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Titel
Comparison of the permeabilities of large unilamellar phospholipid vesicles and Aquaporin 1 proteoliposomes in the gel and fluid states / Author Johann Wachlmayr, BA, BSc
AutorInnenWachlmayr, Johann
Beurteiler / BeurteilerinPohl, Peter
Betreuer / BetreuerinPohl, Peter
ErschienenLinz, 2018
Umfang61 Blätter : Illustrationen
HochschulschriftUniversität Linz, Masterarbeit, 2018
SpracheEnglisch
DokumenttypMasterarbeit
URNurn:nbn:at:at-ubl:1-24406 Persistent Identifier (URN)
Zugriffsbeschränkung
 Das Werk ist gemäß den "Hinweisen für BenützerInnen" verfügbar
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Comparison of the permeabilities of large unilamellar phospholipid vesicles and Aquaporin 1 proteoliposomes in the gel and fluid states [3.63 mb]
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Zusammenfassung (Englisch)

Aquaporins are highly selective water channels. Moreover, glycerol and several neutral solutes permeate aquaglyceroporins. A controversially discussed issue is though the role of aquaporins in gas and especially in CO2 permeation. This Masters thesis is concerned with the question if there are lipid membranes with such low intrinsic carbon dioxide permeabilities, that CO2 transport can be directly measured and furthermore if functional Aquaporin 1 (AQP1) can be reconstituted into those liposomes. Permeability measurements were done for a variety of phosphatidylcholines varying in fatty acid chain lengths and saturation in both liquid-crystalline and gel-phase. Pf was detected by monitoring vesicle shrinkage due to an applied sucrose gradient and the resulting change in scattered light with a stopped flow device. For measuring PCO2 a pH sensitive dye was used and upon CO2 transport into the vesicle acidifying the liposome lumen, a change in fluorescence intensity could be detected. This work presents several liposomes composed of lipid membranes in gel phase, which indeed represent a barrier to carbon dioxide. The CO2 transport through these liposomes could directly be shown and the corresponding values for PCO2 have been determined. AQP1 was successfully reconstituted into Oleoylstearoylphosphatidylcholine (OSPC) proteoliposomes. Osmotic water permeability measurements confirmed the proteins functionality but its carbon dioxide permeability rate constant comes close to the resolution limit of the stopped flow device and CO2 transport through the protein could yet neither be shown, nor excluded. Further experiments of AQP1 in OSPC proteoliposomes with improvements on reconstitution process, detergent removal or buffer conditions, for instance, may still solve the question, whether AQP1 passes CO2 or not.

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