Biosynthesis and characterization of zinc oxide nanoparticles from an estuarine-associated actinobacterium Streptomyces spp. and its biotherapeutic applications

Anticancer, antioxidant and antibacterial potential of L-Glutaminase (Streptomyces roseolus strain ZKB1) capped silver and zinc oxide nanoparticles and its molecular characterization

The current investigation reports anti-cancer, antioxidant and antibacterial potential of L-Glutaminase (Streptomyces roseolus strain ZKB1) and L-Glutaminase capped nanoparticles. The highest L-Glutaminase production of 9.57 U/mL was achieved on the 4th day of fermentation when L-Glutamine was used as the sole carbon and nitrogen source. Enhanced recycling stability was observed after 6 cycles using L-Glutaminase immobilized in 3% agar and agarose matrices. Free and immobilized L- Glutaminase showed Km of 13.89 ± 0.8 and 7.13 ± 0.3 mM and Vmax of 18.40 ± 1.5 and 24.21 ± 1.7 U/mg respectively. L- Glutaminase capped silver (AgNP) and zinc oxide (ZnONP) nanoparticles were synthesized and structurally characterized using UV visible spectroscopy, FTIR, SEM-EDS, XRD and AFM. L- Glutaminase capped AgNP and ZnONP exhibited good thermal stability with five and three stages weight loss pattern respectively based on TGA. L-Glutaminase capped AgNP exhibited highest inhibitory activity against B. subtilis (45 ± 0.5 mm) and E. coli (33 ± 0.8 mm) whereas, L-Glutaminase capped ZnONP demonstrated highest inhibition against E. coli (30 ± 0.3 mm) and B. cereus (25 ± 0.5 mm). Increased nanoparticles concentration exhibited increased inhibitory potential as compared to wild L-Glutaminase and lowest MIC of 0.09 µg/mL was exhibited against B. cereus. L-Glutaminase capped nanoparticles demonstrated significant antioxidant properties through in-vitro ABTS and DPPH radical scavenging assays in a dosage-dependent manner. L-Glutaminase and capped AgNP and ZnONP, demonstrated pronounced cell cytotoxicity against MCF-7 cancerous cell line with 57.17 µg/mL, 8.13 µg/mL and 28.31 µg/mL IC50 values respectively, suggesting promising properties as anticancer agents in enzyme-based therapy. The results reveal promising biological activities with potential applications in healthcare sector.

Bioinspired Synthesis and Characterization of Dual-Function Zinc Oxide Nanoparticles from Saccharopolyspora hirsuta: Exploring Antimicrobial and Anticancer Activities

Microbial synthesis offers a sustainable and eco-friendly approach for nanoparticle production. This study explores the biogenic synthesis of zinc oxide nanoparticles (ZnO-NPs) utilizing the actinomycete Saccharopolyspora hirsuta (Ess_amA6) isolated from Tapinoma simrothi. The biosynthesized ZnO-NPs were characterized using various techniques to confirm their formation and properties. UV-visible spectroscopy revealed a characteristic peak at 372 nm, indicative of ZnO-NPs. X-ray diffraction (XRD) analysis confirmed the crystalline structure of the ZnO-NPs as hexagonal wurtzite with a crystallite size of approximately 37.5 ± 13.60 nm. Transmission electron microscopy (TEM) analysis showed the presence of both spherical and roughly hexagonal ZnO nanoparticles in an agglomerated state with a diameter of approximately 44 nm. The biogenic ZnO-NPs exhibited promising biomedical potential. They demonstrated selective cytotoxic activity against human cancer cell lines, demonstrating higher efficacy against Hep-2 cells (IC50 = 73.01 µg/mL) compared to MCF-7 cells (IC50 = 112.74 µg/mL). Furthermore, the biosynthesized ZnO-NPs displayed broad-spectrum antimicrobial activity against both Pseudomonas aeruginosa and Staphylococcus aureus with clear zones of inhibition of 12.67 mm and 14.33 mm, respectively. The MIC and MBC values against P. aeruginosa and S. aureus ranged between 12.5 and 50 µg/mL. These findings suggest the potential of S. hirsuta-mediated ZnO-NPs as promising biocompatible nanomaterials with dual applications as antimicrobial and anticancer agents.

Scaling-up strategies for controllable biosynthetic ZnO NPs using cell free-extract of endophytic Streptomyces albus: characterization, statistical optimization, and biomedical activities evaluation

In this study, we identified a suitable precursor and good cellular compartmentalization for enhancing bioactive metabolites to produce biosynthetic zinc oxide nanoparticles (ZnO NPs). An effective medium for cultivating endophytic Streptomyces albus strain E56 was selected using several optimized approaches in order to maximize the yield of biosynthetic ZnO NPs. The highest biosynthetic ZnO NPs yield (4.63 g/L) was obtained when pipetting the mixed cell-free fractions with 100 mM of zinc sulfate as a precursor. The generation of biosynthetic ZnO NPs was quickly verified using a colored solution (white color) and UV-Visible spectroscopy (maximum peak, at 320 nm). On a small scale, the Taguchi method was applied to improve the culture medium for culturing the strain E56. As a result, its cell-dry weight was 3.85 times that of the control condition. And then the biosynthesis of ZnO NPs (7.59 g/L) was increased by 1.6 times. Furthermore, by using the Plackett-Burman design to improve the utilized biogenesis pathway, the biosynthesis of ZnO NPs (18.76 g/L) was increased by 4.3 times. To find the best growth production line, we used batch and fed batch fermentation modes to gradually scale up biomass output. All kinetics of studied cell growth were evaluated during fed-batch fermentation as follows: biomass yield was 271.45 g/L, yield coefficient was 94.25 g/g, and ZnO NPs yield was 345.32 g/L. In vitro, the effects of various dosages of the controllable biosynthetic ZnO NPs as antimicrobial and anticancer agents were also investigated. The treatments with controllable biosynthetic ZnO NPs had a significant impact on all the examined multidrug-resistant human pathogens as well as cancer cells.

In Silico Prediction of Secondary Metabolites and Biosynthetic Gene Clusters Analysis of Streptomyces thinghirensis HM3 Isolated from Arid Soil

Natural products produced by microorganisms are considered an important resource of bioactive secondary metabolites, such as anticancer, antifungal, antibiotic, and immunosuppressive molecules. Streptomyces are the richest source of bioactive natural products via possessing a wide number of secondary metabolite biosynthetic gene clusters (SM-BGCs). Based on rapid development in sequencing technologies with advances in genome mining, exploring the newly isolated Streptomyces species for possible new secondary metabolites is mandatory to find novel natural products. The isolated Streptomyces thinghirensis strain HM3 from arid and sandy texture soil in Qassim, SA, exerted inhibition activity against tested animal pathogenic Gram-positive bacteria and pathogenic fungal species. In this study, we report the draft genome of S. thinghirensis strain HM3, which consists of 7,139,324 base pairs (bp), with an average G+C content of 71.49%, predicting 7949 open reading frames, 12 rRNA operons (5S, 16S, 23S) and 60 tRNAs. An in silico analysis of strain HM3 genome by the antiSMASH and PRISM 4 online software for SM-BGCs predicted 16 clusters, including four terpene, one lantipeptide, one siderophore, two polyketide synthase (PKS), two non-ribosomal peptide synthetase (NRPS) cluster)/NRPS-like fragment, two RiPP/RiPP-like (ribosomally synthesised and post-translationally modified peptide product), two butyrolactone, one CDPS (tRNA-dependent cyclodipeptide synthases), and one other (cluster containing a secondary metabolite-related protein that does not fit into any other category) BGC. The presented BGCs inside the genome, along with antibacterial and antifungal activity, indicate that HM3 may represent an invaluable source for new secondary metabolites.

Physiotherapeutic Protocol and ZnO Nanoparticles: A Combined Novel Treatment Program against Bacterial Pyomyositis

Myositis tropicans or pyomyositis is a muscle inflammation resulting from a bacterial infection of skeletal muscle (commonly caused by Staphylococcus aureus) that usually leads to hematogenous muscle seeding. The present study was designed to estimate the role of ZnO-NPs and a physiotherapeutic program in the management of induced biceps femoris atrophy in rats through histological, biochemical, and radiological examinations at different time intervals. At the beginning, several bacterial strains were evaluated through a proteolytic enzyme activity assay and the highest activity was recorded with the Staphylococcus aureus strain. ZnO-NPs were synthesized with the arc discharge method with an average size of 19.4 nm. The antibacterial activity of ZnO-NPs was investigated and it was revealed that the prepared ZnO-NPs showed a minimum inhibitory concentration of 8 µg/mL against the tested bacterium. The cytotoxicity of the prepared ZnO-NPs was tested in C2C12 myoblast cells, and it was elaborated that CC50 was 344.16 µg/mL. Biceps femoris pyomyositis was induced with a potent strain (Staphylococcus aureus); then, a physiotherapeutic program combined with the prepared ZnO-NPs treatment protocol was applied and evaluated. The combined program claimed antibacterial properties, preventing muscle atrophy, and resulted in the most comparable value of muscle mass.