Title : Utilisation of optical spectroscopy and physical chemistry methods in studies of interaction between pesticide molecules and vital bio-macromolecules
Abstract:
Food production is expected to increase the quantity and quality crops, so pesticides are globally used for crop control. Question is whether using pesticides endangers the health of consumers. Comprehensive knowledge about pesticide side-effects on humans and animals includes a research of their influence on molecular level.
Studies of interactions between pesticides and vital bio-macromolecules on the molecular level represent an important step towards understanding pesticides´ toxicity and reducing their excessive using.
In this contribution we want to show how methods of optical spectroscopy and physical chemistry can be applied in the research concerning an influence of these problematic molecules on vital bio-macromolecules here represented DNA and transport proteins (human serum albumin, HSA). We have chosen two pesticide molecules as the examples to find basic binding characteristics between them and DNA, respectively HSA. Epoxiconazole (EPC) is a fungicide representing a conazole group of fungicides and a relatively new phenylpyrazole insecticide fipronil (FIP) which is extremely neurotoxic with good selectivity among insects and mammals. Optical methods such as absorption, fluorescence spectroscopies and optical dichroism associated with thermodynamic calculations, synchronous and 3D fluorescence spectra, competitive measurements and others have enabled to determine main binding characteristics of the pesticide molecules within the DNA and HSA, respectively, macromolecule structures.
The absorption and fluorescence spectra as well as a protein binding theory have utilized in finding of binding constants and mode of interaction between EPC and HSA and FIP and DNA, respectively. Moreover, the fluorescence spectra thermal dependence has used for the determination of a quenching mechanism given by Stern-Volmer equation at an incorporation of the fungicide molecule EPC within the HSA macromolecule.
Thermodynamic parameters such as melting temperature or enthalpy determined by thermal denaturation of FIP-DNA complex give an important fact about DNA stabilization or destabilization after the insecticide FIP interaction with DNA. Synchronous, 3D fluorescence, and CD spectra can be utilized for a finding of the studied macromolecules conformation changes as a consequence of pesticide molecules incorporation. Our contribution contains more possibilities of the utilization physical-chemical methods in the comprehensive characterization of interaction (or incorporation) of two chosen pesticides with vital-bio-macromolecules represented by DNA, and HSA.
