Baker's Yeast Lab Report

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3.1. Green photosynthesis of gold nanoparticles using aqueous extract of Baker’s yeast:
One aim of the present study is the development of an improved method for derivatization of metabolites existed in aqueous extract of Baker’s yeast (Saccharomyces cerevisiae). This procedure facilitates identification of metabolites in Baker’s yeast extract and its utility for the synthesis of nanomaterials. The preparation of trimethylsilylenol ethers of metabolites was performed by treatment of the extract with catalytic amounts of trimethylsilylchloride (TMSCl) and trimethylsilylimidazole to produce silylated compounds that were determined using gas chromatography mass spectroscopy. The GC/MS analysis of the culture supernatants of aqueous extract of
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AuCl3) were added to the aqueous Baker’s yeast extract and then allowed to react under visible light for 30 minutes, it was observed that Au ions were reduced extracellularly to gold nanoparticles (figure 4). Au nanoparticles with uniform size distribution 13.0±0.9nm and plasmon band λ=~535nm are formed.
The crystalline nature of biosynthesized gold/yeast nanoparticles was further confirmed from XRD analysis. The XRD patterns of the photo-biosynthesized gold nanoparticles are shown in figure 5. The four intense diffraction peaks were observed at 2Ө values of 38.30°, 44.43°, 64.67°, and 77.67°, corresponding to the (111), (200), (220), and (311) reflection of the crystalline metallic gold, respectively.
In our photo reduction study, photosensitization of butane-2,3-diol and indole-3-acetic acid can be carried out (35). The yeast extract solution under visible light act as reducing and capping agents. The reduction of noble metal ions to nanoparticles catalyzed through oxidation of glucose to gluconic acid by providing electrons (36, 37). The formed nanoparticles can be also stabilized by the presence of Van der Waals forces between the negatively charged oxygen groups present in the molecular structure of the butane-2,3-diol or indole-3-acetic acid, and the positively charged groups that surround the surface of NPs(34)(see scheme
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Our results are in agreement with Ghoneum et al.(38) results, which showed that at the ratio of cancer cells to yeast (1 : 10) induced 21.4 % of dead cancer cells by making phagocytosis of yeast into the cancer cell and thereby induction of cancer cell apoptosis in a caspase independent mechanism. Earlier studies have been shown that breast cancer cells (BCCs) in a culture can phagocyte latex beads and fluorescent Matrigel. That study has confirmed the phagocytic activity by BCCs when using yeast as a test organism (40). The results of this study were demonstrated that phagocytosis of heat-killed Baker 's yeast induces apoptosis in the highly metastatic cells (MCF-7 and ZR-75-1) and in the non-metastatic cells (HCC70) in a caspase-independent mechanism. Moreover, this observation may have therapeutic implication. It was approved that the apoptosis of cancerous cells by heat killed Baker 's yeast is caspase-independent manner and reactive oxygen intermediate (ROI) - independent (38), and showed that phagocytosis of yeast lead to the disruption of the mitochondrial membrane potential. Therefore, it was suggested that the release of some or all of the other

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