COMBINED EFFECTS OF PESTICIDES ON TERNARY LIPID MONOLAYERS AS MIMETIC SYSTEMS OF CELL MEMBRANE

Published in 12/12/2023 - ISBN: 978-65-272-0088-8

Paper Title
COMBINED EFFECTS OF PESTICIDES ON TERNARY LIPID MONOLAYERS AS MIMETIC SYSTEMS OF CELL MEMBRANE
Authors
  • Luis F.C. Morato (DR), FCT-UNESP
  • Gilia Cristine Marques Ruiz
  • Wallance Moreira Pazin
  • Osvaldo de Oliveira Junior
  • Carlos José Leopoldo Constantino
Modality
Pôster
Subject area
Biossensores / Biomoléculas
Publishing Date
12/12/2023
Country of Publishing
Brasil
Language of Publishing
Inglês
Paper Page
https://www.even3.com.br/anais/workshop-do-ineo-2023/613012-combined-effects-of-pesticides-on-ternary-lipid-monolayers-as-mimetic-systems-of-cell-membrane
ISBN
978-65-272-0088-8
Keywords
Langmuir films, lipids, pesticides
Summary
Emerging pollutants have been targeted in recent researches due their potential risks to human health and the environment. Among these pollutants are the pesticides, which are necessary to combat pests mainly in large-scale crops. However, the management, application and irregular disposal of these products can lead to environmental contamination, favoring their consumption through food and water. An important condition to consider is the mixture of various pollutants, which can lead to the calling "cocktail effect", resulting in combined effects of multiple products in human health. In order to investigate such effects, we used a mimetic system of the cell membrane (organelle responsible by the cell integrity) based on lipid monolayers (Langmuir Films) composed of a mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), cholesterol and sphingomyelin (SM) in the proportion found in the mammalian membranes (ternary monolayer - 70/20/10 mol %, respectively). The pesticides used in this work were acephate, an insecticide from the organophosphorus family that can cause negative effects on the human neurological system, and diuron, an urea-class herbicide that has carcinogenic potential, especially in the bladder region. The Langmuir monolayers were characterized by p-A isotherms, PM-IRRAS (Polarization Modulation – Infrared Reflection – Adsorption Spectroscopy) and Brewster Angle Microscopy (BAM) in the following system: ternary monolayer in the absence and presence of acephate, diuron and their mixture (all subphase concentrations equal to 0.25 x 10-5 M). The p-A isotherms of the ternary mixture showed no differences in the displacements caused by either the individual pesticides or their mixture at the subphase. The compressional modulus decreased in the presence of both pesticides and their mixture, although the monolayer remained in the Liquid Condensed phase (LC) for the three different subphases. Regarding PM-IRRAS spectra, the individual pesticides and their mixture affected the phosphate group present on the head regions of POPC and SM, the amide-I group present only in the SM molecule, and the hydrocarbon chain of the lipids. In the presence of acephate, the relative intensity (RI) of the phosphate group, PO2- (considering the bands of symmetric and the asymmetric stretching) decreased from 0.39 (ultrapure water subphase) to 0.21 (pesticide subphase), while the amide-I band shifted to higher wavenumbers. However, in the presence of diuron, the PO2- RI increased to 0.58, while a similar effect to that observed at acephate subphase is noticed in the amide-I band. The spectrum of the ternary monolayer in the presence of the pesticide cocktail showed a similar effect on the PO2- group bands observed with acephate (the RI decreases to a value of 0.28), while the amide-I group band revealed a different effect compared to the subphases of the separated pesticide: the band shifted to lower wavenumbers (from 1662 to 1656 cm 1). Regarding the hydrophilic lipid region (2800-3000 cm-1), the RI in reference to the symmetric and asymmetric stretching of the CH2 group increased from 0.20 (ultrapure water subphase) to 0.34 and 0.38 at the acephate and diuron subphases, respectively, indicating a decrease in the ordering of the hydrocarbon chains. In the presence of the cocktail, the RI reached the value of 0.52, indicating that the mixture of pesticides promotes a higher disorder compared to the separated pollutants. The morphology of the ternary monolayer showed a less compact film in the presence of the cocktail, which is in accordance with the compressional modulus of this system. In summary, although p-A isotherms did not reveal differences between the effects of individual and combined pesticides, with the PM-IRRAS analyzes was possible to determine that the pesticide cocktail promotes the higher interaction with the amide-I and hydrocarbon chain groups of the monolayer. Acknowledgments: CAPES, FAPESP, CNPq, INEO
Title of the Event
Workshop do INEO 2023
City of the Event
Nazaré Paulista
Title of the Proceedings of the event
Anais do Workshop INEO 2023
Name of the Publisher
Even3
Means of Dissemination
Meio Digital
DOI
LinkGet DOI

How to cite

FCT-UNESP, Luis F.C. Morato (DR), et al.. COMBINED EFFECTS OF PESTICIDES ON TERNARY LIPID MONOLAYERS AS MIMETIC SYSTEMS OF CELL MEMBRANE.. In: Anais do workshop INEO 2023. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2023. Available in: https//www.even3.com.br/anais/workshop-do-ineo-2023/613012-COMBINED-EFFECTS-OF-PESTICIDES-ON-TERNARY-LIPID-MONOLAYERS-AS-MIMETIC-SYSTEMS-OF-CELL-MEMBRANE. Access in: 15/06/2024

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