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1

The effect of hexadecaprenol on molecular organisation and transport properties of model membranes.

100%

Janas T., Nowotarski K., Gruszecki W. I., Janas T.

Acta Biochimica Polonica

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2000

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vol. 47

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issue 3

661-673

EN

The Langmuir monolayer technique and voltammetric analysis were used to investigate the properties of model lipid membranes prepared from dioleoylphosphatidylcholine (DOPC), hexadecaprenol (C80), and their mixtures. Surface pressure- molecular area isotherms, current-voltage characteristics, and membrane conductance-temperature were measured. Molecular area isobars, specific molecular areas, excess free energy of mixing, collapse pressure and collapse area were determined for lipid monolayers. Membrane conductance, activation energy of ion migration across the membrane, and membrane permeability coefficient for chloride ions were determined for lipid bilayers. Hexadecaprenol decreases the activation energy and increases membrane conductance and membrane permeability coefficient. The results of monolayer and bilayer investigations show that some electrical, transport and packing properties of lipid membranes change under the influence of hexadecaprenol. The results indicate that hexadecaprenol modulates the molecular organisation of the membrane and that the specific molecular area of polyprenol molecules depends on the relative concentration of polyprenols in membranes. We suggest that hexadecaprenol modifies lipid membranes by the formation of fluid microdomains. The results also indicate that electrical transmembrane potential can accelerate the formation of pores in lipid bilayers modified by long chain polyprenols.

2

Translocation of polysialic acid across model membranes: Kinetic analysis and dynamic.

100%

Janas T., Krajiński H., Timoszyk A., Janas T.

Acta Biochimica Polonica

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2001

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vol. 48

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issue 1

163-173

EN

Transmembrane translocation of polyion homopolymers takes place in the case of polyanionic polysialic acid (polySia), polyanionic polynucleotides and polycationic polypeptides. The purpose of this work was to determine the role of membrane electrical parameters on the kinetics of polyion translocation, the influence of polysialic acid on ion adsorption on positively charged membrane surface and the dynamics of the phospholipid hydrocarbon chains and choline group by using 1H-NMR. The analysis of polyion translocation was performed by using the electrical equivalent circuit of the membrane for the initial membrane potential equal to zero. The changes in polysialic acid flux was up to 75% after 1 ms in comparison with the zero-time flux. Both a decrease of membrane conductance and an increase of polyion chain length resulted in the diminution of this effect. An increase of praseodymium ions adsorption to positively charged liposomes and an increase of the rate of segmental movement of the -CH2 and -CH3 groups, and the choline headgrup of lipid molecules, was observed in the presence of polySia. The results show that the direction of the vectorial polyion translocation depends both on the membrane electrical properties and the degree of polymerization of the polymer, and that polysialic acid can modulate the degree of ion adsorption and the dynamics of membrane lipids.

3

The effect of undecaprenol on bilayer lipid membranes

75%

Janas T., Chojnacki T., Świeżewska E., Janas T.

Acta Biochimica Polonica

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1994

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vol. 41

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issue 3

351-358

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3 Acta Biochimica Polonica

1 2001

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3 Janas T.

1 Chojnacki T.

1 Gruszecki W. I.

1 Krajiński H.

1 Nowotarski K.

1 Timoszyk A.

1 Świeżewska E.

The effect of hexadecaprenol on molecular organisation and transport properties of model membranes.

Translocation of polysialic acid across model membranes: Kinetic analysis and dynamic.

The effect of undecaprenol on bilayer lipid membranes