/1 ratio was chosen because it closely matches the molar composition found in sperm membranes, structures highly sensitive to the exposure to agrochemicals in general.