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Ovesen, Marte Stokvik (Master thesis; Mastergradsoppgave, 15-Nov-2012)[+][-]
Abstract: Kliniske studier viser at inntak av omega-3 fettsyrene EPA, DPA og DHA kan bidra til å forebygge hjerte- og karsykdommer, redusere inflammasjon, påvirke sentralnervesystemets funksjon positivt og bidra til en rekke andre helsegevinster. Som en konsekvens har markedet for kommersielle omega-3 produkter økt de siste tiårene. Det ble kjøpt inn 10 produkter til dette studiet. Produktene baserte seg på konsentrert fiskeolje, selolje, krillolje, tran og en blanding av tran og konsentrert fiskeolje. Varedeklarasjonene synes å være mangelfull ettersom det bare opplyses om mengde EPA/DPA/EPA per dose, og ikke hvilke andre fettsyrer produktene inneholder og mengden av disse. Dessuten opplyser de færreste om hvilke lipidklasser fettsyrene er forestret i. Hovedmålet for oppgaven ble derfor å bestemme fettsyresammensetningen i produktene, bestemme prosentandelen av de ulike fettsyrene og å bestemme hvilke lipidklasser de ulike produktene inneholdt. Det skulle også gjøres en klassespesifikk analyse av fettsyresammensetningen. Ettersom teknikkene for separasjon av lipidklasser anses å være utstyrskrevende og tidskrevende ble delmål for oppgaven å lage en ny metode for å separere lipidklasser til videre analyse. Det ble brukt GC-FID til analyse av fettsyresammensetning og bestemmelse av arealprosent. Til separasjon av lipidklasser ble det forsøkt preparativ HPTLC og fast-fase ekstraksjon på silika. Lipidklassene som ble funnet var sammenlagt mono, di- og triacylglyseroler, fosfolipider, frie fettsyrer, etylestere, kolesterylestere og/-eller voksestere og kanskje kolesterol. For fiskeoljene, tran og selolje dominerte triacylglyseroler, for blandingen av tran og konsentrert fiskeolje var innholdet 50/50 etylestere og triacylglyseroler og for krilloljene dominerte fosfolipidene. Fettsyresammensetningen i produktene viste seg å være svært lik. Det var derimot stor variasjon i prosentandelen av de ulike fettsyrene og prosentandelen EPA, DPA og DHA varierte mellom ca. 70 og 15 %. Det var også store variasjoner i prosentandelen mettede og enumettede fettsyrer, mens prosentandelen flerumettede fettsyrer utenom EPA, DPA og DHA ikke varierte i stor grad. Det lyktes ikke å separere lipidklassene med preparativ HPTLC fordi det måtte appliseres for mye olje til at platen var i stand til å gi en god separasjon. Det lyktes heller ikke å lage en god metode for separasjon av lipidklasser med fast-fase ekstraksjon med silika som stasjonærfase, kanskje på grunn av for lav oppløsningsevne. Noen av lipidklassene ble imidlertid høvelig separert med den ene metoden som ble prøvd og fire av fraksjonene ble kjørt på GC-FID for FAME analyse. Resultatene av dette viste at det verken var stor forskjell i fettsyresammensetningen eller prosentandelen av fettsyrer i de ulike fraksjonene. URI: http://hdl.handle.net/10037/5094 File(s) in this item: 1
thesis.pdf (2.287Mb) -
Kostenko, Nataliya; Gottfriedsen, Jochen; Hilfert, Liane; Edelmann, Frank T (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: A synthetic route to potentially biocidal silsesquioxanes functionalized by quaternary pyridinium functionalities has been developed. N-Alkylation reactions of the precursor compounds 4-(2-(trimethoxysilyl)ethyl)-pyridine (5) and 4-(2-trichloro-silylethyl)pyridine (6) with iodomethane, n-hexylbromide, and n-hexadecylbromide cleanly afforded the corresponding N-alkylpyridinium salts (7–10). The synthesis of a 4-(2-ethyl)pyridine POSS derivative (2) was achieved by capping of the silsesquioxane trisilanol Cy7Si7O9(OH)3 (1) via two different preparative routes. Attempts to use compound 2 as precursor for quaternary pyridinium salt-functionalized POSS derivatives were met with only partial success. Only the reaction with iodomethane cleanly afforded the new N-methylpyridinium salt 12 in high yield, whereas n-hexylbromide and n-hexadecylbromide failed to react with 2 even under forcing conditions. URI: http://hdl.handle.net/10037/4923 File(s) in this item: 1
article.pdf (919.7Kb) -
Kahlke, Tim; Thorvaldsen, Steinar (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Cold-adaptation strategies have been studied in multiple psychrophilic organisms, especially for psychrophilic enzymes. Decreased enzyme activity caused by low temperatures as well as a higher viscosity of the aqueous environment require certain adaptations to the metabolic machinery of the cell. In addition to this, low temperature has deleterious effects on the lipid bilayer of bacterial membranes and therefore might also affect the embedded membrane proteins. Little is known about the adaptation of membrane proteins to stresses of the cold. In this study we investigate a set of 66 membrane proteins from the core genome of the bacterial family Vibrionaceae to identify general characteristics that discern psychrophilic and mesophilic membrane proteins. Bioinformatical and statistical methods were used to analyze the alignments of the three temperature groups mesophilic, intermediate and psychrophilic. Surprisingly, our results show little or no adaptation to low temperature for those parts of the proteins that are predicted to be inside the membrane. However, changes in amino acid composition and hydrophobicity are found for complete sequences and sequence parts outside the lipid bilayer. Among others, the results presented here indicate a preference for helix-breaking and destabilizing amino acids Ile, Asp and Thr and an avoidance of the helix-forming amino acid Ala in the amino acid composition of psychrophilic membrane proteins. Furthermore, we identified a lower overall hydrophobicity of psychrophilic membrane proteins in comparison to their mesophilic homologs. These results support the stability-flexibility hypothesis and link the cold-adaptation strategies of membrane proteins to those of loop regions of psychrophilic enzymes. URI: http://hdl.handle.net/10037/4922 File(s) in this item: 1
article.pdf (231.9Kb) -
Simpson, David; Benedictow, Anna; Berge, Halldis; Bergström, Robert; Emberson, Lisa D.; Fagerli, Hilde; Flechard, Chris R.; Hayman, Garry D.; Gauss, Michael; Jonson, Jan Eiof; Jenkin, Michael E.; Nyiri, Agnes; Richter, Cornelia; Semeena, Valiyavetil S.; Tsyro, Svetlana; Tuovinen, Juha Pekka; Valdebenito, Alvaro; Wind, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the model has covered all of Europe with a resolution of about 50 km × 50 km, and extending vertically from ground level to the tropopause (100 hPa). The model has changed extensively over the last ten years, however, with flexible processing of chemical schemes, meteorological inputs, and with nesting capability: the code is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols. In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for summer 2012. This publication is intended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and a brief background on some of the choices made in the formulation is presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe. URI: http://hdl.handle.net/10037/4915 File(s) in this item: 1
article.pdf (953.1Kb) -
Lindell, Kristoffer; Fahlgren, Anna; Hjerde, Erik; Willassen, Nils Peder; Fällman, Maria; Milton, Debra L (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Colonization of host tissues is a first step taken by many pathogens during the initial stages of infection. Despite the impact of bacterial disease on wild and farmed fish, only a few direct studies have characterized bacterial factors required for colonization of fish tissues. In this study, using live-cell and confocal microscopy, rainbow trout skin epithelial cells, the main structural component of the skin epidermis, were demonstrated to phagocytize bacteria. Mutant analyses showed that the fish pathogen Vibrio anguillarum required the lipopolysaccharide O-antigen to evade phagocytosis and that O-antigen transport required the putative wzm-wzt-wbhA operon, which encodes two ABC polysaccharide transporter proteins and a methyltransferase. Pretreatment of the epithelial cells with mannose prevented phagocytosis of V. anguillarum suggesting that a mannose receptor is involved in the uptake process. In addition, the O-antigen transport mutants could not colonize the skin but they did colonize the intestines of rainbow trout. The O-antigen polysaccharides were also shown to aid resistance to the antimicrobial factors, lysozyme and polymyxin B. In summary, rainbow trout skin epithelial cells play a role in the fish innate immunity by clearing bacteria from the skin epidermis. In defense, V. anguillarum utilizes O-antigen polysaccharides to evade phagocytosis by the epithelial cells allowing it to colonize rapidly fish skin tissues. URI: http://hdl.handle.net/10037/4914 File(s) in this item: 1
article.pdf (1.446Mb)
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