Nanoparticles have recently emerged as a popular research topic. Because of their potential applications in therapeutic applications, biosynthesized silver nanoparticles (Bio-AgNPs) have gained much attention in recent years. Cell-free extracts (CFE) from a marine culture of actinobacteria and silver nitrate were used to reduce Ag+ ions and create Bio-AgNPs. Nocardiopsis dasonvillei KY772427, a new silver-tolerant actinomycete strain, was isolated from marine water and used to synthesize AgNPs. In order to characterize Bio-AgNPs, UV-Vis spectral analysis, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and dynamic light scattering spectroscopy (DLS) were all utilized. Using UV–Vis spectroscopy, a peak in the surface plasmon resonance (SPR) spectrum at 430 nm revealed the presence of Bio-AgNPs. The TEM revealed spherical AgNPs with a diameter of 29.28 nm. DLS determined that Bio-AgNPs have a diameter of 56.1 nm and a negative surface charge (−1.46 mV). The minimum inhibitory concentration (MIC) of Bio-AgNPs was determined against microbial strains. Using resazurin-based microtiter dilution, the synergistic effect of Bio-AgNPs with antimicrobials was investigated. Pseudomonas aeruginosa had the lowest MIC of Bio-AgNPs (4 μg/ml). Surprisingly, the combination of antimicrobials and Bio-AgNPs had a significant synergistic effect on the tested strains. The insecticidal activity of Bio-AgNPs (200 μg/ml) against Macrosiphum rosae was found to be maximal after 36 h. Additionally, Bio-AgNPs demonstrated significant scavenging activity against 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH–) radicals, with IC50 values of 4.08 and 8.9 g/ml, respectively. In vitro studies using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed a concentration-dependent decrease in cell viability when CaCo2 cells were exposed to Bio-AgNPs. With the decrease in cell viability, lactate dehydrogenase leakage (LDH) increased. The findings of this study open up a new avenue for the use of marine Nocardiopsis dasonvillei to produce Bio-AgNPs, which have significant antimicrobial, antioxidant, insecticidal, and anticancer potential.
Taify grape is one of the important summer fruits in the Taif area in Saudi Arabia. A part of grape spoiled because by fungi and their toxins, influencing intersection processing, and export, alongside the quality of superior general welfare risk of exposure. The aim of this work was to check the ability of live cells and crude cell-free extracts of the grape epiphytic antagonists Pseudomonas aeruginosa, Bacillus vallismortis and B. amyloliquefaciens to control the transmission of Aspergillus niger, A. parasiticus and A. tubingensis to post-harvest Taify table grape berries (Vitis vinifera L.). Gathering of aflatoxin B1 (AFB1) and ochratoxin A (OTA) was also evaluated. Also, the activity of peroxidase enzyme, total phenol, and lipid peroxidation evaluated. The healthy and injured grape berry inoculated or suspended in the live bacterium cell suspension or bacteria free extract were challenged by the above fungi and stored at 5°C and 20°C for 28 and 50 days, individually. The treatments were effective for lessening the parasites misuse, spoil advance, and decay rate, and AFB1 and OTA aggregation. A pre-dousing of the in-place grape berries was prevalent. The peroxidase enzyme and the total phenol expanded further, slightness the lipid peroxidation, all reinforce the antagonists. The bacteria, their cell-free extracts, the incited peroxidase enzyme, total phenol and the brought down lipid peroxidation, made the medium ominous to the fungal establishment and further developing, and after that developing aggregate AFB1 and OTA ceased. Additional work expected to recognize the bacterial causal variable as well as the active metabolites.
Alginates are regarded as high-value biomacromolecules. A pursuit for new bacterial species that can produce novel alginates for various applications in different industries including the pharmaceutical and food industries as well as the field of medicine is still needed. Variations in the molecular weight and sugar composition of alginates depend on the culture medium composition and different physical conditions provided during fermentation. The aim of this study was to obtain a maximum alginate production by the potent Egyptian bacterial strain Azotobacter vinelandii , out of the 30 tested Azotobacter isolates. The composition of the production medium and environmental growth conditions during fermentation were optimized to ensure consistency and to enhance alginate production. Nine variables were optimized using the Plackett-Burman randomization method. Eighteen trials were performed to verify the variables to obtain high alginate production levels. Temperature as well as sucrose and NaCl concentrations have been found to affect the alginate production by A. vinelandii significantly and were therefore chosen for further improvement of the medium using the Box-Behnken design. The Box-Behnken model was optimized mathematically using the Excel solver. The results were analyzed statistically by ANOVA multiple regression analysis and different statistical methods (coefficient, standard error, t statistic, and confidence interval). On using the Plackett-Burman and Box-Behnken designs, the biggest alginate production rates were found to be 3.8 and 4.94 g/l/day, respectively. Addition of 00.1 g/l MgSO 4 , 0.01 g/l FSO4, and 0.001 g/l NaMoO 4 to the culture medium further enhanced the alginate production and yielded 5.4 g/l/day and 8.5 g/l/day. Thus, the obtained alginate was purified using Sephadex G-100 Gel chromatography and compared with a standard by IR correlation. The alginate was found to be composed of 50-70% carbohydrates and 60-80% uronic acid. The techniques used in this survey were found useful for improving the production of alginates.
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