Silver/Chitosan Nanocomposites: Preparation and Characterization and Their Fungicidal Activity against Dairy Cattle Toxicosis Penicillium expansum

Abstract

This work aimed to evaluate the fungicide activity of chitosan-silver nanocomposites (Ag-Chit-NCs) against Penicillium expansum from feed samples. The physicochemical properties of nanocomposites were characterized by X-ray fluorescence analysis (XRF), small-angle X-ray scattering (SAXS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The morphological integrity of the nanohybrid was confirmed by electron transmission. By the data of RFA (X-ray fluorescent analysis), the contents of Ag in Ag-chitosan composite were 5.9 w/w%. The size distribution of the Ag nanoparticles incorporated in the chitosan matrix was investigated by SAXS. The main part of the size heterogeneity distribution in the chitosan matrix corresponds to the portion of small particles (3–4 nm). TEM analysis revealed a spherical morphology in the form of non-agglomerated caps, and 72% of the nanoparticles measured up to 4 nm. The minimum inhibitory concentration of NCs was evaluated in petri dishes. Three different concentrations were tested for antifungal activity against the mycotoxigenic P. expansum strain. Changes in the mycelium structure of P. expansum fungi by scanning electron microscopy (SEM) were observed to obtain information about the mode of action of Ag-Chit-NCs. It was shown that NC-Chit-NCs with sizes in the range from 4 to 10 nm have internalized sizes in cells, form agglomerates in the cytoplasm, and bind to cell organelles. Besides, their ability to influence protein and DNA fragmentation was examined in P. expansum. SDS-PAGE explains the apparent cellular protein response to the presence of various Ag-Chit-NCs. The intensity of P. expansum hyphal cell protein lines treated with Ag-Chit-NCs was very thin, indicating that high molecular weight proteins are largely prevented from entering the electrophoretic gel, which reflects cellular protein modification and possible damage caused by the binding of several protein fragments to Ag-Chit-NCs. The current results indicate that Ag-Chit-NCs <10 nm in size have significant antifungal activity against P. expansum, the causative agent of blue mold-contaminated dairy cattle feed.

Differential Antimycotic and Antioxidant Potentials of Chemically Synthesized Zinc-Based Nanoparticles Derived from Different Reducing/Complexing Agents against Pathogenic Fungi of Maize Crop

“…The genomic DNA fragmentation may be attributed to the physical and chemical properties of the NPs [ 55 ] including the size, concentration [ 56 , 57 ], chemistry [ 56 , 57 , 58 ], and surface functionalization [ 59 ]. Though within a fungal cell the predominant mechanism of degradation of the cellular DNA by ZnNPs is through formation of reactive oxygen species (ROS) which causes extensive DNA scissoring and fragmentation [ 7 ].…”

Copper-Chitosan Nanocomposite Hydrogels Against Aflatoxigenic Aspergillus flavus from Dairy Cattle Feed

“…Subsequently, the treatment of chitosan nanocomposites generates some biological reactions, such as oxidative stress-induced metabolic changes, which in turn affect the protein synthesis rate [ 56 ]. The toxicity of nanocomposites in fungal cells is due to severe metabolic changes, in particular protein synthesis, which resulted in a maximum protein reduction, as verified by the absence of the most important protein synthesis [ 57 ].…”

Chitosan in modern agriculture production

“…When chitosan is applied to a mutation suspension, its titer is reduced with chitosan. Electron microscopic analyses revealed that chitosan induced massive reforms in mutation particles and destabilised their stability (Alghuthaymi et al 2020).…”