Manganese peroxidase (MnP) was produced from white rot edible mushroom Pleurotus ostreatus on the culture filtrate. The enzyme was purified to homogeneity using (NH4)2SO4 precipitation, DEAE-Sepharose and Sephadex G-100 column chromatography. The final enzyme activity achieved 81 U mL−1, specific activity 78 U mg−1 with purification fold of 130 and recovery 1.2% of the crude enzyme. SDS-PAGE indicated that the pure enzyme have a molecular mass of approximately 42 kDa. The optimum pH was between 4–5 and the optimum temperature was 25 °C. The pure MnP activity was enhanced by Mn2+, Cu2+, Ca2+ and K+ and inhibited by Hg+2 and Cd+2. H2O2 at 5 mM enhanced MnP activity while at 10 mM inhibited it significantly. The MnP-cDNA encoding gene was sequenced and determined (GenBank accession no. AB698450.1). The MnP-cDNA was found to consist of 497 bp in an Open Reading Frame (ORF) encoding 165 amino acids. MnP from P. ostreatus could detoxify aflatoxin B1 (AFB1) depending on enzyme concentration and incubation period. The highest detoxification power (90%) was observed after 48 h incubation at 1.5 U mL−1 enzyme activities.
The biosynthesis of nanoparticles has received increasing interest because of the growing need to develop safe, cost-effective and environmentally friendly technologies for the synthesis of nano-materials. In this study, silver nanoparticles (AgNPs) were synthesized using a reduction of aqueous Ag(+) ions with culture supernatant from Pleurotus ostreatus. The bioreduction of AgNPs was monitored by ultra violet-visible spectroscopy and the obtained AgNPs were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy techniques. TEM studies showed the size of the AgNPs to be in the range of 4-15 nm. The formation of AgNPs might be an enzyme-mediated extracellular reaction process. Furthermore, the antifungal effect of AgNPs against Candida albicans as compared with commercially antifungal drugs was examined. The effect of AgNPs on dimorphic transition of C. albicans was tested. The anticancer properties of AgNPs against cells (MCF-7) were also evaluated. AgNPs caused a significant decrease in cell viability of an MCF-7 cell line (breast carcinoma). Exposure of MCF-7 cells with AgNPs resulted in a dose-dependent increase in cell growth inhibition varying from 5 to 78 % at concentrations in the range of 10-640 μg ml(-1). The present study demonstrated that AgNPs have potent antifungal, antidimorphic, and anticancer activities. The current research opens a new avenue for the green synthesis of nano-materials.
Arbuscular mycorrhizal fungi (AMF) and elevated CO2 (eCO2) have been effectively integrated to the agricultural procedures as an ecofriendly approach to support the production and quality of plants. However, less attention has been given to the synchronous application of AMF and eCO2 and how that could affect the global plant metabolism. This study was conducted to investigate the effects of AMF and eCO2, individually or in combination, on growth, photosynthesis, metabolism and the functional food value of Thymus vulgare. Results revealed that both AMF and eCO2 treatments improved the photosynthesis and biomass production, however much more positive impact was obtained by their synchronous application. Moreover, the levels of the majority of the detected sugars, organic acids, amino acids, unsaturated fatty acids, volatile compounds, phenolic acids and flavonoids were further improved as a result of the synergistic action of AMF and eCO2, as compared to the individual treatments. Overall, this study clearly shows that co-application of AMF and eCO2 induces a synergistic biofertilization impact and enhances the functional food value of T. vulgare by affecting its global metabolism.
The antifungal efficiency of Zinc oxide nanoparticles (ZnO NPs) was investigated against two pathogenic fungal species, F. oxysporum and P. expansum. The two fungi were identified at molecular level by nuclear ribosomal DNA internal transcribed spacer (ITS) identities. They have been submitted to the GenBank with accession numbers of AB753032 and AB753033 for F. oxysporum and P. expansum, respectively. The antifungal activity of ZnO NPs was found to be concentration dependent. Hence, maximal inhibition of mycelial growth corresponded to the highest experimental concentration (12 mg L −1), where 77 and 100% growth inhibition was observed for F. oxysporum and P. expansum, respectively. The effect of ZnO NPs on the mycotoxins fusaric acid and patulin production by F. oxysporum and P. expansum, respectively, was investigated using HPLC quantification. It was observed that ZnO NPs prevented both mycotoxins synthesis in a concentration dependent manner. Fusaric acid was reduced from 39.0 to 0.20 mg g-1 while patulin production was reduced from 14.2 to 1.10 mg g-1 in control and 12 mg L −1 ZnO NPs treated samples, respectively. The scanning electron microscopy (SEM) revealed obvious deformation in the growing mycelia treated with ZnO NPs in F. oxysporum which may be the cause of growth inhibition.
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