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Due to the wide applications of gold nanoparticles, there have been great demands for their synthesis recently. Chemical methods produce pure and Non-dispersive nanoparticles, but these are quite expensive and potentially toxic to the environment. It has been suggested that the use of biological organisms and their components could be a suitable alternative for the production of nanoparticle in an eco-friendly manner (green synthesis). Using plant extracts for nanoparticle synthesis can be advantageous over other biological processes because it eliminates the elaborate process of maintaining cell cultures and can also be suitably scaled up for large-scale synthesis. In this study leaf extracts of Water cress, were used for green synthesis of gold nanoparticles. Gold nanoparticles were formed by treating an aqueous HAuCl4 solution by different amount of plant leaf extract as reducing agent at different temperatures. UV–visible spectroscopy was used for monitoring of the reaction progress. The synthesized gold nanoparticles were characterized with Dynamic light scattering (DLS) size analyzer, Transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The results show that only a few minutes were required for the synthesis of gold nanoparticles at 60 °C and 80 °C by 1000 μl of plant extract, suggesting appropriate reaction rates in comparable to those of nanoparticle synthesis by chemical methods. TEM images showed that spherical nanoparticles (size, 10–50 nm) were obtained at higher temperatures and leaf broth concentrations. The analysis of FTIR bands show that the Polysaccharides and proteins are probably involved in the bio reduction and synthesis of nanoparticles.

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Objectives: Tissue homeostasis is the result of strict regulatory mechanisms, which control self-renewal, differentiation, prevention of premature senescence and apoptosis of stem cells. Bmi-1, a Polycomb group repressor protein, represses genes that induce cellular senescence and cell death, and can contribute to cancer when improperly expressed. Material and methods: Bladder tumoral and nontumoral samples were collected from Labbafi-Nejad hospital. RNA was extracted from each sample, reverse transcribed and amplified by RT-PCR technique, using specific primers for Bmi-1 and β2-microglobolin, as an internal control. The production and distribution of Bmi-1 protein was also examined by western blotting and immunohistochemistry technique. Results: To clarify the role of Bmi-1 in bladder tumors, we examined the expression of Bmi-1 in tumoral and nontumoral samples. RT-PCR generated a 683 bp product, corresponding to the expected size of the Bmi-1 amplified region. The identity of the amplified fragment was then confirmed by direct DNA sequencing. The mean of expression of the Bmi-1 detected in tumoral tissues was significantly higher than the non-tumoral tissues and there is also a significant correlation between the mean of gene expression with stage of malignancy (p < 0.05). The expression of Bmi-1 at protein level was further confirmed by western blotting and immunohistochemistry. Conclusion: The tumor suppressor locus Cdkn2a (Ink4a/Arf locus) codes for two proteins, p16ink4a and p14arf. Ink4a and Arf are playing important roles in the retinoblastoma (pRB) and p53 pathways, respectively. Bmi-1 is a potent repressor of both pathways and hence elucidating its role in tumorigenisis is very important. Here, for the first time we are reporting the expression of Bmi-1 and its correlation with malignancy in bladder tumors.