Theses (Faculty of Science and Technology)
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Theses collection of the XX department/institute. The collection was started in 2017.
At the University of Debrecen, in accordance with the 2022 amendment to the 2011 Higher Education Act, student theses are only accessible from devices connected to the University's Eduroam WiFi network or from a university IP address.
“The thesis or diploma work of a student who has successfully passed the final examination shall be stored in full in the academic system of the higher education institution, and a record shall be maintained thereof. The stored theses and diploma works – with the exception of parts classified as confidential in accordance with the relevant legislation – must be made accessible and searchable without restriction through the academic system.” Further info on the National Higher Education Act in Hungarian: Felsőokt. tv. (új) - 2011. évi CCIV. törvény a nemzeti felsőoktatásról - Hatályos Jogszabályok Gyűjteménye.
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Tétel Korlátozottan hozzáférhető Phylogenetics and Diversity of Traditional Farmhouse Ale MicrobiotaAzganov, Timur; Pfliegler, Valter; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThe traditional brewing of farmhouse ales, particularly in regions like Norway and Lithuania, represents a unique intersection of cultural heritage and microbiological diversity. This study delves into the genomic landscape of Saccharomyces cerevisiae strains isolated from these ales, focusing on their phylogenetic relationships and potential evolutionary pathways. The Lithuanian yeast strains analyzed displayed distinct genetic markers suggesting a mixed ancestry with Asian fermentation yeasts, likely influenced by historical trading routes such as the Silk Road. Parallel to this, the bacterial species present in the fermentation process were investigated, revealing a broader microbial diversity than previously documented. These findings show the complexity of traditional ale fermentation, highlighting the need for further exploration into the microbial interactions that shape the flavor profiles traditional beverages.Tétel Korlátozottan hozzáférhető What is the prevalence of killer and resistant phenotypes among clinical isolates?Mir, Sheezan Shafi; Pfliegler, Valter Péter; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThis thesis examines the prevalence of killer and resistant phenotypes in yeast strains against K1 and K2 toxins. Testing 13 strains revealed varying resistance levels, with some strains showing high resilience, suitable for probiotic and industrial use. These insights help in selecting effective yeasts for applications in food, health, and animal husbandry.Tétel Korlátozottan hozzáférhető Applying Machine Learning for VCF file filteringAllouh, Fares Raja Farah; Pfliegler, Valter Péter; Németh, Bálint; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetAn in silico experiment in which the sequencing data of chromosome 1 from a multitude of S. cerevisiae strains was utilized. The compendium of yeasts created by the Department of Molecular Biotechnology and Microbiology provided the data for many S. cerevisiae strains and their different sequencing runs (replicates). Variants from same-strain replicates were called and combined into VCF files which were then subjected to hard-filtering, and filtering by a convolutional neural network. The study describes a pipeline which utilizes the Genome Analysis Toolkit (GATK) for variant calling and filtration. Finally, the efficacies of both methods are compared, and their strengths and weaknesses are highlighted.Tétel Korlátozottan hozzáférhető Unlocking Citric Acid Potential: The Impact of Manganese (II) Levels in Aspergillus niger Fermentation ProductionAwwad, Agadi; Vivien, Bíró; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThis thesis investigates the production of citric acid through the fermentation of Aspergillus niger, with a focus on optimizing conditions to improve yield, efficiency, and environmental sustainability. The study explores the biological and metabolic mechanisms of Aspergillus niger in citric acid synthesis, examining how parameters like pH, temperature, and nutrient availability influence productivity. A special emphasis is placed on manganese (Mn) regulation, analyzing its impact on enzyme activity and citric acid output. The research also evaluates cost-effective substrates and eco-friendly practices, aiming to make citric acid production more sustainable. Ultimately, this work contributes valuable insights into optimizing microbial fermentation processes for industrial applications.Tétel Korlátozottan hozzáférhető Allogeneic reactions of pre-activated CAR T cells on target-negative cancer cellsLi, Artyom; Nagy, Lőrinc; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetT cells were isolated from 2 donor's PBMCs and transduced with HER2-CAR construct. The study evaluated the cytotoxic activity of HER2-CAR T cells against three cell lines: HER2-negative MDA cells and HER2-positive MDA-HER2 and MDA-HER2-231 cells. The results demonstrated significant cytotoxicity against MDA-HER2 cells, confirming the specificity of HER2-CAR T cells, while no cytotoxic effects were observed for HER2-negative MDA cells and MDA-HER2-231 cells, which had low expression of HER2 antigen. It implies that HER2-CAR T cells are unlikely to target healthy tissues with low expression of HER2. The same pattern was observed in the case of pre-activated T cells, and regardless of IL-2 and the donor of T cells.Tétel Korlátozottan hozzáférhető Synthesis and Microwave-Assisted Pathways of 6-Iodo- Benzoflavanone DerivativesEmara, Fatma; Kurtán, Tibor; DE--Természettudományi és Technológiai Kar--Kémiai IntézetMy thesis explores the synthesis of 6-iodo-4’-(trifluoromethyl)-7,8-benzoflavanone, focusing on its potential as aromatase inhibitor to aid in breast cancer treatment. The thesis outlines two synthetic pathways: microwave-assisted and base-catalyzed, each employing multiple reaction steps to optimize yields and reaction efficiency. Starting from hydroxyacetophenone derivatives, the synthetic process includes key steps like Friedel-Crafts acylation, Claisen-Schmidt condensation, and cyclization, achieving varying yields across methods, structures were confirmed using NMR spectroscopy. The study emphasizes the microwave-assisted approach for its efficiency and reduced reaction time, aligning with green chemistry principles. Ultimately, the synthesized benzoflavanone derivatives serve as standards for stereoselective reactions, with successful enantioselectivity applications promising for drug development.Tétel Korlátozottan hozzáférhető Genomics of lesser-known groups of Saccharomyces cerevisiaeBujupaj, Arditë; Pfliegler, Valter Péter; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThis thesis focuses on the Saccharomyces cerevisiae strains that are lesser known scientifically, yet their contribution to industries such as whisky production are enormous. Samples of distillery yeasts in Hungary were sequenced, and analyzed. In addition, genomic data of more than 20 other S. cerevisiae distillery strains got analyzed using multiple bioinformatics software and data analysis principles in Linux environment. Those yeasts were placed in the phylogenomic tree of species and visualized to determine if any distillery yeast brands are identical or whether there is any hybrid. Moreover, their ploidy got assessed. Results reveal that the sequencing was successful and gives new insights into the nature of these species. It got discovered that some of the yeasts belong to lager beer and vodka/bioethanol-producing species, and several of these yeasts are hybrids of 2 different Saccharomyces species. Most of the yeasts got noticed to be diploid.Tétel Korlátozottan hozzáférhető Synthesis of ruthenium half-sandwich type complexes with C-glycosyl-formaldehyde imine ligandsKuantayev, Adilkhan; Juhászné Tóth , Éva; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThe thesis focuses on the synthesis and study of ruthenium half-sandwich complexes with sugar-based ligands, aiming to explore their potential as anticancer agents. Glycomimetics, which are synthetic sugar analogs, play a crucial role in mimicking biological processes and overcoming the limitations of natural glycans in drug development. Using advanced synthetic methods, several ruthenium complexes were successfully prepared and characterized with techniques like NMR and mass spectrometry. These complexes showed promise due to their structural stability and potential biological activity. The study contributes valuable insights into the design of multitargeted metallodrugs. The research lays the groundwork for developing safer and more effective therapies for cancer and possibly antimicrobial applications.Tétel Korlátozottan hozzáférhető Analysis of the microbial composition of Hungarian sourdoughs with next generation sequencingBazenova, Rizagul; Pfliegler, Valter Péter; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetIn the breadmaking industry, sourdough represents a special microenvironment where lactic acid and other bacteria and yeasts (mainly Saccharomyces cerevisiae) coexist, each contributing to the formation of a dynamic microbial community. Their cohabitation ensures the unique properties that have been exploited in the process of bread preparation for centuries. Analysis of sourdough samples from different regions provides insight into the origin and uniqueness of microbes that are found in local sourdough starters. Moreover, an investigation of those microbial communities and their genomic properties provides particular information on how these microbes coexist and evolve. With the help of next-generation sequencing technologies, such as Oxford Nanopore’s long-read-based metagenomics/metabarcoding and whole genome sequencing solutions, we were able to gather information about various Hungarian sourdough samples. To our knowledge, we are the first to analyze the bacterial and yeast community from local sourdoughs of the country along with a detailed phylogenomic analysis of S. cerevisiae isolates found in them.Tétel Korlátozottan hozzáférhető "Evaluating Novel Bacteriophage for Stenotrophomonas maltophilia Disinfection: Stability and Efficacy in Environmental Conditions"Hafeez, Sidra; Freytag, Csongor; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThis thesis investigates the effect of physio-thermal conditions on the stability of Novel bacteriophages isolated against Stenotrophomonas maltophiliaTétel Korlátozottan hozzáférhető Gelatin and crosslinked gelatin aerogels : synthesis and characterizationRanga, Andreea; Forgács , Attila; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThis study focuses on the synthesis and characterization of gelatin-based aerogels with optimized properties for advanced applications. Gelatin was used as the base material, with synthesis conditions refined by adjusting parameters such as gelatin sheet size, stirring rate, temperature, and gelation time. Solvent exchange with methanol was employed to minimize structural deformation, followed by supercritical drying at 40°C to produce uniform aerogels. Three aerogels (RM20, RM24, RM29) were synthesized with varying degrees of crosslinking using glutaraldehyde (GTA) to evaluate the effects of crosslinking on their structure and properties. Characterization included SEM imaging, N₂ porosimetry, mechanical testing, and swelling behavior analysis under different pH conditions.Tétel Korlátozottan hozzáférhető Effects of Mn²⁺ Ions on Aspergillus terreus for the Production of Itaconic AcidSaleh, Hana; Bíró, Vivien; Márton, Alexandra; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetThis thesis investigates the optimized production of itaconic acid using Aspergillus terreus, focusing on the impact of manganese (Mn²⁺) on yield. Itaconic acid, a sustainable alternative to petrochemical products, is used in plastics, resins, and biofuels. The study examines key fermentation parameters, including pH, temperature, and aeration, to maximize yield while controlling Dry Cell Weight (DCW). Findings reveal that manganese concentration significantly affects production, providing strategies to enhance industrial-scale yields. The research also highlights the potential impact of manganese leaching from bioreactors in industrial settings.Tétel Korlátozottan hozzáférhető Synthesis and structural determination of co-crystals of FurosemideErasga, Adlai Steven; Attila, Bényei; DE--Természettudományi és Technológiai Kar--Kémiai IntézetChanging the structure of the unit cell of a crystal will change its properties and for co-crystals, this change is done by adding a new molecule into the unit cell. This change in structure helps produce crystals with specific properties and this has various applications like the pharmaceutical industry. Within this thesis, co-crystals are made from a loop diuretic, Furosemide, with the aims to study the structural changes and increase solubility. Furosemide is mixed with 3 co-formers: picolinic acid (pyridine-2-carboxylic acid), nicotinic acid (pyridine-3-carboxylic acid), and isonicotinic acid (pyridine-4-carboxylic acid). The produced crystals were then measured using different x-ray diffraction techniques to both prove the presence of a co-crystal as well to completely map out the unit cell of the crystal.Tétel Korlátozottan hozzáférhető Investigating genotypic and phenotypic characteristics of commercial mead yeastsToxeitova, Aizhan; Pfliegler, Valter; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetMead is a traditional fermented beverage which is created from diluted honey by yeasts, such as Saccharomyces cerevisiae, yielding an ethanol content of 8% to 18% (v/v). However, mead yeast genomes remain largely unexplored, with few genomes available from traditional Ethiopian honey wines and none from Europe. This study aims to analyze 13 commercially available mead yeast strains from prevalent mead-producing regions such as US, UK, Sweden, Poland, and Czech Republic. We employed phenotyping and genomics to evaluate their colony morphology, invasivity, sporulation, flocullence, high glucose, and temperature tolerance. The research findings elucidate the origins and relationships of mead yeasts within different yeast subgroups.Tétel Korlátozottan hozzáférhető Micropropagation as a plant preservation techniqueSambayeva, Aliya; Máthé, Csaba; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetMicropropagation is widely used to preserve disease-free plants in the axenic environment. Micropropagation is used in different fields such as food industry, pharmacy, and commerce. It is also utilized in the University of Debrecen, Faculty of Science and Technology, Department of Botany. This paper discusses the theoretical background, advantages and limitations, and applications of micropropagation. The practical part of the thesis work focuses on the micropropagation of different plant species present in plant tissue bank.Tétel Korlátozottan hozzáférhető The Fragmentation of Phytocannabinoids with a Focus on Cannabigerol and its DerivativesSoares Rodrigues, Gabriel Augusto; Nagy, Lajos; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThe Fragmentation of Phytocannabinoids with a Focus on Cannabigerol and its Derivatives, investigates the structural analysis of CBG derivatives using mass spectrometry. It explores the ionization of compounds through both atmospheric pressure chemical ionization (APCI) and electron spray ionization (ESI), focusing on their fragmentation patterns and stability under different energy levels. The results confirm that the expected mass-to-charge ratios align closely with experimental data, validating the sample structures. The study highlights the characteristic fragmentation of the oxazin ring in all samples, showing that certain side chains are prone to cleavage. This research provides insights into the potential modifications that could enhance the stability and pharmaceutical viability of CBG derivatives.Tétel Embargó alatt Role of the bZIP-type transcription factor AflAtfD in the coordination of oxidative stress defense and aflatoxin production in Aspergillus flavusKHAN, MUHAMMAD UMAIR KAMAL; Leiter, Eva Julianna; DE--Természettudományi és Technológiai Kar--Biotechnológiai IntézetRole of the bZIP-type transcription factor AflAtfD in the coordination of oxidative stress defense and aflatoxin production in Aspergillus flavusTétel Korlátozottan hozzáférhető Fragmentation of the oligopeptides to prove their structures and identify product ions formedShi, Yiran; Nagy, Lajos; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThe structure and fragmentation patterns of oligopeptides were studied in this paper, specifically tau (91-97) and tau (401-409), along with some modifications. Such modification is applied to the oligopeptides to prevent some side reactions. Tandem mass spectrometry (MS/MS) is utilized to prove the structures of these tau peptides and identify the product ions formed during the fragmentation. Although there are some limitations, since the sequence of the oligopeptides were not fully determined, the majority sequence of amino acids was, however, still successfully identified. This study aims to provide a deeper understanding of the biological role of tau peptides and its isomers, which would contribute to the prevention and treatment of neurodegenerative diseases, such as Alzheimer's disease.Tétel Korlátozottan hozzáférhető The comparison of Value at Risk, Expected Short-fall, and Gini measure and its applicationsAlhalibi, Yassin; József, Gáll; DE--Természettudományi és Technológiai Kar--Matematikai IntézetThis thesis studies some of the most used risk measures - Value at Risk (VaR), Expected Short-fall(ES), and Gini measure and their applications. The most often used risk indicator in financial risk management is Value at risk. However, VaR will have some flaws when it comes to measuring extreme risks.Tétel Korlátozottan hozzáférhető Synthesis and characterization of a Mn(II)-based Magnetic Resonance Imaging(MRI) contrast agent candidate derived from pyclenAnsari , Arman Ahmad; Gyula, Tircsó; István, Kapus; DE--Természettudományi és Technológiai Kar--Kémiai IntézetMRI is one of the best-known and most widely used imaging techniques in modern medicine, and its popularity is due to its non-invasive and non-destructive features. Since the 1980s, Gd(III)-based contrast agents have been market leaders, but in recent years, confidence has been shaken by the toxicity of the released gadolinium(III) ions. The essential nature of metal ions is applied to replace Gd(III)-ions in most cases (represented by Mn2+). For manganese complexation, the ligand O2PC6OX was designed and synthesized, and its Mn(II) complex was investigated in order to evaluate its thermodynamic, kinetic, and relaxometric features, with the goal of obtaining a Mn(II) complex with improved physico-chemical parameters.