Biogenic Silver Nanoparticles Produced by Soil Rare Actinomycetes and Their Significant Effect on Aspergillus-derived mycotoxins

Abstract

The current investigation addressed the green synthesis of silver nanoparticles (AgNPs) using newly isolated silver-resistant rare actinomycetes, Glutamicibacter nicotianae SNPRA1 and Leucobacter aridicollis SNPRA2, and investigated their impact on the mycotoxigenic fungi Aspergillus flavus ATCC 11498 and Aspergillus ochraceus ATCC 60532. The formation of AgNPs was evidenced by the reaction’s color change to brownish and the appearance of the characteristic surface plasmon resonance. The transmission electron microscopy of biogenic AgNPs produced by G. nicotianae SNPRA1 and L. aridicollis SNPRA2 (designated Gn-AgNPs and La-AgNPs, respectively) revealed the generation of monodispersed spherical nanoparticles with average sizes of 8.48 ± 1.72 nm and 9.67 ± 2.64 nm, respectively. Furthermore, the XRD patterns reflected their crystallinity and the FTIR spectra demonstrated the presence of proteins as capping agents. Both bioinspired AgNPs exhibited a remarkable inhibitory effect on the conidial germination of the investigated mycotoxigenic fungi. The bioinspired AgNPs caused an increase in DNA and protein leakage, suggesting the disruption of membrane permeability and integrity. Interestingly, the biogenic AgNPs completely inhibited the production of total aflatoxins and ochratoxin A at concentrations less than 8 μg/mL. At the same time, cytotoxicity investigations revealed the low toxicity of the biogenic AgNPs against the human skin fibroblast (HSF) cell line. Both biogenic AgNPs exhibited feasible biocompatibility with HSF cells at concentrations up to 10 μg/mL and their IC50 values were 31.78 and 25.83 μg/mL for Gn-AgNPs and La-AgNPs, respectively. The present work sheds light on the antifungal prospect of the biogenic AgNPs produced by rare actinomycetes against mycotoxigenic fungi as promising candidates to combat mycotoxin formation in food chains at nontoxic doses.

Malignance‐restriction activity exhibited by bioactive compounds of selected actinobacteria as silver nanoparticles against A549 lung cancer cell lines

“…Singh et al 42 found that 15 isolates have antibacterial activity against Gram‐positive bacteria and MDR bacteria by the perpendicular streak method. Ghany et al, 38 discovered that actinomycete‐mediated silver nanoparticles could disrupts the life cycle of mycotoxigenic fungi, inhibiting conidial germination and compromising membrane integrity, leading to reduced aflatoxin and ochratoxin A production. The metabolite production by submerged state fermentation techniques shows good results in antimicrobial activity 43 against pathogenic bacteria.…”

“…The isolates LA2(R) M. proteolyticum and LA2(O) S. rochei were inoculated in a 500 mL flask containing 100 mL of ISP‐2 medium (g/L): yeast extract, 4.0; malt extract, 10.0; dextrose, 4.0; agar, 20.0; distilled water, 1000 mL; and pH, 7.3. The flasks with inoculated strains were incubated for 5–7 days at 200 rpm in a rotary shaker 38 . The cultures were centrifuged at 10,000 rpm after the growth, and its supernatant was used for future experimentations 39 …”

Exploring the Potential of Halotolerant Actinomycetes from Rann of Kutch, India: A Study on the Synthesis, Characterization, and Biomedical Applications of Silver Nanoparticles

“…Recently, Ghany et al synthesized monodispersed spherical AgNPs having an average size of 8.48 ± 1.72 nm and 9.67 ± 2.64 nm from actinomycetes Glutamicibacter nicotianae SNPRA1 and Leucobacter aridicollis SNPRA2, respectively [ 90 ]. Further, Nayka and their team also reported the formation of spherical and polydisperse AgNPs of size 32.40 nm from Streptomyces sp.…”