Master Degree / Yüksek Lisans Tezleri

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Access Right: Open AccessSubject: search.filters.subject.Saccharomyces cerevisiae

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  • Master Thesis
    Developing a Guide of Bioinformatic Database for Probiotic Products
    (Izmir Institute of Technology, 2019) Yılmaz, Melike; Sezgin, Efe; Harsa, Hayriye Şebnem; Harsa, Hayriye Şebnem; Sezgin, Efe; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Recently, probiotic use has rapidly expanded, as they have potential health effects for microbiota to protect homeostasis in the human body. Bioinformatics is generally defined as collecting and analysing biological data. Establishing a bioinformatic system for probiotics, would have a potential to emphasize the beneficial impacts for human health, while enabling cross examination on diseases and products. In this study, new information has been collected about probiotics based on in vitro, in vivo, clinical trials and meta-analysis to develop a comprehensive guide. Metaanalyses of sixteen and seventeen randomized, controlled trials of S. boulardii (Sb) against diarrhea reported pooled relative risks of 0.51 (95% CI [0.40-0.64]) in adults and 0.55 (95% CI [0.42-0.72]) in children, respectively. These results demonstrated that Sb was effective for preventing and treating different types of diarrhea in adult and children patients. An in silico gene expression study conducted in Tecnico Lisboa* comparing Sb probiotic and non-probiotic Saccharomyces cerevisiae (Sc) strains showed transcription regulation differences in 26 genes. An in silico pipeline that was used as the basis for a new query in the ProBioYeastract database was developed. A cross-strain promoter analysis, comparing Sb CNCM I-745 and Unique28 strains with Sc S288C strain showed that the expression of 26 probiotic-related genes was predicted to be controlled by different transcription factors in probiotic vs non-probiotic strains. Among the evaluated six selected genes, a gene involved in biofilm formation, aggregation, and adhesion, EFG1, was found to be up-regulated in Sb CNCM I-745 compared to Sc BY4741.
  • Master Thesis
    Elucidation of Molecular Mechanisms Conferring Arsenic Tolerance To Yeast Cells
    (Izmir Institute of Technology, 2016) Işık, Esin; Karakaya, Hüseyin Çağlar; Karakaya, Hüseyin Çağlar; 04.03. Department of Molecular Biology and Genetics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Arsenic is a highly toxic metalloid available in the environment mainly as arsenite or arsenate. These compounds’ interference with many molecular mechanisms results in several diseases including cancer. Conversely, arsenic is used in therapeutic approaches, however, they are associated with drug resistance. Although some tolerance and toxicity mechanisms of arsenicals in yeast have been enlightened by previous studies, complete understanding, which is important for development of protection and therapy strategies, has not yet been achieved. Comprehensive genome-wide screening is a promising approach for the elucidation of novel genes involved in arsenic-associated mechanisms. The aim in this study was to screen a yeast genome library to characterize novel genes whose overexpression confers resistance to toxic concentrations of arsenate or arsenite in Saccharomyces cerevisiae. The plasmids from the colonies confirmed to be highly-resistant against arsenicals were sequenced to determine the genomic regions and seven genes were selected to clone into expression vectors. The overexpression of Pho86p and Vba3p provided yeast cells with the highest arsenate and arsenite resistance, respectively. Arsenate is a phosphate analogue and taken up by phosphate transporters. Pho86p is an ER-resident protein regulating ER-exit of the phosphate transporter. Therefore, it is reasonable that overexpression of Pho86p provides arsenate resistance. Vacuolar sequestration is a common route for the removal of toxic compounds from the cytosol and Vba3p is a vacuole-located transporter of basic amino acids with a likely role in arsenite resistance. Consequently, the screen in the current study revealed two genes with promising roles for tolerance mechanisms against arsenicals.