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Interakce liposomů s porfyriny studována pomocí Ramanovy spektroskopie kapkově nanášených povlaků
Vaculčiaková, Lenka ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Water-soluble cationic porphyrins have been studied in relation to antisense therapy and they have been successfully used to enhance the delivery of oligonu- cleotides to cells. The main focus of this study was to characterize the mech- anism of interaction of liposomes as model membranes, and porphyrins. We applied the drop coating deposition Raman spectroscopy (DCDR) to study com- plexes of liposomes and porphyrins. DCDR allowed us to measure complexes of low concentration as it uses the 'coffee ring' effect to concentrate the sample at the edge of a drop. We studied four different complexes combined of lipids: 1, 2−dipalmitoyl−sn−glycero−3−phosphocholine, 1, 2−dioleoyl−sn−glycero− 3 − phospho − (1 − rac − glycerol) and metalloporphyrins: copper 5, 10, 15, 20 − tetrakis(1 − methyl − 4 − pyridyl)porphyrin, copper 5, 10, 15, 20 − tetrakis(4 − sulfonatophenyl)porphyrin. We have found that the way these two components interact strongly depends on a specific lipid and porphyrin used. We observed partial incorporation of porphyrins into the liposome bilayer, their localisation to the surface of the liposome or the change of the conformation and ordering of lipid molecules. Moreover, we have found that the distribution of porphyrins in the dried drop is randomly non-homogenous. 61
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Artificial phospholipid membranes - method of prepatation, properties and their usage
Hryzáková, Klára ; Fišer, Radovan (advisor) ; Sýkora, Michal (referee)
Heterogenita biologických membrán vedla ke vzniku širokého spektra zjednodušených modelových systémů, jejichž uspořádání, velikost a tvar se dají přizpůsobovat různým aktuálním požadavkům. Existují dva rozdílné přístupy k vytváření umělých fosfolipidových membrán. První z nich je založen na vzniku membrán ve vodném prostředí. Do této skupiny patří černé lipidické membrány, dvojvrstvy na pevném podkladu, dvojvrstvy vzniklé z monovrstev na rozhraní vody a vzduchu a liposomy. Ve druhém případě vznikají dvojvrstevné membrány v množství organické fáze metodou dvojvrstev na kapičkovém rozhraní. Každý typ umělých membrán má své experimentální výhody a nevýhody, což se používá ke studiu různých problémů sahajících od chování jednotlivých fosfolipidů a proteinů až po fúze membrán. Umělé fosfolipidové membrány jsou vhodným nástrojem pro elektrickou charakterizaci dvojvrstev a nebo membránových proteinů. Tato práce je ucelený přehled nejpoužívanějších metod vhodných pro vznik umělých fosfolipidových membrán. Klíčová slova: membrána, lipid, fosfolipidová dvojvrstva, liposom, černá lipidová membrána, dvojvrstvy na pevném podkladu, dvojvrstva na kapičkovém rozhraní Abstract The heterogeneity of biological membranes has led to development of a wide spectrum of simplified model systems whose composition, size and...
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Adenylate cyclase toxin of Bordetella pertussis, its conformation and ion balance in host cell.
Motlová, Lucia ; Konopásek, Ivo (advisor) ; Krůšek, Jan (referee)
Adenylate cyclase (CyaA, ACT) toxin is one of the major virulence factors of Bordetella pertussis. Although CyaA binds to many types of membranes, it is assumed that the integrin CD11b/CD18 is its receptor which is expressed on the surface of myeloid cells. CyaA belongs to the family of RTX toxin-hemolysins. CyaA acts on the host cells by two independent activities. One of them is the conversion of ATP to cyclic AMP, which is catalyzed by adenylate cyclase (AC) domain after its translocation into the cytosol of the host cell, which leads to the entry of calcium cations into the host cell. Translocation is probably initiated by interaction of CyaA monomer with the target membrane. The second activity is the formation of CyaA channel selective for cations, which probably causes colloid osmotic lysis of target cells. The channel forming activity is provided by RTX hemolysin domain which most probably forms oligomers, although it was found that CyaA as a monomer causes leakage of potassium cations from the host cell. It is also not clear whether the oligomerization of CyaA would occur in solution, or after interaction with the host membrane. The aim of this study was to examine the flow of sodium ions on the membrane of murine macrophages J774A.1, which express integrin CD11b/CD18 on their surface....
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Study of liposomes by using of drop coating deposition Raman spectroscopy
Vodáková, Adéla ; Kočišová, Eva (advisor) ; Bednárová, Lucie (referee)
in english: Goal of the Bachelor Thesis was an optimization of liposome membrane preparation with different composition for the drop coating deposition Raman (DCDR) method, measuring of the DCDR spectra from dried droplets and their interpretation. The DCDR method lies in deposition of small volume of suspension (~μl) on special surface and measuring of Raman spectra from the ring formed at the edge of the dried droplet. The main advantage of used method is the possibility of measuring spectra from the sample with low concentration. Our results show that the DCDR method is very useful in studies of biological membranes with different composition. Two synthetic lipids and one natural extract were chosen for making a comparison. We have found out that spectra obtained from the ring of dried droplet are not different from the spectra measured in the suspension. The important characteristic of spectra is that dried droplet keeps the same lipid phase as in suspension. Spectral mapping proved good reproducibility of the signal inside the ring.
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