TY - THES A1 - Schages, Jan T1 - Untersuchungen zum Einfluss mikrobiologischer und technischer Parameter auf die hygienische Qualität von Kaffee aus Kaffeevollautomaten N2 - Der Konsum von Kaffee und seinen Zubereitungsarten hat in den letzten Jahren enorm zugenommen. Die sog. „Kaffee to go“-Getränke gewinnen hierbei immer mehr an Bedeutung und mit den Verpackungen dieser geht eine große Abfallproblematik einher. Der Großteil der Mitnahmegetränke wird in Vollautomaten hergestellt, welche auch im Haushaltsbereich immer mehr zum Einsatz kommen. Diese Vollautomaten müssen regelmäßig gereinigt und gepflegt werden, da sie sonst als Quelle für Lebensmittel-Kontaminationen fungieren können. Durch eine feuchte Umgebung in den Wassertanks und wasserführenden Systemen sowie eine ausreichende Nährstoffzufuhr durch Kaffee und Kaffeerückstände bieten Vollautomaten ein geeignetes Milieu für mikrobielles Wachstum. Um den Einfluss technischer und mikrobiologischer Parameter auf die hygienische Qualität von Kaffee überprüfen zu können, wurden Geräte aus dem Haushalts- und dem gewerblichen Bereich untersucht. Die isolierten Mikroorganismen wurden mittels MALDI-TOF-MS identifiziert und als artifizielle Kontaminationen für weitere Versuche verwendet. Sie dienten als Grundlage für empirische Versuchsreihen und Simulationen an einem Kaffeevollautomaten zum Einfluss der Parameter Temperatur und Zeit auf die mikrobiologische Qualität. Die Wirkung dieser Parameter wurde auch in artifiziell kontaminierten Mehrwegbechern simuliert. Die Ergebnisse zeigen, dass 40 % aller gewerblichen Geräte und 25 % aller Haushaltsgeräte mikrobiologisch belastet waren, die Wassertanks der Haushaltsgeräte waren zu 100 % kontaminiert. Besonders häufig wurden Bakterien der Gattungen Bacillus, Pseudomonas und Staphylococcus identifiziert. Die Ausgabetemperaturen der Vollautomaten sowie die Einwirkdauer der Temperaturen sind als zu gering für eine mikrobiologische Unbedenklichkeit der Lebensmittel einzuordnen. Die Temperaturen der untersuchten Kaffeeproben lagen zwischen 63,59 °C im gewerblichen Bereich und 61,32 °C im Haushaltsbereich. Für kontaminierte Mehrwegbecher konnte eine optimale Kaffeeausgabetemperatur von 68 °C ermittelt werden. Bei adäquater Verwendung geht von Mehrwegbechern kein hygienisches Risiko aus, jedoch von Kaffeevollautomaten bei unzureichender Reinigung. KW - Kaffee KW - Hygiene KW - Mikrobiologie KW - Biofilme Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-1621 ER - TY - THES A1 - Chow, Kan Kau T1 - Comparison of Eight Human Tumour Cell Lines and Their Responses to Low-Dose Reactive Oxygen Species N2 - Cancer as a wide range of life threatening diseases causes over 600,000 death across the US annually. Despite advances in oncology, this exemplifies the need for new avenues in cancer treatment. Tumour cells often display altered susceptibility to reactive species-induced cell death, and changes in redox signalling pathways. Therefore, utilizing reactive species to complement existing therapies may improve therapeutic success. Cold physical plasma is a potent source of reactive species. In this bachelor study, low-dose plasma-generated reactive species and bulk hydrogen peroxide were assessed for their effects on cancer cell growth, morphology, surface marker profile, and transcriptional profile of redox-related target genes. Using eight different cell lines, cell type-specific and non-specific effects were observable. Although the low dose of ROS caused relatively mild effects on altering cell viability and phenotype, it showed significant and specific effects in gene expression, which might be used for further studies utilizing ROS in tumour therapy. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2746 ER - TY - THES A1 - Bartsch, Lisa T1 - Analyse des hygienerelevanten Verbraucherverhaltens im Rahmen der Zubereitung gegrillter Speisen N2 - In den Sommermonaten sind die Zubereitung und der Verzehr von gegrillten Speisen im Freien in deutschen Privathaushalten sehr beliebt. Dabei ist der Zubereitungsprozess beim Grillen aus hygienischer Sicht kaum erforscht. Im Zuge dieser Masterarbeit wurde der gesamte Vor- und Zubereitungsprozess gegrillter Speisen und typischer Beilagen in deutschen Privathaushalten anhand einer Fragebogenerhebung untersucht. Hierdurch konnten kritische Prozessschritte identifiziert werden. Die Auswirkungen dieser kritisch zu bewertenden Prozessschritte auf die Gesundheit der Verbraucher wurden bewertet. KW - Grillen KW - Hygiene KW - Grillen KW - Hygiene Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2638 ER - TY - THES A1 - Swiderek, Paul T1 - Can golf courses help in conserving and improving local biodiversity – a case study at the Elfrather Mühle, Krefeld T1 - Können Golfanlagen helfen lokale Biodiversität zu schützen und zu verbessern – ein Fallbeispiel am Golf und Country Club Elfrather Mühle, Krefeld N2 - Habitat losses by fragmentation, agriculture, urbanization, and other causes have led to significant declines in biodiversity. Thus, green infrastructures like golf courses have emerged as a potential contributor to biodiversity conservation. Therefore, the research focuses on a golf course in Krefeld, Germany, by examining its role in supporting, conserving, and improving local biodiversity. The objectives include assessing the biotopes and habitats provided by the golf course, investigating the potential of an ecosystem analysis to enhance overall biodiversity, and evaluating the golf course's effectiveness in conserving local species of conservation concern. Through landscape analysis, significant differences between the golf course and surrounding areas were observed. The golf course was ascertained to exhibit a significantly higher biotope value compared to other land use systems except natural ones. Woody biotopes, including forests and tree groups, demonstrated the highest on-course biotope values, while short-kept grass, roughs, ponds, and non-native woody structures were less valuable. Theoretical enrichments of meadow-, pond-, and non-native biotopes as well as their relative size indicated potential for improving biotope value to support biodiversity. Combined enrichments were indicated to be the most effective. Despite the current presence of only a few habitat types, the golf course was found to support local fauna and flora species of conservation concern. Adaptations, such as creating meadow-, riparian-, copse-, and forest habitats, showed promise to further improve biodiversity. The study identified landscape context and prior land use as crucial factors influencing golf course’s value. Overall, the golf course demonstrated potential in providing valuable biotopes, and habitats and supporting local and regional species of conservation concern. The findings suggest that golf courses, particularly in urban and suburban areas, can serve as effective contributors to biodiversity conservation by enhancing landscape connectivity and providing essential habitats. Enrichment strategies, coupled with a focus on specific habitat types, offer practical avenues for improving the conservation status of both local and regional flora and fauna species on golf courses. This research underscores the potential of golf courses as valuable tools in urban biodiversity conservation efforts. N2 - Verluste an Lebensräumen durch Fragmentierung, Landwirtschaft, Urbanisierung und andere Ursachen haben zu erheblichen Rückgängen der Artenvielfalt geführt. Dadurch ist das Interesse an grüne Infrastrukturen wie Golfplätzen, als potenzielle Beitragende zum Artenschutz, gestiegen. Daher wurde auf einer Golfanlage in Krefeld (GCC Elfrather Mühle), NRW, indem dessen Rolle bei der Unterstützung, Bewahrung und Verbesserung der lokalen Artenvielfalt untersucht wurde. Die Ziele der Forschung umfassten die Bewertung der Biotope und Lebensräume des Golfplatzes, die Untersuchung des Potenzials einer Ökosystemanalyse zur Verbesserung der Gesamtartenvielfalt und die Bewertung der Effektivität des Golfplatzes bei Bewahrung lokaler planungsrelevanter Arten von Schutzinteresse. Durch eine Landschaftsanalyse wurden signifikante Unterschiede zwischen dem Golfplatz und den umliegenden Gebieten im Raum Krefeld festgestellt. Der Golfplatz wurde im Vergleich zu anderen Landnutzungssystemen, außer natürlichen Ökosystemen, als wesentlich wertvoller eingestuft. Gehölzbiotope, einschließlich Wälder, Kleingehölzen und Baumgruppen, wiesen die höchsten Biotopwerte auf, während sowohl kurz gemähtes Gras der Fairways und Greens, als auch Roughs, Teiche und nicht-heimische Gehölzstrukturen weniger wertvoll waren. Künftige Entwicklungsmaßnahmen wie Anreicherung von Wiesen- und Teichbiotopen durch spezielles Saatgut, die ausschließliche Pflanzung von heimischen Baumarten sowie eine geringe Vergrößerung der Biotope im Vergleich zur Golffläche haben das Potenzial zur Verbesserung des Biotopwerts zur Unterstützung der Artenvielfalt. Kombinierte Aufwertungen wurden als am effektivsten eingestuft. Trotz der gegenwärtigen Existenz weniger unterschiedlicher Lebensraumtypen wurde festgestellt, dass der Golfplatz lokale Fauna- und Flora-Arten von Schutzinteresse unterstützt. Theoretische Aufwertungen wie die Schaffung von Wiesen-, Ufer-, Gehölz- und Waldlebensräumen sowie das Anbringen von Nisthilfen und die Errichtung von Totholzhaufen, konnten als vielversprechende Maßnahme zur weiteren Verbesserung der Artenvielfalt vorgeschlagen werden. Die Studie identifizierte den Landschaftskontext und die vorherige Landnutzung als entscheidende Faktoren, die die Wertigkeit des Golfplatzes beeinflussen. Insgesamt zeigte der Golfplatz Potenzial zur Bereitstellung wertvoller Biotope und Lebensräume zur Unterstützung und Erhaltung lokaler und sogar regionaler planungsrelevanter Arten von Schutzinteresse. Die Ergebnisse legen nahe, dass Golfplätze, insbesondere in städtischen und suburbanen Gebieten, effektive Beiträge zum Artenschutz leisten können, indem sie die Landschaftsvernetzung verbessern und wichtige Lebensräume bereitstellen. Anreicherungsstrategien, mit dem Fokus auf bestimmte Lebensraumtypen, bieten praktikable Möglichkeiten zur Verbesserung des Schutzstatus von lokalen und regionalen Flora- und Fauna-Arten auf Golfplätzen. Diese Forschung unterstreicht das Potenzial von Golfplätzen als wertvolle Instrumente in den Bemühungen zur städtischen Artenvielfaltserhaltung. KW - golf KW - biodiversity KW - conservation KW - landscape connectivity KW - green infrastructure Y1 - 2024 ER - TY - GEN A1 - van Leuven, Nicole A1 - Lucassen, Ralf A1 - Dicks, Anna A1 - Braß, Patrick A1 - Lipski, André A1 - Bockmühl, Dirk T1 - Does antibiotic use contribute to biofilm resistance in sink drains? A case study from four German hospital wards. N2 - As biofilms are known to harbour (multi-)resistant species, their presence in health settings must be considered critical. Although there is evidence that bacteria spread from drains to the outside, there is still a lack of research data focusing on drain biofilms from hospitals. We sampled biofilms from various wards of Helios Hospital Krefeld (Germany), where comprehensive antibiotic consumption data were available. Biofilms were analysed by cell counting, isolation of relevant bacterial groups and genetic and phenotypical resistance parameters. Data were correlated with the prescribed antibiotics of the respective ward. Furthermore, an ex-situ biofilm model was employed to investigate the influence of sub-inhibitory antibiotics on the bacterial community and the prevalence of class 1 integrons. Our results show, that every ward harboured medically relevant bacterial species. While no significant differences were found in cell counts, the median prevalence of the resistance marker gene intI1 correlated with the amount of prescribed antibiotics. In contrast, phenotypical resistances showed no similar tendency. In addition, melting curve analysis data and changes in intI1 prevalence show that the composition of the bacterial community shifted depending on the biofilm and antibiotic. Based on our results we conclude, that sub-inhibitory concentrations of antibiotics have no general effect on biofilms in terms of bacterial community shift and occurrence of antibiotic resistant species. The effect depends on the initial composition of the bacterial community, the antibiotic used and the intrinsic bacterial resistance e.g. prevalence of class 1 integrons. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-20820 ER - TY - THES A1 - Mumtaz, Muhammad Imran T1 - Generation and expression of a mutated murine tRNA-guanine transglycosylase variant N2 - Translation of messenger RNA carrying the nucleic code for protein synthesis is one of the vital bioprocesses of living organisms. This translation is mediated by transfer RNA, which allocates specific amino acids to the growing chain by decoding the genetic code. The tRNAs with the G34U35N36 anticodon sequence are recognised by an enzyme called tRNA-guanine transglycosylase, which catalyses the exchange of guanine with queuine. TGT enzyme is found in all three domains of life and is involved in post-transcriptional modification. TGT is of keen interest in the development of therapeutics against shigellosis, since the genetic inactivation of TGT leads to decreased pathogenicity in Shigella. For understanding the differences between bacterial and eukaryotic TGT, studies have been performed in the past, which show remarkable resemblance. On the contrary, some pronounced structural contrast can also be observed. One prominent difference is that the bacterial TGT contains a short turn of three amino acids, whereas, in eukaryotes, this turn is replaced by an extended loop of more than 45 amino acids. The function of this loop in eukaryotic TGT is not known. The loop is a highly flexible region and, thus, is not structurally solved. To elucidate the function of this loop, a TGT mutant lacking this loop was generated, expressed and purified. TGT mutant was expressed in different bacterial cell strains. For the purification, different chromatography techniques were utilised. The mutation resulted in a low yield of the protein in comparison to the wild-type TGT. This leads to the inference that the loop influences the physicochemical characteristics of the protein. KW - RNA-guanine transglycosylase KW - Generation KW - Expression KW - Queuine KW - Protein purification KW - Chromatography KW - Site-directed mutagenesis KW - Protein mutation Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-18560 ER - TY - THES A1 - Vu, Trong Khang Tommy T1 - Über die antidepressiven Effekte sportlicher Aktivität: Eine Metaanalyse klinischer Studien zu potenziellen Wirkmechanismen N2 - In dieser Bachelorarbeit wurde untersucht, wie körperliche Aktivität als adjuvante oder nicht-pharmakologische Therapie bei Depressionen eingesetzt werden kann. Es wurden sowohl die antidepressiven Effekte als auch potenzielle Wirkmechanismen analysiert. Der theoretische Teil beleuchtet Depressionen, neurobiologische Prozesse sowie gängige Behandlungsansätze. Die Ergebnisse einer systematischen Literaturrecherche zeigen, dass körperliche Aktivität positive Effekte auf depressive Symptome, die maximale Sauerstoffaufnahme (VO2) und die Schlafqualität hat. Insbesondere individuelle Programme sind wirksam. Es wurden die Vor- und Nachteile der Sporttherapie erörtert, sowie Empfehlungen für zukünftige Forschung gegeben. KW - Sport KW - Depression KW - Antidepressiva KW - Effekte KW - Bewegung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-20348 ER - TY - THES A1 - Kösters, Dominic T1 - Production and Chromatographic Analysis of Polyhydroxybutyrate from waste product streams by Azohydromonas lata N2 - As conventional plastic production receives much criticism for being harmful to both humans and the environment, this work focused on establishing a batch fermentation based on waste substrates from local industries to produce polyhydroxybutyrate (PHB) with Azohydromonas lata (A. lata). Additionally, the produced PHB was characterised by qualitative and quantitative gas chromatography coupled to a mass spectrometer (GC-MS) and gel permeation chromatography (GPC). Multiple substrates, including rhubarb waste, pea waste, and dairy industry wastewater (KAAS medium), were tested for successful fermentation. Rhubarb and pea waste could not be used as a fermentation substrate due to obstacles in upstream processing. KAAS medium was prepared by centrifugation and sterile filtration and tested in a 1 L and 4 L fermentation yielding non-competitive biomass and PHB concentrations with 0.09 g/L and 0.004 g/L, respectively. A 3 L fermentation with pure saccharose as the carbon source served as a model for comparison and analysis and resulted in a measured biomass concentration of 3.58 g/L with a PHB content of 1.43 g/L after Soxhlet extraction. The GPC analysis led to no conclusive elograms and results due to issues in non-destructively extracting and solving the PHB. The GC-MS analysis showed excellent linearity with an R2 value of 0.9906 for the standard curve and clear chromatograms, which allowed for both qualitative and quantitative analysis of PHB. Since PHB concentrations from KAAS medium were low, no quantitative analysis could be performed. Only samples from the saccharose-based fermentation could be assessed quantitatively. The found maximum PHB concentration was 2.95 g/L, which deviated from the found 1.43 g/L after Soxhlet extraction and was therefore discussed in this work. No locally available waste substrate could be found to be suitable for an industrial scale fermentation. The findings during this work led to the conclusion that semi-sterile fermentation approaches shall be investigated in future works handling waste products as they can potentially overcome upstream processing steps and, hence, make rhubarb or pea waste a potential candidate for PHB production. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-4246 ER - TY - THES A1 - Klose, Marian T1 - Optimierung der Krebstherapie durch Inhibition von MDR1 N2 - MDR1 (Multidrug Resistance Protein 1) stellt ein Membranprotein dar, welches das Ziel hat, den Körper vor Toxinen und Xenobiotika zu schützen. Dieser Schutzmechanismus kann sich allerdings erheblich auf die Chemotherapie auswirken, indem Wirkstoffe aus der Zielzelle heraustransportiert werden. Da der Effekt von MDR1 in einigen Fällen unerwünscht ist, kommt es zum Einsatz von Inhibitoren. Diese lassen sich je nach Toxizität und Herkunft in verschiedene Kategorien einteilen. Diese Arbeit gibt zunächst einen wissenschaftlichen Hintergrund. Zuerst werden Multiwirkstoffresistenzen im allgemeinen beschrieben, bevor MDR1 genauer beleuchtet wird. Danach werden verschiedene Bereiche der Krebserkrankung erläutert, um im Anschluss die unterschiedlichen Klassen der Inhibitoren vorzustellen. Die Diskussion schildert schlussendlich sowohl Chancen als auch Risiken der Inhibition und setzt diese in ein Verhältnis. Zusammenfassend lässt sich sagen, dass es in der Chemotherapie vermehrt zu Wirkstoffresistenzen kommt. Krebszellen adaptieren und ändern ihre Genexpression, sodass altbewährte Medikamente nicht mehr greifen. Die Inhibition könnte dies umkehren, bringt aber zusätzliche Nebenwirkungen mit sich, sodass sich keine klare Empfehlung zugunsten der Inhibition von MDR1 geben lässt. KW - Krebs KW - MDR1 KW - P-Glykoprotein KW - Optimierung Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-4427 ER - TY - THES A1 - Schiffers, Lukas T1 - Optimization of RT-PCR Assays for the Roche cobas® 6800/8800 Utility Channel: Influence of 2´-O-Methyl modified Primers on PCR efficiency N2 - Automated, high-throughput real-time PCR instruments such as the cobas® 6800/8800 from Roche have revolutionized the operation in molecular diagnostics laboratories as they provide a complete process of patient samples including all necessary steps for PCR applications from material preparation up to the calculation and evaluation of final results with a minimum of user interaction. In addition to the broad spectrum of commercially available ready-to-use reagent kits for blood screenings, virologic and microbiological assays as well as tests designed for women’s health, the cobas® 6800/8800 provides a tool which allows users to develop and implement their own tests onto the high-throughput device. Equipped with this tool, called the cobas® omni Utility Channel, these automated instruments serve a high flexibility and can be adjusted to users’ personal needs. Notwithstanding the advantages of the Utility Channel, a limited number of lab developed tests have been implemented onto the cobas® 6800/8800 so far as no guideline for the optimization and transfer of such tests onto the Utility Channel has been provided to the public yet. In the course of this bachelor thesis, four real-time PCR assays, including an allele-specific duplex test for HLA-B27, an established in-house test for the differentiation and detection of Ureaplasma urealyticum/parvum, a published assay for the detection of Chlamydia trachomatis as well as a duplex reverse-transcription assay for the detection and differentiation of norovirus genogroup one and two have been optimized for the use on Utility Channel. Furthermore, 2´-O-Methyl modified primers have been integrated into the optimization process of all assays to asses their influence on PCR efficiency. Three of these four assays have been transferred successfully onto a cobas® 6800 following a developed method which lead to the final design of a flowchart guideline for the optimization of lab developed tests for the use on a cobas® 6800/8800 system. KW - PCR efficiency KW - Modified primers KW - Methylated primers KW - Cobas KW - Molecular biology Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-4632 ER - TY - THES A1 - Hoffmann, Annika T1 - Prüfung eines Anlagenreinigungsprozesses in der Kosmetikindustrie und vergleichende Analyse der Wirksamkeit der eingesetzten Reinigungsmittel und Desinfektionsmittel N2 - Kosmetika haben einen hohen Stellenwert in unserer heutigen Gesellschaft und der pro Kopf Konsum der immer vielfältiger werdenden Produkte wächst stetig an. Um einen hohen Sicherheits- und Qualitätsstandard des Kosmetikums zu gewährleisten, ist die Sauberkeit der Produktionsanlage fundamental [IKW, 2019; DIN EN ISO 22716: 2008]. Die chemischen und mikrobiologischen Parameter, welche das Reinigungsergebnis beeinflussen, wurden am Beispiel der Tubenabfüllanlage der bb med. product GmbH untersucht und bewertet. Die chemische Rückstandsanalyse, welche mittels pH-Wert Messung der letzten Spülflotte durchgeführt wurde, diente dem Nachweis von Peressigsäurerückständen. Die Messergebnisse lieferten keinen Verdacht auf gesundheitsgefährdende Rückstände in der Produktionsanlage. Der mikrobiologische Zustand der Anlagenoberflächen wurde mittels Tupferverfahren überprüft. Die Auswertung zeigte, dass die Oberflächenkeimzahl gegenüber dem Richtwert um ein Vielfaches erhöht war. Die Wirksamkeit der eingesetzten Prozesschemikalien wurde in praxisnahen Versuchen ermittelt, bei denen Polyvinylchlorid-Oberflächen und Edelstahloberflächen artifiziell mit verschiedenen Matrices aus Sheabutter und Rinderblutserum kontaminiert wurden, in welche die Prüfkeime Staphylococcus aureus und Pseudomonas aeruginosa eingebettet wurden. Die Simulation verschiedener Anwendungsbedingungen zeigte signifikante Korrelationen zwischen dem Reduktionsfaktor, der Beschaffenheit des Oberflächenmaterials und der Art der Anschmutzung. Auf Edelstahl ließen sich konstant höhere Reduktionen erzielen als auf den PVC-Oberflächen. Des Weiteren konnte die fetthaltige Sheabutter Kontamination mit einer verminderten Wirksamkeit der Reinigungsmittel und insbesondere der Desinfektionsmittel assoziiert werden. Der zusätzliche Einfluss mechanischer Energie trug nicht eindeutig zur Steigerung der Reduktionsleistung bei. Zwischen den geprüften Desinfektionsmitteln auf der Basis von Glutaraldehyd, Isopropanol und Peressigsäure konnten keine signifikanten Wirkungsunterschiede festgestellt werden. Das alkalische Reinigungsmittel, welches auf Alkohol- und Alkoholethoxylatbasiert, wies in einigen Versuchsreigen mit P. aeruginosa eine signifikant höhere Wirksamkeit als Sodium-Laureth-Sulfat und Sodium-Coco-Sulfat auf. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-5378 ER - TY - THES A1 - Marx, Clara T1 - Untersuchungen zur Hygiene in städtischen Kitas unter besonderer Berücksichtigung von Lebensmittelkontaktflächen N2 - Das Ziel dieser Arbeit war, verschiedene Faktoren zu identifizieren, die einen Einfluss auf die Keimbelastung in Küchen von Kindertagesstätten (KiTa) haben können. Dazu wurden in 28 städtischen KiTas Abklatschproben von Arbeitsoberflächen (AO) und Trockentüchern (TT) genommen, wobei TSA und MacConkey-Agar verwendet wurde. Die Proben wurden anschließend bebrütet und die Ergebnisse statistisch ausgewertet. Drei Faktoren hatten einen geringfügig signifikanten Einfluss auf die Gesamtkeimzahl (GK). Diese drei Faktoren waren das Reinigen der Arbeitsoberflächen nach jedem Arbeitsschritt (Einfluss auf GK TSA/MacConkey, AO), der Zeitpunkt der Beprobung nach 12 Uhr (Einfluss auf GK TSA, TT) und eine Waschtemperatur von über 60°C (Einfluss auf GK TSA, TT). Wobei letzterer Zusammenhang zwecks fehlender Evidenz eventuell als falsch positiv gewertet werden muss. Der Zutritt für Kinder zur Küche erwies sich als stark signifikanter Einflussfaktor (p<0,05) auf die Gesamtkeimzahl an Enterobacteriaceae (d.h. KbE auf MacConkey-Agar) auf den Arbeitsoberflächen. Durch die Ergebnisse der Arbeit konnte die Notwendigkeit für Hygiene-Schulungen unterstrichen werden, die nicht nur das Küchenpersonal, sondern auch Erzieher und vor allem Kinder mit einbeziehen. Zudem konnte gezeigt werden, dass übermäßiges Reinigen der Oberflächen eher zu einer Erhöhung der Keimzahl führt als zu einer weiteren Verringerung, was vermutlich vor allem auf einen erhöhten Eintrag von Keimen über Putzutensilien zurückzuführen ist. Alle verwendeten Materialien sollten daher bei Verwendung immer in einwandfreiem Zustand sein. KW - Lebensmittel KW - Hygiene KW - Kindergarten Y1 - 2020 ER - TY - THES A1 - Kerst, Mario T1 - Validation and optimization of mathematical predictive models for the identification of microorganisms using Raman-spectroscopy N2 - The identification and classification of microorganisms remains a challenge in many areas, especially considering time and cost-efficiency. Fast, reliable and cheap methods are of great interest for research, industry and health care. Raman spectroscopy is a method that fulfills these criteria and, in this work, we aim to show its effectiveness to classify a selection of microorganisms. Using a standardized protocol, eighteen microorganisms were measured using Raman spectroscopy and classified with several types of mathematical classification models, including linear discriminant analysis, support vector machines and convolutional neural networks. To prepare the measured spectral data for classification several steps for the data evaluation and transformation were applied and their effectiveness for removing noise and other interferences evaluated. The resulting predictions outcomes were compared to select the most efficient model, showing that with an overall true positive prediction rate of 86.87 % the convolutional neural network performed the best. Further inspection of the results shows issues with the measurements of selected organisms, indicating that an improved measurement protocol is required to achieve proper predictions. Overall this work shows that Raman spectroscopy in combination with mathematical classification models is a viable and fast method for classification of microorganisms. KW - Raman spectroscopy KW - Microbiology KW - Linear discriminant analysis KW - Support vector machine KW - Convolutional neural network Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-14820 ER - TY - THES A1 - Viyof Ful, Flavian T1 - The effects of P53 stabilitization in SMARCB1-deficent, deficent TP53- wildtype epitheliod sarcoma cells N2 - Epithelioid sarcomas (ES) which are a rare form of soft tissue sarcomas are known to afflict both males and females with a slight bias for males. They are characterised by a defective SMARCB1 gene as well as a TP53 wildtype. Owing to this distinctive trait, it was hypothesised that reactivating p53 protein could hold therapeutic advantage in these type of tumours since p53 is a transcription factor at the crossroads between cell survival or death. P53 downstream target genes regulate the cell cycle or promote apoptosis. Since p53 is inactivated by its natural inhibitor, MDM2, in these types of tumours (Claudia Schaffner et al. 1999), using an MDM2 inhibitor to disrupt the P53-MDM2 interaction and stabilise p53 offered a sensible rationale to explore. It is often the case that cancer cells develop a resistance to a particular chemotherapy over time. Therefore, using a combination of two different inhibitors with completely different mechanisms of action to antagonise the tumour cells and prevent a possible recurrence was also considered. Two epithelioid sarcoma cell lines, VAESBJ and EPI544, were used for these experiments. HDM201, which is an MDM2 inhibitor, and doxorubicin, the current standard in threating epithelioid sarcomas, were both employed to be used as single agent treatments and in combination. Firstly, it had to be established that both cells are sensitive to the inhibitors in a dose dependent fashion. This was done using the MTS assay which quantifies cell viability based on the metabolism of tetrazolium salts and its eventual conversion to a purple soluble formazan residue by viable cells. Next, to further investigate the downstream effects of reactivated p53 in the cell populations, indirect immunofluorescence (IF) was performed to demonstrate that both inhibitors were capable of individually stabilising p53 in both cell lines. To further support the results from the indirect IF, western blot analysis was done to prove that p53 accumulates within the cell. Furthermore, quantitative polymerase chain reaction (PCR) was also performed to explore the extent to which p53’s stabilisation influences the fate of the treated cells. The results obtained from the MTS assay experiments showed that the cell lines used were indeed sensitive to both inhibitors as single agent treatments (EPI544 cells IC50 (HDM)= 0.212nM, IC50 (Dox)= 259.9nM) and VAESBJ IC50 (HDM)= 1.52µM, IC50 (Dox)= 17.5nM). At their respective IC50 values in combination, both drugs acted synergistically to halt cell viability in VAESBJ cell line whereas they were antagonistic against EPI544 cell line. However, these discrepancies were due to the dose response of the cells to the drugs. Moreover, from the IF analysis, p53 was clearly stabilised and as a result affected cell viability in all cell lines for both drugs. There was a considerable amount of p53 accumulation in treated cells when analysed by western blot. Lastly, the qPCR data showed that upon stabilisation, p53 upregulated the cell cycle checkpoint protein p21 as well as its natural regulator MDM2 because of a negative feedback loop meant to regulate the amount of p53 in normal cells. BCL2 which encodes an anti-apoptotic protein is also downregulated in all treated cells. Pro-apoptotic TP53I3 gene is significantly upregulated in the cell populations treated with the combination. In a nutshell, the results support the rationale that targeting MDM2 in ES tumours holds therapeutic value. They also highlight the usefulness of combination therapies as a better approach at targeting cancer cells. Although p53 is stabilised, its accumulation and downstream effects are largely dependent on whether it was achieved through posttranslational modifications or not. These results necessitate future research to characterise the effects of a combination of HDM201 and Doxorubicin on ES tumours in vivo. Y1 - 2022 ER - TY - THES A1 - Duarah, Meenakshi T1 - Healthy additions in dairy milk: A systematic literature review N2 - Dairy makes up a significant part of the diet as most individuals tend to include milk in their meals. Several studies have revealed that some of the health challenges experienced by humans are a result of some of the additives added to some of their foods. Various kinds of additions can be done in milk that is healthy to increase the consumption among the population or increase the nutrition value of milk. Such additions include flavours, vitamins, and minerals, chocolate, spices, and herbs, as well as fortification of milk products, etc. In the case of preservatives, potassium sorbate and sodium benzoate are added to milk which helps in inhibiting the growth of micro-organisms, preserves the freshness of milk, and prevents spoilage. Also, the concept of lactose-free dairy products is explained widely. Lactose is often present in almost all our dairy products, making it a challenge to those who suffer from lactose intolerance. The process of production of lactosefree milk is explained, which allows people to obtain the nutrients they need from food without compromising their health. The benefits of some of the additives of dairy products are determined methods of killing pathogens in milk also come into play in the research. This includes sterilization of milk which is a high treatment process that uses high temperature to get rid of pathogens. The study also explains the implications that come with the development of aroma and flavour in dairy products, the process of fortification of milk is also explained as a healthy addition to milk. Overall, this review paper shed light on the healthy additions in milk. The research also explores the effectiveness of the market trend of such additions in milk. Keywords: “Lactose free Milk”, “Healthy additions”, “Healthy benefits and Milk”, “Herbs and spices in Milk”, “Milk products”, “Milk market and Germany”, “Healthy addition or Chocolates”, “Turmeric milk”, “Cloves milk”, “Chocolate milk and milk products”, “Fortified milk and additions”, “Probiotics in milk”. Y1 - 2022 ER - TY - THES A1 - Demand, Victoria Maria T1 - Effect of the combination of fermentation and enzymatic hydrolysis on the functional properties, sensory profile and main allergens of pea protein isolates N2 - With a rising demand of ecological, healthy, safe and appealing protein alternatives, legumes, such as peas (Pisum sativum), become more and more important in the food industry as they can fulfil these demands to provide plant-based protein alternatives. To be successful on the food market, it is important to develop ingredients with no or low allergic potential, good functional properties, and appealing sensory characteristics. Treating pea protein isolates (PPI) with enzymatic hydrolysis (EH) and lactic acid fermentation (F) can result in high-quality protein alternatives. In this study, PPI was hydrolysed for 120 min with three different enzymes (papain, Esperase®, trypsin) in combination with a 24 h lactic acid fermentation (L. plantarum). The treatments were performed either with enzymatic hydrolysis first (HF) or with fermentation first (FH). The molecular weight distribution and the degree of hydrolysis (DH) were analysed to determine the treatment’s effect on potential pea allergens. The protein solubility (PS), emulsifying capacity (EC), and foaming properties were investigated. The sensory profile was evaluated by 11 panellists, who ranked the samples by the attributes “plant-like” and “bitter”. The FH combination samples with Esperase® and trypsin did not apparently show potential allergen fractions. The highest degree of hydrolysis of combined treatments was obtained by the HF_Esperase® sample (10.76 %), whereas FH_papain showed the lowest (3.92 %). The protein solubility was improved by all samples that were hydrolysed. At pH 7.0, HF_Esperase® increased the protein solubility up to 67.28 % and the only fermented PPI showed the lowest (10.72 %). At pH 4.5, FH_Esperase® showed the highest protein solubility (66.55 %) and the fermented PPI the lowest (5.72 %). The highest emulsifying capacity was reached by the untreated PPI (730 mL/g), whereas the lowest was reached by HF_Esperase®. The highest foaming capacity was shown by FH_trypsin (2575 %) and the lowest by the fermented PPI (808 %). The most stable foam was built by the untreated PPI (77 %); any of the samples treated with Esperase® and trypsin were not able to form a stable foam. The most “bitter” sample was FH_Esperase® and the least was FH_papain. The untreated PPI was rated the most “plant like”, whereas FH_trypsin was rated the least “plant like”. Overall, the combination of EH and F changed the molecular weight distribution of the PPI, apparently degrading the potential pea allergens. The combinations of the treatments showed good functional properties and reduced pea characteristic flavour. The chosen enzyme as well as treatment conditions and sequence should be considered to develop high quality PPI ingredients. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-12700 ER - TY - THES A1 - Birkenbach, Gesa T1 - Quantitative real-time PCR Detection of Yersinia ruckeri for Application in Aquaculture N2 - To detect pathogen infections in aquaculture early and reduce their impact, a photonic biosensing chip is being developed in the PHOTO-SENS project, to enable fast and easy routine testing in aquaculture facilities. One target bacterial pathogen is Yersinia ruckeri, the causative agent of enteric redmouth disease. Detection is based on short DNA sequences (probes), that are complementary to the DNA of their target pathogen. In this work, a Yersinia ruckeri-specific probe was designed together with a set of qPCR primers. The probe and primers were tested in qPCR experiments, including quantifi- cation of extracted DNA, specificity and sensitivity testing, and detection of bacterial DNA from highly diluted samples to mimic the detection of environmental DNA. Three different standard series were created for the quantification of unknown samples. The influence of fish tissue on detection was tested, and the efficiency of Chelex-DNA ex- tractions were compared to peqGOLD Tissue DNA Mini Kit extractions. During quantification experiments with a first standard series (Y1P), the quantification output of most samples was 12–175 times higher than expected. The lower limit of detection was at 100 copies based on that standard, with an efficiency of 88%. The discrepancy was reduced with a gBlocks standard (limit of detection: 5 copies; effi- ciency: 92%). A CFU standard provided quantification results in reasonable agreement with expected CFU starting quantities (limit of detection: 1 CFU; efficiency: 106%). De- tection of diluted samples after filtration was possible. Chelex DNA extractions yielded higher amounts of detectable DNA compared to a DNA extraction kit. Less bacterial DNA was extracted in bacterial culture samples containing fish tissue than in samples that did not contain fish tissue. Higher-than-expected quantification outputs were attributed to flaws in the creation of a first standard series as well as detectable DNA from dead cells or clusters that were not accounted for in the expected starting quantities. The gBlocks standard was as- sumed to be most reliable for quantification of exact copy numbers, while the CFU standard produced results that could be accounted for in CFU counts. As these chal- lenges concerned the standard series’ and not the probe itself, it was concluded that the probe was suitable for application in the PHOTO-SENS project for detection of Yersinia ruckeri. KW - Quantitative real-time PCR (qPCR) KW - Yersinia ruckeri KW - DNA quantification KW - Hydrolysis probe KW - Aquaculture Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-16361 ER - TY - THES A1 - Rümmele, Yvonne T1 - Advantages and disadvantages of mulching in market garden systems N2 - The need for sustainable and resilient food production is constantly increasing. Methods such as cover cropping, the use of mulches and non- or minimal tillage are recommended in large-scale agriculture, yet are not typically found in standard versions of market gardening, as developed by J.M. Fortier. In order to redesign the market gardening system towards more sustainability, the advantages and disadvantages of mulching, possible allelopathic effects from cover crops and mulches, and a possible on-site production of transfer and insitu mulch, were investigated. For this purpose, a literature review was carried out and afterwards a market garden rotation including cover crops was designed. The review results suggested that positive (crop-promoting) as well as negative (crop- and weed-reducing) allelopathy from cover crops exist and are includable into the system as a form of integrated weed management system. It was found that the advantages of mulching outweigh the disadvantages and that it is possible to redesign the market garden system towards more sustainability. KW - Market gardening KW - Allelopathy KW - Intercropping KW - Cover crops KW - Mulch Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-17025 ER -