Biogenic silver nanoparticles eradicate of Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) isolated from the sputum of COVID-19 patients.

In recent investigations, secondary bacterial infections were found to be strongly related to mortality in COVID-19 patients. In addition, Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria played an important role in the series of bacterial infections that accompany infection in COVID-19. The objective of the present study was to investigate the ability of biosynthesized silver nanoparticles from strawberries (Fragaria ananassa L.) leaf extract without a chemical catalyst to inhibit Gram-negative P. aeruginosa and Gram-positive Staph aureus isolated from COVID-19 patient's sputum. A wide range of measurements was performed on the synthesized AgNPs, including UV-vis, SEM, TEM, EDX, DLS, ζ -potential, XRD, and FTIR. UV-Visible spectral showed the absorbance at the wavelength 398 nm with an increase in the color intensity of the mixture after 8 h passed at the time of preparation confirming the high stability of the FA-AgNPs in the dark at room temperature. SEM and TEM measurements confirmed AgNPs with size ranges of ∼40-∼50 nm, whereas the DLS study confirmed their average hydrodynamic size as ∼53 nm. Furthermore, Ag NPs. EDX analysis showed the presence of the following elements: oxygen (40.46%), and silver (59.54%). Biosynthesized FA-AgNPs (ζ = -17.5 ± 3.1 mV) showed concentration-dependent antimicrobial activity for 48 h in both pathogenic strains. MTT tests showed concentration-dependent and line-specific effects of FA-AgNPs on cancer MCF-7 and normal liver WRL-68 cell cultures. According to the results, synthetic FA-AgNPs obtained through an environmentally friendly biological process are inexpensive and may inhibit the growth of bacteria isolated from COVID-19 patients.

Production and bioprocessing of camptothecin from Aspergillus terreus, an endophyte of Cestrum parqui, restoring their biosynthetic potency by Citrus limonum peel extracts.

The metabolic potency of fungi as camptothecin producer elevates their prospective use as an industrial platform for commercial production, however, the loss of camptothecin productivity by fungi with the storage and subculturing are the major obstacle. Thus, screening for endophytic fungal isolates inhabiting ethnopharmacological plants with an obvious metabolic stability and sustainability for camptothecin biosynthesis could be one of the most feasible paradigms. Aspergillus terreus ON908494.1, an endophyte of Cestrum parqui was morphologically and molecularly verified, displaying the most potent camptothecin biosynthetic potency. The chemical identity of A. terreus camptothecin was confirmed from the HPLC, FTIR and LC-MS/MS analyses, gave the same molecular structure and mass fragmentation patterns of authentic one. The purified putative camptothecin displayed a strong anticancer activity towards HepG-2 and MCF-7 with IC50 values 0.96 and 1.4 µM, respectively, with no toxicity to OEC normal cells. As well as, the purified camptothecin displayed a significant antifungal activity towards fungal human pathogen Candida albicans, Aspergillus flavus, and A. parasiticus, ensuring the unique structural activity relationships of A. terreus camptothecin, as a powerful dually active anticancer and antimicrobial agent. The camptothecin productivity of A. terreus was maximized by bioprocessing with Plackett-Burman design, with an overall 1.5 folds increment (170.5 µg/L), comparing to control culture. So, the optimal medium components for maximum yield of camptothecin by A. terreus was acid why (2.0 mL/L), Diaion HP20 (2.0 g/L), Amberlite XAD (2.0 g/L), dextrin (5.0 g/L), glucose (10.0 g/L), salicylic acid (2.0 g/L), serine (4.0 g/L), cysteine (4.0 g/L) and glutamate (10.0 g/L), at pH 6 for 15 days incubation. By the 5th generation of A. terreus, the camptothecin yield was reduced by 60%, comparing to zero culture. Interestingly, the productivity of camptothecin by A. terreus has been completely restored and over increased (210 µg/L), comparing to the 3rd generation A. terreus (90 µg/L) upon addition of methanolic extracts of Citrus limonum peels, revealing the presence of some chemical signals that triggers the camptothecin biosynthetic machinery. The feasibility of complete restoring of camptothecin biosynthetic-machinery of A. terreus for stable and sustainable production of camptothecin, pave the way for using this fungal isolate as new platform for scaling-up the camptothecin production.

Biosystematic studies of some Egyptian species of Cestrum (Solanaceae).

Cestrum is the second largest genus of family Solanaceae, after Solanum, distributed in warm to subtropical regions. Species of genus Cestrum are one of the most ethnopharmacological relevant plants, for their broad biological and pharmacological properties. There is a scarcity to taxonomical studies and identification of these plants in Egypt, thus, the objective of this study was to implement various morphological features, chemical markers and molecular tools to emphasize the taxonomical features of the different Cestrum species. Morphologically, the epidermal cells of C. diurnum, C. elegans and C. parqui were irregular with sinuate anticlinal wall patterns for both surfaces, while, C. nocturnum has anticlinal walls, sinuolate with polygonal to irregular epidermal cells on the abaxial surface. The species of Cestrum have hypostomatic leaves, except C. parqui that has amphistomatic leaves. The experimented species of Cestrum have Anomocytic and anisocytic stomata, while, C. elegans has a diacytic stomata. The morphologically identified Cestrum spp were molecular confirmed based on their ITS sequences, the sequences of C. diurnum, C. nocturnum, C. elegans and C. parqui were deposited on genbank with accession # MT742788.1, MT749390.1, MW091481.1 and MW023744.1, respectively. From the SCOT analyses, the four species of Cestrum were grouped into 2 clusters (I, II), cluster I contains C. elegans, C. nocturnum and C. parqui, while cluster II contains only C. diurnum with 100% polymorphism for all primers. From the GC-MS profile, the C. diurnum exhibited a diverse metabolic paradigm, ensuring their richness with different metabolites comparing to other experimented Cestrum species. Among the total resolved metabolites, 15-methyltricyclo 6.5.2-pentadeca-1,3,5,7,9, 11,13-heptene was the highly incident compound in C. elegans (35.89%) followed by C. parqui (21.81%) and C. diurnum (11.28%), while it absent on C. nocturnum. The compound, 2,2',6,6'-tetra-tert-butyl-4,4'-methylenediphenol was highly detected in C. elegans and C. dirunum with minor amounts in the other Cestrum species. Cypermethrin and 3-butynyl-2,2,5-trimethyl-1,3-dioxane-5-methanol were pivotally reported in C. nocturnum. Taken together, from molecular and metabolic markers, C. diurnum, C. parqui and C. elegans have higher proximity unlike to C. nocturnum.