Construction and Application of EGCG-Loaded Lysozyme/Pectin Nanoparticles for Enhancing the Resistance of Nematodes to Heat and Oxidation Stresses

Abstract

Novel nanoparticles (NPs) were constructed with lysozyme (LY) and pectin (Ps) through self-assembly, which were used as a carrier to encapsulate epigallocatechin-3-gallate (EGCG). The binding of EGCG and LY is a static quenching process. Hydrogen bonds might play a major role in the formation of NPs, which has also been verified by a lower binding constant of EGCG with LY/Ps NPs. Meanwhile, EGCG could lead to conformational and microenvironmental changes of LY, resulting in more folding of LY secondary structures. In addition, attaching Ps to LY might inhibit LY aggregation induced by addition of free EGCG. At the LY/Ps mass ratio of 1:1, the constructed LY/Ps NPs had a high EGCG-loading capacity without a significant change in mean particle size, thus, our NPs could be used as an effective nanocarrier for loading EGCG. In vivo, compared with free EGCG, EGCG loaded onto LY/Ps NPs significantly increased Caenorhabditis elegans’ (C. elegans) resistance to heat stress and oxidative injury and prolonged their lifespan. This study provides theoretical basis and reference for constructing nanoactive substance carriers so as to improve the resistance of organisms to heat stress and oxidative damage and to increase their survival rate and extend their lifespan under environment stresses.

Interaction investigation and phase transition of carrageenan/lysozyme complex system

“…Different Ly/CRG complex ratios (1:7, 1:5, 1:3, 1:2) were prepared at room temperature, while same concentrations of Ly solution were used as controls. Using a fluorescence spectrometer (Zhang et al, 2021b), adjusted to a fixed excitation wavelength λex of 280 nm, excitation and emission slit width were 2.5 nm and 2.5 nm, voltage 400 V, spectral scanning speed of 60 nm/ min, set the scan range 290-500 nm, fluorescence spectra were obtained in different proportions. Furthermore, Ly and CRG were prepared in different ratios (2:1, 1:2, 1:3, 1:7), the system temperature was adjusted and incubated at different conditions (25 °C, 40 °C, 60 °C, 80 °C) and the fluorescence spectra were then measured.…”

“…The interaction between proteins and polysaccharides has attracted a lot of attention, they can be used as emulsion stabilizers, fat substitutes and encapsulation of nutrients (Ashaolu & Zhao, 2020;Zhang et al, 2021b). The different composite ratios of proteins and polysaccharides, the pH of the solution, ionic strength and temperature are the main factors affecting the electrostatic interaction between the composite system.…”