Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Environmental Factors Influencing Bacterial Biofilm Formation and Inactivation(Izmir Institute of Technology, 2020) Üreğen, Mert; Özçivici, Engin; Baysal, Ayşe Handan; Baysal, Ayşe Handan; Özçivici, Engin; 03.01. Department of Bioengineering; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyObjective of this study was to evaluate effect of UV-C radiation (0, 1.16 and 3.21 kJ/cm2), pomegranate (Punica granatum) seed essential oil (PGEO) and lemon (Citrus lemonum) plant essential oil (CLEO) on decontamination of Candida albicans, Listeria monocytogenes, Staphylococcus aureus and Esherichia coli O157:H7 biofilms formed at +4°C and 20°C on polystyrene, stainless steel and glass surfaces. After 16, 32 and 64 sec UV-C treatment 0.24 log CFU/cm2, 1.61 log CFU/cm2, 1.59 log CFU/cm2 reductions were achieved in the numbers of C. albicans biofilms formed at 20°C on polystyrene. In the numbers of S. aureus biofilms formed at 20°C on polystyrene 0.99 log CFU/cm2, 1.9 log CFU/cm2, 3.91 log CFU/cm2 reductions were obtained after 16, 32 and 64 sec UV-C treatments, respectively. In general C. albicans biofilm formed at 20°C on stainless steel was found as the most UV-C resistant biofilm. CLEO inhibited the growth of C. albicans, L. monocytogenes and S. aureus at MIC values of 186 µg/ml, 103.5 µg/ml and 103.5 µg/ml, respectively. The results of the study showed that UV-C radiation and CLEO can be used as an anti-biofilm agent to control or to prevent biofilm formation of foodborne bacterial pathogens. It was suggested that UV-C radiation and CLEO treatments have potential as a biofilm control interventions for the food industry.Master Thesis Biochemical and Molecular Characterization of Extracellular Enzyme Producing Staphylococci Isolated From Different Origins(Izmir Institute of Technology, 2006) Appak, Sıla; Güneş, Hatice; Güneş, Hatice; 04.03. Department of Molecular Biology and Genetics; 04. Faculty of Science; 01. Izmir Institute of TechnologyStaphylococci are pathogenic bacteria known to cause diseases among diferrent organisms including human. The two species Staphylococcus aureus and Staphylococcus epidermidis are well defined in human diseases although their exact mechanism of pathogenesis is still not fully understood. These pathogenic bacteria could be isolated from soil, water, air, as well as from the living organisms and they are both pathogenic and saprophytic.Extracellular enzymes of the organisms are used for the industrial purposes. The isolation and characterization of these enzymes are crucial steps in biotechnology. The extracellular enzymes derived from the bacteria serve for many purposes in the industry. In this project 128 Staphylococcus sp. were used. Of these 128 bacteria, 12 were isolated from patients, 40 were isolated from the foodhandler.s hygiene detections, 27 were isolated from pygeons and 49 of them were reference strains. They were searched for the presence of some of the industrially important extracellular enzymes: protease, lipase, cellulase, xylanase, amylase, laccase, urease, DNase and pectinase with biochemical tests. They were also searched for the presence of the lipase, protease and thermonuclease amplifications by PCR. The bacteria apart from the refence strains were also tried to be identified by 16S-ITS-rRNA RFLP analysis. The results would indicate the extracellular enzyme production among these pathogenic bacteria and would also be used as a guide in further studies to correlate between Staphylococcal pathogenity and enzyme production.