Biosynthesis of Novel Tellurium Nanorods by Gayadomonas sp. TNPM15 Isolated from Mangrove Sediments and Assessment of Their Impact on Spore Germination and Ultrastructure of Phytopathogenic Fungi

Abstract

The biosynthesis of nanoparticles using green technology is emerging as a cost-efficient, eco-friendly and risk-free strategy in nanotechnology. Recently, tellurium nanoparticles (TeNPs) have attracted growing attention due to their unique properties in biomedicine, electronics, and other industrial applications. The current investigation addresses the green synthesis of TeNPs using a newly isolated mangrove-associated bacterium, Gayadomonas sp. TNPM15, and their impact on the phytopathogenic fungi Fusarium oxysporum and Alternaria alternata. The biogenic TeNPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR). The results of TEM revealed the intracellular biosynthesis of rod-shaped nanostructures with a diameter range from 15 to 23 nm and different lengths reaching up to 243 nm. Furthermore, the successful formation of tellurium nanorods was verified by SEM-EDX, and the XRD pattern revealed their crystallinity. In addition, the FTIR spectrum provided evidence for the presence of proteinaceous capping agents. The bioinspired TeNPs exhibited obvious inhibitory effect on the spores of both investigated phytopathogens accomplished with prominent ultrastructure alternations, as evidenced by TEM observations. The biogenic TeNPs impeded spore germination of F. oxysporum and A. alternata completely at 48.1 and 27.6 µg/mL, respectively. Furthermore, an increase in DNA and protein leakage was observed upon exposure of fungal spores to the biogenic TeNPs, indicating the disruption of membrane permeability and integrity. Besides their potent influence on fungal spores, the biogenic TeNPs demonstrated remarkable inhibitory effects on the production of various plant cell wall-degrading enzymes. Moreover, the cytotoxicity investigations revealed the biocompatibility of the as-prepared biogenic TeNPs and their low toxicity against the human skin fibroblast (HSF) cell line. The biogenic TeNPs showed no significant cytotoxic effect towards HSF cells at concentrations up to 80 μg/mL, with a half-maximal inhibitory concentration (IC50) value of 125 μg/mL. The present work spotlights the antifungal potential of the biogenic TeNPs produced by marine bacterium against phytopathogenic fungi as a promising candidate to combat fungal infections.

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 …”

Metal Nanomaterials and Hydrolytic Enzyme-Based Formulations for Improved Antifungal Activity

“…Thus, many authors did not try to. However, to date, many such (nano)formulations have been developed using microalgal [10,47], bacterial [48,49], fungal [50], plant [51,52], and other isolates. A slightly more accurate method applies, at least, partially purified proteins [53,54] and pure polypeptides [55] for the green synthesis of NPs.…”

“…Thus, different metal NPs can be synthesized via the green route (Table 2 [10,[47][48][49][50][51][52][53][54][55]). For example, the application of Ag led to the profound antibacterial activity of obtained formulations [48,52], thus giving additional functionality and opening an opportunity to treat multi-microbial associations.…”

“…Due to their small size, NPs can be adsorbed on the surface of spores and visualized there [49]. After that, physical damage and/or hindrances to the penetration of activating factors, as well as chemical modification(s) of the spore envelope, outer receptors, and transport channels are possible.…”