Wyniki wyszukiwania - Biblioteka Nauki

1

Cell outer membrane mimetic surface as a material with improved hemocompatibility

100%

Trzaskowski M. , Butruk B. , Ciach T.

Challenges of Modern Technology

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2011

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tom Vol. 2, no. 4

7--10

EN

The phenomenon of blood coagulation on the surfaces of implantable devices such as artifi cial blood vessels, valves or hearts is the major problem that has to be taken into consideration during the construction of such devices. Since the main factor that has an infl uence on clotting of blood is the surface of the material the device is made of, numerous attempts has already been undertaken to modify surfaces of existing materials in order to provide necessary protection against clot formation, very often by coating the materials with bio-active substances. The aim of presented study was to create a coating of phosphatidylcholine that would mimic natural cell outer membrane on the surface of polyurethane — a material already in use in construction of cardiovascular implants. The obtained coated materials have been evaluated with the use of FT-IR/ATR spectroscopy. The change in contact angle of modifi ed material was also investigated. Finally in vitro cytotoxicity tests were performed in order to examine biocompatibility of obtained material.

2

Influence of bolaamphiphilic steroid dimer on formation and structure of bilayer lipid membranes

88%

Kalinowski S. , Lotowski Z. , Morzycki J. W.

Cellular and Molecular Biology Letters

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1999

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tom 04

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nr 2

3

Increasing surface charge density induces interdigitation in vesicles of cationic amphiphile and phosphatidylcholine

88%

Ryhanen S. J. , Alakoskela J. M. I. , Kinnunen P. K. J.

Cellular and Molecular Biology Letters

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2005

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tom 10

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nr Suppl.

4

Time and temperature dependence of liposome UV spectra

88%

Michnik A. , Zawada Z.

Cellular and Molecular Biology Letters

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1999

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tom 04

|

nr 2

5

A simple TLC-MALDI method to monitor oxidation products of phosphatidylcholines and -ethanolamines

75%

Bischoff A. , Eibisch M. , Fuchs B. , Süss R. , Schürenberg M. , Suckau D. , Schiller J.

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2011

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tom Vol. 23, no. 2

365--375

EN

The analysis of lipid-phospholipid oxidation products is of primary importance. Although there are established HPLC and LC-MS techniques, it is shown here for the first time that the combination of matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and TLC represents a sensitive, fast, and convenient alternative. A mixture of 1-palmitoyl-2-linoleoyl-sn-phosphatidylcholine (PLPC) and -ethanolamine (PLPE) was oxidized under the influence of atmospheric oxygen and characterized by direct positive ion MALDI-TOF MS as well as combined TLC-MALDI. It is shown that much more detailed information — particularly related to the oxidation products of PLPE that have so far been scarcely investigated — can be obtained by TLC-MALDI. However, it is also shown that further methodological improvements are necessary to make this method generally applicable to complex lipid mixtures.

6

Physicochemical analysis of phosphatidylcholine-ceramide system in bilayer lipid membranes

75%

Naumowicz M. , Petelska A. D. , Figaszewski Z. A.

Acta Biochimica Polonica

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2008

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tom 55

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nr 4

721-730

EN

Electrochemical impedance spectroscopy was used for the study of two-component lipid membranes. Phosphatidylcholine and ceramide were to be investigated, since they play an important biochemical role in cell membranes. The research on biolipid interaction was focused on quantitative description of processes that take part in a bilayer. Assumed models of interaction between amphiphilic molecules and the equilibria that take place there were described by mathematical equations for the studied system. The possibility of complex formation for two-component system forming bilayers was assumed that could explain the deviation from additivity rule. Equilibria were described by mathematical equations that were further verified experimentally. The determined values of parameters (stability constant, molecular area of complex, capacitance and conductance of the lipid membranes formed from molecules and complexes) were used for calculation of model curves. The comparison of model curves and experimental points verified the assumed model

7

Molecular dynamics simulation studies of lipid bilayer systems.

75%

Pasenkiewicz-Gierula M. , Murzyn K. , Róg T. , Czaplewski C.

Acta Biochimica Polonica

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2000

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tom 47

|

nr 3

601-611

EN

The main structural element of biological membranes is a liquid-crystalline lipid bilayer. Other constituents, i.e. proteins, sterols and peptides, either intercalate into or loosely attach to the bilayer. We applied a molecular dynamics simulation method to study membrane systems at various levels of compositional complexity. The studies were started from simple lipid bilayers containing a single type phosphatidylcholine (PC) and water molecules (PC bilayers). As a next step, cholesterol (Chol) molecules were introduced to the PC bilayers (PC-Chol bilayers). These studies provided detailed information about the structure and dynamics of the membrane/water interface and the hydrocarbon chain region in bilayers built of various types of PCs and Chol. This enabled studies of membrane systems of higher complexity. They included the investigation of an integral membrane protein in its natural environment of a PC bilayer, and the antibacterial activity of magainin-2. The latter study required the construction of a model bacterial membrane which consisted of two types of phospholipids and counter ions. Whenever published experimental data were available, the results of the simulations were compared with them.

8

The activity of DGAT and PDAT enzymes in the developing seeds of Brassica napus

75%

Demski K. , Furmanek T. , Jasieniecka K. , Banas A.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

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nr 3

9

Associating oligonucleotides with positively charged liposomes

75%

Jurkiewicz P. , Okruszek A. , Hof M. , Langner M.

Cellular and Molecular Biology Letters

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2003

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tom 08

|

nr 1

EN

Oligonucleotides (ODNs) are short (up to 30 bases) fragments of single-stranded nucleic acids that are used as sequence specific regulators of gene expression and anti-sense based therapeutics. ODNs are frequently aggregated with particulates in order to improve their pharmacological characteristics. Complexes of ODN and lipid aggregates are among the most commonly mentioned in the literature. In order to control the formation and final properties of such aggregates, a detailed description of how ODN interacts with the lipid surface is needed. In this paper, we present the results of fluorescence measurements regarded an association of 20 base ODN, labelled with fluorescein, and a lipid surface containing various amount of positive charge. Unilamellar lipid vesicles were formed from egg phosphatidylcholine (PC) and various amounts of the cationic lipid l,2-dioleoyl-3-trimethylammonium- propane (DOTAP). It was found that about 20 mol% of DOTAP in the lipid bilayer suffices to obtain complete ODN association. This result was further confirmed via measurements performed by fluorescence correlation spectroscopy (FCS). These in turn showed that the diffusion time of labelled ODN in the presence of cationic liposomes decreases. Also, the particle number and count rate were reduced, concurring with conclusions derived from steady state fluorescence spectroscopy results.

10

Photoaddition of psoralens to phosphatidylcholine in micelles. Cell membrane, a target for PUVA therapy

75%

Waszkowska E. , Poznanski J. , Zaremba Z.

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1994

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tom 12

|

nr 2

11

The effect of dexamethasone on phosphatidylcholine species composition in fetal rat lungs

75%

Stettner S. , Ledwozyw A.

Archivum Veterinarium Polonicum

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1995

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tom 35

|

nr 1-2

12

Properties of lipid bilayers modified by long-chain polyprenols

75%

Walinska K. , Janas T. , Chojnacki T. , Swiezewska E. , Janas T.

Cellular and Molecular Biology Letters

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1997

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tom 02

|

nr 1

13

The effect of some phenyltin compounds on thermotropic behaviour of mixed phosphatidylcholine-cholesterol bilayers

75%

Rozycka-Roszak B. , Pruchnik H. , Kaminski E.

Cellular and Molecular Biology Letters

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1999

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tom 04

|

nr 2

14

The hypoglycaemic response of diabetic rats to insulin-liposomes

63%

Petkowicz J. , Byra A. , Szumilo T.

Acta Physiologica Polonica

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1990

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tom 41

|

nr 1-3

EN

Petkowicz J., Byra A., Szumiło T: The hypoglycaemic response of diabetic rats to insulin-liposomes. Acta Physiol. Pol., 1990 41(1-3): 97-103. We prepared insulin-liposomes using one combination of lipids including phosphatidylcholine (cholesterol) stearylamine, 7/2/1 (molar ratio). Non-sonicated liposomes (LMV) and sonicated liposomes (SUV) contained about 20% and 5% of insulin, respectively. Free insulin was removed from liposomes-associated insulin by ultracentrifugation, or ultrafdtration on Sepharose 6B column. Insulin preparations were administered parenterally and non-parenterally into male, Wistar rats with alloxan diabetes to produce the hypoglycaemia. In case of i.v. and s.e. routes of administration all preparations acted in the similar manner giving the clear hypoglycaemia after 2 h. When administered intragastrically only liposome insulin caused hypoglycaemia. In case of buccal and nasal routes of administration only SUV-insulin was effective.

15

Biophysical changes induced by cholesterol on phosphatidylcholine artificial biomembranes containing alamethicin oligomers

63%

Cernescu A. , Luchian T.

Open Physics

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2006

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tom 4

|

nr 2

155-167

EN

Cholesterol is an important constituent of eukaryotic cell membranes, whose interaction with phospholipids leads to a broad range of biological roles, such as: maintenance of proper fluidity, formation of raft domains, reduction of passive permeability of various chemical species through the bilayer (e.g., glucose, glycerol, K+, Na+ and Cl− ions), and increased mechanical strength of the membrane. In this work we studied an interesting paradigm, as to whether cholesterol-containing phosphatidylcholine biomembranes influence the kinetics and transport features of alamethicin oligomers embedded into it. We demonstrate that moderate relative amounts of cholesterol increase the electrical conductance of various sub-conductance states of the alamethicin oligomer, caused probably by a non-monotonic change in the lumped dipole moment of the biomembrane. Our data suggest that biomembrane stiffness caused by cholesterol, visibly modifies the association-dissociation rates of alamethicin oligomerization in the biomembrane. Moreover, increasing concentrations of cholesterol seem to lead to more stable intermediate alamethicin oligomers. We show that in the presence of cholesterol, as the diameter of the alamethicin oligomer increases, so does the time of another monomer to get picked up. These results brings into focus the interesting issue of how oligomerization of proteins affects their interaction affinities for membrane-based lipids.

16

Defining sex differences in selected lipid metabolites of blood plasma in Wistar rats

63%

Leskanicova A. , Chovancova O. , Babincak M. , Blicharova A. , Kolesarova M. , Macekova D. , Kostolny J. , Smajda B. , Kiskova T.

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tom 70

|

nr 4

17

Wpływ nanorurek węglowych występujących w powietrzu środowiska pracy na układ oddechowy człowieka

63%

Kondej D.

Bezpieczeństwo Pracy : nauka i praktyka

|

2019

|

tom nr 1

19-23

PL

Nanorurki węglowe stanowią ważną grupę nanomateriałów. W artykule przedstawiono ich krótką charakterystykę oraz występowanie w powietrzu środowiska pracy. Omówiono budowę układu oddechowego człowieka, który jest główną drogą narażenia zawodowego na nanorurki węglowe oraz mechanizmy jego oczyszczania ze zdeponowanych cząstek. Zaprezentowano wyniki badań wpływu wybranych nanorurek węglowych na właściwości powierzchniowe monowarstwy utworzonej z fosfatydylocholiny, która jest głównym składnikiem surfaktantu płucnego.

EN

Carbon nanotubes are an important group of nanomaterials. The article presents their short characteristics and their presence in the air of work environment. The structure of the human respiratory system that is the main way of occupational exposure to carbon nanotubes, and mechanisms of its purification from deposited particles were discussed. The results of research on the influence of selected carbon nanotubes on the surface properties of a monolayer formed from phosphatidylcholine, which is the main component of the pulmonary surfactant, are presented.

18

The effect of the lipid-binding site of the ankyrin-binding domain of erythroid beta-spectrin on the properties of natural membranes and skeletal structures

63%

Chorzalska A. , Lach A. , Borowik T. , Wolny M. , Hryniewicz-Jankowska A. , Kolondra A. , Langner M. , Sikorski A. F.

Cellular and Molecular Biology Letters

|

2010

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tom 15

|

nr 3

406-423

EN

It was previously shown that the beta-spectrin ankyrin-binding domain binds lipid domains rich in PE in an ankyrin-dependent manner, and that its N-terminal sequence is crucial in interactions with phospholipids. In this study, the effect of the full-length ankyrin-binding domain of β-spectrin on natural erythrocyte and HeLa cell membranes was tested. It was found that, when encapsulated in resealed erythrocyte ghosts, the protein representing the full-length ankyrin-binding domain strongly affected the shape and barrier properties of the erythrocyte membrane, and induced partial spectrin release from the membrane, while truncated mutants had no effect. As found previously (Bok et al. Cell Biol. Int. 31 (2007) 1482–94), overexpression of the full-length GFP-tagged ankyrin-binding domain aggregated and induced aggregation of endogenous spectrin, but this was not the case with overexpression of proteins truncated at their N-terminus. Here, we show that the aggregation of spectrin was accompanied by the aggregation of integral membrane proteins that are known to be connected to spectrin via ankyrin, i.e. Na+K+ATP-ase, IP3 receptor protein and L1 CAM. By contrast, the morphology of the actin cytoskeleton remained unchanged and aggregation of cadherin E or N did not occur upon the overexpression of either full-length or truncated ankyrin-binding domain proteins. The obtained results indicate a substantial role of the lipid-binding part of the β-spectrin ankyrin-binding domain in the determination of the membrane and spectrin-based skeleton functional properties.

19

Cationic phospholipids: physical properties, complexes with DNA and transfection activity

63%

MacDonald R. C. , Ashley G. W. , Shida M. M. , Rakhmanova V. A. , Choi K. L. , Pantazatos D. P. , Tarahovsky Y. S. , Kennedy M. T. , Pozharski E. V. , Rosenzweig H. S. , Pantazatos S. P. , Stearns J. A. , Hashimoto A. , Mcintosh T. J.

Cellular and Molecular Biology Letters

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1999

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tom 04

|

nr 2

20

Capacitance and resistance of the bilayer lipid membrane formed of phosphatidylcholine and cholesterol

63%

Naumowicz M. , Petelska A. D. , Figaszewski Z. A.

Cellular and Molecular Biology Letters

|

2003

|

tom 08

|

nr 1

EN

Capacity and electric resistance of lipid membranes composed of lecithin and cholesterol were determined. The components were chosen for the study because they were present in biological membranes. Capacitance of the lecithin and cholesterol membranes amounts to 0.38 and 0.61 μF/cm2, and resistance to 1.44xl04 and 2.12x 106 Ω cm2, respectively. A 1:1 complex appears as a result of lecithin-cholesterol membrane formation. Parameters of the membrane formed of the lecithin-cholesterol complex were determined: surface concentration (Γ3), capacitance (C3), and conductance (R 31), as well as the stability constant (K) of the complex. The mean values of those magnitudes are as follows: 4.265xl0-6 mol/m2, 0.54 μF/cm2, 1.381xl0-6 Ω-1 cm-2 and 3.748x107, respectively.