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.

Bio-Characterization and Liquid Chromatography-Mass Spectrometry Analysis of Exopolysaccharides in Biofilm-Producing Cyanobacteria Isolated from Soil Crust: Exploring the Potential of Microalgal Biomolecules.

Exopolysaccharide-producing cyanobacterial strains in biological soil crusts are described, in addition to their chemical properties and antioxidant and flocculation activities. The EPSs from Pudukkottai blackish biological soil crusts (PBBSCs) showed significant amounts of total soluble proteins (0.1687 mg/mL) and carbohydrates (0.8056 mg/mL) compared with the Ariyalur blackish biological soil crusts (ABBSCs). LC-MS analysis of the cyanobacterial polysaccharides revealed the presence of natural sugars such as ribose and glucose/mannose, and uronic acids. The FTIR spectrum showed specific peak for OH and -NH stretching, C-H stretching, and carboxylic acids as the dominant groups in EPS. The in vitro DPPH assay of EPSs from PBBSCs showed 74.3% scavenging activity. Furthermore, the reducing power was determined to be 0.59 ata 500 mg/mL concentration, respectively. The extracted EPSs from the biological soil crust flocculated Kaolin clay suspension maximum at 500 mg/mL. Consequently, the cyanobacterial strain and exopolysaccharide characterization from the sacred forest's biological soil crust were analyzed for their bioactive potential, bio-crust diversity, and distribution.

Simple Approaches for the Synthesis of AgNPs in Solution and Solid Phase Using Modified Methoxypolyethylene Glycol and Evaluation of Their Antimicrobial Activity.

PURPOSE: Simple methodology for preparation of metal nanoparticles such as AgNPs uses an methanolic aqueous medium at room temperature or a solvent-free procedure under microwave irradiation. The prepared AgNPs showed a significant antimicrobial effect against Gram-positive bacteria, Gram-negative bacteria, and fungi. METHODS: The modified methoxypolyethylene glycol bishydrazino-s-triazine (mPEGTH2) showed remarkable activity for reducing Ag+ to Ag0 in an aqueous methanolic solution and using a solvent-free method (solid phase) under microwave irradiation. In the solid phase synthesis, the size and shape of the AgNPs can be controlled by varying the weight ratio of mPEGTH2 to AgNO3 used. In addition, the antimicrobial activity depends on the ratio of mPEGTH2 to AgNO3. The mPEGTH2-AgNPs (2:1) demonstrated higher antimicrobial activity compared to mPEGTH2-AgNPs (1:1) against Gram-positive bacteria, Gram-negative bacteria, and C.albicans. RESULTS: This work presents simple methods for the synthesis of AgNPs using modified methoxypolyethylene glycol with bishydrazino-s-triazine (mPEGTH2); a solution method, using methanol-water medium at room temperature, and a solvent-free (solid phase) method, employing microwave irradiation or direct heating which could be used for the preparation of AgNPs on large scale. In the solid phase, ratios of mPEGTH2 to AgNO3 (1:1 or 2:1, respectively) are very important to control the size and shape of AgNPs. While in solution phase is not necessary where the molar ratio used is 10:1. Most of the experimental methods resulted in AgNPs ranging in size from 7 to 10 nm as observed from XRD and TEM characterization. The antimicrobial activity of the AgNPs was also dependent on the weight ratio of mPEGTH2 to AgNO3, with a large effect as observed when using the solvent-free method. The mPEGTH2-AgNPs (2:1) demonstrated higher antimicrobial activities compared to mPEGTH2-AgNPs (1:1) against S. aureus, S. epidermidis, E. faecalis, E. coli, P. aeruginosa, S. typhimurium, and C. albicans. In all cases, the MICs and MBCs of mPEGTH2-AgNPs (1:1) were lower than those of mPEGTH2-AgNPs (2:1). CONCLUSION: In summary, mPEGTH2-AgNPs (2:1) is a promising candidate to kill pathogenic microbes. In particular, the method used for the preparation of AgNPs by using polyethylene glycol polymer modified with bishydrazino-s-triazine has the most potential and would be the most cost-effective method. This method of the synthesis of nanoparticles may be suitable for the preparation of other metal nanoparticles, which would allow for numerous applications in medicinal and industrial.

Anti-microbiological activities of bio-synthesized silver Nano-stars by Saccharopolyspora hirsuta.

A novel strain of Saccaropolyspora hirsuta was isolated from an insect Tapinoma simrothi for the first time and was morphologically and physiologically characterized. It was genetically identified using 16S rRNA and sequence similarity percentage in genbank with closely related species as strain ess_amA6 of Saccaropolyspora hirsuta. The accession number of strain ess_amA6 is KF996506. Antagonistic activity of strain ess_amA6 against some pathogenic Gram positive and negative bacteria, and unicellular fungus Candida albicans was studied. In addition, star shaped silver nanoparticles were biosynthesized using strain ess_amA6. The silver Nano stars were characterized by UV-us spectrophotometer. Fourier transform infrared spectroscopy analysis confirmed the conversion of Ag+ ions to Nano silver due to the reduction by capping material of extract. Transmission electron microscopically studies of biosynthesized Nano silver particles showed that they are spherical ranging from 10 nm to 30 nm in size. Silver atoms were checked in Nano sample by Energy Dispersive X-ray spectroscopy. Bioactivity of biosynthesized Nano silver was observed against some pathogenic microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Salmonella typhi, pseudomonas aeruginosa, Klebsiella pneumonia and Candida albicans. These tested microbes were highly sensitive to Nano silver. This study recommended that strain ess_amA6 can be used to effectively biosynthesize bioactive Nano silver compounds.

Antimicrobial activity of some plant extracts against bacterial strains causing food poisoning diseases.

Prevention of food spoilage and food poisoning pathogens is usually achieved by use of chemical preservatives which have negative impacts including: human health hazards of the chemical applications, chemical residues in food & feed chains and acquisition of microbial resistance to the used chemicals. Because of such concerns, the necessity to find a potentially effective, healthy safer and natural alternative preservatives is increased. Within these texts, Plant extracts have been used to control food poisoning diseases and preserve foodstuff. Antimicrobial activity of five plant extracts were investigated against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi using agar disc diffusion technique. Ethanolic extracts of Punica granatum, Syzygium aromaticum, Zingiber officinales and Thymus vulgaris were potentially effective with variable efficiency against the tested bacterial strains at concentration of 10 mg/ml while extract of Cuminum cyminum was only effective against S. aureus respectively. P. granatum and S. aromaticum ethanolic extracts were the most effective plant extracts and showed bacteriostatic and bactericidal activities against the highly susceptible strains of food borne pathogenic bacteria (S. aureus and P. aeruginosa) with MIC's ranged from 2.5 to 5.0 mg/ml and MBC of 5.0 and 10 mg/ml except P. aeruginosa which was less sensitive and its MBC reached to 12.5 mg/ml of S. aromaticum respectively. These plant extracts which proved to be potentially effective can be used as natural alternative preventives to control food poisoning diseases and preserve food stuff avoiding healthy hazards of chemically antimicrobial agent applications.

Extraction and Characterization of Polyhydroxybutyrates (PHB) from Bacillus thuringiensisKSADL127 Isolated from Mangrove Environments of Saudi Arabia

ABSTRACTPolyhydroxybutyrate (PHB) is a renowned biodegradable plastic that do not release any toxins or residues in the environment like petroleum based plastics. In the present study, 50 bacteria isolated from mangrove niche, Saudi Arabia, were screened for maximum PHB production. All the 50 strains showed positive for PHB production, of which one strain showed maximum of 137 mgL-1. The most PHB accumulated bacterium was selected and identified asBacillus thuringiensis KSADL127, based on phenotypic characterization and 16S rRNA sequence analysis. Characterization of extracted PHB was carried out by FT-IR, NMR, UV spectroscopy, DSC, TGA, and LC-MS, which later confirmed the presence of intracellular accumulated polymer and substantiated as PHB.