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1

Bariera hydrofobowa blon lipidowych. Wplyw cholesterolu i nienasyconych lancuchow alkilowych lipidow na transport czasteczek polarnych

100%
Wisniewska A., Subczynski W. K.
Postępy Biologii Komórki. Suplement
|
1995
|
nr 05
59-72
2
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Transport elektronów a zmiany płynności błon tylakoidów w czasie transformacji etioplastów w chloroplasty

100%
Subczynski W. K., Machowicz E.
Zeszyty Problemowe Postępów Nauk Rolniczych
|
1984
|
nr 271
3

The liquid-ordered phase in sphingomyelin-cholesterol membranes as detected by the discrimination by oxygen transport [DOT] method

100%
Wisniewska A., Subczynski W. K.
Cellular and Molecular Biology Letters
|
2008
|
tom 13
|
nr 3
430-451
Membranes made from binary mixtures of egg sphingomyelin (ESM) and cholesterol were investigated using conventional and saturation-recovery EPR observations of the 5-doxylstearic acid spin label (5-SASL). The effects of cholesterol on membrane order and the oxygen transport parameter (bimolecular collision rate of molecular oxygen with the nitroxide spin label) were monitored at the depth of the fifth carbon in fluid- and gel-phase ESM membranes. The saturation-recovery EPR discrimination by oxygen transport (DOT) method allowed the discrimination of the liquid-ordered (l o), liquid-disordered (l d), and solid-ordered (s o) phases because the bimolecular collision rates of the molecular oxygen with the nitroxide spin label differ in these phases. Additionally, oxygen collision rates (the oxygen transport parameter) were obtained in coexisting phases without the need for their separation, which provides information about the internal dynamics of each phase. The addition of cholesterol causes a dramatic decrease in the oxygen transport parameter around the nitroxide moiety of 5-SASL in the l o phase, which at 50 mol% cholesterol becomes ∼5 times smaller than in the pure ESM membrane in the l d phase, and ∼2 times smaller than in the pure ESM membrane in the s o phase. The overall change in the oxygen transport parameter is as large as ∼20-fold. Conventional EPR spectra show that 5-SASL is maximally immobilized at the phase boundary between regions with coexisting l d and l o phases or s o and l o phases and the region with a single l o phase. The obtained results all owed for the construction of a phase diagram for the ESM-cholesterol membrane.
4

Three-dimensional dynamic structure of the lipid bilayer membranes: An EPR spin label study

100%
Subczynski W. K., Wisniewska A.
Cellular and Molecular Biology Letters
|
1996
|
tom 01
|
nr 4
Over the last decade we have investigated the effects of cholesterol, polar carotenoids, and integral proteins (peptides) on the structure, dynamics, and hydrophobicity of saturated and unsaturated phosphatidylcholine (PC) membranes. The major results obtained in our studies can be summarized as follows: (1) The effect of unsaturation on the membrane alkyl chain order and reorientational motion is negligibly small; (2) The translational diffusion of lipids (lateral or vertical) as well as the diffusion of lipid-soluble small molecules is significantly decreased in cis- and trans-unsaturated PC membranes; (3) cis-unsaturated alkyl chains greatly decrease the ordering effect of membrane modifiers (cholesterol, polar carotenoids) as well as their effect on alkyl chain reorientational motion; (4) Introduction of a double bond into the alkyl chain increases the hydrophobicity (decreases water penetration) at all locations in the membrane; (5) Incorporation of cholesterol (30 mol%) decreases hydrophobicity (increases water penetration) from the polar headgroup region to a depth of approximately C7 and C9 for saturated and unsaturated PC membranes, respectively. Membrane hydrophobicity sharply increases at these positions from the level of methanol to the level of pure hexane, and hydrophobicity is constant in the inner region of the membrane.
5

Effect of carotenoides on oxygen transport within and across model membranes

100%
Subczynski W. K., Markowska E.
Current Topics in Biophysics
|
1992
|
tom 16
|
nr 2
6

Physical properties of lipid bilayer membranes: relevance to membrane biological functions

100%
Subczynski W. K., Wisniewska A.
Acta Biochimica Polonica
|
2000
|
tom 47
|
nr 3
Over the last 25 years one of us (WKS) has been investigating physical properties of lipid bilayer membranes. In 1991 a group led by WKS was organized into the Laboratory of Structure and Dynamics of Biological Membranes, the effective member of which is AW. Using mainly the electron paramagnetic resonance (EPR) spin-labeling method, we obtained unexpected results, which are significant for the better understanding of the functioning of biological membranes. We have developed a new pulse EPR spin-labeling method for the detection of membrane domains and evaluation of lipid exchange rates. This review will be focused on our main results which can be summarized as follows: (1) Unsaturation of alkyl chains greatly reduces the ordering and rigidifying effects of cholesterol although the unsaturation alone gives only minor fluidizing effects, as observed by order and reorientational motion, and rather significant rigidifying effects, as observed by translational motion of probe molecules; (2) Fluid-phase model membranes and cell plasma membranes are not barriers to oxygen and nitric oxide transport; (3) Polar carotenoids can regulate membrane fluidity in a way similar to cholesterol; (4) Formation of effective hydrophobic barriers to the permeation of small polar molecules across membranes requires alkyl chain unsaturation and/or the presence of cholesterol; (5) Fluid-phase micro-immiscibility takes place in cis-unsaturated phosphatidylcholine-cholesterol membranes and induces the formation of cholesterol-rich domains; (6) In membranes containing high concentrations of transmembrane proteins a new lipid domain is formed, with lipids trapped within aggregates of proteins, in which the lipid dynamics is diminished to the level of gel-phase.
7

Can macular xanthophylls replace cholesterol in formation of the liquid-ordered phase in lipid-bilayer membranes?

81%
Subczynski W. K., Wisniewska-Becker A., Widomska J.
Acta Biochimica Polonica
|
2012
|
tom 59
|
nr 1
 Lateral organization of membranes made from binary mixtures of dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC) and macular xanthophylls (lutein or zeaxanthin) was investigated using the saturation-recovery (SR) EPR spin-labeling discrimination by oxygen transport (DOT) method in which the bimolecular collision rate of molecular oxygen with the nitroxide spin label is measured. This work was undertaken to examine whether or not lutein and zeaxanthin, macular xanthophylls that parallel cholesterol in its function as a regulator of both membrane fluidity and hydrophobicity, can parallel other structural functions of cholesterol, including formation of the liquid-ordered phase in membranes. The DOT method permits discrimination of different membrane phases when the collision rates (oxygen transport parameter) differ in these phases. Additionally, membrane phases can be characterized by the oxygen transport parameter in situ without the need for separation, which provides information about the dynamics of each phase. In gel-phase membranes, two coexisting phases were discriminated in the presence of macular xanthophylls - namely, the liquid-ordered-like and solid-ordered-like phases. However, in fluid-phase membranes, xanthophylls only induce the solitary liquid-ordered-like phase, while at similar concentrations, cholesterol induces coexisting liquid-ordered and liquid-disordered phases. No significant differences between the effects of lutein and zeaxanthin were found.
8

Carotenoid-membrane interactions in liposomes: effect of dipolar, monopolar, and nonpolar carotenoids

81%
Wisniewska A., Widomska J., Subczynski W. K.
Acta Biochimica Polonica
|
2006
|
tom 53
|
nr 3
9

Partitioning and transport of spin labeled drugs in model membranes

81%
Wojas J., Pezeshk A., Pezeshk V., Subczynski W. K.
Biophysics of Membrane Transport
|
1990
|
tom 10
|
nr 2
10

New mechanism in the protective action of carotenoids in membranes

81%
Markowska E., Sielewiesiuk J., Subczynski W. K.
Biophysics of Membrane Transport
|
1990
|
tom 10
|
nr 2
11

Wpływ znaczników spinowych - nitroksylowych pochodnych kwasu stearynowego na główne przejście fazowe błony dimirystoilofosfatylocholinowej

81%
Wisniewska A., Nishimoto Y., Kusumi A., Subczynski W. K.
Current Topics in Biophysics. Supplement
|
1992
|
tom 16
12

The cis-carotenoid-membrane interactions

81%
Widomska J., Subczynski W. K., Gruszecki W. I., Strzalka K.
Acta Biologica Cracoviensia. Series Botanica. Supplement
|
2011
|
tom 53
|
nr 1
13

Mikroskopowa sonda tlenowa. Tlenometria ERP

81%
Ligeza A., Wisniewska A., Subczynski W. K.
Current Topics in Biophysics. Supplement
|
1992
|
tom 16
14

Zorientowana krystalizacja metaloporfiryn: wplyw pola magnetycznego i blon lipidowych.

81%
Subczynski W. K., Pasienkiewicz-Gierula M., Antholine W. E.
Postępy Biologii Komórki. Suplement
|
2001
|
tom 16
285-296
15

Structural aspects of antioxidant activity of lutein in models of photoreceptor membranes

81%
Wisniewska-Becker A., Nawrocki G., Duda M., Subczynski W. K.
Acta Biologica Cracoviensia. Series Botanica. Supplement
|
2011
|
tom 53
|
nr 1
16

Structural aspects of the antioxidant activity of lutein in a model of photoreceptor membranes

81%
Wisniewska-Becker A., Nawrocki G., Duda M., Subczynski W. K.
Acta Biochimica Polonica
|
2012
|
tom 59
|
nr 1
Lateral organization of membranes made from binary mixtures of dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC) and macular xanthophylls (lutein or zeaxanthin) was investigated using the saturation-recovery (SR) EPR spin-labeling discrimination by oxygen transport (DOT) method in which the bimolecular collision rate of molecular oxygen with the nitroxide spin label is measured. This work was undertaken to examine whether or not lutein and zeaxanthin, macular xanthophylls that parallel cholesterol in its function as a regulator of both membrane fluidity and hydrophobicity, can parallel other structural functions of cholesterol, including formation of the liquid-ordered phase in membranes. The DOT method permits discrimination of different membrane phases when the collision rates (oxygen transport parameter) differ in these phases. Additionally, membrane phases can be characterized by the oxygen transport parameter in situ without the need for separation, which provides information about the dynamics of each phase. In gel-phase membranes, two coexisting phases were discriminated in the presence of macular xanthophylls - namely, the liquid-ordered-like and solid-ordered-like phases. However, in fluid-phase membranes, xanthophylls only induce the solitary liquid-ordered-like phase, while at similar concentrations, cholesterol induces coexisting liquid-ordered and liquid-disordered phases. No significant differences between the effects of lutein and zeaxanthin were found.
17

Profile polarności w poprzek błon fosfatydylocholinowych na granicy lipidów i gramicydy

81%
Wisniewska A., Hyde J. S., Kusumi A., Subczynski W. K.
Current Topics in Biophysics. Supplement
|
1992
|
tom 16
18

Reoxidation of the reduced nitroxide radical spin label tempone: involvement of oxygen and oxygen-derived active forms

81%
Wisniewska A., Ligeza A., Subczynski W. K.
Current Topics in Biophysics
|
1992
|
tom 16
|
nr 2
19

Spin-label oximetry in dense cell suspensions: Problems in closed-and open-chamber methods

81%
Ligeza A., Swartz H. M., Subczynski W. K.
Current Topics in Biophysics
|
1994
|
tom 18
|
nr 1
20

Paraffin oil particles as microscopic probes for oxygen measurements in biological systems: ESR spin-label oximetry

81%
Ligeza A., Wisniewska A., Subczynski W. K.
Current Topics in Biophysics
|
1992
|
tom 16
|
nr 2
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