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THE ISSUE of heavy metals (HMs) contamination has become a matter of significant international concern. As a result, various techniques employed by biological systems to eliminate HMs are being examined. Specific HMs, such as cadmium, zinc, nickel, copper, and cobalt, are necessary for the physiological functions of both symbiotic and non-symbiotic nitrogen-fixing bacteria (NFB) when present in minor amounts. However, elevated levels of HM concentrations can impair the functioning of NFB and their symbiotic relationship. The present investigation focuses on how the NFB, resists the HMs toxicity and increases plant growth to assist in accomplishing crop cultivation in metal-contaminated locations. Numerous mechanisms were reviewed for HMs resistance such as organic ligands and thiols which annoy the metal ions constructing a complex and blocking cell impairment. This review summarizes that soil inoculation with HMs-resistant NFB reflects numerous beneficial effects in agricultural systems, therefore its application is considered a bioremediating tools that have economic and ecological importance. In addition, the current review discussed the role of NFB in reducing the toxic impacts of HMs on plant life. [ABSTRACT FROM AUTHOR]

Efficacies of plant metabolites are known to be dependent on their extraction methods. Yields and compositions of phytoconstituents in the extract were evaluated following supercritical fluid extraction (SFE) of Vitex agnus-castus leaves, static extraction times (SET) for 30 min, subsequently dynamic extraction time (DET) for 30 min (condition A) and SET for 0 min followed by DET for 60 min (condition B). The extract exposed to condition B gave an extraction yield of 0.169 g compared to 0.115 g for condition A. High-performance liquid chromatography analysis revealed compounds including cinnamic acid, kaempferol, ferulic acid, rutin, and caffeic acid, in high concentrations in the extract exposed to condition B. Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis, and Candida albicans were more affected by the condition B with 32 ± 0.1, 20 ± 0.2, 32 ± 0.2, 35 ± 0.2, and 40 ± 0.1 mm inhibition zones, respectively. Less MIC and MBC were noticed of the exposed extract to condition B than to condition A against C. albicans and bacteria. The IC50 of the extract exposed to condition B was high against ovarian tumor cells. Presently the efficacy of the exposed extract to condition B for wound healing process was documented. [ABSTRACT FROM AUTHOR]

In the current investigation, the antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) formed by an aqueous extract of Psidium guajava leaves against foodborne pathogenic bacterial strains was investigated. To achieve this goal, 33 bacterial isolates were obtained from spoiled fruits. Among these isolates, 79% showed cellulase activity, 82% showed amylase activity, 81% exhibited xylanase potential, and 65% exhibited lipase activity. Moreover, 12 isolates showed complete hemolysis (β-hemolysis). The identification of these isolates was done using sequencing and amplification of 16s rRNA as Staphylococcus aureus (two strains), Pseudomonas syringae (one strain), E. coli (two strains), Salmonella typhimurium (two strains), Listeria monocytogenes (one isolate), Bacillus cereus (two isolates), and Bacillus subtilis (two isolates). The formed ZnO-NPs by aqueous Psidium guajava leaf extract were characterized using UV, FT-IR, TEM, EDX, XRD, DLS, and Zeta potential. The data revealed the successful formation of a spherical shape, crystallographic structure, and well-arranged ZnO-NPs. FT-IR showed the effect of different functional groups in the plant extract in the formation of ZnO-NPs through reducing, capping, and stabilizing of end products. Moreover, EDX analysis showed that the Zn ion occupied the main component of the produced NPs. Interestingly, the obtained bacterial strains showed varied sensitivity toward green-synthesized ZnO-NPs. The growth inhibition of foodborne pathogenic strains by ZnO-NPs was concentration dependent, forming a zone of inhibition in the range of 20–23 mm at a concentration of 200 µg mL−1, which decreased to 15–18 mm at 100 µg mL−1. Moreover, the values of MIC were 25 and 50 µg mL−1 based on the bacterial strain. Overall, the green-synthesized ZnO-NPs can be a useful approach for inhibiting the growth of spoilage bacterial strains that destroy fruits and hence reduce the harmful effects of traditional treatment methods on the environment and human health. [ABSTRACT FROM AUTHOR]

The biomass filtrate of the endophytic bacterial strain Bacillus amyloliquefaciens Fa.2 was utilized for the eco-friendly production of silver nanoparticles (Ag-NPs). The yellowish-brown color's optical properties showed a maximum surface plasmon resonance at 415 nm. The morphological and elemental composition analysis reveals the formation of spherical shapes with sizes of 5–40 nm, and the Ag ion comprises the major component of the produced Ag-NPs. X-ray diffraction confirmed the crystalline structure, whereas dynamic light scattering reveals the high stability of synthesized Ag-NPs with a polydispersity index of 0.413 and a negative zeta potential value. The photocatalytic experiment showed the efficacy of Ag-NPs to degrade methylene blue with maximum percentages of 73.9 ± 0.5 and 87.4 ± 0.9% under sunshine and UV irradiation, respectively, compared with 39.8% under dark conditions after 210 min. Additionally, the reusability of Ag-NPs was still more active for the fifth run, with a percentage decrease of 11.6% compared with the first run. Interestingly, the biogenic Ag-NPs showed superior antimicrobial activity against different pathogenic Gram-negative bacteria (MIC = 6.25 µg mL−1), Gram-positive bacteria (MIC = 12.5 µg mL−1), and uni- and multicellular fungi (MIC = 12.5 µg mL−1). Moreover, the biosynthesized Ag-NPs could target cancer cells (Pc3 and Mcf7) at low concentrations compared with normal cell (Vero) lines. The IC50 of normal cells is 383.7 ± 4.1 µg mL−1 compared with IC50 Pc3 (2.5 ± 3.5 µg mL−1) and McF7 (156.1 ± 6.8 µg mL−1). Overall, the bacterially synthesized Ag-NPs showed multifunctional features to be used in environmental catalysis and biomedical applications. [ABSTRACT FROM AUTHOR]

Green routes for the bio-designing of bicomponent nanocomposites and their utilizations have attracted many investigators. Bio-designing of CuO@ZnO nanocomposites was performed using spent mushroom substrate (SMS). Ultraviolet-spectrophotometry, transmission electron microscopy, Fourier transform infrared (FT-IR), and energy dispersive Xray (EDX), besides X-ray diffraction (XRD) were exploited to characterize the synthesized CuO@ZnO. The dimensions of CuO@ZnO nanocomposites ranged from 31.4 and 95.9 nm. Both FT-IR and EDX analyses displayed the presence of some organic constituents from the SMS that joined to the surface of the fabricated CuO@ZnO nanocomposite. CuO@ZnO nanocomposite succeeded in inhibiting Candida albicans with an inhibition zone of 33.5 ± 2 mm. C. albicans biofilm was affected by CuO@ZnO nanocomposite with biofilm inhibition of 25.08, 68.70, and 88.56% at 25, 50, and 75% of minimum inhibitory concentration, respectively. Molecular docking studies showed substantial binding affinities, as well as common hydrogen bonds. Optimum binding sites for CuO and ZnO nanoparticles were found to have binding affinities of interactions with 4YDE, 3DRA, and 1EAG proteins of C. albicans, resulting in, respectively, -2.7942, -3.30097, and -2.52129 kcal/mol, and - 3.78244, -4.6029, and -4.1352 kcal/mol values. The findings suggest that CuO@ZnO nanocomposite can effectively suppress C. albicans growth. [ABSTRACT FROM AUTHOR]

Plants represent a great source of medicines, and for their components to be discovered, extraction processes must be developed, especially methods based on green technology. Supercritical fluid extraction (SFE) was employed as a green method for Moringa oleifera extraction in the present investigation. The maximum yield of extraction was obtained at 25 MPa. Moreover, the extraction at 25 MPa induced the release of various phenols and flavonoids, as analyzed via high-performance liquid chromatography. The investigation revealed the concentrations of chlorogenic, gallic, rosmarinic, and coumaric acids to be 150.59, 89.90, 44.75, and 29.41 μg/mL, respectively at 25 MPa. However, their concentrations were 0.73, 1.53, 0.24, and 0.04 μg/mL, respectively at 15 MPa; vs. 4.73, 2.62, 1.06, and 0.50 at 35 MPa, respectively. Totals of saponin, flavonoid, phenolic, tannins, and alkaloid were recorded in maximum yield at 25 MPa. Moringa oleifera extracted at 35 MPa reflected highest inhibition zones of 27 ± 0.1, 30 ± 0.2, and 30 ± 0.1 mm against C. glabrata, C. tropicalis, and C. albicans, correspondingly. α-Amylase and α-glucosidase activities were greatly suppressed by the M. oleifera extract at 25 MPa with less IC50 (12.97 μg/mL and 6.0 µg/mL), than the IC50 (53.46 and 22.02 μg/mL) at 15 MPa, compared with acarbose IC50 (5.52 and 2.64 μg/mL), correspondingly. [ABSTRACT FROM AUTHOR]

Salinity has become a major environmental concern of agricultural lands, impairing crop production. The current study aimed to examine the role of zinc oxide nanoparticles (ZnO NPs) in reducing the oxidative stress induced by salinity and the overall improvement in phytochemical properties in barley. A total of nine different barley genotypes were first subjected to salt (NaCl) stress in hydroponic conditions to determine the tolerance among the genotypes. The genotype Annora was found as most sensitive, and the most tolerant genotype was Awaran 02 under salinity stress. In another study, the most sensitive (Annora) and tolerant (Awaran 02) barley genotypes were grown in pots under salinity stress (100 mM). At the same time, half of the pots were provided with the soil application of ZnO NPs (100 mg kg−1 ), and the other half pots were foliar sprayed with ZnO NPs (100 mg L−1 ). Salinity stress reduced barley growth in both genotypes compared to control plants. However, greater reduction in barley growth was found in Annora (sensitive genotype) than in Awaran 02 (tolerant genotype). The exogenous application of ZnO NPs ameliorated salt stress and improved barley biomass, photosynthesis, and antioxidant enzyme activities by reducing oxidative damage caused by salt stress. However, this positive effect by ZnO NPs was observed more in Awaran 02 than in Annora genotype. Furthermore, the foliar application of ZnO NPs was more effective than the soil application of ZnO NPs. Findings of the present study revealed that exogenous application of ZnO NPs could be a promising approach to alleviate salt stress in barley genotypes with different levels of salinity tolerance [ABSTRACT FROM AUTHOR]