Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/5799
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Master Thesis Tasarlanmış Mikroorganizmalar ile Katma Değeri Yüksek Karotenoidlerin Biyosentezi(Abdullah Gül Üniversitesi, Fen Bilimleri Enstitüsü, 2024) Arslansoy, Nuriye; Fidan, ÖzkanCarotenoids are pigment molecules that play an important role in coloring plants, algae, and other organisms. These molecules exhibit various biological activities such as anticancer, antiviral and antioxidant activities. They have a huge market size and are mainly used in the food, feed, and cosmetic industries. The current supply chain for carotenoids is mostly relied on the extraction from plants and/or chemical synthesis for certain carotenoids. However, these strategies have various bottlenecks and disadvantages such as being affected by climate change, more difficult and costly extraction processes, and environmental issues. These can be overcome with microbial biosynthesis, which not only addresses the previous problems but also provides advantages of producing in a short time and scale-up for industrial production. In this research, we aimed to biosynthesize the high value-added carotenoids by engineered microorganisms. The genome of a native producer of zeaxanthin diglucoside, identified as endophytic Pseudomonas sp. 102515, was first edited by CRISPR-Cas9 to knock out zeaxanthin glucosyltransferase (CrtX), lycopene β-cyclase (CrtY) and beta-carotene hydroxylase (CrtZ). This led to ΔcrtX, ΔcrtY and ΔcrtZ mutant strains of Pseudomonas sp. 102515. On the other hand, overexpression plasmids carrying crtW, CaZEP and CaZEP-CaCCSm40 genes were constructed and transformed to ΔcrtX mutant to synthesize astaxanthin, violaxanthin and capsanthin/capsorubin. HPLC analysis of extracts from mutant strains and overexpression strains revealed that all the engineered strains produced the corresponding carotenoids such as zeaxanthin, β-carotene, and lycopene. Thus, this study paved the way for the biosynthesis of valuable carotenoids in the engineered endophytic bacteria.Master Thesis Nanokristal Kuantum Nokta Filmler ile Escherichia Coli Arasındaki Etkileşimin İncelenmesi(Abdullah Gül Üniversitesi, Fen Bilimleri Enstitüsü, 2017) Ünlü, Miray; Mutlugün, EvrenSemiconductor nanocrytals also known as quantum dots (QD) with high photoluminesce quantum yield (PLQY), size tunability and favorable optical characteristics occupy a significant area in display technology, solar energy conversion and biotechnology. Size tuning feature of QDs allows peak emission wavelength ranging from ultraviolet to infrared spectral region. In literature, QD based studies have been performed in visible spectral range by employing mostly cadmium, being a toxic heavy metal. Recently, the search for less toxic alternatives revealed the cadmium free compounds, particularly InP. Cadmium free semiconductor nanocrytals' potential to be used as fluorescent probes in biodetection and biolabeling area has been proved over the past decades. Pathogens threaten life particularly via water sources like rivers, reservoirs and groundwater. Increasing demand for managing the 'contamination of drinkable water by pathogenic bacteria' problem needs a broad perspective about pathogens and their membrane characteristics which are integral part of microorganism detection platforms. Bacteria are categorized mainly upon their membrane properties which are gram negative and gram positive. Extra wall called as peptidoglycan layer in gram positive bacteria makes them more resistant to external forces. Gram negative bacteria with wavy wall is relatively more prone to their environment. One of the most known pathogenic bacteria, E. Coli, have damaged and destroyed many lives throughout the world. High growth rate enables this microorganism to spread around large areas in short time. Therefore, accurate and definite detection of this bacteria in water is crucial. The main frame of this research depends on QD based biodetection of bacteria. First of all, organic based QDs (50% PLQY) containing triocytlyphosphine-sulfur ligand were synthesized and via successful phase transfer, QDs in aqueous solvent with 20% PLQY were achieved. Although surface is damaged during ligand exchange procedure, QDs in aqueous solvent with high PLQY were obtained. SiO2 was covered with QDs thanks to the attraction between their NH2 group and carboxylic ends, respectively. In the final step, this hybrid structure was encapsulated with SiO2 and silica coated QDs (SCQD) were formed. In order to utilize SCQDs in bacteria detection, fluorescent agents were embeded in polymeric films which were formed by spin coating. As a result, SCQD facilitates the attachment of negatively charged bacteria onto the surface of the films. Appropriately grown DH5 alpha (E. Coli strain) expressing green fluorescent protein (GFP) was used as pathogen in the detection part. SCQD thin films were treated with water containing E.Coli DH5 alpha. Positively charged SCQD attracted negatively charged bacteria and the conjugation between them was analysed with time resolved spectroscopy and monitored with fluorescence microscope. Thus, usage of QDs as biosensor in pathogen detection could provide an insight in the future studies. Keywords: biodetection, E.coli, quantum dots, semiconductors, silica coated quantum dots, indium phosphate, InP QDMaster Thesis Cisplatin Temelli Nefrotoksisite Karşıtı Böbrek Hedefli Bir Nanotaşıyıcı Formülasyonu Geliştirilmesi(Abdullah Gül Üniversitesi, Fen Bilimleri Enstitüsü, 2019) Çakır, Şerife; Aydın, ErkinKitosan doğal bir polimer olup diğer sentetik polimerlere oranla vücutta daha az toksik etki göstermektedir. İyonik jelasyon metodu ile üretilen kitosan sodyum tripolifosfat (TPP) nanopartiküllerin böbrek ve beyin dokusu gibi insan vücut dokuları için iyi bir ilaç salınım araçları olduğu bilinmektedir. Bu çalışmada bir anti-kanser ilacı olan cisplatinin böbreklere oluşturduğu nefrotoksisiteyi gidermek için, gen susturucu siRNA'larla yüklü kitozan-TPP nanoparçacıkları kullanılmıştır. In vitro çalışmalar human kidney cell line olan Hek293 hücrelerinde denenmiş olup nanoparçacıkların hücreye girişleri ise floresan mikroskobu ve flow sitometri ile doğrulanmıştır. MTT ve XTT sonuçlarına göre nanoparçacıkların toksik etkisi düşük bulunmuştur. In vivo çalışmalara bakıldığında ise, balb-c tip 6-8 haftalık farelere siRNA yüklü nanoparçacık enjeksiyonu yapılmıştır. Sisplatin ile muamele edilmiş fareler kontrol ve siRNA-yüklü kitosan nanopartiküller grubu olarak hayvan grupları kullanılmıştır. Sisplatin enjeksiyonlarından sonra, siRNA-nanopartükül verilmesinden sonra farelerdeki kreatinin ve BUN seviyeleri değişimi incelendi. GAPDH bir kontrol geni olup PKC, P53, OCT1, OCT2 ve GGT genleri böbrek proximal tübül hücrelerinde önemli rollere sahiptir. Bu çalışmada bu genlerin mRNA seviyelerine de kantitatif PCR ile bakılmıştır. Enjeksiyonun ilk günlerinde siRNA'lar azalmış iken devam eden günlerde bu etki kaybolmuştur. Böylelikle her siRNA'nın susturma potansiyeli değişkenlik göstermektedir. Fakat bu değişkenlik çalışmada anlamlı bir değişim göstermektedir.