ABSTRACT
Agriculture ecosystems are seriously threatened by lead (Pb) contamination, which impacts plant growth and productivity. In this study, green synthesized manganese oxide nanoparticles (MnO NPs) using citrus peel were used for priming of wheat seeds. For the synthesis of MnO nanoparticles, peel extract of Citrus paradisi and 1 mM solution of manganese acetate were stirred and calcinated at 500 °C. Successful synthesis of MnO NPs was determined using advanced techniques. In Fourier-transform infrared spectroscopy (FTIR), the presence of amines, alkanes, aldehydes, and alcohol molecules, on the surface of MnO NPs, confirmed their stability. X-ray diffraction analysis described their average size (22 nm), while scanning electron microscopy showed tetragonal crystalline shape and nano-flowers structure of MnO NPs. Sharp peaks of energy dispersive x-ray analysis described the presence of oxygen (28.81%) and manganese (71.19%) on MnO NPs. Priming of wheat seeds with synthesized MnO NPs significantly improved the growth attributes of wheat seedlings including the size of leaf, root length, size of shoots, chlorophyll and carotenoid contents, relative water content, decreased relative electrolyte leakage, high proline accumulation and decreased concentration of malondialdehyde. Application of MnO NPs also helped plants to accumulate antioxidant enzymes in their leaves. These results proved that the priming of MnO NPs can greatly reduce lead-induced stress in wheat seedlings and these NPs can also be used for the priming of other crops.
ABSTRACT
Antimicrobial resistance (AMR) is a leading cause of treatment failure for many infectious diseases worldwide. Improper overdosing and the misuse of antibiotics contributes significantly to the emergence of drug-resistant bacteria. The co-contamination of heavy metals and antibiotic compounds existing in the environment might also be involved in the spread of AMR. The current study was designed to test the efficacy of heavy metals (arsenic) induced AMR patterns in clinically isolated extended-spectrum ß-lactamase (ESBL) producing bacteria. A total of 300 clinically isolated ESBL-producing bacteria were collected from a tertiary care hospital in Lahore, Pakistan, with the demographic characteristics of patients. After the collection of bacterial isolates, these were reinoculated on agar media for reidentification purposes. Direct antimicrobial sensitivity testing (AST) for bacterial isolates by disk diffusion methods was used to determine the AST patterns with and without heavy metal. The heavy metal was concentrated in dilutions of 1.25 g/mL. The collected bacterial isolates were isolated from wounds (n = 63, 21%), urine (n = 112, 37.3%), blood (n = 43, 14.3%), pus (n = 49, 16.3%), and aspirate (n = 33, 11%) samples. From the total 300 bacterial isolates, n = 172 were Escherichia coli (57.3%), 57 were Klebsiella spp. (19%), 32 were Pseudomonas aeruginosa (10.6%), 21 were Proteus mirabilis (7%) and 18 were Enterobacter spp. (6%). Most of the antibiotic drugs were found resistant to tested bacteria. Colistin and Polymyxin-B showed the highest sensitivity against all tested bacteria, but when tested with heavy metals, these antibiotics were also found to be significantly resistant. We found that heavy metals induced the resistance capability in bacterial isolates, which leads to higher AMR patterns as compared to without heavy metal tested isolates. The results of the current study explored the heavy metal as an inducer of AMR and may contribute to the formation and spread of AMR in settings that are contaminated with heavy metals.
ABSTRACT
AIMS: Iron oxide nanoparticles (Fe2 O3 NPs) were mycosynthesized using Trichoderma harzianum and applied to control brown rot of apple. The influence of Fe2 O3 NPs on the quality of fruit was also studied. METHODS AND RESULTS: Diseased apple fruits with brown rot symptoms were collected, and the disease-causing pathogen was isolated and identified as Fusarium oxysporum. To control this disease, mycosynthesis of Fe2 O3 NPs was executed using T. harzianum. FTIR spectroscopy revealed the occurrence of stabilizing and reducing agents on NPs. X-ray diffraction (XRD) analysis determined their average size (17.78 nm) and crystalline nature. Energy-dispersive X-ray (EDX) showed strong signals of iron, and scanning electron microscopy (SEM) displayed a high degree of polydispersity of synthesized NPs. Foliar application of NPs significantly reduced brown rot and helped fruits to maintain biochemical and organoleptic properties. Firmness and higher percentage of soluble solids, sugars and ascorbic acid depicted its good quality. CONCLUSION: Environment-friendly mycosynthesized Fe2 O3 NPs can be effectively used to control brown rot of apple. SIGNIFICANCE AND IMPACT OF THE STUDY: Trichoderma harzianum is a famous biocontrol agent, and the synthesis of NPs in its extract is an exciting avenue to control fungal diseases. Due to its nontoxic nature to human gut, it can be applied on all edible fruits.