Mycofabrication of bioactive silver nanoparticle: Photo catalysed synthesis and characterization to attest its augmented bio-efficacy

First identification of potato tuber rot caused by Penicillium solitum, its silver nanoparticles synthesis, characterization and use against harmful pathogens

Potato is one of the highly consumed vegetable crop grown in different regions across Pakistan that is affected by fungal diseases. The current research was conducted to identify fungal pathogen causing mold-like disease of potato in Khyber Pakhtunkhwa (KP), Pakistan. For molecular identification and characterization of the fungal disease; potato tuber samples were collected followed by culturing on potato dextrose agar (PDA). Based on morphological features, the pathogen was identified as a Penicillium species. This result was obtained in 45 different isolates from potato tubers. Molecular identification was done using β-tubulin primers and ITS5 sequencing of 13 different isolates that releveled 98% homology with BLAST (GenBank accession no. KX958076) as Penicillium solitum (GenBank accession nos. ON307317; ON307475 and ON310801). Phylogenetic tree was constructed that showed Penicillium solitum prevalence along with Penicillium polonicum and Penicillium citrinum on potato tubers. Based on this, Penicillium solitum based silver nanoparticles (Ag NPs) were synthesized and characterized using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX) and field emission scanning electron microscopy (FE SEM). UV-analysis showed a characteristic peak at 410 nm confirming synthesis of Penicillium solitum based Ag NPs. This was further confirmed by XRD followed by EDX and SEM that showed face cubic crystal structure with Ag as major constituent of 18 nm formed spherical Ag NPs. FTIR showed band stretching of O-H, N-O and C-H of biological origin. Similarly, Penicillium solitum based Ag NPs presented strong anti-bacterial and anti-fungal activity at 0.5 level of significance LSD. According to our knowledge, this is the first report of Penicillium solitum identification in Pakistan, its Ag NPs synthesis and characterization to be used against pathogens of agricultural significance.

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

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.

Biosustainable production of nanoparticles via mycogenesis for biotechnological applications: A critical review

The demand for the green synthesis of nanoparticles has gained prominence over the conventional chemical and physical syntheses, which often entails toxic chemicals, energy consumption and ultimately lead to negative environmental impact. In the green synthesis approach, naturally available bio-compounds found in plants and fungi can be effective and have been proven to be alternative reducing agents. Fungi or mushrooms are particularly interesting due to their high content of bioactive compounds, which can serve as excellent reducing agents in the synthesis of nanoparticles. Apart from the economic and environmental benefits, such as ease of availability, low synthesis/production cost, safe and no toxicity, the nanoparticles synthesized from this green method have unique physical and chemical properties. Stabilisation of the nanoparticles in an aqueous solution is exceedingly high, even after prolonged storage with unperturbed size uniformity. Biological properties were significantly improved with higher biocompatibility, anti-microbial, anti-oxidant and anti-cancer properties. These remarkable properties allow further exploration in their applications both in the medical and agricultural fields. This review aims to explore the mushroom-mediated biosynthesis of nanomaterials, specifically the mechanism and bio-compounds involved in the synthesis and their interactions for the stabilisation of nanoparticles. Various metal and non-metal nanoparticles have been discussed along with their synthesis techniques and parameters, making them ideal for specific industrial, agricultural, and medical applications. Only recent developments have been explored in this review.

Mycofabrication of AgONPs derived from Aspergillus terreus FC36AY1 and its potent antimicrobial, antioxidant, and anti-angiogenesis activities

BACKGROUND

There is an emergency need for the natural therapeutic agents to treat arious life threatening diseases such as cardio- vascular disease, Rheumatoid arthritis and cancer. Among these diseases, cancer is found to be the second life threatening disease; in this view the present study focused to synthesize the silver oxide nanoparticles (AgONPs) from endophytic fungus.

METHODS

The endophytic fungus was isolated from a medicinal tree Aegle marmelos (Vilva tree) and the potential strain was screened through antagonistic activity. The endophytic fungus was identified through microscopic (Lactophenol cotton blue staining and spore morphology in culture media) and Internal Transcribed Spacer (ITS) 1, ITS 4 and 18S rRNA amplification. The endophyte was cultured for the synthesis of AgONPs and the synthesized NPs were characterized through UV- Vis, FT- IR, EDX, XRD and SEM. The synthesized AgONPs were determined for antimicrobial, antioxidant and anti- angiogenic activity.

RESULTS

About 35 pigmented endophytic fungi were isolated, screened for antagonistic activity against 12 pathogens and antioxidant activity through DPPH radical scavenging assay; among the isolates, FC36AY1 explored the highest activity and the strain FC36AY1 was identified as Aspergillus terreus. The AgONPs were synthesized from the strain FC36AY1 and characterized for its confirmation, functional groups, nanostructures with unit cell dimensions, size and shape, presence of elements through UV-Vis spectrophotometry, FT-IR, XRD, SEM with EDX analysis. The myco-generated AgONPs manifested their antimicrobial and antioxidant properties with maximum activity at minimum concentration. Moreover, the inhibition of angiogenesis by the AgONPs in Hen's Egg Test on the Chorio-Allantoic Membrane analysis were tested on the eggs of Chittagong breed evinced at significant bioactivity least concentration at 0.1 µg/mL.

CONCLUSIONS

Thus, the results of this study revealed that the fungal mediated AgONPs can be exploited as potential in biomedical applications.

Copper oxide nanoparticles synthesized from an endophytic fungus Aspergillus terreus: Bioactivity and anti-cancer evaluations

The mycofabricated metal nanoparticles (NPs) plays a significant role in cancer therapeutics and imparts a strategy in medicine. The current investigation focused to synthesize the Copper Oxide Nanoparticles (CuONPs) using an endophytic fungus isolated from Aegle marmelosa medicinal tree located in Western Ghats, India. The endophytic fungus FCBY1 explored the highest antagonistic and antioxidant activities among the 16 pigmented endophytic fungal strains which were isolated from the collected samples. The fungus FCBY1 was identified for its morphological and molecular characteristics where the (Internal Transcribed Spacer) ITS 1, 5.8 ribosomal gene and ITS 2 were sequenced; and the organism FCBY1 is Aspergillus terreus. The endophyte was put through for the synthesis of CuONPs and the size and structure of the synthesized particles were characterized by Scanning Electron Microscope (SEM). The confirmation of the CuONPs was characterized by FT-IR, EDAX and XRD analyses. The CuONPs exhibited the maximized antibacterial and antifungal activities against the human clinical pathogens; moreover the particles also explicated the free radicals/ROS scavenging at minimum concentration, which was assessed through DPPH, nitric oxide radical scavenging assays, and reductive power ability. The anti-cancer activity of CuONPs on colon cancer cell lines (HT-29) was evaluated by MTT (IC₅₀: 22 μg/mL) and FACS analyses (32.11% cells gated in S phase of cell cycle). Angiogenesis inhibition in tumor cells was estimated through in vivo HET- CAM assessment and the highest concentration 60 μL tested inhibited the blood vessels at the percentage of 31.36% and 81.81%. The CuONPs explicated the anti-cancer activities in a concentration - dependent manner and the results of this investigation manifest the significant role of the CuONPs in cancer therapeutics.

Biological synthesis of silver nanoparticles using animal blood, their preventive efficiency of bacterial species, and ecotoxicity in common carp fish

Possible high biodeterioration of the microorganisms due to their metabolic pathway and activities on stone materials causes solemn problems in cultural heritage. Different kinds of laboratory-scale methods have been used for the reduction of microbial growth, that is, chemical, mechanical, and physical, which are cost-effective and not ecofriendly. In the current study, an ecofriendly approach utilizing silver nanoparticles were synthesized using sheep blood serum. Transmission electron microscopy results have confirmed the spherical and well dispersed silver nanoparticles with an average size of 32.49 nm, while energy dispersive X-ray has shown the abundance of silver nanoparticles. The efficiency against bacterial species was verified through laboratory-scale testing. The strong antibacterial activity was confirmed when B-AgNPs was tested against different bacterial species isolated from the Beishiku Cave Temple. The largest zone of inhibition was measured 26.48 ± 0.14 mm against Sphingomonas sp. while the smallest zone of inhibition measured was 9.70 ± 0.27 mm against Massilia sp. Moreover, these ecofriendly B-AgNPs were tested for daily based dose in different concentrations (0.03, 0.06, and 0.09 mg/L) against common carp fish for a long exposure (20 days) and 6.5% fatality was found. The highest lethal concentration (LC₅₀ ) for fish (0.61 ± 0.09 mg/L). No doubt, the laboratory scale applications have revealed the best results with minute toxicity in fish. Therefore, sheep serum should be continued to synthesize silver nanoparticles on a large scale. A strict monitoring system should be developed for the synthesis and application of AgNPs.