A cerium-based metal–organic framework (Ce-MOF, denoted as AU-1) was synthesized using a solvothermal method by employing 4,4′,4′′-nitrilotribenzoic acid (H3NTB) as the linker and cerium clusters as the metal center.

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The present study aimed to evaluate the quality of fresh sushi in Egypt. Fifty samples of sushi (Salmo salar) were collected from restaurants in Alexandria, Egypt. Paraffin, semi-thin and ultra-thin sections were used for parasitological analysis by light and transmission electron microscopy. Bacteria were isolated by the dilution plate and direct plate methods and identified by a Vitek system. Twenty (40%) of the total examined samples showed microsporidia and helminth metacercariae infections. Histochemical stains showed distinct pinkish-red pyriform microspores embedded in muscular tissue stained with Gram, periodic acid-Schiff (PAS), and Ziehl–Neelsen (ZN) stains. Semi-thin sections showed double membrane xenoma-inducing granulomas containing spores at different developmental stages. Empty sporophorous vesicles and free spores were observed in the electron microscopic images. A bacteriological assay showed forty samples (80%) contaminated with human pathogenic bacteria with the average total bacterial counts ranging from 32 to 526 CFU/g. Four species of human pathogenic bacteria were identified in the examined samples, namely Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Serratia plymuthica in 40, 38, 11, and 6 samples, respectively. These constitute the first record of fresh sushi product in Egypt and indicate the potential pathogenicity associated with raw seafood products.

BackgroundCadmium (Cd) is a highly toxic heavy metal. Its emission is suspected to be further increased due to the dramatic application of ash to agricultural soils and newly reclaimed ones. Thereby, Cd stress encountered by plants will exacerbate. Acute and chronic exposure to Cd can upset plant growth and development and ultimately causes plant death. Microorganisms as agriculturally important biofertilizers have constantly been arising as eco-friendly practices owing to their ability to built-in durability and adaptability mechanisms of plants. However, applying microbes as a biofertilizer agent necessitates the elucidation of the different mechanisms of microbe protection and stabilization of plants against toxic elements in the soil. A greenhouse experiment was performed using Trichoderma harzianum and plant growth-promoting (PGP) bacteria (Azotobacter chroococcum and Bacillus subtilis) individually and integrally to differentiate their potentiality in underpinning various resilience mechanisms versus various Cd levels (0, 50, 100, and 150 mg/kg of soil). Microorganisms were analyzed for Cd tolerance and biosorption capacity, indoleacetic acid production, and phosphate and potassium solubilization in vitro. Plant growth parameters, water relations, physiological and biochemical analysis, stress markers and membrane damage traits, and nutritional composition were estimated.ResultsUnequivocal inversion from a state of downregulation to upregulation was distinct under microbial inoculations. Inoculating soil with T. harzianum and PGPB markedly enhanced the plant parameters under Cd stress (150 mg/kg) compared with control plants by 4.9% and 13.9%, 5.6% and 11.1%, 55.6% and 5.7%, and 9.1% and 4.6% for plant fresh weight, dry weight, net assimilation rate, and transpiration rate, respectively; by 2.3% and 34.9%, 26.3% and 69.0%, 26.3% and 232.4%, 135.3% and 446.2%, 500% and 95.6%, and 60% and 300% for some metabolites such as starch, amino acids, phenolics, flavonoids, anthocyanin, and proline, respectively; by 134.0% and 604.6% for antioxidants including reduced glutathione; and by 64.8% and 91.2%, 21.9% and 72.7%, and 76.7% and 166.7% for enzymes activity including ascorbate peroxidase, glutathione peroxidase, and phenylalanine ammonia-lyase, respectively. Whereas a hampering effect mediated by PGP bacterial inoculation was registered on levels of superoxide anion, hydroxyl radical, electrolyte leakage, and polyphenol oxidase activity, with a decrease of 0.53%, 14.12%, 2.70%, and 5.70%, respectively, under a highest Cd level (150 mg/kg) compared with control plants. The available soil and plant Cd concentrations were decreased by 11.5% and 47.5%, and 3.8% and 45.0% with T. harzianum and PGP bacterial inoculation, respectively, compared with non-inoculated Cd-stressed plants. Whereas, non-significant alternation in antioxidant capacity of sunflower mediated by T. harzianum action even with elevated soil Cd concentrations indicates stable oxidative status. The uptake of nutrients, viz., K, Ca, Mg, Fe, nitrate, and phosphorus, was interestingly increased (34.0, 4.4, 3.3, 9.2, 30.0, and 1.0 mg/g dry weight, respectively) owing to the synergic inoculation in the presence of 150 mg of Cd/kg.ConclusionsHowever, strategies of microbe-induced resilience are largely exclusive and divergent. Biofertilizing potential of T. harzianum showed that, owing to its Cd biosorption capability, a resilience strategy was induced via reducing Cd bioavailability to be in the range that turned its effect from toxicity to essentiality posing well-known low-dose stimulation phenomena (hormetic effect), whereas using Azotobacter chroococcum and Bacillus subtilis, owing to their PGP traits, manifested a resilience strategy by neutralizing the potential side effects of Cd toxicity. The synergistic use of fungi and bacteria proved the highest efficiency in imparting sunflower adaptability under Cd stress.

Plant responses during the pathogen infection and the pathogen control reflect its strategies to protect its cells. This work represents the Alternaria cerealis MT808477 as a phytopathogen causing leaf spot disease in tomatoes. A. cerealis was identified morphologically and genetically by 18SrRNA, and its pathogenicity was confirmed by light and scanning electron microscopy. Trichoderma harzianum has the ability to control A. cerealis MT808477 by stimulating various cell responses during the controlling process. The cell behavior during the biological control process was observed by analyses of total phenol, flavonoids, terpenoids, antioxidant, malondialdehyde and antioxidant enzymes (catalase and peroxidase). The extracts of infected tomato leaves were tested against plant and human pathogenic microorganisms. Results showed that the biological control process activates the defense cell strategies by increasing the plant tolerance, and activation of plant defense systems. The total phenol, flavonoids, terpenoids, antioxidant and malondialdehyde were increased after 48 h. Catalase and peroxidase were increased in infected tomato plants and decreased during the biological control process, reflecting the decrease of cell stress. Leaves extract inhibited the growth of nine plant and human pathogenic microorganisms. Biological control represents a safe and effective solution to phytopathogens that decreases plant cell stress by stimulating various defensive agents.

Correction for ‘A cerium-based MOFzyme with multi-enzyme-like activity for the disruption and inhibition of fungal recolonization’ by Hani Nasser Abdelhamid et al., J. Mater. Chem. B, 2020, DOI: 10.1039/d0tb00894j.

Postharvest fungal infection is the common cause of fresh fruit losses. Thus, effective antifungal agents are highly required. Herein, copper‐based metal–organic frameworks (MOFs) were used as a precursor for the synthesis of copper oxide (CuO) embedded into carbon (CuO@C). The materials' crystallinity was confirmed using X‐ray diffraction. X‐ray photoelectron spectroscopy (XPS) and atomic absorption spectroscopy (AAS) approve the elemental species and concentration of copper in the synthesized materials. Transmission electron microscopy (TEM), high‐resolution TEM (HR‐TEM), and scanning electron microscopy (SEM) reveal the successful formation of CuO‐embedded C, that is, CuO@C, with a particle size of 36–123 nm. CuO@C nanoparticles are used as an antifungal agent against four economic postharvest plant pathogens; Alternaria alternata (black spot disease of tomato), Fusarium oxysporum (rot disease of tomato), Penicillium digitatum (gray mold disease of lemon), and Rhizopus oryzae (soft rot disease of banana). The inhibition zones were 36 ± 0.5, 20.2 ± 0.4, 16 ± 0.5, and 10.2 ± 0.1 mm for R. oryzae, P. digitatum, F. oxysporum, and A. alternata, respectively. CuO@C antifungal action includes significant inhibition of cellulases and amylase enzyme activity, decreasing the potentiality of fungal pathogenicity and fruit disease. CuO@C exhibited high antifungal activity against postharvest antifungal species.

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