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New properties of nano-materials have made nanotechnology the leading part of biology and medical sciences. Due to their various biomedical properties, iron-based magnetic nanoparticles (MNPs) have been highly considered by biological researchers. Nowadays, increasing resistance to antibiotics is a major problem in treating clinical infections. Finding new antibacterial agents is therefore essential for the treatment of resistant strains. In this study, the iron oxide MNPs were produced using culture-medium supernatant of a newly isolated bacterium to investigate the inhibitory effects of the NPs on strains with a major role in clinical infections. Biosynthesis of iron oxide MNPs were detected by UV-Vis spectroscopy and the average size of particles was estimated by dynamic light scattering technique. The anti-bacterial activity of these NPs against E. coli and S. aureus was investigated using methods for the calculation of bacterial sensitivity coefficient. In the presence of NPs, the highest sensitivity coefficient value was observed for E. coli in 1xMIC concentration. On the other hand, S. aureus showed the lowest value. The death rate of the two strains in contact with NPs followed the first order kinetic equation and the survival rate decreased with the increase of exposure time. The results of this study as well as the high functionality of iron oxide MNPs, make its application desirable in the prevention and treatment of clinical infections.

 

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The aim of this research was to study the effect of iron oxide nanoparticles (FeO NPs) on the growth, differentiation, anatomy, and physiology of pepper (Capsicum annuum L.) on the basis of a completely randomized design in vitro condition. Seedlings were cultured in MS medium containing four concentrations of FeO NPs (0, 1, 10, and 20 mgl^-1). Also, the effect of the different concentrations of FeO NPs on callus formation under two various hormone conditions (0.5mgl^-1 2,4D+0.5 mgl^-1 BAP or 0.5 mgl^-1 BAP+1 mgl^-1 Kin) were assessed. The results showed that the application of FeO NPs significantly increased biomass accumulation in both roots and shoots. Moreover, FeO NPs enhanced the concentrations of photosynthesis pigments (chllrophyll a, chlorophyll b, and carotenoids). The presence of FeO NPs in culture medium affected callus formation in a hormone-dependent manner. Different concentration of FeO NPs induced the callus formation under 2, 4-D and BAP treatments. However, it did not significantly increase callus formation under the kinitin and 2,4-D. The findings of this research indicated that the application of FeO NPs at optimized doses may improve plant production, especially in vitro condition.

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Superparamagnetic iron oxide nanoparticles (SPIONs) have made extensive advances in nanotechnology. The unique properties of these particles have expanded their application in various fields, including medicine. One of these applications is non-invasive analysis for cell tracking. However, the possibility of toxicity in cells is reported by these nanoparticles. Due to the fact that cellular damage caused by iron oxide nanoparticles is concentration-dependent, the determination of the appropriate  concentration of iron oxide nanoparticles is very important to prevent cell damage or cell death due to apoptosis. The aim of this study was to find a concentration of SPIONs which does not result in apoptosis. Therefore, the effects of different concentrations of iron oxide nanoparticles on cell survival were investigated, and the their effects on increased gene expression involved in apoptosis (p53) in human amniotic membrane derived mesenchymal stem cells (hAMSCs) were evaluated. First, stem cells were extracted from human amniotic membrane tissue and cultured. To demonstrate the multipotent characteristic of hAMSCs, these cells were differentiated into adipose, bone, and chondrocyte cell lines. Then, the viability of the cells treated with different concentrations of iron oxide nanoparticles (200, 150, 100, 50, 0 μg / ml) over a period of 24 and 48 hours was evaluated by MTT method. The effect of the concentrations of 0, 100,150 and 200 μg / ml of nanoparticles after 24 hours in hAMSCs was investigated for the expression of p53 gene by Real-Time PCR. hAMSCs were spindle-shaped in a two-dimensional culture. Flow cytometry examination of surface markers revealed that these cells were able to express CD 29, CD90 and CD105 but they were unable to express CD34 and CD45. The results of the multi-potency assay of hAMSCs showed that these cells were capable of being differentiated into adipocyte, bone and chondrocyte cell lines. Iron oxide nanoparticles had no significant effect on cell survival at the concentrations of 50 and 100 μg / ml in 24 hours. However, cell viability decreased significantly after the concentration of 150 μg / ml (42 ± 1.4%, p<0. 001. The results of Real-Time PCR  analysis showed that the expression of p53 gene significantly increased at concentrations of 150 (2.4±0.1, P < 0. 001) and 200 μg / ml (4.1 ± 0.11, P < 0. 001). According to the results, the nanoparticles used in this study were appropriate at concentrations ≥ 100 μg / ml for cell tracking.

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Wheat (Triticum aestivum L.), as one of the most important cultivated crops in the world and Iran, is constantly threatened by many diseases, including Fusarium contamination. Due to the unique characteristics of nanoparticles, copper oxide nanoparticles show high antibacterial and antifungal properties. The purpose of this research was to comparatively investigate the antifungal effects of copper oxide nanoparticles and its bulk form on the suppression of Fusarium calmorum in wheat. For this purpose, a pot experiment was done with four levels (10, 250, 500, and 1000 mg L^-1) of nanoparticles and bulk form of copper oxide treatments in wheat (Roshan cultivar). The results showed that the maximum inhibition of root pathogenicity was observed in a high concentration of nanoparticles as compared to bulk form. The 250 and 500 mg L^-1 concentrations of copper oxide nanoparticles caused the highest stem and root length and the highest dry weight of the aerial part and root, respectively. Treatment with 10 and 250 mg L^-1 nanoparticles also increased the content of chlorophyll a, total chlorophyll, carotenoid, chlorophyll stability index, membrane stability coefficient, and relative leaf water content. While the content of chlorophyll b, malondialdehyde, hydrogen peroxide, and proline increased with the increasing concentration of both nanoparticle and bulk forms. The results of this research showed that the low and medium concentrations of nanoparticles were more successful in inhibiting the aforementioned fungus than the bulk form.